New data for the kinematic interpretation of the Alps–Apennines junction (Northwestern Italy)

Alps and Apennines are juxtaposed within an approximately 100 km-wide area covered by the Upper Eocene to Miocene successions of the Tertiary Piedmont Basin. The Upper Eocene–Oligocene evolution of this area was characterized to the north and west by the propagation of the SE-verging Southalpine thrust-fold belt that can be traced from the Po Plain subsurface until the Torino Hill-Saluzzese area, and to the south by a high-angle, broadly E–W oriented megashear zone that led to the juxtaposition of different crustal levels and controlled the development of a mosaic of partly independent sub-basins. Since the latest Oligocene the N-verging Apenninic tectonics prevailed in the collisional system and the Tertiary Piedmont Basin evolved as a wide thrust-top basin, bounded to the north by the N-verging Monferrato arc and characterized by a tectono-sedimentary evolution recording changes of subsidence and shift of depocentres in relation to crustal structures.