The tectonic half-window of Cima Pedani (Alpine Corsica, France): an example of exhumed continental crust in collisional belt

The Cima Pedani half-window (Central Corsica, France) can be regarded as a key-area to reconstruct the tectonic history of the Alpine Corsica. In this area, not wider than 12 km2, the mutual relationships between the oceanic and continental units that characterize the tectonic setting of the Alpine Corsica are well preserved. These units are, from the bottom to the top, the Lower Units, the Schistes Lustrés Complex and the Upper Units. The Lower Units have a continental affinity and represent the portion of the European margin deformed and metamorphosed during the Alpine orogeny (Malasoma et al., 2006). Three units (Canavaggia, Pedani and Scoltola Units), similar in the lithostratigraphy and in the deformation history, have been distinguished on the base of the metamorphic conditions reached during their exhumation paths. The Schistes Lustrés Complex represents the stack of units of both continental and oceanic affinity that were subducted at the deepest levels during the closure of the Ligure-Piemontese basin. In the Cima Pedani area the Schistes Lustrés Complex is represented by the Lento Unit, a fragment of oceanic lithosphere deformed under blueschist facies metamoprhic conditions (Levi et al., 2007). The Upper Units consist of both continental and oceanic units, all characterized by a very weak deformation and metamoprhism. In the area two units of oceanic affinity crop out: the Serra- Debbione and the Pineto Units, both represented by an ophiolite sequence. The Serra- Debbione Unit is located to the north of the Cima Pedani half window and is separated the Lower Units by a normal fault. In turn, the Pineto Unit, located west of Cima Pedani half window, is separated from the Lower Units by the Central Corsica Shear Zone, a sinistral strike-slip fault active during the Late Eocene-Early Oligocene time span (Lacombe and Jolivet, 2005). The meso- and micro-structural analysis coupled with the reconstruction of the P-T-d paths of Canavaggia, Pedani and Scoltola Units allowed to reconstruct the tectono-metamorphic history of the Lower Units in the Late Eocene-Early Miocene, thus providing useful constraints for their coupling with the Schistes Lustrés and the Upper Units.