The Domuyo volcanic complex (Neuquén Province, Argentina) hosts one of the most promising geothermal systems of Patagonia, giving rise to thermal manifestations discharging hot and Cl-rich fluids. This study reports a complete geochemical dataset of gas and water samples collected in three years (2013, 2014 and 2015) from the main fluid discharges of this area. The chemical and isotopic composition (?D-HO and ?O-HO) of waters indicates that rainwater and snow melting are the primary recharge of a hydrothermal reservoir located at relative shallow depth (400-600 m) possibly connected to a second deeper (2-3 km) reservoir. Reactive magmatic gases are completely scrubbed by the hydrothermal aquifer(s), whereas interaction of meteoric waters at the surface causes a significant air contamination and dilution of the fluid discharges located along the creeks at the foothill of the Cerro Domuyo edifice. Thermal discharges located at relatively high altitude (~ 3150 m a.s.l.), namely Bramadora, are less affected by this process, as also shown by their relatively high R/Ra values (up to 6.91) pointing to the occurrence of an actively degassing magma batch located at an unknown depth. Gas and solute geothermometry suggests equilibrium temperatures up to 220-240 °C likely referred to the shallower hydrothermal reservoir. These results, confirming the promising indications of the preliminary surveys carried out in the 1980?s, provide useful information for a reliable estimation of the geothermal potential of this extinct volcanic system, although a detailed geophysical measurements is required for the correct estimation of depth and dimensions of the fluid reservoir(s).
The hydrothermal system of the Domuyo volcanic complex (Argentina): A conceptual model based on new geochemical and isotopic evidences
Tassi F;Vaselli O;
2016
Abstract
The Domuyo volcanic complex (Neuquén Province, Argentina) hosts one of the most promising geothermal systems of Patagonia, giving rise to thermal manifestations discharging hot and Cl-rich fluids. This study reports a complete geochemical dataset of gas and water samples collected in three years (2013, 2014 and 2015) from the main fluid discharges of this area. The chemical and isotopic composition (?D-HO and ?O-HO) of waters indicates that rainwater and snow melting are the primary recharge of a hydrothermal reservoir located at relative shallow depth (400-600 m) possibly connected to a second deeper (2-3 km) reservoir. Reactive magmatic gases are completely scrubbed by the hydrothermal aquifer(s), whereas interaction of meteoric waters at the surface causes a significant air contamination and dilution of the fluid discharges located along the creeks at the foothill of the Cerro Domuyo edifice. Thermal discharges located at relatively high altitude (~ 3150 m a.s.l.), namely Bramadora, are less affected by this process, as also shown by their relatively high R/Ra values (up to 6.91) pointing to the occurrence of an actively degassing magma batch located at an unknown depth. Gas and solute geothermometry suggests equilibrium temperatures up to 220-240 °C likely referred to the shallower hydrothermal reservoir. These results, confirming the promising indications of the preliminary surveys carried out in the 1980?s, provide useful information for a reliable estimation of the geothermal potential of this extinct volcanic system, although a detailed geophysical measurements is required for the correct estimation of depth and dimensions of the fluid reservoir(s).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
