Socompa Geothermal Prospect. Report on Water Geochemistry

Abstract

This report regard the elaboration and interpretation of the results of chemical and isotopic analyses carried out on water samples collected from cold and thermal springs in the Socompa Geothermal Prospect (SGP), Salta Province (Argentina). Sample collection was carried out in a field campaign that took place between April 20th-25th , 2018. In the SGP just a single geochemical exploration study was performed (Galliski et al., 1987), but geochemical data for thermal waters collected seems to be disappeared or unavailable. Therefore, in order to get more information regarding the origin and evolution of thermal waters circulating in this area: - particular attention was addressed to the identification and sampling of cold and fresh waters from springs considered suitable to study the probable source areas (also sampled very far from the SGP, as for samples SO14, SO15 and SO16). These samples were included only in the elaboration of stable isotopic data, since their chemistry is governed by physico-chemical processes active in different geological context (far from SGP) and it is not representative of the local conditions present in the SGP. Conversely, the isotope composition of these waters could be useful for better understanding of the evolution of waters that feed the local thermal circuits; - the geochemical investigation was enlarged in the Salar of Llullaillaco (located ≈35Km S-SW to the Socompa Volcano), in which some thermal/warm springs were previously identified; - some previous data regarding samples from rain and surface water collected in the closed basins of the Atacama Desert (Northern Chile – Alpers and Whittemore, 1990) were included in the elaboration (even if just isotopic composition was analyzed).