AMS 14C Dating of Pollen Concentrate from Late Pleistocene ICE Wedges from the Bison and Seyaha Sites in Siberia

Abstract

Accelerator mass spectrometry (AMS) radiocarbon dates of pollen concentrate were obtained from multistage syngenetic ice wedges of cross-sections from the Late Pleistocene Bison site, located along the Lower Kolyma River (68 degrees 34'N, 158 degrees 34'E), from ~43,600 to ~26,200 BP, and 3 AMS 14C dates of pollen concentrate in ice wedges from the Seyaha site cross-section, located on the east coast of the Yamal Peninsula (70 degrees 10'N, 72 degrees 34'E), from ~22,400 to ~25,200 BP. Pollen concentrate samples were prepared using a special pretreatment procedure. Pollen and spores from ice-wedge ice signalize a regional pollen rain. Therefore, 14C-dated extracts of pollen and spores from ice-wedge ice enable an adequate reconstruction and chronology of landscape dynamics on a regional scale. The pollen and spores were well preserved despite numerous redepositions in the penecontemporaneous structure in which they were found. Thus, a comparison with dates on other fractions from the same sample is necessary. The youngest date is the most reliable among the intersample AMS 14C dates from the ice and permafrost sediments.