ИСТИНА

Batagay megaslump exposed the greatest geocryological formation known in the world in the north of Central Yakutia in the upper reaches of Yana River (67°34'49"N, 134°46'19"E). A vertical wall of 70 to 100 m exposes the yedoma with thick syngenetic ice wedges, underlying by older horizontally layered frozen sediments with narrow ice wedges. Mean values of δ18O in the ice wedges from three sections varies in a narrow range from –34.36 to –34.12 ‰, and δ2H values from –266.3 to –264.5 ‰. Based on detailed isotope data (170 samples), the average January temperature of the Late Pleistocene was calculated from 25 to 30 cal. ka BP and from 42 to 49 cal ka BP for the Batagay section and for a number of supporting sections, in the north-west of Yakutia. It was shown that the lowest average January air temperature in this period was in the Batagay region (–51°С, average january temperature is -45°C), while in areas located 500-600 km to the north, it was 4-5°С higher 25 to 30 cal ka BP and 5-7°С higher from 42 to 49 cal ka BP. These severe winter climate conditions are explained by the existence by stable Yakutia anticyclone in the Late Pleistocene (from 25 to 49 cal ka BP), which still exists at present.