Paleoenvironmental changes in northern Chukotka during marine isotope stages 12-17

The continuous palynological record of sediments from the El'gygytgyn crater lake document the changes in vegetation during marine isotope stages 12-17, which span the interval between 424,000 and 712,000 years ago. An important chronological reference point for this interval is the Brunhes-Matuyama boundary (781,000 years ago), established by paleomagnetic analysis of the lake sediments. The regional vegetation of the warm interglacial stages was characterized by the widespread presence of larch forests, which included thickets of dwarf birch, alder, and dwarf pine. In the cold stages, a mosaic of herb tundra dominated, giving way to forest-tundra communities in the valleys of the Anadyr Plateau that surrounds the lake. In the interval between 424,000 and 712,000 years ago, the warmest climate occurred during MIS15, whereas the most severe cooling occurred during MIS12.