FROZEN AND CRYOTIC GROUND IN THE BAYDARA BAY AREA
S.I. Rokos1, D.A. Kostin2, A.V. Tulapin1, S.N. Kulikov1, A.G. Dlugach1
1Arctic Marine Engineering-Geological Expeditions (AMIGE), Murmansk, Russia
2Murmansk State Technical University, Murmansk, Russia
Keywords: the Kara Sea, the Baydara Bay, permafrost, frozen ground, cooled soils, seasonally-frozen soils, subsea permafrost, soil temperature, a melting point temperature, a thermal cone penetration test, Quaternary deposits
Abstract
The purpose of this study is to establish the genesis and conditions of formation of different types of sediments in the permafrost area of Baydara Bay. Perennially and seasonally frozen and perennially and seasonally cryotic sediments have been identified on the basis of temperature measurements in core samples obtained during geotechnical drilling and thermal cone penetration tests along the profile crossing the bay. We suppose that permafrost was formed in this area in the course of epigenetic freezing during the Sartan regression. Seasonally frozen ground of the seafloor is subdivided into two types. The first type is characteristic of coastal shallows, where landfast ice contacts the seafloor. The second type is formed in the seaward part of the water area during the cold season, when the temperature of near-bottom seawater drops to values below the freezing point. Perennially cryotic (but unfrozen) ground is formed below the depth of the 0° isotherm traced during the warm season. Seasonally cryotic ground above this isotherm has above-zero temperatures in the warm season. In the winter season, under the impact of subzero temperatures of seafloor water, it is transformed into the cryotic or seasonally frozen state.
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