TY  - JOUR
A1  - Wetterich, Sebastian
A1  - Schirrmeiste, Lutz
A1  - Nazarova, Larisa B.
A1  - Palagushkina, Olga
A1  - Bobrov, Anatoly
A1  - Pogosyan, Lilit
A1  - Savelieva, Larisa
A1  - Syrykh, Liudmila
A1  - Matthes, Heidrun
A1  - Fritz, Michael
A1  - Günther, Frank
A1  - Opel, Thomas
A1  - Meyer, Hanno
T1  - Holocene thermokarst and pingo development in the Kolyma Lowland (NE Siberia)
JF  - Permafrost and Periglacial Processes
N2  - 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.
KW  - bioindicators
KW  - cryolithology
KW  - hydrochemistry
KW  - Khalerchinskaya tundra
KW  - stable water isotopes
Y1  - 2018
U6  - https://doi.org/10.1002/ppp.1979
SN  - 1045-6740
SN  - 1099-1530
VL  - 29
IS  - 3
SP  - 182
EP  - 198
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Wetterich, Sebastian
A1  - Rudaya, Natalia
A1  - Kuznetsov, Vladislav
A1  - Maksimov, Fedor
A1  - Opel, Thomas
A1  - Meyer, Hanno
A1  - Günther, Frank
A1  - Bobrov, Anatoly
A1  - Raschke, Elena
A1  - Zimmermann, Heike Hildegard
A1  - Strauss, Jens
A1  - Starikova, Anna
A1  - Fuchs, Margret
A1  - Schirrmeister, Lutz
T1  - Ice Complex formation on Bol'shoy Lyakhovsky Island (New Siberian Archipelago, East Siberian Arctic) since about 200 ka
JF  - Quaternary research : an interdisciplinary journal
N2  - Late Quaternary landscapes of unglaciated Beringia were largely shaped by ice-wedge polygon tundra. Ice Complex (IC) strata preserve such ancient polygon formations. Here we report on the Yukagir IC from Bol'shoy Lyakhovsky Island in northeastern Siberia and suggest that new radioisotope disequilibria (230Th/U) dates of the Yukagir IC peat confirm its formation during the Marine Oxygen Isotope Stage (MIS) 7a–c interglacial period. The preservation of the ice-rich Yukagir IC proves its resilience to last interglacial and late glacial–Holocene warming. This study compares the Yukagir IC to IC strata of MIS 5, MIS 3, and MIS 2 ages exposed on Bol'shoy Lyakhovsky Island. Besides high intrasedimental ice content and syngenetic ice wedges intersecting silts, sandy silts, the Yukagir IC is characterized by high organic matter (OM) accumulation and low OM decomposition of a distinctive Drepanocladus moss-peat. The Yukagir IC pollen data reveal grass-shrub-moss tundra indicating rather wet summer conditions similar to modern ones. The stable isotope composition of Yukagir IC wedge ice is similar to those of the MIS 5 and MIS 3 ICs pointing to similar atmospheric moisture generation and transport patterns in winter. IC data from glacial and interglacial periods provide insights into permafrost and climate dynamics since about 200 ka.
KW  - Cryostratigraphy
KW  - Ice wedges
KW  - Stable isotopes
KW  - Pollen
KW  - Radioisotope disequilibria dating
KW  - Beringia
Y1  - 2019
U6  - https://doi.org/10.1017/qua.2019.6
SN  - 0033-5894
SN  - 1096-0287
VL  - 92
IS  - 2
SP  - 530
EP  - 548
PB  - Cambridge Univ. Press
CY  - New York
ER  -