Fig. 4

Geological cross-sections of the western Nice Arc between Aspremont and St Blaise (location on Fig. 2b). a Northern section: La Loubière-Mt Cima-Plan d’Arriou. b Southern section Aspermont-Les Salettes. Fold and fault geometries agree with a positive flower-type structure especially in the southern section below ‘Les Salettes’ (b). In both sections, close to ‘La Loubière’ (section a), and east of ‘Les Salettes (b), verticalization of the Pliocene emphasizes the Plio-Quaternary activity of the fault system. In addition, note the migration of basin depocenters from the Pliocene to the Quaternary times. Most deformation was acquired before the deposition of Pliocene, as shown by unconformity relationship of the Pliocene basin on the main folded and faulted Mesozoic structure. Cross-cutting of crystalline basement by the strike-slip faults in a ‘thick-skinned’ tectonic style is mainly suggested by the depth of regional focal mechanisms (c. 5 km) and absence of any significant cover-basement offset since 8 Ma by thermochronology in Sanchez et al. (2011a)