Pollen characteristics of Zelyony Mys yedoma and ground squirrel' burrows

Abstract

The pollen characteristics of the Zelyony Mys yedoma record cyclical changes in vegetation cover, both on a local and regional scale. There are three local pollen zones such as: Varia +Artemisia, Varia + Selaginella sibirica, and Pinus + Betula sect. Nanae. Pollen spectra reflect open landscapes of mosaic hypo-arctic tundra. Some local pollen zones in the ice wedges correspond to the local pollen zones of yedoma: Varia + Selaginella sibirica dates from 41.9-33.8 CalBP, Pinus + Betula sect. Nanae (P+B) is approximately dated to 33.5-30 CalBP. Reconstruction of the annual thawing index showed several fluctuations: two short-term periods of significant deterioration of vegetation conditions (annual thawing index was about 200-300 deg. × days, about 46, 34-33 CalBP), and two periods of improvement of vegetation conditions 45-43 and 32 CalBP (annual thawing index was about 600-750 deg. x days). Regional pollen in burrows is the same in synchronous horizons of yedoma. Noticeable amount of larch pollen (10%) in the fossil burrows in the Zelyony Mys yedoma showed that favorable conditions are created in the burrows for the preservation of larch pollen. The seeds found in minks reflect animal dietary preferences and only partlially local vegetation around minks. Reconstruction of positive temperature sums indicates the palinospectra reflect three-fold fluctuations of vegetation conditions: two short periods of substantial deterioration of vegetation conditions (the sum of positive temperatures is about 200-300 degrees x days), about 46, 34-33 thousand years (and two periods of improvement of vegetation conditions 45-43 thousand years (sum of positive temperatures about 600 degrees x days) and 32 thousand years (sum of positive temperatures about 750 degrees x days).