New Isotope-Geochemical Data on the Thermal Waters of the Talskoe Deposit (Magadan Oblast)

In this paper, we summarize new chemical and isotopic data on thermal waters of the Talskoe deposit in the Magadan Oblast. The first data were obtained on the stable oxygen (delta O-18) and hydrogen (delta D) isotope composition of thermal and background waters, as well as on the oxygen (delta O-18) and carbon (delta C-13) isotope composition of hydrocarbonate ion for this largest exploited deposit of low-salinity alkaline nitric thermal waters in the region. The thermal water is fresh (M = 980 mg/L), alkaline (pH = 8.9), hydrocarbonate-chloride-sulfate sodium with a high content of fluorine (up to 17 mg/L) and silicic acid (up to 152 mg/L). The deposit is fed by atmospheric precipitation and shows no traces of melting the underground ice. The application of a sequential scheme for calculating the temperature of a deep reservoir allowed the temperature of water formation to be constrained at 108 degrees C, suggesting an input of fluids rich in potassium and sulfate ion.