Saline groundwaters in the hercynian granites (Chardon Mine, France): geochemical evidence for the salinity origin - GéoHydrosystèmes COntinentaux - EA6293 Accéder directement au contenu
Article Dans Une Revue Applied Geochemistry Année : 1999

Saline groundwaters in the hercynian granites (Chardon Mine, France): geochemical evidence for the salinity origin

Résumé

In this study, the chemical evolution of high Cl− Chardon mine groundwaters is modelled as a mixing between an oxidising recharge and an old marine component on which the water–rock interaction is superimposed. Chemical and isotopic similarities with saline Carnmenellis mine groundwaters are emphasised and a general comparison with other brines is discussed. The cation content of deep granitic groundwaters is indicative of the water–rock interaction. In the case of Chardon and Carnmenellis groundwaters, the high Na/Cl ratio can still be related to the contribution of a brine of sedimentary origin to the water salinity. The differences in the hydrochemistry related to their geological context only appears at the trace metals level. On the contrary, brines in plutonic rocks which exhibit a low Na/Cl ratio represent groundwaters having a residence time in the host rock, long enough to equilibrate with secondary aluminosilicates. In that case, the brine origin is difficult to assess if only based on the water cation content.

Domaines

Géochimie

Dates et versions

hal-02330947 , version 1 (24-10-2019)

Identifiants

Citer

Catherine Beaucaire, Nathalie Gassama, Nathalie Tresonne, Didier Louvat. Saline groundwaters in the hercynian granites (Chardon Mine, France): geochemical evidence for the salinity origin. Applied Geochemistry, 1999, 14 (1), pp.67-84. ⟨10.1016/S0883-2927(98)00034-1⟩. ⟨hal-02330947⟩

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