Solubility and Hydration of Hypsoanhydrites

Abstract

Gypsum anhydrite rocks are widespread in the upper part of the Earth’s crust, according to G.A. Maksimovich (1962), the area occupied by exposed and buried gypsum and anhydrites is 7 million km2. The study of solubility, hydration of anhydrites, and dehydration of gypsum is an important task of karst science. In a natural environment, the conditions necessary for hydration may not always occur, and the process may be limited to one phase, i.e. dissolution. In 1983-1992, K.A.Gorbunova and I.I.Minkevich, employees of the Institute of Karst Science and Speleology of the Russian Geographical Society, conducted a long-term experiment on the solubility of gypsum and anhydrite. It is concluded that the data obtained on the absence of saturation deficiency does not mean the cessation of the processes of dissolution of gypsum and anhydrite, the process proceeds constantly, becoming more active in the spring and summer period. The process of hydration of anhydrite depends on the degree of its moisture, in the zone of constant moisture hydration occurs without increasing the volume of the rock. In conditions of insufficient moisture (aeration zone), hydration proceeds with an increase in volume, which leads to deformations of the overlying rocks