Geophysical imaging of fluid circulation and its relation with the structural system of Cerritos Colorados geothermal field, La Primavera caldera (Mexico)
La Primavera volcanic caldera was formed 95 ky ago producing peralkaline volcanism. The intra-caldera faults are a consequence of the uplift as a result of the new magma accumulation. This accumulation below the caldera structure was responsible for the caldera floor uplift, post-caldera volcanism,...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2019 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/377835 |
| Acceso en línea: | http://hdl.handle.net/10261/377835 |
| Access Level: | acceso abierto |
| Palabra clave: | Geothermal field Geophysical surveys Hydrothermal system La Primavera volcanic caldera Cerritos Colorados |
| Sumario: | La Primavera volcanic caldera was formed 95 ky ago producing peralkaline volcanism. The intra-caldera faults are a consequence of the uplift as a result of the new magma accumulation. This accumulation below the caldera structure was responsible for the caldera floor uplift, post-caldera volcanism, and hydrothermal activity in the Cerritos Colorados geothermal field. Here, we present the results of geophysical investigations of shallow hydrothermal activity and its relation with the structural system in this geothermal field. We applied the self-potential method that combined with surface temperature measurements allowed to identify the main infiltration and ascending fluid zones in the area. Electrical resistivity tomography (ERT) was measured in two selected places. One ERT profile (1.2 km in length) was located in the P12 well area, and a 3D resistivity model was carried out on the Cerritos Colorados graben area. Combining these geophysical prospecting results with a detailed structural map, we identified the main degassing zones (i.e. fumaroles) that correspond to higher permeability areas located along normal and strike-slip faults described for the first time in this work. In addition, we recognized a large number of small convective zones at meter-scale with clear circulation paths (upflow and downflow) of hydrothermal fluids. Therefore, our data suggest that a strong structural control exists on the surface manifestations of the hydrothermal system limiting the lateral extension of fluids. This emphasizes the importance that old structural boundaries related to the intra-caldera tectonic structures have upon the way hydrothermal fluids move. |
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