CONICET | Buscador de Institutos y Recursos Humanos

The exploration of geothermal systems in Andean regions is a very important issue, because of the presence of thermal anomalies within the crust. It is associated with a recent volcanic features and evidences of geothermal activity. To explore those resources it is necessary a comprehensive multidisciplinary research (geological, hydrogeological, geochemical and geophysical) selecting techniques appropriate for geothermal studies. Three-dimensional MT studies contribute to the characterization of the electrical structure of geothermal reservoirs with higher accuracy and resolution.The geothermal volcanic area, Cerro Tuzgle ?Tocomar, approximately 160km East of the main volcanic arc, on the Calama Olacapato Toro Lineament, has a high geothermal potential. This area shows evidences of several geothermal manifestations, including active and fossil hot-springs and travertine deposits. The preliminary general conceptual model proposed, consists in a main reservoir located in fractured Ordovician basement at 0.8 ? 2km, and a secondary, small and more superficial reservoir within the Pirgua subgroup, about 100-200m deep. The main objective is to determine the geometry of the geothermal system finding electric structures which could be related to reservoirs and heat sources around Tuzgle and Tocomar volcanic area. Thirty sites were recorded at frequencies from 0.0001Hz to 0.1Hz in two surveys during 2014 and 2016. In the preliminary inversions, different parameters, components, rotation and error floor were applied to observe their effect on the model. A 3D inversion of magnetotelluric data has been performed using the ModEM code. Model analysis revealed a good correlation between the features of the geothermal field and resistivity distribution, showing shallow conductors that agree with the geothermal manifestations, deep elongated vertically conductors, and also high resistive zones showing the extension of the geothermal system.