Late Cretaceous and Cenozoic intra-plate compressional deformations in the Alpine foreland—a geodynamic model

Abstract

The Mesozoic grabens and wrench induced troughs of Western and Central Europe developed in response to Triassic-Early Cretaceous intra-plate tensional stresses which affected the Arctic-North Atlantic and the Tethys borderlands during the rifting phase preceding the opening of the respective oceans. This resulted in the fragmentation of the continental crust of the Alpine foreland. During the Late Cretaceous and Tertiary Alpine orogeny, collision related compressive stresses exerted on the foreland induced the reactivation of these fracture systems, causing the inversion of Mesozoic grabens and the uplifting of major basement blocks at distances up to 1300 km to the north of the present Alpine deformation front.

The structural style of these inverted basins and basement uplifts is indicative of compressional and transpressional deformations. The total amount of crustal shortening associated with these deformations is unlikely to exceed a few tens of kilometres. These displacements require a coupling between the foreland and the orogen at the Alpine A-subduction zones and, within the foreland, a decoupling at intra-crustal levels, between the crust and mantle and/or at deeper lithospheric levels.

The example of the Alpine foreland indicates that compressive stresses, inducing major deformations, can be transmitted from a collisional plate boundary through continental lithosphere over distances of up to 1300 km. Circumstantial evidence suggests that collision related compressive stresses not large enough to give rise to significant deformations can be transmitted through continental lithosphere over even greater distances.