Рельеф, коррелятные отложения и палеогеография Ольской низменности (Северное Приохотье)

The basic features of the geological and geomorphological structure and paleogeography of the Ola Lowland surface are determined. A wide distribution of heterogeneous Quaternary continental sediments has been established, with the predominant Upper Pleistocene glacial formations, forming a loose cover on the slopes, in river valleys, and on the plains of intermountain depressions. In some places, the lowland surface was formed on Oligocene-Miocene sediments composing the lower part of the sedimentary mass. Separate areas are formed by subhorizontal surfaces of the eroded Late Mesozoic basement of the lowland (leveling surfaces), composed of effusive and intrusive rocks of the Early Cretaceous age. In the Late Pleistocene, two glaciations took place in the territory under consideration: the Zyryan and the Sartan. The former significantly affected the formation of the lowland relief while the latter left moraines only in the narrow strip at its northern boundary. Layers of the Early Holocene volcanic ash are marked in the soil horizon of the lowland.