Mountain Yangan-Tau is known for its extraordinary thermal phenomenon: from its bowels continually stand hot steam and gases, although this area is at a great distance from the areas of contemporary and relatively recent volcanic activity. The first scientific description of this phenomenon was made by Academician P.S. Pallas in the summer of 1770. As a result of numerous subsequent studies, subsoil mountains warmed by more than 300 degrees and heat reserves are significant. According to one hypothesis (G.V. Vakhrushev) heat is produced by the oxidation of bitumen contained in marl artinskian floor. This reaction is maintained inorganic catalysts contained in the same strata. The heating zone is located mainly on a depth of 60-80 m from the surface. At the foot of Yangan-Tau come to the surface fresh and brackish springs of bicarbonate-calcium sulfate and calcium-sodium, sulfur has a number of sources.