The origin and chemical composition of Carpathians chloride CO2-rich waters in the light of stable chlorine isotope studies (37Cl and 35Cl)

Abstract

Investigations into chloride CO₂-rich water occurring in the Polish and Slovakian Carpathians were carried out to gain a better understanding of the Cl^– sources. The primary Cl^– concentration in sea water, processes accompanying diagenesis, together with water-rock-gas interactions, have undoubtedly influenced the present content of chlorides. The Cl^–- concentrations in the waters analysed vary from 35.5 to 4148.3 mg/l, lower than in sea water, with a mean ~19000 mg/l. The measured δ³⁷Cl values range from –1.15 to –0.26‰, below the typical sea water value of 0‰. It might be concluded that the chemical and isotopic composition of these waters are the result of reactions during diagenesis (e.g., ion exchange or diffusion through low-permeability clay layers) as well as meteoric water influx.