The First AMS Dating of Organic Microinclusions in an Ice Wedge of the Upper Part of the Batagay Yedoma Megaslump (Yakutia)

Resumo

Microinclusions of organic matter were dated using acceleration mass spectrometry in seven samples from the upper part of the thick Pleistocene syngenetic ice wedge exposed 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 veins were formed within 22 760–29 910 radiocarbon years BP (or 27.1–33.8 cal BP) ago. Using detailed isotope data, the January average air temperature in the Late Pleistocene (27–30 cal 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°C higher in areas 500–600 km further north. This effect was caused by the occurrence of the Yakutia anticyclone in winter during the Late Pleistocene, which was just as pronounced as that at the present time.