TY  - JOUR
A1  - Lenz, Josefine
A1  - Grosse, Guido
A1  - Jones, Benjamin M.
A1  - Anthony, Katey M. Walter
A1  - Bobrov, Anatoly
A1  - Wulf, Sabine
A1  - Wetterich, Sebastian
T1  - Mid-Wisconsin to Holocene Permafrost and Landscape Dynamics based on a Drained Lake Basin Core from the Northern Seward Peninsula, Northwest Alaska
JF  - Permafrost and Periglacial Processes
N2  - Permafrost-related processes drive regional landscape dynamics in the Arctic terrestrial system. A better understanding of past periods indicative of permafrost degradation and aggradation is important for predicting the future response of Arctic landscapes to climate change. Here, we used a multi-proxy approach to analyse a4m long sediment core from a drained thermokarst lake basin on the northern Seward Peninsula in western Arctic Alaska (USA). Sedimentological, biogeochemical, geochronological, micropalaeontological (ostracoda, testate amoebae) and tephra analyses were used to determine the long-term environmental Early-Wisconsin to Holocene history preserved in our core for central Beringia. Yedoma accumulation dominated throughout the Early to Late-Wisconsin but was interrupted by wetland formation from 44.5 to 41.5ka BP. The latter was terminated by the deposition of 1m of volcanic tephra, most likely originating from the South Killeak Maar eruption at about 42ka BP. Yedoma deposition continued until 22.5ka BP and was followed by a depositional hiatus in the sediment core between 22.5 and 0.23ka BP. We interpret this hiatus as due to intense thermokarst activity in the areas surrounding the site, which served as a sediment source during the Late-Wisconsin to Holocene climate transition. The lake forming the modern basin on the upland initiated around 0.23ka BP and drained catastrophically in spring 2005. The present study emphasises that Arctic lake systems and periglacial landscapes are highly dynamic and that permafrost formation as well as degradation in central Beringia was controlled by regional to global climate patterns as well as by local disturbances. Copyright (c) 2015 John Wiley & Sons, Ltd.
KW  - Beringia
KW  - palaeoenvironmental reconstruction
KW  - thermokarst lake dynamics
KW  - cryostratigraphy
KW  - tephra
KW  - bioindicators
KW  - yedoma
Y1  - 2016
U6  - https://doi.org/10.1002/ppp.1848
SN  - 1045-6740
SN  - 1099-1530
VL  - 27
SP  - 56
EP  - 75
PB  - Wiley-Blackwell
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  -