The Isotopic Composition of Waters in Hydrothermal Deposits of the Eastern Ciscaucasus and Their Genetic Features

摘要

Study of the isotopic composition of hydrogen (δD) and oxygen (δ~(18)O) in water and other elements therein (e.g., carbon in methane and carbon dioxide, argon, and helium) provides insights into the genetic, thermal, and geotectonic constraints of the formation of geothermal waters. In terms of geotectonics, the Dagestan Piedmont, located at the southern geosynclinal flank of the Tersk-Caspian Depression, incorporates two foldbelts (the Dagestan Wedge and the southern Dagestan Piedmont). The Dagestan Piedmont is among the most geother-mally and seismically active regions of the Caucasus. This has important hydrogeological significance for the vertical migration of gases and fluids (in particular, hydrothermal solutions). The foothill zone is marked by a series of deep faults, including seismically active ones. Some of these faults (e.g., Sulak and Samur) are distinctly traced in the topography as zones with intense jointing, centers of ancient and present-day hydrothermal manifestations, mineral springs, and seismic activity.