Holocene thermokarst and pingo development in the Kolyma Lowland (NE Siberia)

Abstract Ground ice and sedimentary records of a pingo exposure reveal insights into Holocene permafrost, landscape and climate dynamics. Early to mid‐Holocene thermokarst lake deposits contain rich floral and faunal paleoassemblages, which indicate lake shrinkage and decreasing summer temperatures...

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Bibliographic Details
Published in:Permafrost and Periglacial Processes
Main Authors: Wetterich, Sebastian, Schirrmeister, Lutz, Nazarova, Larisa, Palagushkina, Olga, Bobrov, Anatoly, Pogosyan, Lilit, Savelieva, Larisa, Syrykh, Liudmila, Matthes, Heidrun, Fritz, Michael, Günther, Frank, Opel, Thomas, Meyer, Hanno
Other Authors: Bundesministerium für Bildung und Forschung, Deutsche Forschungsgemeinschaft, Russian Foundation for Basic Research, Russian Science Foundation, Saint Petersburg State University
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2018
Subjects:
Ice
Online Access:http://dx.doi.org/10.1002/ppp.1979
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fppp.1979
https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.1979
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Summary:Abstract Ground ice and sedimentary records of a pingo exposure reveal insights into Holocene permafrost, landscape and climate dynamics. Early to mid‐Holocene thermokarst lake deposits contain rich floral and faunal paleoassemblages, which indicate lake shrinkage and decreasing summer temperatures (chironomid‐based T July ) from 10.5 to 3.5 cal kyr BP with the warmest period between 10.5 and 8 cal kyr BP. Talik refreezing and pingo growth started about 3.5 cal kyr BP after disappearance of the lake. The isotopic composition of the pingo ice (δ 18 O − 17.1 ± 0.6‰, δD −144.5 ± 3.4‰, slope 5.85, deuterium excess −7.7± 1.5‰) point to the initial stage of closed‐system freezing captured in the record. A differing isotopic composition within the massive ice body was found (δ 18 O − 21.3 ± 1.4‰, δD −165 ± 11.5‰, slope 8.13, deuterium excess 4.9± 3.2‰), probably related to the infill of dilation cracks by surface water with quasi‐meteoric signature. Currently inactive syngenetic ice wedges formed in the thermokarst basin after lake drainage. The pingo preserves traces of permafrost response to climate variations in terms of ground‐ice degradation (thermokarst) during the early and mid‐Holocene, and aggradation (wedge‐ice and pingo‐ice growth) during the late Holocene.