ПАЛЕОГЕОГРАФИЯ САРТАНСКОГО ОЛЕДЕНЕНИЯ ПАТОМСКОГО И СЕВЕРО-БАЙКАЛЬСКОГО НАГОРИЙ

Abstract

The article presents the results of the reconstruction of the spatial boundaries and parameters of glaciers for the isolated mountain structures of the Patomsky and North Baikal uplands in the era of the Last Glaciation (MIS 2) with the construction of a paleogeographic map. The object of this study is the dynamics of exogenous processes during the development of the permafrost zone in Eastern Siberia. The subject of research is the glacial relief forms of the Late Neopleistocene of the Patomsky and North Baikal uplands. The comparative, descriptive, cartographic research methods, methods of observation and actualism have been used. Based on the interpretation of aerial and satellite images, the identification of typomorphic glaciers with the maximum number of preserved destructive and accumulative glaciogenic forms, a depression of the snow boundary was established, which at that time was at the level of 2000…2100 m. The features of the lower boundary deformations of the chionosphere were revealed. Its deepest minimum is noted on the northwestern edge of the considered territory. The greatest decrease in relation to the paleoclimatic snow boundary, which extended to an altitude of 1600…1700 m, was 600…700 m. The positive extremum was confined to the central part of the Patom upland and exceeded the paleoclimatic snow line by 50…100 m. Anomalous extremes at that time period are due to global climatic, regional orographic and local (slope exposure) causes. It has been determined that in terms of morphology, glaciation of the territories under consideration is mountain-valley and reticulate with several sections of mountain-cover, confined to the flattened surfaces of the summit belt of mountain structures. According to the difference between the ice surface isolines and the valley bottom in the cross section, the thickness of the glacier was specified, and could reach 400…600 m. When searching for alluvial occurrences and gold deposits, as well as when sampling placer flows and secondary geochemical halos, it is recommended to orient prospecting in the direction of movement of ice masses. The new paleogeographic data obtained will increase the possibilities of more efficient mapping of Quaternary sediments within the North Baikal and Patom uplands and the identification of specific sections of river valleys in this area, favourable for placer formation