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

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 (chironom...

Full description

Bibliographic Details
Published in:Permafrost and Periglacial Processes
Main Authors: Wetterich, Sebastian, Schirrmeiste, Lutz, Nazarova, Larisa B., Palagushkina, Olga, Bobrov, Anatoly, Pogosyan, Lilit, Savelieva, Larisa, Syrykh, Liudmila, Matthes, Heidrun, Fritz, Michael, Günther, Frank, Opel, Thomas, Meyer, Hanno
Format: Article in Journal/Newspaper
Language:English
Published: 2018
Subjects:
ddc:530
Institut für Physik und Astronomie
Kolyma
Talik
Ice
permafrost
Thermokarst
wedge*
Siberia
Online Access:https://publishup.uni-potsdam.de/opus4-ubp/frontdoor/index/index/docId/52618
https://doi.org/10.1002/ppp.1979
Description
Summary: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 (delta O-18 - 17.1 +/- 0.6 parts per thousand, delta D -144.5 +/- 3.4 parts per thousand, slope 5.85, deuterium excess -7.7 +/- 1.5 parts per thousand) point to the initial stage of closed-system freezing captured in the record. A differing isotopic composition within the massive ice body was found (delta O-18 - 21.3 +/- 1.4 parts per thousand, delta D -165 +/- 11.5 parts per thousand, slope 8.13, deuterium excess 4.9 +/- 3.2 parts per thousand), 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.

Similar Items