Paleoenvironmental Changes in Arctic Chukotka during the Early Pleistocene (Marine Isotope Stages 91-82)

The continuous palynological record from Lake El'gygytgyn , approximating marine oxygen isotope stages (MIS) 91-82, reflects the response of plant communities in arctic Chukotka to interglacial, glacial, and interstadial climates. According to the current lake age model, the 12 pollen zones described in this paper correspond to the interval 2.350-2.146 Ma BP, the upper limit of which is determined by the Reunion paleomagnetic event (2.140 Ma BP). However, multiple discrepancies between pollen zone and MIS boundaries show the need for a thorough revision of the chronology for the lake sediments. Given the current age scheme, the warmest climatic conditions occurred during MIS 91, whereas the coldest interval corresponds to the second half of MIS84. Interglacial vegetation was Larix forest with Pinus sibirica, Abies, and Picea. A mix of Larix forest-tundra and shrub tundra characterized cooler climates.