Mineral deposits and underground waters of the caves of the Surkhantau Range (Uzbekistan)
E.P. BAZAROVA1, O.I. KADEBSKAYA2, E.A. TSURIKHIN3, A.M. KONONOV4
1Institute of the Earth’s Crust, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
2Mining Institute, Ural Branch, Russian Academy of Sciences, Perm, Russia
3Ural Branch of the Russian Research Institute of Fisheries and Oceanography, Ekaterinburg, Russia
4Irkutsk National Research Technical University, Irkutsk, Russia
Keywords: cave, minerals, groundwater, isotopy, Gissar Range
Abstract
The morphology, chemical and isotopic composition of mineral deposits of three caves in the high-mountain region of the Surkhantau Range, located in the southeast of Uzbekistan, have been studied for the first time. The range is part of the southwestern spurs of the Gissar Range, which belongs to the Gissar-Alai mountain system of the Southern Tien Shan. Four types of mineral deposits have been identified in the caves under consideration, the most significant of which are water-chemogenic formations. These deposits, morphologically represented by aggregates of gravitational, subaqueous, corallite-crystallictite crusts, cave powder and fibrous formations, are composed mainly of calcite with inclusions of fluorapatite, barite, magnetite, goethite, rutile, plagioclase, epidote and quartz. The deposits from the entrance part of the Vishnevsky Cave are distinguished by an increase in d13С with almost identical d18О values, which indicates negative temperatures. The data on the composition of groundwater are presented, and the conditions of their formation during speleolithogenesis are described based on hydrogeochemical and isotope studies. The isotopic composition of karst waters is indicative of the predominance of winter snow feeding. Large calcite aggregates and a thick layer of loose sediments in underground cavities provide evidence of the formation of caves in warm and humid climates by abundant watercourses with a feeding area in non-karst sandstones, which are currently almost destroyed by erosion. At present, the development of underground cavities continues in the bottom parts due to the activity of groundwater and in the entrance parts due to landslide processes.
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