Las aguas termales de Fitero (Navarra) y Arnedillo (Rioja). l. Análisis geoquímico de los estados de equilibrio-desequilibrio en las surgencias

Abstract

The analysis of the different chemical features between the thermal springs of Fitero (Navarra) and Amedillo (Rioja), and between those thermal waters and other non-thermal ones in this area, has completed the geochemical characterization of both thermal manifestations. This characterization appear to confirm the existence of mixture phenomena in Fitero (in low proportions) and the narrow compositional range between the thermal springs considered in Amedillo. Taken into account the different geochemical variations of the studied waters, we have related their compositional characters with circulation through different litologies. So, thermal waters are associated to evaporitic materials (Keuper facies) with more saline characters for the Arnedillo thermal waters. On the other hand, the speciation-solubility analysis with WATEQ4F (Ba1l et al., 1987) of the spring chemical compositions and the study of associated deposits have allowed to stablish the physicochemical state at spring condition, a previous stage to determinate the thermodynamic water-rock interactions in the reservoir, at depth.