000120108 001__ 120108 000120108 005__ 20240319081022.0 000120108 0247_ $$2doi$$a10.1016/j.geothermics.2022.102573 000120108 0248_ $$2sideral$$a130890 000120108 037__ $$aART-2022-130890 000120108 041__ $$aeng 000120108 100__ $$0(orcid)0000-0002-2698-789X$$aJiménez, J.$$uUniversidad de Zaragoza 000120108 245__ $$aGeochemical characterisation and modelling of the Luchon hydrothermal system (Central Pyrenees, France) and lessons learnt for the use of geochemical modelling techniques in granite-hosted alkaline thermal waters 000120108 260__ $$c2022 000120108 5060_ $$aAccess copy available to the general public$$fUnrestricted 000120108 5203_ $$aAlkaline hydrothermal systems hosted in granitic rocks have been extensively investigated as natural analogues for radioactive waste disposal and for the geological storage of CO2. Thereby, their geochemical characterisation provides useful information for the long-term performance assessment predictions. The geochemical modelling of one of these alkaline hydrothermal systems has been performed in Luchon (France), together with the application of different geothermometrical techniques to determine the temperature, pH and mineral equilibrium conditions at depth. The modelling results show that the main processes controlling the hydrogeochemical evolution of this system are: (1) the mixing between deep thermal and cold surface waters, (2) the conductive cooling and (3) the external input of CO2. Other important results are that the most alkaline thermal waters are characterised by a high pH-buffering capacity during the mixing processes, and that the high pH values that characterise these thermal waters are not only inherited from the deep reservoir but strongly enhanced by conductive cooling. The reservoir temperature predicted by the geothermometrical modelling is in the range of 117 ± 8 °C, in good agreement with the temperatures ranging from 108 to 133 °C predicted by the classical geothermometers. The results of these calculations indicate as well that the thermal solutions have reached equilibrium with quartz, albite, potassium feldspar, zoisite and prehnite, and that a re-equilibirum with kaolinite and calcite is reached during their ascent to the surface. Another important outcome is that the precipitation of calcite in the deep reservoir could take place as a CO2 mineral trapping mechanism in similar systems. Further, the sharp influence of the surface waters on the deep thermal waters reveals a high susceptibility of the system to potential contamination processes. 000120108 540__ $$9info:eu-repo/semantics/openAccess$$aby-nc-nd$$uhttp://creativecommons.org/licenses/by-nc-nd/3.0/es/ 000120108 590__ $$a3.9$$b2022 000120108 592__ $$a0.912$$b2022 000120108 591__ $$aGEOSCIENCES, MULTIDISCIPLINARY$$b53 / 202 = 0.262$$c2022$$dQ2$$eT1 000120108 593__ $$aGeology$$c2022$$dQ1 000120108 591__ $$aENERGY & FUELS$$b70 / 119 = 0.588$$c2022$$dQ3$$eT2 000120108 593__ $$aGeotechnical Engineering and Engineering Geology$$c2022$$dQ1 000120108 593__ $$aRenewable Energy, Sustainability and the Environment$$c2022$$dQ2 000120108 594__ $$a6.8$$b2022 000120108 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000120108 700__ $$0(orcid)0000-0001-5645-9150$$aGimeno, M. J.$$uUniversidad de Zaragoza 000120108 700__ $$0(orcid)0000-0003-1463-1682$$aAuqué, L. F.$$uUniversidad de Zaragoza 000120108 7102_ $$12000$$2685$$aUniversidad de Zaragoza$$bDpto. Ciencias de la Tierra$$cÁrea Petrología y Geoquímica 000120108 773__ $$g106 (2022), 102573[14 pp.]$$pGeothermics$$tGEOTHERMICS$$x0375-6505 000120108 8564_ $$s10333592$$uhttps://zaguan.unizar.es/record/120108/files/texto_completo.pdf$$yVersión publicada 000120108 8564_ $$s2413439$$uhttps://zaguan.unizar.es/record/120108/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada 000120108 909CO $$ooai:zaguan.unizar.es:120108$$particulos$$pdriver 000120108 951__ $$a2024-03-18-16:18:05 000120108 980__ $$aARTICLE