Lithological and mineralogical characteristic of the bottom sediments in the areas of ice scouring in the south-western Kara Sea

Abstract

Sedimentary material sampled in the western Kara Sea both directly in the ice scours and on the background surfaces not disturbed by ice scouring has been studied. Based on the results of research of the physical properties and lithological and mineralogical features of bottom sediments in the ice scours, the bedding depth of the ice gouging impact boundary (ploughing contact) was identified. According to X-ray diffraction analysis of the 0.001 mm fraction, in the samples obtained below this boundary, in contrast to the overlying samples, chlorite has non-heat-resistant structure, which, together with the results of microscopic studies in thin sections, indicates its neoformation. The presence of secondary chlorite in near-surface conditions may be an indicator of the glaciodynamic impact (pressure) of iceberg keels on bottom sediments. The microstructures of the ice scour sediments differ both on the different polygons of the study area and within the same scour, depending on the location of the sampling point on the transverse profile of the morphosculpture.