Environmental changes in the eastern Arctic 1.6975-1.965 Ma, palynological investigations from El’gygytgyn Lake, northeastern Russia

Abstract

The 1.6975–1.965 Ma (MIS 60–MIS 74) portion of the El'gygytgyn Lake record includes two key chronostratigraphic markers in the Calabrian–Gelasian boundary (1.806 Ma) and the Olduvai paleomagnetic excursion (1.77–1.95 Ma). It also provides the first paleovegetation information for these times from the eastern Arctic. Palynological data indicate the dominance of Larix forest and forest-tundra during warm and cool intervals, which differs sharply from the herb tundra which characterized glacial intervals of the Middle and Late Pleistocene. These forests likely included tree species of Betula and Alnus and perhaps Populus and Chosenia. The persistence of Larix indicates summer temperatures were warmer than present. Pinus pumila, a typical interglacial taxon, is restricted to MIS 65 and MIS 71, suggesting other intervals experienced dry winters. Cool and warm periods are clearly marked by vegetation changes during the Late Gelasian Stage, but a dominance of Poaceae pollen and reduction in Alnus pollen during the Early Calabrian Stage mutes the climatic fluctuations. The loss of Alnus perhaps relates to decreases in seasonal temperatures.