Conclusion
In conclusion, two major tectonic stages characterize the evolution of Alpine Corsica (Figs. 3,4):
(1) the orogenic stage, related to the Late Cretaceous–Middle Eocene east-dipping subduction and progressive underthrusting of the Corsican continental crust. This event ended with the arrival at the trench of the thick Corsican crust, which blocked the subduction in the late Mid-Eocene;
(2) a post-orogenic stage, stretching from the early Oligocene–Miocene to the present day, related with the west-dipping Apenninic subduction. This geodynamic context is responsible for the reactivation of pre-existing thrusts in transpression/transtension during the Corsica-Sardinia block rotation, which ended with the development of Miocene basins and their subsequent deformation. The extensional tectonics described by Jolivet at al. (1990); Daniel et al. (1996); Jolivet et al. (1998); Guyedan et al (2003) and references therein took place during this post-orogenic stage. Deformation related to this stage generally results in low-displacement reactivation of previous subduction- and syn-contractional exhumation-related fabrics and structures (see details in the second day of Field trip 2).
Figure 3. Palaeotectonic sketch maps
Palaeotectonic sketch maps for the evolution of Corsica/Northern Apennine orogenic system from Late Cretaceous to Oligocene in oblique aerial view (mainly based on Dewey et al. 1989; Cello et al. 1996; Gueguen et al. 1997; Lagabrielle and Polino 1998; Stampfli et al. 1998; Séranne 1999; Neugebauer et al. 2001; Michard et al. 2002; Dèzes et al. 2004; Rosenbaum and Lister 2005; Schettino and Turco 2006; Molli 2008). Thin black bar indicates the location of cross-sections of Fig. 5. In 4e are represented the Campidano, Valencia and Rhone valley grabens. Thin black line in each sketch are present-day longitudes and latitudes. Different others paleotectonic interpretation can be found in the literature between others Handy et al. (2010); Vignaroli et al. (2009); Argnani (2009); Schettino and Turco 2006; Lacombe and Jolivet, 2005; Faccenna et al. (2004) and references therein.
Figure 4. Evolutionary model
Evolutionary model for the Corsica/Northern Apennine orogenic system based on the first-order tectonic constraints from the former opposite continental margins and tectono-sedimentary evolution of Alpine Corsica and Tuscan-derived continental units (after Molli and Malavieille, 2010).