Maria P. Asta , Luis F. Auque , Maria J. Gimeno , Cristina Reyes-Carmona , Aita Gantenbein , Jesús Rosino , Antonio Delgado-Huertas
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引用次数: 0
Abstract
Geothermometrical calculations in thermal systems are often limited by the presence of secondary processes that modify the chemistry of the deep reservoir fluid during the ascent to the surface (e.g., mixing, degasification). The effect of secondary processes can be avoided by applying some techniques to reconstruct the chemical equilibrium at depth and the fluid original composition. However, the reconstruction of thermal waters mixed with cold surficial waters is complicated when the dilution factors are unknown. For that case, here, we propose to use an approach consisting of the simulation of a concentration process that removed different amounts of water from the thermal solutions until the equilibrium temperatures of anhydrite and quartz converge for the waters affected by mixing in unknown proportions. Using classical geothermometers and geothermometrical modeling, including the water removal process and CO2 degasification, a temperature range of 78 ± 9 °C at depth has been established for the Sierra Elvira geothermal system whose waters are in chemical equilibrium with respect to calcite, dolomite, anhydrite, quartz, illite, pyrophyllite and beidellite-K. The good agreement in the temperatures obtained for the different thermal fluids of the system suggests a common reservoir for all of them. The methodology used in this study can be applied to other geothermal systems in carbonate rocks affected by mixing.
期刊介绍:
Journal of Geochemical Exploration is mostly dedicated to publication of original studies in exploration and environmental geochemistry and related topics.
Contributions considered of prevalent interest for the journal include researches based on the application of innovative methods to:
define the genesis and the evolution of mineral deposits including transfer of elements in large-scale mineralized areas.
analyze complex systems at the boundaries between bio-geochemistry, metal transport and mineral accumulation.
evaluate effects of historical mining activities on the surface environment.
trace pollutant sources and define their fate and transport models in the near-surface and surface environments involving solid, fluid and aerial matrices.
assess and quantify natural and technogenic radioactivity in the environment.
determine geochemical anomalies and set baseline reference values using compositional data analysis, multivariate statistics and geo-spatial analysis.
assess the impacts of anthropogenic contamination on ecosystems and human health at local and regional scale to prioritize and classify risks through deterministic and stochastic approaches.
Papers dedicated to the presentation of newly developed methods in analytical geochemistry to be applied in the field or in laboratory are also within the topics of interest for the journal.