Geochemical Anomalies of Frozen Ground due to Hydrocarbon Migration in West Siberian Cryolithozone

Anna Kurchatova,Victor Rogov,Natalia Taratunina

doi:10.3390/geosciences8120430

Anna Kurchatova, Victor Rogov + Show 1 more

Open Access

https://doi.org/10.3390/geosciences8120430

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Journal: Geosciences	Publication Date: Nov 22, 2018
Citations: 1	License type: CC BY 4.0

Affiliation: Skolkovo Institute of Science and Technology

Abstract

According to the study of frozen deposits in the territory south of the Taz Peninsula, geochemical processes are considered under the hydrocarbon migration from the lower productive complex. An analysis of the cryolithological structure of the frozen stratum was performed, and the composition of the gas and authigenic associations was studied. It was shown that the migration of gases is caused by shear deformations with the formation of cryogenic textures with the presence of gas-bearing ice crystallites on slip surfaces. It was found that the migration of hydrocarbons causes significant local changes in pH/Eh parameters in the frozen stratum and determines the micromosaic distribution of sulfate and iron reduction processes that lead to the formation (including microbiological processes) of various forms of iron: sulphides, carbonates and oxides.

Highlights

The problem of the emission of carbon dioxide and methane from the frozen stratum has been one of the most acute and controversial topics since the end of the last century, when the effect of the emission on the rise in the temperature of the atmosphere at high latitudes was shown
Deposits underlying the ice core of the frost mound were exposed by drilling, which are represented by diatom clays with inclusions of interlayers of more sandy material
The results of the surface geochemical survey in West Siberia show the widespread occurrence of hydrocarbon migration as the reservoir leaks through permafrost strata [17]

Summary

Introduction

The problem of the emission of carbon dioxide and methane from the frozen stratum has been one of the most acute and controversial topics since the end of the last century, when the effect of the emission on the rise in the temperature of the atmosphere at high latitudes was shown. Most of these studies are devoted to the calculation of organic carbon stocks buried in syncriogenic rocks [1]. Permafrost is still perceived as an impenetrable screen for gases [3,4] with a low activity of biochemical processes [5]

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Conclusion