From maps and cross-sections to kinematic models: the impact of metamorphic petrology

Michel Ballèvre (1), Paola Manzotti (2), Benjamin Le Bayon (3) & Christophe Real (4)
(1) Géosciences Rennes, Université de Rennes, 35042 Rennes Cedex - France. Corresponding email: michel.ballevre@univ-rennes1.fr (2) Institut des Sciences de la Terre, Géopolis, Quartier Mouline, 1015 Lausanne –Suisse. (3) BRGM, Direction des Géoressources, 3 avenue Claude Guillemin, 45100 Orléans –France. (4) Dipartimento di Scienze della Terra, Università di Torino, via Valperga Caluso 35, 10125 Torino – Italia.

In the Western Alps, more than a century of geological mapping has provided an unrivalled basis for geometrical and kinematical analysis of a collision belt. Metamorphic petrology has complemented geological mapping by providing key information on (i) the structure and history of the pre-Alpine crust, (ii) the amount of subduction recorded by mineral assemblages, and (iii) the relative timing and amount of exhumation of the different slices involved in the nappe stack. Integration of these data with isotopic ages allows a discussion of kinematic models, and some inferences on the dynamics of the mountain belt.

Western Alps, tectonic history, metamorphic processes.