Northeast Siberian Permafrost Ice-Wedge Stable Isotopes Depict Pronounced Last Glacial Maximum Winter Cooling

• Main Authors: Wetterich, S., Meyer, H., Fritz, M., Mollenhauer, G., Rethemeyer, J., Kizyakov, A., Schirrmeister, L., Opel, T.
• Format: Article in Journal/Newspaper
• Language: English
• Published: AMER GEOPHYSICAL UNION 2021
• Subjects: ddc:no; Ice; permafrost; wedge*; Beringia; Siberia
• Online Access: https://kups.ub.uni-koeln.de/58158/

Stable isotopes (delta O-18, delta D) of wedge ice hold potential to reconstruct past winter climate conditions. Here, we present records of the marine isotope stages (MIS) 3 and 2 including the last Glacial maximum (LGM) from Bol'shoy Lyakhovsky Island (NE Siberia). MIS 3 wedge ice dated from 52 to 40 Kyr b2k varies between -32 and -29 parts per thousand in delta O-18. Colder LGM conditions are implied by delta O-18 of -37 parts per thousand around 25 Kyr b2k. Similar Deuterium excess values indicate comparable moisture sources during MIS 3 and MIS 2. Regional LGM climate reconstructions depend on the seasonal resolution of the proxies and model simulations. Our wedge-ice record reflects coldest winters during global minima in atmospheric CO2 and sea level. The extreme LGM winter cooling is not represented in model projections of global LGM climate where West Beringia shows noticeably little cooling or even warming in mean annual temperatures compared to the late Holocene.