The role of the Periadriatic Line in the tectonic evolution of the Alps

Abstract
Summary: The Periadriatic Line and related lineaments formed as a result of post-collisional deformations which severely modified the Alpine chain. This post-late Oligocene deformation is the result of dextral transpression between the Adriatic sub-plate and the European foreland. Indentation of the western edge of the southern Alps caused uplift, related to backthrusting and associated deformations of the Lepontine region combined with E-directed escape of the central Alps. In the eastern Alps the response to dextral transpression is mainly by lateral escape along conjugate strike slip zones with minor or no vertical movements. Older deformations along this essentially late Alpine lineament can still be inferred locally and include: extension and transfer faulting in the late Palaeozoic to early Mesozoic, Cretaceous deformations, and Tertiary phases of compression (Eocene) and possibly extension (Oligocene). The geometry of crustal thinning associated with the formation of the passive continental margin of the southern Alps (associated with initial uplift of the Ivrea zone) has a profound influence on strain localization and the kinematics of movements along and north of the present day Periadriatic Line.