MASSIVE ICE BODIES OF GROUND ORIGIN ON THE EASTERN COAST OF CHUKOTKA: AGE AND ISOTOPIC COMPOSITION

Vasil’chuk, Yu. K.¹, Budantseva, N. A.¹, Maslakov, A. A.¹, Tokarev, I. V.², Vasil’chuk, A. C.¹

¹ Lomonosov Moscow State University (Moscow, Russian Federation)
² Research Park of Saint-Petersburg State University (St.Petersburg, Russian Federation)

The article was received on October 22, 2024

Bibliographic description: Vasil’chuk Yu. K., Budantseva N. A., Maslakov A. A., Tokarev I. V., Vasil’chuk A. C. Massive ice bodies of ground origin on the eastern coast of Chukotka: age and isotopic composition. Arktika: ekologiya i ekonomika. [Arctic: Ecology and Economy], 2025, vol. 15, no. 1. (In Russian).

Abstract: The current climate warming in the eastern coastal area of Chukotka contributes to deeper seasonal thawing and activation of thermal erosional landslides, leading to the exposure of massive ice bodies. The thawing of exposed massive ice courses the coastline destruction and settlement infrastructure damage. The study of massive ice bodies on the eastern coast of Chukotka, including radiocarbon AMS dating and determination of ice isotopic composition, showed that most of the studied ice bodies were formed in the Late Pleistocene, between 22 and 27.5 thousand calibrated years ago. Relatively high values of the ice isotopic composition and significant variations of the δ18O values of up to 6‰, indicate a predominantly ground origin of massive ice bodies, the formation of which occurred during the freezing of water-saturated sediments in a closed system. The source for the massive ice formation could be water-saturated sediments of sub-lake taliks or supra-permafrost groundwater. However, it is possible that locally massive ice bodies or their peripheral parts could be formed as a result of burial of snow patches or floating ice in the Holocene that may be indicated by a fairly uniform distribution of isotope values and the similarity of isotopic composition of some massive ice bodies and Holocene ice wedges.

Keywords: Russian Arctic zone, massive ice, cryostratigraphy, radiocarbon age, stable isotopes, Chukotka, Late Pleistocene

Funding:  This research was supported by Russian Scientific Foundation, grant no. 23-17-00082 (cryogenetic, isotope and radiocarbon studies, data compilation). Partial isotope analysis was carried out at the Centre for X-ray Diffraction Studies, Research Park of Saint-Petersburg State University within the framework of the project AAAA19-119091190094-6.

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