ABSTRACT. At a time where sustainable development is by and large a fundamental requirement for economic growth and development, hydrocarbon exploration – and in particular natural gas exploration– is going to be a primary element of the Greek economy’s energy mix. What is more, in tandem with the pipeline projects (Trans-Adriatic Pipeline, East-Med) they form the main concerns of the country’s energy plans.

In that sense, geosciences play an important role in every stage of those projects. As they progressively develop even from the first exploration phases of the concession areas from basic desktop geological, geophysical and economical studies, activities will require a well-trained and highly-skilled competent workforce that will match the needs of the operating companies.

Needless to say, given the long-term investments in the E&P industry (25 to 30 years), there will have to be efficient and well-organized training plans in place coupled with the necessary conditions that will allow Greece to build a competitive workforce. This should and will open up a new chapter in geoscience education from today.

ABSTRACT. System is a set of things working together as parts of a mechanism or an interconnecting network forming a unified whole. A complex system is a system composed of many components which is organized for a common purpose, an infrastructure such as power grid of transportation or communication systems, they interact with each other in a complex whole. Examples of complex systems are Earth's atmosphere and the global climate, organisms, the animal’s brains, ecosystems, a living cell and ultimately the entire universe. Can we consider the Earth as a complex System? Does it meet the criteria to be named system? Presents a great diversity? Consists of many parts? What are the properties links of its parts? What interdependence? Can one's sub-system work alone? Has an organization? These are some question concerning the Earth as a unity to be answered today. Gaia, the ancient Greek goddess personifying the Earth in its role as the beginning of life, is self-existent and unborn, the Big Mother, the Almighty Goddess. Gaia actually personifies the general cosmic frame within life is being evolved, or better to say, Gaia itself constitutes an integral system with life. Furthermore, Gaia represents a significant, scientific hypothesis (theory) of the last forty years which views the Earth in its entirety as a hyper- organism. Which are though the facts that geoscientists have nowadays at their disposal in order to adopt a stance towards this conjunction and why do we turn to myths again? From cognitive and psychological view, every myth is catalytic for the human way of thinking, as it simplifies the inexplicit scientific approaches through narration. No matter how many doubts might have been raised concerning the myth, it is still considered to be a primary form of historicity. Carried by the word, it is a quite philosophical and mainly pedagogic way of conveying knowledge; an allegoric attestation. Earth is regarded as a planet with life on its surface. However, a new view has already begun to emerge: Earth is a living planet itself where “inorganic” and “organic” forms and processes are integrated in a single, integral unity. It is a new approach regarding Earth’s operation and the life which rises from it and develops billions of years now on it’s sheer and lissom crust and on the so called biosphere with indistinct and limited boundaries. The matter of the constantly renewable biosphere has been recycled many times, both on the surface and inside the Earth, so as to maintain a constant bidirectional relation between the “inorganic” and “organic” matter (see bio-geochemistry or bio-geosciences). Geology explores an enormous and significant part of our natural world. As per its definition, Geology studies in fact the solid crust of the earth on which we live, move and create. A first contribution of Geology was the study and understanding of the so called “inorganic” world, namely the study and classification of the rocks of Earth’s crust, the rocks’ components, the minerals and the understanding of the structure of matter from the amorphous to the crystal level. However, beyond the description of the composition of Earth’s crust and the structure of its components, the most important contribution of Geology towards this direction was the large extent of understanding of the formation, destruction, transformation and recycling of our planet’s materials, where life itself is the main geological factor. The “geological cycle”, that is the rocks and minerals transformation cycle, and the dynamics of this ceaseless procedure take place in the geological time dimension. There is a permanent and impressive mobility in geological time which is difficult to be anticipated by man, as he has formed the perception that Earth is static, inorganic, steady, a “terra firma”, due to his restricted empirical perception of geological time. Geological knowledge plays a significant role in understanding and partially explaining time. Geological time starts in present time and goes through the recorded history of humanity. It runs the paleontological history of human beings that goes up to 5 million years back, of mammals (60-100 million years), of life on land (500 million years), of the beginning of life on our planet (3,5 billion years), of Earth’s generation (4,6 billion years). Within this period, the mountains, the valleys, the extension and the position of the seas, which seem ageless compared to the man’s life scale, change rapidly and systematically so as if they are in a permanent motion under the influence of very strong powers. A geological evolution interdependent biological evolution. The Earth has been divided in Geospheres from the deepest Nucleus, to Mantle, Lithosphere, Hydrosphere, Atmosphere, Biosphere etc. The knowledge of the inner structure of our planet - an achievement of the early 20th century, Alfred Wegener’s “Theory of Continental Drift”, the “Theory of Seafloor Spreading” and mainly the “Theory of Plate Tectonics”, also known as the “Theory of New Global Tectonics”, which integrates the big geological and geophysical phenomena into a coherent unity, only in the last quarter of the 20th century, offered a satisfying explanation for orogenesis, (mountain building), volcanism, seismic activity, petrogenesis (creation and development of rocks), mineralization and primarily the Earth’s crust kinematics, an a holistic view of Earth’s processes. The above mentioned theories concede the continent’s movement, i.e. the movement of land, a concept that is firmly established in man’s consciousness as a reference point for stability. In this sense, these theories can be related to Galileo’s theory supporting that “the earth moves”, which had such a radical impact on the evolution of human thought. The recent “Theory of Plate Tectonics” that dominates today the world of geosciences and can be epistemological characterized as a “model”, “assumption” or “paradigm (example)” after the statement of the historian of geosciences and philosopher Thomas Kuhn, has the characteristics of a big and important scientific conception: Simplicity, Universality, Globality and Completeness, as it generalizes and unifies on a planet scale every single local geological effect. Before the formulation of the Theory of Plate Tectonics, there was a fragmentary approach to the single geological phenomenon while the relevant theories-assumptions were incomplete and non-generalized. The Theory provides now a single and clear mechanism to explain all geological phenomena. So, time is ripe to think globally, that is holistic view. The Theory of Plate Tectonics constitutes a significant contribution of geosciences to human thought. The fact that it is tough on all educational levels and that it is widely spread on a scientific as well as a popular science level– mainly due to its simplicity- have made it very popular and show how significant it is. This Theory of Plate Tectonics, or better to say, “The generalized hypothesis”, has provided the expert scientist with new tools of thinking and the average educated man with new possibilities of understanding his “home”, planet Earth. Earth’s lithosphere, in particular the continental crust, constitutes a unique feature of our planet as it is not met in other planets of our solar system. It owes its uniqueness primarily to two basic facts: the existence of water, a basic element of life, and its tectonic mobility. The “richness” of the surface water, the atmospheric water as well as the groundwater is impressive. The hydrosphere constitutes also a space of joined organic and inorganic processes. “We can consider the global ocean surrounding the earth exactly as the petals on a flower”. Earth’s magnetosphere, namely its substantial shield, extends up to 100 km over its surface. This is another outcome of the processes that take place in the inner part of earth, in particular in its core. The rest of the earth planets have inconsiderable magnetospheres. This exactly is another particularity of our planet Earth. However, the most significant uniqueness of our planet is life itself. The “lithospheric plates” mobility generates the earthquakes and the volcanoes. Α physiological process which influenced from the Earth’s interior and affects the Earth’s crust and surface. The volcanoes then generate, renew and partially recycle the lithosphere and the gasses of the atmosphere. If we consider our planet’s age as equivalent to the average age of a man, the renewal of big parts of the crust takes place approximately every three years. This renewability of earth’s crust influences the biosphere and generates geo-ecological system diversity, which is responsible for the amazing diversity in various forms of life. The crust’s mobility is directly connected with life, or is even part of life. The atmosphere’s composition, as it was formed in the first phases of its geological history and as it is preserved for over 500 million years now within some limits, which are considered to be optimal for life, played a decisive role in earth’s development into a living planet. The atmosphere constitutes in fact the main factor of life maintenance in cooperation with life itself. Its oxygen, a product of photosynthesis, bacterial fermentation and volcanic explosions is interdependent with life. The “Gaia” hypothesis points out that life is the climate regulator and the climate changes vary then within some limits, which are adequate for life maintenance. The strong bacteria, which constitute a primeval form of life, play even today the most important role in the animal-inorganic recycling. Bacteria are ubiquitous in every habitat on earth, under the most extreme life maintenance conditions; in volcanic craters, up to 4 km deep in the Earth’s crust, in the deepest points of oceans, in the deep thermal springs of the mid-ocean ridges. The bacteria participate even in the geological processes. Still, there are a lot of things concerning Earth’s dynamic which we do not understand. New scientific researches on the “geo-physiology” of the living planet provide a new way of viewing earth’s function as well as life’s function which is generated in earth and develops on its sheer crust, the so called biosphere. In fact, there is no biosphere in the sense we use the term for other geospheres –crust, mantel and core-. Life constitutes an integral part of the upper crust, mainly of its surface, and of the atmosphere. Life participates in the geological processes as a substantial factor. The development of this new scientific knowledge and view will offer us the possibility in the near future to obtain a better understanding of ourselves, as living objects within a broader object, our planet. In a holistic view Earth as a whole is considered as a System of Systems, in the theory of Chaos and Complexity, that is a Complex System, a new “Gaia”, an Active Planet or a “Living Planet”.

ABSTRACT. Figure 1. a) Geological map of the Eastern Rhodope-Thrace region of Bulgaria-Greece (adapted from Bonev et al., 2015a) and the U-Pb, 40Ar/39Ar and Rb-Sr geochronology there labeled by numbers in Myr., b) Density probability diagram, c) concordia diagram of the youngest detrital zircon in greywacke sample.

Background, Objectives and Methods Latest Jurassic-Early Cretaceous sedimentary rocks and Jurassic arc/back-arc related ophiolitic rocks constitute various units of the Cicrum-Rhodope Belt (CRB) in Bulgaria and Greece (e.g. Meinhold and Kostopoulos, 2013, Ivanova et al., 2015; Bonev et al., 2015a,b, and references therein). In Bulgaria, the basal strata of the Mandritsa unit of the CRB are built of recrystallized limestone to marble, which preserved their primary depositional layering (Fig. 1a). The marble hosts greywacke ranging in size from pebbles to blocks (Bonev, 2005). Both lithologies are metamorphosed to medium greenschist-facies and experienced ductile shear deformation (Bonev and Stampfli, 2011). These marble strata of the Mandritsa unit are considered to be Triassic in age by lithological similarity to fossil-bearing marble strata of the Makri unit exposed in the CRB of Thrace region in Greece (Boyanov et al., 1990). The depositional age of the basal marble strata in the Mandritsa unit is unknown. Here, we present U-Pb geochronology results from the greywacke hosted by marble, which provide necessary insights into the timing of the deposition of the marble strata at the base of the CRB Mandritsa unit, in Bulgaria. We applied U-Pb LA-ICP-MS technique on detrital zircons from the greywacke, following standard density and heavy liquids separation methods and cathodoluminescence (CL) imaging to obtain internal structure of the dated zircons. LA-ICP-MS analyses were performed in geochronology laboratory of the Geological Institute of the Bulgarian Academy of Sciences. Details on analytical procedures can be found in Bonev et al., (2019).

Results and Conclusions Zircon grains range in size between 80 µm and 300µm showing irregular fragments or crystals with a slightly rounded shape in CL images, which altogether suggest a short transport from the source area. In the CL images, the zircon grains display well-defined oscillatory zoning, as well as slightly obliterated homogeneous zoning patterns. The range of Th/U ratio in dated zircons varies between 0.11 and 0.75 except for two analyses in recrystallized zircon grains with Th/U ratios of 0.07 and 0.09. The obtained ages of detrital zircons range from 431.3 Ma to 144.3 Ma (Fig. 1b). Dominant age cluster comprises Carboniferous-Permian zircons whose analyses yielded concordant ages at 317.1±1.4 Ma to 257.1±2.9 Ma. Minor age clusters yielded Triassic ages (242.9±7.6 Ma, 233.7±3.6 Ma), a single Silurian age of 431.3 Ma and a concordant Jurassic age of 171.4±2.6 Ma defined by two analyses (Th/U=0.07 and 0.15). The only youngest zircon out of 105 zircon grains analyzed in the greywacke sample yielded an age of 144.3±1.9 Ma (Th/U=0.09), and hence, defines the maximum depositional age of the greywacke and the marble (Fig. 1c). The Paleozoic and Triassic detrital zircons age clusters are time-correspondent to the protolith ages of the meta-granitoids that build the Rhodope high-grade metamorphic basement underlying the CRB (Fig.1a). Jurassic arc-related magmatic rocks are also known from the CRB in Thrace region (Bonev et al., 2015a). Therefore, both Rhodope high-grade metamorphic basement and CRB magmatic rocks must have been the source for clastic sedimentary deposition of the greywacke in the basal marble of the Mandritsa unit. Berriasian ammonite of first appearance in Tithonian was reported in schist of the Makri unit of the CRB in Greece (Dimadis and Nikolov, 1997). Thus, biostratigraphic constraint and the maximum deposition radiometric age in this study reveal latest Late Jurassic sedimentation in the CRB of the Thrace region. Thus, we have reached the following conclusions: • In the CRB of Thrace region, the basal marble of the Mandritsa unit deposited in latest Late Jurassic (Tithonian). • Both Rhodope basement and CRB Jurassic rocks must have been the sedimentary source of continental provenance.

Acknowledgements The study was supported by the National Science Foundation of Bulgaria through grant DN04/6. References Bonev, N., 2005. Siliciclastic knockers in marbles of the Eastern Rhodope, Bulgaria: significance for depositional environment and tectonic setting. Annuaire de l’Universite de Sofia « St. Kliment Ohridski », Faculte de Geologie et Geographie, livre 1 Geologie 98, 29-42. Bonev, N., Stampfli, G., 2011. Alpine tectonic evolution of a Jurassic subduction-accretionary complex: deformation, kinematics and 40Ar/39Ar age constraints on the Mesozoic low-grade schists of the Circum-Rhodope Belt in the eastern Rhodope-Thrace region, Bulgaria-Greece. Journal of Geodynamics 52, 143-167. Bonev, N., Marchev, P., Moritz, R., Collings, D., 2015a. Jurassic subduction zone tectonics of the Rhodope Massif in the Thrace region (Northern Greece) as revealed by new U-Pb and 40Ar/39Ar geochronology of the Evros ophiolite and high-grade basement rocks. Gondwana Research 27, 760-775. Bonev, N., Marchev, P., Moritz, R., Filipov, P., 2015b. Timing of igneous accretion, composition, and temporal relation of the Kassandra-Sithonia rift-spreading center within the eastern Vardar suture zone, Northern Greece: insights into Jurassic arc/back-arc systems evolution at the Eurasian plate margin. International Journal of Earth Sciences 104, 1837-1864. Bonev, N., Filipov, P., Raicheva, R., Moritz, R., 2019. Timing and tectonic significance of Paleozoic magmatism in the Sakar unit of the Sakar-Strandzha Zone, SE Bulgaria. International Geology Review. https://doi.org/10.1080/00206814.2019.1575090. Boyanov, I., Ruseva, M., Toprakchieva, V., Dimitrova, E., 1990. Lithostratigraphy of the Mesozoic rocks from the Eastern Rhodope. Geologica Balcanica 20, 3-28. Dimadis, E., Nikolov, T., 1997. An ammonite find in the Makri unit (Berriasian, southeast Rhodopes, northeast Grece). Comptes Rendus de l’Academie bulgare des Sciences 50, 71-74. Ivanova, D., Bonev, N., Chatalov, A., 2015. Biostratigraphy and tectonic significance of lowermost Cretaceous carbonate rocks of the Circum-Rhodope Belt (Chalkidiki Peninsula and Thrace region, NE Greece). Cretaceous Research 52, 25-63. Meinhold, G., Kostopoulos, D.K., 2013. The Circum-Rhodope Belt, northern Greece: Age, provenance, and tectonic setting. Tectonophysics 595-596, 55-68.

ABSTRACT. We present new insights into the paleoecologic and neotectonic evolution of the southeastern part of the island of Rhodes. For this, we studied fossil benthic foraminiferal assemblages samples from a marine sediment section from the Lindos Bay Formation (Pefka E section) deposited at the SE coast of the Island of Rhodes during the early Pleistocene and developed a benthic foraminiferal-based transfer function to reconstruct tectonically-driven changes in paleo-water depths. We observed a high concentration of eutrophic/low oxygen tolerant species in the studied sediment section which suggests mesotrophic conditions in the NE Mediterranean Sea region during the early Pleistocene. We further obliquity and precession-driven fluctuations in the individual abundances of the most important benthic foraminiferal species that are related to a higher food availability during glacial compared to interglacial periods and enhanced rain fall and associated prolonged near-coastal phytoplankton blooms at times of Northern-Hemisphere insolation maxima. Most the early Pleistocene deep-sea sapropel intervals are characterized by an increase in eutrophic/low oxygen tolerant taxa and a decrease in oligotrophic taxa in the studied section suggesting a higher and seasonally prolonged riverine runoff and associated phytodetritus fluxes rather than dysoxic conditions at the sea floor during times of sapropel formation. Precession-corrected paleo-water depth estimates in the section indicate a series of substantial vertical tectonic motions during the early Pleistocene with averaged vertical rates between 4 and ~8-10 mm/yr for the respective subsidence-uplift cycles and likely portray local vertical motions of an individual paleovalley rather than long-term vertical tectonic motion of the entire island.

ABSTRACT. Holocene environmental changes of coastal areas with a high temporal resolution, can be derived by the multi-proxy analysis of sediment cores (e.g., Morhange et al., 2000; Triantaphyllou et al., 2010; Di Rita et al., 2011), while the study of benthic foraminifera assemblages together with radiocarbon dating is evidently the best tool to reveal the succession of past environmental conditions and, therefore, the alteration of physiographical settings (e.g., Cann et al., 2000; Horton et al., 2007; Koukousioura et al., 2012; Xiang et al., 2008). The Farasan Al Kabir island is one of the two main islands of the Farasan Bank, which lies in the southeastern part of the Red Sea, offshore the southwest Saudi Arabian coast (Fig. 1A), and consists of more than 128 islands covering a total land area of approximately 600 km2 (Khalil, 2012). In order to reconstruct the coastal paleoenvironments since the mid Holocene, a 3.3-m long sediment core sampling, was conducted and Matar-1 core was analyzed. A multidisciplinary approach was selected to reveal short-term changes, combining micropalaeontological (benthic foraminifera), stratigraphical, lithological, element geochemical, bulk mineralogical, and isotopic dating (14C) analyses. Thirty nine (39) samples were used for micropaleontological analysis and over than forty foraminiferal species were identified. Benthic foraminiferal assemblages of the studied core samples were generally rich, but a lot of broken specimens were observed. Thus, the broken-reworked ratio was calculated. The southeast coast of the Farasan Al Kabir Island is formed from uplifted reefal limestone. The arid low-lying topography includes hard rock formations, such as coral limestone plateau, cliffs and pediments, as well as soft-sediment formations, such as playa-like depressions located on plateau surfaces, alluvial fans and bajada, and sandy beaches. The mid Holocene evolution of the borehole area is resulted from the detailed analysis of five sedimentary units detected along the core Matar-1, and includes three distinct stages: (a) from 5253 ± 223 y cal BP to 3138 ± 223 y cal BP, carbonate coarse-grained material consisting of coral fragments, molluscs, calcareous algae and benthic foraminifera are deposited on a shallow marine fringing reefal platform. Foraminiferal density presents high values, while the fauna is characterized by the dominant Ammonia convexa and miliolids, along with the small rotaliids, elphidiids and Bolivina spp. (Fig. 1B). Faunal composition varies at around 3675 ± 215 y cal BP, consisting mainly by Neorotalia calcar and A. convexa and by fluctuating percentages of small rotaliids, Peneroplis spp. and miliolids. Density reaches high values and broken-reworked tests increase significantly suggesting a high energy environment, in accordance with the Farasan modern analogue (Abu-Zied et al., 2011), pointing to a nearshore backreef, and later (around 3138 ± 223 y cal BP) a reef ramp. (b) since 3040 ± 220 y cal BP foraminiferal density decreases abruptly, with broken-reworked tests presenting their highest values, suggesting that the borehole area obtains the characteristics of a high-energy beach that receives increasing inputs of terrigenous material; (c) subsequently, a supratidal backshore setting is established influenced mostly by terrestrial processes and occasionally by marine processes, as it is indicated by the decreasing and sometimes sporadic presence of benthic foraminifera, and recently, a sedimentary veneer consisting of terrigenous, carbonate and evaporite material is formed by terrestrial, mainly wadi and aeolian, processes. Acknowledgements The authors would like to thank Prof. F. Villeneuve and Dr. M. Mouton for their full support and collaboration during the research survey. We are indebted to HRH Prince Sultan Bin Salman Bin Abdulaziz Al Saud (President and Chairman of the Directors Board of the Saudi Commission for Tourism and Antiquities, SCTA), as well as to Dr Al-Saud, Professor Ali Al-Ghabbān (Vice-President of SCTA) and Dr Jamal Al Omar (Director General of SCTA), for granting permission to carry out the fieldwork. We also gratefully acknowledge the cooperation and help of Dr Al-Modare, Dr Mofareh and M. Aqīlī, members of SCTA in Jizān and Farasān. References Cann, J.H., Bourman, R.P., Barnett, E.J., 2000. Holocene foraminifera as indicators of relative estuarine-lagoonal and oceanic influences in estuarine sediments of the River Murray, South Australia. Quaternary Research 53(3), 378-391. Di Rita, F., Simone, O., Caldara, M., Gehrels, W.R., Magri, D., 2011. Holocene environmental changes in the coastal Tavoliere Plain (Apulia, southern Italy): a multiproxy approach. Palaeogeography, Palaeoclimatology, Palaeoecology 310(3), 139-151. Horton, B.P., Culver, S.J., Hardbattle, M.I., Larcombe, P., Milne, G.A., Morigi, C., Whittaker, J.E., Woodroffe, S.A., 2007. Reconstructing Holocene sea-level change for the central Great Barrier Reef (Australia) using subtidal foraminifera. Journal of Foraminiferal Research 37(4), 327-343. Khalil, H.M., 2012. Pliocene-Pleistocene stratigraphy and macrofauna of the Farasan islands, south East Red Sea, Saudi Arabia. Arabian Journal of Geosciences 5(6), 1223-1245. Koukousioura, O., Triantaphyllou, M.V., Dimiza, M.D., Pavlopoulos, K., Syrides, G., Vouvalidis, K., 2012. Benthic foraminiferal evidence and paleoenvironmental evolution of Holocene coastal plains in the Aegean Sea (Greece). Quaternary International 261, 105-117. Morhange, C., Goiran, J.P., Bourcier, M., Carbonel, P., Le Campion, J., Rouchy, J.M., Yon, M., 2000. Recent holocene paleo-environmental evolution and coastline changes of Kition, Larnaca, Cyprus, Mediterranean sea. Marine Geology 170(1), 205-230. Pavlopoulos, K., Koukousioura, O., Triantaphyllou, M., Vandarakis, D., Marion de Procé, S., Chondraki, V., Fouache, E., Kapsimalis, V., 2018. Geomorphological changes in the coastal area of Farasan Al-Kabir Island (Saudi Arabia) since mid Holocene based on a multi-proxy approach. Quaternary International 493, 198-211. Triantaphyllou, M.V., Kouli, K., Tsourou, T., Koukousioura, O., Pavlopoulos, K., Dermitzakis, M.D., 2010. Paleoenvironmental changes since 3000 BC in the coastal marsh of Vravron (Attica, SE Greece). Quaternary International 216(1), 14-22. Xiang, R., Yang, Z., Saito, Y., Fan, D., Chen, M., Guo, Z., Chen, Z., 2008. Paleoenvironmental changes during the last 8400 years in the southern Yellow Sea: benthic foraminiferal and stable isotopic evidence. Marine Micropaleontology 67(1), 104-119.

ABSTRACT. Nummulitid banks and depositional models have been the subject of many studies in Greece already since 19th century (eg., Philippson, 1890). Although numerous studies deal with nummulitid presence mainly in the Greek Thrace basin, the Mesohellenic basin and the external Hellenides, systematic morphometrical analysis has never performed. This study was undertaken to define biometric and morphological features of Greek nummulitids and to test the relative taxonomic importance of internal and external features for distinguishing biostratigraphically significant species. Nummulitid assemblages from six different localities in Greece were morphometrically investigated for the first time (Fig. 1). The aforementioned localities belong to alpine (Perivoli Grevena, Manoliasa Ioannina, Dervenakia and Tripoli) and molassic (Kirki Thrace from Thrace basin and Vasiliki Trikala from Mesohellenic basin) formations. The micropaleontological material was examined in thin sections, except for isolated specimens collected within the molassic deposits in the area of Kirki Thrace, which were studied in polished sections and split specimens. The scheme of identification includes the study of the external morphology of the isolated specimens (the shape of the test, the shape of septa filaments, the presence or the absence of the granules, their type of arrangement and the measurements on diameter and test thickness). Furthermore, the study of the internal morphology in equatorial sections, is including the observations on the shape of septa and the architecture of the chambers. Biometrical analysis has been performed on the morphological characteristics of both megalospheric and microspheric forms. The conducted measurements refer to thickness, diameter and radius of the whole test and all internal whorls. Specific measurements refer to the dimensions of the protoconch (only for A-form). The scheme for the identification of Nummulites is based mainly in Blondeau (1972), Less (1998), Less et al. (2011), Less and Özcan (2012), Özcan et al. (2009) and Schaub (1981). Statistical analysis of the biometric data, combined with the established systematic taxonomy, enabled us to identify eight different morphotypes potentially associated with different nummulitid species. Among them the most commonly identified was Nummulites perforatus group, with N. perforatus de Montfort (SBZ 17; Serra-Kiel et al., 1998) being its main representative together with Assilina exponens, dominating in the molassic sediments of Vasiliki Trikala and Kirki Thrace. Additionally, faunas from Dervenakia and Tripoli present identical species associations pointing to a Bartonian age. Furthermore, three different assemblages have been observed from Perivoli Grevena area, suggesting three distinguished deposits forming a continuous succession spanning Early to Late Eocene time interval. Although Manoliasa Ioannina nummulitic bank corresponds to a redeposited formation, it shows significant similarities to the Early Eocene Perivoli Grevena fauna. Our results contribute to a refined stratigraphic assessment and high resolution local and interregional correlations of studied alpine and post- alpine Eocene carbonate deposits from the Hellenic peninsula. References Blondeau, A., 1972. Les Nummulites. Librairie Vuibert. IGME, 1983. Geological Map of Greece, scale 1:5.000.000. Institute of Geology and Mineral Exploration, Athens. Less, G., 1998. Statistical data of the inner cross protoconch diameter of Nummulites and Assilina from the Schaub collection. Opera Dela Slovenska Akademija Znanosti in Umetnosti (4)34, 183-202. Less, G., Özcan, E., 2012. Bartonian-Priabonian larger benthic foraminiferal events in the Western Tethys. Austrian Journal of Earth Sciences Volume 105/1, 129-240. Less, G., Özcan, E., Okay, I.-A., 2011. Stratigraphy and Larger Foraminifera of the Middle Eocene to Lower Oligocene Shallow-Marine Units in the Northern and Eastern Parts of the Thrace Basin, NW Turkey. Turkish Journal of Earth Sciences 20, 793-845. Özcan, E., Less, G., Baldi-Beke, M., Kollanyi, K., Acar, F., 2009. Oligo-Miocene foraminiferal record (Miogypsinidae, Lepidocyclinidae and Nummulitidae) from the Western Taurides (SW Turkey): biometry and implications for the regional geology. Journal of Asian Earth Sciences 34, 740-760. Philippson, A., 1890. Über die Altersfolge der Sedimentformationen in Griechenland. Zeit. Deutsch. Geol. Gessel. 42, 150-159. Schaub, H., 1981. Nummulites et Assilines de la Téthys Paléogène; taxinomie, phylogenèse et biostratigraphie. Mémoires suisses de Paléontologie, Birkhäuser Bâle. Serra-Kiel, J., Hottinger, L., Caus, E., Drobne, K., Ferràndez, C., Jauhri, A.K., Less, G., Pavlovec, R., Pignatti, J., Samsó, J.M., Schaub, H., Sirel, E., Strougo, A., Tambareau, Y., Tosquella, J., Zakrevskaya, E., 1998. Larger foraminiferal biostratigraphy of the Tethyan Paleocene and Eocene. Bulletin de la Société Géologique de France 169, 281-299.

ABSTRACT. Introduction This work involves the paleoecological study of Pleistocene deposits from Magoula (northwestern Peloponnesus, Greece, Fig. 1), based on the analysis of microfaunal elements (basically ostracods). The study area has been chosen not only as a site of significant palaeontological interest where plant fossils, mammal bones and a wide range of different kinds of invertebrate and microfossils occur, but mainly because it belongs to the tectonically interesting Rio –Antirio basin, which is part of the Corinth rift. Rio basin is an asymmetric graben with a NW-SE trending, located between the mainland of Greece and NW Peloponnesus (Kontopoulos & Zelilidis 1997). The basin formed during the Upper Pliocene to Lower Pleistocene, due to WNW normal faults and NNE transfer faults (Doutsos et al. 1988, Parcharidis et al. 2009).

Figure 1. Map illustrating the position of the studied section.

Material & Methodology Microfaunal analyses were carried out on 133 samples collected every 20-40cm from a natural section in the area of Magoula (2.5 kilometers SE of University of Patras) with a total thickness of 31.30 meters. Sediment samples were washed through 500 and 63 μm mesh sieves. Microfossils were collected and studied under the stereoscope. Species determined based on previous studies of Mediterranean benthic taxa. The collected data were analyzed, relative abundance diagrams were prepared for each species. Furthermore, taphonomic indices (Right/Left valve ratio, Sex ratio, Adult/Juvenile ratio and Carapace/Disarticulated Valves ratio) were calculated for the most abundant species. Results and Discussion Out of the 133 sediment samples, 75 contained sufficient numbers of tests and valves (<10%-100%) for quantitative analyses, 53 were barren and 6 contained scarce specimens. According to the microfaunal analysis, 6 ostracod taxa, of which the most abundant were Cyprideis torosa (both un-noded and noded morphotypes) and Candona neglecta, 2 benthic foraminifera taxa, as well as some charophyte gyrogonites, freshwater gastropods, gastropod opercula and fragments were identified in the studied samples. Based on the relative abundance diagrams and the taphonomic indices three main units can be distinguished (Fig. 2). Unit 1 (0-14.60 m) consisting of clay is mainly characterised by the presence of C. torosa (both un-noded and noded morphotypes) and the minor contribution of Candona neglecta and Ilyocypris spp. Based on the taphonomic indices of C. neglecta, Unit 1 is characterized by the locally focused deposition of more easily transported juvenile valves (A/J ratio < 1:25 & R/L ratio > 1), thus representing hydrodynamic transport , whereas the taphonomic indices of C. torosa (Fig. 2) may represent an in situ death assemblage, with reduced taphonomic removal of juveniles which therefore can be characterized as a life assemblage (A/J ratio 1:12-1:4 & R/L ratio ≈1). Unit 2 (14.61-23.50 m) consists of barren sand and gravel layers ((Fig. 2), while Unit 3 (23.51-31.30 m) which consists of alternations of clay, mud and sand and is represented mainly by C. torosa (both un-noded and noded morphotypes), C. neglecta and small numbers of Ilyocypris spp. valves (Fig. 2). Based on the taphonomic indices of C. neglecta (A/J ratio < 1:25, R/L ratio ≈1 & C/D ratio >0), Unit 3 may reflect not only low-energy conditions, but also potential mass kill events associated with increased sedimentation rates (smothering via settling of fine-grained sediment from river flood discharge). On the other hand, based on the taphonomic indices of C. torosa (A/J ratio 1:10-1:2, R/L ratio ≈1 & C/D ratio >0 to a certain depth (24.30 m)) an in situ death assemblage can be considered, where possibly the taphonomic removal of most juveniles occurred (Fig. 2). At 24.30 meters, where the C/D ratio of C. torosa is 0.4 (the biggest), the highest abundance value of C. neglecta and the lowest abundance value of C. torosa are observed (Fig. 2), indicative of a high energy event. It can be concluded that generally a brackish environment with several variations in the percentage of salinity and the mean sea level occurred. Unit 1 can be characterized as a lagoon environment with a few freshwater influxes, Unit 2 as a coastal environment and Unit 3 as a lagoon environment with strong freshwater influxes and a possible flood event (24.10-24.30 m).

Figure 2. Stratigraphic column of the study section, taphonomic indices and relative abundance diagrams of selected species.

Conclusions According to micropalaeontological and taphonomic analysis palaeonvironmental changes occurred due to eustatism. Initially a lagoon system, due to sea level drop turned into a coastal environment, close to the emersion of the area (barren layers) and finally influenced by a river system with strong freshwater influxes. Moreover, the relative abundance diagrams and the taphonomic indices in combination with the stratigraphic column characterized a possible flood event at 24.10-24.30 meters. Acknowledgements I would like to thank the members of the laboratory of Palaeontology and Stratigraphy (Department of Geology, University of Patras). References Kontopoulos N., Zelilidis A., 1997. Depositional environments of the coarse-grained lower Pleistocene deposits in the Rio-Antirio basin, Greece. Proceedings International Symposium on Engineering Geology and the Environment, IAEG, Athens. Doutsos T., Kontopoulos N., Poulimenos G., 1988. The Corinth-Patras rift as the initial stage of continental fragmentation behind an active island arc (Greece). Basin Research, v. 1(3), p. 177–190. Parcharidis I., Kokkalas S., Fountoulis I., Foumelis M., 2009. Detection and Monitoring of active faults in Urban environments: Time series interferometry on the cities of Patras and Pyrgos (Peloponnese, Greece). Remote Sensing Journal, v. 1, p. 676-696.

ABSTRACT. Introduction The Pleistocene has been a period of continuous universal climatic turmoil due to the establishment of glacial and interglacial periods and their periodic alteration (Millankovic cycles) which stigmatized Quaternary climates and ecosystems. Ostracods can be found in a wide variety of environments from alpine lakes to abyssal basins (Schellenberg, 2007) being excellent palaeoenvironmental indicators (Rodriguez-Lazaro and Ruiz-Munoz, 2012). Their highly calcified bivalve carapace can be easily fossilized. Actually, they are among the small number of organisms that can be found not only in great numbers especially in transitional environments, but also they are environmentally sensitive to several factors such as salinity, water chemistry, substrate characteristics, temperature, oxygen and nutrient availability (Frenzel and Boomer, 2005). All these factors cause severe changes in the composition of the ostracod assemblages, even in the intraspecific level, and high endemism. The project’s main objective is to study the Pleistocene ostracods deriving from sedimentary successions from central and southern Greece. The different species that dominate each ecological niche, their morphology, distribution, systematics, history and ecological preferences are examined. Moreover, high quality SEM images of the respective ostracod species have been produced and can serve as reference point for future studies. The results of this project will cover a significant gap in the Greek ostracod record which is rather incomplete compared to that of central Europe.

Material and Methods A bibliographic review of Pleistocene sediments that can be found in central and southern Greece took place in order to detect possible sampling sites. The location of the selected sedimentary sequences was mapped and at least 10 samples from each study site were collected. The samples were transported and stored at the Laboratory of Palaeontology and stratigraphy of the University of Patras. Sediment samples were appropriately processed (using tap water and/or suitable chemicals such as perydrol and dried), using standard methods. The fossils were handpicked and sorted under a stereoscope. After the determination of the tests, down to the species level, using appropriate atlases and keys (e.g. Stereo Atlas), representative valves of each ostracod species were cleaned and SEM photographed. Additionally, published literature that concerns the identified species and their distribution and palaeoecology is being studied as a comparative tool for the results of the project.

Results & Discussion Pleistocene sediments have been recorded in several places throughout central and southern Greece (Fig.1). Lower Pleistocene sedimentary sequences have been found in Atalanti (Central Greece), in Messinia and Lakonia (Southern Peloponnese) and also in Kefalonia (Ionian Sea) and Kos islands (Aegean Sea). Lower to Middle Pleistocene sequences have been recorded in Megalopolis (Southern Peloponnese) and in Zakynthos Island (Ionian Sea) while Middle Pleistocene sediments can be found in Lesvos Island (Aegean Sea). In Ioannina and Kopais (central Greece) sediments of Middle to Early Pleistocene age can be found. Finally Upper Pleistocene sediments have been recorded all over Crete Island and in Argos (NE Peloponnese). In Elis (West Peloponnese) and across the Southern margin of the Corinth Gulf (Northern Peloponnese) sediments that cover all Pleistocene can be found as it is also the case for Rhodes Island and for Cyprus. For this reason these areas are considered particularrly important for the study of the Pleistocene evolution in central and Southern Greece. Most of the recorded Pleistocene sedimentary sequences were deposited in marine environments. Lacustrine sequences have been recorded in Megalopolis Basin and on Lesvos and Kos islands. Across the Southern margin of Corinth Basin and also in Cyprus the sedimentary sequences show marine, transitional and lacustrine characteristics. Currently, micropalaeontological analysis has been conducted in samples from the southern margin of the Corinth Gulf (Rion and Corinth Basin), and from Kefalonia and Lesvos islands. Ostracods belonging to 17 different families have been identified (Candonidae, Cushmanideidae, Cyprididae, Cytherellidae, Cytherideidae, Cytheruridae, Darwinulidae, Eucytheridae, Hemicytheridae, Leptocytheridae, Limnocytheridae, Loxoconchinidae, Neocytherideidae, Paradoxostomatidae, Pontocyprididae, Trachyleberididae,, Xestoleberididae) and characteristic SEM photos are presented herein. Future perspectives Represenative Pleistocene sedimentary successions from marine, transitional and lacustrine palaeoenvironments will be selected and sampled in order to acquire robust information about the Pleistocene ostracods of central and Southern Greece. Samples from Crete and Cyprus are already under study while two other Pleistocene sites (Elis and Megalopolis) have already been planned for sampling. This project will produce a digital collection with characteristic SEM photos of the identified ostracod species and respective information about their systematics, their ecology and distribution. A catalog with the bibliography on Greek Pleistocene ostracods will also be included. This collection intends to promote the communication between specialists and will greatly facilitate future research in the study of Pleistocene palaeoenvironments. At the same time, the gathering of published literature and the new data that will emerge will allow a future comparison of the Pleistocene ostracod species of central and southern Greece with the European Pleistocene ostracod record in order to ascertain possible relationships.

ABSTRACT. The paleontological wealth of the island of Samos, Greece had sparked the interest of researchers since the middle of the 19th century (Solounias, 1981; Koufos, 2009). The diverse fauna of this renowned Late Miocene locality is characterized by the notable presence of the hornless rhinocerotid Chilotherium (Ringström, 1924), along with the two-horned species Dihoplus pikermiensis (Toula, 1906) and “Diceros” neumayri (Osborn, 1900). In this preliminary report, we examine and evaluate for the first time previously undescribed specimens of the hornless rhinocerotid Chilotherium excavated during the first decade of the 1900s by Prof. Theodore Skoufos in Samos, which are stored at the collections of the Museum of Palaeontology and Geology in Athens (AMPG). The presence of two different two-horned rhinocerotids on Samos has been known since their first dedicated study by Weber (1904). “Diceros” neumayri, is a common element of the Late Miocene mammal faunas of the Eastern Mediterranean, and it is the dominant tandem-horned rhinocerotid on Samos Island. The frequently sympatric Dihoplus pikermiensis is also present in Samos fauna, but in a significant lower percentage (Giaourtsakis, 2009). Weber (1905) was also the first author to recognize the presence of hornless rhinocerotids (subfamily Aceratheriinae) in the fauna of Samos, which he assigned to two different new species, Aceratherium schlosseri and Aceratherium samium. Andree (1920) named two additional hornless species based on material from Samos, Aceratherium wegneri and Aceratherium angustifrons. Ringström (1924) included all aforementioned hornless species into his newly erected genus Chilotherium. Later, Heissig (1975) merged C. wegneri with C. schlosseri, and attributed C. angustifrons to C. kowalevskii (Pavlow, 1913). Recently, Giaourtsakis (2009) suggested that both C. wegneri and C. angustifrons might be junior synonyms of C. schlosseri, thus recognizing the presence of only two hornless species in Samos, C. schlosseri and C. samium. Since the current nomenclatural status of the Eastern Mediterranean chilotheres and their systematic affinities remain unsettled, we have preliminary limited our specimens’ assignment at generic level. Among the most impressive specimens of the AMPG collection is a well-preserved Chilotherium cranium with associated mandible, currently under preparation. The cranium, which is missing the nasals and the occipital region, is characterized by the following salient features: the flattened and hornless frontals, the retracted nasal notch that terminates above the mesial half of the P4, the highly placed orbital fossa with a rostral margin located above the M1, and the very short distance between the orbit and the nasal notch. On the contrary, the crania of the sympatric horned species Dihoplus pikermiensis and “Diceros” neumayri are characterized by the presence of a frontal horn boss, the markedly less retracted nasal notch, the relatively lower placed orbits, and the longer distance between the orbit and the nasal notch (Geraads, 1988; Giaourtsakis, 2009). Another interesting specimen of the AMPG collection is a partial mandible missing the ascending rami and the caudal half of the mandibular body, but preserving the symphysis. It belongs to a female individual, as deduced by the relatively small size of the second lower incisors, which are partially preserved. The mandibular symphysis is notably widened, demonstrating one of the most prominent apomorphic features of the genus Chilotherium. It is also characterized by a rather long diastema with a marked crest along the interalveolar margin, and a concave ventral profile. The mandible of Dihoplus pikermiensis is characterized by a narrower symphyseal region, featuring significantly smaller second lower incisors (Giaourtsakis et al., 2006). The symphyseal region of “Diceros” neumayri is abbreviated, and permanent second lower incisors are missing (Giaourtsakis, 2009). The postcranial material of the AMPG collection is of particular interest, as it includes several partially associated specimens that are presently under preparation. The postcranial elements of Chilotherium can be readily distinguished from the ones of the sympatric horned species, since they have significantly smaller size and relatively more robust proportions. The biogeographical and paleoecological implications of the rhinocerotid dispersal during the Late Miocene in Greece are of particular interest. The hornless genera Chilotherium and Acerorhinus migrated into Greece from Central Asia through Anatolia, at the beginning of the Vallesian (Heissig, 1975; Giaourtsakis, 2003). The Vallesian locality of Pentalophos-1 is the only Greek site where both Acerorhinus and Chilotherium are found sympatric, along with the horned rhinocerotid “Diceros” neumayri (Geraads & Koufos, 1990; Athanassiou et al., 2014). The Greek Turolian localities have yielded only one of the two hornless genera, thus far. Furthermore, in Turolian localities where both of the horned taxa Dihoplus pikermiensis and “Diceros” neumayri co-occur, one of them is usually more abundant, signifying a clear interspecific dominance (Giaourtsakis et al., 2006; Giaourtsakis, 2009). In Samos, “Diceros” neumayri is the dominant horned species, Dihoplus pikermiensis is rare, and hornless Chilotherium is present. On the contrary, in the locality of Pikermi, Dihoplus pikermiensis emerges as the dominant horned species, “Diceros” neumayri is less frequent, whereas Acerorhinus is the sole hornless rhinocerotid taxon present. These marked differences observed in the relative distribution and abundance of rhinocerotid taxa among the Turolian localities of Greece and adjacent regions appear to have been primarily influenced by environmentally controlled provincial differences. The relatively slender and brachydont Acerorhinus and Dihoplus pikermiensis seem to have preferred more closed and temperate niches, whereas the more robust and specialized “Diceros” neumayri and Chilotherium favoured more open and dry habitats. In cases of sympatry, a potential resource partitioning with limited dietary competition has been suggested (Giaourtsakis et al., 2006; Giaourtsakis, 2009; Athanassiou et al., 2014). Acknowledgements For fascilitating access to comparative material, we kindly acknowledge G. Theodorou, V. Karakitsios (Athens Museum of Palaeontology and Geology, AMPG); G. Koufos, D. Kostopoulos (Laboratory of Geology and Palaeontology, Aristotle University, Thessaloniki); P. Tassy (Muséum National d‘Histoire Naturelle, Paris); K. Heissig, G. Rössner (Bayerische Staatssammlung für Paläontologie und Geologie, München); J. Hooker, (Natural History Museum, London); G. Höck, U. Göhlich,(Naturhistorisches Museum, Wien). Financial support for comparative studies was provided to I.G. by the European Commission’s Research Infrastructure Action (under EU-SYNTHESYS grants GB-TAF 574, FR-TAF 1226, FR-TAF 2545, AU-TAF 5710). References Andree, J., 1921. Rhinocerotiden aus dem Unterpliozän von Samos. Paläontologische Zeitschrift, 20, 189-212. Athanassiou, A., Roussiakis, S. J., Giaourtsakis, I. X., Theodorou, G. E., Iliopoulos, G., 2014. A new hornless rhinoceros of the genus Acerorhinus (Perissodactyla, Rhinocerotidae) from the Upper Miocene of Kerassia (Euboea, Greece), with a revision of related forms. Palaeontographica, Abt. A: Palaeozoology - Stratigraphy 303 (1-3), 23-59. Geraads, D., 1988. Révision des Rhinocerotinae (Mammalia) du Turolien de Pikermi. Comparaison avec les formes voisines. Annales de Paléontologie 74, 13-41. Geraads, D., Koufos, G., 1990. Upper Miocene Rhinocerotidae (Mammalia) from Pentalophos-1, Macedonia, Greece. Palaeontographica, Abt. A: Palaeozoology – Stratigraphy 210, 151– 168. Giaourtsakis, I.X., 2003. Late Neogene Rhinocerotidae of Greece: distribution, diversity and stratigraphical range. Deinsea 10, 235-253. Giaourtsakis, I.X., 2009. The Late Miocene Mammal Faunas of the Mytilinii Basin, Samos Island, Greece: New Collection. 9. Rhinocerotidae. Beiträge zur Paläontologie 31, 157-187. Giaourtsakis, I., Theodorou, G. Roussiakis, S., Athanassiou, A. & Iliopoulos, G., 2006: Late Miocene horned rhinoceroses (Rhinocerotinae, Mammalia) from Kerassia (Euboea, Greece). - N. Jb. Geol. Palaont. Abh., 239: 367-398. Heissig, K., 1975. Rhinocerotidae aus dem Jungtertiär Anatoliens. Geologisches Jahrbuch (B) 15, 145-151. Koufos, G.D., 2009. The Late Miocene Mammal Faunas of the Mytilinii Basin, Samos Island, Greece: New Collection. 1. History of the Samos Fossil Mammals. Beiträge zur Paläontologie 31, 1-12. Osborn, H.F., 1900. Phylogeny of the rhinoceroses of Europe. Bulletin of the American Museum of Natural History, 12: 229–267. Pavlow, M.W., 1913. Mammifères tertiaires de la Nouvelle Russie, 1. Partie: Artiodactyla, Perissodactyla (Aceratherium kowalevskii n.s.). Nouveaux Mémoires de la Société Impériale des Naturalistes de Moscou 17, 1-68. Ringström, T., 1924. Nashörner der Hipparion-Fauna Nord-Chinas. Palaeontologia Sinica, C, 1(4), 1-156. Solounias, N. 1981. The Turolian fauna from the Island of Samos, Greece - with special emphasis on the hyaenids and the bovids. Contributions to Vertebrate Evolution 6, 1-232. Toula, F., 1906. Das Gebiss und Reste der Nasenbeine von Rhinoceros (Ceratorhinus Osborn) hundsheimensis. Abhandlungen der k.k. Geologischen Reichsanstalt, Wien 20 (2), 1-38. Weber, M., 1904. Über tertiäre Rhinocerotiden von der Insel Samos I. Bulletin de la Société Imperériale des Naturalistes de Moscou 17, 477-501. Weber, M., 1905. Über tertiäre Rhinocerotiden von der Insel Samos II. Bulletin de la Société Imperériale des Naturalistes de Moscou 18, 345-363.

ABSTRACT. The classical locality of Pikermi (Attica, Greece) is considered to be one of the most important fossiliferous localities in Europe. The fossils occur along the Megalo Rema ravine, locally known as Valanaris. The first fossils were discovered by the Scottish historian G. Finlay in 1836. Subsequently, excavations were carried out by many naturalists and palaeontologists, namely A. Lindermayer in 1843, J. Roth in 1852, H. Mitzopoulos in 1853 and 1860-1861, A. Gaudry during the winter of 1855-56 and summer of 1860, W. Dames in 1882, M. Neumayr and L. v. Tausch in 1885, A. S. Woodward and Th. Skouphos in 1901, O. Abel in 1912 and others, whereas N. Symeonidis, F. Bachmayer and H. Zapfe excavated in a nearby locality known as Kisdari or Chomateri from 1972 to 1980 (Roth & Wagner, 1854; Gaudry, 1862-67; Dames, 1883; Weithofer, 1888; Woodward, 1901; Abel, 1922; Symeonidis et al., 1973; Bachmayer et al., 1982). These excavations led to the acquisition of very important palaeontological collections of specimens from Pikermi by almost all major natural history museums of Europe (Paris, London, Athens, Munich, Berlin, Vienna etc.). The collected material has been used extensively as a reference for comparative studies in numerous publications up till now and resulted in numerous publications, including some very important ones for the early development of mammalian palaeontology (e.g. Wagner, 1839, 1840; Roth & Wagner, 1854; Gaudry, 1862-1867). Since 2008, almost two centuries after the first excavations, the National and Kapodistrian University of Athens (NKUA) resumed fieldwork in Pikermi, with a series of new systematic excavations under the direction of Prof. George Theodorou (Theodorou et al., 2010, 2013). Several new and prolific fossiliferous sites like PV1 (Fig. 1) and PV3 have been revealed. In particular, the site PV1, located about 0.5 km east of the classical site, has been thoroughly explored during the last decade. Systematic excavations have been carried out almost annually, each one lasting up to a period of three months. Until 2018, over fifty students from the Department of Geology and Geoenvironment of the NKUA, as well as other institutions, have received training or participated in the fieldwork campaigns, and more than 2000 fossil specimens have been collected. The preliminary study of the collected material from PV1 shows a rich and diverse mammalian fauna with representatives of most macromammalian groups that inhabited Greece during the Turolian. The age of the locality has been recently refined to about 7.27 Mya (Böhme et al., 2017). The most frequent mammalian representatives are hipparionine horses and bovids, but rhinocerotids and giraffids are also well represented. The faunal list includes two species of hipparionine horses, the slender Cremohipparion mediterraneum and the robust Hippotherium brachypus, the bovids Tragoportax amalthea, Gazella capricornis, Protragelaphus skouzesi, Palaeoryx pallasi and Palaeoreas lindermayeri, the cercopithecid Mesopithecus pentelicus, the felids Amphimachairodus giganteus and an unidentified felid in the size of Metailurus major, the hyaenid Adcrocuta eximia, the mustelid Promeles palaeatticus, the zygodont proboscidean “Mammut” sp., the two-horned rhinocerotids “Diceros” neumayri and Dihoplus pikermiensis, the giraffids Bohlinia attica, Palaeotragus rouenii and Helladotherium duvernoyi, the suid Hippopotamodon erymanthius and the rodent Hystrix primigenia. Complementing the list of mammalian taxa is a relatively smaller number of representatives of the class Aves, including Pavo archiaci (Phasianidae), as well as of the class Reptilia with Testudo cf. marmorum (Testudinae) and Varanus sp. (Squamata) (Theodorou et al., 2010, 2013; Roussiakis et al., 2014). Recent palaeoecological reconstructions place the aforementioned fauna in a wooded grassland-to woodland habitat of a savannah biome (Böhme et al., 2017), supporting the initial environmental interpretations put forward by A. Gaudry (1862-1867). Pikermi is one of most significant Late Miocene localities in Europe. The detailed study of the newly excavated material is essential for improving the understanding of the taphonomical, biogeographical and palaeoecological context of the locality, as well as for the evaluation of the systematic affinities and phylogenetic position of the Pikermian taxa. In particular, one of the key objectives based on this stratigraphically well-calibrated material is the assessment of the potential existence of multiple stratigraphic levels, as opposed to the commonly regarded biochronological and taxonomic homogeneity of the Pikermian fauna (Theodorou & Nicolaides, 1988). Currently, a preliminary exhibition featuring specimens from the new excavations and selected reconstructions is housed in the Rafina-Pikermi Municipality’s Urban Planning Building (Fig. 1). This exhibition has achieved to generate public interest and awareness on the scientific significance of the locality, through numerous visits by schools and non-profit organizations. Imminent plans of the project include the annual continuation of the excavations, with an expansion to other sites including PV3 and Chomateri, as well as the thorough preparation of the material and its scientific evaluation. The primary objectives encompass the establishment of a multidisciplinary and educational protected Geopark at Pikermi, as well as the founding of a local Palaeontological Museum, where the material of the excavations and a new permanent exhibition shall be housed.

References: Abel, O., 1922. Lebensbilder aus der Tierwelt der Vorzeit. Jena, 644 p. Bachmayer, F., Symeonidis, N., Zapfe, H., 1982. Die Ausgrabungen in Pikermi-Chomateri bei Athen. Eine Dokumentation. Annalen des Naturhistorischen Museums in Wien 84, 7-12. Böhme, M., Spassov, N., Ebner, M., Geraads, D., Hristova, L., Kirscher, U., et al., 2017. Messinian age and savannah environment of the possible hominin Graecopithecus from Europe. PLoS ONE 12 (5), e0177347. Gaudry, A., 1862-1867. Animaux fossiles et géologie de l’Attique. F. Savy, Paris, 475 p. Dames, W., 1883. Hirsche und Mäuse von Pikermi in Attica. Zeitschrift der Deutschen Geologischen Gesellschaft 35 (1), 92-100. Roth, J., Wagner, A., 1854. Die fossilen Knochenüberreste von Pikermi in Griechenland. Abhandlungen der Bayerischen Akademie der Wissenschaften 7 (2), 371-464. Roussiakis, S., Athanassiou, A., Michailidis, D., Mitsopoulou, V., Solomos, Ch., Theodorou, G., 2014. Remarks on new proboscidean remains from the classical Late Miocene locality of Pikermi and their associated fauna. Scientific Annals, School of Geology, Aristotle University of Thessaloniki, Greece, VIth International Conference on Mammoths and their Relatives, Grevena - Siatista 102, 171-172. Symeonidis, N., Bachmayer, F., Zapfe, H., 1973. Ausgrabungen in Pikermi bei Athen, Griechenland. Annalen des Naturhistorischen Museums in Wien 77, 125-132. Theodorou, G., Nicolaides, S., 1988. Stratigraphic horizons at the classic mammal locality of Pikermi, Attica, Greece. Modern Geology 13, 177-181. Theodorou, G., Roussiakis S., Athanassiou, A., Filippidi A., 2010. Mammalian remains from a new site near the classical locality of Pikermi (Attica, Greece). Scientific Annals, School of Geology, Aristotle University of Thessaloniki 99, 109-119. Theodorou, G., Roussiakis, S., Athanassiou, A., Mitsopoulou, V., Solomos, Ch., Lychounas, A., 2013. Pikermi; new excavations at a classical locality. 14th R.C.M.N.S. Congress “Neogene to Quaternary Geological Evolution of Mediterranean, Paratethys and Black Sea”, Istanbul, Turkey, Abstracts, p. 128. Wagner, A., 1839. Fossile Ueberreste von einem Affenschädel und andern Saügthieren aus Griechenland. Gelehrte Anzeigen 8, 305-311. Wagner, A., 1840. Fossile Ueberreste von einem Affen und einigen andern Säugthieren aus Griechenland. Abhandlungen der Bayerischen Akademie der Wissenschaften 2Kl. 3 (1), 155-170. Weithofer, A., 1888. Beiträge zur Kenntniss der Fauna von Pikermi bei Athen. Beiträge zur Paläontologie Österreich-Ungarns und des Orients 6, 225-292. Woodward, A. S., 1901. On the bone beds of Pikermi, Attica and on similar deposits in Northern Euboea. Geological Magazine 8, 481-486.

ABSTRACT. Introduction Hereby, we present the first high resolution palaeoenvironmental record of the last 300 years from the area of Attica, South Greece. The very recent environmental changes and the imprint of human activity in marine palaeoenvironmental records are still poorly understood, despite the increasing number of archives from Greece during the last decades (e.g. Kouli et al., 2012; Gogou et al., 2016; and references therein). Objectives Through the study of alkenone paleothermometry and a plethora of geochemical, micropaleontological and pollen proxy-indices obtained from the marine multi-core WFS2, we aim to provide insights into the prevailing environmental and climatic dynamics in this region i.e. variabilities in temperature, salinity, humidity vs. aridity, redox conditions, changes in marine productivity and land vegetation patterns throughout the last 300 years, as also as the development of the anthropogenic signal (i.e. inputs of fossil fuel hydrocarbons and their combustion-derived compounds) after the Industrial Revolution Era. Methodology The multi-core was sampled at 0.5 cm resolution and the sediment samples have been stored at -20ºC. 52 dried samples were extracted with mixture of organic solvents and analyzed by column chromatography and gas chromatography coupled to mass spectrometry for the determination of lipid biomarkers, namely n-alkanes, n-alkanols, sterols, alkenones, diols and keto-ols, fatty acids. For the reconstruction of past Sea Surface Temperatures (SSTs) the alkenone unsaturation index (Uk'37) was calculated according to Gogou et al. (2016). Land plant wax n-alkanes (Ter n-alkanes) as well as steroidal alcohols (sterols) were used as proxies (Gogou et al., 2007) to track ecosystemic and environmental changes in the terrestrial and marine realm. The productivity from Prymnesiophyte and other nannoplankton algal species is reflected by the abundance of long-chain alkenones and diols/ keto-ols, respectively (Marlowe et al.,1984). The Unresolved Complex Mixture (UCM) of aliphatic hydrocarbons, a commonly observed persistent contaminant mixture in marine sediments consisting of branched alicyclic hydrocarbons (Gough and Rowland, 1990), is used as an indicator of the contribution from anthropogenic activities i.e. chronic oil pollution (Wang et al., 1999). The Carbon Preference Index of long chain n-alkanes (CPINA) has been used as indicator of terrestrial organic matter supply with CPI values in fresh leaves being typically >4 (Collister et al., 1994), while fossil fuel n-alkanes present CPINA values ~1 (Wang et al., 1999). 50 samples were prepared and analyzed for stable isotopic composition of C and N (δ13C and δ15Ν). Pollen analysis was performed on 46 samples. Pretreatment followed classical palynological protocol including spiking and sieving through a 10 μm mesh. Pollen concentrations were calculated based on the known amount of “exotic” spores added and is expressed as grains or cysts per gram of dry sediment. Percentage and concentration pollen diagrams were constructed using TILIA Graph software. The PDI (Pollen Disturbance Index: Kouli, 2015) sum includes selected anthropogenic indicators (e.g. Centaurea, Cichorieae, Plantago, Pteridium, Sarcopoterium) and is used to explore pastoral activities in the borderlands of Elefsis Bay. Results & Discussion The alkenone-derived SSTs at Elefsis Bay drop by almost 1oC from the end of the 17th to the beginning of the 18th century. This cooling is probably synchronous to one of the coldest intervals (ad 1645–1715) of the ‘Little Ice Age’ (LIA), characterized by a prolonged episode of volcanic and low solar activity known as ‘Maunder minimum’ (MM) (Xoplaki et al., 2005). After that and throughout the 18th century, SSTs stabilize at a mean temperature of 23oC. During the 19th century a gradual increase of SSTs is observed. After the last decades of the 19th century (marking the beginning of the Industrial Era in Greece) the SST turns back to an increasing mode. The trend of the SST values shows a decrease during the 20th century, possibly reflecting the result of a combination of events that have thereafter affected the temperature and other physicochemical characteristics of the study area. The significant population rise and the related urban activities in the Athens metropolitan area during the second half of the 19th century resulted to a noticeable decrease of CPI, and a radical increase of UCM, attributed to enhanced terrestrial inputs (Ter n-alkanes) thus marking the entrance to the Industrial Era. During the same interval, an increase in the abundance of alkenones and of specific sterols, reflects the higher productivity from algal species linked to enhanced continental inputs and consequently increased nutrient supply to the coastal environment. Pollen assemblages indicate the existence of a diverse Mediterranean plant landscape, while prominent is the imprint of the human activities on the vegetation. Evergreen Quercus, accompanied by Pistacia and Phillyrea, are the most conspicuous taxa featuring the occurrence of Mediterranean macchia. Thermophilous deciduous oaks woodlands compose a significant part of the vegetation, especially at the lower part of our record. Mountainous forest is underlined by the presence of Abies, while a big variety of herb taxa fill in the landscape. Olea is a major component of the vegetation throughout the entire record. Olive cultivation is intensified after the first quarter of the 18th century and seems to be one of the major human activities in the area. Anthropogenic indicator pollen implies the decrease of pastoral activities during the 19th century and since the end of the 20th century. During the 19th and most of the 20th century the impact of grazing activities on vegetation is more pronounced. A very distinct transitory drop in human indicators is recorded in mid- 18th century. This temporal retreat in olive cultivation and grazing activities can be connected with the societal instability during the Greek War of Independence. Finally since the last quarter of the 19th century and until the mid 20th century a gradual retreat of Pinus is recorded, probably associated with the start of the Industrial Period in Greece and the increased requirement for fuel like firewood. Conclusions Our study revealed marine and terrestrial environmental and ecosystem responses to climatic variability along with land-ocean interactions in the Elefsis Bay, South Greece, during the last 300 years. Distributions of the lipid markers indicated the impact of both marine and terrestrially derived organic matter inputs in the study area, which were highly intensified after the onset of the Industrial Era in Greece. Vegetation patterns denote the significant role of human activities in shaping the landscape of the Elefsis region

ABSTRACT. INTRODUCTION During the Late Cenozoic (Tertiary, Quaternary) the Western Palearctic region experienced a number of climatic changes (e.g., Ice Ages), geotectonic changes (e.g., final rise of the Alpes; extension and formation of sedimentary basins) as well as more complex events (e.g., Messinian salinity crisis; changes in sea level; Middle Miocene climatic Optimum). These events had a significant impact on the evolution of flora and fauna in this region during those periods. Ectothermic reptiles, such as turtles, are more susceptible to these changes and can be used as palaeoecological indicators. Also, and mainly due to the presence of their carapace, turtles have an excellent fossil record which provides the ability of exporting considerable inferences. Nevertheless, compared to other vertebrate groups (e.g., mammals), the turtle fossils have been rarely studied elaborately. Particularly in Europe, the fossil record of the turtles is mostly complete, from the Tertiary to the Present (e.g., Lapparent de Broin 2001; Danilov, 2005). Therefore, the study of fossilized turtles can provide insights regarding the effect of climate and environmental changes on the evolution, diversity, and anatomy of the turtles

ABSTRACT. Geochemical Distribution and Foraminiferal Analysis from a Basin in SE Aegean Sea. C. Kozanoglou1, G. Rousakis1, M. Geraga2, G. Papatheodorou2, A. Arabas3, A. Gogou1, C. Parinos1, M. Triantaphyllou4 (1) Hellenic Centre for Marine Research, Institute of Oceanography, 19013 Anavyssos, Attiki, Greece, ckozanoglou@yahoo.gr (2) Laboratory of Marine Geology and Physical Oceanography, Department of Geology, University of Patras, 26100, Rion-Patra, Greece, (3) Institute of Geological Sciences, Polish Academy of Sciences, Research Centre in Kraków, ul. Senacka 1, Kraków 31-002, Poland, (4) Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Panepistimioupolis 15784, Athens, Greece

Introduction This study concerns an area located in the basin between Tilos and Symi, near Kos and Rhodes, southeast Aegean Sea, in the SE Mediterranean (Figure 1). The Aegean Sea is distant and almost isolated from the North Atlantic oceanic circulation and is considered a key region as it reflects high and low latitude climate changes, through an intense atmospheric connection. Reconstructions of climate during the Holocene have revealed the occurrence of determining episodes of severe cooling also on multi-centennial to millennial timescales (Rohling et al., 2002; Casford et al., 2003). The study area is also near the Rhodes gyre where formation of Levantine intermediate waters occurs. Here we present high resolution measurements of organic carbon Corg, nitrogen Ntot concentrations and micropaleaontological results focusing on planktonic foraminifera during the S1 deposition. Sapropel S1, deposited during the Holocene Climate Optimum is characterized by strongly dysoxic conditions punctuated by reventilation events in the Aegean sea (e.g., Abu-Zied et al., 2008; Filippidi et al., 2016). Material and methods The chronostratigraphy of the studied core is based on accelerator mass spectroscopy (AMS) 14C dating performed on planktonic foraminiferal assemblages. Core ST5 (3.81 m long) retrieved from 688 m depth, has been photographed and visually described. Samples for organic carbon and nitrogen analysis were collected with 0.5–4 cm resolution. Samples for planktonic foraminiferal analysis were separated at a high resolution sampling interval of 0.5 cm, were disaggregated using hydrogen peroxide and then wet sieved through a 125 μm mesh. The dried material was split into aliquots using an Otto microsplitter. At least 200 specimens were picked and identified for each sample. In all, 35 samples were collected for stable isotope analyses (δ18O) using the tests of the handpicked planktonic foraminifera Globigerinoides ruber. Results and Discussion The core ST5 contains a dark color mud that corresponds to sapropel S1 consisting of two discrete layers, the lower layer S1a and the upper layer S1b which are separated by the lighter-colored S1 interruption. The organic carbon values downcore fluctuate and suggest that subtle changes actually occur during the deposition period. The lower part (S1a) and the upper part of the sapropel (S1b) have similar Corg average concentrations (1.2%) while the interruption interval has an average Corg=0.7%. High organic carbon content in sapropels shows an increase in primary productivity due to enhanced nutrient availability. The ratio Corg/Ntot in S1a, S1b and Si is respectively 11.6, 10.3 and 9.7. Above S1 we calculated a Corg/Ntot=9.3 and below S1 the ratio increased to 9.9. The difference in Corg/Ntot ratios between sapropels and background sediments could indicate changes in the source of organic matter: algal or land-plant derived organic matter (Arnaboldi et al., 2006; Gogou et al., 2007). The study includes qualitative and quantitative analysis of planktonic foraminifera as the composition of their assemblages reflects water mass conditions (e.g., Casford et al., 2003). The benthic foraminifera are very good indicators of conditions prevailing in the sea bottom (dysoxic /anoxic) and the water masses circulation. In each sample we determined the abundances and some key benthic foraminifera groups. The determined planktonic foraminiferal assemblages are composed mostly of Globigerinoides ruber (alba and rosea), Globigerina bulloides, G. falconensis, Globigerinella calida, G. siphonifera, Globigerinita glutinata, G. uvula, Globigerinoides conglobatus, G. sacculifer, G. trilobus, Globorotalia inflata, Gl. truncatulinoides,Globoturborotalita rubescens, Hastigerina, Neogloboquadrina incompta, N. dutertrei, N. pachyderma, Orbulina universa, Turborotalita quinqueloba. The species belonging to the SPRUDTS group (Rohling et al., 1997) and G. ruber (alba and rosea) dominate warm and oligotrophic summer mixed layers in subtropical regions and the eastern Mediterranean and consequently the downcore variation of their percentages is considered an indicator of SST variability (Pujol et al., 1995; Triantaphyllou et al., 2016). The warm planktonic foraminifera group ranges from 41 to 65% during the S1a deposition, while it varies in-between 54 and 89% within the S1b deposition interval. Above the sapropel the planktonic foraminifera abundance pattern reveals at least two distinct episodes of successive increased and decreased warm water species abundances. This observation due to a high resolution analysis may capture and reveal more detailed information for climatic changes in the area and consequently needs further investigation compiled with the δO18 measurements on Globigerinoides ruber tests.

Figure 1. Conventional bathymetry of the Nisyros – Tilos – Symi – Chalki region and location of the studied core.

Acknowledgements The authors sincerely acknowledge Dr. V. Lycousis for his precious and constructive scientific support.

References Rohling, E.J., Jorissen, F.J., De Stigter, H.C., 1997. 200 Year interruption of Holocene sapropel formation in the Adriatic Sea. J. Micropalaeontol. 16, 97–108. Rohling, E.J., Mayewski, P.A., Hayes, A., Abu-Zied, R.H., Casford, J.S.L., 2002. Holocene atmosphere-ocean interactions: records from Greenland and the Aegean Sea. Clim. Dyn. 18, 587–593. Casford, J.S.L., Rohling, E.J., Abu-Zied, R.H., Jorissen, F.J., Leng, M., Thomson, J., 2003. A dynamic concept for eastern Mediterranean circulation and oxygenation during sapropel formation. Palaeogeogr. Palaeoclimatol. Palaeoecol. 190, 103–119. Abu-Zied, R.H., Rohling, E., Jorissen, F.J., Fontanier, C., Casford, J.S.L., Cooke, S., 2008. Benthic foraminiferal response to changes in bottom-water oxygenation and organic carbon flux in the eastern Mediterranean during LGM to Recent times. Mar. Micropaleontol. 67, 46–68 Arnaboldi, M., Meyers, P.A., 2006. Patterns of carbon and nitrogen stable isotopic compositions of latest Pliocene sapropels from six locations across the Mediterranean. Palaeogeog. Palaeoclimatol. Palaeoecol. 235, 149–167. Filippidi, A., De Lange, G, Triantaphyllou, M.V., 2016… Gogou, A., Bouloubassi, I., Lykousis, V., Arnaboldi, M., Gaitani, P., Meyers, P.A., 2007. Organic geochemical evidence of abrupt late glacial-Holocene climate changes in the North Aegean Sea. Palaeogeogr. Palaeoclimatol. Palaeoecol. 256, 1–20 Pujol, C., Vergnaud-Grazzini, C., 1995. Distribution of live planktic foraminifers as related to regional hydrography and productive systems of the Mediterranean Sea. Mar. Micropaleontol. 25, 187–217 Triantaphyllou, M.V., Gogou, A., Dimiza, M.D., Kostopoulou, S., Parinos, C., Roussakis, G., Geraga, M., Bouloubassi, I., Fleitmann, D., Zervakis, V., Velaoras, D., Diamantopoulou, A., Sampatakaki, A., Lykousis, V., 2016. Holocene climatic optimum centennial-scale paleoceanography in the NE Aegean (Mediterranean Sea). Geo-Mar. Lett. 36, 51-66.

ABSTRACT. Introduction Fossil associations are an essential tool for studying past sea-level changes in coastal areas (e.g. Pallikarakis et al., 2018). The Corinth Isthmus located at the eastern part of Corinth Gulf is influenced both by glacioeustatic sea level changes and tectonic movements, resulting into a complex lithostratigraphic pattern (e.g. Freyberg, 1973; Collier, 1990; Pallikarakis et al., 2018). The study area is controlled by major fault structures such as the South Alkyonides fault zone, the Loutraki, the Agios Vassileios and the Kenchreai faults and by shorter local faults, like the Kalamaki–Isthmia fault (e.g. Roberts et al., 2009; Papanikolaou et al., 2015). As a result the Corinth Isthmus is constantly uplifted 0.3 mm/yr during at least the last 200 ka (Collier et al., 1992; Dia et al., 1997). The sedimentary facies in Corinth Isthmus consists of marls, sandstones and conglomerates representing offshore, shoreface and coastal paleoenvironments, organized in six transgressive-regressive cycles ranging from marine isotope stages 11 to 5 (e.g. Freyberg, 1973; Collier, 1990; Pallikarakis et al., 2018). Materials and Methods An approximately 70 m deep borehole core (Bh-3) extracted at 19.20 m above the present sea level, is characterized by lithological alternations of clay, marl clayey sand, sand, sandstone, conglomerate and soil horizons reflecting low-energy to high-energy depositional environments. Fifty five samples extracted from the sedimentary sequence have been analyzed for their micropaleontological content, following standard procedures (e.g. Triantaphyllou et al., 2010). Foraminiferal species have been subjected into two-way cluster analysis to highlight biofacies. Thirteen samples of fine-grained sediments were examined by Scanning Electron Microscopy (SEM) for their calcareous nannoplankton content. Furthermore magnetic susceptibility (MS) within the core was measured with the Bartington MS2 system with the MS2K sensor, where sixty one MS measurements have been carried out from various lithological alternations within the core. Results and Discussion Fourteen benthic foraminiferal taxa comprised more than 90% of the total assemblage (e.g. Ammonia spp., Elphidium spp., Discorbis spp., Asterigerinata spp., miliolids). Based on the microfossils analysis three distinctive clusters have been described as separate biofacies. Cluster I indicated shallow marine assemblage (regional estimated sea paleodepth ~40 m), Cluster ΙI indicated lagoon assemblage (regional estimated sea paleodepth ~0-20 m) and Cluster III was associated with a shallow marine assemblage with fresh water influence (regional estimated sea paleodepth ~20-40 m). The identified calcareous nannoplankton specimens were dominated by the presence of small Reticulofenestra spp. (~40%) and small Gephyrocapsa spp. (~30%) coccoliths, while Emiliania huxleyi species was relatively scarce (5-8% of the total assemblage), but consistently present. Furthermore the magnetic susceptibility in Bh-3 sediments ranged from 1 to 207 ×10-5 (SI units), where clayey and fine coarse sediments displayed lower MS signal than gravely and coarse sediments. Based on the lithological, microfaunal and MS analysis, the paleoenvironment and the palaeobathymetry within the borehole were interpreted, describing successions of lagoonal to shallow marine deposits (highstand) with terrestrial deposits (lowstand). Within the borehole core five successive sedimentary sequences have been defined, indicating the onset of transgressive-regressive (T-R) conditions. Correlating the glacioeustatic sea level change curve of Siddall et al. (2003) with the uplift rate 0.3 mm/yr for the Corinth Isthmus area (e.g. Collier et al., 1992; Dia et al., 1997), it appears that marine deposits would have been expected to be preserved during the high stands within MIS 5.5, 6.5, MIS 7 and MIS 9 with maximum depths ranging between ~20 and 80 m (e.g. Siddall et al., 2003), while the study area is expected to be emerged above sea level during MIS 2.21, MIS 6.0 and MIS 7.0. Transgressive stacking patterns therefore, would have been expected to be deposited during the high stands MIS 5.5, 6.5, 7, 9. The continuous existence of E. huxleyi throughout the borehole core indicates that depositional ages are younger than 265 ka (e.g., Raffi et al., 2006), limiting the marine sedimentation to MIS 5.5, MIS 6.5 and MIS 7 high stands. Three possible scenarios can describe the sedimentation processes. In the first scenario, the entire sequence can be associated with the MIS 7 highstand, where marine sedimentation processes are interrupted by terrestrial sediments due to relative sea level fluctuations associated with the sub-stages MIS 7.1, 7.3, 7.4 and 7.5. In the second scenario the described sediments are correlated with MIS 5.5 and MIS 7, while the third scenario involves sedimentation in all three possible MIS periods (MIS5.5, MIS 6.5 and MIS 7). Scenarios 2 and 3 are relatively similar and can be distinguished only by absolute dating data. The third scenario is considered as the most favorable to describe the sedimentation processes based on the described sea water paleodepths within the core (Pallikarakis et al., 2018) and the modeled shoreline elevations described in Papanikolaou et al. (2015). Conclusions Through multi-proxy analysis of the borehole core the paleoenvironment has been described, where based on two way cluster analysis of the foraminiferal assemblages three distinct biofacies were described, Cluster I (shallow marine), Cluster II (lagoonal) and Cluster III (transition from lagoon to shallow marine conditions). The presence of E. huxleyi (NN21a biozone), indicates that Bh-3 sediments are younger than MIS 8. Based on the glacioeustatic sea level changes, along with the measured uplift rate of the area, MIS 7, MIS 5.5 and possible MIS 6.5 highstands are described in the eastern part of the Corinth Isthmus. Acknowledgements The Academy of Athens scholarship (Mitsopoulos Fund) is thanked for financial support. References Collier, R.E.L., 1990. Eustatic and tectonic controls upon Quaternary coastal sedimentation in the Corinth Basin, Greece. Journal of the Geological Society, 147, 301-314. Collier, R.E.L.; Leeder, R.M.; Rowe, P., Atkinson, T., 1992. Rates of tectonic uplift in the Corinth and Megara basins, Central Greece. Tectonics, 11(6), 1159-1167. Dia, A.N.; Cohen, A.S.; O'Nions, R.K., Jackson, J.A., 1997. Rates of uplift investigated through 230Th dating in the Gulf of Corinth (Greece). Chemical Geology, 138(3-4), 171-184. Freyberg, V., 1973. Geologie des Isthmus von Korinth, Erlangen Geologische Ablhandlungen, Heft 95. Junge und Sohn, Universitats Buchdruckerei Erlangen,183p. Pallikarakis, A., Triantaphyllou, M., Papanikolaou, I., Dimiza, M., Reicherter, K., Migiros, G., 2018. Age Constraints and Paleoenvironmental Interpretation of a Borehole Sedimentary Sequence at the Eastern Part of Corinth Isthmus, Greece. Journal of Coastal research, 34,3 Papanikolaou I.D.; Triantaphyllou, M.; Pallikarakis A., Migiros, G., 2015. Active faulting at the Corinth Canal based on surface observations, borehole data and paleoenvironmental interpretations. Passive rupture during the 1981 earthquake sequence?. Geomorphology, 237, 65-78 Raffi, I.; Backman, J.; Fornaciari, E.; Palike, H.; Rio, D.; Lourens, L., Hilgen, F., 2006. A review of calcareous nannofossil astrobiochronology encompassing the past 25 million years. Quaternary Science Reviews, 25(23), 3113–3137. Roberts, G.P.; Houghton, S.L.; Underwood, C.; Papanikolaou, I.; Cowie, P.A.; van Calsteren, P.; Wigley, T.; Cooper, F.J., McArthur, J.M., 2009. Localization of Quaternary slip rates in an active rift in 105 years: an example from central Greece constrained by 234U-230Th coral dates from uplifted paleoshorelines. Journal of Geophysical Research, 114(B104). Doi:org/10.1029/2008JB0058. Siddall, M.; Rohling, E.J.; Almogi-Labin, A.; Hemleben, Ch.; Meischner, D.; Schmelzer, I., Smeed, D.A., 2003. Sea-level fluctuations during the last glacial cycle. Nature, 423, 853-858. Triantaphyllou, M.V.; Kouli, K.; Tsourou, T.; Koukousioura, O.; Pavlopoulos, K., Dermitzakis, M.D., 2010. Paleoenvironmental changes since 3000 BC in the coastal marsh of Vravron (Attica, SE Greece). Quaternary International, 216(1-2), 14-22.

ABSTRACT. Background Coccolithophores constitute a significant component of the phytoplankton communities in the oligotrophic environments of the Aegean Sea, especially in the south Aegean (Ignatiades et al., 2002; Triantaphyllou et al., 2004). In particular, Emiliania huxleyi is a key taxon for the coccolithophore productivity in the marine environment of Aegean Sea, but also numerous species of Syracosphaera spp., Rhabdosphaeraceae and holococcolithophores show significant contributions mainly in relatively diverse summer assemblages (e.g., Triantaphyllou et al., 2004; Malinverno et al., 2009; Dimiza et al., 2015; Karatsolis et al., 2017; Skampa et al., 2019). These studies showed that coccolithophore dynamics display a highly seasonal variability primarily driven by the local water circulation pattern, changes in temperature and nutrient availability. Despite the well-studied coccolithophore assemblages in various marine ecosystems of the Aegean Sea, little is known about the coccolithophore species composition and variability in anthropogenically impacted neritic regions. In a recent study on the late-winter coccolithophore assemblages from the industrial zone of Elefsis-Saronikos Gulf, Dimiza et al. (2014) reported significantly lower abundance and species diversity compared with off-shore assemblages of the Aegean Sea, with nearly monospecific assemblages of Helicosphaera carteri, which behaved like an opportunistic taxon. Objectives In the present study, we investigated the living coccolithophore abundance, community structure and key species of coccolithophores from a 12 monthly time series in the Thessaloniki Bay, a polluted bay located in the inner part of Thermaikos Gulf (Northwestern Aegean Sea). The aims of this research were to examine the seasonal variation of coccolithophorres and determine the effects of environmental factors on their abundance, species composition and distribution in a restricted environment with intense anthropogenic activity. Materials and methods The monitoring site is located near the outer edge of the Thessaloniki Bay (Inner Thermaikos Gulf), about 7 km south of the Thessaloniki city (station SP1: 40°35’11.72” N and 22°55’1.20” E) and is approximately 22 m in depth. Water samples have been collected by pumping, on a monthly basis between January and December 2016. During each sampling campaign, water temperature and salinity measurements were obtained with a CTD device. Monthly-averaged data for satellite chlorophyll a (Chl-a) concentration from MODIS-Aqua (MODerate resolution imaging spectroradiometer) were obtained from the National Aeronautic and Space Administration (NASA) Giovanni website (http://disc.sci.gsfc.nasa.gov/techlab/giovanni/). Phytoplankton counts (cells, colonies, and filaments) were performed on subsample volume of 25 ml of seawater per sample using a Zeiss inverted light microscope (LM) following the sedimentation method described by Utermohöl (1958). The coccolithophore composition and community structure was evaluated through Scanning Electron Microscopy. The samples were examined in a Jeol JSM 6360 Scanning Electron Microscope (SEM) (University of Athens, Faculty of Geology and Geoenvironment) and the coccospheres per liter was calculated following the methodology of Jordan and Winter (2000). Results and Discussion The sea surface temperatures exhibited a seasonal cycle with low values ~11°C in wintertime and maxima of approximately 26°C during the summer months. Sea surface salinity values (< 22.5) were low from January through to May indicating significant freshwater supply and increased gradually to 34.7 in the following months. Satellite measurements of Chl-a concentrations in this area were quite high (> 2.5 mg m-3) throughout the year with a spring peak reaching 33 mg m-3. The phytoplankton community was composed mainly of diatoms, dinoflagellates, coccolithophores, cryptophytes, silicoflagellates and euglenophytes. The total phytoplankton abundance ranged from 2 × 104 cells l-1 to 1.5 × 106 cells l-1 and averaging 3.5 × 105 cells l-1. The seasonal pattern showed a main peak in April-May and a secondary increase in October. Diatoms were the most abundant component of the phytoplankton community, whereas coccolithophores were the second significant element of the community. Dinoflagellates were abundant mostly in July. Coccolithophore assemblages were dominated mostly by Emiliania huxleyi, a typical opportunistic species; well known for its quick response to nutrient enrichment, even in oligotrophic areas (e.g., Dimiza et al., 2015). This species displayed concentrations of up to 24 × 103 coccospheres l-1 during winter-early spring, similar to the typical E. huxleyi Aegean values. However, extremely high cell densities of E. huxleyi (420 × 103 coccospheres l-1) were observed in April, following Chl-a maxima. Gephyrocapsa oceanica, a well-known species for its preference for warm, high-nutrient, less saline waters (e.g., Andruleit and Rogalla, 2002), represented a major component (210 × 103 coccospheres l-1) to coccolithophore abundance in July. Its abundance is unusually high for the coccolithophore assemblages of the Aegean Sea, where this species has been rarely reported. Helicosphaera carteri, and various species of Syracosphaera, such as S. protrudens, S. molischii represented minor components of the coccolithophore assemblages. The seasonal variation of living coccolithophores reflects the exceptional environmental conditions that prevailed in the semi-closed inner Thermaikos Gulf with respect to the open Aegean Sea, thus providing further evidence of the species’ biogeography. Acknowledgments Financial support for this study was provided by Municipality of Thessaloniki. References Andruleit, H., Rogalla, U., 2002. Coccolithophores in surface sediment of Arabian Sea in relation to environmental gradients in surface waters. Marine Geology, 186, 505–526. Dimiza M.D., Triantaphyllou M.V., Malinverno E., 2014. New evidence for the ecology of Helicosphaera carteri in polluted coastal environments (Elefsis Bay, Saronikos, Greece). Journal of Nannoplankton Research, 34: 37–43. Dimiza, M., Triantaphyllou, M.V., Malinverno, E., Psarra, S., Karatsolis, BT., Mara, P., Lagaria, A., Gogou, A., 2015. The composition and distribution of living coccolithophores in the Aegean Sea (NE Mediterranean). Micropaleontology 61, 521–540. Ignatiades, L., Psarra, S., Zervakis, V., Pagou, K., Souvermezoglou, E., Assimakopoulou, G., Gotsis-Skretas, O., 2002. Phytoplank ton size-based dynamics in the Aegean Sea (Eastern Mediterranean). J. Mar. Sys., 36, 11–28. Jordan, R.W., Winter, A., 2000. Assemblages of coccolithophorids and other living microplankton off the coast of Puerto Rico during January-May 1995. Mar. Micropaleontol. 39, 113–130. Karatsolis, B.-Th., Triantaphyllou, M.V., Dimiza, M. D., Malinverno, E., Lagaria, A., Mara, P., Archontikis, O., Psarra, S., 2017. Coccolithophore assemblage response to Black Sea Water inflow into the North Aegean Sea (NE Mediterranean). Continental Shelf Research 149, 138–150. Malinverno, E, Triantaphyllou, M.V., Stavrakakis, S., Ziveri, P., Lykousis, V., 2009. Seasonal and spatial variability of coccolithophore export production at the South-Western margin of Crete (Eastern Mediterranean). Marine Micropaleontology 7, 131–147. Skampa, E., Triantaphyllou, M.V., Dimiza, M.D., Gogou, A., Malinverno, E., Parinos, C., Panagiotopoulos, I.P., Baumann, K.-H., 2019. Coupling plankton-sediment trap-surface sediment coccolithophore regime in the North Aegean Sea (NE Mediterranean). Marine Micropaleontology, https://doi.org/10.1016/j.marmicro.2019.03.001. Triantaphyllou, M.V., Ziveri, P., Tselepides, A., 2004. Coccolithophore export production and response to seasonal surface water variability in the oligotrophic Cretan Sea (NE Mediterranean). Micropaleontology 50, 127–144. Utermöhl, H., 1958. Zur Vervollkommnung der quantitativen Phytoplankton. Methodik. Mit. lnt. Verein. Theor.Angew. Limnology, 9, 1-38.

ABSTRACT. During the last decades, a great number of studies have been conducted in the Holocene coastal plains of the Aegean Sea, using multi-proxy approaches. In particular, the combination of benthic foraminiferal, palynological and molluscan analysis, along with stratigraphical, sedimentological, magnetic susceptibility and radiocarbon dating techniques, have been proven to be an invaluable tool box for such researches (e.g., Pavlopoulos et al. 2010; Theodorakopoulou et al., 2009; Triantaphyllou et al. 2010, 2016; Vouvalidis et al., 2010). However, limited information is available for the north coastal zone of Greece (Karadimou et al., 2016; Koukousioura et al., 2012; Pavlopoulos, 2010). Lake Ismarida, known also by Herodotus description, is located in the lowlands of Thrace near the north Aegean coast. Therefore, it is a valuable archive for reconstructing palaeoenvironmental changes in the area. The lake is placed 20 Km south of Komotini city (Thrace, N. Greece), in the western side of Filiouris River valley, bordered on the west by Neogene sediments and on the east by the alluvial sediments of the Filiouris plain. The ISMR-2 5.8-m long sediment core was retrieved from Lake Ismarida area, in order to reconstruct the paleoenvironments and paleovegetation since mid-Holocene. Systematic stratigraphic, sedimentological, and paleontological analyses were performed, while the magnetic susceptibility of the recovered deposits was measured. More than 50 samples were used for combined micropaleontological and palynological analysis and 190 for mollusc analysis (Karadimou et al., 2016). Furthermore, four horizons were radiometrically dated with AMS 14C. The analysis of paleontological, stratigraphical, sedimentological and magnetic susceptibility data as well as the evaluation of 14C datings, revealed four well-distinguished evolutionary phases in the mid-Holocene Ismarida Lake succession: (i) from ~5500 to ~3500 cal BP silty sand with coarse sand horizons was deposited bearing mainly marine foraminiferal and mollusc species and high abundances of marine dinoflagellate cysts. Magnetic susceptibility values were low (Fig. 1), confirming a shallow marine environment in accordance with fauna and flora findings (ii) between ~3500 and 3000 cal BP the distinct lagoon features recorded are indicating the isolation of the area. Nevertheless, the communication with the sea is still evident in both fauna and flora. Benthic foraminiferal assemblage is characterized by a mixture of mainly marine but also some euryhaline species, while macrofauna and flora present a similar composition. The low magnetic susceptibility values agree with an open lagoonal environment, in good communication to the sea (iii) subsequently the isolation of the core area took place with the establishment of an inner lagoon with limited communication to the sea, until ~2000 cal BP. The overall aquatic palynomorph and mollusk assemblages reflect a complex depositional environment with both marine and fresh water inputs. Furthermore, benthic foraminiferal species composition represents mesohaline to oligohaline biofacies, showing clear similarities to modern Aegean closed lagoons (e.g., Koukousioura et al., 2012; Dimiza et al., 2016) (iv) after ~2000 cal BP, the silty clay was deposited, exhibits high magnetic susceptibility and the highest mud values of the sedimentary sequence (Fig. 1), in a fresh-water environment with possible river discharges. No fauna was detected in this phase, while fresh-water indicators and aquatic pollen were encountered in an environment analogue to today’s Ismarida Lake. Acknowledgements The authors would like to thank the “Molyvoti Project” headed by Professor Nathan Arrington, Department of Art and Archeology, Princeton University, for the financial support of the fieldwork and AMS datings. References Dimiza, M.D., Koukousioura, O., Triantaphyllou, M.V., Dermitzakis, M.D., 2016. Live and dead benthic foraminiferal assemblages from coastal environments of the Aegean Sea (Greece): Distribution and diversity. Revue de Micropaléontologie 59(1), 19-32. Karadimou, G., Vouvalidis, K., Syrides, K., Koukousioura, O., Aidona, E., 2016. Geomorphological and paleoenvironmental changes of Ismarida Lake during Holocene (N. Greece). Bulletin of the Geological Society of Greece 50(1), 424‐433. Koukousioura, O., Triantaphyllou, M.V., Dimiza, M.D., Pavlopoulos, K., Syrides, G., Vouvalidis, K., 2012. Benthic foraminiferal evidence and paleoenvironmental evolution of Holocene coastal plains in the Aegean Sea (Greece). Quaternary International 261, 105-117. Pavlopoulos, K., Triantaphyllou, M., Karkanas, P., Kouli, K., Syrides, G., Vouvalidis, K., Palyvos, N., Tsourou, T., 2010. Paleoenvironmental evolution and prehistoric human environment, in the embayment of Palamari (Skyros Island, Greece) during Middle-Late Holocene. Quaternary International 216, 41-53. Theodorakopoulou, K., Pavlopoulos, K., Triantaphyllou, M., Kouli, K., Tsourou, T., Bassiakos, Y., Zacharias, N., Hayden, B., 2009. Geoarchaeological studies in coastal area in Istron-Kalochorio (gulf of Mirabello-Eastern Crete): landscape evolution and palaeoenvironmental reconstruction. Zeitschrift für Geomorphologie 53(1), 55-70. Triantaphyllou, M.V., Kouli, K., Tsourou, T., Koukousioura, O., Pavlopoulos, K., Dermitzakis, M.D., 2010. Paleoenvironmental changes since 3000 BC in the coastal marsh of Vravron (Attica, SE Greece). Quaternary International 216, 14-22. Triantaphyllou, M.V., Pavlopoulos, K.P., Kouli, K., Koukousioura, O., Dimiza, M.D., Aidona, E., Syrides, G., Pallikarakis, A., Goiran, J.-P., Fouache, E., 2016. Multiproxy paleoenvironmental reconstruction: the Piraeus coastal plain case study. Bulletin of the Geological Society of Greece 50(1), 478-487. Vouvalidis, K., Syrides, G., Pavlopoulos, K., Papakonstantinou, M., Tsourlos, P., 2010. Holocene palaeoenvironmental changes in Agia Paraskevi prehistoric settlement, Lamia, Central Greece. Quaternary International 216, 64-74.

ABSTRACT. Background Coccolithophores have a widespread distribution in the photic zone, ranging from polar to tropical waters, but overall show preference to warm, low productivity regions (e.g., Winter et al., 1994; Karatsolis et al., 2017). Most coccolithophore taxa are more diverse and abundant in low and middle latitude warm, and stratified oligotrophic waters. However, certain species, such as Emiliania huxleyi, reveal an opportunistic and r-selected behavior (e.g., Tyrrell and Merico, 2004) thriving in high productivity areas and often form intense blooms over large areas of the ocean (e.g., Westbroek et al., 1993). The Black Sea is the largest semi-enclosed marginal sea and receives drainage from almost one-third of continental Europe. Intensive coccolithophore blooms (Emiliania huxleyi, primarily) are typical events for the Black Sea. According to satellite observations, on a temporal scale the most extended bloom occurs in May-June, although differences in intensity and area of coverage have been recorded (e.g., Cokacar et al., 2004; Kopelevitch et al., 2014; Triantaphyllou et al., 2014; Mikaelyan et al., 2015). These blooms can be detected by ocean color sensors as a result of light being scattering by the coccolith plates that are detached from cells. The optical signature of coccolithophore blooms on satellite true color images is a very bright patch of water with a milky turquoise color. The Black Sea is an ideal site in which to study the effect of biogeochemical properties on coccolithophore blooms.

Objectives The main aim of this study was to determine the spatial and vertical distribution patterns of living coccolithophores from the oxic surface zone in the western part of the Black Sea in June 2016.

Materials and methods The present study focuses on the analysis of 95 seawater samples from 33 stations from the inner (<50 m depth), outer (50–200 m depth) self and the open sea (>200 m depth), in the western part of the Black Sea, that was undertaken in June 2016 (2–24/06). For each sampling station, a surface sample was taken from 1 m depth and 1-4 more depths within the surface layer (5 m – 50 m), adjusted to bottom topography and bathymetry. Water samples were taken with a 5 L Niskin bottles positioned in a rosette over the CTD system of the ship.

Several physico-chemical parameters including temperature, salinity profiles were measured at most of the stations using a SBE-19 CTD-Rosette System. The amount of chlorophyll-a (Chl a) that corresponded to the 0.2-2.0 μm and >2.0 μm size classes was measured fluorometrically (Holm-Hansen et al., 1965). The coccolithophore composition and community structure was evaluated through Optical Microscopy. The samples were examined in a Leica DMLSP polarizing light microscope and the coccospheres per liter were calculated following the methodology of Jordan and Winter (2000).

Results and Discussion At the northern areas of the inner shelf the sea surface temperature ranged from 16 to 22 °C. In the outer shelf region the temperature increased reaching the values of ~21°–24 °C, whereas in the open sea the values fluctuate from 21 to 22 °C. The sea surface salinity was relatively low, both in the shelf and open sea areas. Generally, the salinity values ranged from the minima of < 17.5, near the northern shelf area reflecting the influx of fresh water from the Danube River to the maxima of 17.5–18.9 in the open sea. The spatial distribution (1 m depth) of Chl a was revealed from the seventeen samples collected mainly from the south-western part of the studied areas. Total Chlorophyll-a concentrations in surface waters ranged from 0.147 μg l-1 to 5.764 μg l-1. The values of Chl a were increased near the self-region with maxima in the northern stations, with decreasing trend towards the open sea stations. Living coccolithophores showed excessively high densities ranging from 2.44x104 to 7.63x106 coccospheres l–1. Emiliania huxleyi lightly calcified morphotypes (1.24x104–7.38x106 coccospheres l–1) dominated in the surface assemblage and constituted the 98% of the coccolithophore community. Differences in spatial distribution between inner self and open-sea environments were observed that are primarily associated with freshwater inputs and nutrients influx from the Danube River. A significant positive correlation between E. huxleyi density and Chl a concentrations (Pearson r=0.255, p<0.05) indicate a direct relationship between coccolithophores and chlorophyll-a. In general, Emiliania huxleyi was usually higher in the surface layer (up to around 35 m), and tended to decrease in density below ~35 m water depth, while Algirosphaera robusta occurred in high densities in the deeper parts (up to 7.94x106 coccospheres l–1), indicating low light availability below the thermocline. The present study suggests that some Syracosphaeraceae and Rabdosphaeraceae taxa such as Syracosphaera dilatata, Syracosphaera molischii, Acanthoica acanthifera, Acanthoica quattrospina and few holococcolithophores (Syracosphaera arethusae HOL and Helladosphaera cornifera) that have also been identified in the studied Black Sea water samples prove to thrive well in low salinities and relative eutrophic conditions.

Acknowledgments The material studied for coccolithophore analysis was provided during the BIO-OPT-2016 EUROFLEETS cruise, onboard the R/V Akademik.

References Cokacar, T., Oguz, T., Kubilay, N. 2004. Satellite-detected early summer coccolithophore blooms and their interannual variability in the Black Sea. Deep-Sea Research Part I, 54: 1017–1031. Holm-Hansen, O., Lorenzen, C.J., Holmes, R.W., Strickland, J.D.H., 1965. Fluorometric Determination of Chlorophyll. ICES J Mar Sci. 30(1), 3–15. Jordan, R.W., Winter, A., 2000. Assemblages of coccolithophorids and other living microplankton off the coast of Puerto Rico during January-May 1995. Mar. Micropaleontol. 39, 113–130. Karatsolis, B.-Th., Triantaphyllou, M.V., Dimiza, M. D., Malinverno, E., Lagaria, A., Mara, P., Archontikis, O., Psarra, S., 2017. Coccolithophore assemblage response to Black Sea Water inflow into the North Aegean Sea (NE Mediterranean). Continental Shelf Research 149, 138–150. Kopelevich, O.V., Burenkov, V.I., Sheberstov, S.V., Vazyulya, S.V., Kravchishina, M., Pautova, L.A., Silkin, V.A., Artemiev, V., Grigoriev, A. 2014. Satellite monitoring of coccolithophore blooms in the Black Sea from ocean color data. Remote Sensing of the Environment, 146: 113–123. Mikaelyan, A.S, Pautova, L.A., Chasovnikov, V.K., Mosharov, S.A., Silkin, V.A. 2015. Alternation of diatoms and coccolithophores in the northeastern Black Sea: a response to nutrient changes. Hydrobiologia, 755: 89–105. Triantaphyllou, M.V., Malinverno, E., Dimiza, M.D., Gogou, A., Athanasiou, A., Skampa, E., Tselenti, D., Thanassoura, E., Birli, A., Stavrakaki, I., Stavrakakis, S., Corselli, C., Lykousis, V. 2014. Coccolithophore biogeographic trends and export production in the Eastern Mediterranean and Black Seas. Journal of Nannoplankton Research, 34: 97–98. Tyrrell, T., Merico, A., 2004. Coccolithophores—From Molecular Processes to Global Impact, Ed. by H. R. Thierstein & J. R. Youngs (Springer, 2004), pp. 75–97. Westbroek, P., Brown, C. W., Bleijswijkbrownlee, J. Van C., Brummer, G. J., Conte, M., Egge, J., Fernandez, E., Jordan R., Knappertsbusch, M., Stefels, J., Verdhuis, M., Van Der Wal, P., Young, J., 1993. A model system approach to biological climate forcing: the example of Emiliania huxleyi. Global and Planetary Change, 8, 27-46. Winter, A., Jordan, R. W. & Roth P., 1994. Biogeography of living Coccolithophores in oceanic waters. In: A. Winter & W.G. Siesser (eds), Coccolithophores, p. 13-27, Cambridge University Press.

ABSTRACT. Abstract: The establishment of the Holocene stratigraphic configuration of deltaic successions around the Mediterranean has been the study of several researchers over the last few decades (e.g., Bruno et al., 2015), with much of the associated research being focused on sedimentological and geochemical analyses (e.g., Pechlivanidou et al., 2014), tectonics and geodynamics (e.g., Lafuerza et al., 2005) as well as seismic profile analyses (e.g., Styllas, 2014). Sperchios delta plain is located in central Greece and covers an area of 121.5 km2. The hydrological regime in the area and the tectonic activity in the basin have forced the river’s main channel to shift its course several times in the past, leading to the development of many deltaic prolongations and the creation of an extensive deltaic plain (Poulos et al., 1997). Earlier studies in Sperchios delta plain have primarily been focused on the reconstruction of the shoreline at the time of the ancient battle terrain of Thermopylae (Kraft et al., 1987; Vouvalidis et al., 2010a), while more recently the palaeogeography of the Late stages Holocene Sperchios delta plain has been described by Pechlivanidou et al. (2014) and Tsakalos et al. (2016), based on palaeontological, geochemical and sedimentological analyses on deltaic deposits. However, numerical ages of the different deltaic sedimentary faces have been very limited, bringing uncertainties on the sequential history of the upper part of Sperchios delta plain. Previous chronological research in the delta (Pechlivanidou et al., 2014; Vouvalidis et al., 2010b) was based on archaeological and radiocarbon dates, with 14C ages bearing a number of limitations (e.g., sample contamination and uncertainties associated with the estimation of the C-14 to C-12 ratio). Furthermore, even though the luminescence dating techniques are now extensively applied to variety of sedimentary environments (e.g., aeolian, fluvial and marine), their application on fluvial and deltaic deposits still limited, since incomplete bleaching of sediment grains may be apparent. In such environments, sunlight exposure of sediments transported by fluvial processes may be very short-time and/or water turbulence may not allow direct sunlight exposure and thus full resetting of their luminescence signal (Dietlefsen, 1992; Rendell et al., 1994). In this regard, an absolute dating study by Tsakalos et al., (2018) examined the applicability of the Optically Stimulated Luminescence (OSL) technique on sand sized (coarse) quartz from Sperchios delta deposits and provided a reliable chronological framework for the upper (~20 m) sedimentary deposits of Sperchios delta plain. This study also revealed that the distributions of the “equivalent dose” (DE) values of the dated coarse grained quartz are over-dispersed, which may be considered as typical for fluvial sediments (e.g., Arnold et al., 2009). However, this problem of obtaining the best estimate of DE and thus calculating a reliable age was overcome by the use of a number of statistical approaches. Here we present a new-detailed Holocene chronological framework for the Sperchios delta along with sedimentation rates of its depositional sequences. Our approach is based on an enhanced chronological model which builds on the earlier set of luminescence ages on coarse quartz produced in the area by Tsakalos et al. (2018). The current study adopts the systematic employment of the luminescence dating techniques on fine (4-11 μm) quartz and coarse (80-125 μm) feldspar grains. The use of fine quartz will allow checking the hypothesis of a more effective resetting mechanism of the fine grained fraction (as opposed to coarser) during transportation and deposition. For age consistency check, samples dated here are exactly the same as the ones dated using the conventional Single Aliquot Regenerative (SAR)-OSL protocol in the study by Tsakalos et al., (2018). Samples were collected from five boreholes and are associated with different sedimentary facies (transgressive and regressive deposits that overlay late Pleistocene deposits) Fig. 1. To this end, the produced ages put additional strain on the applicability and reliability of the different luminescence techniques for dating deltaic deposits.

Fig. 1 Study area and sampling sites of the five cores (after Tsakalos et al., 2018).

Our luminescence dating results provided evidence of an Early to Late Holocene deposition for the upper 20 m of the delta and shorted in chronostratigraphic order. Further, the absolute ages derived by both fine quartz and coarse feldspar grains the are in agreement with independent previous choronological studies (radiocarbon dating) conducted in the area (Pechlivanidou et al., 2014) and in great consistency with the coarse quartz OSL ages by Tsakalos et al. (2018). The produced information adds to the widely accepted consensus regarding a consistent late Pleistocene to Holocene stratigraphic configuration of Mediterranean deltas while at the same time further contribute to the development of an evolutionary model of Mediterranean low-lying coastal areas subject to rising sea level rates. References Arnold, L.J., Roberts, R.F., Galbraith, S.B., DeLong, S.B., 2009. A revised burial dose estimation procedure for optical dating of young and modern-age sediments. Quaternary Geochronology 4 (4), 306-325. Bruno, L., Amorosi, A., Severi, P., and Bartolomei, P., 2015. High-frequency depositional cycles within the late Quaternary alluvial succession of Reno River (northern Italy). Italian Journal of Geosciences 134, 339-354. Ditlefsen, C., 1992. Bleaching of K-feldspars in turbid water suspensions: a comparison of photo- and thermoluminescence signals. Quaternary Science Reviews 11, 33-38. Kraft, J., Rapp, G., Szemler, G., Tziavos, Ch., and Kase, E., 1987. The pass of Thermopylae, Greece. Journal of Field Archaeology 14, 181-198. Lafuerza, S., Canals, M., Casamor, J.L., Devincenzi, J.M., 2005. Characterization of deltaic sediment bodies based on in situ CPT/CPTU profiles: A case study on the Llobregat delta plain, Barcelona, Spain. Marine Geology 222-223, 497-510. Pechlivanidou, S., Vouvalidis, K., Løvlie, R., Nesje, A., Albanakis, K., Pennos, C., Syrides, G., Cowie, P., Gawthorpe, R., 2014. A multi-proxy approach to reconstructing sedimentary environments from the Sperchios delta, Greece. The Holocene 24 (12), 1825-1839. Poulos, S., Leontaris, S., Collins, M.B., 1997. Sedimentological and clay mineralogical investigations in Maliakos Gulf, eastern Greece. Bollettino di Geofisica Teorica ed Applicata 38 (3-4), 267-279. Rendell, H.M., Webster, S.E., Sheffer, N.L., 1994. Underwater bleaching of signals from sediment grains: New experimental data. Quaternary Science Reviews 13, 433-435. Styllas, M., 2014. A simple approach for defining Holocene sequence stratigraphy using borehole and cone penetration test data. Sedimentology 61, 444-460. Tsakalos E., Dimitriou E., Triantaphyllou M., Kouli K., Dimiza M., Anagnostou C., Kazantzaki M., 2016. Late Pleistocene-Holocene environmental changes on Sperchios delta plain-central Greece. The MedCLIVAR 2016 conference, 26-30 Sept 2016, book of Abstracts, Athens, Greece. Tsakalos, E., Dimitriou, E., Kazantzaki, M., Anagnostou Ch., Christodoulakis J., Filippaki E., 2018. Testing optically stimulated luminescence dating on sand-sized quartz of deltaic deposits from Sperchios delta plain, Greece. Journal of Palaeogeography 7, 130-145. Vouvalidis, K., Syrides, G., Pavlopoulos, K., Papakonstantinou, M., Tsourlos, P., 2010b. Holocene palaeoenvironmental changes in Agia Paraskevi prehistoric settlement, Lamia, Greece. Quaternary International 216, 64-74. Vouvalidis, K., Syrides, G., Pavlopoulos, K., Pechlivanidou, S., Tsourlos, P., Papakonstantinou, M., 2010a. Palaeogeographical reconstruction of the battle terrain in Ancient Thermopylae, Greece. Geodinamica Acta 23 (5-6), 241-253.

ABSTRACT. The employment of luminescence dating techniques on coastal sediments from North Evoikos Gulf (Central Greece) revealed that Optically Stimulated Luminescence (OSL) and Isothermal Thermoluminescence (ITL) natural signals of quartz grains are close to saturation (Figure 1a,1b) and also yielding broadly scattered equivalent dose (De) values, thus perplexing the calculation of reliable luminescence ages. To overcome this problem, Infrared Stimulated Luminescence (IRSL) dating of feldspar was attempted, which was proven more suitable for such sediments, as it showed higher saturation levels. Natural luminescence signal from feldspar grains (Figure 2) produced accurate De values, the reliability of which was confirmed by the properly corrected sensitivity changes that take place during measurements, as well as a number of validation tests (namely, dose recovery and preheat plateau tests). The post-IRSL SAR protocol after Thiel et al. (2011) was employed which use an elevated temperature both during preheating and stimulating of the feldspar samples. Our luminescence dating results on the coastal samples provided ages that go back to the Middle Pleistocene (Figure 3). The reliability of the post-IRSL ages are further confirmed by a number of previous palaeontological studies in the area (Kumadakis, 1969; Keraudren, 1975; Phillip, 1974; Lemeille, 1977; Rondoyanni-Tsiambaou, 1984; Genre 1999; Mauridis et al., 2006), as they provided ages which are in fair agreement with the dating results of this study. Based on the derived absolute ages, the mean sedimentation rate in the study area was also determined, which could be considered as being relatively low, ranging from 0.15 to 0.7 cm/yr, similar to the sedimentation rate estimated by previous studies in the area (Kamperi and Sakellariou, 2006). In addition, a mean uplift rate of 0.11 to 0.15 mm/y was calculated for the southern part of North Evoikos Gulf since the Middle Pleistocene. During the Middle Pleistocence, North Evoikos Gulf was periodically becoming a lake, when the sea level was low enough, not exceeding the maximum depth of Lichades Strait, while a change to a lagoon environment was taking place when seawater from the Aegean Sea entered the Gulf. Probably, the first entry of seawater into the North Evoikos Gulf took place at the beginning of the Middle Pleistocene, as indicated by the presence of brackish deposits, sitting on layers of successive lacustrine and terrestrial deposits of an older age. This is also confirmed by the presence of mollusk fauna, which is also present on the Caspian and Black Sea, thus signifying a connection between Evoikos Gulf and the Black Sea and the Caspian Sea, through the Marmara Sea and the Dardanelles Strait respectively. This study revealed that post-IRSL dating was a reliable technique for establishing the chronological framework of North Evoikos Gulf and an alternative trustworthy dating technique when OSL on quartz suffers from saturation. Furthermore, the produced post-IRSL ages are the first Middle Pleistocene ages reported for Greek clastic sediments using the luminescence dating techniques.

Figure 1. Growth curves of a quartz aliquot close to saturation using (a) the OSL and (b) the ITL dating techniques.

Figure 2. Growth curve of an aliquot containing feldspar grains using the post-IRSL protocol.

Figure 3. post-IRSL Middle Pleistocene ages of North Evoikos Gulf, plotted on an eustatic curve (modified after Bintanja et al., 2005). Acknowledgements This study was supported by the National Technical University of Athens, faculty of Geological Sciences, School of Mining and Metallurgical engineering. References Genre, C., 1999. Neotectonics and Late Holocene terraces. The example of Euboea (Central Eastern Greece). Geomofphologie: relief, processus, environement 2, 143-158. Kamperi, E., Sakellariou, D., 2006. Active sedimentation rates in N. Evoikos Gulf and Gulf of Alkyonides. Comparison with Pb-210 method, 8th Panhellenic Symposium of Oceanography and Fishing, Hellenic Centre for Marine Research, Thessaloniki. (In Greek) Keraudren, B., 1975. Essai de stratigraphie et de paleogeographie du Plio-Pleistocene egeen. Bulletin de la Société géologique de France VII (17), 1110-1120. Kumandakis I., 1969. The geology of Grammousa Island (N. Evoikos Gulf). Annales Géologique des Pays Helléniques 22, 295-299. (In Greek) Lemeille, F., 1977. Etudes neotectoniques en Grece centrale nord-orientale (Eubee centrale, Attique, Beotie, Locride). Thèse Doctorat - de 3eme cycle, Université de Paris, Paris, XI, 173 p. Mavrides, A., 2006. Geological map of Greece scale 1:50.000, Chalkida sheet, IGME, Athens. Philip, H., 1974. Etude néotectonique des rivages égéens en Locride et en Eubée nord orientale, Thèse de 3eme cycle, Académie de Montpellier, Paris. Rondoyanni-Tsiambaou, Th., 1984. Etude néotectonique des rivages occidentaux du canal d’ Atalandi (Grèce Centrale). Thèse Doctorat, Université de Paris sud Centre d’ Orsay, Paris. Thiel, C., Buylaert, J.P., Murray, A.S., Terhorst, B., Hofer, I., Tsukamoto, S., Frechen, M. 2011. Luminescence dating of the Stratzing loess profile (Austria) - Testing the potential of an elevated temperature post-IR IRSL protocol, Quaternary International 234(1-2), 23-31.

ABSTRACT. Background The Malta Plateau is an area of particular interest since it is affected by active gas venting phenomena, which lead to the formation of mud volcanoes. Furthermore, tabular reliefs occur in this area (Fig. 1) and are the objective of this work. Previous studies focused on the morphological description of this feature (Savini et al., 2009) and on its evolution basing upon paleontological, sedimentological and mineralogical analyses (Bracchi et al., 2019).

Fig. 1. Location of the investigated tabular relief. Black star indicates the core site (modified from Bracchi et al., 2019).

Objectives This work proposes a quantitative description of the variation of foraminifera and ostracod assemblages throughout a sedimentary core, in order to detail the paleoenvironmental evolution of this tabular relief. Methods Core MV02_GC01 (36°34.2147′N; 14°30.2232′E), 176 cm long, was sampled on the flank of the tabular relief at 141 m depth and divided into two sections: section 1 from cm 0 to cm 76 cm, and section 2 from cm 76 to cm 176. Samples for micropaleontology were collected at 10 cm resolution, with a total of 17 samples from the top to the bottom. For each sample, 3 g of sediment were wet-sieved and splitted. Benthic foraminifera were hand-picked, identified and counted, whereas planktonic foraminifera and ostracods are still under study. Six samples (10-20-40-50-100-160 cm) have been collected and analyzed for nannofossil biostratigraphy. Results A total of 7218 benthic foraminifera were identified, belonging to 70 species. According to their habitat requirements, benthic foraminifera were grouped in four ecological categories, whose relative abundance was assessed: transported, lagoonal, marine and epiphytes. The downcore variations of these categories are described below and shown in Fig. 2: - Transported: group composed by reworked Miliolids, Ammonia beccarii and Elphidium crispum. These specimens are characterized by an altered coloration and an intense abrasion on their tests. Two or even three cycles of upward-decreasing abundance can be identified. The relative abundance of this category is remarkably large in the lower section of the core, with a maximum value of 37,89% at -160 cm, then it decreases until -80 cm, where there is another peak of 33,04%; finally, it decreases again towards the top, reaching the 0% at -10 cm. - Lagoonal: group composed by Haynesina depressula, H. germanica, Pararotalia spp., Ammonia tepida, Elphidium granosum and E. translucens; this category has a stable relative abundance of about 10-15% throughout the whole core, with a maximum value of 22,92% at -30 cm. - Marine: group composed by in situ Miliolids (small and with a white and well-preserved test), Bolivina spp., Cassidulina carinata, Globocassidulina subglobosa, Bulimina spp., Uvigerina spp., Valvulineria spp., Discorbis spp., Cibicides refulgens and Nonion spp.; the relative abundance of this category has an upward increasing trend, with a maximum value of 70,00% at -20 cm. - Epiphytes: group composed by Textularia spp., Reussella spinulosa, Neoconorbina terquemi, Rosalina spp. and Asterigerinata mamilla; this category is directly connected to the marine one regarding the ecological meaning, since most of these identified epiphytes is related, in the Mediterranean, to a fully marine environment with Posidonia oceanica; the relative abundance of this category has an upward increasing trend, with a large peak corresponding to 33,02% at -60 cm.

Fig. 2 Plots showing the relative abundance of the four ecological categories (A: transported; B: lagoonal; C: marine; D: epiphytes) along the sedimentary core expressed as percentage (%).

The ratio of planktonic foraminifera vs total foraminifera (%P) corrected for infaunal species, expressed as percentage (van der Zwaan et al., 1990) is notably large in the lower section of the core, with values around 80% from -150 to -90 cm and a maximum of 84,35% at -140 cm, while, starting from -90 cm, this ratio decreases towards the top, with a relevant increase in the last two samples.

Conclusions The variation in the relative abundance of ecological groups is interpreted as a transgressive cycle from the Last Glacial Maximum or previous glacial phases. The upward decrease in the transported tests is coupled with an increase in the percentage of marine and epiphytes: this suggests an upward deepening trend. Such results well agree with the data of Bracchi et al. (2019), although the analysis of planktonic foraminifera and 14C dating will allow a better constrain of the evolution of the tabular relief. High values of %P in the lower section of the core are still debated. They could result from: an intense erosional activity during glacial phases, vertical migration of older material in correspondence of mud volcanoes or peculiar paleoecological conditions.

Acknowledgements We acknowledge the shiptime through the 2006-2007 Italian PRIN ‘MESC’ program, funded by the Italian Ministry of Research and Technology (MIUR). FG benefitted from a grant through the Erasmus Traineeship Program to work at the University of Athens. This is a scientific contribution of Italian Project MIUR - Dipartimenti di Eccellenza 2018-2022 References Bracchi V.A. Basso D., Savini A., Corselli C., 2019. Algal reefs (Coralligenous) from glacial stages: Origin and nature of a submerged tabular relief (Hyblean Plateau, Italy). Marine Geology, 411:119-132. Savini, A., Malinverno, E., Etiope, G., Tessarolo, C., Corselli, C., 2009. Shallow seep related seafloor features along the Malta plateau (Sicily channel – Mediterranean Sea): Morphologies and geo-environmental control of their distribution. Mar. Pet. Geol. 26, 1831–1848. Van der Zwaan, G.J., Jorissen, F.J., De Stigter, H.C., 1990. The depth dependency of planktonic/ benthic foraminiferal ratios: constraints and applications. Marine Geology 95, 1–16.

ABSTRACT. The last half-century considerable interest has developed on the role of the (sub) tropical oceans in climate change, and in particular, oceanic sub-basins and marginal seas that are often more responsive to paleoceanographic and paleoclimatic changes than broader global ocean basins, because of their smaller size and partial isolation (Kontakiotis, 2016; Kontakiotis et al., 2013; Marino et al., 2009; Antonarakou et al., 2015, 2019). As an example, the small volume of the Mediterranean Sea, compared with ocean basins, causes changes in its climatic forcing to be recorded virtually instantaneously in palaeoceanographic proxy data, such as stable isotope and other geochemical ratios, and microfossil abundances. The basin’s limited communication with the open ocean implies that any climatic signals will be recorded in an amplified fashion in Mediterranean properties, such as temperature, salinity and specific elemental concentrations (Kontakiotis, 2012). Especially the eastern Mediterranean is ideal for addressing proposed forcing mechanisms of tropical climate variability (Kontakiotis, 2016; Casford et al., 2007) due to its intermediate position between the higher-latitude (i.e. North Atlantic-influenced) and lower-latitude (i.e. monsoonally influenced) climate systems. This heightened sensitivity to the effects of climate variations seems to be especially true for the Aegean Sea, because of the combination of its semi-isolation from the rest of the Mediterranean Sea, its small size, large topographic contrasts acting as specific boundary conditions, the abundance of local freshwater inputs and the regional climate.

To better understand the impact of these parameters on the regional climate, a number of studies has focused on the paleoceanographic evolution of the basin during the late Quaternary (e.g., Drinia et al., 2016; Kontakiotis, 2016; Koutrouli et al., 2018). However, the reconstruction of the variability of late Quaternary climate needs a detailed chronostratigraphic control. In this respect, a notable contribution is particularly required by micropaleontological, biogeochemical, and sedimentological studies. In particular, morphological and compositional changes in the planktonic foraminiferal assemblages recorded in marine sediments and/or the water column provide detailed information on the physical and chemical properties of the surrounding water masses and their relationships with climatic variability (Antonarakou et al., 2015; Kontakiotis, 2016; Zarkogiannis et al., 2019). They also allow the definition of a detailed sequence of regional eco-bioevents for the late Quaternary, reflecting the climatic oscillations that represent an important tool for an accurate subdivision of the late Quaternary stratigraphic record and facilitate correlations between sites in the different sub-basins (Casford et al., 2007; Budillon et al., 2009; Triantaphyllou et al., 2009; Siani et al., 2010; Lirer et al., 2013; Antonarakou et al., 2019).

This study aimed at achieving high resolution sediment cores at sub-centennial to centennial scale, and therefore highlights the planktonic foraminiferal abundance variations during the last glacial cycle from two gravity cores (M-22-67and NS-18) along the Aegean Sea. In particular, the relative abundance of selected climate-sensitive planktonic foraminiferal species have led us to identify several eco-bioevents in G. ruber alba, G. ruber rosea, G. bulloides, G. inflata, T.quinqueloba, N. pachyderma, N durtertrei, O. universa, G. sihonifera, G. trilobus, G. scitula, G. rubescens, G. glutinata, and G. trucatulinoides. All faunal events have been defined by morphospecies evolution, first local occurrences and disappearances of a given species, prominent changes in coiling direction, frequency shifts and strong inflections in the faunal record, with reference to the pioneer work of Casford et al. (2007). The similarity between the two north and south Aegean records underlines the utility to support conventional dating methodologies with different constraints, and further reveals a powerful tool for reliably correlating marine records between comparable deep-sea marginal settings and/or an original dating tool for coeval sequences of this region. Overall, the bioevents chronology combined with 14C-AMS data could be used to define an updated and comprehensive age model that can be considered as a useful paleoclimatic and stratigraphic reference record for the entire eastern Mediterranean Sea.

References Antonarakou, A., Kontakiotis, G., Mortyn, P.G., Drinia, H., Sprovieri, M., Besiou, E., Tripsanas, E., 2015. Biotic and geochemical (δ18Ο, δ13C, Mg/Ca, Ba/Ca) responses of Globigerinoides ruber morphotypes to upper water column variations during the last deglaciation, Gulf of Mexico. Geochim. Cosmochim. Acta 170, 69–93, doi: 10.1016/j.gca.2015.08.003. [Journal Article] Antonarakou, A., Kontakiotis, G., Karageorgis, A.P., Besiou, E., Zarkogiannis, S., Drinia, H., Mortyn, P.G., Tripsanas, E., 2019. Eco-biostratigraphic advances on late Quaternary geochronology and paleoclimate: The marginal Gulf of Mexico analogue. Geol. Quart. 63 (1). [Journal Article] Budillon, F., Lirer, F., Iorio, M., Macri, P., Sagnotti, L., Vallefuoco, M., Ferraro, L., Garziglia, S., Innangi, S., Sahabi, M., Tonielli, R., 2009. Integrated stratigraphic reconstruction for the last 80 kyr in a deep sector of the Sardinia Channel (Western Mediterranean). Deep-Sea Res. II 56, 725–737. [Journal Article] Casford, J.S.L., Abu-Zied, R.H., Rohling, E.J., Cooke, S., Fontanier, C., Leng, M., Millard, A., Thomson, J., 2007. A stratigraphically controlled multiproxy chronostratigraphy for the eastern Mediterranean. Paleoceanography, 22, PA4215, doi:10.1029/2007PA001422. [Journal Article] Drinia, H., Antonarakou, A., Tsourou, T., Kontakiotis, G., Psychogiou, M., Anastasakis, G., 2016. Foraminifera eco-biostratigraphy of the southern Evoikos outer shelf, central Aegean Sea, during MIS 5 to present. Cont. Shelf. Res. 126, 36–49. [Journal Article] Kontakiotis, G., 2012. Palaeoceanographic and palaeoclimatic study of Eastern Mediterranean during Late Quaternary, based on planktonic foraminiferal assemblages, PhD Thesis, National & Kapodistrian University of Athens, Greece, pp. 1–247. [Dissertation] Kontakiotis, G., 2016. Late Quaternary paleoenvironmental reconstruction and paleoclimatic implications of the Aegean Sea (eastern Mediterranean) based on paleoceanographic indexes and stable isotopes. Quater. Internat. 401, 28–42, doi:10.1016/j.quaint.2015.07.039. [Journal Article] Koutrouli, A., Anastasakis, G., Kontakiotis, G., Ballengee, S., Kuehn, S., Pe-Piper, G., Piper, D.J.W., 2018. The early to mid-Holocene marine tephrostratigraphic record in the Nisyros-Yali-Kos volcanic center, SE Aegean Sea. J. Volc. Geoth. Res., 366, 96–111. [Journal Article] Lirer, F., Sprovieri, M., Ferraro, L., Vallefuoco, M., Capotondi, L., Cascella, A., Petrosino, P., Insinga, D.D., Pelosi, N., Tamburrino, S., Lubritto, C., 2013. Integrated stratigraphy for the Late Quaternary in the eastern Tyrrhenian Sea. Quat. Int. 292, 71–85. [Journal Article] Marino, G., Rohling, E.J., Sangiorgi, F., Hayes, A., Casford, J.L., Lotter, A.F., Kucera, M., Brinkhuis, H., 2009. Early and middle Holocene in the Aegean Sea: interplay between high and low latitude climate variability. Quat. Sci. Rev. 28, 3246–3262. [Journal Article] Siani, G., Paterne, M., Colin, C., 2010. Late Glacial to Holocene planktic foraminifera bioevents and climatic record in the South Adriatic Sea. J. Quat. Sci. 25(5), 808–821. [Journal Article] Triantaphyllou, M.V., Antonarakou, A., Kouli, K., Dimiza, M., Kontakiotis, G., Papanikolaou, M.D., Ziveri, P., Mortyn, P.G., Lianou, V., Lykousis, V., Dermitzakis, M.D., 2009. Late Glacial-Holocene ecostratigraphy of the south-eastern Aegean Sea, based on plankton and pollen assemblages. Geo. Mar. Lett. 29(4), 249–267. [Journal Article] Zarkogiannis, S.D., Antonarakou, A., Tripati, A., Kontakiotis, G., Mortyn, P.G., Drinia, H., Greaves, M., 2019. Influence of surface ocean density on planktonic foraminifera calcification. Scientific Reports, 9, 533, DOI:10.1038/s41598-018-36935-7. [Journal Article]

ABSTRACT. Background-Objectives Coccolithophore assemblages that are recorded in marine sediments generally comprise a successful palaeontological tool for the reconstruction of the paleoclimatic and paleoceanographic conditions in the geological past (e.g., Triantaphyllou et al., 2009; Gogou et al., 2016), as they represent reliable indicators of environmental conditions (e.g., Baumann et al., 2000). However, little is known about the transformation of living coccolithophore communities into coccolith assemblages within the underlying sediments. In the oligotrophic waters of the Eastern Mediterranean Sea, the high seasonality of the oceanographic parameters affects the coccolithophore abundance and productivity (e.g., Dimiza et al., 2015). The North Aegean Sea (NE Mediterranean) displays less oligotrophic characteristics during the highest productivity spring period (Ignatiades et al., 2002). In the North Aegean Sea, surface Black Sea water outflows from the Dardanelles and meets the salty Levantine waters coming from the southern part of The Aegean. Due to the hydrographic regime, North Aegean supported a deep-water formation, under the influence of anomalously cold winters, known as the Eastern Mediterranean transient (EMT), which has been proven to ventilate the water column of the basin from the surface down to 650 m (Velaoras et al., 2017). The present study uses new data from the North Aegean sampling site M2, provided by sediment trap time series (Skampa et al., 2019), surface sediments combined with plankton samples (Dimiza et al., 2015) and a sediment core record (Gogou et al., 2016), in order to make a synthesis of the coccolithophores’ regime in the photic zone and assess their contribution to the sinking matter towards the seafloor, their preservation as surface sediment particles and, finally, their impact to the sedimentary record (Skampa et al., 2019). The understanding of the modifications between the plankton vs. the exported assemblages and the sediment taphocoenoses can further establish coccolithophores as valuable proxies for the investigation of water column response to paleoceanographic changes (e.g., dense water formation events) in the North Aegean and analogous oceanic sites of deep water formation.

Methods Quantitative coccolithophore analyses were performed on plankton samples datasets from the Athos basin in the North Aegean Sea (Athos basin-M2 site), which have been collected during January and May 2011 (Dimiza et al., 2015). In addition, the sinking particulate matter derived from a sediment trap deployed at 500 m depth in the Athos basin (M2 site) was examined in order to estimate export fluxes for the time interval January- December 2011 (Triantaphyllou et al., 2014) and October 2014-November 2015 (Skampa et al., 2019). Coccolithophore analyses of surface and core sediments from a 48-cm long multicore (M2), retrieved in 2011 from the same site in the North Aegean Sea (Athos basin, water depth 1018 m), have been conducted in a decadal to multi-decadal high resolution record (Gogou et al., 2016).

Results and Discussion Emiliania huxleyi was the dominant species in all sampling types, occurring in high relative abundances in the current plankton (~90%) and sediment trap samples (~70%), especially during the low-temperature, high precipitation and max Chl-a winter-spring period. Emiliania huxleyi prevailed in the plankton samples with the subordinate presence of Syracosphaeraceae. The species Florisphaera profunda was not included in the upper water column plankton assemblage, most probably due to sampling depth limitations, but was present in the sediment traps and surface sediments, presuming to flourish in nutrient-enriched layers below the sampled 100 m water column depth. Plankton samples revealed a well- developed upper euphotic zone community but several fragile Syracosphaeraceae and holococcolithophore species were not present in the sinking assemblage or on the seafloor; apparently, currents and circulation patterns of the North Aegean have an impact on the distribution of coccolithophore assemblages and convert them while sinking from the euphotic zone to the seafloor. However, the main features of the living assemblages were generally preserved (Skampa et al., 2019). Sediment trap calcareous nannoplankton multiannual mean fluxes documented similar values to the accumulation rates recorded in the surface sediment (Skampa et al., 2019). Apart from the loss of the more fragile holococcolithophore species and the delicate Algirosphaera robusta, the main features of the living assemblages were generally preserved on the seafloor, pointing out calcareous nannoplanktons’ importance as reliable proxy for paleoenvironmental reconstructions. The coccolithophore assemblage of the past 500 years revealed a periodic occurrence of “E. huxleyi dominance” intervals (~60%), indicating strong water column convection EMT-like events, which have been described in the recent fossil record (last 500 years; Gogou et al., 2016; Incarbona et al., 2016), coupled with positive shifts of the North Atlantic Oscillation (NOA) and volcanic activity within the Dalton solar minimum (Skampa et al., 2019). In contrast, the analogous occurrence of “F. profunda dominance” intervals may be linked to increased sea surface temperatures, and stratified conditions in the water column potentially associated with Black Sea Water intrusions (Skampa et al., 2019).

ABSTRACT. Marine Geomorphology and environmental status of Elefsis Bay and inner Saronikos Gulf, Greece. A multidisciplinary analysis. A. Katsigera1, M. Dimiza1, O. Koukousioura1, A.-I. Anastasiadis3, K. Pavlopoulos4, M. Triantaphyllou1 (1) Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Panepistimioupolis 15784 Athens, Greece, annakat@geol.uoa.gr (2) Aristotle University of Thessaloniki, School of Geology, 54124, Thessaloniki, Greece (3) Laboratory Mineralogy-Geology, Agricultural University of Athens, Iera Odos 75,11855 Athens, Greece (4) Paris Sorbonne University Abu Dhabi, Geography and Planning Department, P.O. 38044, Abu Dhabi, United Arab Emirates.

Introduction

Saronikos Gulf is located in the Aegean Sea between Attica and eastern Peloponnese Peninsula and is considered as a hot spot site for the particular environmental conditions and sea floor morphology. Through the ages, the coastal areas surrounding the gulf where used for economic and strategic purposes, with the most important of these being the Pireaus port and Elefsis Bay. Both are located on the north eastern part of the gulf and are strongly linked to human activities since the beginning of the ancient greek civilization. The area holds a great geomorphological and environmental interest, due to the human intervention since the ancient times but also due to the various landforms and processes that form its amazing underwater and coastal landscapes. In addition, the industrial activities along the coast of Elefsis Bay in the north east of Saronikos Gulf, affect the ecosystems, leaving traces of human activity that impacts the environmental status of the inner Saronikos Gulf. Foraminifera are one of the most spread and diverse group of meiofauna. Especially benthic foraminifera are commonly used as bio-indicators of both natural and human-stressed environments and are increasingly used in environmental monitoring in coastal and marginal marine ecosystems (e.g., Dimiza et al., 2016a, b).

Objectives

The main aim of this study is to create bathymetry maps in order to record the coastal and marine geomorphology of the gulf and to show the dynamic evolution of the coastline for the past 11.500 years. In addition, the study of foraminiferal thanatocoenoses in relation with their bathymetric distribution aims to relate the marine landforms with the recent processes and environmental conditions and efficiently describe the environmental profile of the area. Materials and methods For the creation of the bathymetry map we used a combination of data collected from field studies and available archive data from the Hellenic Center for Marine Research (HCMR) and the Institute of Geology and Mineral Exploration (IGME). Gis techniques (ArcGis from ESRI) were used to record the bathymetry of the gulf. Concerning the foraminiferal analysis, sediments were collected as small push-cores (mean depth about 10 cm) from box corers onboard the R/V Aegaeo from 12 sampling stations, four in Elefsis Bay and eight in Saronikos Gulf in February 2016, at water depths ranging from 15 to 95 m. Surface sediments (0-1 cm) from each station were collected and were immediately stained with rose Bengal dissolved in 70% ethanol (2g l-1) to facilitate the distinction between live and dead foraminifera. Approximately 2g of each sample was washed in the laboratory and sieved over 125μm and 63μm mesh and oven dried. A total of up to 300 not stained (dead) handpicked benthic foraminifera for each sample were obtained using an Otto microsplitter. All subsamples were examined under a Leica APO S8 stereoscope, following Cimerman and Langer (1991), Dimiza et al. (2016a), Milker et al. (2009) and Sgarrella and Moncharmont Zei (1993) for species classification and species relative abundances have been calculated. Proportional Similarity (PS) between the species composition of dead and living foraminiferal associations was calculated using the Renkonen index (Renkonen, 1938). Results – Discussion The benthic foraminiferal assemblage structure (H’ index) and the ecological quality classification tool, Foram Stress Index (FSI) as plotted in the georeferenced maps indicated an environmental amelioration for Inner Saronikos Gulf; e.g., upgrade of Ecological Quality Status (EcoQS) from moderate to good quality during the investigated time interval 2012-2016. In contrast, the central part of the Elefsis Bay evidenced an on-going poor environment status throughout the monitoring period. As this part of Saronikos Gulf is experiencing severe oxygen depletion due to limited water circulation during summer, further sampling during the summer period is needed to explore any seasonal difference that can be recorded in the foraminiferal assemblages. A low-diversity assemblage, dominated by stress-tolerant Ammonia tepida and Bulimina spp., was characteristic of samples from Elefsis Bay. Samples from the western and central part of Saronikos Gulf were the most variable, characterized by a mix of stress-tolerant and more sensitive taxa, especially Bulimina spp. and Nonion fabum. In contrast, samples from the coast of Salamis and at the eastern sector of the gulf were characterized by a diverse assemblage that mostly included miliolids and small, epiphytic rotaliid taxa, and the dominant species Haynesina germanica and Bulimina aculeata. According to the foraminiferal distribution, it appears that north east Elefsis Bay the high levels of Bulimina spp. indicate periods of anoxic events along with eutrophic conditions while western and central Saronikos is more variable with areas affected by stress and low oxygen periods in the south east of Salamis island and less stress environments in the north east of the island. In the shallow shelf environments of the Mediterranean Sea, the main environmental parameters affecting the distribution pattern of the benthic foraminifera are temperature, salinity and substrate type (Basso and Spezzaferri, 2000; Hyams-Kaphzan et al., 2008; Milker et al., 2009; Samir et al., 2003). Several ecological studies have demonstrated that the environmental variables controlling the distribution pattern of benthic foraminiferal assemblages vary with water depth (e.g., De Rijk et al., 2000; Rossi and Horton, 2009), while Milker et al. (2009) showed distinct benthic foraminifera bathymetric zonation linked to substrate, water turbulence and food availability. According to Dimiza et al. (2016a) several environmental conditions impact on the taphonomic processes. The studied assemblages provided us concerning the relation of dead fauna and bathymetry when considering Renkonen index. The calculated PS exhibited high degree of similarity with an average value of PS= 67 ±6.8 in Elefsis Bay and intermediate similarity values with an average of PS= 31 ±5.9 in the inner Saronikos, suggesting negligible transport processes in the shallower parts of the gulf.

References

Basso, D., Spezzaferri, S., 2000. The distribution of living (stained) benthic foraminifera in Iskenderun Bay (eastern Turkey): a statistical approach. Soc. Paleontol. Ital. 39, 359–379. Cimerman, F., and Langer, M.R. (1991). Mediterranean foraminifera. Acad. Sci. Artium Slov. Dela Opera 30 Cl. IV Hist. Nat. 118, pls. 93. De Rijk, S., Jorissen, F.J., Rohling, E.J., Troelstra, S.R., 2000. Organic flux control on bathymetric zonation of Mediterranean benthic foraminifera. Mar. Micropaleontol. 40, 151–166. Dimiza, M. D., Koukousioura, O., Triantaphyllou, M. V., Dermitzakis, M. D., 2016a. Live and dead benthic foraminiferal assemblages from coastal environments of the Aegean Sea (Greece): Distribution and diversity. Revue de Micropaléontologie, 59(1), 19–32. Dimiza, M.D., Triantaphyllou, M.V., Koukousioura, O., Hallock, P., Simboura, N., Karageorgis, A.P., Papathanasiou, E., 2016b. The Foram Stress Index: A new tool for environmental assessment of soft-bottom environments using benthic Foraminifera. A case study from the Saronikos Gulf, Greece, Eastern Mediterranean. Ecological Indicators 60, 611–621. Hyams-Kaphzan, O., Almogi-Labin, A., Sivan, D., Benjamini, C., 2008. Benthic foraminifera assemblage change along the southeastern Mediterranean inner shelf due to fall-off of Nile-derived siliciclastics. Neues Jb. Geol. Paläontol. Abh. 248, 315–344. Renkonen, O., 1938. Statisch-okologische Untersuchungen uber die terrestiche kaferwelt der finnischen bruchmoore. Annales Botanici Societatis Zoologicæ-Botanicæ Fennicæ “Vanamo” 6, 1–231. Rossi, V., Horton, B.P., 2009. The application of subtidal foraminifera-based transfer function to reconstruct Holocene paleobathymetry of the Po Delta, northern Adriatic Sea. J. Foraminifer. Res. 39, 180–190. Samir, A.M., Abdou, H.F., Zazou, S.M., El-Menhawey,W.H., 2003. Cluster analysis of recent benthic foraminifera from the northwestern Mediterranean coast of Egypt. Rev. Micropalaeontol. 46, 111–130. Sgarrella, F., and Moncharmont Zei, M. (1993). Benthic Foraminifera of the Gulf of Naples (Italy) : systematics and autoecology. Boll. Della Soc. Paleontol. Ital. 32, 145–264. Milker, Y., Schmiedl, G., Betzler, C., Römer, M., Jaramillo-Vogel, D., and Siccha, M. (2009). Distribution of recent benthic foraminifera in shelf carbonate 52 environments of the Western Mediterranean Sea. Mar. Micropaleontol. 73, 207–225.

ABSTRACT. Background Mineral staining of buried bone is a diagenetic procedure, which involves mainly Fe and Mn oxides (Stermer et al., 1995; Stathopoulou et al., 2013; Bradfield, 2018). Manganese is usually the most present in soil and can occur in several oxidation states, each resulting in different colouration of the bone surface with which it has come into close proximity. Specifically, reduced manganese will tend to produce darker brown to black stains (Dupras and Schultz, 2014). Iron oxides in the sediment typically result in bone turning a deep chocolate brown colour, while well-drained soils conducive to oxidizing conditions can result in bright red to brown discolourations. The mineral composition of soils, soil solution, unique chemistry and pH play an important role on bone staining (Shahack-Gross et al., 1997). Moist, acidic conditions are conducive to corrosion (Janaway, 2008) and it is in these environments that a variety of bone discolourations are expected. Possible causes of oxide staining may include: 1) microbial activity and more specifically activity of Mn, Fe-oxiding bacteria. The optimal conditions preferred by these bacteria are moist environments that are aerobic with near neutral pH. Manganese origin is often associated with soil humification following a human occupation. The presence of clay minerals is also important, since the bacteria can adsorb on them and use nutrients that also absorb on clay. The bacteria concentrate metals from their environment, most probably from water. The bones themselves may serve as a source of nutrients for the Mn- oxidizing bacteria (Marin Arroyo et al., 2008; Shahack-Gross et al., 1997), and 2) alterations of pH and Eh that may cause precipitation of Fe –Mn oxides. For instance, iron oxides can be produced due to the oxidation of pyrite. Bacterial solubilization and oxidation of iron from pyrite has also been determined. An increase in pH and intensification of oxidizing conditions (associated with dry, well-aerated soils) may favour a change in manganese towards insoluble forms. On the contrary, with a decrease in pH, the manganese may be reduced, increasing its solubility. An increase in the pH can, in turn, be due to burial causes, lack of humidity, the evolution of the soil itself, or other types of causes that may have an anthropogenic origin, such as combustion produced in hearths (Caldeira et al., 2010; Marin Arroyo et al., 2008). The identification of mineral staining at a site is important, as bone discolouration may also be connected to burning. The use of fire within a prehistoric settlement or site is one of the major issues of geoarchaeological research (Asmussen, 2009), as it proves the presence of man. The identification of archaeological burnt bones has commonly been based on changes such as their colour, crystallinity, shape, histology, as well as the presence of cracks and a black char with characteristic chemical properties. The most easily identified colour, indicative of burning, is also black (Shipman et al., 1984). Objectives This paper presents the interdisciplinary study on the origin of “black bones” at the Neolithic lakeside settlement of Dispilio, Greece (5500–3500 BC), where discoloured animal bones have been recovered from a waterlogged and organic soil-matrix containing charcoal, ash and burnt cultural remains. In the past, this has been interpreted as the result of the destruction of the village by fire and abandonment. This study aims to examine whether the colouration of the material at the site can be explained by this theory, through the distinction of burnt vs. oxide stained bones. Material-Methods Forty four (44) groups of fish bones and nineteen (19) mammal bone samples were selected for this study. The fish bones included fragments from the neurocranium, the branchiocranium and the spine (vertebrae, costae, etc) as well as bone parts from the pectoral, pelvic and fin skeleton. The species most represented were Cyprinus carpio and Silurus glanis. The mammal bone samples were shafts of long bones (tibia, humerus, etc), and of metapodials, as well as fragments of short bones. They were pieces not identified to species, and pertained predominantly to smaller animals. Material was mainly chosen based on colour, in an attempt to cover all types of bone discolouration present at Dispilio (light-coloured/yellow to dark-coloured/black), but also the different cultural contexts found at the site (lacustrine phase C, early-pre-destruction and late-destruction) and amphibian phase B (post-destruction layer; terrestrial phase). By means of comparison, two modern bone reference samples were used (NIST bone meal sample Reference material 1486 and an exhumed relatively fresh bovine bone). All bone samples were examined through Optical Microscopy, Scanning Electron Microscopy (SEM), X-ray Microanalysis (EDS), X-ray Diffraction (XRD) - Rietveld Analysis, Infrared Spectroscopy (ATR, NIR) and chemical analyses (ICP-MS). Alterations of histology, mineralogy, chemistry, crystallinity and structural parameters due to diagenesis and/or possible burning are presented and correlated to the intriguing regional geochemical context. Results-Conclusions The various analytical techniques employed on mammal and fish bones did not offer any proof that any of the chosen material is burnt, based on specific features described in relevant bibliography. Rather, all the observed alterations concerning cracking, histology, colour, crystallinity etc. in the samples, could be attributed to diagenesis. Our study showed that bones have certainly been affected by Mn and Fe oxide staining and owe their colour to this procedure. The soil-matrix at the site, which is very rich in charcoal and ash but at the same time waterlogged and organic, may have played a role in bone colouration, in combination with the aforementioned phenomena. Oxide staining is a very common phenomenon in sites that appear rich in organic matter abandoned as a result of consumption activities. With respect to the origin of Mn and Fe in the area and based on the mineral phases traced within the surrounding sediment in the polished sections, it can be suggested that these elements come from the rocks and sediments of the surrounding area. It is also possible that part of the Mn does not have a geological origin, and an anthropogenic source should be considered, namely the accumulation of vegetable and animal organic matter. Ions of the metal could be released during decomposition of the organic matter, and then enter the sediments in which the bones are buried (Marin-Arroyo et al., 2008; Shahack-Gross et al., 1997). Regarding the colour based grouping (dark vs. light-coloured bones), it also corresponded to a number of different diagenetic features. In general, light-coloured bones seem to be less affected by diagenesis and exhibit features concerning chemistry, crystallinity etc, that resemble those of fresh bone, which proves that these bones were buried in a totally different geochemical environment to the dark-coloured ones. On the other hand, fish samples exhibited some different characteristics to those of mammal bones. This can be explained by the different histological structure of fish bones, in terms of increased porosity and thus higher susceptibility to dissolution, degradation and interaction with the surrounding sediment. Concerning the stratigraphy of the studied samples, there does not seem to be a specific diagenetic trend, other than those described based on the colour of the bones. Light-coloured bones, come mainly from phase B which represent the terrestrial part of the site, while dark-coloured material derived from all phases, but mostly C early and C late which represent the waterlogged part. Acknowledgements The authors are indebted to late Prof. G. H. Hourmouziadis for providing access to the material, to Panayiotis Karkanas for geting the project off the ground. Funding was provided by the Wiener Laboratory (American School of Classical Studies at Athens). Thanks are owed to Dr. G. D. Chryssikos and Dr. V. Gionis from the Applied Spectroscopy Laboratory, of the Theoretical and Physical Chemistry Institute at the National Hellenic Research Foundation, for their ideas and specialized knowledge, as well as for the application of vibrational techniques on our material. References Asmussen, B., 2009. Intentional or incidental thermal modification? Analysing site occupation via burned bone. Journal of Archaeological Science 36, 528–536. Bradfield, J., 2018. Some thoughts on bone artefact discolouration at archaeological sites. Journal of Archaeological Science: Reports 17, 500–509. Caldeira, C.L., Ciminelli, V.S.T., Osseo-Asare, K., 2010. The role of carbonate ions in pyrite oxidation in aqueous systems. Geochimica et Cosmochimica Acta 74, 1777–1789. Dupras, T., Schultz, J., 2014. Taphonomic bone staining and color changes in forensic contexts. In: Pokines, J., Symes, S. (Eds.), Manual of Forensic Taphonomy. CRC Press, Florida, 315–340. Janaway, J., 2008. The Decomposition of Materials Associated with Buried Cadavers. In: Tibbett, M., Carter, D. (Eds.), Soil Analysis in Forensic Taphonomy: Chemical and Biological Effects of Buried Human Remains. CRC Press, Florida, 153–201. Marin Arroyo, A.B., Landete Ruiz, M.D., Vidal Bernabeu, G., Seva Román, R., González Morales, M. R., Straus, L.G., 2008. Archaeological implications of human-derived manganese coatings: a study of blackened bones in El Mirón cave, Cantabrian Spain. Journal of Archaeological Science 35, 801–813. Shahack-Gross, R., Bar-Yosef, O., Weiner, S., 1997. Black-coloured bones in Hayonim Cave, Israel: differentiating between burning and oxide staining. Journal of Archaeological Science 24, 439–446. Shipman, P., Foster, G., Schoeninger, M., 1984. Burned bones and teeth: An experimental study of color, morphology, crystal structure and shrinkage. Journal of Archaeological Science 11, 307–325. Stathopoulou, E. T., Theodoropoulou, T. and Phoca-Cosmetatou, N., 2013. Black fish bones in waterlogged deposits: the case of the Neolithic lake settlement of Dispilio, Greece. Archaeofauna 22, 51-74. Stermer, E., Risnes, S., Fischer, P., 1995. Trace element analysis of blackish staining on the crowns of human archaeological teeth. Eur. J. Oral Sci. 104, 253–261.

ABSTRACT. Introduction and Geological setting The Circum-Rhodope Belt (CRB) in Greece comprises the eastern part of Peonias subzone of the Vardar (Axios) Zone. It is a complex imbricated belt that borders the Palaeozoic high-grade crystalline basement of Serbo-Macedonian massif. It mainly consists of Upper Palaeozoic to Mesozoic greenschist-facies metamorphosed sedimentary successions, igneous rocks and ophiolites (Asvesta and Dimitriadis, 2010; Meinhold and Kostopoulos, 2013; and references therein), among them, a Permo-Triassic Silicic Volcano-Sedimentary (SVS) succession that crops out discontinuously in NNW-SSE direction. The SVS succession is an important part of the CRB, as it probably represents the early stages of the opening of a post-Variscan, neo-Tethyan oceanic strand (Vardar -Axios- oceanic basin) which was finely eliminated during some stage of the Tertiary Alpine orogeny (Asvesta, 1992; Dimitriadis and Asvesta, 1993; Asvesta and Dimitriadis, 2010, 2013). The SVS succession is laid stratigraphically between the Permian Examili Formation (terrigenous sediments) and the Triassic Svoula Formation (neritic carbonate sediments). From base to top it comprises mainly rhyolitic to rhyodacitic pyroclastic rocks, aphyric and porphyritic lavas, as well as domes intruded and sills embedded into formerly wet unconsolidated neritic carbonate sedimentary facies forming peperites, hyaloclastites and polymictic epiclastic sedimentary rocks. This facies architecture suggests an acid volcanic activity in a transitional subaerial-coastal to shallow submarine environment, which was still active when the neritic carbonate sedimentation began (Asvesta and Dimitriadis, 2010, 2013). Moreover, minor occurrence of tholeiitic basalts and dolerites (Triassic Rift Basic Volcanics: Asvesta, 1992; Dimitriadis and Asvesta, 1993; Asvesta and Dimitriadis, 2013) are temporally and spatially related with the SVS succession, as they are found interstratified with the Upper Triassic pelagic chert and carbonate sediments of Metallikon and Megali Sterna units as well as in the Akritas rhyodacitic lavas of the SVS succession. Results and Discussion Silicic Volcanic rocks (63 samples) from the SVS succession, outcropping near the villages Akritas, Metallikon, Kolchida, Nea Santa and Sana, were studied geochemically for major and trace elements in order to investigate their origin and geotectonic environment. The rocks (SiO2 range from 62.30 to 85.42 wt.%) are classified predominantly as rhyolites, rhyodacites and much less as dacites (Figure 1a). They are corundum-normative, peraluminous (molar A/CNK ratios range from 0.99 to 1.37), enriched in total alkalis, depleted in MgO and CaO and have high FeOt/MgO ratios. They are enriched in HFS elements, like Zr, Nb and Y. On primordial mantle normalised multi-element spider diagrams (Figure 1b), samples of all areas show similar patterns revealing origin from the same magma. It is indicated that feldspar (negative Ba and Sr anomalies), apatite (negative P anomaly) and Fe-Ti oxides (negative Ti anomaly) were fractionated from the magma. The presence of significant positive Th and Pb anomalies indicates evidence of a significant crustal component in their magma source. In granite discriminate diagram of Whalen et al. (1987), all samples of the volcanic rocks fall almost exclusively in the field of A-type granite (Figure 1c). On the tectonic discrimination diagram (Y+Nb) vs. Rb for granites, the majority of samples lie in the within-plate granite field but all the samples straddle at the triple junction boundary of the within-plate, volcanic arc and syn-collision granites (Figure 1d) that is the post-collision granite field (Pearce, 1996). This also provides support for an A-type character magma, as A-type is considered emplaced in post-collisional or within plate settings; i.e., an extensional environment (Whalen et al., 1987; Eby, 1992). Eby (1992) divided the A-type granitoids into two groups (A1 and A2). Granitoids that are associated with true anorogenic (within plate) settings and interpreted as differentiates of basaltic magma derived from an OIB-like source (A1 group: Y/Nb<1.2), and granitoids that are often emplaced in post-collisional, post-orogenic settings and were derived from the subcontinental lithosphere or lower crust (A2 group: Y/Nb>1.2). All samples of the studied silicic volcanic rocks surpass the 1.2 value of Y/Nb ratios (1.87-4.75, average 3.36) and plot in the A2 granite field (Figure 1e) on the (Nb-Y-Ce) discrimination diagram of Eby (1992), implying dominant crustal magma sources derivation and emplacement in a post-collisional environment. Furthermore, Ce/Nb vs. Y/Nb discrimination diagram is used to estimate possible genetic links of the A-type granitoids with crustal sources or mantle-derived magmas (Eby, 1992). In this diagram, the rhyolite samples plot well into the field for rocks derived by crustal anatexis, characteristic for A2 group (Figure 1f). The sources, from which these granitoids were extracted, were originally formed by subduction or continent-continent collision (Eby, 1992). The role of mantle-derived mafic magmas, to provide heat and/or material, seems essential in the generations of the A-type granitoid melts (Eby, 1992). The investigated silicic volcanic rocks have relatively high magma temperatures (average Zr saturated temperature: Tzr=886°C) indicating that the crustal source rocks should have been underplated and heated by mantle-derived mafic magmas. The presence of the nearby minor outcrops of tholeiitic basalt and dolerite with a transitional MORB to within-plate character (Triassic Rift Basic Volcanics: Asvesta, 1992; Dimitriadis and Asvesta, 1993; Asvesta and Dimitriadis, 2013) provides supportive evidence for the existence of underplating magmatism. Furthermore, limited magma mixing microtextures in dacites and mafic microgranular enclaves in rhyolites of Metallikon area support the coexisting mafic and felsic volcanism. The Triassic volcanism in CRB was in fact bimodal (A2-subtype rhyolites-dacites and minor tholeiites). Moreover, A2-subtype post-collisional granites (Arnea and Kerkini suits) of Late Permian to Early Triassic age have intruded the nearby western Vertiskos unit of Serbo-Macedonian massif (Poli et al., 2009) and are likely the deep level equivalents of the Permo-Triassic volcanic rocks studied here (Poli et al., 2009; Asvesta and Dimitriadis, 2010).

Figure 1. (a) Zr/TiO2 vs. Nb/Y classification diagram (Winchester and Floyd, 1977), (b) primitive mantle normalised trace element patterns (normalisation values after Sun and McDonough, 1989), (c) (K2O+Na2O)/CaO vs. (Zr+Nb+Ce+Y) discrimination diagram (Whalen et al., 1987), (d) tectonic discrimination diagram (Y+Nb) vs. Rb for granites, post-COLG=post-Collision Granites (Pearce, 1996), (e) Nb-Y-Ce ternary diagram (dashed line corresponds to Y/Nb ratio of 1.2) (Eby, 1992), (f) Ce/Nb vs. Y/Nb discrimination diagram, OIB: oceanic island basalts, black cross labelled C: average crustal composition, IAB: island arc basalts, MORB: mid-ocean ridge basalts (Eby, 1992).

Conclusions The Permo-Triassic Silicic Volcanic rocks from Circum-Rhodope Belt are A2-subtype rhyolites-dacites and are probably the extrusive facies of the coeval and similar geochemically Arnea and Kerkini granites. It is suggested that silicic volcanism in CRB was evolved during a post-collision extensional stage of a Variscan progeny, leading to attenuated continental lithosphere and continental rifting during the Permo-Triassic which created the Vardar (Axios) oceanic strand. Silicic magma was produced by crustal anatexis of Serbo-Macedonian basement (Vertiskos unit) that was underplated and heated by mantle-derived mafic magma, represented by the minor dolerites and basaltic extrusions in the CRB. References Asvesta, A., 1992. Magmatism and associated sedimentation during the first stage of the opening of the Vardar oceanic basin in Triassic times. Ph.D. Thesis, Department of Geology, Aristotle University of Thessaloniki, Greece, 439 p. (in Greek with English summary). Asvesta, A., Dimitriadis, S., 2010. Facies architecture of a Triassic rift-related Silicic Volcano-Sedimentary succession in the Tethyan realm, Peonias subzone, Vardar (Axios) Zone, northern Greece. J. Volcanol. Geotherm. Res. 193, 245-269. Asvesta, A., Dimitriadis, S., 2013. Magma-sediment interaction during the emplacement of syn-sedimentary silicic and mafic intrusions and lavas into and onto Triassic strata (Circum-Rhodope Belt, northern Greece). Geologica Carpathica 64(3), 181-194. Dimitriadis, S., Asvesta, A., 1993. Sedimentation and magmatism related to the Triassic rifting and later events in the Vardar-Axios zone. Bull. Geol. Soc. Greece XXVIII(2), 149-168. Eby, G.N., 1992. Chemical subdivision of the A-type granitoids: petrogenetic and tectonic implications. Geology 20, 641-644. Meinhold, G., Kostopoulos, D.K., 2013. The Circum-Rhodope Belt, northern Greece: Age, provenance, and tectonic setting, Tectonophysics 595-596, 55-68. Pearce, J.A., 1996. Sources and settings of granitic rocks. Episodes 19, 120-125. Poli, G., Christofides, G., Koroneos, A., Soldatos, T., Perugini, D., Langone, A., 2009. Early Triassic granitic magmatism – Arnea and Kerkini granitic complexes – in the Vertiskos unit (Serbo-Macedonian massif, north-eastern Greece) and its significance in the geodynamic evolution of the area. Acta Vulcanologica 21(1-2), 47-70. Sun, S.-S., McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic basalts: Implications for mantle composition and processes. Geol. Soc. London, Spec. Publ. 42, 313-345. Whalen, J.B., Currie, K.I., Chappell, B.W., 1987. A-type granites: geochemical characteristic, discrimination and petrogenesis. Contrib. Mineral. Petrol. 95, 407-419. Winchester, J.A., Floyd, P.A., 1977. Geochemical discrimination of different magma series and their differentiation products using immobile elements. Chem. Geol. 20, 325-343.

ABSTRACT. In sedimentary studies one of the physical properties of the examined samples is grain roundness; a critical parameter providing information about the depositional environment and the physical processes that the material has undergone since its deposition. This paper describes an attempt to provide an automatic and accurate method to measure roundness of clastic particles from sediments. The technique, developed at the Marine Geology laboratory of HSGME, is based on the Waddel (1935) methodology, traditionally applied through laborious microscopic examination. To provide an automatic and out of the box routine Model Building tools and script development using Python Libraries in an ArcMap environment were involved. GIS was chosen as a practical solution for data elaboration and mapping both in marine and terrestrial sedimentary studies.

ABSTRACT. The Mesohellenic Basin (MHB) is a synorogenic molasse-type basin of NW Greece active from the late-Eocene (late Lutetian) through the mid-Miocene (Langhian). The MHB has been studied since the late 19th century with few mentions of its fossil content (Wielandt-Schuster et al., 2004); in the 1950’s Brunn (1956) presented a synthetic work that analyzed all the characteristics of the basin. In the present study, a multidisciplinary paleoenvironmental approach, based on sedimentological and paleontological analyses, is attempted in newly studied sections. Particularly, the material comes from two new sections and one new locality of the greater Grevena area in NW Greece. One section and locality are of late Oligocene age (Chattian), and one section is of the early Miocene age (Aquitanian). The sections belong to Eptachori and Pentalofo formations (Zelilidis et al. 2002), and are mainly composed of fine marls, marly sands to conglomerating sands. Most of the fossiliferous beds are fine-grained, with only one coquina bed found during our investigation in the known Dotsiko section (Wielandt-Schuster et al., 2004). Fossil content in the region include mollusks, benthic foraminifers, ostracods and wood fragments. The detailed sedimentary facies analysis together with the taxonomic analysis of mollusks, benthic foraminifers and ostracods has yielded two different environments, one of brackish-mudflat character, and one where shallow marine conditions prevailed. For mollusks, new occurrences of 17 species are noted in the Aquitanian, as well as 5 new species (Thivaiou et al. in press). For the Oligocene, three species of bivalves are reported for the first time from Dotsiko section of Wielandt-Schuster et al. (2004), as well as two species of micromorphic gastropods. The gastropod species Bellatara lozoueti Harzhauser, 2004 is found in shallow marine assemblages of three Oligocene locations of the studied area, in addition to the original location of Dotsiko village (Harzhauser, 2004). Species of Terebralia Swainson, 1840 infer proximity to mangrove environments and (Houbrick, 1991; Raw et al., 2017; Reid et al., 2008). In the study area, two occurrences are noted, one in the Chattian and one in the Aquitanian. Benthic foraminifers and ostracods provide stronger support of differences between the brackish-mudflat assemblage and the shallow marine assemblage, as their taxonomic diversity and relative numbers vary. They also are reflecting well the fluctuating environments especially for the Aquitanian section. Interestingly, the ostracod assemblages also point towards the presence of mangrove environments in the same section. The combined results, help retrace the sea level fluctuations and add information to the evolution of the MHB, for example the details of the subsidence curve of (Ferrière et al., 2004). Lastly, the analysis of fossil wood fragments has shown transportation and strong boring from Teredo Linnaeus, 1758 for specimens collected in the Oligocene. Samples from the early Miocene found within the brackish-mudflat assemblage correspond to an “evergreen Quercus type” wood (Fagaceae), inferring such nearby forests. In summary, the present study has brought new information relative to sea-level changes that occurred in the MHB, with changing environments between shallow marine and bracksish–coastal mudflats.

ABSTRACT. Dachstein-type loferitic facies in the Upper Triassic-Lower Jurassic carbonate platform of the Eastern Greece Zone

ABSTRACT. The geological mapping on the Sofrana insular complex, in the SE Aegean Sea, sheds some light on the geological history gap on that part of the Carpathian Sea, which extends among Astypalea, Karpathos and Cretan basin. We recognize two tectono-stratigraphic units that correlated with the geotectonic units of the external Hellenides on the adjacent islands, such as a parautochthonous unit at the base, tectonically overlain by an upper unit as follow: A) The parautochthonous unit of the insular complex consists, from base to top, of a) basal recrystallized or dolomitic limestones and dolomites, overlain by a succession of fine-grained to mixed with big clasts, locally dolomitized, of grainstones, packstones and wackestones, as well as of Thaumatoporella bindstone, similar to the Ionian “Pantokrator” facies, of Late Triassic-Middle Lias age, occurring on the islets of Mikro Sofrano, Divounia and Astakida, and having a thickness up to 600m; b) Upwards, Upper Lias to Middle Jurassic platy to thin-platy, white, pelagic to sublithographic limestones occur, of mudstone texture, like the Ionian Sinies facies, 100m approximately thick, in the islets of Mikro Sofrano and Astakida, and c) at the top of the islets of Mikro Sofrano, Karavonisia, Avgo, Sial, Astakida and Astakidopoulo, an Upper Jurassic – Cenomanian sequence occurs, significantly recrystallized, with thin-to-mid-bedded, multifolded, green, pelagic limestones bearing silex intercalations and nodules, similar to the Ionian Vigla limestone facies, over than 500m in thickness. B) The tectonically overlying upper unit consists, from base to top, of the following distinguished members: a) Medium- to thick-bedded, fine- to coarse-grained and brecciated limestones, slightly recrystallized, with rudist and coral fragments and, towards the base, micritic with bioclasts, of Cenomanian age. They occur on the islands Megalo Sofrano, Astakida (klippe) and Chamili, having a 500m apparent thickness; b) On Megalo Sofrano and Chamili islets develop upwards micritic to fine-clastic limestones (mudstones and wackestones), of early Senonian age, tending to emerge. The thickness is 100m approximately; c) At the top on Megalo Sofrano and Chamili islets develop Upper Campanian bioclastic limestones, with fine- to coarse-grained packstones, characterized by mild recrystallization, of 200m approximate thickness; d) Paleocene-Middle Eocene nummulitic bioclastic limestones, 150m approximately thick, occurring on the last two islets and, finally, e) a Middle (?) - Upper Eocene flysch sequence, with thin- to medium-bedded, fine- to medium-grained turbiditic sandstones with foliated argillite intercalations occurs solely on the Megalo Sofrano islet, exceeding 50m in thickness. The above stratigraphy and stacking order of the Sofrana insular complex consists of a parautochthonous unit, which outcrops in Mikro Sofrano, Karavonisia, Avgo, Sial, Divounia, Astakida and Astakidopoulo islets, and is correlated to the Ionian geotectonic zone. Besides, the upper tectonic unit, occurring in Megalo Sofrano, Chamili and Astakida (as klippe) is correlated to the Gavrovo-Tripolis geotectonic zone and more precisely to the Gavrovo sub-zone. This stacking setting, characterized by a thin-skinned thrusting, would occur in the late Miocene times, during the southward detachment of the Plattenkalk unit (Crete - Kassos - eastern Rhodes) that is implicated, in turn, in an inter-thrusting under the Ionian zone (Sofrana insular complex) and over the pre-Apulian zone (Ro - Strongyli – Kastellorizo complex).

Acknowledgements Τhis work is dedicated to the Hellenic Navy and especially to the Officers and crew of the Oceanographic Vessel Nautilus during 2008-2009.

ABSTRACT. Background Corinth Isthmus is one of the fastest extending regions worldwide as it is a highly active extensional tectonic environment (Briole et al., 2000). More than 40 faults can be recognized along the Corinth Canal most of them being normal and oblique normal with fault planes dipping westwards and eastwards from the central horst, towards the Corinth and Saronic Gulfs respectively (Freyberg, 1973, Papanikolaou et al., 2015). Although the depositional patterns of the sedimentological sequences in Corinth Canal are of great interest as six transgressive-regressive cycles were recognized by Collier (1990), there are few detailed palaeoenvironmental studies based on micropalaeontological evidence (e.g. Krstic and Dermitzakis 1981; Papanikolaou et al., 2015; Pallikarakis et al., 2018). Objectives Purpose of this study is to contribute with detailed micropalaeontological evidence to the reconstruction of the depositional environments of the sedimentary sequence exposed in the central part of Corinth Isthmus. Methods The study area is located at the central part of Corinth Isthmus and includes the sedimentary sequence exposed at about 70 m elevation along the north side of the Corinth Canal (Fig. 1). The sequence is consisted of two different formations from the bottom to the top: about 10 m of beige marls and yellow sandy marls and about 5 m of sandstones and conglomerates. The two formations are bounded by an unconformity surface. Just before the unconformity, the marly sequence ends up with a sandy bed rich in Cladocora caespitosa stems and bivalves and it was dated at MIS11 by Pierini et al. (2016). A total of 22 samples were collected from the marls and the C. caespitosa bed for micropalaeontological analysis. The samples were disaggregated with a 5% H2O2 solution, washed over 0.125 mm mesh sieves, and the residues were oven-dried at approximately 40 °C. Dried material was splitted and microfossils (ostracods and benthic foraminifera) were hand-picked, identified and counted and a detailed quantitative and qualitative micropalaeontological analysis was performed. Additionally, two samples have been prepared for nannofossil biostratigraphy.

Results and Discussion Ostracods are the most abundant group in most of the samples, while benthic foraminifera are dominant in the samples from the bed with C. caespitosa. A total of 17 ostracod species were identified. The most common and abundant taxa in all the marly and sandy marly layers are the mesohaline Cyprideis torosa, Cyprideis sp., Tyrrhenocythere amnicola, Loxoconcha aff. L. elliptica, Euxinocythere schuldtae and the fresh water-oligohaline species Candona neglecta, C. angulata. A total of 28 benthic foraminiferal species were identified; specimens are considered transported when showing scarce presence and bad state of preservation. The euryhaline taxa Ammonia beccarii, A. tepida and Elphidium spp. are considered in situ and are present in low numbers in most of the marly layers. The combined study of ostracods and benthic foraminifera demonstrated four main micropalaeontological assemblages: Oligohaline assemblage: Includes high abundances of C. torosa and Candona spp. There are not benthic foraminifera present. This assemblage indicates a closed lagoonal environment with very limited communication with the sea and significant fresh water input. Mesohaline assemblage: Characterized by the presence of mesohaline ostracod taxa and very low frequencies of euryhaline benthic foraminifera. This assemblage indicates a closed lagoonal environment with limited communication with the sea and fresh water input. This is the most frequent assemblage in the studied samples. Polyhaline assemblage: Identified by the presence of both mesohaline and shallow marine ostracod taxa (Aurila convexa, Loxoconcha spp., Xestoleberis spp., Leptocythere multipunctata). Accordingly, benthic foraminifera present their higher diversity and abundance in this open lagoonal environment represented by euryhaline and marine taxa: Ammonia spp., Elphidium spp., Asterigerinata mamilla, Cibicides lobatulus, C. refulgens, Cancris auriculus and Neoconorbina sp. Coastal open marine assemblage: Characterized by high frequencies of coastal marine ostracod and benthic foraminifera taxa. It is present only in the samples from the sandy bed with C. caespitosa and bivalves. Represents a normal salinity-high energy, shallow-coastal open marine environment. Conclusions The distribution patterns of the identified ostracod and foraminiferal assemblages combined with the sedimentary facies reflect the various depositional environments which alternate along the studied section. Consequently, the lower formation (beige marls and yellow sandy intercalations) of the sedimentary sequence exposed at the central part of Corinth Isthmus corresponds to a brackish lagoonal environment with salinity alternations due to the communication with the sea (closed-, semi-closed-, open-lagoon) and the fresh water input. At the top of this formation a sandy bed rich in macro- and micro- fossils indicates a radical environmental change: the opening of the lagoon and the establishment of a shallow marine coastal environment, expressing the beginning of a regressive circle. References Briole, P., Rigo, A., Lyon-Caen, H., Ruegg, J.C., Papazissi, K., Mitsakaki, C., Balodimou, A., Veis, A., Hatzfeld, D., Deschamps, A., 2000. Active deformation of the Corinth rift, Greece: results from repeated Global Positioning System surveys between 1990 and 1995. J. Geophys. Res. Solid Earth, 21, 25,605–25,625. Collier, R.E.L., 1990. Eustatic and tectonic controls upon Quaternary coastal sedimentation in the Corinth Basin, Greece. Journal of the Geological Society, 147(2), 301–314. Freyberg, V., 1973. Geologie des Isthmus von Korinth. Erlangen Geologische Ablhandlungen, Heft 95. Junge und Sohn, Universitats Buchdruckerei Erlangen (183 pp., in German). Krstic, N., Dermitzakis, M.D., 1981. Pleistocene fauna from a section in the channel of Corinth (Greece). Annales Geologiques des Pays Helleniques, 1e Serie, 30(2), 473–499. Pallikarakis, A., Triantaphyllou, M., Papanikolaοu, I.D., Dimiza, M.D., Reicherter, K., Migiros, G., 2018. Age Constraints and Paleoenvironmental Interpretation of a Borehole Sedimentary Sequence at the Eastern Part of Corinth Isthmus, Greece, Journal of Coastal Research, 34(3), 602-617. Papanikolaοu, I.D., Triantaphyllou, M., Pallikarakis, A., Migiros, G., 2014. Active faulting at the Corinth Canal based on surface observations, borehole data and paleoenvironmental interpretations. Passive rupture during the 1981 earthquake sequence? Geomorphology, 237, 65–78. Pierini, F., Demarchi, B., Turner, J., Penkman, K., 2016. Pecten as a new substrate for IcPD dating: The quaternary raised beaches in the Gulf of Corinth, Greece, Quaternary Geochronology, 31, 40-52.

ABSTRACT. International Ocean Discovery Program (IODP) Expedition 381 was operated as a Mission Specific Platform onboard the industry drilling vessel Fugro Synergy between October and December 2017 in the Gulf of Corinth, Greece. The objective of the expedition was to retrieve a record of early continental rifting and basin evolution from the Corinth rift in order to: • obtain high spatial and temporal resolution records of the dynamics of the rifting process and its evolution, • study the interaction of climate and tectonics on sedimentary and surface processes in a rift zone, • generate a new high-resolution Quaternary paleoenvironment and palaeoclimate record from an active basin, and • to improve regional hazard assessments in one of the most seismically active regions of Europe. The Corinth Rift, one of Europe’s most seismically active areas, is a region of rapid, localised extension, exhibiting today some of the highest extension rates in the world. The young rift (~5 Ma) has evolved in 3 main phases identified by integration of onshore depositional records and offshore seismic stratigraphy (e.g. Leeder et al., 2002; Lykousis et al., 2007; Ford et al., 2013; Nixon et al., 2016; Gawthorpe et al., 2017). Corinth’s high rates of tectonic activity, high sediment fluxes, closed drainage system and preservation of the syn-rift record make it a unique laboratory for the study of extension, sedimentation and paleoenvironment in a young rift. During IODP Exp. 381, three sites (Figure 1) located along the Gulf of Corinth, were drilled, sampled and logged. A total of 1645 m of sediments were retrieved from 1900 m of cored section (an average recovery of 86%), sampling in high resolution the syn-rift sedimentary sequence back to ~1.5 Ma or more. During the onshore phase that took place in Bremen, Germany in February 2018, 35 scientists from 10 countries described, sampled and analyzed the recovered deposits and data (McNeill et al., 2019a). Cores recovered together provide (1) a longer rift history (Sites M0078 and M0080), (2) a high resolution record of the most recent phase of rifting (Site M0079), and (3) the spatial variation of rift evolution (all sites; Shillington et al., 2019; McNeill et al., 2019a). The deposits contain a rich and complex record of changing sedimentation, sediment and pore water geochemistry, and environmental conditions from combined micropaleontological and palynological assemblages. This is the longest and highest resolution sedimentary record from a young extensional basin at the point of connection to the global oceans, and it provides the first constraints on the age of the full rift sequence, syn-rift stratigraphy, rates and timings of rift tectonic processes, sediment fluxes and basin environmental conditions. First results produced during the onshore phase confirmed the basin environment fluctuations between marine conditions during eustatic highstands and isolated conditions during eustatic lowstands - when the basin was cut off by basin-bounding sills. During interglacials, when the basin was connected with the Mediterranean Sea, sedimentation rates were lower, and bioturbation and organic carbon concentration higher. During glacials, the basin was isolated from the ocean, and sedimentation rates were 2 to 7 times higher than during interglacials (McNeill et al., 2019b). The higher sedimentation rates during glacials may signify increased erosion and basin sediment influx driven by the decrease and change of vegetation cover during the glacial, as also recorded in other existing long Mediterranean palaeovegetation records (Sadori et al., 2016; Tzedakis et al., 2006). Post-cruise analysis of the IODP Exp. 381 data will allow the investigation of the relative roles of and feedbacks between tectonics, climate, and eustasy in sediment flux and basin evolution. Furthermore, the Corinth rift boreholes will provide the first long Quaternary record of Mediterranean-type climate in the region. The potential range of scientific applications for this unique data set is very large, encompassing tectonics, sedimentary processes, paleoenvironment, paleoclimate, paleoecology, geochemistry, and geohazards.

ABSTRACT. Several episodes of magmatic activity characterize the Paleogene-Quaternary geological history of Greece. Set in a back-arc geotectonic environment, this activity is the result of the south-southwestward migration of the post-collisional geodynamic settings of the Alpine orogeny (Agostini et al., 2010). The undergoing widespread regional extension of the geodynamical Northern Aegean region has been active since Eocene-Early Miocene and has resulted in the formation of distinct magmatic rock groups of plutonic to volcanic origin (Melfos and Voudouris, 2017; Sakellariou and Tsampouraki-Kraounaki, 2019). Specifically, the Cenozoic rocks of volcanic origin comprise: a) the Lower to Middle Miocene shoshonites and adakites of the northeastern Aegean region, b) the Middle Miocene to Pliocene volcanic rocks of the southeastern Aegean region, c) the Pliocene-Quaternary volcanic rocks of the northwestern Aegean region, d) the lamproites and alkaline basalts of the Aegean Islands and western Anatolia, and e) the subduction-related volcanic rocks of the southern Aegean volcanic arc (Pe-Piper and Piper, 2007). The Pliocene to Quaternary volcanic rocks at Almopia, Charopo (Sitsi-Kamen), Doirani, Strymonikon, Euboecos, Psathoura, Vlichades, and Mikrothive belong to the group of the northwestern Aegean region (Vougioukalakis et al., 2004; Pe-Piper and Piper, 2007). This refer area corresponds with the geodynamical Northern Aegean region where the North Anatolian trough fault zone has a major role in structural control dynamics. According to Pe-Piper and Piper (2007) these rocks are the result of a slab tear at the depth of 300 km spanning from Albania to the Gulf of Corinth. The present study focuses on the Almopia and Charopo trachytic to rhyolitic rocks which are the northernmost volcanic rocks of Pliocene to Pleistocene age found in northern Greece (Fig. 1) (Pe-Piper and Piper, 2007). They are located at Voras mountains and Aridaia plain and at the northern part of the Strymon basin respectively and their occurrences are strongly structurally controlled (Maratos, 1966; Vougioukalakis et al., 2004). At the area of Voras, the volcanic activity initiated at 6.5 Myr and terminated at 1.8 Myr shifting from east to west in an area of approximately 70 km2. Dacites, trachytes, latites, and andesites and a rhyolitic dome describe the Voras volcanic rocks (Vougioukalakis et al., 2004). In addition, volcanic tuffs and lapilli deposits cover large areas both around these rocks and Aridaia plain (Vougioukalakis et al., 2004). The Quaternary Charopo (Sitsi-Kamen) volcanic outcrops are located near Charopo village covering an area of approximately 12 km2 (Maratos, 1966). Rhyolitic tuffs constitute the main volcanic rocks at Sitsi-Kamen, while lavas are scarce at the surface (Maratos, 1966). The Pliocene-Quaternary hydrothermal activity is documented by the present day low-enthalpy geothermal fields occurring in both areas (Karydakis et al., 2005; Lambrakis et al., 2014). Geological mapping at both areas has revealed the significant relation between the volcanic activity and the regional structural control mechanisms (Maratos, 1966; Vougioukalakis et al., 2004). Both regions are characterized by limited fault zones exhibiting NW-SE, NNW-SSE, and NE-SW orientations. Nevertheless, NE-SW and E-W trending remarkable fault zones highlight the predominant structural settings at the Voras and the Sitsi-Kamen areas, respectively. At Almopia region, the Voras and Aridaia volcanic activity were structurally controlled by several fault zones fragmenting the metamorphic rocks of the Almopia Subzone (Axios Zone) at the footwalls of the North Almopia-Promachi and South Almopia fault zones. The volcanic material at Charopo was extruded through the fault zone defining the border between the metamorphic rocks of the Rhodope Massif and the Quaternary sediments of the Strymon basin (Kastanoussa-Petritsi fault) (Caputo and Pavlides, 2013). One of the most reliable and accurate ways of determining the neotectonic activity is satellite geodesy, based on permanently installed GPS/GNSS stations. Regarding the study area of Voras, 12 different stations record the primary geodetic data, including the east and north velocity components, while the corresponding stations, collecting geodetic data for the wider Sitsi-Kamen region, are totally 15. It is mentioned that the aforementioned data was collected for the seven-year time period 2008 – 2014, while the recording was implemented every 30 seconds in a daily basis. The reference frame of geodetic data is European Terrestrial Reference Frame 2000 (ETRF2000) that is coincident with the stable part of the Eurasian Plate. Concerning the data processing, the triangulation method was applied in order to extract a series of parameters (results), revealing information about the neotectonic and geodynamic setting. The principal of the triangulation method is based on the combination of the primary geodetic data of three different GPS/GNSS stations, forming a triangle (each station is located on a triangle vertex), while the use of the triangle medians leads to the estimation of the triangle centroid (Lazos et al., 2018). The implementation of the primary geodetic data into equations, expressing the surficial deformation, results in an extraction of parameters for the triangle centroid. The calculated parameters are the following: 1) maximum horizontal extension, b) minimum horizontal extension, c) area strain and d) rotation (http://www.unavco.org/). Based on the combinations of the GPS/GNSS stations of the study area, 190 different triangles were constructed (Figure 1), while the aforementioned parameters were calculated for each triangle centroid. The extracted parameter values were geostatistically processed in a grid pattern in order to be distributed throughout the study area. The analysis of the parameters shows that the volcanic rocks within the two study areas are directly associated with the active tectonics of the broader area. In particular, the combination of the maximum and minimum horizontal extension values confirms the regional extensional regime which favored the extrusion of the volcanic rocks. Furthermore, the area strain parameter reveals the dilatation, related to the dominant extension of the study areas. Regarding the rotational regime, the counter-clockwise rotation dominates in both areas (approximately 67% of the triangle centroids show counter-clockwise rotation) in contrast with the general clockwise rotational regime of Northern Greece. The transition from the clockwise to the counter-clockwise rotational regime documents the neotectonic activity of the study area, related to the volcanic rocks presence. In conclusion, the Pliocene-Quaternary volcanic activity of northern Greece is directly associated with the extensional regional neotectonic setting.

ABSTRACT. Peloponnese area is in the broader South Aegean region, one of the most tectonically active regions in eastern Mediterranean. Peloponnese exhibits a profound extensional regime, which caused crustal thinning and the evolution of multiple tectonic windows. This extension has been ongoing in the neotectonic period as well (Papanikolaou et al., 1988), forming three major NNW – SSE trending normal fault zones at its southern part (largely controlling Messiniakos, Lakonikos and Argolikos Gulfs), while its northern part is deformed by primarily NW-SE and E – W trending normal fault zones, associated mainly to the tectonic activity of the Corinth Gulf. The area undergoes active deformation, as documented by several seismic events, such as Alkyonides (1981, Mw 6.7), Kalamata (1986, Mw 5.9), Aigion (1995 Mw 6.4) in 1995 and Andravida (2008, Mw 6.4) earthquakes (Jackson et al., 1982; Papanikolaou et al., 1988; Roumelioti 2004; Koukouvelas et al., 2010; GreDaSS Pavlides et al., 2010). One of the most reliable ways of estimating the level of active deformation of an area is Satellite Geodesy, based on permanently installed GPS/GNSS stations and collecting geodetic data (specifically East and North velocity components of the station). Data processing is then implemented by dedicated software packages (UNAVCO), leading to the quantitative and qualitative determination of the uppermost crustal deformation of the study area. Primary data from 59 GPS/GNSS stations were used for extrapolating the deformation pattern of the broader Peloponnese area. They consist of timeseries for seven consecutive years (2008 – 2014), while the data analysis was carried out using 30-sec daily GPS observations. The reference frame of the geodetic data is the European Terrestrial Reference Frame 2000 (ETRF2000), which is coincident with the stable part of the Eurasian plate. Two main sets of methodologies were applied on the collected datasets. The first method is based on a triangulation process, taking into account the data of three different stations, which form a different each time triangle. Each station is located on a triangle vertex and is characterized by a specific velocity value, recorded for the aforementioned time. The intersection of the triangle medians defines the triangle centroid, which is then used as the centre of an inner, inscribed circle, expressing the initial and undeformed triangle. Taking into consideration the motion of the GPS/GNSS stations, which is imprinted on the corresponding velocity vectors of each station, the inner circle is morphed into an ellipse. By using equations, combining the major and minor axes of the inner circle and the ellipse, respectively, a series of parameters related to strain assessment can be calculated. The estimated parameters are: a) maximum and minimum horizontal extension, b) total velocity, c) maximum shear strain, d) area strain and e) rotation. In the frame of this study, 932 different triangles were taken into account, using the 59 permanently installed GPS/GNSS stations (Figure 1). Using the parameters from the first stage a second set of methodologies is implemented, leading to interpolation of missing or incomplete data. Interpolation is a reliable way of geostatistical process, as the distribution of each parameter throughout the study area is calculated with an acceptable confidence range. The geostatistically extracted parameters provide information leading to the interpretation of the neotectonic and the geodynamic setting of the study area. The maximum and minimum horizontal extension parameters are identifying indicators of the extensional and compressional regime in a study area, respectively. The interpolated results show maximum horizontal extension values concentrated at the broader area of Corinth Gulf, as well as the northwestern part of Peloponnese, effectively the meisoseismal area of the 2008 Andravida earthquake sequence, which is contained in the recoding period. Furthermore, high maximum horizontal extension values are observed at the southwestern part of Peloponnese, probably related to offshore faults, located further to the West. Nevertheless, the maximum extension values of the study area, with the exception of the aforementioned areas, are generally low, indicating a rather tectonically quiescent area (Figure 2). Similarly, the main concentration of minimum extension values (i.e. associated with compression) is again located near the epicentral area of the Andravida earthquake. The concurrent maximum extension and maximum compression values are in good agreement with the focal mechanisms of the main event, which attribute it to the reactivation of a deep strike-slip fault. The total velocity is associated to the motion and therefore the geodynamic evolution of the study area. The statistically processed results show an increase of total velocity values from the north-northeastern part to the south-southwestern part of Peloponnese area. These results are comparable and compatible with the general geodynamic setting of the area, as the south-southwestern part of Peloponnese is closer to the subduction zone, extended southwestwards into the offshore area, where African plate is subducted beneath the Eurasian one; it is therefore expected that it is deformed at a higher rate. The maximum shear strain is associated to the deformation of the upper crust, caused by seismic, landslide or creeping phenomena. The areas where the highest values of maximum shear strain are observed are the same with the ones where maximum horizontal extension is observed. The area strain expresses the dilatation and the compaction of the area, associated to extension and compression, respectively. Based on this parameter, a general extensional regime can be identified, while compressional effects are limited and located at the western part of the study area, where the transition from an extensional to a compressional regime is evident from other indicators (geological, structural, seismic, etc.). In general, the low to medium area strain values are compatible with a low activity character of the mainland Peloponnese area. Finally, estimation of the areal rotation can indirectly contribute to the knowledge of the recent geodynamic evolution of area. To this end, the rotation pattern was modelled for three periods (1, 5 and 10 Myr BP), showing a dominant clockwise rotation of the study area. The results of the rotation analysis are preliminary in adequately good agreement with palaeomagnetic data for the broader area (Lazos et al., 2018).

ABSTRACT. In this paper, the dating of Petousi-Souli fault zone (PSFZ) is being studied through a chemical analysis of the rock varnishes which identified in the outer fault surface. Several attempts have been made to identify the ages of geological and tectonic phenomena that develop on the surface of the earth. Other times using absolute dating methods, such as Radiocarbon dating (14C) and Luminescence dating, and others through the use of more qualitative analyzes which, although they lag behind in accuracy, outweigh the speed at which the result is obtained. Such a method is the dating from the observations and the chemical analysis of rock varnishes. Methods The methodology applied to determine the ages of Petousi-Souli fault zone is based on the chemical analysis of rock varnishes with the methods from Dorn (1983; Eq. 1) and the calibration of Nobbs and Dorn (1988; Eq. 2): R_C=((〖Ca〗^(2+)+K^+))⁄〖Ti〗^(4+) (1) where, Ca2+: is the percentage concentration of Calcium (%), Κ+: is the percentage concentration of Potassium (%), and Ti4+: is the percentage concentration of Titanium (%). T=e^((16.218-R_C)/1.137) (2) where, T: is time and RC: is the cation-ratio, resulting from above equation (2). It is a method that has been applied in many areas of the world and especially in petroglyphs, using either a Scanning Electron Microscope or Portable X-Ray Fluorescence. More specifically, in this study the chemical analysis was applied using the EDX POCKET III P730 - QUALITEST XRF mobile spectrometer. Study Area As the study area determined the PSFZ, which located on the central part of northwestern Greece (Fig. 1A). The PSFZ features one of its largest tectonic structures, of a total length of approximately 36.5 km, generally trending E-W, with a southern inclination. The Petousi-Souli fault zone constitutes the largest fault zone of northwestern Greece, while forming at the same time a natural boundary between its northern and southern part. It is classified as active because of its intense morphology and the impressive surface trace consisting of well-preserved fault surfaces which has deep and well-marked striations and canellures (Fig. 1B and C).

Figure 1. (A) Study area and (B and C) field photographs of the PSFZ surfaces in the area of Souli.

This tectonic structure has caused the displacement of pre-existing structures, such as the synclines and anticlines formed during the Alpine fold, as well as recent Quaternary deposits (Ntokos, 2017a, 2018a). It has affected the morphology and relief of a large area, while a typical example of the displacements it has caused can be found in the syncline structure of Voutsaras, which is transversely intersected in the middle, by the Petousi-Souli fault. The Voutsaras syncline seems to present a displacement in the order of 2 km to the east, while the displacements of the geological boundaries, along the length of the fault’s trace, often exceed 4 km. The western and eastern ends of the Petousi-Souli strike-slip active fault feature a series of minor normal and strike-slip active faults, running in a parallel direction to the orientation of the fault, whose high concentration is similar to an enechelon layout, which is typically observed in strike-slip zones. Observations show that this tectonic structure fans out into numerous smaller branches, typical in cases on strike-slip faults (imbricate fans). Since these faults are consistently oriented from E-W to NE-SW (right stepping faults) they may well constitute Riedel faults, which have impacted the sedimentary nappe and which are associated with a large-scale sinistral movement of the bedrock. The impact and the tectonic regime, which created the Petousi-Souli strike-slip fault, has left its imprint throughout the area, where many minor faults, trending E-W were observed, as well as other faults, which are affected by the same regime that caused the rupture of the main fault, albeit developing in a different direction. A number of surfaces were detected; the nature however of the geological materials at their contact did not enable the identification of kinematic evidence, since their surfaces and tectonic striations have largely disintegrated due to erosion. Results Due to its well-preserved fault surfaces and the limited erosion effect, this tectonic structure is indicated to apply the RC method. Specifically, by fieldwork, rock varnishes were found both in the Petousi-Souli segment, Agia Maura segment and in Saloniki ones. According to the methodology, calcium, titanium, and potassium cations were analyzed, and their concentration was determined in percentages at 21 sites. From these measurements using the Dorn’s equation (1; 1983), the RC ratio takes values between 2.1 and 110.1 corresponding to ages from 10.000 to 3.8 Ma years ago (Table 1). Table 1. Distribution of the RC ratio by fault and the varnish age based on the Nobbs and Dorn (1988). Fault RC Dating Petousi-Souli 2.4 - 110.1 10,000 - 2.2 Ma Agia Mavra 2.2 - 62.6 220,000 - 3 Ma Saloniki 2.1 - 13.3 10,000 - 3.8 Ma Discussion - Conclusions Tectonic and geological observations made in the field, geomorphological features (Ntokos, 2018a), paleomagnetic data (Kissel et al., 1985), paleoseismological data (Boccaletti et al., 1997), and recent microseismicity records (Pavlides, Caputo, Zouros, Mountrakis and Boccaletti (1992), Tselentis et al., 2006) all indicate recent fault activity. According to Boccaletti et al. (1997), over the last 30,000 years, at least three tectonic paleo-events are particularly associated with the Petousi-Souli Fault. Initial fault activation, based on recent tectonic geomorphological data on the evolution of northwestern Greece (Ntokos (2018a), dates to between the Miocene and Pliocene, which is similar to the rock varnish ages. In addition, it is worth mentioning that in the Petousi-Souli Fault the dating of the rock varnishes gave better results compared to other areas, e.g. Arkitsa (Ntokos, 2019) and Epirus, Greece (Ntokos, 2018), where the same method was applied to faults due to the well-preserved fault surface, verifying the application of the method to tectonic structures.

References Boccaletti, M., Caputo, R., Mountrakis, D., Pavlides, S., Zouros, N., 1997. Paleoseismicity of the Souli Fault, Epirus, Western Greece. Journal of Geodynamics, 24(1–4), 117–127. Dorn, R.I., 1983. Cation-ratio dating: A new rock varnish age determination technique. Quaternary Research, 20, 49-73. Kissel, C., Laj, C., Muller, C., 1985. Tertiary geodynamical evolution of northwestern Greece, Paleomagnetic results. Earth Planet. Sa. Lett, 72, 190-204. Nobbs, M.F., Dorn, R.I., 1988. Age determinations for rock varnish formation within petroglyphs: cation-ratio dating of 24 motifs from the Olary region, South Australia. Rock Art Res., 5, 108-146. Ntokos, D., 2018a. Formulation of the conceptual model for the tectonic geomorphological evolution of an area: five main rivers of Greece as a case study. CATENA, 167, 60-77. Tselentis, G., Sokos, E., Martakis, N., Serpetsidaki, A., 2006. Seismicity and seismotectonics in Epirus, western Greece: results from a microearthquake survey. Bull. Seismol. Soc. Am., 96, 1706-1717. [Journal Article] Ntokos. D., 2019. Dating the varnishes of active Kamena Vourla - Arkitsa fault zone (Northwestern Evoikos Gulf, Central Greece) using Portable XRF. 7th International Conference on Coupled Thermo-Hydro-Mechanical-Chemical (THMC) Processes, University of Utrecht, Utrecht, Netherlands, 03-05 July 2019 (In press). Ntokos, D., 2018b. Can cation-ratio dating of rock varnishes be applied in faults? 9th International Symposium on Eastern Mediterranean Geology, Akdeniz University, Antalya, Turkey, 07-11 May 2018, p. 221. [Conference Proceedings] Ntokos, D., 2017a. Neotectonic - Geomorphological study of Epirus, Northwestern Greece and compiling of neotectonic map, by use of Geographic Information Systems. Ph.D. Thesis, National Technical University of Athens, Athens, 404 p. (In Greek). [Dissertation]

ABSTRACT. Abstract: We present the main geological structure and architecture of the Hellenic orogenic belt, as well as the new aspects for its geotectonic evolution during the Alpine orogeny, based on our recent studies about the deformational history of the Hellenides but also on the more modern views, published from others colleagues, concerning the Alpine geotectonic reconstruction of the Hellenides. From the Jurassic to present day compression alternated progressively with extension leading to the structural making of the Hellenic orogen, while the Axios/Vardar suture zone should be traced in between the Rhodope nappe stack, and the Pangaion metamorphic core complex in the Rhodope province should be part of the Eastern margin of the Apulia plate (Pelagonia?).

ABSTRACT. The present study was conducted to determine the mineralogical and geochemical composition of the zeolitized volcaniclastic rocks in Petrota region of Evros prefecture. The mineralogical assemblage was studied under light polarizing microscope on 6 thin-polished sections and was further analyzed by X-ray powder diffraction (XRD) method. The thin-polished sections were also studied using Scanning Electron Microscopy (SEM). Chemical analysis was carried out on major and trace elements, on 12 representative samples using the X-ray fluorescence (XRF) method and 4 Acid digestion ICP-MS analysis, respectively.

ABSTRACT. Critical Raw Materials (CRMs) are those raw materials that are economically and strategically important for the European economy, but have a high-risk associated with their supply. It is important to note that these materials are not classified as ‘critical’ because these materials are considered scarce, rather they are classified as ‘critical’ because (http://criticalrawmaterials.org/critical-raw-materials) : (1) they have a significant economic importance for key sectors in the European economy, such as consumer electronics, environmental technologies, automotive, aerospace, defence, health and steel, (2) they have a high-supply risk due to the very-high import dependence and high level of concentration of set critical raw materials in particular countries and (3) there is a lack of (viable) substitutes, due to the very unique and reliable properties of these materials for existing, as well as future applications. Sb is classified as a Critical Raw Material (CRM) in all relevant official EU reports (e.g. European Commission, 2017). Applications of Sb include flame-retardants, alloys, pigments, semiconductors, pharmaceuticals etc. (e.g. Grund et al., 2006) and according to the latest EC report (2017), Sb has the third highest supply risk for the EU industry after the two categories of rare earth elements (LREEs and HREEs). Sb metal is recovered from ore primarily by pyrometallurgical techniques. Hydrometallurgical processing is suitable for some ores containing precious metals (Grund et al., 2006). According to Arvanitidis (2011) Sb ores in Greece are formed and found in veins at various areas of Rhodope, Thessaloniki and Chios Isl.. The concentration of Sb in these veins varies between 1 and 2.5wt.% and secondary mineral phases occurring with Sb minerals include Pb, Fe, Cu, Ag and Au sulphides. The indicative reserves of Sb from these areas are 2,400 tones and further research is required at these occurrences for the determination of their potential. According to Klocho (2019), worldwide reserves are 1,500,000 tones (rounded). Major Sb deposits are found China (reserves 480,000 tones), Russia (350,000 recoverable tones), Bolivia (reserves 310,000 tones), Australia (reserves 140,000 tones) and Turkey (reserves 100,000 tones) (Klocho, 2019). China is the main global supplier with a share of 87% of the world production (European Commission, 2017). The most promising Sb occurrence in Greece is found in the mixed sulphide ore deposits of Kassandra mining district (NE Chalkidiki). This is clearly depicted in the concentration of Sb in the concentrates produced from these mines: Sb is found having a concentration of 712.9 ppm in the Py-AsPy concentrate from Olympias, 748.2 ppm in the ZnS concentrate from Stratoni and >2000 ppm in the PbS concentrate from Stratoni (Tzamos et al., 2019). Although Sb is a CRM present in many localities from Greece, detailed studies regarding the mineralogy and geochemistry of Sb minerals and ores of Greece have not yet been made. Thus, the scope of the present study is to report new results concerning the mineralogy and the chemistry of these minerals from different Greek localities. For the present study, twelve (12) Sb-bearing ore samples from Lachanas (Thessaloniki), Chios Isl., Kassandra mining district (Olympias and Stratoni, Chalkidiki) were concerned. Polished sections were mounted from each sample and were examined in optical microscope (Fig. 1). After examination in optical microscope, scanning electron microscopy (SEM) images and microprobe analyses (EPMA) were obtained using a JEOL 8200 electron probe micro-analyzer equipped with a wavelength dispersive spectrometer (WDS). Analytical conditions were: 15kV accelerating voltage, 15 nA beam current, 2 μm beam diameter with a counting time of 20 s on the peaks and 10 s on the background. The approximate detection limit was 0.01 wt.% for each element.Also, four (4) representative samples were analyzed for their concentration in trace elements using Perkin Elmer ICP-OES/MS after standard fusion and acid-digestion. Microscopic study of polished sections under the optical microscope and SEM, revealed the presence of stibnite in Olympias (sample O1), stibnite (sample M1) and boulangerite along with galena, pyrite and sphalerite (sample M2) in Stratoni, boulangerite in Lachanas (sample K1), stibnite (sample C4) and valentinite (sample C5) in Chios. Microprobe analyses showed that all Sb-bearing minerals have typical concentration regarding their content in major elements. Table 1 presents the results of the chemical analyses for some trace elements analyzed. Elevated concentrations of samples of samples M1, M2 and O1 in Ag, Mn, Cd and Sn is attributed to the presence other mineral phases (e.g. galena) micro-inclusions and impurities, along with Sb minerals. Regarding other trace elements, sample M2 shows an unusual high concentration in Bi (1610 ppm), sample M1 has an elevated concentration of Se (10 ppm) and sample K1 contains significant amount of Hg (10.08 ppm). Moreover, Tl shows enrichment in three out of the four analyzed samples: 92 ppm in sample M2, 15.12 ppm in sample O1 and 8.80 ppm in sample K1. Elevated concentrations in Bi, Se, Hg, and –especially- Tl and their geochemical significance are part of our ongoing research concerning the Sb ores of Greece along with research on the development of methods for the extraction of Sb from mixed sulphide concentrates.

Figure 1. Stibnite (left-sample M1) and boulangerite (right-sample M2) from Stratoni, reflected light (N //).

Table 1. Trace element concentrations of the studied samples. Element Mo Ag Mn Cd Bi Sn Se Te Tl Hg Unit ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm Detectionlimit 0.05 20 1 0.02 0.04 0.1 0.3 0.05 0.05 0.01 Sample M1 (Stratoni) <0.05 26759 63 0.94 0.69 15.7 10.0 0.05 0.58 0.37 Sample M2 (Stratoni) 0.12 >200000 428 21.85 1609.67 69.7 0.8 2.74 92.00 0.22 Sample K1 (Lachanas) <0.05 1391 3 0.74 6.73 0.2 <0.3 <0.05 8.80 10.08 Sample O1 (Olympias) 0.29 70047 3074 8.17 4.20 83.7 0.7 0.17 15.12 n/a1 1: n/a = not analyzed

Conclusions • Sb (considered as a Critical Raw Material) is reported to have potential for exploitation from Greek ores, especially from the Kassandra mining district were new methods for its extraction from the sulphide concentrates must be developed • Sb-bearing minerals found in Greek relevant ores are antimonite, stibnite, boulangerite and valentinite with typical chemical composition in major elements. • Mineral samples hand-picked and analyzed with ICP-ES/MS were found to have elevated concentrations in various trace elements (Bi, Se, Hg and Tl) with ongoing research aiming to reveal the significance of this fact.

Acknowledgements This research is implemented through IKY scholarships programme and co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the action entitled ”Reinforcement of Postdoctoral Researchers”, in the framework of the Operational Programme ”Human Resources Development Program, Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) 2014 – 2020.

References Arvanitidis, N., 2011. Reserve potential of Greek non-energy minerals. http://nikolaosarvanitidis.eu/?p=234 (accessed on 21/03/2019-in Greek). European Commission, 2017. Study on the review of the list of Critical Raw Materials. Written by: Deloitte Sustainability, British Geological Survey, Bureau de Recherches Géologiques et Minières, Netherlands Organisation for Applied Scientific Research, 93p. Grund, S.C., Hanusch, K., Breuning, H.J., Wolf, H.U., 2006. Antimony and antimony compounds, in: Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim. http://criticalrawmaterials.org/critical-raw-materials (accessed on 21/03/2019) Klocho, K., 2019. Antimony. U.S. Geological Survey, Mineral Commodity Summaries, February 2019, 22-23. Tzamos, E., Papadopoulos, A., Grieco, G., Stoulos, S., Bussolesi, M., Daftsis, E., Vagli, E., Dimitriadis, D., Godelitsas, A., 2019. Investigation of trace and critical elements (including actinides) in flotation sulphide concentrates of Kassandra mines (Chalkidiki, Greece). Geosciences (under review).

ABSTRACT. In this study the mineralogical and geochemical characteristics of selected Ni-lateritic profiles and sedimentary Fe-Ni-deposits from the broader area of Lokris are discussed, towards a more comprehensive interpretation of the environment of deposition and the diagenetic evolution of the ores. Samples were taken from the Ni-laterite profile of Metochi area, as well as along four vertical profiles at the Nissi, Kopaida and Agios Ioannis (North Sector) and Villes Karstic-Nickel deposits, which represent allochthonous lateritic deposits, deposited over the karstified limestone. The comparative mineralogical and geochemical study of the different deposits demonstrates that the formation of Karstic Nickel ore-types took place in variable depositional environments with fluctuations in the hydrological regimes. Preliminary vitrinite reflectance data indicate a middle catagenesis maturation stage.

ABSTRACT. The subject addressed in the present contribution is related to the application of Near Infrared Spectroscopy on calcite-rich rocks for mineralogical identification. . The use of NIR spectroscopy is an easy and straightforward method that can determine the mineralogical composition of carbonate rocks. The aim of the present work is to compare the spectral signatures of Near Infrared region for different lithotypes, with a semi-quantitative mineralogical determination and their petrographic study. For this reason, limestones, marbles and calcitic sandstones were used to determine how the participation of other minerals influence the spectral features obtained.The samples analyzed were collected from Astypalaia in the Aegean Sea, Greece. For the petrographic analysis, thin sections were prepared and studied using polarized microscope in order to determine the mineralogical composition of each sample and their textural characteristics. Furthermore, through X-Ray Powder Diffraction analysis the mineralogy of the samples was verified, and a semi-quantification was performed. The Near Infrared spectra were acquired on the smooth and clean surface hand specimens with a SM-3500 Spectral Evolution portable spectrometer. Furthermore, the Cathodoluminescence method provided us more information about the mineralogy of the sample, that was not perceptible through normal observation, during the petrographic analysis.

ABSTRACT. The present work deals with the mineralogical and petrographic study of Greek magnesite and its host rocks at the area of Mantoudi of N. Euboea of Greece which belongs to the Pelagonian Zone. The magnesite deposits of N. Euboea which are hosted by Alpine type ultramafic rocks are the major magnesite producing areas of Greece. Greece is a EU country with a significant mineral resources background in terms of quality, quantity and variety of ores and minerals. The Greek Mining/Metallurgical Industry (GMMI) constitutes an important sector of the economic activity of the country as it supplies essential raw materials for primary industries and various downstream users. One of the abundance of ores is magnesite, which is used in several industrial applications as fertilizer, filler in rubber materials, in colour industries etc (Haben, 2002, Skliros, 2013). Nevertheless the main uses of magnesite are the production of caustic magnesia and other basic refractory materials. (Newman, 1997, Lampropoulou, 2003). The last 100 years the intensive exploitation of magnesite ore of this area led to the significant reduce of the resources and simultaneous increase of the total cost of the production. The Greek industry should be remaining to the forefront of the developments. In this direction the continuous research for new industrial applications of magnesite and its products is demanded. Moreover the host rocks of magnesite (waste after exploitation) could be a new direction to their utilization contributing to the circular economy. Nowadays, TERNA MAG is a magnesite and magnesia producer, member of GEK TERNA GROUP, one of the leading business groups in Greece. It exploits the world-class magnesite deposits in the northern part of Euboea island. In this work, samples of magnesite and its host rocks collected from Gerorema and Babakas mining areas in order to be studied. They have been analysed by petrographic microscopy, X-ray Diffractometry (XRD) and Scanning Electron Microscopy with EDS system (SEM-EDS). Gerorema is the main metalliferous area where magnesite is mined in underground mining and characterized from high-purity, boron-free and low-iron, calcium and silicon impurities. (Gartzos, 1985). The results of the petrographic features, textures characteristics and mineralogical compositions are presented here. According to the results magnesite of Gerorema area, characterized as microcrystalline to cryptocrystalline while sometimes veins of crystalline magnesite have been detected in peridotites (Figure 1). The host rocks of this area are ultramafic rocks of dunite, harzburgite, lherzolite as well as serpentinite. Through the polarizing microscope and the respective XRD pattern the pure cryptocrystalline magnesite rock (consisted of about 90% magnesite) is indicated in Figure 2. In case of Babakas area the results indicated that pure cryptocrystalline magnesite is hosted in ultramafic rocks, especially of serpentinized harzburgite. (Figure 3). This work introduced the idea of the synergy of these rocks, (without extensive enrichment) in several tested mixtures as raw materials for the production of new alternative low cost ceramics or aggregates, contributing further to the industrial development, save energy and economy.

ABSTRACT. Two zones of zeolitic tuffs are located approximately 2 km westwards and northwestwards of Petrota village at Evros region, northeastern Greece. During the recent decades several detailed publications have been published on the mineralogy, geochemistry, quality characteristics and applications of these zeolitic tuffs. The present study is an attempt to review and also add new data on the geological aspects of the zeolitic tuffs regarding their mineralogical and structural features.

ABSTRACT. The Edessa ophiolite represents remnants of an oceanic lithosphere obducted onto Palaeozoic-Mesozoic marble and schists during Upper Jurassic to Lower Cretaceous (Decourt et al., 1977, Michailidis, 1990). The ophiolitic rocks include several tectonic units that are considered to be the northwards continuation of the Veria-Naousa ophiolite (Pe-Piper and Piper, 2002, Saccani et al., 2008, Rogkala et al., 2017). Petrographic, geological and geochemical evidence indicates that this ophiolite complex consists of both mantle and crustal suites (Rogkala et al., 2019). It includes serpentinised harzburgite with high degree of serpentinisation, lherzolite, diorite, gabbro, diabase and basalt. This study presents new data on petrographic characteristics and geochemical compositions of mantle peridotites from this ophiolite, especially serpentinised harzburgite and minor lherzolite. The serpentinised harzburgite displays dark green colour and local relic pyroxenes with moderate to intense mantle deformation features, such as banding and foliation. Locally, it encloses lenses, pods or elongated bodies (up to few meters) of chromitite, which according to their texture and mode of occurrence, are classified as massive and disseminated podiform bodies. Moderately lherzolite is an infrequent, medium-grained rock, which is characterised by greenish black to dark green colour and conchoidal fracture. It occurs as relic, irregular bodies up to a few meters, surrounded by harzburgite. Local lherzolite slivers are repeated in the mantle domain of Edessa due to a series of imbricated thrusts occurring through the area. The petrographic description of the serpentinised harzburgite and lherzolite has been conducted in polished-thin sections from 35 samples, which have been collected throughout the whole exposure. The serpentinised harzburgite has been intensively serpentinised. The primary mineralogy constitutes less than 5% of the mode and comprises clinopyroxene, Cr-spinel and chromite (Figure 1a). Clinopyroxene appears as subhedral porphyroclasts. The Cr-spinel crystals and chromite are subhedral to euhedral and scanning electron microscopic observation revealed that infrequently they show an irregular distribution of ferritchromite and Cr-bearing magnetite compositional areas, at their rims. Serpentine is the main alteration product showing mesh, ribbon, bastite and intersertal textures. Chlorite and magnetite are also products of hydrothermal alteration of the serpentinised harzburgite. Lherzolite displays mainly porphyroclastic texture (Figure 1b). Its primary mineralogy includes olivine (40-60 vol%), orthopyroxene (30-40 vol%), clinopyroxene (5-25 vol%) and spinel (up to 5 vol%). Rare Fe-Ni-Co sulphides with Cu coexist with spinel. Olivine displays porphyroclastic grains and smaller neoblasts. Orthopyroxene porphyroclasts exhibit local kink-bands, undulatory extinction and exsolution lamellae of clinopyroxene. Olivine and orthopyroxene porphyroclasts surrounded and partly replaced by neoblastic olivine (Figure 1b). Clinopyroxene occurs as porphyroclastic and neoblastic grains in the recrystallised matrix (Figure 1b). Spinel is of aluminous composition and forms subhedral to euhedral grains with lobate boundaries, which veined and surrounded by a rim of garnet and sulphides. Various serpentine, chlorite, tremolite and magnetite are observed due to subsequent hydrothermal alteration. Major, trace and rare earth elements data from the mantle peridotites from the Edessa ophiolite were performed at Bureau Veritas Mineral Laboratories at Vancouver (Canada). Major element analyses were carried out using an XRF spectrometer and a sequential spectrometer (ICP-ES). Trace elements and rare earth elements were determined on totally digested samples by inductively coupled plasma-mass spectrometry (ICP-MS) in the same laboratory. Detection limits for major and trace elements range from 0.01 wt.% to 0.04 wt.% and from 0.01 ppm to 10 ppm, respectively. The analytical precision calculated from replicate analyses is better than 3% for most major elements and better than 5% for trace elements. Lherzolite is richer in SiO2, TiO2, Al2O3 and CaO than the serpnetinised harzburgite. Low CaO and Al2O3 contents in serpentinised harzburgite are consistent with low clinopyroxene abundance. The serpentinised harzburgite shows higher Mg# [100*Mg2+/(Mg2++Fe2+)] ranging from 82.27 to 84.79 than the lherzolite (82.33-83.74). Trace element abundances are also highly variable among the mantle peridotites. More specifically, lherzolite is richer mainly in V, Sc, Ga and Y compared to the harzburgite. On the other hand, the serpentinised harzburgite exhibits higher Co, Zn, Ni and Cr abundances than the lherzolite. The total rare earth element (REE) inventory of the Edessa peridotites is variable, ranging between 0.20 to 4.74 ppm. They exhibit a more limited range of heavy REE (HREE = Er + Tm + Yb + Lu = 0.00-1.04 ppm) abundances compared to that of light REE (LREE = La + Ce + Pr + Nd = 0.20-2.50 ppm) and middle REE (MREE = Sm + Eu + Gd + Tb + Dy + Ho = 0.00-1.88 ppm). Lherzolite displays higher REE concentrations with respect to serpentinised harzburgite. Lherzolite is characterised by relatively LREE-depleted primitive mantle-normalised REE patterns, exhibiting a nearly linear increase from LREE to HREE (Figure 2). Most of them bear resemblance to abyssal peridotites in terms of primitive mantle-normalised REE profiles (Niu, 1997), especially in MREE and HREE segment. The serpentinined harzburgite shows higher depletion in MREE and HREE compared to abyssal peridotites, whereas their REE patterns reaching up to and below to the field of SSZ-type peridotites (Figure 2). Lherzolite formed by low to moderate degrees of partial melting and subsequent melt-rock reaction in an oceanic spreading setting. On the other hand, refractory harzburgite formed by high degrees of partial melting in a supra-subduction zone (SSZ) setting. Petrographical characteristics and geochemical compositions of the mantle peridotites suggest that the Edessa oceanic mantle evolved from a typical mid-ocean ridge (MOR) oceanic basin to the mantle wedge of a SSZ. This scenario explains the higher degrees of partial melting recorded in harzburgite, as well as the overprint of primary geochemical characteristics in the Edessa peridotites.

ABSTRACT. The aim of this study is to investigate and determine the colour changes in experimental ceramic briquettes through different states (from unfired to be fired at 1050oC) using Visible Near Infrared Reflectance Spectroscopy (VNIR). Initially the studied material was examined in terms of colour following the ordinary method of Munsell Chart. Reflectance spectroscopy has been defined as a technique that uses the excitation energy in the Visible-Near Infrared wavelength regions of the electromagnetic spectrum to identify minerals. The Visible Near Infrared spectroscopy (VNIR) contributed to a more accurate determination of colour, since we can obtain tristimulus values from visible region. The main factors which are responsible for the colour changes is the presence of different minerals as well as the conditions during firing. The mineralogical determination was performed by X-ray Powder Diffraction (XRPD) in order to identify and confirm all the primary minerals and the neoformed mineralogical phases as a result of the firing regime. The experimental briquettes were prepared using clayey raw materials which were collected from Achaea and Corinth (Northern Peloponnese, Greece) and were fired at three different temperatures (700, 900 and 1050oC) under oxidizing conditions.The examined samples were characterized calcareous, calcareous-dolomitic and siliceous clayey raw material, based on XRPD results. VNIR spectrometer results were obtained into tristimulus values X, Y, Z and converted into Munsell colour notations. VNIR spectra results offers a quantitative measurement of colour in relation to the Munsell soil chart through which colour is determined qualitatively. The use of the NIR spectrometer may provide an alternative untrained approach that can produce results not only for colour coordinates but also about the reflectance spectra, which contain more information about mineral identification.

ABSTRACT. The intrusion of the Sithonia Plutonic Complex has caused contact metamorphic phenomena to the metasediments of the Circum-Rhodope Belt. Assemblages including calcsilicate minerals, such as vesuvianite and grossular, are observed in the contact aureole metamorphosed rocks. Based on the study of these assemblages, the formation conditions were estimated at the temperature of 500-600oC, whereas the pressure did not exceed the value of 6 kbar. The metamorphic reactions took place in the presence of H2O-rich fluids.

ABSTRACT. Introduction and Geological Background Limestones are extremely valuable raw materials with a wide variety of chemical and industrial uses which are determined by their physical and chemical properties. The latter, in turn, directly depend on their depositional processes and environments but, also on the post-depositional (diagenetic) alterations that they have undergone. So, the geological, mineralogical and petrographic observations of the limestones are necessary to predict the chemical properties of the end products which can be produced from them (Freas et al., 2006). Accordingly, Eocene Limestones from Zakynthos Island were examined in order to establish certain qualitative characteristics which could contribute to their assessment for various industrial uses. The studied limestones are part of the carbonate succession of the Paxos (or Pre-Apulian) tectonic unit that crops out on the Ionian Islands, in western Greece, and represents the foreland of the Hellenides. After the Early-Middle Jurassic rifting, the Paxos unit functioned as an isolated carbonate platform which received exclusively and almost uninterruptedly calcareous sediments until the Oligocene, when it was completely foundered. The older rocks of the Paxos unit exposed on Zakynthos are of Upper Cretaceous age, constituting the Vrachionas mountain range, a calcareous anticline with a NNW-SSE treding axis. The Eocene Limestones, as well as all the younger formations, occur mostly on the eastern sides of the Vrachionas, constituting an east-dipping monocline (Fig.1A). Material and Methods Fieldwork included detailed facies analysis in three old quarries in central Zakynthos (Fig. 1A) and sampling of more than 50 selected samples. Polished slabs and thin sections were prepared of all the samples that were also stained with Alizarin red S and Potassium ferricyanide. The depositional and diagenetic characteristics were examined using transmitted light microscopy while the mineralogical composition of the non-carbonate material was determined through X-ray diffraction (XRD) analysis of the insoluble residue of the <30μm and <2μm fractions of selected samples, subsequent to their treatment with Η2Ο2 to remove any organic matter. Chemical analysis of selected samples was performed using X-ray fluorescence spectrometry (XRF) technique. Results Two main lithofacies were identified: a) thinly to medium bedded calcilutites with alternating whitish and light-brown beds and some scattered chert nodules and b) massive to very thickly bedded white to very pale grey calcirudites (Fig 1B). The calcilutites comprise pelagic-hemipelagic carbonate deposits and are mainly represented by pelagic foraminiferal mudstones to wackestones (Fig. 2a), often with burrows, and fine-grained bioclastic packstones with abundant transported neritic skeletal fragments. Mineralogical study revealed that they consist mainly of non-ferroan low-magnesian calcite while their insoluble residue consists mostly of a-quartz (microquartz) and less clay minerals (smectite, illite, kaolinite and vermiculite) (Table 1). Chemical analysis showed CaO content of 54.75% (corresponding to limestone with 97.71% CaCO3), MgO 0.63%, SiO2 0.14% while the percentacges of all other oxides are in the range of <0.10% to negligible (Table 2). The calcirudites constitute very coarse-grained, polygenetic limestone breccias, with a grain-supported fabric, very poor sorting and without internal sedimentary structures. They consist of numerous reefal blocks (Fig. 2b) and bioclastic lithoclasts (Fig. 2c), originating from the platform-margin and shelf, and minor pelagic intraclasts of similar composition to their minimal matrix (pelagic wackestone). Facies analysis and petrographic study clearly showed that they constitute resedimenented limestones deposited mainly by debris flows at the base of a carbonate slope environment (Kati, 2006). Despite their clastic nature, they show great mineralogical homogeneity, the dominant mineral being the above low-Mg calcite. Their insoluble residue, although qualitatively and quantitatively is almost the same with that of the calcilutites, comprises mainly clay minerals and less a-quartz (Table 1). Their chemical composition showed CaO rates from 55.15-55.75% (corresponding to limestone with CaCO3 from 98.5-99.1%), while of the other oxides only MgO is most abundant (0.51-0.68%) and the percentages of the remaining are < 0.05%. Ιt should be noted that the organic content was essentially negligible in both lithofacies and dolomitization phenomena are entirely lacking. Conclusions Based on their carbonate content, the two lithofacies constitute ultra-high-calcium limestones (more than 97% CaCΟ3) (Oates, 1998) which are considered suitable for many high-value chemical and industrial uses. The two lithofacies, however, are diversified as to type, size and origin of their constituent grains, as well as their depositional mechanisms and diagenetic paths, resulting in differentiation of their chemical purity. Specifically, although calcilutites display the greatest homogeneity in their primary constituents, their qualitative characteristics appear to have been affected by the presence of detrital clays that arrived in their depositional setting, and also from extensive phenomena of silicification during diagenesis. Their carbonate content (<98.5% CaCO3) classifies them as “high purity limestones” (Cox et al., 1977) that can be used in cement manufacture, fertilizer industry, in metallurgy, for flue-gas desulphurization, in various environmental uses, etc. The calcirudites (limestone breccias), despite the considerable heterogeneity in their components show better quality characteristics in relation to calcilutites. The origin of most of their clasts and their early lithification are directly reflected in their mineralogical and chemical composition. Their impurities probably represent only clay minerals of detrital origin, since other main diagenetic alterations were not observed. Therefore, the studied breccias with CaCO3 content >98.5% (“very high purity limestones”) can be used in applications even of higher value, as in production of lime, fillers and pigments in paper, paint and plastics industries and pharmaceutical uses.

ABSTRACT. Carbon dioxide sequestration (CCS) is considered to be the future for the reduction of the industrial carbon emissions (Baena-Moreno et al., 2019). Nesquehonite synthesis has been proposed as a promising permanent storage of CO2 emission under low pressure conditions, with competitive properties as building material. In this work, we study the cementitious characteristics of nesquehonite synthesized in high alkaline environment and under low-pressure conditions by reaction of gaseous CO2 with Mg-chloride solution, as following: MgCl2·3H2O + CO2(g) + H2O  MgCO3·3H2O(s) + 2H+ A saturated Mg2+ solution was used for its synthesis, at a temperature of 25℃ and pH 9.3. During the reaction, since the pH tended to reduce, a continuous input of NH3 solution of high concentration (35%) was required to keep the pH in alkaline values (Ferrini et al., 2009). The NH3 solution didn’t react with the products and was easily separated by using a vacuum pump. Nesquehonite synthesized herein was subsequently studied by means of X-Ray Diffraction, optical microscopy (Figure 1), scanning electron microscopy (Figure 2), FT-IR and Raman spectroscopic methods. Synthesized nesquehonite forms elongated fibers, exhibiting transparent to translucent diaphaneity and vitreous luster. FT-IR and Raman spectroscopy revealed the presence of OH- and CO3- in the crystal structure of nesquehonite. After being synthesized, nesquehonite was examined for its cementitious characteristics, by mixing it with reactive magnesia, standard aggregate sand and water to create a mortar. The new mortar was cast into 5x5x5 silicone mold and cured in water for 28 days (Figure 3a). The sample achieved a compressive strength of 14 Mpa after 28 days (Figure 3b). Subsequently, it was studied by means of X-Ray Diffraction and FT-IR spectroscopy. XRD results indicated the presence of Mg(OH), which was formed after reactive magnesia hydration. FTIR study revealed the stability of CO3- in the binder of the mortar. As shown, a permanent storage of CO2 might be achieved by CO2 mineralization into a new nesquehonite-based "green" mortar with competitive properties. This method might be a part of Carbon Capture, Utilization, and Storage (CCUS) technologies to remove CO2 from the flue gas and from the atmosphere by providing a safe, permanent and useful storage option.

ABSTRACT. The area of Penteli represents the northwestern extension of the Attic-Cycladic Crystalline Belt. In this study, we focus on metapelitic lithologies (three rocks) and provide new geothermobarometric data (pseudosections) that constrain peak and post-peak P-T evolution of the LTU of Penteli area in western ACCB. Data gathered from mineral compositions and assemblages, textural relationships, Perplex_X calculations (P-T pseudosections, isopleths) demonstrate that these rocks underwent HP/LT metamorphism. The studied LTU rocks underwent similar high-P/low-T conditions of formation, in which a distinct post-peak history characterized by heating along a clockwise P-T path is suggested. These rocks recrystallized within a subduction channel environment. The post-peak T history is almost identical with the path proposed for the Syros rocks which characterized by heating during exhumation continuously from P~12 kbar, and then by cooling from P~8 kbar and onward. Finally, the present position may suggest either a mechanism which incorporates lateral extension of ~ 100 km or the two areas where part of the same heterogeneous (Syros reached much deeper parts; ~35–40 difference for their maximum depth recorded in the two units) subduction/exhumation system but at different places in the horizontal scale.

ABSTRACT. The Kallianos deposit is located in south Evia at the northern part of the Attico-Cycladic Metallogenetic Massif and consists of carbonate-replacement and vein-type ores. The Au-Ag-Te vein mineralization associates with sixteen ore-bearing syntaxial quartz-I and -II type veins that intersect the schists and marbles of the Cycladic Blueschist Unit. The veins comprise two hypogene ore stages which involve the deposition of stage I-pyrite, and stage II-chalcopyrite, galena and tellurides. Zones of muscovite-chlorite alteration surround the quartz-I and -II type veins. Bulk chemical analyses of the quartz-I and quartz-II veins and related sulfides from Kallianos suggest that they are enriched in Au, Ag and Mo. They also display Th/U values ≤ 7.8, (La/Sm)N ratios of ~ 0.2 to 0.7 and moderate negative Ce/Ce* and Eu/Eu* anomalies. Raman and chromatographic analyses suggests ore-fluid gaseous phase contains mostly CO2, N2, and H2S, minor H3BO3, O2, H2, CH4, and H2Te and traces of He and Ar (Fig 1a, b). Bulk composition of the ore fluid liquid phase indicates that Cl- is the dominant anion in the ore solution and Si+4, Mg+2, Ba+2, Pb+2, Fe+2(total) and Zn+2 the dominant cations (Fig. 1c). Stage I-ore fluid bears log(Ca+2/Ba+2) values in respect to the stage II-ore fluid which is characterized by higher log(Fetotal/Mg+2) values (Fig. 1d). He, Ar and Ne isotope compositions were also obtained from fluids extracted from the same samples. Their 3He/4He, 40Ar/36Ar, 20Ne/22Ne and 21Ne/22Ne compositions range from 0.02-0.08 RA, 1139-1809, 8.94-9.71 and 0.05-0.15, respectively (Figs. 2a, b). A magmatic origin is deduced for the ore fluids in equilibrium with quartz-I and -II based on measured noble gas isotopic compositions. The Upper Continental Crust-normalized REE profiles of the Kallianos quartz veins and vein-type ores appear mildly enriched in the LREE relative to HREE. The Kallianos REE patterns, share many common features to the granodiorite of Plaka and related aplites, carbonate-replacement and vein-type ore deposits (Berger et al., 2013). Moreover, these REE patterns have some similarities with the Tinos leucogranite, aplites and smoky quartz from Volax and quartz veins from Panormos Bay (Tombros et al., 2007, 2010). However, Tinos REE patterns appear with some differences in their LREE patterns relatively to Kallianos. On the N2-He-Ar plot (Fig. 1b) the gaseous phase of both stage I and II ore fluids plots in the magmatic waters field. The linear trend observed on the same plot (i.e., on the N2-Ar join, Fig. 1b) indicates simple cooling of the ore fluids. The Kallianos ore fluids, based on noble gases isotopic compositions resemble to both Lavrion and Tinos ore fluids, even Tinos has lower 20Ne/22Ne isotopic values (Fig. 2a, b). Fluid chemistry of the liquid phase suggests that the Kallianos ore fluids mainly plot close to the ore fluids exsolved from the Plaka granodiorite (Lavrion), and more infrequently close to Tinos (Fig. 1b and d). Moreover, in the log(Ca+2/Ba+2) versus log(Fetotal/Mg+2) plot the quartz-II ore fluid lies on the mixing line defined between Tinos and Lavrion end-members (Fig. 1d). An important issue addressed in our study is that a possible magmatic source is indicated from the bulk geochemistry of the quartz-I and-II veins, fluid chemistry and noble gas isotopic compositions (Figs. 1, 2). In order to estimate the possible distance from where the ore fluid could have been exsolved and then transported, we have applied a convective heat-transfer flow model. This model considers as sources the Lavrion and Tinos granitoids, which are the closest to the Kallianos ores (e.g., currently at ~60 and 85 km). It is also based on steady-state fluid flow and simple cooling of the ore fluids, using as a pathway the CBU secondary detachment between the schists and marbles. In the fault damage zone the driving flow mechanism was horizontal fluid convection that resulted in the fluctuations of temperature of the ore-fluid over distance and time. For the simplest case (fluid velocity ≈ 9.10-3 km/Ma, by analogy to Panormos Bay, Tinos, Tombros, 2011), the equation is: (1). Modelling parameters are T(x) = 230oC, t = 2 Ma for Plaka’s granodiorite, Lavrion and 4 Ma for Volax, Tinos, and x0 = 0, i.e., the Plaka and Volax sites. At t0 = 9.4 Ma, the ore fluid from Lavrion (T0 = 460oC, P ≤ 200 bars, salinity of ~ 55 wt. % equivalent NaCl, Bonsall et al., 2011) or at t0 = 10 Ma, the fluid from Tinos (T0 = 320oC, P ≤ 200 bars, salinity of ~ 5 wt. % equivalent NaCl, Tombros et al., 2007) commenced to flow in the fault zone. Pressures obtained from fluid inclusions for Kallianos are P ~ 125 bars, nevertheless, the temperatures are lower due to the greater distance from the granitoid source and simple cooling of the ore fluids. Solving equation (1) for distance, we conclude that if the fluid moved in the marbles-schist interface it would have flown for a distance of 22.4 to 27.6 km away from Plaka, Lavrion or 23.9 to 29.4 km away from Volax, Tinos. Based on our geochemical results and numerical simulation of temperature over distance we examine two possible scenarios about the source of the Kallianos ore fluids. The first involves the granodiorite of Plaka in Lavrion area. Bradley et al. (2013) reported that Attica and Evia have experienced ~ 25º ± 6.5º of post-Middle Pliocene clockwise rotation which is linked to acceleration of the Aegean subduction slab retreat and the subsequent initiation of the Evia and Corinth Gulf rifting. In a pre-rotational setting at ~ 9 to 8 Ma the areas of Kallianos, Plaka-Sounio in Attica could have been at a distance of ≤ 20 to 25 km, i.e., the calculated distance that the ore fluid had travelled along the CBU detachment or the WCDS. The second scenario implicates the Tinos leucogranite as a source of the ore fluids exsolved from Volax site. In a similar case at Panormos Bay, Tinos (Tombros et al., 2007, 2010), the Au-Ag-Te mineralization was linked to the volatile evolution of the Tinos pluton, which at surface is ~ 16 km from the leucogranite. Channelized flow at depth may have occurred along the damage zone of the detachment interface between the BU marbles and the CBU or alternatively along the contact between the CBU and the UCU. However, for the Au-Ag-Te bearing ore fluid originated from Tinos the calculated distance that the ore fluid may had moved along the CBU detachment or the NCDS was ~ 24 to 30 km. It seems that Tinos leucogranite could only have promoted mineralization up to Panormos Bay, as recommended by Tombros et al. (2007, 2010). Herein, we propose that Kallianos is an outlier or satellite ore deposit of the Lavrion hydrothermal system with Plaka’s granodiorite as the major source for the Au-Ag-Te ore fluids. A possible subsurface pluton with similar characteristics cannot be excluded but there are not any data for its presence so far.

ABSTRACT. Clays and clay minerals are widely used in environmental applications due to their ability for adsorption and removal of heavy metal contaminants, organic and biological cations and non-ionic organic compounds. In this study the environmental risks associated with the waste disposal facility in the municipality of Zakythos and the extent of the leachate adverse impacts on the natural soil environment was evaluated. The mineralogical composition of the samples collected from the landfill site revealed the presence of abundant clay minerals which are widely used as natural clay barriers in waste disposal sites. The mean chemical composition of the soil extractions and surface runoff waters show that stream sediments are becoming enriched in most of the analyzed physicochemical parameters. The concentrations of the aforementioned physicochemical parameters in the soil samples exceeded the average permissible concentrations and are considered as human induced contamination from the landfill.

ABSTRACT. The present research was conducted on the Pikrolimni Lake sediments (PLS). Pikrolimni Lake is located in the Kilkis district, near Thessaloniki (23 km), in northern Greece. It is a small shallow lake up to 1.5 m depth, and it is well known as a pelotherapy center. PLS are used for the preparation of peloid mud, but no detailed data exist on their characteristics. The aim of this investigation was to assess the texture, mineralogy and geochemistry of PLS. Chemical results were compared with reported Earth’s upper crust average shale (Li, 2000) as well as with different muds used for medical purposes. The index of geo-accumulation (Igeo) and the iron normalized enrichment factor (EF) were used for the characterization of PTE contamination levels. The results of this investigation aim at helping to develop suitable processes for making the PLS suitable for therapeutic uses.

ABSTRACT. The Mt. Papikion pluton stretches East-West from Iasmos to Komotini, and South-North from the Xanthi-Komotini fault to the Greek-Bulgarian border. The pluton, with characteristic gneissic texture, intrudes the SW parts of Kesebir-Kardamos Dome, and it is in contact with gneisses to NE and marbles to SW, representing the lower and the intermediate unit of Kesebir-Kardamos Dome, respectively. In this paper we focus on the genesis and the geotectonic setting of the Mt. Papikion pluton. Mt. Papikion pluton consists mainly of five rock types which have been classified on the basis of field observations, mineralogical composition and Q’-ANOR classification. These types are hornblende diorite (Hbl-Dr), biotite hornblende diorite (Bt-Hbl-Dr), hornblende granodiorite (Hbl-Grd), biotite hornblende granodiorite (Bt-Hbl-Grd) and biotite granodiorite (Bt-Grd). Based on field observations, isotopes and trace elements behavior, evolution of the plutonic rocks can be attributed to an assimilation with simultaneous fractional crystallization process (AFC). The rock types of the Mt Papikion pluton are essentially the result of the fractional crystallization process of two dioritic melts having small geochemical differences, which assimilate the rocks into which they intrude, namely gneiss and meta-SnGr (meta-syenogranite). U-Pb method in zircons gave an age of 236±8 Ma which considered as the age of crystallization as well as the age of the pluton intrusion, suggesting a magmatic episode in the Upper-Middle Triassic. The presence of basic rocks in Mt. Papikion pluton, suggests that a mantle component had a significant role in the genesis and evolution of the pluton. This feature in combination with petrotectonic and spider diagrams, suggest a volcanic arc magmatism. The lower unit of the Kardamos Dome consists of high metamorphic grade rocks, orthogneiss and migmatites, which also suggests its continental origin. The pluton of Mt Papikion intrudes mainly the orthogneiss, which indicates an environment of an active continental margin, in accordance to the geochemical data. The pluton’s emplacement occurs in the Middle Triassic. Geochemical characteristics show that the intrusion took place in an active continental margin. During the Middle Triassic, as various researchers state, the ocean of Paleo-Tethys closed and the ocean plate subducted under individual parts of Eurasian continental blocks (active continental margins).

ABSTRACT. Kaolin samples from the Oza-Nogogo area of Nigeria were studied for the first time, to assess the suitability of the material for use as raw material for the ceramic industry. Twenty samples were collected from four outcrops in Iduneha, Ewan, Uvbe and Ewebi, belonging to Ogwashi-Asaba Formation. The kaolinite content is very high, while quartz was the main impurity that was detected in variable quantities. Other secondary minerals, in only a small number of samples and in trace amounts, are dolomite, anatase, illite and iron oxides. In order to evaluate its industrial potentials, several diagnostic tests were performed, including particle size distribution, brightness and whiteness, specific surface area (SSA) and plasticity Index via Atterberg limit tests. Taking into account the high content of kaolinite, the grain size being <2 μm, the high values of brightness and whiteness and the very light brown color, the kaolin of these areas meets the industrial set requirements for the manufacture of low-quality ceramics. Specifically, due to its thick superficial strata, Iduneha is considered to have a significant economic interest. On the contrary, the occurrence in Ewan is of inferior quality, and its exploitation could be an option only after beneficiation. However, for high-quality ceramic products, the kaolin samples fail to meet the industry's high standards.

ABSTRACT. Τhe volcanic center of Lichades is located in the Northern Euboean Gulf and consists of a complex of volcanic islands and lava outcrops named Agios Ioannis and Vromolimni at the Kamena Vourla area, in mainland (Georgalas, 1938). Different theories have been proposed about Lichades volcanic center geological setting. Innocenti et al. (2010) based on Sr–Nd–Pb isotopic data, related this volcanic center with the large volcanic belt that developed north of the Pelagonian–Attic–Cycladic–Menderes massifs, encompassing a 35 Ma timespan which is widespread over a large area from NW Greece–Macedonia to the Aegean–western Anatolia. According to the above authors, the Euboea-Kamena Vourla volcanic products are orogenic in character and partially contemporaneous with the south Aegean active volcanic arc, but with different geochemical features, related to distinct magma sources. The volcanic center of Lichades are located along the major tectonic structures in the area (Kranis, 1999). Karastathis et al. (2011) showed that there is a magma chamber under the North Euboean Gulf area using low seismic P-wave velocity values and high Poisson ratios at depths below 8 km, also coincident with a Curie surface estimated at 7-8 km depth. Kanellopoulos et al. (2017a, 2017b) suggested that the volcanic center of Lichades and the associated magmatic chamber is the heating source and contributes with a portion of deep magmatic fluid to the geothermal fluid of Euboea-Sperchios system, alongside with seawater and only limited meteoric water contribution. Detailed petrographic analysis of volcanic rock samples collected from Agios Ioannis was conducted in thin sections, using polarized optical microscope (OM). Mineral composition has been determined by Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) and powder X-ray powder diffraction (XRPD). The volcanic rocks are characterized by vitrophyric texture. Their matrix is dominated by glass, numerous, randomly oriented microlites of plagioclase and minor sanidine, clinopyroxene and amphibole (Fig, 2a, b). Phenocrysts are commonly plagioclase, olivine, quartz, clinopyroxene and amphibole. Plagioclase occur as large euhedral to subhedral grains, displaying patchy or concentric zonation. At places, plagioclase phenocrysts are rimmed by a thin rind of K-rich feldspar (sanidine, Fig. 2c), which can rarely be found as phenocryst as well. Olivine is usually found as large, euhedral to subhedral grains or they can form glomerophyric aggregates along with clinopyroxene crystals. Sometimes, zoning and the existence of embayments in the crystals may indicate reactions with the host melt, as the crystallization was evolving through time. Amphiboles, mostly hornblende, is usually forming euhedral grains with characteristic zoning. Locally, replacement by opaque phases suggest minor opacitization processes. Resorbed quartz phenocrysts are uncommon, but they are always rimmed by clinopyroxene crystals. Vesicles are abundant and, in some cases, amygdules filled with euhedral clinopyroxene may occur. Clinopyroxene is also present as euhedral phenocrysts or even as glomerophyric aggregates. Sphene may occur as a rare accessory mineral. Finally, opaque phases, commonly spinel, magnetite and rutile are quite abundant, scattered in the vitreous matrix. A study of the bulk geochemical composition of selected samples was conducted by X-ray Fluorescence (XRF) and Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS). Major elements in the studied samples show a limited range of variation such as SiO2 (57.3-58.8 wt%), TiO2 (0.7 wt%) and Al2O3 (17– 17.5 wt%), MgO (3.1–3.4 wt%) and CaO (5.8–6.1 wt%). The volcanic rocks from Agios Ioannis plot in the fields of trachyandesites on the total alkali-silica (TAS) diagram. In the K2O vs SiO2 classification diagram, the studied samples plot in the field of high-K calc-alkaline series. Their trace-element patterns show relatively high Th and Ta contents, pronounced negative P anomaly and significant negative Rb, K, Ti and Y anomalies. The petrographic characterization and the geochemical signature of the Aghios Ioannis volcanics let us draw some preliminary conclusions of their petrological affinities, helping us to make some first inferences about their geotectonic evolution and their emplacement regime. The studied features are similar to geochemical characteristics of subduction-related rocks, with high normalized abundances of LIL elements and troughs in the normalized trace element plots at Nb, Sr, P and Ti. The small size of the volcanic centres of the studied area and the strong enrichment in incompatible elements suggest that the magmas resulted from small degrees of partial melting of an enriched subcontinental lithospheric mantle.

ABSTRACT. Introduction Earthquakes and volcanic eruptions represent a hazard. However, the impact of gases released in geodynamically active areas should not be underestimated. It is commonly known that geogenic sources release great amounts of gases, which, apart from having an important influence on the global climate, can also have a strong impact on human health causing both acute and chronic effects. In particular, CO2 and sulphur gases (mainly H2S and SO2) are the main compounds responsible for acute mortality due to their asphyxiating and/or toxic properties. One of the most known and also worst episodes occurred, took place on the 21th of August 1986 at Lake Nyos, Cameroon, when about 1700 people were killed and 850 injured by a massive CO2 release (D’Alessandro, 2006). Like other geodynamically active areas, Greece is also affected by a large number of geogenic gas manifestations (Daskalopoulou et al., 2018a). These occur either in the form of point sources (fumaroles, mofettes, bubbling gases) or of diffuse soil gas emanations (Daskalopoulou et al., 2018b). D’Alessandro and Kyriakopoulos (2013) made a preliminary estimation of the risk related to geogenic gases in Greece for the time period of 1992-2011; the whole population of the country was considered. In that period, at least two fatal episodes with a total of three victims took place, likely caused to the exposure to geogenic gases (specifically CO2). This would give a risk of 1.3×10-8 fatality from geogenic gas manifestations per annum. This value, although probably underestimated, is much lower than many other natural or anthropogenic risks. Since deaths due to natural gases are often wrongly attributed, it cannot be excluded that some fatal episode has not been recognized and thus that the risk is somewhat higher than assessed. Although very low, this risk should not be neglected, not only because it is possibly underestimated, but also because simple countermeasures could be adopted for risk reduction. Dangerous areas could be easily identified and delimited by geochemical prospecting and their hazards properly highlighted. Apart from the sites where fatal episodes occurred, many other hazardous sites have been recognized in Greece. Here we present data collected at Loutra Ypatis (central Greece). Study area Sperchios Basin – Evoikos Gulf Graben is a 130 km long actively spreading graben in Central Greece (1 cm/a). The high geothermal gradient of the area is evident by the presence of many thermal springs with temperatures that vary from 24 to 82 °C. In the waters of these springs, discharging along the normal faults bordering the graben, an abundant gas phase is bubbling. Loutra Ypatis is one of the emerging springs and its waters (31 °C) are exploited by a spa. The water is currently drained by a gallery and therefore the water level is about 5 m below ground at the bottom of a funnel-like hole (Fig. 1 left). For safety reasons the hole was covered by a closed building (Fig. 1 left and center). The gas, which is vigorously bubbling in the spring, is mostly (> 96%) composed of CO2 (D’Alessandro et al., 2014). The walls of the hole are covered of sulfur that derives from the partial oxidation of the H2S (2500 ppm) contained in the released gas (D’Alessandro et al., 2014). Methods In October 2015 atmospheric concentrations of CO2 were measured with a Licor LI820 NDIR spectrometer (range 0 to 20,000 ppm, accuracy of 2%), whilst in April 2016, the atmospheric concentrations of CO2 and H2S were measured with a Multi-GAS analyser manufactured by INGV-Palermo equipped with Licor LI-840 NDIR spectrometer (CO2 0-20,000 ppm) and an EZ3H electrochemical sensor by City Technology Ltd. (H2S 0–100 ppm) . Simultaneous CO2, CH4 (both 0-100%), CO, H2S (both 0-500 ppm) and O2 (0 – 25%) concentrations within the building were measured with a portable gas analyser GA2000 (Geotechnical Instruments). Results and discussion Due to the fact that a building covers the thermal spring, the intense bubbling activity of its waters creates a strong gas accumulation inside. The main component of the released gases is CO2, which has a higher density with respect to atmospheric air, thus creating the conditions for gas accumulation. About 2 m above the water level, CO2 concentrations of >95% and non-detectable O2 concentrations were measured. At higher levels above the water, CO2 concentrations were decreased but never below 50%. Such concentrations within the building are lethal for both animals and human beings. Of course, access is forbidden, but as the building is not perfectly sealed, the gases permeate to the outside through fissures and cracks. Figure 2 shows the CO2 concentrations measured in the air on October 2015 at 1.5 m height while walking around the walls of the edifice at about 2 m distance. Leaking of CO2 from the edifice is made evident by concentrations reaching values of more than 6000 ppm. The highest values were measured close to the entrance of the edifice were fissures and cracks are concentrated. Due to the tendency of CO2 to accumulate at lower levels, in this place, close to the ground, CO2 levels lethal to small animal can be reached. This was made evident by a dead bird found in that occasion (Fig. 1). In April 2016, due to the much windier conditions, CO2 concentrations at the same places reached values never exceeding 1000 ppm while H2S was always below 1 ppm. These values sharply increased getting closer to the fissures around the main entrance of the building and reached saturation of the sensors (CO2 > 20,000 ppm and H2S > 100 ppm) at a distance of few centimeters. The intense CO2 degassing observed at Loutra Ypatis may be responsible for elevated levels that can have an impact on human beings. It is worth noting that values measured in the atmosphere close to the building exceed the Occupational Recommended Exposure Limit of 5000 ppm (NIOSH, 2005). In closed spaces lethal levels can be easily reached. An older inhabitant of the close by village told us that in his childhood a playmate died by going inside the gallery that drains the thermal water out of the spa due to the high CO2 levels. Such episode underscores the need not to disregard the gas hazard created by intense natural gas manifestations like the thermal spring of Loutra Ypatis. References D’Alessandro, W., 2006. Gas hazard: an often neglected natural risk in volcanic areas, in: Martin-Duque, J.F., Brebbia, C.A., Emmanouloudis, D.E., Mander, U. (Eds.), Geo-Environment & Landscape Evolution II. WIT Press Southampton, Ashurst Lodge, Ashurst, Southampton, pp. 369-378. D’Alessandro, W., Kyriakopoulos, K., 2013. Preliminary gas hazard evaluation in Greece. Natural Hazard 69, 1987-2004. D’Alessandro, W., Brusca, L., Kyriakopoulos, K., Bellomo, S., Calabrese, S., 2014. A geochemical traverse along the “Sperchios Basin — Evoikos Gulf” Graben (Central Greece): origin and evolution of the emitted fluids. Marine and Petroleum Geology 55, 295-308 Daskalopoulou, K., Calabrese, S., Grassa, F., Kyriakopoulos, K., Parello, F., Tassi, F., D’Alessandro, W., 2018a. Origin of methane and light hydrocarbons in natural fluid emissions: a key study from Greece. Chemical Geology 479, 286-301. Daskalopoulou, K., Gagliano, A.L., Calabrese, S., Longo, M., Hantzis, K., Kyriakopoulos, K., D’Alessandro, W., 2018b. Gas geochemistry and CO2 output estimation of the Island of Milos, Greece. Journal of Volcanology and Geothermal Research 365, 13-22 NIOSH (2005) National Institute for Occupational Safety and Health pocket guide to chemical hazards. DHHS (NIOSH) publication No. 2005-149

ABSTRACT. Karst aquifers are considered to be one of the most important aquifer types, as they constitute the main drinking water resource for the majority of the global population (Ford et al., 2007). They are generated from the dissolution of carbonate rocks (e.g. limestone, dolomite, marble etc.), a phenomenon commonly known as “karstification”. This process is mainly caused by the acidity of water enriched in dissolved CO2, with the concentration of the latter being dependent on both the temperature and the CO2 partial pressure of the atmosphere in contact with the water (Bakalowicz, 2005). Carbonate rocks cover about 35% of the land surface of Greece and are mainly located in the western, central and southern parts of the country (Daskalaki et al., 2008). The Hellenic karst aquifer resources are more abundant in the western part of Greece, which receives the highest amount of precipitation (1800 mm/a) (Mimikou, 2005). The karst system constitutes a strategic resource of water in the region and preserving its quantity and quality is of the utmost importance for the sustainability of the area. Seventy samples of natural water were collected from karst springs in the northern (Macedonia-Thrace) and in the central parts of Greece, during 3 campaigns from 2016 to 2018. Sampling sites were selected on the basis of the springs flow rates (> 50 L/s). Water temperature, pH, Eh and electric conductivity were measured in situ with portable instruments; major ions were determined by Ionic Chromatography (IC) on filtered (anions) or filtered and acidified (cations) samples, whereas trace elements were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) on filtered and acidified samples. All analyses were performed at the laboratories of INGV of Palermo. Chemical compositions were compared with the limits fixed by the Directive 98/83/EC, which is the most recent EU legislation that sets quality standards for drinking water. Regulations concerning the quality of drinking water as established by the Directive allow Member States to adapt the monitoring of water quality to local conditions (Karavoltsos et al., 2008). Temperatures of the sampled waters ranged from 8 to 25 °C, pH from 6.5 to 8.4, whilst Total Dissolved Solids (TDS) from 206 to 15,418 mg/L. The highest concentrations of sodium, potassium, chloride and sulfate were found in the karst springs of Central Greece (26.6-5610 mg/L; 1.56-204 mg/L; 81.06-9467 mg/L; 15-2420 mg/L, respectively), where values had sometimes exceeded the limits set by the Directive 98/83/EC, indicating a contamination due to sea water intrusion. Based on the chloride concentrations, samples were subdivided into low (Cl- < 100 mg/L) and high (Cl- > 100 mg/L) chloride karst waters. All water samples were plotted in a Langelier Ludwig diagram (Fig. 1) with the low chloride waters presenting a typical alkaline-earth bicarbonate composition. Exception is the samples of Kaliakuda, Sidirokastro and Koromilia that display enrichment in alkalis possibly due to hydrothermal activity. On the other hand, the most chloride-rich waters plot close to the sea water composition point while two samples (Rema, Mylos Kokkosi) are aligned along the seawater-groundwater mixing line (Fig. 1). Concentration ranges of major and trace elements for all waters are presented in Fig. 2, with low and high chloride samples being plotted with different symbols. High chloride group displays much higher values for Mg, SO4, Cl, Na, K, Sr, B, Li, Rb and Cs with respect to low chloride, with differences in the median values between two and three orders of magnitude. Species deriving from carbonate dissolution (Ca and HCO3) show the lowest range of concentrations both for low and high chloride waters (Fig. 2). Low chloride waters show a wide range of concentrations (three to four orders of magnitude) for trace elements such as Li, Fe, Rb, As, Mn, Cu and Cs. Trace elements were above the legislation limits (Directive 98/83/EC) mostly in the case of high chloride karst springs, showing elevated concentrations of Boron (up to 1861 μg/L), Strontium (up to 5026 μg/L) and Arsenic (up to 12.1 μg/L). In terms of Boron and Strontium, the exceeding values seem to be generally related to the intrusion of sea water. On the other hand, Arsenic, whose maximum admissible level is 10 μg/L, was above limit also in the low chloride water (17 μg/L) of Tempi, Thessalia. Few low chloride waters show a metal enrichment, such as Tempi (Sr = 242 μg/L, Mo = 2.27 μg/L, and Cs = 1.57 μg/L) and Kaliakuda (V = 3.89 μg/L, Mn = 3.65 μg/L, Fe = 71.26 μg/L, Cu = 11.55 μg/L, Zn = 22.61 μg/L, Rb = 54.7 μg/L), whilst nitrate concentrations that could indicate contamination from fertilizers or from septic tanks, are always below the maximum admissible value (50 mg/L). Most of the analyzed waters can be considered suitable for human consumption. Water quality deterioration of Hellenic karst springs is mainly due to sea water intrusion, whilst only few low chloride waters show significant enrichments in trace metals that rarely exceeds the drinking water standards. These higher contents are probably of natural origin due to local geological setting.

References Bakalowicz, M., 2015. Karst groundwater: A challenge for new resources. Hydrogeology Journal, 13, 148-160. Ford, D.C., Williams, P.W. 2007. Karst Geomorphology and Geomorphology, John Wiley and Sons Inc. Daskalaki, P., Voudouris, K. 2008. Groundwater quality of porous aquifer in Greece: a synoptic review. Environmental Geology, 54, 505-513. Mimikou, M.A., 2005. Water resources in Greece: present and future. Global NEST Journal, 7, 313-322. Karavoltsos, S., Sakellari, A., Mihopoulos, N., Dassenakis, M., Scoullos, M.J., 2008. Evaluation of the quality of drinking water in regions of Greece. Desalination, 224, 317-329. EU, Council Directive 98/83/EC, 1998.

ABSTRACT. The present study deals with the the vein style Cu-Pb-Zn-Bi-As-Au mineralization hosted in the carbonates of Myriofyto, Kilkis district, N. Greece. The vein mineralogy, chemical composition, both of the veins and host rocks, as well as fluid inclusions study were performed in order to determine the origin of the mineralization.

ABSTRACT. Cave pearls are speleothems concentrically developed around a nucleus in shallow cave pools (Hill and Forti, 1997). Their name derives from their structure and appearance that commonly resembles pearls produced by mollusks. However, their shape varies greatly from spherical to cylindrical, cubic, hexagonal and disc-shaped. Their size can range from smaller than sand to about 20 cm in diameter and they can grow in few decades. They are commonly composed by calcite. However, the nucleus may be fragments of speleothems, rocks, organic material such as bones, wood etc. In contrast to most speleothems, cave pearls are not cemented on the substrate they are formed due to small occasional vibrations. Their shape, structure and texture is indicative of formation conditions. In Greece, cave pearls have been studied only in few caves (Dermitzakis et al., 1993). In this study a number of cave pearls have been sampled from the Almopia Speleopark caves (Lazaridis, 2005, 2006) in order to investigate their structure and composition. Methods The cave pearls have been divided into categories and the conditions of formation are interpreted according to Table 1. Electron microprobe analyses were carried out in the Scanning Microscope Laboratory, A.U.Th., using a JEOL JSM-840A Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS) with 20kV accelerating voltage and 0.4mA probe current. Pure Co was used as an optimization element. For SEM observations, the samples were coated with carbon - to an average thickness of 200 A° - using a vacuum evaporator JEOL-4X.

Table 1. Variation in the shape, texture and structure of cave pearls in respect to the corresponding conditions of formation (according to Hill and Forti, 1999 and references therein). Shape cubic, hexagonal round cementation to the floor formation of cave cup random conditions restricted precipitate supply, regular packing, calm mode of deposition or precipitation due to water freezing small size water pool level below the base water pool level below the top nucleus shape Texture smooth, polished surface rough surface conditions rapid water circulation slow water circulation Structure porosity variation conditions strong water agitation, composition, abnormal rates of precipitation, high temperature

Results In total, more than 70 specimens were measured and examined macroscopically. More than 10 specimens were cut in order to examine their internal structure and two were studied in SEM. Their large diameter ranges from about 6.6 to 47.3 mm. According to their shape and texture, they are divided in the following categories. • Round to irregular shape with smooth to polished surface; cave caps absent, their base may be less polished but smooth with facets due to contact with adjacent cave pearls. Small to intermediate size. Condition: Fast to rapid water circulation, possibly dense packing of cave pearls. • Oval-shaped with coarse surface covered by coralloids. Intermediate size. Condition: slow water circulation. • Oval-shaped with smooth to polished surface. Large size. Condition: Rapid water circulation, high water pool level. • Disc-shaped with smooth to polished surface. Intermediate to large size. Condition: fast water circulation, high water level. • Disc-shaped with coarse surface and cave cups. Their edge may be irregular. Intermediate to large size. Condition: relatively fast water circulation at early stages of development succeeded by a stage of pool level fluctuations. Regarding the nucleus of the examined cave pearls it has been found to consist of speleothem fragments, aggregate of fine-grained sediment, tooth fragment or coal. The latter has been found in cave pearls from the Bear Cave, where two samples of coal have been dated with radiocarbon in 4920-4720 B.C. and another in 5220-5050 B.C. (Kambouroglou et al., 2006).

As far as their structure is concerned, a variation in their porosity related to conditions seen in Table 1 has been noticed. In four out of six rounded to irregular shaped with polished surface pearls, layers of fine-grained clastic sediment are noticed. These layers are separating a more porous cave pearl from a less porous external layer. In three of those the nucleus consists of similar sediment. The other two cave pearls with polished surfaces are more porous close to the nucleus and the clastic sediment is absent. Another two cave pearls with irregular shape and coralloids on their surface have a porous part in their core and more dense external layers. Five disc-shaped specimens are more porous in comparison to the external layers of polished cave pearls. Their porosity varies among layers. The structure of a cave cup in some of them is clearly seen. Apart from the clastic material, only calcium carbonate was found in the layers of the analyzed specimens.

Figure 1. Cave pearls and their cross-sections: A. Almost rounded and polished cave pearl with porous core and probably dissolved nucleus; B. Almost rounded and polished cave pearl with clastic nucleus and one layer that separates internal relatively porous layers and external dense layers; C. Oval-shaped with coarse surface covered by coralloids and a more porous core; D. Disc-shaped cave pearls in situ; E. Longitudinal section of a disc-shaped cave pearl; dark layers on the upper half represent cave caps. Scale bar is 1 cm.

Conclusions Cave pearls in the Almopia Speleopark caves display a significant variation that depends on the sampling site and the conditions during their development. Despite their differences, specimens from the same chambers are clustered together according to their characteristics, such as shape, texture and structure or by similar nucleus. Based on the cave pearls with coal nucleus, it is estimated that their radius is increased with at least a mean rate of 1.2 mm/1000 years. References Hill, C.A. & Forti, P., 1997. Cave minerals of the world (2nd ed.). 1-463, National Speleological Society, Huntsville, Alabama. Dermitzakis, M., Tsipoura-Vlachou, M. & Basiakos, I. 1993. Cave-pearls: mineralogy and geochemistry. Bulletin of the Hellenic Speleological Society, 21, 140-158. Kambouroglou E., Bassiakos, Y., Bouzas, D., 2006. Paleontological-sedimentological excavational research in 2004 and dating results of Cave A’ Loutraki, Aridea, in: “The Archaeological Survey in Macedonia and Thrace”, 18 (2004): 573-589, Thessaloniki (in Greek with English abstract). Lazaridis, G., 2005. Speleological research in the loutra arideas area (Macedonia, Greece). –Neue Forschungen zum Höhlenbären in Europa, Naturhistorische Gesellschaft Nürnberg e. V., 45: 57-64, Nürnberg. Lazaridis, G., 2006. Almopia Speleopark (Pella, Macedonia, Greece): Morphology-Speleogenesis of the caves. –Scientific annals, School of geology, Aristotle University of Thessaloniki, Special Volume 98: 33-40, Thessaloniki.

ABSTRACT. The Fakos Cu-Mo-Au prospect, in Limnos island, NE Aegean Sea, comprises the first occurrence of porphyry-related tourmaline in Greece (Voudouris & Alfieris, 2005; Fornadel et al., 2012). The prospect is a telescoped porphyry-epithermal system hosted in lower Miocene alkaline to sub-alkaline igneous rocks and middle Eocene to lower Miocene sandstones. Tourmaline occurs within E-trending hydrothermal breccias and quartz-tourmaline veins related to quartz+sericite+tourmaline alteration of the Fakos monzonite, as well as disseminations within sericite-altered sandstones. This study presents EPMA data on the Fakos tourmaline and attempts to record any chemical differentiations, which may reflect variations of the ore-forming fluids. Tourmaline from the Fakos area is Ca-poor that is attributed to Ca deficiency in the host rocks. Tourmaline from altered sandstone and breccia cement have similar major exchange vector substitution FeAl-1 corresponding to isomorphic substitution Fe3+ ↔ Al and parallel to the OP trend, a featrure commonly observed in tourmaline from other porphyry deposits. Difference in excess charge value between tourmalines from sandstone and breccia cement may be explained by more reducing conditions of tourmaline crystallization in the breccia cement. Tourmaline from alteration adjacent to quartz-tourmaline veins is different in terms of composition and isomorphic substitutions compared to the previous two types. For these tourmalines, the compositions follow the FeMg-1 vector, which is quite unusual in tourmaline from porphyry systems, but rather represents a major exchange observed in tourmalines from mesothermal gold deposits, greisen, mesothermal tin deposits, and base metal deposits. This is in accordance with field observations at Fakos where quartz-tourmaline veins are transitional from the porphyry to the epithermal environment. Future work will focus on the tourmaline chemistry from Limnos and will be used as a possible vector towards new mineralized (Au-rich) centers in the broader area, as has been suggested for other tourmaline-bearing, porphyry-style alteration assemblages elsewhere.

ABSTRACT. Rare Earth Elements (REEs) are considered to be strategic metals, having a wide range of technological applications (e.g., Hatch, 2012). Due to high demand in industry and technology, the European Union (EU) has identified the study of REE resources as a top priority (e.g., Binnemans et al., 2018). As we are exploring for alternative REE deposits (e.g. Gamaletsos et al., 2019 and references therein), it is important to consider the environmental challenges associated with their exploitation, such as studying the spatial distribution of elements like thorium / Th (e.g. Gamaletsos et al., 2011). Eudialyte deposits, associated with peralkaline igneous rocks, are the dominant EU alternatives to currently exploited Chinese REE deposits from ion adsorption clays and carbonatites (e.g., Smith et al., 2016). Due to relatively low Th contents in peralkaline igneous rocks, typically sub-continental crust (<100 ppm Th), eudialyte exploitation could avoid potential issues of radioactive contamination in tailings that bedevil, e.g. monazite and xenotime extraction. However, the partitioning of Th and REEs at the micro-/nano-scale in eudialyte deposits is poorly studied. Here we utilize the technical advance of combining synchrotron radiation (SR) μ-XRF/-XAFS and electron microscopic (SEM-EDS/-WDS, EPMA, SEM-FIB, TEM/HRTEM) techniques (Fig. 1), along with LA-ICP-MS to study the local distribution of Th in one of the largest European eudialyte deposits, i.e. the Ilímaussaq Complex in South Greenland (Larsen and Sørensen, 1987). The Ilímaussaq complex is an oval-shaped peralkaline composite intrusion, part of the Mesoproterozoic Gardar province in South Greenland (Fig. 1). During at least four intrusive pulses, augite syenites, alkali-to-peralkaline granites, quartz syenites and volumetrically layered eudialyte-bearing nepheline syenites (“kakortokite”) crystallized (e.g., Larsen & Sørensen, 1987; Borst et al., 2019). The kakortokites comprise alkali feldspar, nepheline, sodalite, aegirine, arfvedsonite and eudialyte, with aenigmatite, rinkite-group minerals, fluorite, apatite and analcime as common accessory phases (e.g., Borst et al., 2018). Of particular economic interest are the eudialyte-group minerals (EGM), i.e. a group of complex Na-Ca-zirconosilicates which occur as major phases and contain wt.% significant concentrations of rare earth elements (ca. 2.5 wt.% REE2O3). A proportion of the primary EGM have been partially-to-fully replaced by fine intergrowths of variety of EGM alteration products (i.e. catapleiite, aegirine, nacareniobsite-(Ce) and other REE-rich secondary phases), resulting from late-magmatic hydrothermal alteration (e.g. Karup-Møller & Rose-Hansen., 2013; Borst et al., 2016). Preliminary SR (Fig. 2) and e-microscopic observations at altered EGM domains reveal the presence of Th-bearing phases at the micro-/submicro-/nano-scale. Similar micro-scale heterogeneity is observed for the REEs in eudialyte replacement products. We also collected Th LIII-edge μ-XAFS spectral data of Th-enriched micro-areas, previously identified by SR μ-XRF mapping that confirmed the heterogeneous distribution of the actinide, which provide information on the local structural environment of Th within altered EGM domains. Several Th-bearing phases were detected along altered margins of eudialyte, in secondary phases, and interstitial to primary phases such as feldspar, amphibole and eudialyte. In fresh magmatic EGM, Th is undetectable by SR μ-XRF; however, actinides are detected in fresh EGM crystals by means of LA-ICP-MS indicating very low concentrations typically below 40 ppm. Furthermore, LAICPMS detected all the REE, including Y and Sc in fresh EGM crystals. Significant variation of Ta and Nb and less of LREE in fresh EGM is recorded by LA-ICP-MS. HREE variations are within analytical uncertainty. Similar variation in Ce concentration was additionally recorded by SR μ-XRF mapping. The above variations might be associated with the sector zoning in fresh EGM as it is demonstrated by Borst et al. (2018). Regardless of low bulk contents of Th in peralkaline igneous rocks, we find localized relative enrichments of Th at the micro-/nano-scale associated with hydrothermal alteration products after rinkite and EGM, probably. Either thorium, which is enriched in the melt until the final stages of magmatic crystallization, partitions into the late-magmatic fluids at the hydrothermal stage as part of further cooling or it is redistributed from the eudialyte during alteration. Further research of how elements like Th, which are at low concentrations in bulk and are localized at the micro-/nano-scale, are transported and distributed within the ore and gangue minerals of peralkaline deposits will be important to inform and enhance the development of sustainable metallurgical processing routines for these ore types. Since traces of Th may be transferred into the metallurgical residues, the monitoring of its paths from the ore feed towards to the residues is needed.

ABSTRACT. Mineralogical investigation of Ermioni VMS iron caps revealed the high degree of supergene alteration with hematite and minor goethite being the major secondary phases identified, whereas only traces of pyrite and chalcopyrite relicts are still present. The supergene alteration zone at Roro is occasionally rich in secondary Cu phases (azurite and malachite) as a result of weathering of primary ore rich in chalcopyrite. At Karakasi, the samples from the supergene alteration zone show higher silica content relative to Roro, and the samples are very cohesive although highly porous, an observation that is related to the siliceous nature of the Karakasi primary ore. The supergene alteration zones of the Ermioni VMS mineralization are characterized by very limited Au enrichment that is related to both the small size of the primary ore bodies, and the very low Au content in the primary ore. The higher Au grades are identified in samples collected from Roro (approximately 0.7 gr/tn), whereas at Karakasi, the Au content of the supergene alteration zone is even lower (approximately 0.1 gr/tn). The presence of hematite with minor goethite in the Ermioni VMS oxidation zone is directly related to the presence of pyrite in the primary ore, but also to the predominant physicochemical conditions of the near-surface environment, indicating mildly acidic to alkaline and oxidative conditions. It is therefore reasonable to assume that as supergene alteration phenomena progressed, the geochemical environment of the Ermioni oxidation zone gradually changed from highly oxidative with increased sulfate load, to mildly acidic and oxidative with very low sulfate content.

ABSTRACT. The study was focused on the intermediate volcanoclastic conglomerate of the Perama Hill epithermal Au deposit. Mineralogical investigation of drill core samples revealed the presence of Au-Ag-Bi-Te-Se mineralization in several parts of the Perama Hill epithermal system, and in particular the southern and central part, where the main hypogene feeder zones are located. Relative to studies performed on the lower refractory ore, the intermediate volcanoclastic conglomerate is characterized by higher concentrations of precious metals, as evident by the presence of electrum (Au-Ag±Cu alloy), petzite (Ag3AuTe2) and hessite (AgTe2), whereas critical metal phases include native Bi and Bi-Te-Se phases. The relatively increased precious and critical metal load of the intermediate volcanoclastic conglomerate may be attributed to sudden changes in hydraulic conductivity between the lower and cohesive andesitic breccia (refractory ore) and the upper, unconsolidated and highly porous felsic sandstone. The absence of any evidence of supergene alteration further supports the hypothesis of hypogene origin of precious metals and in particular Au-Ag alloys.

ABSTRACT. The Agios Filippos deposit has been a target of exploitation for base metals (Pb, Zn and Cu), and only in recent years the presence of elevated concentrations of Critical and Precious Metals was revealed. In this study, mineralogical investigation of drill core samples from the Agios Filippos epithermal system revealed the presence of rare and uncommon Critical and Precious metal bearing phases including uraninite (UO2), cervelleite (Ag4TeS), marrite (PbAgAsS3), matildite (AgBiS2) and cuprobismutite (Cu10Bi12S23). Uraninite, marrite and cervelleite are identified at the upper part of the epithermal system, whereas matildite and cuprobismutite at the lower sector of the deposit. The presence of cervelleite, marrite and matildite in the system may indicate evolution from early high-sulfidation state to late intermediate sulfidation state. Concluding, these primary ore phases could provide further insights on the mode of formation of the Agios Filippos epithermal system and its correlation with the Northern Greece metallogeny, as well as further information on the Critical and Precious Metal potential of Greek mineral deposits and mineralizations.

ABSTRACT. In this study, we investigated the melt inclusions (MI) that are hosted in constituent minerals of the hypabassal rocks in Torud-Ahmad Abad magmatic rocks in south-south east of Shahrood (Northern part of central Iran structural zone) for the first time. Melt inclusions represent liquids that were trapped along growth zones (primary) or healed fractures of mineral phases, which crystallized from the silicate liquid as it cooled. Based on SEM analysis of these melt inclusions, their compositions are dacite, andesite and basaltic andesite. Thus, with the use of melt inclusions in the volcanic rocks of Torud-Ahmad Abad magmatic belt, we show the compositional evolution and origin of magma. The effective factors on evolution of these magma, are magma mixing, fractional crystallization and crustal contamination.

ABSTRACT. The investigated area is located in the Strymon basin (Macedonia, Northern Greece), which constitutes a typical post-orogenic graben of primary geothermal interest due to its favorable geological and tectonic conditions and the identified low enthalpy fields at the basin margins. Taking into account the existence of the Lithotopos-Iraklia low enthalpy (temperature) geothermal field east of Lake Kerkini (Strymon basin), a preliminary geothermal exploration was conducted by I.G.M.E. (nowadays Hellenic Survey of Geology and Mineral Exploration) northwest of Lake Kerkini. The exploration process included collection and evaluation of geological, tectonic and geophysical data, wellhead and downhole temperature measurements, water sampling and analyses from selected wells and geochemical assessment of groundwater.

ABSTRACT. Municipal, industrial and agricultural solid wastes continuously increase along with the human development. The management of such wastes is of major importance since it is associated with severe environmental impact. Until recently, in Greece the main solid waste management-treatment is landfill. Other waste management approaches include composting and recycling of wastes in the concept of circular economy, that are still in early stages in Greece. The participation of municipal solid waste (MSW) in the energy production under the so-called “waste-to-energy” scheme is gaining ground globally. The thermal processing technologies commonly used worldwide are incineration (combustion), pyrolysis and gasification. The benefit of the thermal treatment of wastes is triple: decreasing the waste volume, turning them into harmless material and producing energy. In Greece, the energy recovery from wastes by combustion has been recently regarded as a potential solution for the proper management of municipal solid wastes, due to its low cost and simple procedure (Athanasiou et al., 2015; Vamvuka et al., 2016). Olive oil industry solid waste is a recalcitrant waste and poorly biodegradable due to its relative high lignin content. Thus, common biological treatment is not sufficient for the management of olive oil waste. Olive oil waste have been utilized for bio-compounds recovery (Nunes et al., 2019) as well as alternative fuel (Morvová, 2017) and biogas production (Afif et al., 2019). The biogas production and product valorization are in general expensive and rather sophisticated processes. On the other hand, thermal processes are simple and have relatively low cost. The objective of this study is the investigation of the co-combustion of lignite with olive oil solid waste at different proportions as a potential alternative fuel with higher Gross Calorific Value (GCV). Two olive oil waste samples: a) extracted olive pomace (EOP) and b) olive stone (OLS) were collected from an olive mill in Katerini, Greece. Lignite (LIG) sample was collected from the mines of the Western Macedonia area, Greece. All samples were firstly air-dried for two weeks. Then, the samples were ground to size less than one millimeter (<1 mm). Eventually, they were dried in an oven at 80 oC for 24 hours. Raw EOP and OLS, and raw lignite as well as 3 different blends at proportions (waste-lignite) 30-70, 50-50 and 70-30 were prepared by mixing. Gross Calorific Values were determined in a Leco AC-500 isoperibol bomb calorimeter according to ASTM D 5865-13 standard (ASTM D 5865-13, 2013). Proximate analysis (moisture, ash, volatile matter and fixed carbon) of the samples was performed in a Leco TGA 701 device according to the ASTM D 7582 (ASTM D 7582-15, 2015). In Figure 1 the results of proximate analysis are presented. It is obvious that OLS and EOP samples exhibit much higher volatile content and much less ash percentage compared to lignite sample. High volatile matter is translated to higher heating capacity. This becomes apparent from the Gross Calorific values that are presented in Table 1. EOP has a GCV much higher than lignite and OLS exhibits almost double GCV compared to the respective value of lignite. Thus, it can be concluded that blends of lignite with solid waste from olive oil industry appears to be very attractive as alternative fuel. However, further studying is required in order to estimate and compare emission and pollutant capacity issues of such wastes.

Table 1. Gross Calorific Values (GCV) of all samples (EOP: extracted olive pomace, OLS: olive stone, LIGA: lignite) Sample ID GCV (MJ/Kg) EOP 19.63 EOP70 LIG30 17.02 EOP50 LIG50 15.78 EOP30 LIG70 14.28 OLS 22.30 OLS70 LIG30 18.96 OLS50 LIG50 18.58 OLS30 LIG70 13.54 LIGA 12.68

[Figure 1] Figure 1. Proximate Analysis of the raw pre-dried samples and their blends (EOP: extracted olive pomace, OLS: olive stone, LIGA: lignite)

Acknowledgements This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning» in the context of the project “Strengthening Human Resources Research Potential via Doctorate Research” (MIS-5000432), implemented by the State Scholarships Foundation (ΙΚΥ). References ASTM D 7582-15, 2015. Standard Test Methods for Proximate Analysis of Coal and Coke by Macro Thermogravimetric Analysis. ASTM International, West Conshohocken, PA. ASTM D 5865-13, 2013. Standard Test Method for Gross Calorific Value of Coal and Coke. ASTM International, West Conshohocken, PA. Afif, R. A., Linke, B., 2019. Biogas production from three-phase olive mill solid waste in lab-scale continuously stirred tank reactor. Energy 171, 1046-1052. Athanasiou, C., Tsalkidis, D., Kalogirou, E., Voudrias, E, 2015. Feasibility analysis of municipal solid waste mass burning in the Region of East Macedonia – Thrace in Greece. Waste Management & Research 33(6), 561–569. Morvová, M., Onderka, M., Morvová, M. Jr., Morva, I., Chudoba, V., 2019. Pyrolysis of Olive Mill Waste with On-line and Ex-post Analysis. Waste and Biomass Valorization 10, 511-520. Nunes, M.A., Pawlowski, S., Costa, A.S.G., Alves R. C., Oliveira, M.B.P.P., Velizarov, S., 2019. Valorization of olive pomace by a green integrated approach applying sustainable extraction and membrane-assisted concentration. Science of The Total Environment 652, 40-47. Vamvuka, D., Tsamourgeli, V, Zaharaki D. Komnitsas, K., 2016. Potential of poor lignite and Biomass blends in energy production. Energy Sources, Part A: Recovery, Utilization, And Environmental Effects 38, 2079-2085.

ABSTRACT. Synthetic nesquehonite (MgCO3·3H2O), a promising building material (Glasser et al., 2016), as recently gained interest as mineralization product of carbon capture and storage (CCS). The main advantage of nesquehonite in being a potential permanent storage solution for CO2 emissions is that at least 30% of its structure consist of CO32- (Ferrini et al., 2009). PHREEQC geochemical software has been recently proposed to be a useful tool in modeling CCS mineralization products (Liu et al., 2019). The aim of this study is to investigate the thermodynamic kinetics of CO2 mineralization and to determine the precipitation of nesquehonite in the ΜgO-CO2-H2O system applying the geochemical software PHREEQC (Parkhurst & Appelo, 1999, v. 3), and using data from laboratorial experiments. Nesquehonite was synthesized herein by mixing a rich in Mg2+ aqueous solution with a rich in CO32- one, at a temperature of 25 οC and pH 9.3, according to the following reaction: Mg2+ + CO2 (g) + 4H2O  MgCO3·3H2O (s) + 2H+ (1) Since during the reaction, pH was continuously decreasing, an additional input of alkaline solution (NH3) was required to keep pH in alkaline values (Ferrini et al., 2009). An important controlling factor of the amount of Magnesium (Mg)-carbonate minerals crystallized and precipitated by CO2 mineralization is the CO32- concentration in the solution reactant (Ferrini et al., 2009). For simulating the nesquehonite synthesis experiments with the geochemical software PHREEQC, Minteqv4 thermodynamic database (Allison et al., 1991) was used. Saturation Index (SI) of MgCO3·3H2O was calculated under different thermodynamic conditions in order to better study the precipitation/dissolution reactions of MgCO3·3H2O. SI of the solution is given by the equation: SI = Log (IAP / KSP), where IAP is the ion activity product; KSP is the equilibrium constant. When SI value is 0 the solution is in equilibrium with the mineral phase; when the SI value is >0 the solution is oversaturated, resulting in mineral precipitation, and when SI value is <0, the solution is undersaturated indicating that dissolution is required to reach equilibrium. The parameters evaluated herein were Mg2+:CO32- concentration ratio, pH and temperature. The precipitation/dissolution reaction of MgCO3·3H2O was investigated in a range of pH from slightly acidic to strong alkaline pH values (5-14) (Figure 1) and temperature values from 10oC to 80oC (Figure 2). Calculations were performed for 1.5M solution of Mg2+. MgCO3·3H2O precipitation may potentially take place in a range of thermodynamic conditions (Figures 1, 2) under different ratio concentrations of Mg2+ and CO32-. MgCO3·3H2O precipitation occurs from pH 7 to pH 13 in a temperature range from 10oC to 80oC, under different Mg2+:CO32- concentration ratio. The higher the Mg2+:CO32- concentration ratio of the initial solution is, the higher SI is. SI exhibits the highest value in slightly alkaline to alkaline pH conditions (pH 9.5-10). SI values in slightly acid to neutral (pH<7) and strong alkaline (pH>13.5) pH conditions are <0 indicating dissolution of nesquehonite (Figure 1). SI exhibits an upward inclined trend line with temperature increase (Figure 2) since KSP is highly dependent on temperature. As shown, the effect of temperature is less significant compared to the effect of pH. PHREEQC modeling of nesquehonite synthesis indicates that MgCO3·3H2O precipitation might occur in higher pH and temperature conditions than those referred to in previous studies.

ABSTRACT. Tinos chromitites appear in the ofiolite complex of Mount Tsiknia. The host rocks to the chromite orebodies are mostly serpentinites, meta-dunites, -peridotites, with minor -pyroxenites and locally-gabbros. Sampling included the ultramafic host rocks, i.e., serpentinites, meta-dunites, -peridotites, -pyroxenites, -gabbros and greenschists as well as the chromitites of the ofiolite complex. From these samples a total of 48 polished and thin sections have been studied with optical microscopy, Scanning Electron Microscopy (SEM) and selected samples have been analyzed for their major and trace elements.The ultramafic host rocks are dunites and harzburgites, typical of ‘depleted mantle’. Ore phases in intergrowths with chromite were identified, specifically of basic metal, sulfides and alloys, whether of primary or secondary origin. Tinos mineralization is related to the emplacement of Tinos composite granodiorite-leucogranite

ABSTRACT. The present graduate study refers to the research of the borate and the sulphate deposits of the Late Miocene basin of Karlovassi, west Samos Island, Greece. Borates, which are the main objective of the research, are the most important economic source of boron. This happens due to the fact, that boron is extremely dispersed in nature, averaging 10ppm in earth’s crust (Anovitz and Grew, 1996). As a result, there are relatively few occurrences where the element is sufficiently concentrated to be economic. Samos Island is located in the eastern part of the Aegean Sea and neighbors with the coast of Asia Minor-Turkey. The Karlovassi basin which is the main area of the research, is one of the two biggest sedimentary basins of Samos and has a North-South direction. Furthermore, the basement rocks of the basin are mainly marbles and limestones (Papanikolaou 1979). To be more specific, the basin was filled with basalt conglomerates, evaporites, marls, claystones and limestones. The Karlovasi basin has been predominated by hot and dry conditions during Late Miocene. These conditions led to the formation of a saline and alkaline lake (Stamatakis, 1986, 1989b). As it is known, borate salts and boric acid enrichments of supergene type occur mostly within recent playas-saline flats associated with volcanic emanations and hot springs (Helvaci, 2015). This criteria, along with older field and laboratory data on the occurrence of borates and celestine in the lake (Stamatakis and Economou, 1996), lead us to investigate in detail the Karlovassi basin, to locate any considerable amount of borate deposits that may be economically exploitable. For that reason, the aim of this study was to determine the borate deposits of this basin and draw the conclusions on the genesis and possible importance of the borates existed in that area. The borate mineral that has been found the most, is colemanite-Ca2B6O11•5(H2O) (Figure 1). Furthermore, ulexite is also present in some cases in smaller amounts with the form of needle-like crystals, with approximately 0.2mm size. Additional, celestine and barite crystals were found in the form of fissure fillings crossing the colemanite groundmass. Barite occurs rarely, covering celestine, as a fine-grained thin film of a few microns in thickness. Secondary calcite occurs replacing colemanite in micro and macro scale.

In the context of the present study, several depositional information, fieldwork observations and analytical lab results are presented. The field work included the sampling and investigation of the relationship of the borates with the host rocks. Moreover the analytical lab tests that have been carried out on the geological samples from the basin of Karlovasi were: • X-ray diffraction (XRD), which helped the identification of the mineral phases • Scanning Electron Microscope (SEM), which yields flexibility in the analysis of the geometry and composition of the microstructure of the individual mineral phases and their relationship • Optical Microscope Analysis (LM), which helped the identification of minerals in each rock sample through observation under magnification using both crossed and uncrossed nicols • Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), which is predominant in the analysis of major and trace elements • Stereoscopic microscope analysis, which helped to capture characteristic photographs providing very important information about the macro-structure of the mineral assemblages of the specimens All of the above tests were necessary in order to identify the presence of the borate and the sulphate minerals and the related minerals as well.

Afterwards, conclusions about the studied area and the depositional model are presented. Some of them are: • The Karlovasi basin is continental type and during Late Miocene it was a playa lake like environment similar to that of the Neogene basins of western Anatolia, Turkey. • The borate and sulphate deposits relate with the hydrothermal activity due to volcanism which took place in Late Miocene • The host rocks of the deposits are the tuffaceous rocks rich in Authigenic K-feldspar and zeolites and dolomitic claystone • The intense weathering of borate minerals in the basin of Karlovasi was reinforced by large-scale tectonic events that caused fractures in the sedimentary rocks of Upper Miocene and thus to the host rocks of the boron deposits. These data, combined with the rare occurrences of boron-bearing bodies found in this study, lead us to the conclusion that the probability of maintaining large borate mining bodies is limited • The only part of the basin which may have prosperity of further research by performing a drilling project is its NE part, where the Upper Miocene siliceous limestone-porcelanite cap rock is still preserved and may protect the borates from strong weathering that occurs in the rest of the basin.

ABSTRACT. Introduction and Objectives Clinoptilolite of sedimentary origin with ≥80 wt% clinoptilolite, ≤20 wt% clay minerals, free of fibres and quartz, can be used as feed additive for all animal species (EU Regulation No 651/2013, Filippidis et al. 2016) and consequently as nutrition supplement. In humans and animals, inhaled or injected or swallowed, fibrous zeolites (mainly erionite and mordenite, and to a lesser extent roggianite and mazzite), as well as the SiO2 minerals (quartz, cristobalite, tridymite), were found to be toxic, carcinogenic and highly pathogenic (Davis, 1993; Driscoll, 1993; Ross et al., 1993).

ABSTRACT. In this study the comparison of the cesium sorption ability between pulverized high quality HEU-type (clinoptilolite-heulandite) zeolitic tuff and pulverized heulandite crystals was examined. The experimental results showed that the cesium sorption ability of the HEU-type (clinoptilolite-heulandite) zeolitic tuff (sample NA11) was higher than this of the pulverized pure heulandite (HEU1). This is most probably due to the contribution of the nano/micro of the HEU-type zeolite (86 wt%) and the micas+clay minerals (4 wt%), as well as the meso/macro-pores of the zeolitic tuff to cesium cation sorption, while in the case of pure heulandite only the micro/nano-pores of the crystals contributed to the cesium removal from the solutions. The chemical composition of the zeolites (zeolite chemistry) can also influence their uptake ability. The cesium sorption ability was not significantly affected by the solution pH. The lower uptake value observed in the case of solutions with initial pH 2 is, most probably, due to the competition of the Cs+- with H+- cations. HEU type zeolites exhibit an amphoteric character having the ability to neutralize the solutions acting either as a proton acceptor or as a proton donor. Cesium is present in aqueous solutions of pH 2-12 always in Cs+ cationic form.

ABSTRACT. The production of zeolites is one of the potential applications of fly ash production to obtain high value industrial products with environmental technology utilization (Querol et al, 2001). The synthesis of zeolite products from fly ash is analogous to the formation of natural zeolites from volcanic deposits or other high-Si-Al rocks,rich in amorphous phases, by the interaction of hot alkaline water on the glass fraction of the rocks. That zeolite development process may take thousands of years in order to form natural zeolites. In the laboratory, the process can be speeded up (to days or hours) for both volcanic and fly ash. Previous studies have demonstrated the utilization of coal fly ash Na bearing synthetic zeolitic materials for the removal of heavy metals from wastewater (e.g. Koukouzaset al., 2010), for mine-water treatment (Itskos et al., 2015) and as soil amendments in acid mining soils (Giannatouet al., 2017, 2018). Since K is considered as a nutritient in agriculture (e.g. Stamatakis et al., 2016), in the present study KOH was selected as an activation solution, in order to develop a K-rich synthetic zeolite suitable for utilization in agriculture. In the current study we are evaluating the results of the hydrothermal activation of lignite fly and biomass asses from Greece, by KOH in order to produce synthetic zeolites, for agricultural applications. As KOH solutions present lower conversion efficiency than the respective NaOH under the same temperature (Itskos et al., 2015) the experimental conditions were modified from those proposed by Koukouzas et al. (2010) Itskos et al. (2015) and Giannatou et al. (2017, 2018), by using a 6N KOH as activation solution and extending the treatment period to 72h. Lignite fly ash samples from Meliti(MEL-FA) and Megalopoli(MEG-FA) Electric Power Stations and biomass ash from sawdust (SAWD-ASH), reed (REED-ASH) and olive kernel (OL-ASH) were used as raw materials that underwent the alkaline hydrothermal treatment at 100oC. The applied techniques mainly aimed at the dissolution of Al-Si bearing phases of the ashes and the subsequent precipitation of the zeolitic minerals. Both the initial materials and the final solid products, were subjected to X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM)study along with electron microbe microanalysis [Energy Dispersive System (EDS)] for the identification of their mineral phases at the Laboratory of Economic Geology and Geochemistry, National and Kapodistrian University of Athens. The cation exchange capacity (CEC) of the original and the hydrothermally treated materials had been determined in the same Laboratory. Furthermore,X-ray fluorescence analysis for the determination of the materials’ chemical changes after the thermalalkali digestion, has been carried out at the R&D Department of the Titan Cement Company. The synthetic zeolite produced by both lignite fly ashes was Zeolite-F. The cation exchange capacity of those synthetic materials is improved with respect to the initial ashes.Chemical and mineralogical properties of those lignite fly ashes treated, make them a suitable raw material for the synthesis of hybrid zeolitic products with upgraded potential for agricultural applications.On the contrary, biomass ashes failed to develop zeolitic material after the low temperature hydrothermal alkaline treatment due to their primary shortage of Al2O3. The synthesized Zeolite-F rich materials will be tested in the near future for their performance as soil amendments and slow release fertilizers.

ABSTRACT. The Velanida clay deposit composed of Fe-rich palygorskite and Mg-Fe-smectite rich clays, is situated within the so called “Ventzia” basin, located approximately 7 km southwest of the town of Eani in Kozani prefecture, Greece. This clay deposit lays unconformably on ultramafic rocks of the Vourinos ophiolitic complex and Mesozoic limestones of the Pelagonic Unit. The clay sediments were deposited in a fluvial-lacustrine rift basin formed during the Upper Pliocene – Lower Pleistocene period and grade east into the upper layers of the “Servia” Neogene basin that consists primarily of magnesium rich carbonates, dolomitic marlstone and sandstone (Stamatakis, 1995). According to a generic model by Kastritis et al., (2003), the initial sediment supply into the basin was mainly fine-grained serpentine sands and Mg-Fe-smectite clays that eroded from the saprolite bodies formed on the Vourinos ophiolite complex and the smectite-bearing sands of the Mesohellenic trench. During the closure of the basin sediment supply shifted, producing a high energy detrital deposit composed of carbonates mostly derived from the Triassic crystalline limestones located to the north of the deposit. Fe-rich palygorskite and Mg-Fe-smectite rich clays from the deposit were characterized by combining geological (stratigraphy), mineralogical, geochemical, sedimentological and micropaleontological data to better understand the depositional microenvironment and their related genetic mechanisms. In our study the main mechanisms of Velanida palygorskite formation were probably both, complete diagenetic transformation of Mg-smectite and partial dissolution of Mg-smectite followed by precipitation of palygorskite. Chemical precipitation from saturated solutions rich in Mg, Si and Al was much more limited and local.

ABSTRACT. We live in the era of growing industrialization and development of automotive industry. Those terms are undeniably related to an increasing demand for materials like crude oil and petroleum products. The everyday use, transportation and distribution of those substances unfortunately leads to an increase in the potential risks such as oil spills. Oil contamination is recognized as one of the major environmental issues nowadays with many consequences on the environmental and human health. The removal of oil leakages can be made by oil absorption process techniques using various absorbents. Natural mineral sorbents offers satisfactory results because of the ease of their use, their stability, their need for specific surface area and their low cost. Their remarkable performance is based on their ability to absorb and immobilize the substances without releasing them under pressure. The microporous structure and the sorption property that zeolites exhibit, make them a promising material for the removal of petroleum substances.

Sorbents can be classified as hybrid systems, as they can be employed for active removal as well as for containment, and are particularly effective in recovering traces of oil from both land and water. Also, sorbents are a class of materials which sorb oil either by absorption or adsorption. Past few decades have seen elaborate exploration of synthetic organic, inorganic, and natural organic sorbents, with a greater interest in the latter materials. Earlier observations showed the potential use of synthetic zeolites as sorbents of petroleum substances as individual so as additives for enhancing the product. Also, the use of expanded perlite in combating oil spills have been examined. Owing to their relative abundance, and due to the biodegradability of some of these, use of mineral sorbents has gained traction lately. However, no study has considered the comparison of natural and synthetic materials.

The goal of this study was to indicate the probability of microporous materials, examined globally, in order to compare and ensure the best possible solution with regard to the absorption of petroleum products. By comparing different grain sizes and most of all different materials we can have a comprehensive picture of their potential use. Both on the basis of the composition and on the basis of the structure of each material, behaves differently, as a result it has a different capacity in terms of absorption in general and in particular in petroleum products.

Three bulk samples of natural zeolites derived from different locations and one sample of synthetic zeolite derived from hydrothermal processing of fly ash were used. Particularly, natural zeolite samples were derived from the Greek islands of Samos and Kimolos (Z-SAM and Z-KIM), and Pitigliano, Tuscany Italy (Z-IT), whereas the fly ash was derived from Meliti Power Plant Station (SYN-Z). For comparison of the absorption capacity of the samples, a calcareous diatomite bulk sample was used, originating from Mytilinii, Samos Island, Greece (DIAT).

For the study, five different grain fractions of each natural zeolite material (s1 > 1mm, 1mm< s2 >500μm, 500μm< s3 >250μm, 250μm< s4 >63μm and s5 <63μm) were used in order to determine the most suitable grain size for such application. With regard to the petroleum products, were used two types of oil: (1) High viscosity oil (SHELL HELIX HX5 20W-50) and (2) Low viscosity engine oil used in SEM Siemens-5000 instrument.

The mineral composition of the sorbents was investigated by X-ray diffraction. The particle size distribution and specific surface area was measured with a laser particle-size analyzer. The specific surface area refers to the total area of the unit mass of the material. It is an important indicator for evaluating the adsorption capacity. The experimental procedure was the standard test method for oil absorption by spatula. Ιn particular, 3g of each solid absorbent material was placed on a 12x12 glazed surface and then the addition of the oil was made from the bottle drop by drop (using the glass tube) and after each addition was thoroughly mixed the oil and the sorbent by rubbing with the spatula. Continuing the addition of the oil till exactly enough oil has been incorporated to produce a very stiff paste that does not break or separate. The experiments were carried out in 3 repetitions.

Textural parameters such as BET surface area, pore volume, average pore width and the results of oils sorption of the investigated sorbents are summarized in the Table 1. The results of oil absorption capacity using the low viscosity oil were similar.

The results indicate that the sorption capacity of the investigated materials is controlled mainly by the textural parameters of the materials, especially specific surface area and diameters of pores. The studied zeolites differed in the contribution of micro- and mesopores in the surface and diameters of mesopores. In general, lower specific surface area and smaller grain fractions leads to lower oil absorption.

By comparing all the samples tested it’s evident that the material with the best absorption capacity was the natural zeolite from the island of Kimolos and especially the grain fraction <63μm that was able to sorb 1.8ml/g of high viscosity oil. That high sorption capacity may be related to the larger surface area.

According to the literature data all zeolite materials tested, could be assumed as functional in terms of their sorption capacity, with the finest grain fraction of Kimolos’ natural zeolite sample (Z-KIM s5) exhibiting the best performance.

It can be conclude that the narrow pores are less accessible for viscous substances and macromolecular substances such as oils. As far as the mineral composition is concerns, the result showed that oil absorption was highest by the natural clinoptilolite and motmorillonite mixture of the Kimolos’ sample). Diatomite was characterized by the lowest sorption capacity with respect to the tested substances. Notably, the analyses also indicate the potential use of synthetic zeolites from lignite fly ash for the removal of oil spills.

ABSTRACT. In the present study, a variety of different rock samples characterized by hydrous minerals, from Kos Island, South-East Aegean, were used to produce reflectance spectra in the VIS-NIR region. Kos Island (Dodecanese) is located in the eastern edge of the Aegean Volcanic Arc (Pe-Piper and Piper 2005). The geologic structure of the island is composed of various lithologies spanning the three main categories of rock classification: magmatic, metamorphosed and sedimentary rocks (Drinia et al. 2010, Soder et al. 2016, Kalt et al. 1998).The sampling performed on Kos (Iliopoulos et al., 2016) comprised a range of different lithologies and the main rock types included in this study are amphibolite schist, phyllite, phyllonite, monzodiorite, diorite, and altered diorite. The spectroscopic analysis is supported with petrographic analysis accompanied with microphotography and X-Ray Powder Diffraction analysis, aiming at first level to classify the samples into the main rock types, and secondly to contribute to the mineralogical recognition. Through this study we attempt to examine the spectral characteristics of these different lithotypes and the way that the mineralogy could affect the absorption features of each spectrum. The NIR spectra of altered diorites are dominated by the epidote and hornblende absorption features, however the percentage participation of the minerals plays an important role. The spectra from monzodiorite is characterized by the presence of amphibole which dominates the sample, with characteristic doublet features at ~2300 and ~2400 nm. As the biotite participation increases, even though the spectrum is characterized by the hornblende absorption features, it has a positive slope and a small sharp feature at ~2250 nm, indicative of biotite. The spectrum obtained from the phyllonite is characterized by broad rounded absorption features at ~1900 and ~2200 nm and that could indicate the presence hydrous, Al-rich minerals, like illite and muscovite. However, due to small percentage of phyllosilicate minerals and their brittle crystallinity as opposed to the siliceous minerals (quartz and feldspars), the characteristic absorption features in higher wavelengths (> 2300 nm) are subdued. Only a small, sharp feature at ~2290 indicate the presence of chlorite. The phyllite spectrum is characterized by the absorption features of mica. The intense absorption feature at ~2200nm is characteristic for illite-muscovite whereas the positive slope of the spectrum indicates the presence of Fe-rich minerals like biotite. The amphibole schist spectrum is characterized by absorption features both of amphibole (~2400 nm) and chlorite (~2250 and ~2300 nm).

ABSTRACT. Geoethics is an emerging multidisciplinary field dealing with problems of Ethics applied to the Geosciences. Geoethics consists of research and reflection on the values which underpin appropriate behaviours and practices, wherever human activities interact with the Earth system. Geoethics deals with the ethical, social and cultural implications of geoscience knowledge, education, research, practice and communication, providing a point of intersection for geosciences, sociology, philosophy and economy. In addition, geoethics represents an opportunity for geoscientists to become more conscious of their social role and responsibilities in conducting their activity in education, in research as well as in the daily professional life. On the other hand, geoethics is a tool to influence the awareness of society regarding problems related to geo-resources and geo-environment. In this presentation two important examples of geoethical issues will be examined: geonservation and public communication of georisks. The examination will be made from several perspectives including research, education, professionalism, applications and operations. The first is an excellent example referring to geoconservation with the Phalasarna geoarchaeological area in NW Crete taken as a case study. The other example is about the early warning systems for earthquakes and tsunamis and the geoethical issues they open for consideration

ABSTRACT. Introduction-Fossiliferous site The cercopithecid Mesopithecus is common in the late Miocene of Greece, recognized in several localities of the country. It was found in all Turolian localities of Axios Valley (Macedonia, Greece); two certain taxa M. delsoni and M. pentelicus, as well as a third one M. cf. monspessulanus have been described (Koufos, 2009a and references therein). The latter taxon was recognized in the material from the locality Dytiko 2 (DIT) by the mandibular fragment DIT-22 (Fig. 1c), which has smaller mandibular and dental dimensions than the typical M. pentelicus. The single known specimen and the badly preserved rest material from Dytiko 2 prevented a definite attribution and thus it was described as M. cf. monspessulanus (see Bonis et al., 1990; Koufos, 2009a, b). A re-examination of the Dytiko Mesopithecus sample allowed the recognition of another small-sized specimen from the locality Dytiko 1 (DTK). The specimen DTK-276 (it is wrongly mentioned as DTK-240 in Bonis et al., 1990: fig. 7, appendix 1) is a maxillary fragment in functional connection with the corresponding mandibular fragment and was not described. Recently, the maxillary and mandibular fragments of DTK-276 were separated (Fig. 1a, b), making possible to see their morphology, measure the teeth and make detailed comparisons. Three different fossiliferous sites are known from the area of Dytiko village, about 65 km northeast of Thessaloniki city, and all are situated into the Dytiko Formation, which consists of alternating yellowish-gray marls, sandy marls, gravels, and fresh-water massive marly limestones at the top (Koufos, 1990). They were biochronologically correlated to the late Turolian, MN 13; more exactly the faunal comparison with the well dated Late Miocene-Early Pliocene localities of Ptolemais Basin suggested an age between 7.0-6.0 Ma (Koufos & Vassileiadou, 2015 and references therein). The cercopithecids originated from Victoriapithecidae (Frost et al., 2017) and migrated to Eurasia from Africa during late Miocene; there are some discussed indications for their Vallesian presence, but they are certainly present at the beginning of the Turolian. The main Eurasian Late Miocene cercopithecid is Mesopithecus, expanded from the Iberian Peninsula to China. The earliest presence of Mesopithecus in Greece is mentioned from the locality Nikiti 2, NIK (Macedonia, Greece), dated at the beginning of early Turolian, MN 11 (8.7-8.2 Ma) (Koufos et al., 2016). The open, warm and dry environment of the Mediterranean region during Turolian was suitable for Mesopithecus, a semiterrestrial and opportunistic feeder, that often-consumed hard seeds (Merceron et al., 2009; Youlatos et al., 2012). The small and more arboreal form M. monspessulanus appeared later in the Pliocene (Szalay & Delson, 1979).

Figure 1. Mesopithecus monspessulanus, Dytiko, Axios Valley, Macedonia, Greece; Late Turolian, MN 13; a-b. Left maxillary (a) and mandibular (b) fragment, DTK-276 and c. mandibular fragment, DIT-22.

Description The maxillary fragment of DTK-276 preserves part of the left maxilla with the tooth row P3-M3 (Fig. 1a); the dentition is moderately worn, indicating an adult individual; the base of the zygomatic arc is well distinguished, and its anterior margin is situated above the M1 and M2 contact; the premolars are asymmetric (the P3 more than the P4) and bears two main cusps; the molars have the typical morphology of Mesopithecus with four main cusps. The mandibular fragment of DTK-276 preserves a small part of the mandibular corpus with the tooth row M1-M3 and that of DIT-22 the left mandibular corpus with i1-m3 and the beginning of the right mandibular corpus without teeth (Fig. 1b, c). The height of the mandibular corpus is small (~10.0 mm below the middle of the m2); the transverse torus is weak; the incisors are smaller than those of M. pentelicus; the premolars are asymmetric; the p3 has a single main cuspid; the p4 has two cuspids; large honing facet in the p3; the molars are not well preserved but they bear the Mesopithecus morphology and are smaller than those of M. pentelicus.

Comparisons The dental morphology of the Dytiko specimens is like that of Mesopithecus pentelicus and the differences are mainly restricted in the size between the two species. A principal component analysis of the lower dental dimensions of the Dytiko specimens in comparison with M. pentelicus from Pikerni and M. monspessulanus from Europe helps the attribution of the studied material. PC2 separates M. pentelicus from M. monspessulanus, while PC1 separates males from females in both taxa (Fig. 2a). The specimens DTK-276 and DIT 22 match with the males of M. monspessulanus. Therefore, the small-sized Mesopithecus from Dytiko can be definitely attributed to M. monspessulanus and the available material belongs to male individuals. Although the available sample of the upper dentition of M. monspessulanus is small, a similar analysis indicates that DTK-276 is out of the convex hulls of males and females of M. pentelicus from Pikermi. Moreover, the dimensions of the preserved lower canine of DIT-22 are close to the males of M. monspessulanus and smaller than the corresponding ones of male M. pentelicus (Fig. 2b), confirming the above attribution.

a

b Figure 2. a. Principal component analysis comparing the lower dental dimensions of DTK-276 and DIT-22 with M. pentelicus and M. monspessulanus; b. Scatter plot comparing the lower canine of DTK-22 with M. pentelicus and M. monspessulanus, symbols as in Fig. 2a. Data sources: PRIMO (https://primo.nycep.org/) for M. monspessulanus; personal dataset for M. pentelicus.

Remarks The re-consideration of the Dytiko small-sized Mesopithecus indicated that this material belongs to the small-sized M. monspessulanus a species which was unknown in Greece. Considering that: a) M. monspessulanus is known from the Pliocene of Europe, and b) the late Turolian, MN 13 age of the Dytiko localities, the studied material is the earliest evidence of this species in Greece. Based on the Turolian material of Mesopithecus in the Balkan Peninsula, there is a decrease in the size of the genus during that time span. The large-sized early Turolian M. delsoni continues with the middle Turolian M. pentelicus and then with the small-sized M. monspessulanus from late Turolian to Pliocene (Bonis et al., 1990; Koufos, 2009a, b). This early occurrence of the more arboreal form M. monspessulanus (see Szalay & Delson, 1979) agrees with the estimated environmental conditions (wetter with more closed microhabitats) in Macedonia, Greece during late Turolian and became more wet at the Miocene/Pliocene transition (Bonis et al., 1992; Koufos & Vasileiadou, 2015 and references therein).

Acknowledgements Financial support for comparative studies was provided to me by the European Commission’s Research Infrastructure Action (EU-SYNTHESYS: AT-TAF-702, FR-TAF-3102, GBTAF-1842) and the NSF-RHOI. Thanks to Mrs S. Veldemiri who separated the maxilla and mandible of the specimen DTK-276. I am indebted to A. Currant, G. Daxner-Höck, M. Harzhauzer, K. Heissig, S. Roussiakis, S. Sen, C. Soligo, P. Tassy and G. Theodorou, for giving me access to the collections at their disposal and for their great hospitality and help during my visit to their institutions.

References Bonis de L., Bouvrain, G., Geraads, D., Koufos, G.D.,1990. New remains of Mesopithecus (Primates, Cercopithecidae) from the late Miocene of Macedonia with the description of a new species. Journal of Vertebrate Paleontology 10, 473-483. Bonis, L.de, Bouvrain, G., Geraads, D., Koufos, G.D., 1992. Diversity and palaeoecology of Greek Late Miocene mammalian faunas. Palaeogeography, Palaeoclimatology, Palaeoecology 91, 99-121. Frost, S.R., 2017. Evolution of the Cercopithecidae, in Fuentes A. (ed), The International Encyclopedia of Primatology, 1-3. DOI: 10.1002/9781119179313.wbprim0064 Koufos, G.D. 1990. The hipparions of the lowerAxios valley (Macedonia, Greece). Implications for the Neogene stratigraphy and the evolution of hipparions, in Lindsay E., Fahlbusch V., Mein P. (Eds), European Neogene Mammal Chronology, 321-338. Koufos, G.D. (2009a). The Neogene cercopithecids (Mammalia, Primates) of Greece. Geodiversitas 31(4), 817-850. Koufos, G.D., 2009b. The genus Mesopithecus (Primates, Cercopithecidae) in the late Miocene of Greece. Bollettino della Società Paleontologica Italiana 48(2), 157-166. Koufos, G.D., 2016. Primates, in Koufos, G.D., Kostopoulos, D.S. (Eds), Palaeontology of the upper Miocene vertebrate localities of Nikiti (Chalkidiki Peninsula, Macedonia, Greece). Geobios 49(1-2), 45-51. Koufos, G. D., Vasileiadou, K., 2015. Miocene/Pliocene mammal faunas of southern Balkans: implications for biostratigraphy and palaeoecology. Palaeobiodiversity and Palaeoenvironments 95, 285–303. Merceron, G., Koufos, G.D., Valentin, X., 2009. Feeding habits of the first European colobine, Mesopithecus (Mammalia, Primates): evidence from a comparative dental microwear analysis with modern cercopithecids. Geodiversitas, 31(4):865-878. Szalay F. & Delson E., 1979. Evolutionaty history of the Primates, 1-580. Youlatos, D., Couette, S., Koufos, G.D., 2012. A functional multivariate analysis of Mesopithecus (Primates: Colobinae) humeri from the Turolian of Greece. Journal of Human Evolution 63, 219-230.

ABSTRACT. Well hidden in an intricate system of deep ravines crossing the Aliakmon River Valley is the fossil locality of Dafnero (Dafnero-1). Discovered in 1990 and originally explored between 1990 and 1994, the locality has yielded a limited but significant Early Pleistocene fossil mammal assemblage. A Greek-French partnership between the Aristotle University of Thessaloniki (Lab of Palaeontology) and the University of Poitiers (PALEVOPRIM), came back to this area in 2010 and started a new field campaign that soon allowed locating two additional fossil sites. Dafnero-3 has proven to be extremely promising in terms of quality and density of fossils and four years later a fairly complete skull of a large baboon-like monkey was unearthed. After seven years of intense field and lab work we provide here new data on the Dafnero fauna, flora, stratigraphy, and age, picturing altogether an astonishing mammal palaeocommunity at the gates of Europe

ABSTRACT. Presenting the KalPal Project The KalPal Project includes the study of microfaunal and macrofaunal skeletal elements from the Upper Pleistocene deposits of the Kalamakia cave in the Mani Peninsula, in order to extract conclusions on the palaeoenvironment and taphonomical history of the site. The cave was inhabited during the Middle Palaeolithic period by humans and, specifically, by individuals of the species Homo neanderthalensis, whose remains were also found during past excavations. The aim of the project is to identify the palaeo-ecological relationships between the different vertebrate species, including the Neanderthals, living in the area during the time of deposition and, at the same time, the taphonomic processes that affected the samples over time and how they defined the characteristics of the studied fossils. In addition, an attempt will also be made to identify the possible interaction between the people living in the cave with the animals from which the material originated. Study area Kalamakia cave is located 2km northwest of Areopolis, in the southern part of Itilo Bay, Mani Peninsula, southern Peloponnese. In this location, the vertical cliff that stands above the coast subsides leaving a small cove and, thus, creating a small plateau by the shore. The cave itself is located above that plateau (that is interpreted as a Tyrrhenean terrace) along with several smaller caves that surround it, either communicating with one another or not. The entrance, which is 7m wide and 8m long, lies at the foothill of a limestone cliffside 2m above sea level, 10m away from the shore, whereas the cave cavity is 20m deep. Excavations in Kalamakia were conducted from 1993 to 2006 by the Ephorate of Paleoanthropology and Speleology (Greek Ministry of Culture) in collaboration with the University of Athens and the Muséum National d’Histoire Naturelle (Paris) (Darlas et al., 1998). Former research The excavation in Kalamakia is one of the most important palaeontological / paleoanthropological excavations that have been conducted so far in Greece because of the skeletal remains of Homo neanderthalensis found in the cave (Darlas et al., 1998, 2004; Harvati et al., 2013). During the excavation, plenty of samples showed that the cave was used during the Middle Palaeolithic period, and more specifically 100-40 kya BP, as a periodic habitat of hunters and gatherers (Harvati et al. 2013). The identified large mammal fauna of Kalamakia comprises of 17 taxa. Fallow deer dominates the assemblage while ibexes and wild boars follow. Carnivores were also present, although low in numbers, throughout the stratigraphic sequence, with red fox being the most common species. The site also yielded the remains of several smaller vertebrate taxa, including abundant land tortoise remains (mostly Testudo marginata) (Darlas et al., 2008; 2016). A previous study of the microvertebrates of Kalamakia, especially rodents, indicated a generally open landscape surrounding the cave with dry and relatively warm climatic conditions (Roger et al., 2008). On the basis of both pollen and faunal data, during at least the first half of the last glacial, the climate in Kalamakia is considered to have been mild. The surrounding landscape was covered with maquis vegetation and some Mediterranean presteppic forest taxa (Lebreton et al. 2008). Material and Methodology Different approaches have been selected to decipher the scientific questions of this project and more specifically to provide palaeoecological interpretations, hence each subject of the project (lithic artifacts, microfaunal remains, macrofaunal remains examined taphonomicaly and animal teeth) follows its own protocol: Lithic artifacts: a digital application for the listing of archaeological material was created, in which the parameters were set according to the project’s priorities: stratigraphic origin, characteristics of the raw material, data on morphology, technology and typology. Microfauna: remains are observed stereoscopically and are identified taxonomically based on literature and the LPS’s comparative skeleton collection. Detailed lists for the identified fossils are kept for each specimen reporting the following: stratigraphic origin, type of skeletal element, relative position on the skeleton, taxon identified, preservation state. • Taphonomic and geochemical analyses of macrofaunal remains: for the evaluation of the site’s taphonomical history, the samples are examined macroscopically and microscopically using a stereoscope and scanning electron microscope, while taphonomical indices will also be calculated and analyzed statistically. For the geochemical study, samples are collected and examined under a scanning electron microscope, using nondestructive analytical techniques such as Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR) and of X-ray fluorescence (XRF) spectroscopy. • Microwear and mesowear study of ruminant teeth: The procedure for microwear analyses involves upper and lower second molar cleaning with acetone for the removal of dust, and also of any other chemical residues used in the field or during fossil preparation. Dental facets are molded and consequently photomicrographic scans are taken directly on the molds under a stereomicroscope in order to render the surface of the dental wear facets. For mesowear, the procedure has already been done by evaluating the occlusal relief and the cusp shape of the upper and lower molars (M1-M3, m1-m3) through digital photography with the aid of the software tpsDig2 2.17 (Fortelius et al., 2000). Results and Discussion So far, 20.500 lithic artifacts have been studied, 14.951 microfaunal specimens have been identified, 54 microfaunal and macrofaunal remains have been examined using X-ray fluorescence (XRF) spectroscopy and 134 samples of maxillar and mandibular specimens (from adult animals) were taken into account for mesowear analyses.

• As far as the type of the cultural material is concerned, stone-knapping from Kalamakia cave seems to have all the components that characterize the lithics in the area of Southeastern Europe during the Middle Paleolithic Age, but it also presents some particularities. What can be said with relative certainty, in relation to human occupation and activity in the cave, is that these were only periodical and that the exploitation of lithic resources was not the attractive factor for human groups (the vast majority of the raw materials are of poor quality and there is occasional use of "circumstantial" lithic backgrounds as tool materials, such as limestone raw material or core leftovers). • The results concerning the identifications of microvertebrates have revealed the presence of 3 different species of amphibians, 18 different reptile taxa, 3 insectivore species, 2 bat taxa and 6 rodent taxa through the whole sequence. From the taxa identified so far in the assemblage, the majority reflects an open environment. No species, considered typical of colder climates, have been identified yet leading to an estimate that the climate must have been relatively temperate during the depositional periods of the studied material. • The XRF results obtained so far from the examination of the bones from both small vertebrate and large mammal taxa, suggest that the main elements of the samples are calcium and phosphorus, obviously derive from the biomineral of bone (apatite). Nevertheless the enrichment in Fe, Al, Zn, Sr, Ba, Y and Sn at varying levels, is ascribable to the taphonomic processes that affected the bones post-burially. • Summary statistics for mesowear data for each taxon and among different strata have revealed a dietary range from browsing to mixed feeding strategy. The vast majority of the samples analyzed, belonged to Capra sp. and Dama sp. The predominant mesowear pattern over all strata among fossil samples of the two aforementioned taxa is high cusp relief associated with rounded cusp apices. Overall mesowear scores (Fortelius et al., 2000) in Dama sp. reflect a slight tendency to browsing but, in terms of average wear signal comparisons of Capra sp. and Dama sp. among different strata populations, it is rather reasonable to conclude that there were no siginificant variations through time. Acknowledgements The authors would like to thank Dr. Andreas Darlas, Director of the Ephorate of Palaeoanthropology and Speleology of Greece, for his consent to study the material and all his support during the ongoing studies and Dr. Eleni Psathi for her help with the study of the larger animals.

ABSTRACT. Cranial morphology of Late Miocene bovid species is presented, as part of a greater project, with the use of computed tomographic methods. The non-destructive nature of this method allows (3D) digital representation of cranial internal features of fossilized material in high resolution, thus giving the unique opportunity to examine otherwise inaccessible parts of the skull. The cranial internal structures of fossilized mammals are to this day one of the most poorly described features. Most studies of internal morphology concern extant species and the majority of them have focused on primates (Rae and Koppe, 2003; Farke, 2007, Rae, 2008; Kostopoulos et al., 2018; Miguel et al., 2018). Indeed, cranial sinuses – air-filled chambers resulting from the removal of bone by a pneumatic diverticulum – have yet to be studied for fossil taxa in order to assess their functional role (Edinger, 1950; Farke, 2010). Frontal sinuses, as part of the paranasal sinuses, are believed to form as pneumatic spaces that develop opportunistically where bone is not mechanically necessary, leading to reduction of the skull mass and so improvement of its performance (Curtis et al., 2014). Their function is not well understood, it has been suggested that frontal sinuses might aid the absorption of shock and/or dissipation of stress during feeding and combat (Badlangana et al., 2011; Farke, 2008; Snively and Theodor, 2011; Alsafy et al., 2013; Curtis, 2014). Fossil bovids from the Late Cenozoic are studied in order to extract data that will clarify the mysterious functions and evolutionary development of internal cranial features. Bovidae are used because of the exceptional diversity in cranial characters in terms of size and shape, which consists an excellent opportunity for identifying the most important morphological aspects. Furthermore, the Late Cenozoic consists a period with major climatic changes and variations, which put these animals under big selective pressure. Therefore, the most successful animals were those that were adapted to specific conditions, which possibly led to their diversification. This project is extensively using X-ray computed tomography. The skulls of several bovid species were chosen to be subjected to CT imaging. This method was chosen because it is the only high-resolution and non-invasive/non-destructive one available that provides information to inaccessible areas and structures of the skull. Additionally, it gives the opportunity to work on available Museum/University specimens, thus providing more information to the final results. Therefore, a Philips CT 64-slice tomographer from the Konstantopouleio General Hospital ‘Agia Olga’ and an Optima LG CT 64-slice tomographer from the University General Hospital of Thessaloniki ‘AHEPA’ were used. The CT data obtained are imported to advance imaging software (Avizo 8.1 and Mimics) to provide the digital reconstructions of the skulls internally and externally, that allow all digital measurements, volumetric and linear ones. The results will consist a base for further studies on other groups of mammals, both for the identification of the most useful morphological characters, and for the establishment of a novel methodological framework for this type of work. Lastly, the phylogenetic relationships of bovids will be analysed and provide an explanation of the morphological diversity of the recent species of the group. Herein we present an example of certain specimens that reveals these sinuses in their entity, and we comment on the expectations of this project in terms of interpreting the function of these features and whether these features add on phylogenetic interpretations.

Acknowledgements For access to material from Aristotle University of Thessaloniki and permission to CT scan them we thank Prof. D. Kostopoulos. Special thanks deserve to Dr. Maniatis P. and his team (especially to Dr. Moschouris P. and Dr. Tsipra E.) at the Konstantopouleio General Hospital ‘Agia Olga’ and Dr. Kalogera A. and her team at the University General Hospital of Thessaloniki ‘AHEPA’, both for giving us access to CT medical equipment. References Alsafy, M.A.M., El-Gendy, S.A.A., El Sharaby, A.A., 2013. Anatomic reference for computed tomography of paranasal sinuses and their communication in the Egyptian buffalo (Bubalus bubalis). Journal of Veterinary Medicine Series C: Anatomia Histologia Embryologia,Anat. Histologia Embryol., 42(3), 220-231. Badlangana, N. L., Adams, J.W., Manger, J.R., 2011. A Comparative Assessment of the Size of the Frontal Air Sinus in the Giraffe (Giraffa Camelopardalis). The Anatomical Record 294, 931–940. Curtis, A.A., Lai, G., Wei, F., Van Valkenburgh, B., 2014. Repeated loss of frontal sinuses in arctoid carnivorans. Journal of Morphology 276, 22-32 Curtis, A.A., 2014. A three-dimensional quantitative investigation of frontal sinus morphology and function in mammalian carnivores. Ph.D. Thesis in Biology, University of California, 128 p. Edinger, T., 1950. Frontal sinus evolution particularly in the Equidae. Bulletin of the Museum of Comparative Zoology at Harvard 103, 409-496. Farke, A.A., 2007. Morphology, constraints, and scaling of frontal sinuses in the hartebeest, Alcelaphus buselaphus (Mammalia: Artiodactlya, Bovidae). Journal of Morphology 268, 243–253 Farke, A.A., 2008. Frontal sinuses and head-butting in goats: a finite element analysis. Journal of Experimental Biology 211, 3085–3094. Farke, A.A., 2008. Function and evolution of the cranial sinuses in bovid mammals and ceratopsian Dinosaurs. Ph.D. Thesis in Anatomical Sciences, Stony Brook University. Farke, A.A., 2010. Evolution and functional morphology of the frontal sinuses in Bovidae (Mammalia: Artiodactyla), and implications for the evolution of cranial pneumaticity. Zoological Journal of the Linnean Society, 159, 988-1014. Kostopoulos, D.S., Guy, F., Kynigopoulou, Z., Koufos, G.D., Valentin, X., Merceron, G., 2018. A 2Ma old baboon-like monkey from Northern Greece and new evidence to support the Paradolichopithecus - Procynocephalus synonymy (Primates : Cercopithecidae). Journal of Human Evolution 121, 178–192. Miguel, R., Higgins, P. O., 2018. The biomechanical significance of the frontal sinus in Kabwe 1 (Homo heidelbergensis). Journal of Human Evolution, 114, 141–153. doi: 10.1016/j.jhevol.2017.10.007. Rae, T.C., Koppe, T., 2003. The term ‘lateral recess’ and craniofacial pneumatization in Old World monkeys (Mammalia, Primates, Cercopithecoidea). Journal of Morphology 258, 193–199. Rae, T. C., 2008. Paranasal pneumatization in extant and fossil Cercopithecoidea. Journal of Human Evolution, 54(3): 279–286. Snively, E., Theodor, J.M., 2011. Common Functional Correlates of Head-Strike Behavior in the Pachycephalosaur Stegoceras validum (Ornithischia, Dinosauria) and Combative Artiodactyls. PloS ONE 6:e21422

ABSTRACT. Introduction-Fossiliferous locality Mammoths originated in Africa at the end of the Miocene and during the late Pliocene migrated through the Levant to Eurasia, where they thrived until the Late Pleistocene. Eurasian mammoths show significant morphological adaptations through time, related to the general dietary trend from browse-dominated mixed feeding towards grazing, as a response to the changing environments of the Pleistocene (Lister & Sher, 2001). These adaptations are related to biomechanical advantages for grazing and increased resistance to abrasion, and are evident in skull and dental morphology: shortening and heightening of the cranium and mandible, enamel thinning, and increase in the height of the molar crown (hypsodonty) and the number of enamel plates in the molars (Lister, 1996). Μammoths (Mammuthus) are distinguished in Europe into four species: 1) a primitive morph, commonly, but tentatively, attributed to M. rumanus (early Villafranchian, late Pliocene); 2) the southern mammoth M. meridionalis (middle Villafranchian–Epivillafranchian, Early Pleistocene); 3) the steppe mammoth M. trogontherii (Middle Pleistocene); and 4) the wooly mammoth M. primigenius (late Middle–Late Pleistocene). Although most of the mammoth species are properly defined, the time and mode of the transitions/replacements are still open issues, and several intermediate/mosaic morphotypes or subspecies have been proposed by various researchers. Here, we conduct a preliminary study on the mammoth from Apollonia-1, and we discuss its evolutionary and biostratigraphic importance within the evolution of the Early Pleistocene European mammoths. The fossiliferous locality Apollonia-1 (APL) is located in Mygdonia Basin (Northern Greece), about 45 km east of Thessaloniki. The locality was discovered in 1991 (Koufos et al., 1992) and subsequently excavated in 1992–1996 and 2012–2014, and provided a wealth of mammal fossils. APL is situated within the Platanachori Formation (Pre-Mygdonian Group), which consists of sands, sandstones, conglomerates, silty sands, silts, clays, marls and marly limestones, indicating the local development of small lakes and swamps (Koufos et al., 1995). The APL fauna is younger than Dmanisi (~1.8 Ma; Georgia) and older than Untermaßfeld (~1.0 Ma, Epivillafranchian; Germany), showing similarities with Pirro Nord (1.5–1.2 Ma; Italy); therefore, a correlation to the second half of the late Villafranchian is possible for the locality.

Description-Comparison The APL sample includes a hemi-mandible with the third lower molar (m3) (Figure 1), an isolated m3, two isolated upper third molar (M3) fragments (Figure 2) and a maxilla fragment with deciduous dentition (DP2–DP3), the latter briefly discussed in Athanassiou & Kostopoulos (2001). The m3 of the hemi-mandible (Figure 1) is characterized by PN (plate number): >11, LF (lamellar frequency): 4.5 and ET (enamel thickness): 3.4; the M3 (Figure 2) by PN: >13, LF: 4.8, ET: 2.8 and HI (hypsodonty index): 1.48; the DP2 and DP3 bear 4 and 8 plates, respectively. The APL molars are different from those of M. rumanus, the latter having lower PN, LF and HI, and higher ET values. On the other side, the APL molars are also clearly outside the range of the M. trogontherii sample from its type locality Süßenborn (Germany) and the sample of M. primigenius from Předmostí (Czech Republic), which have higher PN, LF and HI values, and thinner enamel. The values of all these parameters of the APL molars are comfortably within the range of M. meridionalis, showing the diagnostic features of this species (Lister, 1996), and unambiguously indicate an attribution to the southern mammoth, in accordance with the morphology of the mandible, e.g., caudal border of the ramus posteriorly inclined (Figure 1). Within M. meridionalis, the APL molar sample is more derived than M. m. gromovi from Liventsovka (middle Villafranchian, Russia). On the other side, it is more primitive from the post-Jaramillo–pre-Brunhes specimens from Imola (Italy) and Dorst (The Netherlands) [both “M. meridionalis advanced” according to Lister et al. (2005) and Palombo & Ferretti (2005)], which show a higher HI in their M3s, within the range of M. trogontherii, and they could alternatively belong to the steppe mammoth as in the case of the Voigtstedt and Edersleben specimens (Germany; van Essen, 2011). The APL molars differ as well from the late Villafranchian M. m. tamanensis from Sinyaya Balka (Russia), which although it encompasses the APL HI value in M3, it shows an increase in the PN (Baygusheva & Titov, 2012). The APL mammoth fits well within the late Villafranchian M. m. meridionalis (typical) sample from Upper Valdarno (Italy), however, occupying its upper range in terms of PN, LF and ET, and slightly surpassing its HI values (data from Lister & Stuart, 2010). The best match of the APL molars is perhaps with the sample from the post-Upper Valdarno late Villafranchian localities from Italy, correlated to the Farneta Faunal Unit and attributed to M. m. vestinus by Azzaroli (1977) [although the validity of this subspecies is questioned (Palombo & Ferretti, 2005)], as well as with the Epivillafranchian (Jaramillo) M. m. depereti from St. Prest (France) sample, which however shows a wide range in its values. Finally, the eight plates of the APL DP3, combined with its large length, is unique so far within M. meridionalis.

Taxonomic and biostratigraphic conclusions The dentognathic remains of the APL mammoth permit its attribution to M. meridionalis. The relatively short and high mandibular corpus indicates a slightly more derived condition. The dental features also indicate an evolutionary stage somewhat more derived than the Upper Valdarno (beginning of late Villafranchian) mammoth in terms of the higher NP in the DP3 and the marginally higher HI in the M3. In this aspect, the APL mammoth fits better with corresponding specimens from localities correlated to the second half of the late Villafranchian and until perhaps the end of the Early Pleistocene. Whether this sample should be distinguished at subspecific level is open to discussion. These results are in agreement with the existing biochronological correlation of the APL fauna and further support the potential biostratigraphic significance of M. meridionalis within the Early Pleistocene, although conclusions based on limited/fragmentary sample should always be taken with caution.

Acknowledgements Research in Apollonia-1 was supported by the Research Committee of the Aristotle University of Thessaloniki (Projects 1396 and 87845) awarded to G. Koufos and D. Kostopoulos, and by the European Research Council StG 283503 (PaGE) awarded to K. Harvati. GK is supported by the European Research Council CoG 724703 (CROSSROADS) awarded to K. Harvati. References Azzaroli, A., 1977. Evolutionary patterns of Villafranchian elephants in Central Italy. Atti della Accademia Nazionale dei Lincei 14, 149-168. Athanassiou, A., Kostopoulos, D.S., 2001. Proboscidea of the Greek Pliocene-Early Pleistocene faunas: biochronological and palaeoecological implications. The world of elephants-1st International Congress, Rome, Italy, pp. 85-90. Baygusheva, V.S., Titov, V., 2012. The evolution of Eastern European meridionaloid elephants’ dental characteristics. Quaternary International 255, 206-216. Koufos, G.D., Syrides, G.E., Kostopoulos, D.S., Koliadimou, K.K., 1992. Apollonia, a new vertebrate site in the Pleistocene of the Mygdonia basin, Macedonia (Greece); the first fossil fresh-water mollusks in the area. Comptes Rendus Académie des Sciences Paris 315, 1041-1046. Koufos, G.D., Syrides, G.E., Kostopoulos, D.S., Koliadimou, K.K., 1995. Preliminary results about the stratigraphy and the palaeoenvironment of Mygdonia Basin, Macedonia, Greece. Geobios M.S. 18, 243-249. Lister, A.M., 1996. Evolution and taxonomy of Eurasian mammoths, in: Shoshani, J., Tassy, P. (Eds.), The Proboscidea: Evolution and palaeoecology of elephants and their relatives, 203-213. Lister, A.M., Sher, A.V., 2001. The origin and evolution of the woolly mammoth. Science 294, 1094-1097. Lister, A.M., Sher, A.V., van Essen, H., Wei, G., 2005. The pattern and process of mammoth evolution in Eurasia. Quaternary International 126-128, 49-64. Lister, A.M., Stuart, A.J., 2010. The West Runton mammoth (Mammuthus trogontherii) and its evolutionary significance. Quaternary International 228, 180-209. Palombo, M.R., Ferretti, M.P., 2005. Elephant fossil record from Italy: knowledge, problems, and perspectives. Quaternary International 126-128, 107-136. van Essen, H., 2011. Tracing transitions. An overview of the evolution and migrations of the genus Mammuthus Brookes, 1828 (Mammalia, Proboscidea). Ph.D. Thesis, Leiden University, Leiden, 270 p.

ABSTRACT. The accelerometric network of the National Observatory of Athens covers most Greek territory with 164 strong-motion stations. For few of those, site conditions are known in detail through measurements. However, most of them are still characterised merely through 1:50,000 geological maps. Considering: 1. the progress made in recent years with sophisticated ground motion models, 2. the move towards large open-access strong-motion databases, and 3. that Greek-provenance data represent a significant percentage of European seismic data, better site characterisation of this network’s stations has become imperative. In-situ-characterisation campaigns impose unattainable time/budget constraints, so we implement alternative approaches using the recordings themselves. We consider triggering-mode stations with an adequate number of recordings, and use the empirical horizontal-to-vertical spectral ratio technique to estimate amplification. The computed transfer functions show that the response within site categories as defined by seismic design codes (e.g. Eurocode 8) is often not homogeneous. The results shed light onto the seismic behaviour of particular stations and hope to aid in the quest for a more harmonised site characterisation throughout Greece.

ABSTRACT. Introduction Generalized Inversion Technique (GIT) first introduced and applied by Andrews (1986), consists a seismological “tool” where seismic source, site effect and propagation path spectral terms, is feasible to be separated from the Fourier Spectra of an S-wave earthquake record. The application of this technique requires a dataset of Fourier spectra based on a satisfactory number of seismic records from several common earthquakes and stations at a non-extended area. The last is theoretically considered so that the assumption of an average representative attenuation for the investigated area to be tested. Several studies have been achieved under this assumption by the application of the GIT, concluding in encouraging results about the three controlling terms (source, path, site), in comparison with other methods. Drouet et al. 2008a first applied the non-linear Gauss-Newton inversion method, at a parametric Generalized Inversion Technique in order to investigate for a set of earthquakes in France-Alps, the site spectral amplification where the recording stations were located and an average wave attenuation for the study area. In Greece the GIT method was applied by Drouet et al. 2008b, aiming at the estimation of the station site effect in Lefkas island and by Grendas et al. 2018 investigating seismic sources, average attenuation and site effect of the ITSAK (Institute of Engineering Seismology and Earthquake Engineering) accelerometric stations. The intention of this study is to introduce a reasonable way of spatially separating and studying the attenuation model. The goal of this effort is to improve the parameterization of the attenuation and consequently the GIT computing precision of the study parameters (seismic source, attenuation, site effect). At the end, a synthetic dataset was created and inverted by the new inversion algorithm that was developed following the one by Drouet et al. 2008a. Method GIT inversion developed here is based on the fundamental Eq. [1], where the first term of the product refers to the seismic sources (Brune, 1970), the second and the third refer to the attenuation and the last term consists the site effect. The product of these terms is equal to the Fourier spectrum Aijk of the S-wave record. The investigated parameters are the seismic moment Mo and corner frequency fc for each i earthquake, the γ(rij), Qsn and an parameters for the attenuation as mentioned below and the non-parametric site spectral amplification for the specific k frequencies at each station j. Gauss-Newton inversion algorithm (Tarantolla, 2004) uses the partial derivatives of Eq. [1] in relation to the above investigated parameters, as well as the initial values for these parameters and their corresponding a priori covariance values. Wave attenuation is controlled by the geometrical spreading and anelastic attenuation. The first one is analyzed and studied here as a distance dependent factor, controlled by a distance dependent gamma factor (γ(rij)) that is investigated (Eq. [1]). The second one is separately studied for the different n sub-divided areas (Figure 1b), controlled by the frequency dependent quality factor Qn(f) = Qsn f an, as well as by the specific epicentral distance rijn that passes through each specific “rectangular”.

Results & Conclusions The developed inversion algorithm in this work was applied to a synthetic dataset of 4313 spectra created by eq. [1] for 126 synthetic seismic sources (Mo and fc) “recorded” at 60 random stations with specific site amplifications, for 20 frequencies (0.5 -15 Hz). The initial values needed for the inversion method were considered to be unknown, taking reasonable initial values and quite large a priori covariance values. The only exception was the moment magnitudes that were considered to be the synthetic values affected by a random factor up to 0.2 as can be understandable in Figure 2a. The use of a priori known moment magnitudes, with their standard deviations (~±0.2) from different methods, for a real dataset is a common practice in GIT. Thus, affecting the synthetic values by a common computed factor up to 0.2, an actual practice was implemented. The results are encouraging enough for the correct process of the algorithm and also for the attenuation separation concept. This can be confirmed in Figure 2 where the source parameters results are presented. Inverted moment magnitudes Mw (corresponds to inverted seismic moments Mo), are equal to the synthetic Mw values (Figure 2a), as well as the computed corner frequencies, at least for Mw >2 corresponds to stress drop 100 bar, which is the synthetic stress drop value. For Mw < 2 the corner frequencies and stress drop are not well estimated in comparison to synthetic values, but this is more or less a reasonable result since the data are limited at frequencies up to 15 Hz and the inversion process can not easy compute corner frequencies greater than this limit. Attenuation parameters were computed close enough, with a short deviation, to the synthetic values, while site amplifications were computed satisfing enough, having the same “shape” but with a low underestimation as it is presented at Figure 3 for 5 of the 60 stations. It is worth noting that in case where some of the initial values were considered to be known, the final results were exactly the same as the synthetic values.

ABSTRACT. In the world of seismology,a major tool for seismicity study is the Gutenberg – Richter (G-R) relation whereby the G-R constants a and b are determined from earthquake catalogue to assess the seismicity of the region of interest. However the G-R relation does not accommodate information about the spatial coverage of the region concerned hence it will not suitably compare seismic activities of two or more regions that have unequal spatial coverage. Moreover, the method breaks down for any region where earthquake events are virtually of the same magnitude since constants a and b are indeterminate in this case. In addition the relation gives the rate of seismicity in terms of the total number N of earthquakes which makes a region having unusually few but large earthquakes to be underestimated. In this work,two mathematical models for rating seismicity in terms of radiated energy per unit area per unit time of earthquakes in a given region over a period of time were developed. One of the models takes care of situations where the G-R constants may not be defined. The two models were applied to ten regions in the world seismic zones. Both models rated the seismicity of the regions in the same order that is different from rating obtained from the a value of the G-R relation.

ABSTRACT. Tectonic activity is very difficult to study in the Santorini Volcanic Complex as it comprises a cluster of small/awkwardly shaped islands covered by pyroclastic deposits from which tell-tale markers are swiftly erased, while seismicity is generally absent. We address the problem by combining geophysical exploration methods to evaluate the long-term effects of tectonic deformation and time-lapse differential GPS to directly evaluate the magnitude and kinematics of present-day deformation. The former comprise 3-D gravity modelling to investigate the footprint of tectonics on the pre-volcanic Alpine basement and natural-field EM induction to map conductivity anomalies epiphenomenal to fluid circulation in faults. Our analysis identified the following principal tectonic elements: The Trans-Santorin Divide (TSD), a segmented NNW-SSE dextral strike-slip fault splitting the SVC sideways of the line joining Cape Exomytis, the Kammeni Islets and the Oia–Therassia Strait. It is collocated with a major vertical conductive zone and forms a series of dents and depressions in the basement. The Columbo Fault Zone (CFZ) is a pair of parallel NE-SW sub-vertical normal-sinistral faults straddling the northern SVC and terminating against the TSD; it may be associated with fluid injection into the shallow crust but appears to have limited effect on crustal conductivity (compared to TSD). The Anhydros Fault Zone (AFZ) is detected by its footprint on the basement, as a set of parallel northerly dipping NE-SW faults between the Athinios–Monolithos line and Fira. If it has any heave, it is left-lateral. It does not have distinguishable electrical signature and does not contribute to present-day horizontal deformation. The CFZ and AFZ are antithetic and form a graben containing the volcanic centre of Kammeni Islets. E-W extension was identified lengthwise of a zone stretching from Cape Exomytis to Athinios and along the east flank of the caldera to Imerovigli. N-S normal faulting confirmed therein, may have contributed to the localization of the east caldera wall. NNE-SSW compression was observed at SW Thera; this may have produced E-W failure and contributed to the localization of the south caldera wall. The footprint of the caldera on the basement is a parallelogram with N-S long and WNW-ESE short dimensions: if the east and south flanks collapsed along N-S normal and E-W inverse failures, then the west and north flanks may have formed analogously. Present-day deformation is localized on the TSD and CFZ: this can only be explained if the former is the synthetic (dextral) Riedel-R shear and the latter the antithetic (sinistral) Riedel-R shear, generated by N-S 1 and E-W 3 principal stress axes. Accordingly, NW-SE right-lateral shearing of the broader area is expected and indicated by several lines of indirect evidence. The geographic extent of this shearing and its role in the regional tectonics of the south Aegean remains to be confirmed and appraised by future research. Contemporary volcanic centres develop at the interface of the TSD with the CFZ/AFZ graben; volcanism appears to be controlled by tectonics and the SVC to be shaped by tectonic rather than volcanic activity.

ABSTRACT. A strong earthquake with magnitude M6.3 struck on June 12, 2017 the island of Lesvos and the surrounding area, situated at the north-east part of the Aegean Sea. While the mainshock epicenter was estimated to be ~15 km off the southern coast of Lesvos island with a focal depth to 12 Km, relatively limited damage was reported along the coastal Lesvos area. An exception was the historical settlement of Vrisa, where extensive damage (including a large number of collapsed masonry houses) was observed, mainly in the northwestern part of the village, which was located on recent (Holocene) sediments. On the contrary, for the remaining part of the village, founded on stiffer Neogene deposits, limited damage was reported. Moreover, the earthquake affected mainly the historical, masonry buildings of the village, with a negligible impact on the (fewer) reinforced concrete modern constructions. To explain the presence of such localized damage phenomena, we employ the stochastic finite-fault modelling approach of Motazedian and Atkinson (2005), as adapted by Boore (2009), for the simulation of Fourier Amplitude Spectra (FAS) of the 2017 Lesvos earthquake. To calibrate the necessary model parameters of the stochastic finite-fault method, we used waveform data from both acceleration and broadband-velocity sensor instruments within ~100km from the earthquake fault. To constrain the mainshock focal parameters, we have computed an updated 1-D velocity model for the study area following Kissling et al. (1994), and relocated the Lesvos 2017 aftershock sequence in order to determine the main geometrical features of the earthquake’s fault. Preliminary relocations were performed with the HYPOINVERSE (Klein, 2002) program, and hypoDD (Waldhauser, 2001) relocations allowed to obtain an improved aftershock sequence distribution. From the relocation procedure we constrained the main fault dimensions, strike and dip, in good agreement with fault plane solutions published for this event, and used them in the stochastic simulation approach. Using the previous source information, as well as appropriate path and generic site-effect information for the Aegean area, we solved for the mainshock stress-parameter value, in an attempt to fit the FAS of the mainshock recorded waveforms. To estimate the stress parameter (Δσ), we adopted a trial-and-error approach and tested different stress-drop values, through comparison of simulated and observed acceleration Fourier spectra. Since the previously described damage pattern for the Vrisa settlement is indicative for the presence of strong site-effect phenomena, we have employed a large number of surface geophysical measurements, recording mainly of surface waves from both active and passive sources, in order to study the shallow geophysical structure and examine the spatial distribution of the expected site effects on seismic motions for the Vrisa area. To determine the 1-D shear-wave velocity structure, a circular Noise-Array was realized in the northern (Holocene) Vrisa area (with a radius of 10, 40 and 100 m for the inner, the middle and the outer circle radius, respectively). Moreover, 23 lines of MASW were realized with the use of 4.5 Hz vertical geophones. This dataset was complemented by the performance of nearly 70 single station ambient noise measurements, which were conducted with the use of broad-band seismometers (CMG-6TD or CMG-40T-60 sec with Reftek 130 digitizers). Horizontal-to-Vertical Spectral Ratio (HVSR, Nakamura, 1989) curves were calculated for all noise recording sites, while dispersion curves were determined with the use of the f-k method, both for the MASW and the Noise-Array data. For the final 1-D shear-wave velocity model determination we employed a joint inversion of Rayleigh wave dispersion curve and Rayleigh ellipticity information. For this reason, Rayleigh wave ellipticity was extracted from the noise recordings using the approach of Hobiger et al. (2009). Ellipticity was jointly inverted with the reconstructed Rayleigh dispersion curves, in order to increase the Vs-model penetration depth, as well as to reduce the non-uniqueness of the model inversion. The joint inversion was performed with the use of a Monte-Carlo approach, namely the neighborhood algorithm, as adapted by Wathelet et al. (2008) and realized through the Geopsy software tools (http://www/geopsy.org). The final Vs models (figure 1) show the presence of a very soft layer (Vs<300 m/sec, in most cases <200m/s for the uppermost 10-15m), with a typical thickness of ~20-25 m for the northwestern part of Vrisa, clearly corresponding to the Holocene formations of the study area. This layer is underlain by a stiffer layer (Vs>500 m/sec, locally >700-800m/sec), which outcrops in the Vrisa southeastern section, corresponding to the Neogene formations. The transition from Neogene to Holocene formations is rather abrupt, suggesting the presence of a NE-SW normal fault that creates the local basin, which is filled with Holocene formations. Preliminary 1D site response analysis in the frequency domain for the final geophysical model of the Vrisa area confirms the presence of strong amplification of seismic motions in the northwestern Vrisa area, in good agreement with the damage pattern of the June 12, 2017 M6.3 earthquake. The HVSR results revel a strong spatial variation of the soil fundamental frequency, f0, and maximum HVSR amplitudes, A0HVSR, with almost flat HVSR curves in the southeast Vrisa (Neogene sediments) and large A0HVSR values (locally larger than 5) in the Holocene sediments at frequencies f0~2.5-3 Hz. Considering that A0HVSR values generally provide a low threshold of local amplifications, we expect seismic motions to be significantly amplified in the Holocene sediments section of the village. This was confirmed by computing Standard Spectral Ratios (SSR, Borcherdt, 1970) from aftershock records in both Neogene and Holocene deposits, which showed that peak amplifications, A0, are almost double than the values provided by A0HVSR, though the resonant frequency, f0, and spectral shapes of the SSR and HVSR curves were nearly identical. The spectral slopes (Anderson and Hough, 1984) were computed for all the sites with aftershock records, in order to compute kappa factors and the SSR curve correlations. By quantitative comparison of the HVSR and SSR results for several sites it was possible to determine an appropriate scaling factor and reduce all HVSR curves to equivalent SSR curves. Using these equivalent SSR amplifications, we employed the stochastic simulation method for the determination of complete ground motion simulations throughout a dense virtual receiver grid in the Vrisa area, and reconstructed the detailed spatial variation of several ground motion measures (PGA, PGV, etc.), as well as expected damages (IMM) in the broader Vrisa area. The results show that the while the southeastern part of the Settlement (Neogene deposits) exhibited values around IMM=6+ to 7, the northwestern Holocene section experienced damage levels of the order of IMM=8+ to 9, in excellent agreement with the observed damage distribution. References Anderson, J.G., Hough, S.E., 1984. A model for the shape of the Fourier amplitude spectrum of acceleration at high frequencies. Bulletin of the Seismological Society of America, 74(5), 1969-1993. Boore, D.M., 2009. Comparing stochastic point-sou rce and finite-source ground-motion simulations: SMSIM and EXSIM. Bulletin of the Seismological Society of America, 99(6), 3202-3216. Borcherdt, R.D., 1970. Effects of local geology on ground motion near San Francisco Bay. Bulletin of the Seismological Society of America, 60(1), 29-61. Kissling, E., Ellsworth, W.L., Eberhart‐Phillips, D., Kradolfer, U., 1994. Initial reference models in local earthquake tomography. Journal of Geophysical Research: Solid Earth, 99(B10), 19635-19646. Klein, F.W., 2002. User's guide to HYPOINVERSE-2000, a Fortran program to solve for earthquake locations and magnitudes, USGS Open-File Report 2002-171, https://doi.org/10.3133/ofr02171 Hobiger M., Bard P-Y, Cornou C., Le Bihan N., 2009. Single station determination of Rayleigh wave ellipticity by using the random decrement technique (RayDec). Geophys. Res. Lett., 36, doi:10.1029/2009GL038863. Motazedian, D., Atkinson, G.M., 2005. Stochastic finite-fault modeling based on a dynamic corner frequency. Bulletin of the Seismological Society of America, 95(3), 995-1010. Nakamura, Y., 1989. A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface. QR Railway Tech. Res. Inst., 30(1), 25-33. Waldhauser, F., 2001. hypoDD--A program to compute double-difference hypocenter locations. Wathelet, M., 2008. An improved neighborhood algorithm: Parameter conditions and dynamic scaling. Geophys. Res. Lett., 35, doi:10.1029/ 2008GL033256.

ABSTRACT. In this work we present the results of the geophysical survey that took place in 2018 at the Katakolo peninsula aiming into obtaining supplementary information regarding the subsurface geological configuration of the wider Katakolo peninsula. The main aim of the geophysical survey was to determine the thickness of the top Katakolo formation and to investigate the possible existence of salt diapir below the wider Katakolo peninsula area up to a depth of 500m. The technique of electrical resistivity tomography was applied over the entire Katakolo Peninsula to map the subsurface at depths up to 250m in order to locate geoelectrical units and discontinuities and then correlate them with the geological/geotectonic setting of the area. Additionally, a large number of Transient Electromagnetic (TEM) method soundings were collected and interpreted in an attempt to map the deeper geoelectrical structure (i.e. up to 500m depth) of the peninsula and locate possible diapir intrusions. The geoelectrical survey results illustrate clearly that the thickness of the Katakolo formation is limited at the south-eastern and south parts of the peninsula but it increases significantly towards north-west. The particular change in thickness seems to be also related to the existence of tectonic lines. The interpretation of all TEM soundings showed no evidence of a salt diapir intrusion in the whole area of investigation. This result applies for the first approximately 500 m of depth, within which the results are considered as reliable.

ABSTRACT. Introduction The Alpine-Balkan-Carpathian-Dinaride (ABCD) metallogenic and geodynamic belt is considered Europe’s premier Pb-Zn-Cu (-Mo-Sb-Ag-Au) province. It is divided in three spatially and temporally distinct tectonic and metallogenic belts. One of them, the Serbomacedonian-Rhodope Metallogenic Belt (SRMB), intersects with a NNW-SSE trend south-western Serbia, Kosovo, F.Y.R.O.M., north-eastern Greece and south Bulgaria. This arcuate belt is about 500 km long and 130-180 km wide. Deposits of carbonate-replacement Pb-Zn-Ag-Au, of porphyry Cu-Mo-Au, of stratiform volcano-sedimentary, of isolated magmatic-hydrothermal and skarns, as well as intrusion-related, epithermal and Carlin-type, compose this belt. All are genetically related to Oligocene-Miocene post-subduction magmatism (Kalogeropoulos et al., 1989; Marchev et al., 2005; Serafimovski et al., 2010; Tsirambides & Filippidis, 2016; Voudouris et al., 2018). Native Bi is a relatively common mineral, native Sb is less abundant, and Sb-Bi alloys are relatively rare phases in nature. Sb-Bi alloys and Ag-Cu-Pb-Sb-Bi sulfosalts have been discovered in some metal assemblages in the SRMB. Stibnite (Sb2S3) is the predominant ore mineral of Sb. The most important ores of Bi are bismuthinite (Bi2S3) and bismite (Bi2O3). Trace metallic minerals like Bi-sulfosalts and Bi- sulfotellurides, precious- and base metal tellurides are usually associated with Au-bearing ores and can be considered as pathfinder minerals for Au (Melfos & Voudouris, 2012). The European Union (EU) is highly dependent on critical and rare metals which are very important for a sustainable development. However, European industry is not able to cover its demands from native sources and it imports commodities from third countries. The various types of deposits of the SRMB are promising targets for future exploration and exploitation in Sb, Te, Mo, Re, Ga, In, REE and PGE. Therefore, the mineral wealth of this belt can contribute significantly to a sustainable and a competitive economy of Europe (Tsirambides & Filippidis, 2012, 2016).

Results and discussion The Au-As-Sb-Tl Alshar deposit of Carlin type in F.Y.R.O.M. is located at the intersection of the Axios (Vardar) and Aridea-Kozuf metallogenic zones at the western side of the Vardar Graben and the Pelagonian crystalline massif, approximately 3 km from the Greek-F.Y.R.O.M. border. The deposit is composed of several ore deposits and occurrences, which are characterized by specific assemblages of elements and minerals. More than 40 minerals have been identified in this ore deposit. Stibnite occurs in the form of crystals up to 2 × 5 mm in size and frequently cements quartz and marcasite grains, indicating its younger age in comparison to pyrite–marcasite assemblage. A probable temperature of about 200°C is accepted for the formation of the main Au-ore. The Alshar deposit is undoubtedly related to the action of post-volcanic hydrothermal fluids. The ore field covers an area of 21 km2. It is considered a very significant deposit containing economic grades of Sb (up to 2.5 wt%), As (up to 1.5 wt%), Tl (up to 0.5 wt%) and Au (about 1 g/t). The indicated stibnite reserves exceed 20,000 t (av. Sb=0.5 wt%) (Volkov et al., 2006). In the regions of Macedonia and Thrace in Greece there is a large number of occurrences and ores of Pb, Zn, and Cu, which are often accompanied by Mo, Sb, Bi, W, Ag, Au and other metals. Some of these ores are economically very significant. Except stibnite, antimony is also contained in many sulfosalts which are common in porphyry-, epithermal- and intrusion-related systems at the Rhodope Massif. In some cases samples contain up to 0.2 wt% Sb (Voudouris et al., 2011; Melfos & Voudouris, 2012; Tsirambides & Filippidis, 2016). The Vertiskos Unit of the Serbomacedonian massif (SMM) hosts several Oligocene-Miocene ore deposits and mineralization occurrences. Some of these contain significant amounts of metals such as Sb, Bi, Te, Co, REEs and PGMs. At the northern part of the SMM there are porphyry-epithermal (Vathi, Palatiano, Gerakario, Pontokerasia, Doirani), skarn/carbonate replacement (Myriofyto, Petrades, Monolithi) and epithernal vein (Rodonas) ore type occurrences (Stergiou et al., 2018).

ABSTRACT. The Ermioni host volcanics are gray-green in color, cohesive, indurated and massive, and geochemically range between basalts and andesites. The mineralogy is rather monotonous, with predominant angular to subangular coarse-grained albite crystals after alteration of primary Ca-plagioclase. The matrix is dominated by fine-grained chlorite, epidote, prehnite – pumpellyite and minor quartz, whereas angular to subangular clasts of mafic volcanics with plagioclase microlaths are also observed. Based on the textural features, the Ermioni host volcanics may be described as mafic volcanic tuffs. Hydrothermal propylitic alteration is evident by the presence of prehnite – pumpellyite ± quartz, and quartz – epidote veins and veinlets that cut the host volcanics, which in turn are cross-cut by late stage coarse-grained quartz and quartz – calcite veins. The trace element geochemistry of the Ermioni host volcanics is characteristic of a supra-subduction zone setting in close proximity to the continental margin, as identified by the high silica content of the Ermioni host turbidites, and show similar trend to island arc volcanic rocks, with moderate LREE and relatively constant HREE values. A different geotectonic setting of volcanism relative to the typical geotectonic setting of ophiolites that host Cyprus-type mineralizations, is proposed, and according to host rock lithology, mineralogy, texture and geochemistry, there are strong arguments for classification of the Ermioni VMS mineralization as “Besshi-type”.

ABSTRACT. The present research studies the epithermal type veins intruding andesites of the Kornofolia area in Evros, Greece. The veins mainly consist of quartz, calcite, chalcedony and three types of opal (milky white, transparent and green). FT-IR analysis that was performed on the three opal types displayed variations on their crystal structure. Further investigation concerning the fluid inclusions in quartz and calcite will be conducted.

ABSTRACT. The rare earth elements (REEs) have been characterized by European Union (EU) as critical raw materials with a significant risk of supply due to their wide utilization in many new technological applications. The growing demand for REE has spiked the research initiatives on new potential REE resources in Europe and is also linked to the increasing exploitation efforts from various geological settings. Regarding on that fact, Greece could play an important role in REE market by targeting the potential evaluation of sedimentary formations such as bauxites, phosphorites, placers and laterites. The present study is providing a review based on the distribution and quantification of the REEs in various sedimentary formations of Greece and, specifically, in the black costal sands near Kavala granitoids, the bauxite deposit of Parnassos-Ghiona, the phosphate rocks of Epirus and, finally, the lateritic ores of Evia and Larymna. The uranium (U) and thorium (Th) content of these formations was also extensively investigated because of its close geochemical association with the REEs. In order to contribute to better understanding of the nature of REE and the above-mentioned actinides from micro- to nano-meter scale a number of analytical techniques were applied. In particular, electron microscopic techniques (SEM-EDS, EPMA, TEM/HRTEM) were combined with synchrotron radiation (SR)- methods (μ-XRF and μ-XANES) as well as with single-crystal XRD and ICP-MS/ LA-ICP-MS. The allanite-bearing black coastal sands close to Kavala granitoids (N. Greece) have gained the attention displaying a total REE (ΣREE+Y) content ranging from 4010 to 10810 ppm, while Th was also enhanced (236-1205 ppm). The chemistry of the sand mineral components showed that the main Th- and REE- hosting phases were allanite and titanite and, to a lesser extent, monazite, zircon and apatite (Tzifas 2017 doctoral dissertation, Papadopoulos et al., 2016). In addition, chemical analyses of the magnetic and non-magnetic fractions of the sands exhibited higher Light REE (LREE: La-Gd) concentration in the latter (1908 ppm and 12470 ppm respectively) due to the relatively higher presence of the afore-mentioned REE-bearing minerals. Tzifas et al. (2017) also studied coastal sands of the volcanic island of Nisyros and found relative enrichment in High Field Strength Elements / HFSE (Nb, Ta) compared to actinides (namely U and Th) and REEs. The same authors interpreted this as combination of background geology (provenance) and mineralogical composition of the sands controlling the particular endowment in critical metals. Papadopoulos (2018) extensively studied the REE and actinide content in various coastal areas near granitoids revealing that in Mykonos and Naxos Islands the REE content was also enhanced (ΣREE: 64-9620 ppm and 74-4700 ppm respectively) and comparable with those of the Kavala’ ones. Greek bauxites from the Parnassos-Ghiona active mines studied by Gamaletsos et al. (2019) demonstrated an increased content in LREE (varying from 106 to 913 ppm) compared to the relatively lower content of the HREE (ΣHREE- from Tb to Lu including Y- varying between 45 and 179 ppm; ΣHREE = 95 ppm). The overall REE concentration (ΣREE + Y+Sc) varied from 192 to 1109 ppm. However, it should be pointed out that significant variations were observed between the Fe-depleted (avg. 268 ppm) and the Fe-rich bauxites (avg. 569 ppm). This differentiation of the REE concentration in Fe-rich bauxites can be attributed to the higher participation of (diagenetic and/or epigenetic) REE minerals, mainly LREE-fluorocarbonates as indicated by the SEM-EDS investigation. It is worthy to be mentioned that the REE-content of the Greek bauxite metallurgical residues / BR (also known as “red mud”) seems to be remarkably increased by almost two times compared to that of the Parnassos-Ghiona bauxite parent material. The data presented by Gamaletsos et al. (2019) showed similar REE values compared to karst-type bauxites of the globe. The actinide content, and particularly of Th, is also relatively increased in the bauxites. The Fe-depleted samples contained up to 63 ppm Th whereas the corresponding content of the Fe-rich samples is lower (Gamaletsos et al., 2011; Gamaletsos et al., 2016). Organic-rich phosphatized limestones from Epirus region were found to present enhanced phosphorous content (27 wt.%) and natural uranium enrichment (647 ppm). Their relatively high ΣREE + Y content (56-280 ppm) can be linked, on the basis of the mineralogical and geochemical investigations, with the presence of carbonate-apatites and/or organic matter (Tzifas et al., 2014). The REEs average concentration values were compared to those of phosphate deposits of other countries (i.e., Israel, Egypt, Tunisia) demonstrating that, regardless of the observed similar trends, the Epirus samples were not especially enriched. Nickeliferous laterite ores from two typical central Greece deposits of Larymna and Evia (Samouhos et al., 2019), exhibited ΣREE = 774 ppm and 76 ppm respectively, while their clay fraction demonstrated significant enrichment in contrast to the initial ore (ΣREE = 1014 and 40 ppm respectively). The scandium (Sc) concentrations found to present similar values in both mining areas (64 and 42 ppm, respectively). The mineralogical investigation of laterites indicated that both materials contain crystalline hematite- and chlorite group phyllosilicates, whereas the Evia sample additionally illite. Transmission electron microscopy investigations revealed that laterite ores consisted of complex nanoscale aggregates of the above-mentioned phases.

To the extent that Eu/Eu* - Ce/Ce* bivariate diagrams for sedimentary geomaterials provide information about their origin as Leybourne & Johannesson (2008) suggested, similar diagrams were constructed for the same reason in the case of bauxites, laterites, phosphorites and Kavala black sands. The average values of various geomaterials of the globe were also used for comparison. The black sands showed that the samples are not located close to the field of the average granite as they were influenced from various geological processes. In the case of the bauxites, it is revealed that the Ce/Ce* ratios significantly varies. This fact might be attributed to the Ce3+ ↔ Ce4+ and the LREE re-mobilization during the supergene/epigenetic processes. The lateritic samples exhibited high Eu/Eu* ratios as a matter of the fact that they do not exclusively originate in ultrabasic -ophiolitic- rocks as previously considered, while the organic-rich phosphatized limestones are not typical phosphorites, covering a rather large range as a result of the impact of surface waters.

ABSTRACT. Introduction Coastal sands are a result of weathering of nearby rocks. The erosion and deposition can be a result of either the sea waves, or of the action of the local streams and rivers. Black coastal sands are a result of the action of sea waves that separate the heavy (black) from the light (white) minerals. The heavy fraction of the black sands is mainly consisted of titanite, rutile, monazite, xenotime, zircon, magnetite, illmenite and allanite. Sometimes, the concentration of such minerals allows their economic exploitation either for economic metals or Rare Earth Elements (REE). Some heavy minerals being resistant in chemical weathering are exclusively enriched in REEs, such as monazite, xenotime and allanite. The light fraction is consisted of common minerals like quartz, feldspars, calcite and other minerals found in the nearby rocks (Pohl, 2005; Ridley, 2013). Previous research has been done about the coastal black sands found in Greece. Most of them are focused at northern Greece (Pe and Panagos, 1979; Pergamalis et al., 2001; Papadopoulos et al., 2014; 2015; 2016; 2018; Tzifas et al., 2017). The study area belongs to the Axios Zone. Particularly, in the narrower area metamorphic rocks intruded by felsic igneous rocks and their sedimentary counter parts in the presence of Neogene – Quarternary formations are found (Filippidiset al., 1997 and references there in). Objectives Filippidis et al. (1997) provided a mineralogical and radiological study of the studied sands. In this study, the main objectives are to provide additional mineralogical information. Moreover, the chemical content, exclusively focusing on the REEs is also studied in order to give the economic importance of these sands. The REE concentrations of the studied sands are compared to those of black sands exhibiting elevated REE contents from Kavala and Sithonia (Papadopoulos et al., 2014; 2016). Finally, primary effort to study the source rocks of these sands is attempted by comparing the REE patterns of the black sands with the REE patterns of neighbouring granitic rocks (Fanos and Monopigado). Methods Four samples (5 kg each) collected from a coastal slope at height of five meters above sea level at a distance of 30 meters from each other, in order to examine a horizon of black sand formed in the recent geological period. The samples have been washed with clean water to remove any shells and algae and dried at the oven at 50 degrees for 48 h. The 4, 2, 1, 0.063 mm sieves have been used to obtain the grain size distribution of the samples. For minerals separation, representative 15 – 20 g of the 1 – 0.063 mm of each sample have been selected. Hand magnet was used to remove magnetite. Afterwards, the magnetic (I >1.70 mA) and non-magnetic (I <1.70 mA) fractions have been obtained by using a magnetic separator. 0.5 g from each magnetic fraction was pulverized, in order to get the semi-quantitave mineralogical composition with P-XRD. Then, the sample being the most enriched in zircon (sample AGG-3) was selected for chemical analyses. In particular, the whole rock and the fractions >4, 4-2, 2-1, 1-0.063 mm as well as the magnetic and non-magnetic fractions of 1-0.063 mm grain size have been pulverized and analyzed for their major elements content with XRF and trace elements content by ICP-MS at MS Analytical laboratories, Canada. Results According to Schlee (1973), samples AGG-1, 2, 4 are classified as gravels and sample AGG-3 as gravel sediment, indicating probable fluvial transport and deposition environment (Venetikidis, 2012). The main mineral constituents are quartz, feldspars and phyllo-silicates. Minor quantities of magnetite and titanite have been found. Traces of pyroxenes, amphiboles and dolomite as well as heavy minerals such as zircon, hematite and illmenite are present. The ΣREE (ppm) of the samples was 75.14 for the whole rock (w.r.) and 99.66, 76.00, 54.72 and 73.46 for the fractions >4 mm, 4-2 mm, 2-1 mm and 1-0.063 mm respectively. For the magnetic separated samples,the I>1.70 fraction has 283.95 ppm while the I <1.70 fraction has 39.88 ppm. The whole rock (w.r.) REE patterns, have been compared to the REE patterns of black sands from Kavala and Sithonia, displaying elevated REE concentrations (Papadopoulos et al., 2014; 2016) (Figure 2). In order to assume the source rock, the whole rock REE patterns are compared with those of local granitic rocks (Fanos and Monopigado) (Michail et al., 2016 and references therein and Koroneos, 2009 respectively) (Figure 3). Conclusions Excluding several common silicates, like quartz and feldspars, the main REE bearing minerals are zircon and titanite. The ΣREE content of the studied samples are below but close to the average value of the Sithonia sands, but well below those of Kavala sands. The REE pattern of the w.r. is quite similar to those of Monopigado and Fanos granitoids. The presence of ultrastable detrital non opaque heavy minerals like zircon and titanite along with the unstable amphiboles and pyroxenes andthe stable to moderate stable opaque heavy minerals hematite and ilmenite is suggestive for mineralogical immaturity and thus relatively limited sediment transportation. Furthermore, the absence of the characteristic pinkish feldspars of Fanos pluton, implies that the source rock of the studied sediment could possibly be the Monopidado pluton. Further investigation is imperative, in order to determine the source rock.

References Filippidis, A., Misaelides, P., Clouvas, A., Godelitsas, A., Barbayiannis, N., Anousis, I., 1997. Mineral, chemical and radiological investigation of a black sand at Touzla Cape, near Thessaloniki, Greece. Environmental Geochemistry and Health 19, 83-88. Koroneos, A., 2009. Petrogenesis of the Upper Jurassic Monopigadon pluton related to the Vardar/Axios ophiolites (Macedonia, northern Greece) and its geotectonic significance. Chemie der Erde 70, 221-241. Michail, M., Pipera, K., Koroneos, A., Kilias, A., Ntaflos, T., 2016. New perspectives on the origin and emplacement of the Late Jurassic Fanos granite, associated with an intra-oceanic subduction within the Neotethyan Axios-Vardar Ocean. International Journal of Earth Sciences. Doi 10.1007/s00531-016-1321-4. Papadopoulos, A.,Christofides, G., Koroneos, A., Hauzenberger, C., 2015. U, Th and REE content of heavy minerals from beach sand samples of Sithonia Peninsula (northern Greece). NeuesJahrbuch für Mineralogie – Abhandlungen (Journal of Mineralogy and Geochemistry) 192/2, 107-116. Papadopoulos, A., Christofides, G., Pe-Piper, G., Koroneos, A., Papadopoulou, L., 2014. Geochemistry of beach sands from Sithonia Peninsula (Chalkidiki, Northern Greece). Mineralogy and Petrology.Doi 10.1007/s00710-014-0351-5. Papadopoulos, A.,Koroneos, A., Christofides, G., Papadopoulou, L., 2016. Geochemistry of beach sands from Kavala, Northern Greece. Italian Journal of Geosciences.Doi 10.3301/IJG.2016.01. Pe, G.G., Panagos, A.G., 1979. Heavy mineralogy of river and beach sands, continental Greece.NeuesJahrbuch für Mineralogie 136, 254–261. Pergamalis, F., Karageorgiou, D.E., Koukoulis, A., Katsikis, I., 2001. Mineralogical and chemical composition of sand ore deposits in the seashore zone N. Peramos-L. Eleftheron (N. Greece). Bulletin of Geological Society of Greece XXXIV/3, 845–850. Pohl, W., 2005. Economic Geology: Principles and Practice. Wiley- Blackwell, Chichester, 663 p. Ridley, J., 2013. Ore Deposit Geology. Cambridge University Press, New York, 409 p. Tzifas, I.T., Misaelides, P., Godelitsas, A., Gamaletsos, P.N., Nomikou, P., Karydas, A.G., Kantarelou, V., Papadopoulos, A., 2017. Geochemistry of coastal sands of Eastern Mediterranean: The case of Nisyros volcanic materials. Chemie der Erde. http://dx.doi.org/ 10.1016/j.chemer.2017.07.002. Schlee, J., 1973. Atlantic continental shelf and slope of the United States: sediment texture of the northeastern part. U.S. Geol. Surv., Prof. Pap.529-L, p. 64 Venetikidis, D.A., 2012. Sedimentary and petrologic study of Quaternary clastic sediments of Mygdonia basin at Platanorema site, Lagkadikia. MSc Thesis 92 p.

ABSTRACT. The Rare Earth Elements (REEs) have recently moved into the spotlight since the European Commission were characterized them as critical elements. The wide use of REEs in a variety of modern applications set in motion many exploration projects for new potential REE-bearing resources. In Greece, also there are prominent locations which demonstrate REE enrichments giving the opportunity for further research. In the frame of the current research work, REE-bearing minerals where found to be present within the Phyllite-Quartzite Series of SE Alagonia Area (Peloponnese). The study area extends to the south-eastward parts of Alagonia village, in the NW slopes of the Taygetos Mt., and geologically, consists of metamorphic nappe pile that took place during the plastic deformation of the Phyllitic-Quartzitic series and its thrusting westward on the top of the Plattenkalk series in Miocene times (Xypolias & Doutsos 2000; Jolivet et al., 2010). Furthermore, the Phyllite–Quartzite series dominated by schists and metapelites, and a lower unit of the Plattenkalk series consisting of multi-colored crystalline platy Mesozoic limestone topped by meta-flyschoidal sequence of the lower Oligocene. Due to the intercontinental subduction events in Oligocene times, both the Plattenkalk series, as the deeper metamorphic unit of the external Hellenides, and the Phyllite–Quartzite series, underwent successively HP/LT metamorphic episodes, the former during late Oligocene-lower Miocene times (Thee & Seidel 1991), and the latter in Lower Miocene 19-24 My (Panagos et al., 1979; Seidel et al., 1982, 2006).

ABSTRACT. Introduction The Aegean area was part of the Hellenic orogenic system throughout the early Tertiary with continuous landmasses between mainland Greece and Western Anatolia. This continental status, known by Philippson as “Agaeis” (Philippson, 1901), lasted until the late Miocene, when mammal migrations of the ‘Pikermi’ fauna (Hipparion as characteristic fossil) occurred. At this period, the last Tethyan oceanic remnant of the Ionian Basin entered the Hellenic subduction zone and resulted in the acceleration of the African plate subduction (from 1 to 5 cm/year) and created the individualization of the Aegean microplate, south of the North Aegean Basin (e.g., Royden and Papanikolaou, 2011). The above geodynamic change gradually produced a thinning of the Aegean continental crust causing subsidence, which became more extensive during the Quaternary. Data based on lithoseismic profiles in the North Aegean (Skyros Basin) indicate that towards the Skyros and Limnos Platform there is no sedimentary cover or a very thin cover (e.g of several tens of meters) resting on top of the Alpine basement. According to published sedimentation rates obtained from coring, the older sediments might extend back to 400-500 Ka in extended areas of the Central - North Aegean Sea (Papanikolaou et al., 2019). The availability of high resolution bathymetric and seismic reflection data revealed that several of North Aegean islands would be connected by stretches of land allowing terrestrial animals to travel between them. The existence of such land passages would have affected connectivity and thus biodiversity and colonization rhythms. The overall aim of this study is to provide a synthesis of the Νorth Aegean palaeogeography during the Pleistocene and examine its role as a southeastern entrance to hominin movements out of Asia and into Europe and subsequent occupations and migrations. State-of-the art New high resolution bathymetric and seismic reflection data, bolstered with tectonic data on active faults have enriched our understanding of the palaeogeography of the North Aegean. Regional subsidence rates at the Aegean margins during the last 400 Ka have been investigated using high-resolution seismic reflection profiles, indicating a gradual process, based on successive glacial sea-level lowstand systems of Marine Isotope Stages (MIS) 2, 6, 8, 10 and probably 12 (Lykousis, 2009). Higher subsidence rates were calculated for MIS 12–8 at the North Aegean margins (1.46–1.88 m/Ka) whereas sedimentological and mineralogical analyses in commercial boreholes in the northern Aegean revealed sediment deposition under riverine-lake conditions throughout the Pliocene and the Early Pleistocene. In world prehistory, the questions of geography and process of the first penetrations to Europe by late Early Pleistocene hominins and later colonization by Middle Pleistocene hominins remain wide open. In Iberia, several pre-1 Ma and post-1 Ma archaeological sites indicate a very early presence of hominin groups. By comparison, the very sparse and contested Balkan archaeological record from the same periods meant that, until recently, the role of the Balkan Peninsula as a gateway to Europe has been unclear. The question became all the more pressing by the discovery a Homo erectus skull near Kocabaş in the province of Denizli, Aegean Turkey, dating to around 1.1 Ma. Results and Discussion More recently, archaeological work at Rodafnidia, Lisvori, near the Gulf of Kalloni on the island of Lesbos, ~300 km to the west of Kocabaş, returned absolute dates and evidence of Middle Pleistocene hominin activity from ~500 ka (Galanidou et al., 2013). The archaeological variability has indicated repeated hominin occupations on Lesbos over long periods of time from at least the early stages of the Middle Pleistocene. The stone tools from the site belong to the Acheulean and have close industrial affinities with material excavated at Gesher Benet Y’aaqov on the bank of the Jordan River in northern Israel, which dates to 800 Ka and the lower strata at Kaletepe Deresi 3 on a seasonal drainage in the Göllüdağ area near Cappadocia. The verterbrate palaeontology of Lesbos (Villanfrancian fauna) suggests that animal crossings from Anatolia to the Aegean began much earlier. Two possible, though not mutually exclusive, routes for early hominin dispersals from Anatolia to Europe therefore emerge: through the, inadequately explored, northern Balkan territories, or through a southern route in the North Aegean. Thus, the extensive submerged landscapes of the Aegean hold clues to understanding the early Pleistocene hominin expansions 'Οut of Asia' into Europe. A second issue concerns the situation after the submergence of the N. Aegean, when migrations depended on land connections exposed during glacial sea-level lowstands. These coastal landscapes may have provided relatively fertile and productive refugia for plants, land mammals and hominins. The Palaeolithic sites discovered in the last 20 years on the islands of Crete, Thasos, Limnos, the Inner Ionian Archipelago and Lesbos suggest that land-bridge crossings become more frequent in the late Middle and Late Pleistocene, as glacial lowstands reached ~120 m below present.

Fig.1 Bathymetric map of the North Aegean area showing the areas: 0-120 m depth, where the paleocoastline was located 20 Ka ago during MIS 2, 120-400 m depth, where palinspastic tectonics show the existence of land bridges during MIS 4, 6 and 8, and depths more than 400 m, where palinspastic tectonics show the existence of marine basins.

Some answers related to the questions on the evidence for land bridges during glacial sea-level lowstands of the late Middle and Late Pleistocene and their importance for human migrations may be obtained from the study of the North Aegean Sea and especially of the Northern Sporades - Limnos platform, which might serve as a major land bridge from Northwestern Anatolia to southeast Thessaly (Fig. 1, area A). Here the maximum depth is about 350 m, between the islands of Aghios Efstratios and Kyra Panagia - Youra. Another probable land bridge might have been south of the Skyros Basin, between Lesbos and Skyros – Evia, where the maximum depth is around 250m (Fig. 1, area B). The study of the active faults surrounding this area of the two North Aegean platforms has shown that the fault throws are several hundred m or even more than 1.0 –1.5 km. Especially in the case of area B the NW-SE faults forming a graben structure with fault lengths more than 8–11 km east of Skyros Island have probably caused the tectonic subsidence of the platform to 250 m depth. Taking into account the available chronological data in combination with the available sedimentation rates we may conclude that several active faults have been activated during the last 200–400 Ka, with slip rates ranging around 3mm/yr. Thus, the presently maximum depths within the North Aegean platforms did not exist during the previous lowstands in MIS 4, 6 and 8. In conclusion, land bridges between the western coastlines of Minor Asia and the eastern coastlines of continental Greece probably existed during the lowstands of MIS 4, 6 and 8, due to the regional subsidence combined with the tectonic subsidence caused by the normal/oblique faulting especially of the NW-SE trending faults within the platform areas (Papanikolaou et al., 2019). Thus, hominin migrations were possible through the North Aegean until the late most Middle Pleistocene around 140 Ka. References Philippson, A., 1901. Beitrage zur Morphologie Griechenlands. Geogr. Abh. 3, 1-96. Galanidou, N., Cole, J., Iliopoulos, G., McNabb, J. 2013. East meets west: the Middle Pleistocene site of Rodafnidia on Lesvos, Greece. Antiquity 87(336). Lykousis, V., 2009. Sea-level changes and shelf break prograding sequences during the last 400ka in the Aegean margins: subsidence rates and palaeogeographic implications. Continental Shelf Research 29(16), 2037-2044. Royden, L.H., Papanikolaou, D.J., 2011. Slab segmentation and late Cenozoic disruption of the Hellenic arc. Geochem. Geophys. Geosyst. 12, Q03010, doi: 10.1029/2010GC003280. Papanikolaou, D., Nomikou, P., Papanikolaou, I., Lampridou D., Rousakis, G., Alexandri, M., 2019. Active Tectonics and Seismic Hazard in Skyros Basin, North Aegean Sea, Greece. Marine Geology 407, 94–110.

ABSTRACT. The International Ocean Discovery Program Expedition 381: Corinth Active Rift Development was conducted in late 2017 (offshore phase-drilling campaign) and early 2018 (onshore phase-Bremen Core Repository). The primary objectives of the Expedition 381 were to target the active continental Corinth Rift (Greece) in order to: a) obtain high spatial and temporal resolution records of the rifting process dynamics, b) to study the interaction of climate and tectonics on sedimentary and surface processes in a rift zone, c) to improve regional hazard assessments in one of the most seismically active regions of Europe and d) to generate a new high resolution record of Quaternary paleoclimate and paleoenvironment evolution from a semi-isolated basin dominated at present by typical Mediterranean ecosystems. During IODP Exp. 381, three sites (Figure 1) located along the Gulf of Corinth, were drilled and logged, sampling in high resolution the syn-rift sedimentary sequence back to ~1.5 Ma or more (Shillington et al., 2019; McNeill et al., 2019a). Preliminary results produced during the onshore phase of the expedition confirmed that the retrieved deposits contain a rich and complex record of the tectonics, climate and palaeoenvironment interplay in the syn-rift basin. The connection of the Gulf of Corinth to the Mediterranean is controlled by basin sills resulting in alternating aquatic conditions. These vary between open ocean/marine and isolated phases as sea level fluctuates in response to climate forcing (glacial-interglacial cycles). As a result, a unique range of paleoenvironmental gradients is encountered across the central (M0078 and M0079) and eastern (M0080) rift impacting depositional processes, sediment and water chemistry and composition of microfossil assemblages such as calcareous nannofossils, foraminifera, diatoms and dinoflagellate cysts (Shillington et al., 2019; McNeill et al., 2019a), while pollen assemblages from the same intervals record alternating periods of forest or herb vegetation in the borderlands of the Gulf of Corinth. During interglacial periods, when the sea level was high, the Gulf was connected to the global ocean and marine microfossil assemblages including foraminifera, diatoms, calcareous nannoplankton, and dinoflagellate cysts were observed. High abundances of foraminifera were recorded, while benthic foraminifer abundance was generally higher than that of planktonic foraminifers. The dominant planktonic foraminifera species (neogloboquadrinids and T. quinqueloba) suggest high fertility in surface waters. High abundances of buliminids and bolivinids in the benthic assemblages suggest increased organic fluxes to the seafloor. During isolated/semi-isolated periods, when the Gulf appears to have been fully or partially cut off from the global ocean complex aquatic microfossil assemblages, mainly constituted by non-marine diatoms and organic dinoflagellate cysts, suggest brackish paleoenvironmental conditions. Foraminifers tend to be absent or in low abundances, although brief intervals with higher foraminifer abundance were also observed. The transitions between the marine and isolated/semi-isolated intervals expressed in the micropaleontological and sedimentary record are particularly complex and varied in their length and character. Preliminary pollen and terrestrial non-pollen palynomorph (NPP) assemblages analyzed during the onshore phase of the expedition allow to establish a direct link between the response of terrestrial and aquatic environments (Mc Neill et al., 2019b; Shillington et al., 2019). The Arboreal/Non Arboreal Pollen ratio (AP/NAP) fluctuates at orbital scale suggesting the alternation of forested and open landscapes in the borderlands of the Gulf of Corinth. The first palynological results point to increased AP percentages during marine intervals (interglacials), however, further analyses and a higher temporal resolution are required to understand the vegetation response at orbital and sub-orbital time scales. Quercus dominates the deciduous trees percentages, but other mesophilous trees such as Corylus, Ulmus, Carpinus, Tilia, and Acer are also encountered. Cedrus appears to be the dominant conifer tree in the older part of the sequence, while Abies in the upper. Relict pollen taxa (e.g. Carya, Pterocarya, and Liquidambar) were also encountered in the sequence. Steppic elements (e.g., Artemisia and Ephedra) are more abundant during isolated/semi-isolated intervals (glacials) and suggest the occurrence of a rather open landscape. Mediterranean sclerophyllous vegetation increases towards the top of the sequence, depicting the significant role of Mediterranean maquis in the modern vegetation surrounding the Gulf of Corinth. Combined multiproxy results produced during the onshore phase showed the existence of significant variations in sedimentation rates in the Corinth Gulf basin between glacial and interglacial periods. These findings confirm the dominant role of Quaternary climate forcing and eustatic sea level fluctuations in shaping the paleoenvironment in the Corinth Gulf basin. Analyses of M0079 sediments revealed that during glacial periods sedimentation rates were 2 to 7 times higher than during interglacial periods (McNeill et al., 2019b). Higher sedimentation rates during glacials are most likely associated with increased erosion and runoff driven by the decrease and change of vegetation cover during the glacial, also observed in other existing long Mediterranean palaeovegetation records (Sadori et al., 2016; Tzedakis et al., 2006). This new high-resolution palaeoenvironmental and palaeoclimatic sedimentary record can provide new insights to the the long-term vegetation dynamics in response to glacial/interglacial cycles during the last ~1Ma. Situated at a key location at the southernmost tip of the Balkan Peninsula, the Corinth Rift deposits have the potential to be an invaluable palaeo-archive that will improve our understanding concerning the the evolution of marine and terrestrial ecosystems in the Mediterranean and allow to infer lead and lag relationships between the land and sea ecosystem response.

ABSTRACT. The sedimentary and fossil record of Chios island (eastern Aegean sea) holds key evidence to understand the geodynamic and paleogeographic evolution of the Eastern Mediterranean area, as well as all the complex geological events that led to the closure of the Palaeotethys ocean and subsequent opening of Neotethys in the south. Two tectonostratigraphic units are distinguished since the synthesis of Besenecker et al. (1968) on the geology of the island. The Lower (relative autochthonous) Unit is made of siliciclastic turbidites, which contain olistolithes of various lithologies, ranging in age between the Silurian and the Carboniferous; they are overlain by a Mesozoic carbonate sequence. The Upper, allochthonous Unit is thrust over the Lower Unit and is only preserved in a number of isolated klippes. It is composed of Upper Carboniferous turbidites, Lower Permian sandy/marly limestones and Middle Permian shallow-water carbonates, which are overlain by red siltstones and Jurassic platform carbonates. According to Zanchi et al. (2003), the Upper Palaeozoic sequence of the Lower Unit is of Laurasian affinity, while Angiolini et al. (2005) suggested a Gondwanan affinity for the Upper Unit, based on the Brachiopods found in the Middle Permian limestones. We here provide for the first time evidence of the presence of Upper Permian shallow water carbonates within the Upper Unit, in which the identified foraminiferan record is also suggestive of North-Gondwanan affinity.

Studied material Three nearly 3m-thick sections of Permian limestones and marls of the Upper Unit were observed and sampled along the east coast of the Marmaro Bay, situated in the north-eastern part of the Chios island (Kardamyla, N 38°32'29.76", E 26° 7'5.67"). The access to the area is easy by car as a settlement has been developed. The total length of the outcrop is 283 m and it is interrupted by several small faults and landslides.

Results The three studied sections may be assigned to the latest Capitanian/earliest Wuchiapingian, latest substage of the Middle Permian (= Guadalupian) and/or oldest stage of the Late Permian (= Lopingian). Two of them are characterized by abundant gymnocodiacean algae, which are associated with some rare smaller foraminifers, miliolates, nankinellins and nodosariates. The well-characterized Capitanian/Wuchiapingian strata display interesting bioaccumulated perireefal microfacies with richthofeniid brachiopods and inozoan calcisponges. They are biostratigraphically characterized by an assemblage of Reichelina cf. media, Dunbarula? sp., Altineria alpinotaurica, Labioglobivalvulina, Frondina and Robuloides. Other perireefal microfacies show abundant elements of a new tubiphytid genus and species.

Discussion and conclusions The palaeogeographical distribution of Altineria alpinotaurica includes now Chios, the Taurus mountains in Turkey, the NW and central Iran, whereas primitive forms of the genus are also known from Tunisia and Armenia. All these areas were part of the Perigondwanan border during the Wuchiapingian, which would suggest that the opening of the Neo-Tethys did not begin prior to the Changshingian (= latest Permian).

ABSTRACT. Introduction The geological structure of Limnos Island comprises a clastic sedimentary sequence of Oligocene age with extensive volcanic rocks of Lower Miocene age (Innocenti et al., 1994, 2009). The available geological maps (Roussos, 1994; Innocenti et al., 2009) do not comprise a stratigraphic subdivision with distinct stratigraphic formations but a description of the dominant lithology. The available stratigraphic and sedimentological studies (e.g., Caracciolo et al., 2011; Maravelis and Zelilidis, 2012; Kostopoulou et al., 2018) do not present a coherent tectono-stratigraphic structure of the island and their conclusions are referring to an Upper Eocene - Oligocene stratigraphic range with a total thickness of less than 800 m. Our research comprised geological mapping, combined with several stratigraphic sections from the lower to the upper horizons and tectonic analysis combined with calcareous nannofossil biostratigraphy (Martini, 1971; Agnini et al., 2014). Results Our results have shown that: 1) Limnos volcano-sedimentary sequence exceeds 2200 m of thickness and 2) the stratigraphic range extends from the Late Eocene (nannofossil biozone NP17, around 38–40 Ma) to the Oligocene/Miocene boundary (nannofossil biozone NP25 around 24–25 Ma and up to 23 Ma within biozone NN1). Characteristic stratigraphic assemblages are: - The lower horizons, cropping out in Southeast Limnos at Bay Agias, are more than 300 m thick and their age is of Late Eocene (NP17), comprising a nannofossil assemblage of Helicosphaera compacta, Sphenolithus predistentus, S. spiniger and S. obtusus. - An overlying distinct horizon, cropping out along the crest of the NW-SE trending hill of Southeast Limnos east of Fissini, consists of a blocky formation with olistolites of Nummulitic neritic limestones. This horizon occurs about 100–120 m above the lowermost rhythmic alternations of turbiditic sandstones and pelites belonging to the Late Eocene (nannofossil biozone NP17) with H. compacta, S. obtusus, Dictyococcites bisectus and Reticulofenestra umbilicus. - Another distinct horizon about 150–200 m higher than the blocky formation consists of several interlayering volcanic tuffs within a cyclical sedimentary sequence exposed at Cape Ag. Eirini. It has been dated as Late Eocene-Early Oligocene up to biozone NP23 determined from the presence of Sphenolithus predistentus and S. distentus (27.14–30.0 Ma). Radiochronological data from the lower volcanic intercalations have revealed an age of ~36 Ma (Maravelis et al., 2016). - Several hundred meters upward in the sequence there is a change to thick sandstones-conglomerates of variable thickness, depending on the position of the area within the lobes of submarine fans. An average thickness of the conglomerates at the central part of Eastern Limnos is 150–200 m. Its age has been determined as Late Oligocene (27.14–26.81 Ma, biozone NP24), based on the contemporaneous presence of Sphenolithus ciperoensis and S. distentus. The stratigraphic sequence continues into the Late Oligocene until the Oligocene/Miocene boundary, with a characteristic N-S section along the western part of Limnos, without important tectonic breaks, from Kaspakas to the northwestern cape of Mourtzouflos at the area of Vigla. The younger ages have been determined at this northwestern part of Limnos with characteristic assemblages of NP25 in between 26.81–24.36 Ma, such as S. ciperoensis and D. bisectus and even up to 23 Ma (biozone NN1) based on the presence of Sphenolithus delphix. Impressive volcanic dikes and lava flows become frequent towards the upper horizons. However, the most extensive volcanic extrusions occur at the central-southern part of Limnos and they are dated as Early Miocene (18–22 Ma; Pe-Piper and Piper, 2002). Thick pyroclastic deposits cover unconformably the previous sedimentary sequence in central Limnos, producing characteristic morphological cliffs due to their erosional style. The overall stratigraphic sequence of Limnos together with its equivalent sequence of Thrace shows a molassic type deep marine environment within a back-arc basin (Papanikolaou, 1993, 2013) as this is shown: 1) by the unconformable deposition of the Paleogene clastic sediments on a varietated Alpine basement, belonging either to the Circum Rhodope belt along its northern margin, deformed during the Late Jurassic with deposition of unconformable neritic limestones in Early Cretaceous (Aliki Limestones, west of Alexandroupolis), or to the Eastern Greece unit of the Internal Hellenides along the southern margin, deformed in Early Eocene, 2) by the co-existence of the volcanic arc within this North Aegean - Thrace Basin. In fact, flysch type deposits during this period of Late Eocene - Oligocene occur at the fore-arc basins of the External Hellenides fold and thrust belt (e.g. Tripolis, Ionian etc.).

Correlations with the Thrace Basin The above stratigraphic sequence of Limnos can be correlated with the stratigraphy of the similar sequences around Alexandroupolis in the Western Thrace basin (Papanikolaou and Triantaphyllou, 2010). The Limnos sequence can be correlated with the upper Group of the Pylaea formation, whereas the Lower group of the Kirki formation is not cropping out on Limnos, but it could occur deeper. The characteristic formation of the Upper Eocene Avantas neritic limestones, separating the two clastic sequences in Alexandroupolis can be correlated with the olistolite horizon of Southeast Limnos, where the same neritic limestones occur as blocks, slided within a deep basin. Generally, the sedimentary facies of the Limnos clastic sequence corresponds to a much deeper setting than that of the Alexandroupolis area. Volcanism is also present in Alexandroupolis in the Upper Eocene-Oligocene Kirki sequence (related also to the metalliferous deposits of Kirki) but also in the higher horizons of the Oligocene Pylaea sequence with volcanic extrusions also in the Early Miocene. The Lower Miocene volcanic breccia of Limnos, unconformably overlying the Limnos clastic sequence, can be correlated to the Aghios Efstratios pyroclastic sequence as well as to the pyroclastic sequences of Northern Lesbos Island. References Agnini, C., Fornaciari, E., Raffi, I., Catanzariti, R., Pälike, H., Backman, J., Rio, D., 2014. Biozonation and biochronology of Paleogene calcareous nannofossils from low and middle latitudes. Newsletters on Stratigraphy 47/2, 131–181. Caracciolo, L., Critelli, S., Innocenti, F., Kolios, N., Manetti, P., 2011. Unraveling provenance from Eocene–Miocene sandstones of the Thrace Basin, NE Greece. Sedimentology 58, 1988–2011. Innocenti, F., Manetti, P., Mazzuoli, R., Pertusati, P., Fytikas, M., Kolios, N., 1994. The geology and geodynamic significance of the Island of Limnos, North Aegean Sea, Greece. N. Jb. Geol. Palaont. Mh. 11, 661–691. Innocenti, F., Manetti, P., Mazzuoli, R., Pertusati, P., Fytikas, M., Kolios, N., Vougioukalakis, G.E., Androulakakis, N., Critelli, S., Caracciolo, L., 2009. Geological map (scale 1:50,000) of Limnos island (Greece): explanatory notes. Acta Vulcanol. 20, 87–97. Kostopoulou, S., Maravelis, A.G., Zelilidis, A., 2018. Biostratigraphic analysis across the Eocene–Oligocene boundary in the southern Hellenic Thrace basin (Lemnos Island, north Aegean Sea). Turkish J. Earth Sci. 27, 232–248. Maravelis, A.G., Boutelier, D., Catuneanu, O., Seymour, KSt., Zelilidis, A., 2016. A review of tectonics and sedimentation in a forearc setting: Hellenic Thrace Basin, north Aegean Sea and northern Greece. Tectonophysics 674, 1–19. Maravelis, A., Zelilidis, A., 2012. Paleoclimatology and Paleoecology across the Eocene/Oligocene boundary, Thrace Basin, Northeast Aegean Sea, Greece. Palaeogeogr. Palaeoclimatol. Palaeoecol. 365–366, 81–98. Martini, E., 1971. Standard Tertiary and Quaternary calcareous nannoplankton zonation. In: Farinacci, A. (Ed.), Proceedings 2nd International Conference Planktonic Microfossils Roma: Rome (Ed. Tecnosci.) 2, 739–785. Papanikolaou, D. 1993. Geotectonic evolution of the Aegean. Bull. Geol. Soc. Greece 28, 33-48. Papanikolaou, D. 2013. Tectono-stratigraphic models of the Alpine terranes and subduction history of the Hellenides. Tectonophysics 595-596, 1-24. Papanikolaou D., Triantaphyllou M., 2010. Tectonostratigraphic observations in the western Thrace Basin in Greece and correlations with the eastern part in Turkey. XIX Congress of the Carpathian Balkan Geological Association. Thessaloniki, Greece, 23-26 September 2010, Geologica Balcanica 39 1-2, 293–294. Pe-Piper, G., Piper, D.J.W., 2002. The Igneous Rocks of Greece. The Anatomy of an Orogen. Gebrüder Borntraeger, Berlin. Roussos, N., 1993. Geological Map of Limnos Island, Scale 1.50,000, Athens, IGME.

ABSTRACT. The Ionian islands are situated on the west portion of the Hellenic Arc, part of the most active plate margins in the Mediterranean. The westerly-verging Hellenides fold-and-thrust belt in this area comprises the deformed Meso-Cenozoic basinal succession of the Ionian Zone, which thrusts over the time equivalent slope unit of the Preapulian Zone.The basal front of this tectonic contact outcrops along the eastern edges of Κefalonia and Zakynthos (Zante) islands. The palaeoenvironmental transition between the Late Cretaceous persistent carbonate platform ‘Apulian’ facies and the time-equivalent ‘Pre-Apulian’ facies is very close to the westernmost edge of the islands of Zakynthos (Zante) and Cephalonia (c.f., Bosellini, 2002; Karakitsios, 2013); however these islands are thought to be composed almost entirely of Pre-Apulian facies (with Ionian facies confined to the easternmost fringes of the island, in the hangingwall of the main overthrust. We carried out a geological _fieldwork in the islands of Zakynthos in 2012 and Cephalonia in 2015, with the aim to describe a rarely described near-continuous distal-to-proximal transition from a pelagic slope (eastwards) to a neritic platform (west). Our work focuses predominantly (albeit not exclusively) on the Cretaceous sections, with nannoflora analyses conducted for the first time. Also, Cretaceous microfacies are investigated to interpret the changes of palaeoenvironments from platform margin to distal slope. Stratigraphic sections were logged on the field, and a total of 267 samples were collected along 6 east-to-west transects for successive biostratigraphic analyses: 95 samples in Zakynthos and 172 samples in Cephalonia. This study shows thin-bedded, ‘platform slope’ formations to the east of Zakynthos (Campanian-Maastrichtian), and thicker bedded, carbonate platform-like calcareous formations westwards (usually ?Cenomanian-Turonian). A paleoenvironmental transition between the two facies was recognized, with a gradual general increase of proximality and ‘platform influence’ in slope facies towards the west (Fig. 1). The presence of gradually older rocks towards the east is explained by the consistent westerly monoclinal dip of the outcropping strata; a potential hiatus is present between the Campanian-Maastrichtian and the ?Cenomanian-Turonian packages. Presence of gradually shallower-marine and more proximal palaeo-facies towards the west are explained by the close vicinity of the edge of the Apulia platform. Accordi et al. (2014) argue that southern Zakynthos in the Late Cretaceous was characterized by a toe-of-slope sequence. Our analyses of the Agalas sectionn (southern Zakynthos), however, point out to a more proximal depositional setting, becoming increasingly shallower to the west, where we recognized potential occurrences of in-situ neritic carbonates. In Cephalonia similar palaeoenvironmental trends were also identified, with even clearer outcrops of inner carbonate platform facies identified to the west of the island, around Argostoli (hereby named “Argostoli Platform”). This is characterized by evidence of inner carbonate platform facies, including peritidal cycles and development of redded palaeosol layers encased between thick-bedded or massive fine-grained carbonate units. Arguably, the Argostoli Platform represents the easternmost edge of the Apulian platform, and these facies belong to the Apulian facies domain rather than to the transitional Preapulian ones. Elsewhere in Cephalonia, similar to Zakynthos, from west to east there is a transition between very proximal slope facies dominated by massive megabreccias with neritic clasts and distal slope to basinal facies on the eastern coast of the island (e.g., Agia Efimia location) The biostratigraphic and microfacies analyses are still ongoing for the Cephalonia samples. The final aim of this study is to reconstruct the position of the Apulian platform edge in western Greece, which may have significant implications in oil exploration.

References

Accordi et al, 2014. Microfacies analysis of deep-water breccia clasts:a tool for interpreting shallow v.s. deep-ramp Palaeogene sedimentation in Cephalonia and Zakynthos (Ionian Islands, Greece). Facies, Vol.60, Issue 2, 445 – 466 Bosellini, A., 2002. Dinosaurs ‘‘re-write’’ the geodynamics of the eastern Mediterranean and the paleogeography of the Apulia Platform. Earth-Science Reviews, 59, 211– 234 Danelian, T., Tsikos, H., et al., 2004. Global and regional palaeoceanographic changes as recorded in the mid-Cretaceous (Aptian–Albian) sequence of the Ionian zone (NW Greece). Journal of the Geological Society, London, 161, 703–709 Etiope, G., Papatheodorou, G., et al., 2006. Methane and hydrogen sulfide seepage in the northwest Peloponnesus petroliferous basin (Greece): Origin and geohazard. AAPG Bulletin, 90, no. 5, 701–713 Karakitsios, V., 2003. Evolution and Petroleum Potential of the Ionian Basin (Northwest Greece). AAPG Search and Discovery Article #90017©2003 AAPG International Conference, Barcelona, Spain, September 21-24, 2003 Karakitsios, V., and Rigakis, N., 2007. Evolution and Petroleum potential of Western Greece. Journal of Petroleum Geology, 30 (3), 197 – 218 Karakitsios, V., Triantaphyllou, M. et al., 2010. Preliminary study of the slump structures of the Early Oligocene sediments of the Pre – Apullian zone (Antipaxos island, North Western Greece). Bulletin of the Geological society of Greece, Proceedings of the 12th International Conference Patras, 2010 Karakitsios, V., 2013. Western Greece and Ionian Sea – conventional and unconventional hydrocarbon potential. Presentation

ABSTRACT. Introduction Karnezeika is a Villafranchian locality, situated in the northern part of southern Argolis. No proper excavations have been conducted in the locality. Geologically, the fossils are enclosed in fine-grained red sediments, which filled a small doline in a late Triassic – early Jurassic limestone. The locality of Karnezeika has been discovered in 2005 and the collected material has been stored in both Athens Museum of Palaeontology and Geology (AMPG) and the Laboratory of Palaeontology and Stratigraphy, Department of Geology, University of Patras. The material housed at the University of Patras was studied in the contexts of an Undergraduate dissertation (Kokotini, 2018). The present study is a combined effort from both Institutes to resume the up to now results on the prepared material. Results Despite the fragmentary nature and the scarcity of the material, the biodiversity of the site seems to be significantly high, including at least 22 genera, belonging to 17 families. The preliminary faunal list is provided on Table 1.

Table 1. Preliminary faunal list of Karnezeika Class Reptilia Order Testudines indet. Order Squamata Clade Lacertoidea indet. Clade Ophidia indet. Class Aves Order Accipitriformes Family Accipitridae Order Passeriformes Family Corvidae Pyrrhocorax sp. Class Mammalia Order Artiodactyla Family Bovidae Gazella borbonica Gazellospira torticornis Gallogoral meneghinii Pliotragus sp. Family Cervidae Eucladoceros sp. Order Primates Family Cercopithecidae Papionini indet. Order Carnivora Family Canidae Vulpes sp. Canis sp. Family Felidae Panthera gombaszoegensis Family Hyaenidae Pachycrocuta brevirostris Order Perissodactyla Family Rhinocerotidae Stephanorhinus sp. Family Equidae Equus sp. Order Rodentia Family Arvicolidae Kislangia sp. Kalymnomys sp. Family Muridae Apodemus cf. dominans Family Gliridae indet. Order Lagomorpha Family Leporidae Hypolagus sp.

The majority of the identified taxa indicate an age approximately at the border between middle to late Villafranchian (Kostopoulos, 1996; Rook & Martínez-Navarro, 2010; Koufos, 2014; Doukas & Papayianni, 2016; Koufos & Kostopoulos, 2016). The coexistence of mammalian carnivores and herbivores of varying size, micromammals, birds and reptiles offers a great opportunity to study the Villafranchian faunas of Greece in more detail. Another interesting finding is the presence of a proximal radius, belonging to one of the macaque-like species occurring in this period.

Conclusions The studied locality preserves high interest because of the following: • It is the most comprehensively studied Villafranchian locality in southern Greece, offering new insights on biochronology and biogeography • It comprises a rich fauna including macro-mammals, micro-mammals, birds and reptiles • It is the first locality in Greece with remains of Hypolagus • It includes some rare taxa such as Eucladoceros, Gallogoral, Pliotragus and the papionin primate • In contrast to other Villafranchian localities it includes very few equid remains Τhe study of the bulk of the material which is still unprepared will certainly provide further and more complete data on the Villafranchian of Karnezeika. Thus, more precise conclusions will be made concerning the palaeoecology of the locality and its relationship with other Villafranchian sites in Greece.

Acknowledgements We would like to thank Christos Rigas who first discovered the fossiliferous site and was responsible for the first collection of the material housed at AMPG and the owner of the quarry, Thanasis Iliopoulos, for extracting a large portion of the bone assemblage and maintaining it in the quarry, as well as Dimitrios Kostopoulos and Nikolai Spassov for their useful comments, concerning taxonomic identifications.

Literature Athanassiou, A., 1998. Contribution to the Study of the Fossil Mammals of Thessaly, Faculty of Geology. Ph.D. Thesis, National and Kapodistrian University of Athens, Athens, 354 p. Doukas, C., Papayianni, K., 2016. Small mammals in the Plio/Pleistocene sediments of Greece, in: Harvati, K., Roksandic, M. (Eds.), Palaeoanthropology of the Balkans and Anatolia: Human evolution and its context, 291-302. Kokotini, M., 2018. Osteological study of Pleistocene Mammals from the locality Karnezeika, S. Argolis, Department of Geology, Bachelor Thesis, University of Patras, Patras, 60 p. Kostopoulos, D., 1996. The Plio-Pleistocene Artiodactyls of Macedonia (Greece): Systematic-Palaeoecology-Biochronology-Biostratigraphy. School of Geology, Ph.D. Thesis, Aristotle University of Thessaloniki, Thessaloniki, 612 p. Koufos, G., 2014. The Villafranchian carnivoran guild of Greece: implications for the fauna, biochronology and paleoecology. Integrative Zoology 9, 444-460. Koufos, G., Kostopoulos, D., 2016. The Plio-Pleistocene large mammal record of Greece: Implications for early human dispersals into Europe, in: Harvati, K., Roksandic, M. (Eds.), Palaeoanthropology of the Balkans and Anatolia: Human evolution and its context, 269-280. Rook, L., Martínez-Navarro, B., 2010. Villafranchian: The long story of a Plio-Pleistocene European large mammal biochronologic unit. Quaternary International 219(1-2), 134-144.

ABSTRACT. The fossiliferous sites of Kerassia are located in northern Euboea, Greece. The first excavation was conducted in 1982 by H. de Bruijn, A. van der Meulen (University of Utrecht) and C. Doukas (National and Kapodistrian University of Athens; NKUA). They were not continued until 1992, when G. Theodorou (NKUA) began a series of recurring systematic excavations in the area, revealing seven fossiliferous sites, which can be allocated into two distinct stratigraphical horizons (Iliopoulos, 2003; Theodorou et al., 2003). The lower horizon contains the sites K2, K3, K4 and K5. The upper horizon comprises the sites K1, K6, as well as the site Ke of the initial excavation of 1982. In the present study, the majority of the material from Kerassia, which is housed in the collections of the Museum of Palaeontology and Geology of the NKUA, has been evaluated, shedding light on the faunal composition of the two fossiliferous horizons (Fig. 1), and updating the taxonomic identifications based on a greater sample of specimens (Kampouridis & Dimakopoulos, 2018). The bovid material consists mostly of fragmentary mandibles, whereas crania and horns are rare, making their identification quite difficult. Currently, two main groups can be distinguished: one of a large-sized bovid, resembling the species Tragoportax amalthea, and one of a smaller-sized, resembling Gazella capricornis. It seems that in the lower horizon the bigger bovid is the dominant taxon, while in the upper horizon the smaller one is more frequent. In the upper horizon, a partially preserved skull differs from the rest of the G. cf. capricornis material and resembles Gazella deperdita. In the lower horizon two more bovid taxa can be preliminary referred, ?Palaeoreas lindermayeri and ?Protragelaphus skouzesi. The hipparionine horses are well-represented in Kerassia. However, similar to the bovids, the cranial material is scarce. The postcranial material can be separated into two main groups, a robust and a slender one. The robust postcranials can be assigned to Hippotherium brachypus, which is the most common robust hipparionine species in Greece during the Turolian. The identification of the slender hipparionine material is more delicate, due to the existence of several potential taxa, which are usually identified based on cranial and dental material. Only two fragmentary crania have been found so far. Neither of them can be assigned to H. brachypus, whereas both of them differ significantly from each other to be assigned to the same species. A juvenile cranium, from the site K4, has a single, well-developed, and deep preorbital fossa, which is situated near the orbit. These features are typical for the Cremohipparion lineage, in particular Cremohipparion mediterraneum. An adult cranium, originating from the initial excavation site (Ke), features a weakly developed preorbital fossa without posterior pocketing, placed far from the orbit, whereas its upper dentition is moderately plicated. These features resemble closer the Hipparion dietrichi - Hipparion prostylum lineage. Thus, it may be assumed that Kerassia was inhabited by two slender hipparionine species. In the lower horizon the slender hipparionines are more frequent, while in the upper horizon the robust H. brachypus is more common. The Rhinocerotidae from Kerassia have been studied in detail (Giaourtsakis et al., 2006; Athanassiou et al., 2014), and are represented by three species: the tandem-horned rhinocerotids "Diceros" neumayri and Dihoplus pikermiensis, along with the hornless species Acerorhinus neleus. "Diceros" neumayri is the dominant rhinocerotid taxon, and the only one that occurs in both fossiliferous horizons, so far. The family Chalicotheriidae is represented in both horizons by a few specimens, which are attributed to the schizotheriine Ancylotherium pentelicum (Kampouridis & Dimakopoulos, 2018). The family Giraffidae is well-represented in Kerassia. Five different species have been identified: Palaeotragus rouenii, Palaeotragus sp., Helladotherium duvernoyi, Bohlinia attica and Samotherium major (Iliopoulos, 2003). Notably, four species coexist in each fossiliferous horizon (Fig. 1). The carnivorans include seven species, the hyaenids Plioviverrops sp., cf. Ictitherium pannonicum, Hyaenotherium wongii, Adcrocuta eximia, the felids Amphimachairodus giganteus, Metailurus parvulus and the mustelid ?Promeles palaeatticus (Iliopoulos, 2003; Roussiakis & Theodorou, 2003; Roussiakis et al., 2006). The proboscideans are scarce but diverse, comprising three species: Deinotherium cf. proavum, Konobelodon atticus and Choerolophodon sp. (Theodorou et al., 2001; Kampouridis & Dimakopoulos, 2018; Konidaris et al., 2014). Some additional rare taxa have been recovered so far from the upper horizon, including the suid Hippopotamodon erymanthius, the tragulid Dorcatherium sp., and the tubulidentate Amphiorycteropus gaudryi. Interestingly, remnants of a large-sized bird, attributed to Struthio sp., have been reported from both horizons, while another bird Pavo archiaci, has been only found in the site K4 (Kampouridis & Dimakopoulos, 2018).

Based on the faunal composition, a middle Turolian (MN12) age has been suggested for the fossiliferous sites of Kerassia, although an early Turolian (MN11) age cannot be decisively excluded (Athanassiou et al., 2014; Iliopoulos, 2003; Theodorou et al., 2003). Thus far, the available data are not sufficient for a more precise biochronological differentiation between the two fossiliferous horizons. The biogeographical and palaeoecological implications are of particular interest, since Kerassia seems to feature some transitional elements in its faunal composition with respect to the classical localities of Pikermi and Samos (Koufos et al., 2009). The fauna of Kerassia includes taxa like the giraffid Samotherium and the tubulidentate Amphiorycteropus, which are typically known from Samos but are notably absent in Pikermi. Conversely, Kerassia lacks the hornless rhinocerotid Chilotherium, which is characteristic for Samos, and includes Acerorhinus neleus, which occurs in Pikermi. The coexistence of numerous and dietary diverse ungulates within the faunal association of Kerassia (Iliopoulos, 2003; Solounias et al., 2010; Athanassiou et al., 2014), indicates a heterogeneous vegetational regime providing suitable dietary niches for each one of these species, and suggests a mosaic habitat of widespread open woodlands with intermittent bushlands and grassy herbaceous landscapes. Acknowledgements We would like to thank all students that participated in the excavations and in the preparation of the material. The excavations between 1992 and 2015 were funded by local authorities, the General Secretariat for Research and Technologies of Greece and the NKUA Research Account projects 70/4/1394, 70/3/2842, 70/3/3922, 70/3/8567 and 70/3/12301. Participation in the conference has been supported by the Palaeontological Association. References Athanassiou, A., Roussiakis, S., Giaourtsakis, I., Theodorou, G., Iliopoulos, G., 2014. A new hornless rhinoceros of the genus Acerorhinus (Perissodactyla: Rhinocerotidae) from the Upper Miocene of Kerassiá (Euboea, Greece), with a revision of related forms. Palaeontographica, Abt. A: Palaeozoology – Stratigraphy 303 (1-3), 23-59. Giaourtsakis, I., Theodorou, G., Roussiakis, S., Athanassiou, A., Iliopoulos, G., 2006. Late Miocene horned rhinoceroses (Rhinocerotinae, Mammalia) from Kerassia (Euboea, Greece). N. Jb. Geol. Palaont. Abh. 239, 367-398. Iliopoulos, G., 2003. The Giraffidae (Mammalia, Artiodactyla) and the study of histology and chemistry of fossil mammal bone from the Late Miocene of Kerassia (Euboea Island, Greece). Ph.D. Thesis, University of Leicester, Leicester, 147 p. Kampouridis, P., Dimakopoulos, G., 2018. Taxonomic identification of the Turolian fauna of Kerassia, Euboea (Greece). Undergraduate Thesis, National and Kapodistrian University of Athens, Athens, 131 p. Konidaris, G., Roussiakis, S., Theodorou, G., Koufos, G., 2014. The Eurasian occurrence of the shovel-tusker Konobelodon (Mammalia, Proboscidea) as illuminated by its presence in the Late Miocene of Pikermi (Greece). Journal of Vertebrate Paleontology 34 (6), 1437-1453. Koufos, G., Kostopoulos, D., Merceron, G., 2009. The Late Miocene Mammal Faunas of the Mytilinii Basin, Samos Island, Greece: New Collection 17. Palaeoecology – Palaeobiogeography. Beiträge zur Paläontologie 31, 409-430. Roussiakis, S., Theodorou, G., 2003. Carnivora from the Late Miocene of Kerassia (Northern Euboea, Greece). Deinsea 10, 469-497. Roussiakis, S., Theodorou, G., Iliopoulos, G., 2006. An almost complete skeleton of Metailurus parvulus (Carnivora, Felidae) from the Late Miocene of Kerassia (Northern Euboea, Greece). Geobios 39, 563-584. Solounias, N., Rivals, F., Semprebon, G. M., 2010. Dietary interpretation and paleoecology of herbivores from Pikermi and Samos (late Miocene of Greece). Paleobiology 36 (1), 113-136. Theodorou, G., Athanassiou, A., Iliopoulos, G., 2001. Proboscidea from the Late Miocene of Kerassiá (Euboea, Greece). 45th Annual Meeting of the Palaeontological Association, Copenhagen. The Palaeontology Newsletter 48 (suppl.), p. 50. Theodorou, G., Athanassiou, A., Roussiakis, S., Iliopoulos, G., 2003. Preliminary remarks on the Late Miocene herbivores of Kerassia (Northern Euboea, Greece). Deinsea 10, 519-530.

ABSTRACT. Stochastic models accept that some aspects of a physical process cannot be explained or incorporated into the model and must be represented by some random process, in order to cope with the uncertainties. The stochastic model is used as a basis for planning, data analysis and prediction (or decision making -depending on the process). In that sense, stochastic models are often useful in seismology. In this framework the following five basic stochastic models are presented: the Stress Release Model, the semi-Markov Model, the Hidden Markov Model, the Hidden semi-Markov Model and the Markovian Arrival Process. Each of these models is used in modeling seismic processes, in order to extract information through the associated analysis concerning seismic behavior, alike detection of change points, assessment of seismic hazard, etc.

ABSTRACT. Introduction In the last decade new and more complex physics-based simulators were developed and have acquired a growing interest as a tool for comprehension and testing of seismic process models. The earthquake simulators differ in the type of methodology developed within them and for the geometry type of the grid used in the fault model. A recent paper by Field (2019) supports the usefulness of physics-based earthquake simulators for improving overall testing procedures for earthquake forecasting. Here we apply an earthquake simulation algorithm of new generation and study its potential for modelling the long-term spatiotemporal process of strong earthquakes preparation. The algorithm of our simulator was initially introduced by Console et al. (2014), and successively modified by Console et al. (2017, 2018). In this improved version a specific seismogenic structure is modelled by quadrilateral faults constituted by thousands of cells with sides of 1 km or less. Note that modelling the seismic sources by numerous segments of rectangular or trapezoidal shape is just a convenient tool for the simplicity of the algorithm used in the physics-based simulator code, but definitely does not limit a rupture to expand beyond the edges of such segments. The physical model on which the latest version of our simulation algorithm is based also includes, besides tectonic stress loading and static stress transfer as in the previous versions, the Rate & State constitutive law. The simulator code needs relatively modest computer resources and is capable for simulating tens of thousands of years of seismic activity producing catalogues of tens of thousands of events in a wide magnitude range. The resulting synthetic catalogues exhibit typical magnitude, space and time features, which are comparable with those of real observations. In this study we applied the simulator code to a physical model for the Corinth Gulf (Greece) fault system, a well-known seismic structure about 100 km long, where several earthquakes of magnitude larger than 6.0 occurred in the last few centuries. This structure is typically modelled after being subdivided into eight major fault segments characterized by different slip-rates, which can rupture either separately or simultaneously (Console et al., 2015). The results of this simulation provide interesting inferences on the spatiotemporal properties of seismic activity in the study area. In particular, the recurrence time of the larger events and their spatial relation are investigated. Application to the seismicity of the Corinth Gulf fault system By means of a set of preliminary trials, the values of the free parameters characterizing the simulation algorithm were set up in order to obtain a synthetic catalogue reproducing realistic features of the real observations, including the b-value of the frequency-magnitude distribution. The simulation was run over a period of 100 kyr, preceded by a warm up period of 10 kyr not used in the output catalogue. Some results of the synthetic catalog are reported in Table 1. Table 1. Features of the 100,000 yr synthetic catalogue in the Corinth Gulf fault system Number of earthquakes of M ≥ 4.0 158,923 Number of earthquakes of M ≥ 5.0 68,321 Number of earthquakes of M ≥ 6.0 3,931 Number of earthquakes of M ≥ 6.5 632 Maximum likelihood b-value (M ≥ 4.5) 0.80 Largest magnitude Mmax 6.81 Annual seismic moment M0 (M ≥ 4.0) 2.66E+17 Nm/yr Number of earthquakes of M ≥ 6.0 rupturing only one segment 2,365 Number of earthquakes of M ≥ 6.0 rupturing at least two segment 1,566 Largest number of segments ruptured in one earthquake of M ≥ 6.0 5

Recurrence of large magnitude earthquakes in the synthetic catalogue We examined the statistical features of the synthetic catalogue referring to the long term series of large magnitude earthquakes for some specific seismogenic faults of the study area. In order to carry out a statistical analysis of the earthquake recurrence intervals, we need a quantitative, even if somehow arbitrary, definition to identify in a seismic catalogue the events to which we want to apply such analysis. For a more in-depth discussion of this issue, we refer to Field (2015) addressing the “recurrence of what?” question. There could be two ways for associating earthquakes to specific segments. These ways can be termed either “nucleation” or “participation” (Parsons et al., 2018). Once we have selected a segment to be studied, by the nucleation criterion we take only earthquakes encompassed in the considered segment. In this case, each earthquake can be associated to one segment only, even if it has substantially ruptured more than one segment. This criterion may lead to underestimation of the hazard assessment of a specific site, because a very large earthquake rupturing a segment close to that site might be ignored in the analysis, if its hypocenter was located into a different source. Moreover, we should consider the fact that frequently seismic catalogues provide the hypocentral coordinates of a large earthquake outside any segment reported in the adopted geological model. By the participation criterion we associate to a specific segment all the large earthquakes that have ruptured a substantial part of this seismic source. In this way, any single earthquake can be counted more than once in the recurrence analysis of different sources. The participation criterion can be applied to the synthetic catalogue generated by our simulation algorithm because the output file contains the number of cells ruptured by each earthquake for any segment. In this analysis, we have adopted the participation criterion by applying the following empirical rules: 1) a magnitude threshold of 6.0 for the considered earthquake is assigned; 2) the earthquake is initially assigned to the segment containing the nucleation cell of the earthquake; 3) if the equivalent magnitude estimated by the number of cells ruptured by the earthquake in one of any other segments is larger than the minimum magnitude assigned by rule 1, then this segment can be associated to the same earthquake; 4) if the earthquake ruptured at least 70% of the cells of a segment, then this segment can also be associated to this particular earthquake. In this way, we counted through the whole 100 kyr synthetic catalogue the number of times that a given fault segment has participated in any M ≥ 6.0 earthquake alone (2,365 times) or jointly with other segments (1,566 times). In six cases, five segments ruptured all together in one single very large earthquake (Table 1). In order to assess whether the earthquake occurrence time on single segments in the synthetic catalogue behaves either as a Poisson process or it rather exhibits some pseudo-periodical feature, we carried out a statistical analysis of the inter-event times for the entire 100 kyr simulation. The analysis focused on the sources listed in Table 2, which displays the mean inter-event time, the standard deviation, and the coefficient of variation of each analysed segment, for the earthquakes fulfilling the four above-mentioned empirical rules. This Table also reports the results of the difference between the log likelihood computed by the Brownian Passage Time (BPT) renewal model and the Poisson time-independent model (dlogL). For the likelihood estimation we adopted the values of Tr and Cv reported in Table 2 for each segment. Table 2. Statistical parameters obtained for some sources of the 100,000 yr synthetic catalogue associated to earthquakes of M≥6.0 Segment Number Tr (yr) sigma (yr) Cv dlogL S01 (Psathopyrgos) 169.2 108.4 0.64 208.5 S02 (Aigion) 172.9 124.1 0.72 173.6 S05 (Xylokastro) 106.6 49.9 0.47 262.0 S07 (Skinos) 226.4 99.3 0.44 172.9

The results reported in Table 2 show a moderate pseudo-periodical behaviour of strong earthquakes in all the selected sources, with a significant over-performance of the renewal BPT model with respect to the time-independent Poisson model. Other tests carried out in a similar way with different magnitude thresholds show that smaller magnitudes exhibit a less periodical and more clustered behaviour.

ABSTRACT. We examine the association of recurrence intervals and dynamic states of crustal and sub-crustal seismogenetic systems, simultaneously testing if earthquakes are generated by Poisson (uncorrelated) or Complex (correlated) processes. We apply the q-exponential distribution to the statistical description of interevent times, focusing on the joint analysis of the entropic index (measure of correlation/ dynamic state) and the q-relaxation interval (characteristic recurrence time, intrinsically dependent on the dynamic state). We examine systems in different geodynamic settings of the northern Circum-Pacific Belt: transformational plate boundaries and inland seismic regions of California, Alaska and Japan, convergent boundaries and Wadati-Benioff zones of the Aleutian, Ryukyu, Izu-Bonin and Honshū arcs and the divergent boundary of the Okinawa Trough. Our results indicate that the q-exponential distribution is a universal descriptor of interevent time statistics. The duration of q-relaxation intervals is reciprocal to the temporal entropic index and both may change with time and across boundaries so that neighbouring systems may co-exist in drastically different states. Crustal systems in transformational plate margins are generally correlated. Very strong correlation is quasi-stationary and q-relaxation intervals short and slowly increasing with magnitude; this means that on occurrence of any event, such systems respond swiftly by any magnitude anywhere within their boundaries (attributes expected of SOC). Crustal systems in convergent and divergent plate margins are no more than moderately correlated; sub-crustal systems (Wadati-Benioff zones) are definitely uncorrelated (quasi-Poissonian). In these cases q-relaxation intervals increase exponentially, but in Poissonian or weakly correlated systems they escalate much faster: moderate to significant correlation is interpreted to indicate Complexity that could be sub-critical or non-critical without a means to distinguish at present. The blending of earthquake populations from dynamically different fault networks randomizes the statistics of the mixed catalogue. A possible partial explanation of the observations is based on simulations of small-world fault networks and posits that free boundary conditions at the surface allow for self-organization and possibly criticality to develop, while fixed boundary conditions at depth do not; this applies particularly to crustal transformational systems. The information introduced by q-relaxation may help in improving the analysis of earthquake hazards but its utility remains to be clarified.

ABSTRACT. Earthquake time series are widely used to characterize the main features of regional seismicity and to provide useful insights into the earthquake dynamics. Furthermore, the temporal properties of seismicity have important implications regarding earthquake physics and probabilistic earthquake hazard assessment studies. As such, the temporal properties of seismicity have been the subject of intensive study during the past years. Research focused on whether waiting times, i.e. the time intervals between successive earthquakes, for various threshold magnitudes and spatial scales present particular scaling properties described by “universal” distributions (e.g., Bak et al., 2002; Corral, 2004), the form and the physical mechanism of which are of great importance in earthquake modeling and hazard assessments. Another main research question related to this topic is whether earthquakes occur randomly in time, following a Poisson process, or they possess some kind of “memory”, where the time of the next earthquake is related to the time of the previous ones. The present work seeks to contribute in this field. We study earthquake time series from the Corinth Rift (Greece), as well as from the Southern California and Japan. In such tectonically active regions, properties such as intermittency, fractality/multifractality and non-stationary clustering are common in earthquake time series, highlighting the complex nature of the earthquake generation process (e.g., Michas et al., 2013; Michas et al., 2015; Vallianatos et al., 2016). The probability density function of waiting times, for various time periods, spatial scales and threshold magnitudes in all three regions, exhibits bimodality and a gradual crossover between two power-law regimes at short and long waiting times, respectively (Fig.1), suggesting that the distribution is a mixture of correlated events at short timescales, induced by aftershock sequences and earthquake swarms, and correlated background activity at long timescales. Such properties indicate clustering effects at all timescales and memory in the seismogenic process. To model this behavior, we introduce a stochastic model with memory effects that reproduces the temporal scaling behavior observed in regional seismicity (Michas & Vallianatos, 2018). For nonstationary earthquake activity, where the average seismic rate fluctuates, the solution of the stochastic model is the q-generalized gamma function that presents two power-law regimes for short and long waiting times, respectively, while for stationary activity it reduces to the standard gamma function, frequently observed in stationary earthquake timeseries (Corral, 2004). The application of the derived model to the aforementioned earthquake timeseries shows that for various threshold magnitudes and spatial areas and after rescaling with the mean waiting time, the normalized probability density functions fall onto a unique curve, which is characterized by two power-law regimes for short and long waiting times, respectively, a scaling behavior that can exactly be recovered by the derived q-generalized gamma function (Fig.1). The results seem robust for nonstationary earthquake time series, despite the possible incompleteness of the earthquake catalogs, the selected threshold magnitude, or the spatial size of the chosen area, further signifying self-similarity in the temporal structure of seismicity. The results show the validity of the stochastic model and the derived scaling function, further signifying both short- and long-term clustering effects and memory in the evolution of seismicity.

ABSTRACT. Strong earthquakes (M≥6.0) may be followed by numerous aftershocks, which steadily decrease in frequency according to Omori law. The stronger aftershock usually causes catastrophic consequences as the strong earthquake that preceded has reduced the durability of buildings. The identification of certain occurrence patterns of strong aftershocks is then of both scientific and societal significance and effective tools are seeking for this scope. The monitoring of complex earthquake networks that are formed from Greek seismicity, based on the evolution of their measures, such as global efficiency, betweenness centrality and clustering coefficient is performed, aiming to identify when these networks exhibit distinct evolution between the main shock and strongest aftershocks occurrence. As network nodes the 2D seismic cells in which the study area was appropriately divided are considered and their connections among the nodes are given by the succession of earthquakes. The data are taken from a seismic catalog comprising crustal earthquakes (focal depth less than 50 km) of magnitude M≥3.0 that occurred in the territory of Greece in between 1999-2017. During this period twenty two (22) main shocks of M≥6.0 occurred, and is examined the evolution of network measures on earthquake networks before the strongest aftershocks. The earthquake networks are formed on sliding windows of a few days for monitoring the network measures variation. To assess whether the values of network measures are statistically significant the construction of randomized networks is required, and the same network measures are calculated for comparison purposes. The monitoring of network measures revealed that their values were found statistically significantly different from the corresponding values of the randomized networks shortly before the strongest aftershocks.Strong earthquakes (M≥6.0) may be followed by numerous aftershocks, which steadily decrease in frequency according to Omori law. The stronger aftershock usually causes catastrophic consequences as the strong earthquake that preceded has reduced the durability of buildings. The identification of certain occurrence patterns of strong aftershocks is then of both scientific and societal significance and effective tools are seeking for this scope. The monitoring of complex earthquake networks that are formed from Greek seismicity, based on the evolution of their measures, such as global efficiency, betweenness centrality and clustering coefficient is performed, aiming to identify when these networks exhibit distinct evolution between the main shock and strongest aftershocks occurrence. As network nodes the 2D seismic cells in which the study area was appropriately divided are considered and their connections among the nodes are given by the succession of earthquakes. The data are taken from a seismic catalog comprising crustal earthquakes (focal depth less than 50 km) of magnitude M≥3.0 that occurred in the territory of Greece in between 1999-2017. During this period twenty two (22) main shocks of M≥6.0 occurred, and is examined the evolution of network measures on earthquake networks before the strongest aftershocks. The earthquake networks are formed on sliding windows of a few days for monitoring the network measures variation. To assess whether the values of network measures are statistically significant the construction of randomized networks is required, and the same network measures are calculated for comparison purposes. The monitoring of network measures revealed that their values were found statistically significantly different from the corresponding values of the randomized networks shortly before the strongest aftershocks.

ABSTRACT. Clustering of earthquakes both in time and space is a vital aspect of seismicity, which provide information on the earthquake dynamics. For the study of the seismicity patterns and clustering characteristics in Corinth Gulf, Greece, we applied a Markovian Arrival Process (MAP) (Neuts, 1979), which is a temporal bivariate point process, with an intensity rate driven by a Markov one with unobservable states. The counting process, counts the number of events in a time interval [0,t), which are associated with the evolution of the underlying Markov process; that is, the hidden states indicate the seismicity rate. The parameters of the MAP are estimated through an EM algorithm (Dempster et al., 1977), which is iterative in that at each step it computes the log-likelihood function and reaches a local maximum after a predefined number of iterations or a convergence criterion. We followed a special structure of the rate matrices (Horvath and Okamura, 2013) where transitions among the hidden states are allowed only when arrivals are taken place. The information criterion of Akaike (Akaike, 1974) is used to determine the number of distinct seismicity rates that characterize each earthquake catalog. Residual analysis is applied to assess the goodness-of-fit of the model (Ogata, 1988), and the most likely sequence of the hidden states under which the observations occurred is computed via a local decoding algorithm. For the implementation of the algorithm the forward-backward equations are used (Mac Donald and Zucchini, 1997) and the robustness of the method is verified on synthetic catalogs where the hidden path is known. MAP is applied in the Corinth Gulf, Greece, which is a region with high seismic activity. In the study, we used the data from the catalog compiled by the Geophysics Department of the Aristotle University of Thessaloniki (Permanent Regional Seismological Network (1981)). The study area is divided in the eastern and western parts, based on seismotectonic criteria and the model is tested for different periods and magnitude thresholds in both subareas. A complete cluster analysis of the revealed path of the hidden states is given for the 135 and 139 earthquakes with M≥4.5 that occurred from 1964 to 2017 in the eastern and western parts, respectively, and the correspondence of the hidden states to the major earthquake sequences is addressed. Three states seem sufficient to describe the temporal fluctuations of earthquake occurrences for both subareas, with the lowest seismicity rate corresponding to the first one (state 1). The third state corresponds in most cases to main shocks and their immediate aftershocks. In the western part, 10 to 13 events with M≥5.5 occurred in state three, which suggests that an aftershock with M≥4.5 is expected during next hours. Our results show that the model can capture the behavior of active seismic periods revealing seismic sequences and swarms, as well periods of seismic quiescence and might be introduced as a model for change point detection able to reveal seismic clusters.

ABSTRACT. The development of fault-based long-term earthquake models is one of the key components of probabilistic hazard assessment. The main input parameter of such models is the recurrence time of strong earthquakes above a predefined magnitude threshold (e.g. M6.0) on specific faults or fault segments. These earthquakes, so called characteristic (Schwartz and Coppersmith, 1984), are considered to be identical for a given fault segment, that is to rupture the majority of the fault area, resulting in events with similar physical mechanism. Using the determined recurrence time of each segment on a given region, then one can develop an Earthquake Rupture Forecast (ERF), which returns the likelihood of the occurrence of a characteristic event in a specific time span. This forecast model can be considered either a memoryless Poisson or a renewal one, constraining the occurrence time of a future event with the date of the last one. That latter kind of models represent an elastic rebound motivated forecast (Field, 2015), in accordance with Reid’s theory (Reid, 1911). The real situation in fault zones is much more different leading the recurrence time to a complex behavior due to the interactions among fault segments due to the permanent and temporal stress perturbations (Dieterich, 1994; Stein et al., 1997), which is a potential factor that can move a fault towards or away from a future rupture. According to this conclusion, the study of recurrence time should be treated with the application of statistical approaches, rather than deterministic ones, which require the compilation of as many as possible strong earthquakes occurred in individual fault segments from all possible records, including historical, paleoseismological and instrumental catalogs. In fact, these observational data are limited because of the large interevent times between successive strong earthquakes in a given segment and consequently the related catalogs are short and incomplete. The development of earthquake simulators, introduced and applied in California (Tullis, 2012) is one powerful tool to overcome these difficulties and limitations, and can provide information on earthquake occurrence combining approximations of the known physics concerning the stress transfer, frictional properties, fault parameters and kinematics. This concept became very popular over the years due to its ability to model and reproduce long earthquake occurrence records (starting from thousands to millions of years). Following this concept, Console et al. (2015) have developed a physics-based simulator algorithm based on the modeling of the rupture growth, taking into account the long-term slip rate constrains on fault segments and without using any rheological parameter. Over the years, the simulation algorithm had an evolutionary improvement. These improved versions of the algorithm were successfully applied to simulate the Italian seismicity (Console et al., 2017, 2018a, b). In this study, a new version of the above mentioned simulation algorithms is applied, embodying in the physical processes the effect of the Rate and State Constitutive law proposed by Dieterich (1994), that contributes in the resembling of stress transfer and fault interaction in short time scales. The current version is applied in Southern Thessaly Fault Zone, which consists in the southern margin of Thessaly basin and belongs to the extensional back-arc Aegean region, that formed due to the subduction of Eastern Mediterranean oceanic lithosphere under Aegean Sea. The regional stress field is characterized by a N-S extension with relatively moderate slip rates (about 4.1 – 4.6 0.5 mm/yr) as derived from GPS measurements (Muller et al., 2013; among others). The stress is mainly accumulated on and released by six normal faults with an E-W to WNW-ESE strike as obtained from geodetic studies, fault plane solutions and field observations (Papadimitriou and Karakostas, 2003 and the references therein).Several strong earthquakes Mw6.0 have occurred in the past as inferred from both historical and instrumental earthquake catalogs. Historical information related with strong earthquake occurrence are available since the 16th century (Papazachos and Papazachou, 2002). As revealed from this information, a sequential pattern of active and inactive clustering periods is observed over the years. Focusing on the latest one during the 20th century, Papadimitriou and Karakostas (2003) showed that the stress transfer dominates the occurrence of strong earthquakes. This fact provokes the detailed study of both short and long term behavior of strong earthquakes by the application of the simulation algorithm. The simulation is implemented by modeling each one of the six fault segments as rectangular source, considered as a grid of 0.75x0.75 km squared cells. The thickness of the seismogenic layer, which is equal to 3-15 km (Hatzfeld et al., 1999), is constrained by the long-term slip rate. Taking into account that only the 60% of the total slip is released coseismically (Davies et al., 1997) the corresponding slip rate of each segment is calculated and given in Figure 1. Additionally, three free parameters must be specified before the simulation processes. These are the product Aσ of Rate and State law, the Strength Reduction (S-R) coefficient, which refers to the fault weakening and the Aspect Ratio (A-R), which discourages the rupture propagation over long distances. The selection of the three parameters is made by the application of the algorithm multiple times with different combinations among them and the comparison of each resulting catalog with a real one using the two sample Kolmogorov-Smirnov goodness of fit test. The duration of each simulation is 10kyr with a warm up period of 2kyr. The minimum magnitude generated by a two cell rupture is selected to be equal to 4.0. Based on these results, the best fitted synthetic catalog is built and used for the investigation of the strong earthquakes recurrence behavior and the renewal model was tested whether it performs better than the Poisson one. The interactions and possible triggering behavior between adjacent fault segments is studied and compared with the observed episodic occurrence of strong events. For modeling the recurrence times of each segment as a renewal process the Brownian Passage Time (BPT) distribution (Matthews et al., 2002) is adopted against the memoryless exponential one. The comparison between the models is made in terms of their log-likelihood values.

ABSTRACT. Studying the clustering features of seismicity both in space and time is one of the most important factors of earthquake forecasting. Earthquake occurrence exhibits short and long term clustering (Kagan and Jackson, 1991; Dieterich, 1994) due to the physical processes related with seismogenesis (e.g. fault interactions and heterogeneity). Focusing on short-term clustering, the seismicity can be considered as the summation of background seismicity of spontaneous earthquakes and triggered one, which dominated by foreshocks, mainshocks and aftershocks or swarm like excitations. The time span of such clustering typically ranges from several months to few years and is spatially distributed mostly around a strong event (e.g. a mainshock) of the order of a few km. Earthquake occurrence can be represented as a stochastic point process in which the occurrence rate, λ, gives the instantaneous probability of event occurrence (Daley and Vere-Jones, 2003). Despite the fact that many purely temporal models are developed, only few spatiotemporal ones have been proposed, namely the ETAS (Ogata, 1998; Console and Murru, 2001), the EEPAS (Rhoades and Evison, 2004), the double branching model (Marzocchi and Lombardi, 2008). The Epidemic Type Aftershock Sequences (ETAS) model is the most popular one for such studies and is suggested as the best for describing the short-term seismicity (Console et al., 2007).Using this model, a thorough study of the clustering features of crustal seismicity (h50 km) in Greece is conducted in both space and time during the period from 2008 up to 2017, when 17 strong events with Mw6.0 occurred. The earthquake catalog is compiled based on the recordings of the Geophysics Department of Aristotle University of Thessaloniki (GD-AUTh). With a completeness threshold of Mc=3.5 and b-value equal to 1.17 (b=1.17), 7455 events are comprised in the data set (Figure 1) provoking the detailed analysis of the spatiotemporal characteristics of short – term clustering behavior.The estimation of the model parameters is made via the MLE technique using a simulated annealing approach proposed by Lombardi (2015) implemented in the software package SEDA (Lombardi, 2017), dividing the study area by a regular grid of 0.2ox0.2o, resulted in 2080 cells in total. The meaning of estimated parameters is discussed and interpreted in connection with the physical processes related with strong earthquakes occurrence. The model is then tested by applying a residual analysis procedure. The initial estimated model including the entire dataset, underestimates the observed seismicity, while it seems to be unstable, leading to an explosive one (in other words a model with infinite decay rate). Specifically, the underestimation is observed during 2008, when five Mw6.0 occurred. Excluding the events in 2008, the estimated model exhibits good agreement with the observed seismicity. In order to develop a stable model including the 2008 seismicity, a different set of constrains concerning the 8 parameters estimation is adopted. Regarding the final suggested model, the classification between background and triggered events is made by measuring the contribution of each class to the total seismicity using the stochastic declustering method (Zhuang et al., 2002). Individual earthquake sequences occurred in different tectonic regimes are identified and compared using the stochastic reconstruction method (Zhuang et al., 2002). The stationarity of the background seismicity rate is investigated for these different areas along with the recognition of seismicity bursts or quiescence before and after major earthquakes. The present model can be considered as a reference one for the Greek territory with many potential applications including declustering the Greek earthquake catalog for time independent studies, identification of possible triggering patterns and forecasting of future strong earthquakes.

ABSTRACT. The area of Central Ionian Islands, comprising Kefalonia and Lefkada Islands, consists the most active zone in the Aegean and the surrounding area, characterized by high seismic moment rate release and frequent occurrence of strong (M≥6.0) earthquakes. The last strong event (Mw6.5) occurred on 17 November 2015 at the south western part of Lefkada Island, in less than 2 years after the occurrence in 2014 of a doublet along the western part of Kefalonia Island (with Mw6.1 and Mw6.0), with the two main events being separated temporally by seven days and associated with adjacent fault segments (Karakostas et al., 2015; Papadimitriou et al., 2017). The above agrees with the observation that one of the most important features of seismic activity is its tendency to clustering. It is widely recognized that the seismicity rate increases after a large earthquake for several years and at distances distinctly larger than the fault length. Since the area under study is characterized by remarkable temporal closeness of strong events, their tight clustering implies significant interaction on adjacent fault segments (Papadimitriou et al., 2017) and can be explained through stress transfer (Papadimitriou, 2002). Since strong events in the region have caused severe damage and numerous casualties, it is important to set up a real time evaluation of the evolution of aftershock activity. Aiming to investigate short-term interactions and find seismicity patterns, even if the information contained in a good historical catalog cannot be substituted, physics-based simulators created with characteristics based on the Central Ionian Islands faulting properties can overcome the lack of long historical data and provide us reliable information. In order to investigate clustering features in a larger time window in comparison to the short duration of historical and instrumental records thus, the use of a newly developed earthquake simulator is proposed providing the opportunity of dealing with a catalog lasting 10kyr, i.e., of much larger duration (Console et al., 2015, 2017, 2018a, b). The free parameters of the simulator are the strength reduction coefficient (S-R), which is a weakening mechanisms, the aspect ratio coefficient (A-R), which controls the rupture propagation, and Aσ related to the Rate and State Constitutive law. A synthetic catalog with time, space and magnitude behavior comparable to the observed seismicity is compiled, where substantial similarity is observed between the observed (magenta line) and the calculated annual rate (red line in Figure 1). A temporal feature obtained from the simulator algorithm can be explored by analyzing the statistical distribution of the time by which an event can precede or follow a strong earthquake. For that purpose a stacking technique is applied and all events with M≥6.0 included in the 10kyr catalog, are scanned for a time period of 0.5 years before and 0.5 years after the occurrence of the main shock. The total number of events with M≥3.6 preceding and following the mainshock in each bin for the whole time period considered is shown in Figure 2. A sudden raise is clearly observed soon after the occurrence of a large event, indicating the presence of a feature resembling the aftershock activity. The clustering features and patterns of the synthetic seismicity are also investigated by means of the spatio-temporal Epidemic Type Aftershock Sequence (ETAS) branching model that has been widely and successfully applied to quantify earthquake interrelations (Console and Murru, 2001; Console et al., 2003). The synthetic data are subdivided in smaller periods in order to test the performance of the model within periods of equivalent duration to the real case. Comparison is performed with the results provided by the application of the ETAS model in the Central Ionian Islands fault system, using as a learning period the period from 2008 until 2014, i.e. approximately 7 years. Although the synthetic data adequately match the real data as shown by statistical tests (Kolomogorov Smirnov test, Wilcoxon rank sum test), some discrepancy is observed between the estimated parameters when the ETAS model is applied. This could be explained by the fact that the study period in the real case is characterized by intense seismic activity with 3 strong events (M_w≥6.0) in a period of 2 years, which is not the case in the subdivided periods of 7 years in the simulated data.

Conclusions Our preliminary results show that the spatial rather than the temporal features of the model are more stable. It is intriguing exploiting more deeply the performance of the clustering model using the synthetic catalog generated through the physics-based simulator in order to find features and patterns – both temporal and spatial – of short-term seismicity. Acknowledgements This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning» in the context of the project “Strengthening Human Resources Research Potential via Doctorate Research” (MIS-5000432), implemented by the State Scholarships Foundation (ΙΚΥ). References Console, R., Murru, M., 2001. A simple and testable model for earthquake clustering. Journal of Geophysical Research, 106, 8699–8711. Console, R., Murru, M., Lombardi, A. M., 2003. Refining earthquake clustering models. Journal of Geophysical Research, 108, 2468, doi: 10.1029/2002JB002130. Console, R., Carluccio, R., Papadimitriou, E. & Karakostas, V., 2015. Synthetic earthquake catalogs simulating seismic activity in the Corinth Gulf, Greece, fault system, Journal of Geophysical Research, 120(1), 326–343. Console, R., Nardi, A., Carluccio, R., Murru, M., Falcone, G., Parsons, T., 2017. A physics-based earthquake simulator and its application to seismic hazard assessment in Calabria (Southern Italy) region. Acta Geophysica, 65, 243–257. Console, R., Chiappini, M., Minelli, L., Speranza, F., Carluccio, R. & Greco, M., 2018a. Seismic hazard in Southern Calabria (Italy) based on the analysis of a synthetic earthquake catalog. Acta Geophysica, doi: 10.1007/s11600-018-0181-7. Console, R., Chiappini, M., Minelli, L., Speranza,F., Carluccio, R., Greco, M., 2018b. Seismic hazard in Southern Calabria (Italy) based on the analysis of a synthetic earthquake catalog. Acta Geophysica, doi: 10.1007/s11600-0181-7. Karakostas, V., Papadimitriou, E., Mesimeri, M., Gkarlaouni, Ch., Paradisopoulou, P. 2015. The 2014 Kefalonia doublet (Mw6.1 and Mw6.0) central Ionian Islands, Greece: seismotectonic implications along the Kefalonia transform fault zone. Acta Geophysica, 63, 1–16, doi:10.2478/s11600-014-0227-4. Papadimitriou, E. E., 2002. Mode of strong earthquake occurrence in central Ionian Islands (Greece). Possible triggering due to Coulomb stress changes generated by the occurrence of previous strong shocks. Bulletin of Seismological Society of America, 92, 3293–3308. Papadimitriou, E., Karakostas, V., Mesimeri, M., Chouliaras, G., Kourouklas, Ch., 2017. The Mw6.5 17 November 2015 Lefkada (Greece) Earthquake: Structural Interpretation by Means of the Aftershock Analysis. Pure & Applied Geophysics, 174, 3869–3888.

ABSTRACT. The Hellenides have been developed within a segment of the Tethys Ocean between Eurasia and Gondwana of the Pangaea configuration, since the Early Triassic. Their paleogeographic evolution was characterised by an opening phase throughout Early Triassic – Late Jurassic and a closing phase from Late Jurassic to present. The Tethyan realm was rather complicated as there were several microcontinents / terranes, drifting from the Gondwana / African passive margin to the European active margin. Thus, a number of distinct oceanic basins was opened and closed in between the northwards drifting continental fragments, which were gradually accreted to the European margin. Major subduction zones and orogenic arcs were associated to the Axios / Vardar oceanic basin in Late Jurassic-Early Cretaceous, sutured between the Rhodope and Pelagonian terranes, the Pindos / Cyclades basin in Late Cretaceous-Eocene, sutured between the Pelagonian / Internal and the Apulia / External Carbonate Platforms and the East Mediterranean basin, subducting since Late Miocene, between the External Carbonate Platform and Africa. The overall development of the orogenic wedges and the resulting new Hellenic continental crust is maintained through compressional and extensional detachments at subcrustal scale, involving tectonic wedges of shallow sedimentary and deeper metamorphic units.