Holocene ice wedges of the Kolyma Lowland and January paleotemperature reconstructions based on oxygen isotope records

Abstract

Ice wedges in the Holocene deposits of alases and floodplains have been studied in the Kolyma Lowland region. Most ice wedges have been found within alases dated to between 11 and 4.2 cal kyr BP, corresponding to the Greenlandian and Northgrippian stages of the Holocene. This study confirms that the greatest intensity of ice wedge growth occurred during ~10.5–6 cal kyr BP. A decrease in their growth was mainly caused by alas draining and reduced sedimentation. In the last 4–4.5 cal kyr BP (defined as the Meghalayan stage of the Holocene), ice wedges continued to grow in old alases, sometimes as a younger generation, as well as within young alases and floodplains of the Kolyma River and its tributaries. Mean January air temperatures were quite stable during the Holocene and varied usually approximately between −33 and −41°C, with a slight cooling during the Meghalayan stage. Minor variations in mean January air temperature may indicate a stability of winter climate of northern Yakutia, probably as a result of the stable influence of the Siberian anticyclone.