Quaternary Deposits of the Gydan Peninsula Coast of Western Siberia and their Сryogenic Structure

Pismeniuk, A.; Streletskaya, I.; Gusev, E.

Авторы: Pismeniuk A., Streletskaya I., Gusev E.
Сборник: International Conference “Solving the puzzles from Cryosphere” : Program, Abstracts : Pushchino, Russia, April 15–18, 2019
Тезисы
Год издания: 2019
Место издания: Москва
Первая страница: 207
Последняя страница: 208
Аннотация: Permafrost is the most sensitive part of environment under current climate change. To understand the processes involved in the permafrost degradation it is necessary to characterize its evolution. The data on spread, morphology and isotopic composition of the ground ice are the basis of paleoenvironmental reconstruction in the Arctic region. The fieldwork was conducted between 2008-2010 by MSU, the Earth Cryosphere Institute, and the All-Russia Scientific Research Institute for Geology and Mineral Resources of the World Ocean (VNIIOkeangeologia). The description of the geological and geocryological structure of two outcrops near Matyuisale factory (Gydan Bay) and Dorofeevskiy settlement (Yenisey gulf) was made. These results are partially published. Isotopic composition of syngenetic ice wedges was determined by Isotope Laboratory of Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam. The particle size distribution was analyzed in Lithology and Mineralogy Laboratory (VNIIOkeangeologia). Radiocarbon datings of the peat received in Geomorphology and Palaeogeography Laboratory of Polar Regions and the World Ocean (KÖPPENLab, Institute of Earth Sciences, St.Petersburg State University) survey confirmed the author's conclusions. The new data on isotopic and chemical composition of ground ice, texture and age of deposits were processed and paleoenvironmental reconstruction was made. Quaternary deposits were formed by the sequence of transgressions and regressions. The features of cryogenic structure help to specify paleoenvironmental reconstruction of the Late Pleistocene and the Holocene. The last regression (MIS-2) was accompanied by freezing, dry climate and generation of syngenetic PWI (polygonal wedge ice) on the land and drained shelf area. During the climatic optimum of the Holocene degradation of the Late Pleistocene ice wedges occurred at the Kara Sea coast and caused erosion and slope processes. After thawing of the Pleistocene PWI ice-ground-wedge casts were formed. Subsequent cooling in the Late Holocene caused freezing and formation of new generation of PWI. The Holocene ice wedges provide a smaller square lattice than the Pleistocene ice and occasionally they were infiltrated into ice-ground-wedge casts. According to the data by Oblogov et al. (2012) the Pleistocene PWI remains in the areas remote from the sea coast of Gydan Bay and Yenisey gulf. This differentiation is caused by hard thermal abrasion and heating effect of the Kara Sea. Late winter ice melting in Gydan bay blocks thermal abrasion and lowers temperature. That creates conditions for relict ice conservation in the steeps. This study was supported by a grant RFBR 18-05-60080.
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Quaternary Deposits of the Gydan Peninsula Coast of Western Siberia and their Сryogenic Structureтезисы доклада

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