Three-dimensional geo-electrical structure in Juncalito geothermal prospect, northern Chile

Abstract

Magnetotelluric (MT) data were recorded to investigate a geothermal prospect in northern Chile. The exploration area is located in the Atacama region, at the southern edge of the Chilean Altiplano, at an altitude of similar to 4100 masl. This area belongs to the southern end of the Central Volcanic Zone (CVZ), a segment of the Andean Volcanic Belt associated with the oblique subduction of the Nazca plate beneath the South American plate. In the surveyed area of 19 MT sites, a two-dimensional geometry and an almost N-S geo-electric strike angle were obtained. A 3-D inversion was carried out and the obtained resistivity model shows a low resistivity layer (<10 Omega m) thicker westward of the profile. This result agrees with the classic pattern of the geo-electric structure in a geothermal system with potential (Anderson et al., 2000; Spichak and Manzella, 2009). The results from these magnetotelluric measurements were compared with different geophysical and geological information gathered in this area, helping to understand the geoelectrical structure obtained by magnetotellurics and to characterize this geothermal prospect. Different possible scenarios, given the available data, are shown.