The paper presents an approach to modeling and study of argumentation found in popular science literature. The study of argumentation is performed by means of comparative analysis of discourse structures. Different types of argumentative structure are considered and the co-occurrence of arguments “from Expert opin-ion” with other types of argumentative reasoning typical of the popular science genre is analyzed. With the view of automatic extraction of argumentative rela-tions, the analysis of correlation between rhetorical and argumentative annotations was carried out. The experiment was conducted on a corpus of 11 articles of the popular science genre from the Ru-RSTreebank.