Factors and Processes of Salt Lake Formation on Baikal Shore

Abstract

The article considers the conditions under which the water resources and chemistry are forming in the mineral Bormashovoe Lake, which lies on the Svyatoi Nos Peninsula on the eastern coast of Lake Baikal. The study was focused on water and free gas, which releases from bottom deposits and lakes in the Svyatoi Nos Peninsula. The results represent the analysis of water samples taken in ice-free and ice periods and studied to determine a wide range of chemical elements by up-to-date methods. The geological conditions existing in the region are considered. It is found that the rocks in the area near the lake are represented by eluvial deposits that have formed at intensive physical and, to a lesser extent, chemical weathering of granites. The recharge of the lake is shown to be mostly due to the discharge of fracture-vein and subsoil water, which form the specific geochemical pattern of lake water. In winter, the decomposition of organic residues of bottom sediments causes a change in the physicochemical conditions in lake water and increases its content of hydrocarbonate ion, calcium, magnesium, and rare-earth elements. Factor analysis was used to identify associations of elements which form under the effect of discharge of deep fracture-vein water, unconfined water enriched by decomposition products of rocks that had suffered the stage of frost weathering and lake water saturation by carbon dioxide in winter. Thermodynamic modeling showed that equilibrium exists in the lake with respect to calcite and dolomite, and the precipitation of carbonate minerals causes the accumulation of sodium and hydrocarbonate ion in water, making it soda water.