Current travertines precipitation related to artificial CO2 leakages from a natural reservoir (Gañuelas-Mazarrón Tertiary Basin, SE Spain)
In the framework of a natural CO reservoir with CO leakages as an analogue of a failed CO deep geological storage, the current precipitation of travertines and the associated upwelling of CO-rich saline groundwater were analysed. This natural analogue is located in the Gañuelas-Mazarrón Tertiary Bas...
| 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:10261/204980 |
| Acceso en línea: | http://hdl.handle.net/10261/204980 |
| Access Level: | acceso abierto |
| Palabra clave: | CO2 storage CO2 leakage Travertines Stable isotopes Betic Cordillera |
| Sumario: | In the framework of a natural CO reservoir with CO leakages as an analogue of a failed CO deep geological storage, the current precipitation of travertines and the associated upwelling of CO-rich saline groundwater were analysed. This natural analogue is located in the Gañuelas-Mazarrón Tertiary Basin (SE Spain). The study comprises of the chemistry of both groundwater and travertines, including stable isotopes, mineralogy and petrography of the travertines, all this performed after a review of the geology of the basin. In this sense, the basin gathers the main features of a safe natural CO reservoir in a deep saline aquifer sealed by a thick marl formation. The aquifer was artificially perturbed by the drilling of wells, inducing the travertines precipitation at these water discharge points. Groundwater is saline, slightly acid, oversaturated in aragonite and calcite and with significant concentrations of heavy elements, some of them toxic. From an isotopic viewpoint, the relative constant δC-DIC values suggest that carbon is mainly inorganic in origin with minor organic and mantle contributions. Travertines are basically composed of aragonite or calcite, their precipitation being controlled by a sudden CO degassing and minor biological activity. Their δC signatures indicate that carbon mainly has an inorganic origin, although some contribution of organic carbon must be considered as well. Furthermore, these carbonate deposits did not precipitate in isotopic equilibrium, as determined by δO values. Finally, it is suggested that the appearance of travertines along with their carbon isotopic signatures represent efficient tools for detecting CO leakages from any CO storage site. |
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