The formation and deformation of the Neogene Pannonian Basin: a structural overview

Abstract

The Pannonian Basin is a continental back-arc basin. Palaeomagnetics defined three terranes: Alcapa (Alps–Carapathians–Pannonian), Tisza–Dacia and Dinarides, rotated counterclockwise, clockwise and counterclockwise, respectively, in the Early and Middle Miocene. The timings and the extent of rotations suggest the terranes experienced differential internal rotations. Metamorphic core complexes occur along the margins and an internal part of the Pannonian Basin. Metamorphic core complexes display extension parallel then perpendicular to the margins. Low-temperature thermochronology defined that synrift exhumation occurred c. 18–16 Ma, coeval with map-view rotations. Microtectonic measurements evidenced superimposed fault patterns. When combined with palaeomagnetics, these patterns simplify to north–south compression throughout Late Paleogene–Middle Miocene. Complications result from rotating blocks deforming under this external stress field. Interpretation of seismic reflection data suggest that synrift phase was characterized by two perpendicular extensions. When rotations are considered, these resolve in east–west stretching. Strike-slip faulting during the Late Miocene accommodated differential movement of terranes pulled eastwards by slab roll-back along the Carpathians. Several inversions affect Late Miocene–Recent sediments. These are most intense and earliest in the SW Pannonian Basin, but also propagate into the internal parts. Rotational indentation of Adria into the Southern Alps–Western Dinarides is the main cause for inversion. Neotectonics reflect this inversion, that is enhanced by eastwards escaping Eastern Alps.