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International Journal of Earth Sciences

, Volume 101, Issue 1, pp 69–86 | Cite as

Geochronological and geochemical characterization of magmatic-hydrothermal events within the Southern Variscan external domain (Cévennes area, France)

  • A. ChauvetEmail author
  • N. Volland-Tuduri
  • C. Lerouge
  • V. Bouchot
  • P. Monié
  • X. Charonnat
  • M. Faure
Original Paper

Abstract

Geochronological, mineralogical, and geochemical analyses have been focussed on the Mont-Lozère-Borne plutonic complex and surrounding rocks (Cévennes, French Massif Central) in which B–W-Sn and As-Au-Sb mineralization is encountered. Two main results are highlighted: (1) the existence of a 301–306 Ma magmato-hydrothermal event unrelated to the emplacement of the Pont-de-Montvert-Borne plutonic body at 316 Ma; (2) the magmatic and hydrothermal features are strongly associated, both in time and in space, thus demonstrating an intimate connection between mineralizing processes and magmatism in this part of the French Massif Central. We also show that mineralization and associated hydrothermal occurrences do not correspond to a simple and single geochemical signature and that a contamination model must be invoked in order to account for the complexity of isotopic results. This study demonstrates that the application of the O and H isotopic signatures as tracers of the source and nature of fluids in an orogenic context requires some specific care. Finally, a model of the tectonic-magmatic-hydrothermal evolution of the study area is suggested in which we discuss two alternative scenarios. The first one implies the existence of two different hydrothermal/mineralizing events (Bo-W-Sn and As-Au-Sb ones). The second one suggests the same source for all hydrothermal and mineralized structures.

Keywords

40Ar/39Ar dating (H,O) isotope geochemistry Granite Hydrothermalism Aplite and pegmatite dykes Cévennes Variscan French Massif central 

Notes

Acknowledgments

The GéoFrance 3D program through BRGM, Ministry of Education and CNRS-INSU funds supported this study. Additional financial support from the CNRS-GDR TRANSMET was provided in order to achieve this study. J.P. Milesi is strongly acknowledged for his constant support and fruitful discussions.

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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • A. Chauvet
    • 1
    Email author
  • N. Volland-Tuduri
    • 2
  • C. Lerouge
    • 3
  • V. Bouchot
    • 3
  • P. Monié
    • 1
  • X. Charonnat
    • 2
  • M. Faure
    • 2
  1. 1.Géosciences MontpellierMontpellier Cedex 05France
  2. 2.Université d’OrléansOrléans Cedex 2France
  3. 3.BRGM, 3 avenue Claude GuilleminOrléans Cedex 2France

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