Present-day stress field in the Pannonian Basin and the surrounding Alpine-Car-pathian-Dinaric orogens

Abstract

In this paper a new compilation of contemporaneous stress data and their tectonic interpretation are
presented for the Pannonian Basin and its tectonic environment, the Alpine-Carpathian-Dinaric
orogens. Extensional formation of the basin system started in the Early Miocéné, whereas its structural
reactivation has been taking place since Late Miocéné to recent times. Basin inversion is related to the
change in the régiónál stress field from a state of tension to compression. Compression and associated
deformation are mainly governed by the convergence between Adria and its buffer, the Alpine beit of
orogens. In the Friuli zone of the Southern Alps, where thrust faulting prevails, compression is
orthogonal to the strike of the mountain beit. More to the south-east, intense contraction is combined
with active strike-slip faulting constituting the dextral Dinaric transpressional corridor. Stresses are
transferred far from Adria into the Pannonian domain. A well-defined spatial variation of the stress field
results in a complex pattern of ongoing tectonic activity. From the edges of Adria towards the interior of
the Pannonian Basin, the dominant style of deformation gradually changes from pure contraction
through transpression to strike-slip faulting and, locally, transtension. The importance of late-stage
inversion in the Pannonian Basin is interpreted in a more generál context of structural reactivation of
back-arc basins. Possible sources of compression driving basin inversion are alsó identified and
discussed. The state of recent stress and deformation in the Pannonian Basin, particularly in its western
and southern part, are governed by the complex interaction of plate boundary and intraplate forces.
Counterclockwise rotation and north-north-east directed indentation of the Adriatic microplate appear
to be of key importance as the dominant source of compression ("Adria-push"). Intraplate stress sources,
such as buoyancy forces associated with elevated topography, and crustal as well as lithospheric
inhomogeneities can alsó play essential, yet rather local role.