{"title":"Fluid-rock reaction path modeling of uranium mobility in granite-related mineralization: A case study from the Variscan South Armorican Domain","authors":"Khaled Bock , Yannick Branquet , Olivier Pourret , Philippe Boulvais","doi":"10.1016/j.apgeochem.2024.106241","DOIUrl":null,"url":null,"abstract":"<div><div>The mobilization of uranium in granite-related systems presents a complex interplay of chemical and hydrodynamic factors. This is particularly obvious within syn-orogenic detachment zones where <em>per descensum</em> surface-derived fluids interact with <em>per ascensum</em> deeply sourced hydrothermal fluids. In this study, we employ a thermo-hydro-chemical (TH-C) modeling approach to explore the multifaceted processes that govern uranium transport and deposition in such environments. Our findings indicate that uranium mobility is not solely determined by the oxidizing nature of the percolating surface-derived fluids. Actually, the oxidation-reduction potential of these fluids varies as they flow in the crust, ultimately adjusting towards more neutral or mildly reducing conditions conducive to uranium dissolution and precipitation. Even in the presence of magnetite, which enhances the reductive potential of the fluids, uranium continues to dissolve, albeit in much smaller quantities, with U(IV) being the predominant species in the aqueous phase. The study highlights the crucial roles of temperature, pH, and fluid/rock interaction ratios in influencing uranium leaching efficacy. High fluid/rock ratios enhance uranium extraction from source rocks. A fluid/rock ratio around 1 is optimal, maximizing the dissolution of uranium-bearing minerals in the source rock and promoting the precipitation of uranium minerals in different locations along the fluid pathway due to changes in fluid chemistry. The TH-C modeling has the potential to be applied to a variety of other uranium deposits, developed below 300 °C.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"178 ","pages":"Article 106241"},"PeriodicalIF":3.1000,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Geochemistry","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0883292724003469","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
The mobilization of uranium in granite-related systems presents a complex interplay of chemical and hydrodynamic factors. This is particularly obvious within syn-orogenic detachment zones where per descensum surface-derived fluids interact with per ascensum deeply sourced hydrothermal fluids. In this study, we employ a thermo-hydro-chemical (TH-C) modeling approach to explore the multifaceted processes that govern uranium transport and deposition in such environments. Our findings indicate that uranium mobility is not solely determined by the oxidizing nature of the percolating surface-derived fluids. Actually, the oxidation-reduction potential of these fluids varies as they flow in the crust, ultimately adjusting towards more neutral or mildly reducing conditions conducive to uranium dissolution and precipitation. Even in the presence of magnetite, which enhances the reductive potential of the fluids, uranium continues to dissolve, albeit in much smaller quantities, with U(IV) being the predominant species in the aqueous phase. The study highlights the crucial roles of temperature, pH, and fluid/rock interaction ratios in influencing uranium leaching efficacy. High fluid/rock ratios enhance uranium extraction from source rocks. A fluid/rock ratio around 1 is optimal, maximizing the dissolution of uranium-bearing minerals in the source rock and promoting the precipitation of uranium minerals in different locations along the fluid pathway due to changes in fluid chemistry. The TH-C modeling has the potential to be applied to a variety of other uranium deposits, developed below 300 °C.
期刊介绍:
Applied Geochemistry is an international journal devoted to publication of original research papers, rapid research communications and selected review papers in geochemistry and urban geochemistry which have some practical application to an aspect of human endeavour, such as the preservation of the environment, health, waste disposal and the search for resources. Papers on applications of inorganic, organic and isotope geochemistry and geochemical processes are therefore welcome provided they meet the main criterion. Spatial and temporal monitoring case studies are only of interest to our international readership if they present new ideas of broad application.
Topics covered include: (1) Environmental geochemistry (including natural and anthropogenic aspects, and protection and remediation strategies); (2) Hydrogeochemistry (surface and groundwater); (3) Medical (urban) geochemistry; (4) The search for energy resources (in particular unconventional oil and gas or emerging metal resources); (5) Energy exploitation (in particular geothermal energy and CCS); (6) Upgrading of energy and mineral resources where there is a direct geochemical application; and (7) Waste disposal, including nuclear waste disposal.