Evolución temporal de los procesos secundarios en el sistema geotermal de Caldas de Boí (Lérida)

Resumen

The Caldas de Bol geothermal system is associated with granitic materials of La Maladeta massif (Pyrenees of Lérida, Axial Zone). The main water pathways for water flow is the dense fracture network affecting the pluton, which has enhanced the development of the geothermal system. Differences in pH and temperature of the thermal waters have been reported, indicating that they are affected by secondary processes, like mixing with superficial waters, conductive cooling, and CO, contamination during uprise from the reservoir. The main goal of this work is the study of the time evolution of these processes from 1983 to 2003 in order to determine the stability of the system against external driving forces. For that purpose, geochemical modelling techniques have been applied, mainly speciation-solubility calculations (for some elements), and the simulation of the key secondary processes. Comparing modelling results with observed values we have been able to quantify the relative importance of each process as a function of time.