Выпуск: 1-2 , Том: 299 , Год издания: 2011

The three main Lena Delta terraces were formed during different stages of the late Quaternary. While only the first floodplain terrace is connected with active deltaic processes, the second and third terraces, which dominate the western part of the delta, are erosional remnants of arctic paleolandscapes affected by periglacial processes. The landscape dynamics of the second and the third terraces, and their relationship to each other, are of particular importance in any effort to elucidate the late Quaternary paleoenvironment of western Beringia.Multidisciplinary studies of permafrost deposits on the second terrace were carried out at several sites of the Arga Complex, named after the largest delta island, Arga-Muora-Sise. The frozen sediments predominantly consist of fluvial sands several tens of meters thick, radiocarbon-dated from > 52 to 16. kyr BP. These sands were deposited under changing fluvial conditions in a dynamic system of shifting river channels, and have been additionally modified by synsedimentary and postsedimentary cryogenesis. Later thermokarst processes affected this late Pleistocene fluvial landscape during the Lateglacial and the Holocene. In addition, eolian activity reworked the fluvial sands on exposed surfaces at least since the Lateglacial, resulting in dune formation in some areas.