Late Pleistocene Events in Beringia

Abstract

The region of the western Arctic, stretching from the Lena River in northeast Russia to the Mackenzie River in Canada, is geographically know as Beringia. The lowlands of Beringia remained ice-free during Pleistocene glaciations, while nearly all other high latitude regions of the Northern Hemisphere were covered by ice sheets. The lowering of sea level during glacial stadials exposed large regions of the Bering and Chukchi sea shelves, repeatedly forming the Bering Land Bridge. The Bering Land Bridge cut off circulation between the waters of the North Pacific and Arctic oceans, greatly increasing the continentality of adjacent land masses, and diminishing the in-land flow of relatively warm, moist air masses from the North Pacific. Late Pleistocene glaciations in Beringia included rapid expansion of valley glaciers directly after the last interglacial interval (MIS 5e). Glaciation during MIS 4 is referred to as the early Wisconsin in North America and the Zyryan in northeastern Russia. With the exception of the Alaska Range and Chugach/St Elias Mountains, the MIS 4 glacial ice caps and mountain glacier complexes throughout much of Beringia were considerably more extensive than during the subsequent late Wisconsin/Sartan glaciation in MIS 2.