Chlorine Geochemical and Isotopic (37Cl/35Cl) Signatures of CO2-Rich Mineral Waters (N-Portugal): Revisited
The CO2-rich mineral waters from Vilarelho da Raia, Chaves, Vidago and Pedras Salgadas region (N-Portugal) were analyzed for 37Cl/35Cl, Cl and other major elements. Local rain and shallow cold dilute waters were also studied. The main objective of this study was to use Cl geochemical signatures together with Cl isotope geochemistry to improve our knowledge on the origin of Cl in the hot (≈76 °C) and cold (≈16 °C) Na-HCO3-CO2-rich mineral waters that discharge in the region. Chlorine, a good tracer of water-rock interaction, presents a strong correlation with sodium (dominant cation) indicating that Cl− present in the mineral waters originates from water-granitic rock interaction. δ37Cl isotope signatures indicate that i) 37Cl/35Cl in the studied mineral waters can also be explained by water-granitic rock interaction and ii) the contribution of a deep-seated (upper-mantle) Cl component should not be excluded.
KeywordsGeochemistry Isotopes Sources of Cl CO2-rich mineral waters N-Portugal
This work was funded by the PRAXIS Project “FLUMIRE” under the Contract No. C/CTE/11004/98. CERENA/IST acknowledges the FCT (the Portuguese Science and Technology Foundation) support through the UID/ECI/04028/2013 Project and C2TN/IST author gratefully acknowledge the FCT support through the UID/Multi/04349/2013 Project.
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