Fuente de calor en el campo geotérmico de Cerro Prieto y su relación con la anomalía magnética Nuevo León, México

Abstract

The Cerro Prieto geothermal system located within the Salton Trough province is one of the northernmost of a serie of active hydrothermal systems found along the East Pacific Rise-San Andreas Fault zone plate boundary transition. Several models have been developed in an attempt to understand the tectonic process which creates the geothermal environment in the area. Among such models is the one of Goldstein et al., (1984) which used the magnetic data and some petrographic analysis available. They proposed that the so called Nuevo León magnetic anomaly is produced by a prismatic body located at 3.8 km of depth which is constituted by gabbros and peridotites. Using the magnetic data and combining with the new petrological results from rock samples collected in recent boreholes from the field, and based upon the calculated thermal gradient, we have modified the Goldstein et al. (1984) model. The Nuevo Leon magnetic anomaly is produced not by one body but by two located at different depths and with different dimensions. In the shallower one, the top is located at 4.5 km and its base at 7 km deep, this is slightly tilted to the north. In the second body, the upper part is at 5 km deep and the base at 8 km. Both of them are gabbros in composition. Considering the results obtained and based upon the thermal gradient, the mixing zone is located at 11 km depth and the mafic plutonic bodies are considered part of the thermal source in the area.