Isotope Signature Of The Massive Ice Bodies On The Northeast Coast Of Chukotka Peninsula

Yurij K Vasil’Chuk,Alla С Vasil’Chuk,Nadine A Budantseva,Nina N Komova,Alexey A Maslakov

doi:10.24057/2071-9388-2021-020

Yurij K Vasil’Chuk, Alla С Vasil’Chuk + Show 3 more

Open Access

https://doi.org/10.24057/2071-9388-2021-020

Copy DOI

Abstract

The massive ice (MI) bodies are widespread phenomena on Chukotka coastal plains. Although they have been studying since 1930s, stable isotope method was applied for the ice beds quite recently. In this study cryostratigraphy and stable oxygen and hydrogen isotope composition of MI bodies on the extreme North-Eastern Chukotka (near Lavrentiya settlement and Koolen’ lake) have been studied in detail. It was concluded that studied MI bodies have intrasedimental origin and most likely are dated back to the Late Pleistocene age. Mean δ18O values range from –18.5 ‰ to –15 ‰ whereas mean δ2 H values range from –146‰ to –128 ‰ that is higher than expected for the Late Pleistocene ice bodies in this region, which most likely resulted from isotopic fractionation during freezing of water-saturated sediments in a closed system when forming ice became isotopically enriched compared with initial water. The analysis of co-isotope ratios for MI shows that initial water is mainly of meteoric origin (precipitation, water of lakes and taliks).

Highlights

Massive ice bodies represent thick, often bedded, and sometimes deformed layers of massive ground ice and icy sediment and are the most spectacular of ground-ice forms
For massive ice bodies of intra-sedimental origin the study of stable isotope composition may allow to establish the nature of initial water and the conditions of ice formation (Vasil’chuk 2012; Vasil’chuk & Murton 2016)
Chukotka Peninsula is the easternmost part of Siberia; it is washed by the Bering Sea from the south and southeast and by the Chukchi Sea from the north (Fig. 1)

Summary

Introduction

Massive ice bodies represent thick, often bedded, and sometimes deformed layers of massive ground ice and icy sediment and are the most spectacular of ground-ice forms. Massive ice bodies were described in west and east Siberia, Chukotka, Alaska and Yukon, the Tuktoyaktuk Coastlands, the Canadian Arctic Archipelago and Russian Arctic islands, China and the Antarctic. These icy bodies are important because of their origin and the light this may throw upon permafrost history and because of the thaw-settlement properties of terrain underlain by such bodies. The first is that it is intra-sedimental and formed largely of segregated ice supplemented by water-injection processes that give rise to intrusive ice. The second is that they are bodies of buried glacier ice, without a clear distinction being made between glacier ice derived from snow and sub-glacier regelation ice (French 2018). For massive ice bodies of intra-sedimental origin the study of stable isotope composition may allow to establish the nature of initial water and the conditions of ice formation (Vasil’chuk 2012; Vasil’chuk & Murton 2016)

Objectives

Methods

Results

Conclusion