Relationships between granitoids and mineral deposits: three-dimensional modelling of the Variscan Limousin Province (NW French Massif Central)

Christian Le Carlier de Veslud and Michel Cuney and Jean-Jacques Royer and J. P. Floc and L. Améglio and P. Alexandrov and J. L. Vigneresse and P. Chevremont and Y. Itard. ( 2001 )
in: Geol. Soc. Am. Bull., 350 (283--301)

Abstract

Multidisciplinar three-dimensional modelling, involving geophysical, structural and geochemical data, has been used to stud the relationships between magmatism, tectonics, fluid circulation and mineralisation in the northern Limousin, and to provide P-T-Z-t paths constrained by the available dating. The ore deposit occurence displays little spatial relationship with granites emplaced in the 36-32 Ma period, probably because the low glabol permeability and tectonic regime did not allowed vertical fluid exchanges to be established. In contrast, the change in the tectonic regime induced by the delamination of the lower lithospere (320-300Ma), and characterised by the passage to general extension, has played a major metallogenic role. However, the ore deposit processes appear to be specific to each metal. Most of the W-Sn deposits appear to be synchronous with rare metal granites emplacement, at c. 310 Ma, that allowed the focus of fluids of differnte origins towards the apex of plutons. In contrast, for Au and U, the wholde mineralisation process covers several tens of millions of years. It is controlled by the regional tectonic evolution of the Limousin area during the same period, and especiall by a rapid exhumation of the ductile crust which occured in the 310-300 Ma period.

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    BibTeX Reference

    @ARTICLE{LeCarlier01,
        author = { Le Carlier de Veslud, Christian and Cuney, Michel and Royer, Jean-Jacques and Floc, J. P. and Améglio, L. and Alexandrov, P. and Vigneresse, J. L. and Chevremont, P. and Itard, Y. },
         title = { Relationships between granitoids and mineral deposits: three-dimensional modelling of the Variscan Limousin Province (NW French Massif Central) },
       journal = { Geol. Soc. Am. Bull. },
        volume = { 350 },
       chapter = { 0 },
          year = { 2001 },
         pages = { 283--301 },
      abstract = { Multidisciplinar three-dimensional modelling, involving geophysical, structural and geochemical data, has been used to stud the relationships between magmatism, tectonics, fluid circulation and mineralisation in the northern Limousin, and to provide P-T-Z-t paths constrained by the available dating. The ore deposit occurence displays little spatial relationship with granites emplaced in the 36-32 Ma period, probably because the low glabol permeability and tectonic regime did not allowed vertical fluid exchanges to be established. In contrast, the change in the tectonic regime induced by the delamination of the lower lithospere (320-300Ma), and characterised by the passage to general extension, has played a major metallogenic role. However, the ore deposit processes appear to be specific to each metal. Most of the W-Sn deposits appear to be synchronous with rare metal granites emplacement, at c. 310 Ma, that allowed the focus of fluids of differnte origins towards the apex of plutons. In contrast, for Au and U, the wholde mineralisation process covers several tens of millions of years. It is controlled by the regional tectonic evolution of the Limousin area during the same period, and especiall by a rapid exhumation of the ductile crust which occured in the 310-300 Ma period. }
    }