Multistage development of a hydrothermal W deposit during the Variscan late-orogenic evolution: the Puy-les-Vignes breccia pipe (Massif Central, France)
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 hydrother...
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| Format: | Article |
| Language: | English |
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EDP Sciences
2021-01-01
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| Series: | BSGF - Earth Sciences Bulletin |
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| Online Access: | https://www.bsgf.fr/articles/bsgf/full_html/2021/01/bsgf200018/bsgf200018.html |
| _version_ | 1818740871113211904 |
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| author | Harlaux Matthieu Marignac Christian Mercadier Julien Poujol Marc Boiron Marie-Christine Kouzmanov Kalin Camacho Alfredo Alikouss Saïda Roméo Benjamin Mouthier Bernard Cuney Michel |
| author_facet | Harlaux Matthieu Marignac Christian Mercadier Julien Poujol Marc Boiron Marie-Christine Kouzmanov Kalin Camacho Alfredo Alikouss Saïda Roméo Benjamin Mouthier Bernard Cuney Michel |
| author_sort | Harlaux Matthieu |
| collection | DOAJ |
| description | 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 (< 9 wt.% NaCl eq) and were trapped at high-temperatures (> 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. |
| first_indexed | 2024-12-18T01:47:36Z |
| format | Article |
| id | doaj.art-8837e9a3ca6e432aaaaec8363cee8836 |
| institution | Directory Open Access Journal |
| issn | 1777-5817 |
| language | English |
| last_indexed | 2024-12-18T01:47:36Z |
| publishDate | 2021-01-01 |
| publisher | EDP Sciences |
| record_format | Article |
| series | BSGF - Earth Sciences Bulletin |
| spelling | doaj.art-8837e9a3ca6e432aaaaec8363cee88362022-12-21T21:25:09ZengEDP SciencesBSGF - Earth Sciences Bulletin1777-58172021-01-011923310.1051/bsgf/2021023bsgf200018Multistage development of a hydrothermal W deposit during the Variscan late-orogenic evolution: the Puy-les-Vignes breccia pipe (Massif Central, France)Harlaux Matthieuhttps://orcid.org/0000-0001-6095-0591Marignac Christian0Mercadier Julien1Poujol Marc2https://orcid.org/0000-0001-8682-2926Boiron Marie-Christine3Kouzmanov Kalin4Camacho Alfredo5Alikouss Saïda6Roméo Benjamin7Mouthier BernardCuney Michel8Université de Lorraine, CNRS, GeoRessourcesUniversité de Lorraine, CNRS, GeoRessourcesUniv Rennes, CNRS, Géosciences Rennes – UMR 6118Université de Lorraine, CNRS, GeoRessourcesDepartment of Earth Sciences, University of GenevaDepartment of Geological Sciences, University of ManitobaDepartment of Geology, Hassan II University of Casablanca, Geodynamics of old Chains LaboratorySOQUEM INC.Université de Lorraine, CNRS, GeoRessourcesThe 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 (< 9 wt.% NaCl eq) and were trapped at high-temperatures (> 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.https://www.bsgf.fr/articles/bsgf/full_html/2021/01/bsgf200018/bsgf200018.htmlpuy-les-vignes depositbreccia pipewolframite mineralizationperaluminous granitefrench massif centralvariscan belt |
| spellingShingle | Harlaux Matthieu Marignac Christian Mercadier Julien Poujol Marc Boiron Marie-Christine Kouzmanov Kalin Camacho Alfredo Alikouss Saïda Roméo Benjamin Mouthier Bernard Cuney Michel Multistage development of a hydrothermal W deposit during the Variscan late-orogenic evolution: the Puy-les-Vignes breccia pipe (Massif Central, France) BSGF - Earth Sciences Bulletin puy-les-vignes deposit breccia pipe wolframite mineralization peraluminous granite french massif central variscan belt |
| title | Multistage development of a hydrothermal W deposit during the Variscan late-orogenic evolution: the Puy-les-Vignes breccia pipe (Massif Central, France) |
| title_full | Multistage development of a hydrothermal W deposit during the Variscan late-orogenic evolution: the Puy-les-Vignes breccia pipe (Massif Central, France) |
| title_fullStr | Multistage development of a hydrothermal W deposit during the Variscan late-orogenic evolution: the Puy-les-Vignes breccia pipe (Massif Central, France) |
| title_full_unstemmed | Multistage development of a hydrothermal W deposit during the Variscan late-orogenic evolution: the Puy-les-Vignes breccia pipe (Massif Central, France) |
| title_short | Multistage development of a hydrothermal W deposit during the Variscan late-orogenic evolution: the Puy-les-Vignes breccia pipe (Massif Central, France) |
| title_sort | multistage development of a hydrothermal w deposit during the variscan late orogenic evolution the puy les vignes breccia pipe massif central france |
| topic | puy-les-vignes deposit breccia pipe wolframite mineralization peraluminous granite french massif central variscan belt |
| url | https://www.bsgf.fr/articles/bsgf/full_html/2021/01/bsgf200018/bsgf200018.html |
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