Cryogenic transformation of soil solutions and the development of salt profiles in solonchaks of Mongolia according to the results of modeling

The behavior of soil solutions in seasonally freezing solonchaks of Mongolia is discussed on the basis of the results of simulation experiments with the use of the FREEZBRINE model of physicochemical equilibria. Data on the chemical composition of soil solutions in solonchaks of the Ekhiin-Gol oasis have been used for modeling. The freezing temperatures; the character of the changes in the composition of the unfrozen brine; and the temperatures and intensities of the precipitation of hydrohalite, mirabilite, calcite, gypsum, and other salts have been calculated. The results obtained in this study allow us to estimate the contribution of the winter period of the soil functioning to the development of the salt profile in the solonchaks. One of the consequences of the cryogenic transformation of soil solutions in these solonchaks is a predominance of the sulfate type of salinization.