Geological and geochemical characterization of the Tai Pichín thermal area, Cuniputo Range, province of Córdoba

Abstract

Abstract: The thermal spring known as Tai Pichín is located in the Cuniputo range, Córdoba province, and has a spring temperature of 21 °C. This study presents the results of the geochemical and isotopic analysis of water samples, both from the Tai Pichín spring and from nearby surface water courses, which were used to characterize the fluids and develop a conceptual model for the geothermal system. The hydrothermal fluid has a Na+ - HCO3- composition and an estimated temperature of 87 °C at depth. This fluid would be hosted in the metamorphic basement of the La Falda Metamorphic Complex, and the main structures in the area would control its ascent. The isotopic data of water (δ18O y δ2H) suggest local meteoric recharge, with the Cuniputo range being the main recharge area. However, a more extensive circulation pathway is suggested, including the granite outcrop area of Capilla del Monte as a recharge zone. Meteoric water could reach depths of ~2 km, acquiring the estimated temperatures by geothermometers in a normal gradient area, thus establishing a possible heat source linked to the deep circulation of fluids through the structures. However, the existence of a shallower circulation circuit cannot be ruled out, where water attains high temperatures at depth due to radiogenic heat associated with the Capilla del Monte granite.