Reconstruction of solution chemistry evolution based on the sedimentary record of salt lakes in the Olkhon region

Using data on the chemical composition of lake waters in the Olkhon region, we calculated the under- and oversaturation of modern chloride solutions of Lake Tsagan-Tyrm. These data are a basis for the determination of the composition of suspension and bottom sediments. The thermodynamically calculated solubility of carbonates (inverse problem) discovered in the evaporite lacustrine sediments gave an insight into the main regularities of the chemical evolution of ancient brines and the formation conditions of various magnesian calcites. The calculations confirmed that an increase in solution mineralization leads to the deposition of high-Mg calcites, which is also observed in the bottom sediments of other lakes under climate aridization and temperature decrease.