Deformación de cizalla en el domo migmatítico de St. Malo (Macizo Armoricano, oeste de Francia)

Abstract

The Cadomian migmatite dome of St. Malo is affected by centimetric to metric shear bands. The shear bands bear a stretching lineation underlined by alignments of fibrous sillimanite crystals at Dinard and St. Briac outcrops. These shear bands were analysed by means of the Right Dihedra method. They indicate a NNE-SSW stretching direction and a subvertical shortening direction. They are consistent with foliation and stretching lineation orientations. This study suggests that the St. Malo migmatite dome was affected by a post-orogenic extensional tectonic regime