Geometry and kinematics of early Alpine nappes in a Briançonnais basement (Ambin Massif, Western Alps)

Abstract

Abstract Petrological and structural observations from the Ambin pre-alpine basement dome and from its Brianconnais and Piedmont covers show an early D1 nappe-forming event overprinted by a major D2 (+ D3) ductile shearing deformation. The D1 event is characterised by garnet-blueschist facies metamorphic assemblages retrogressed to greenschist facies conditions during D2 then D3 stages near the top of the dome. North-verging D1 structures preserved in the core of the dome are consistent with alpine evolutionary models, in which exhumation of HP–LT metamorphic alpine rocks occurs initially in a north–south direction. To cite this article: J. Ganne et al., C. R. Geoscience 336 (2004).