Comparative Analysis of Mineral Assemblages in Bottom Sediments from Buor-Khaya Bay

Abstract

According to the results of an analysis of 99 samples of bottom sediments and submarine permafrost from boreholes 1D-14, 3D-14, and 1D-15 drilled in Buor-Khaya Bay, differences in their mineral composition due to paleogeographic factors, namely, Late Quaternary changes in climate and sea level, as well as regional hydrodynamics are shown. The basis of the light fraction of minerals was quartz and feldspar (mainly plagioclase), found as grains of various dimensions and degree of sorting, as well as fine grains. To a lesser extent, chlorite, kaolinite, and serpentine have been noted; illite and smectite are rare. Forty-two accessory minerals were identified in the heavy fraction (average yield 0.95%) concentrated in fine-grained sands. It mainly consists of pyroxene, amphibole, carbonatite, epidote, zoisite, magnetite, mica, garnet, limonite, titanite, leucoxene, and ilmenite. Rutile, kyanite, sillimanite, zircon, tourmaline, apatite, and staurolite were found in smaller quantities. In the studied strata, plant remnants and carbonlike particles (kerogen) have been found, the contribution of which exceeds 5% by weight in a number of samples. The results of the study allowed the conclusion that the basis of the petrofund of the studied deposits are most likely sedimentary rocks of the Kharaulakh ridge of the Verkhoyansk Mountain system (sandstone, siltstone, and mudstone). The presence of characteristic accessory minerals in the sediments marks the unloading of igneous and metamorphic rocks, but their contribution is subordinate. They probably also include rocks of the Verkhoyansk Complex, common near Tiksi.