Bioindicators of the Upper Neopleistocene Karginsky and Sartansky Deposits of the Kolyma Lowland and Features of Their Taphonomy under Multiple Exposure to Cryogenic Factors

Abstract

The paper presents the results of the study of Karginsky and Sartansky deposits of the Kolyma Lowland, synchronous with marine isotope stages (MIS) 3 and 2, and microphytofossils from them. During the accumulation of Karginsky deposits, various landscapes existed in this territory: communities of humid and dryish tundras, larch sparse forests, and tundra swamps, including habitats occupied by pioneer and steppe vegetation. The Sartansky deposits were formed under more uniform, cold and dry conditions. The results of the microbiomorphic study indicate the predominance of tundra herbaceous, mainly cereal associations in combination with the moss cover. Satisfactory preservation of microphytofossils from these strata is due to the specificity of the cryolithozone with a predominance of low temperatures throughout the year and low microbiological activity. The presence of spores and pollen with physical damage (ruptures and cracks) and corroded forms of phytoliths can be associated with their presence in the seasonally thawed layer during alternating freezing and thawing cycles.