НОВЫЕ НАХОДКИ И СТРАТИГРАФИЧЕСКОЕ РАСПРЕДЕЛЕНИЕ ФОРАМИНИФЕР В ПОГРАНИЧНЫХ ПЕРМСКО-ТРИАСОВЫХ ОТЛОЖЕНИЯХ ЮЖНОГО ВЕРХОЯНЬЯ

Abstract

The first results made on the study of foraminifera from Permian-Triassic boundary deposits in the South Verkhoyan Region (the lower part of the Nekuchan Formation, the Suol section, the Setorym River basin, tributary of the Vostochnaya Khandyga River) are presented. The foraminifera are a new group for this section and were not used in paleontological stratigraphic studies before. The foraminiferal assemblage is represented exclusively by ammodiscids (genera Ammodiscus, Glomospira, and Glomospirella), among which Ammodiscus septentrionalis Gerke dominates. The distribution of foraminifera in the Suol section is compared with the previously constructed carbon isotope curve, which reflects global environmental changes. Three intervals are identified in the stratigraphic distribution of foraminifera. In the lower interval, foraminifera are relatively numerous and diverse. In the middle interval foraminifera were not detected; here the maximum negative values of the δ13Сorg isotope are also recorded. This interval, obviously, corresponds to the time of the main fauna extinction in the Tethyan basins. In the upper interval, a gradual recovery of the abundance and structure of the foraminiferal complex occurs. A comparative analysis of the distribution and dynamics of taxonomic rearrangements of foraminiferal associations in the Permian-Triassic deposits in the Suol section with Tethyan and Boreal sections was carried out, some general features and patterns are established. A brief description of four of foraminiferal species and a photo table with their image are given.