New AMS Dates of Organic Microinclusions in Ice Wedges from the Lower Part of Batagay Yedoma, Yakutia

Abstract

Accelerator mass spectrometry dating of organic microinclusions was performed on eight samples from the lower part of the thick Pleistocene syngenetic ice wedges exposed in the Batagay mega-slump in northern Yakutia, the upper reaches of the Yana River (67.58° N, 134.77° E). Radiocarbon dating suggests that ice wedge growth took place between 38 120 and 45 570 14C BP (42.1–49 cal ka BP). The Late Pleistocene mean January air temperatures from 42 to 49 cal ka BP have been reconstructed from the isotope data for the Batagay section and a number of reference sections in northwestern Yakutia. The lowest mean January air temperature of –51°С for this period was in Batagaika, whereas in the areas located 500–600 km to the north, it was 5–7°C higher. This is accounted for by the influence of the Yakutian anticyclone in winter during the Late Pleistocene from 42 to 49 cal ka BP, which was as pronounced at that time as it is now.