The first AMS radiocarbon dates of organic matter microinclusions in the ice wedge of the upper part of the Batagay yedoma megaslump, Yakutia

Abstract

Microinclusions of organic matter were dated using acceleration mass spectrometry in seven samples from the upper part of the thick Pleistocene syngenetic ice wedges uncovered in the outcrop of the Batagay yedoma located in northern Yakutia along the upper Yana River (67,58 N, 134,77 E). The dated fragment of ice wedge was formed within 22 760-20 010 radiocarbon years BP (or 27 100-33 800 cal BP). Using detailed isotope data, the January average air temperature in the Late Pleistocene (25-30 cal kyr BP) was calculated for the Batagay section along with a series of reference sections in northwestern Yakutia. It was shown that the minimum January average air temperature (-51 C) was characteristic at that time for the area of the Batagaika crater, with values 4-5 higher in areas 500-600 km further north. This effect was caused by the occurrence of the Yakutian anticyclone in winter during the Late Pleistocene, which was just as pronounced as that at the present time.