Origin of hotsprings near Villarrica volcano
Origin of hotsprings near Villarrica volcano
Authors
Bucarey Parra, Claudia
Authors
Date
Datos de publicación:
Temuco, Universidad Católica de Temuco, 2019
Keywords
Geoquímica - Aguas termales - Gas disuelto - Volcán Villarrica
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Abstract
El volcán Villarrica es uno de los volcanes más activos de la Zona Volcánica de Los Andes del Sur (SAVZ) y presenta varias manifestaciones termales en sus alrededores. Si bien existen numerosos estudios acerca de la composición y origen de las aguas termales de esta zona, no se ha podido establecer cuál es la influencia de la actividad volcánica en estas manifestaciones. La mayoría de las termas ubicadas cerca de la zona volcánica, entre las ciudades de Pucón y Curarrehue, fueron muestreadas entre los años 2012 y 2017. En este estudio, identificamos los procesos que afectan la composición de las aguas y que puedan explicar el origen y su naturaleza. Análisis químicos fueron realizados permanentemente, con el objetivo de describir la composición química de las aguas termales, y con esta información entender el comportamiento de las aguas en profundidad. Así mismo, se implementó por primera vez en esta zona de estudio, el análisis de gas disuelto en agua. Estas manifestaciones emergen directamente desde granitoides, depósitos volcanoclásticos, piroclásticos y fluviales. Los parámetros fisicoquímicos tales como: temperatura, pH y sólidos disueltos totales (TDS) fueron medidos in-situ. Nuestros resultados muestran que las temperaturas en un rango entre 29 y 87ºC son comunes en estas aguas mesotermales y los valores de pH permiten clasificar estos fluidos como neutros – alcalinos (pH=7.0 – 9.7). Las manifestaciones presentan concentraciones de iones en rangos bajos y moderados (TDS=76 – 656 mg/L). Las aguas y los gases disueltos fueron muestreados para analizar elementos mayores, trazas e isótopos (18O-D). Con estos datos, se observó una mezcla de procesos en los cuales las recargas meteóricas del sistema y su interacción en profundidad con gases magmáticos, son los principales mecanismos de generación de la termalidad de esta zona
The Villarrica volcano is one of the most active volcanoes of the Southern Andes Volcanic Zone (SAVZ) and has several thermal manifestations in their surroundings. Although there are numerous studies about the composition and origin of the thermal waters of this area, it has not been possible to establish which is the influence of volcanic activity in these manifestations. Most hotsprings located close to the Villarrica volcano, between Pucón and Curarrehue locations were sampled during 2012 and 2016. In this study, we identify the processes that affect the composition of the water that can explain the origin and its nature.Chemical analyzes were carried out permanently, with the objective of describing the chemical composition of the thermal waters, and with this information to understand the behavior of the waters in depth. Likewise, the analysis of gases dissolved in water was implemented for the first time in this area of study. This manifestation emerges directly from granitoides, volcanoclastic, pyroclastic and fluvial deposits. Physicochemical parameters such as: temperature, pH, and total dissolved solids (TDS) were measured in-situ. Our results showed that temperatures ranging between 29 – 87 °C, are common in these mesothermal waters, and pH allows to classify these fluids as neutral to alkaline waters (pH=7.0 to 9.7). Hot springs present low to moderate concentrations of ions (TDS= 76 to 656 mg/L). Water and dissolved gases were sampled to analyze main elements, traces and isotopes (18O – D). With these data, a mixture of processes was observed in which the meteoric recharges of the system and their deep interaction with magmatic gases are the main mechanisms of generation of the thermal manifestations of this zone
The Villarrica volcano is one of the most active volcanoes of the Southern Andes Volcanic Zone (SAVZ) and has several thermal manifestations in their surroundings. Although there are numerous studies about the composition and origin of the thermal waters of this area, it has not been possible to establish which is the influence of volcanic activity in these manifestations. Most hotsprings located close to the Villarrica volcano, between Pucón and Curarrehue locations were sampled during 2012 and 2016. In this study, we identify the processes that affect the composition of the water that can explain the origin and its nature.Chemical analyzes were carried out permanently, with the objective of describing the chemical composition of the thermal waters, and with this information to understand the behavior of the waters in depth. Likewise, the analysis of gases dissolved in water was implemented for the first time in this area of study. This manifestation emerges directly from granitoides, volcanoclastic, pyroclastic and fluvial deposits. Physicochemical parameters such as: temperature, pH, and total dissolved solids (TDS) were measured in-situ. Our results showed that temperatures ranging between 29 – 87 °C, are common in these mesothermal waters, and pH allows to classify these fluids as neutral to alkaline waters (pH=7.0 to 9.7). Hot springs present low to moderate concentrations of ions (TDS= 76 to 656 mg/L). Water and dissolved gases were sampled to analyze main elements, traces and isotopes (18O – D). With these data, a mixture of processes was observed in which the meteoric recharges of the system and their deep interaction with magmatic gases are the main mechanisms of generation of the thermal manifestations of this zone
Description
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