The analysis of ground- ice characteristics can give numerous clues about the geomorphologic processes and the thermal conditions at the time when permafrost developed. Other hypotheses for the origin of massive ice include the burial of ice (e.g. In situ freezing of water in the ground by ice-segregation processes forms most of these icy bodies. Massive icy bodies are important components of permafrost geosystems. Glacier-derived permafrost ground ice, Bylot Island, NunavutĬoulombe, S. Further data on Yedoma thickness is contributed from boreholes and exposures reported in the scientific literature. The quantification of the Yedoma coverage is conducted by the digitization of geomorphological and Quaternary geological maps. Hence, we here synthesize data on the circum-Arctic and sub-Arctic distribution and thickness of Yedoma permafrost (see figure for the Yedoma domain) in the framework of an Action Group funded by the International Permafrost Association (IPA). Moreover, as a step beyond the objectives of this synthesis study, our coverage (see figure for the Yedoma domain) and thickness estimation will provide critical data to refine the Yedoma permafrost organic carbon inventory, which is assumed to have freeze-locked between 83Â☑2 and 129Â☓0 gigatonnes (Gt) of organic carbon. Therefore, a detailed assessment of the Yedoma deposit volume is of importance to estimate its potential future climate response. This could be of global significance for the climate warming, as increased permafrost thaw is likely to cause a positive feedback loop. When Yedoma deposits degrade, large amounts of sequestered organic carbon as well as other nutrients are released and become part of active biogeochemical cycling. Moreover, ice-rich permafrost deposits like Yedoma are especially prone to degradation triggered by climate changes or human activity. Because of fast incorporation of organic material into permafrost during formation, Yedoma deposits include low-decomposed organic matter. Accompanied by wedge- ice growth, the sedimentation process was driven by cold continental climatic and environmental conditions in unglaciated regions during the late Pleistocene, inducing the accumulation of the unique Yedoma permafrost deposits up to 50 meter thick. Vast portions of Arctic and sub-Arctic Siberia, Alaska and the Yukon Territory are covered by ice-rich silts that are penetrated by large ice wedges, resulting from syngenetic sedimentation and freezing. Ice-Rich Yedoma Permafrost: A Synthesis of Circum-Arctic Distribution and Thickness
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