Développement multiphasé d'un gîte hydrothermal à tungstène au cours de l'évolution tardi-orogénique varisque : le conduit bréchique à W de Puy-les-Vignes (Massif central, France)
| Autor: | Michel Cuney, Kalin Kouzmanov, Marc Poujol, Christian Marignac, Julien Mercadier, Benjamin Roméo, Alfredo Camacho, Bernard Mouthier, Marie-Christine Boiron, Saida Alikouss, Matthieu Harlaux |
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| Přispěvatelé: | GeoRessources, Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Institut national des sciences de l'Univers (INSU - CNRS), Géosciences Rennes (GR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), University of Geneva [Switzerland], University of Manitoba [Winnipeg], University Hassan II [Casablanca], ANR-10-LABX-0021,RESSOURCES21,Strategic metal resources of the 21st century(2010), ANR-14-EMIN-0001,NewOreS,Development of New models for the genesis of Rare Metal (W, Nb, Ta, Li) Ore deposits from the European Variscan Belt and valorization of low grade and fine grained ore and mine tailings(2014), Nevada Bureau of Mines & Geology, University of Nevada [Reno], SOQUEM, Department of Earth Sciences [Geneva], Institut national des sciences de l'Univers (INSU - CNRS)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Université de Genève = University of Geneva (UNIGE), ANR-10-LABX-21-RESSOURCES21, LABEX RESSOURCES 21, ANR-14-EMIN-0001, ERAMIN |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
wolframite mineralization
010504 meteorology & atmospheric sciences Metamorphic rock Hydrostatic pressure Geochemistry Metamorphism peraluminous granite 010502 geochemistry & geophysics 01 natural sciences granite peralumineux Breccia pipe [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry chaîne Varisque 10. No inequality variscan belt conduit bréchique 0105 earth and related environmental sciences Puy-les-Vignes deposit Massif Central Français First episode geography QE1-996.5 geography.geographical_feature_category Geology Massif minéralisation à wolframite Leucogranite [SDU]Sciences of the Universe [physics] Variscan belt gîte de Puy-les-Vignes Geochronology breccia pipe French Massif Central [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy |
| Zdroj: | Bulletin de la Société Géologique de France Bulletin de la Société Géologique de France, Société géologique de France, In press, ⟨10.1051/bsgf/2021023⟩ Bulletin de la Société Géologique de France, Société géologique de France, 2021, 192, pp.33. ⟨10.1051/bsgf/2021023⟩ BSGF-Earth Sciences Bulletin, Vol 192, p 33 (2021) Bulletin de la Société Géologique de France, Société géologique de France, 2021, 192, ⟨10.1051/bsgf/2021023⟩ Bulletin de la Société Géologique de France, 2021, 192, pp.33. ⟨10.1051/bsgf/2021023⟩ |
| ISSN: | 0037-9409 1777-5817 |
| Popis: | The Puy-les-Vignes W deposit, located in the northwestern French Massif Central (FMC), is a rare occurrence of a wolframite-mineralized hydrothermal breccia pipe hosted in high-grade metamorphic gneisses. We present an integrated study of this deposit aiming to characterize the ore-forming hydrothermal system in link with the Variscan late-orogenic evolution of the FMC. Based on a set of representative samples from the host rocks and mineralization, we describe a detailed paragenetic sequence and we provide the major and trace element geochemistry of the granitic rocks and W–Nb–Ta–Sn–Ti oxide minerals, in situ U/Pb and 40Ar/39Ar geochronology, and a fluid inclusion study of quartz and wolframite. We demonstrate that the formation of this W-mineralized breccia pipe results from a multistage development related to four major episodes during the late Carboniferous. The first episode corresponds to the emplacement of an unexposed peraluminous granite at ca. 324 Ma, which generated microgranite dykes exposed at the present-day surface. The second episode is the formation of the quartz-supported breccia pipe and wolframite mineralization at ca. 318 Ma at a paleodepth of 7 km. The mineralizing fluids have a H2O–NaCl–CO2–CH4–N2 composition, a moderate-salinity ( 400 °C) during lithostatic to hydrostatic pressure variations caused by hydrofracturing of the host rocks. Wolframite deposition is interpreted to result from a W-rich intermediate-density magmatic fluid that exsolved from an evolved leucogranite and interacted with volatile-rich metasedimentary country rocks and/or possibly mixed with low-salinity metamorphic fluids of deep origin. The third episode corresponds to magmatic-hydrothermal Nb–Ta mineralization overprinting the W-mineralized system interpreted to be related to the intrusion at ca. 311 Ma of a rare-metal granite, which is part of a regional peraluminous rare-metal magmatism during the 315–310 Ma period. Finally, the last episode corresponds to disseminated Bi ± Au–Ag mineralization emplaced at ca. 300 Ma, which shares similar mineralogical features with late Carboniferous orogenic gold deposits in the FMC. The Puy-les-Vignes W deposit records, therefore, a multistage and long-lived development that extends over a timespan of 25 million years in a regional setting dominated by protracted peraluminous magmatism and high-temperature and low-pressure metamorphism. Although the local environment of ore deposition is atypical, our results show that the mineral assemblages, alteration styles, and fluid characteristics of the Puy-les-Vignes breccia pipe are similar to those of other peri-granitic W deposits in the FMC. |
| Databáze: | OpenAIRE |
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