Transpressional tectonics and Carboniferous magmatism in the Limousin, Massif Central, France:structural and 40Ar/39Ar investigations.

Aude Gébelin (1) , Maurice Brunel (1) , Patrick Monié (1) , Michel Faure (2) , Nicolas Arnaud (1)

1 Géosciences Montpellier
2 ISTO - Institut des Sciences de la Terre d'Orléans

New structural, microstructural, and 40Ar/39Ar data from the NW Massif Central (France) provide additional constraints on the timing and tectonic setting of late Variscan granite magmatism. Previous studies had emphasized the role of late orogenic extension in the emplacement of granite plutons in the Limousin region. In contrast, the new data set is consistent with syntectonic emplacement of magma in a dextral simple shear active from 350 to 300 Ma in a transpressional regime. As an alternative hypothesis to late orogenic extension, we propose that magmas migrated into tensional bridges between active P shears associated with a lithospheric shear zone comparable to a pop-up structure. The Galician region, in the western end of the Ibero-Armorican tectonic arc, exhibits major left-lateral ductile shear zones which can be interpreted as conjugate structures to the Limousin and Armorican shear zones. Citation: Ge´belin, A., M. Brunel, P. Monie´, M. Faure, and N. Arnaud (2007), Transpressional tectonics and Carboniferous magmatism in the Limousin, Massif Central, France: Structural and 40Ar/39Ar investigations

Mots clés: French Massif Central.; 40Ar/39Ar dating; microtectonics; mylonite; granite; Variscan orogeny; French Massif Central

Domaines: Tectonique; Milieux et Changements globaux

Aude Gébelin, Maurice Brunel, Patrick Monié, Michel Faure, Nicolas Arnaud. Transpressional tectonics and Carboniferous magmatism in the Limousin, Massif Central, France:structural and 40Ar/39Ar investigations.. Tectonics, 2007, 26 (2), pp.TC2008. ⟨10.1029/2005TC001822⟩. ⟨hal-00104212⟩