The geochemistry of water and gas phases from high pCO2 sparkling springs within the northern Sikhote-Alin ridge region (Russian Far East)

Two types of cold CO2 rich groundwaters are located within the northern part of the Sikhote-Alin ridge: the first type is a Ca-Mg-HCO3 water with low TDS content (<= 1.7 g/l) and high concentrations of Fe2+, Mn2+, Ba2+, and SiO2, whilst the second type is a Na-HCO3 water with a high TDS content (approximate to 14 g/l) and elevated concentrations of Li+, B-tot, Sr2+, Br-, and I-. A notable feature of these waters is a predominance of CO2 in the gas phase (up to 99 vol. %) and low contents of other gases (CH4, N-2, O-2, etc.). The origins of both water types can be identified on the basis of water (delta D, delta O-18) and gas (delta C-13, He-3/He-4, He-4/Ne-20) isotopic compositions considered in the context of the geology and hydrology of the region.