Chemical and Isotopic Composition of Water and Gas Phases from Mukhen Spa (Far East of Russia)

Abstract

This study presents new chemical and isotopic data on the two types of cold high pCO2 groundwaters located in the Mukhen deposit (Far East of Russia). The first type belongs to HCO3-Ca-Mg waters with a relatively low TDS (up to 1.7 g/l) and high concentrations of Fe2+, Mn2+, Ba2+, and SiO2. The second type is of HCO3-Na water with high TDS (up to 14 g/l) and elevated Li+, B, Sr2+, Br−, and I−. New isotopic data of water (δ18O, δD and 3H) and gas (δ13CTIC) phases along with a detailed geological and hydrogeological investigation of the study area allowed identifying genesis of both the mineral waters. The residence time of groundwaters were calculated as well. It was established that the origin of the high pCO2 groundwaters was caused by active faulting and CO2 venting in the subsurface zone.