Specificity of the chemical and mineralogical composition of salts in solonchak playas and lakes of the Kulunda steppe

The chemical composition of water in 44 lakes of the Kulunda steppe has been studied. It is shown that solute concentrations in different lakes vary from 1 to 390 g/l. Four chemical types of the water salinity—chloride, sulfate, chloride-sulfate with the presence of sodium bicarbonate, and sodic waters—are distinguished. The nature of the water alkalinity has been studied in 12 lakes. In the lakes with neutral chloride and sulfate salts, the total alkalinity does not exceed 16.56 meq/l. In the lakes with the presence of soda, it reaches 189 meq/l. In sodic waters, the total alkalinity varies from 600 to 1504.6 meq/l. In the latter case, the water alkalinity is conditioned by the presence of soda and borate salts. Salt minerals in the bottom sediments and in the salt crusts of solonchakous playas around the lakes are represented by halite, calcite, dolomite, and thenardite. In two salt crusts, the presence of soda and trona has been diagnosed.