Hydrodynamic Conditions of Sedimentation in the High-Mountain Lake Sagan-Nur (Eastern Sayan) on the Basis of Rock-magnetic Data

The results of rock-magnetic study of the Sagan-Nur-2021-I core from the bottom sediments of the glacial lake Sagan-Nur are presented. The lake is located in the central part of the Oka Plateau, Eastern Sayan Mountains. The hydrodynamics of Sagan-Nur Lake is reconstructed on the basis of the anisotropy of the magnetic susceptibility and the scalar magnetic parameters. It has been shown that abrupt change in the hydrodynamic settings in the lake is associated with the inflow of various volumes of melt waters into its basin as a result of degradation of both surface and subsurface glaciation. An age model was based on seven AMS 14C-dates. Taking into consideration this model, the changes in the hydrodynamic and sedimentation conditions in Sagan-Nur Lake have been reconstructed for the last 14 000 years in terms of climatic fluctuations during the Late Pleistocene–Holocene.