Review of the present-day geodynamics of the Pannonian basin: progress and problems

Abstract

We present a comprehensive review on what we have learned during the last decade and what we need to know in the future about the present-day crustal deformation and geodynamics of the Pannonian basin and its surroundings. The recent tectonic activity of the region is controlled primarily by the counterclockwise rotation of the Adriatic microplate relative to Europe around a pole in the Western Alps. Due to the indentation of this crustal block against the Southern Alpine–Dinaric fold and thrust belt, intense shortening is effecting these orogens as evidenced by the general seismicity pattern and crustal deformation. The present-day kinematics of the Pannonian basin shows that the area is pushed from the south-southwest. As a result, strike-slip to compressive faulting is observed well inside the Pannonian basin and, furthermore, the nearly complete absence of normal faulting in the whole study area suggests that extension in the Pannonian basin has been finished and structural inversion is in progress. Due to an increase of intraplate compressional stress the Pannonian lithosphere exhibits large-scale bending manifested by the Quaternary subsidence and uplift history. The orientation of the modern tectonic stress field in and around the Pannonian basin shows a remarkable radial pattern of maximum horizontal stress around the Adriatic microplate. N–S directed compression observed at its northern tip in the Southern Alps gradually becomes NE–SW oriented along the Dinaric belt. This pattern is further traceable well inside the Pannonian basin, while in the Vrancea zone of the southeastern Carpathians E–W to ESE–WNW directed compression can be determined. Finite element stress modelling suggests that the stress regime in the Pannonian basin is governed by distinct tectonic factors in the overall convergent setting associated with the Africa–Europe collision. The most important stress source appears to be the active push of the Adriatic microplate. Additional boundary conditions, such as the deformation of crustal blocks with different geometry and rigidity at the margin of the Pannonian–Carpathian area and the effect of active compression in the Vrancea zone, significantly influence the stress regime and pattern. Finally, with a brief overview about the principal aims of the Central Europe Regional Geodynamic Project (CERGOP), we argue for the need of further investigations applying the latest techniques of space geodesy (GPS). This international cooperation can provide an excellent opportunity to further develop our understanding of the recent crustal deformation in Central Europe and to refine concepts and models about the tectonic inversion of sedimentary basins with back-arc origin.