New data on Quaternary deposits of the Pechora-Vychegda-Kama watershed

Research subject. Quaternary deposits in six wells. Two wells (No. 20830 and 20831) are located on the upper Pechora, and four wells (No. 20837, 20839, 20840 and 20841) are located in the upper reaches of the Vychegda River. Aim. Identification of the geological structure of Quaternary deposits in the research area and carrying out their facies-genetic division. Methods. The sediments were studied by granulometric and mineralogical methods, and in samples from well No. 20841, spores and pollen were isolated and palynological spectra were studied. Results. The facies-genetic division of Quaternary deposits was carried out based on changes in the structural features in the sections. The mineral composition of the heavy fraction of sediments is characterized by increased contents of ilmenite (up to 45%) and epidote (up to 38%), which are characteristic minerals of the North-Eastern terrigenous-mineralogical province, including Novaya Zemlya, Pai-Khoi and the Polar and Subpolar Urals. As a result of the palynological study of alluvial and lacustrine sediments in the well No. 20841 three spore-pollen complexes were identified. Conclusions. Alluvial, lacustrine (limny) and glacial deposits (moraines and fluvioglacial sediments) were identified in the well sections. The mineral composition of the heavy fraction indicates the participation of Ural igneous and metamorphic rocks in their formation, and the supply of minerals from the Kama, where Pliocene deposits are widely developed, seems very doubtful. Two palynological complexes were formed in the Middle Neopleistocene during the Rodionovian (Shklovian) interglacial, probably, and the third, characterizing rather harsh climatic conditions, in the initial phase of the Byzovian (Leningrad) megainterstadial of the Late Neopleistocene.

granulometric composition, mineral composition, palynology, alluvium, limnium, moraine, fluvioglacial deposits