Yedoma Permafrost Landscapes as Past Archives, Present and Future Change Areas.Microbial and Geochemical Evidence of Permafrost Formation at Mamontova Gora and Syrdakh, Central Yakutiaстатья
Аннотация:Yedoma Permafrost Landscapes as past Archives, Present and Future Change Areas / L. Schirrmeister, A. N. Fedorov, D. Froese et al. — Lausanne, Switzerland: Lausanne, Switzerland, 2022. — 460 p. Ice-rich permafrost deposits of late Pleistocene age (Yedoma Ice Complex) covered several million km2 of the Arctic main land between the Taymyr Peninsula and the Yukon of Northwest Canada, from central Yakutia to the Arctic shelves during the Last Glacial Maximum. Today about 1.9 million km2 in Siberia, Alaska, and Northwest Canada are considered the modern remains of this Yedoma domain. Similar cold and dry climate conditions in different regions contributed to the prevalence of common deposit features such as relative fine-grained sediments, large syngenetic polygonal ice wedges, specific ground ice structures, significant amounts of buried well-preserved organic matter, and fossil remains of the mammoth megafauna and other tundra-steppe fauna and flora fossils. These once extensive periglacial landscapes, developed over tens of millennia in unglaciated regions where late Pleistocene syngenetic permafrost expanded, and degraded on a large scale during the latest Pleistocene and Holocene warming. This period of rapid thaw transformed these areas into lake-rich thermokarst (thaw) landscapes, while extensive continental shelf areas were flooded by the postglacial transgression of Arctic seas. Ice-rich Yedoma deposits are very vulnerable to climate warming, which leads to different landscape changes such as surface subsidence, thermokarst, thermoerosion, deepening of the active layer, as well as remobilization of buried freeze locked organic matter and its contribution to greenhouse gases fluxes.