New geochemical and isotopic insights to evaluate the geothermal resource of the hydrothermal system of Rosario de la Frontera (Salta, northern Argentina)

Cap rock efficiency of geothermal systems in fold-and-thrust belts: Evidence from paleo-thermal and structural analyses in Rosario de La Frontera geothermal area (NW Argentina)

“…In this case, the occurrence of long-range ordered mixed layer I-S indicates a temperature of at least 165 °C (Środoń, 1999) as a result of interaction of high temperature geothermal fluids circulating in highly fractured rocks. In addition, fluid inclusions analyses on calcite extensional veins of highly fractured rocks, indicate an entrapment temperature of about 115 °C consistent with the present-day temperature of thermal fluids at depths of 2,000 m that are in the range of 100-130 °C (Seggiaro et al, 1995;Chiodi et al, 2015). These paleofluid temperatures are higher than those currently measured at surface (71-81 °C, Fig.3) in thermal springs of the Hotel Termas area where a fluid mixing with shallow depth aquifer can be neglected .…”

“…3 Seggiaro et al, 1995;Pesce and Miranda, 2003;Invernizzi et al, 2014;Chiodi et al, 2015). At depths, reservoir rocks are fractured sandstones of the Cretaceous syn-rift deposits (Pirgua Subgroup) and cap rocks are low permeability post-rift and syn-orogenic deposits (Balbuena and Santa Bárbara Subgroups, and Metán Subgroup respectively; Moreno Espelta et al, 1975;Seggiaro et al, 1995Seggiaro et al, , 2015Invernizzi et al, 2014;Maffucci et al, 2015).…”

“…The conceptual model of fluid circulation consists of two aquifers developed at different depths and detected on the basis of geochemical, hydrogeological (Invernizzi et al, 2014;Chiodi et al, 2015) and audio-magnetotelluric (Barcelona et al, 2013) investigations. The deepest hydrothermal reservoir, hosted within the Cretaceous Pirgua Subgroup deposits, is mainly recharged by meteoric water (Invernizzi et al, 2014;Chiodi et al, 2015;Seggiaro et al, 2015) and shows a Na-HCO 3 composition with significant contributions of crustal CO 2 and He from mantle degassing . The uprising thermal fluids mix with a relatively high salinity Na-Cl dominated shallower aquifer produced by the interaction of meteoric water with evaporite deposits of the Anta Fm .…”

“…2a). They record surface temperatures up to 90°C (Pesce and Miranda 2003;Chiodi et al 2012aChiodi et al , 2012bChiodi et al , 2015Fig. 3a).…”

“…best fit of paleo-thermal data (Seggiaro et al, 1995(Seggiaro et al, , 2015Di Paolo et al, 2012;Invernizzi et al, 2014;Chiodi et al, 2015).…”