Pre-collisional architecture of the European distal margin: Inferences from the high-pressure continental units of central Corsica (France)

The Lower Units of Alpine Corsica, France, are fragments of continental crust strongly deformed and metamorphosed under high-pressure metamorphic condi- tions. Three slices of Lower Units are well exposed in the area between the Asco and Tavignano valleys, Central Corsica. Despite their complex structural setting, they pro- vide the opportunity for a reconstruction of the pristine stratigraphic setting of the Lower Units. In our reconstruc- tion, these units consist of a Paleozoic basement topped by Triassic to Early Jurassic sedimentary rocks unconform- ably covered by Middle to Late Eocene foredeep deposits. However, the three units exposed in the study area dis- play strong differences mainly in the thickness of the Mesozoic sequence. These differences are here inter- preted as acquired during the first stage of the rifting process in a setting controlled by normal faults. During the collision-related tectonics and the accretion of the Lower Units to the Alpine orogenic wedge, these normal faults were probably reactivated with a reverse kine- matics. The stratigraphic logs of the Lower Units strictly resemble those of the Pre-Piedmont Units from Western Alps. This similarity indicates a common origin of the Lower Units and the Pre-Piedmont Units from the same domain (i.e., the European distal continental margin).