Lithosphere model of the Pannonian-Adriatic overthrusting

- Gravity model was established at the contact of the Pannonian basin and Dinarides.
- A more reliable lithosphere model of the survey area was constructed.
- Push of the African plate and Pannonian asthenosphere upwelling have been considered.
- Crust thickening and sinking of the Adriatic mantle below the Dinarides were confirmed.
- The model shows the thrusting of the Adriatic microplate under the European plate.

A gravity model has been established at the contact of the southern part of the Pannonian basin and central Dinarides. Two-dimensional gravity modelling was carried out by means of the calibrated density set, defined at the Alp07 profile (Å umanovac, 2010), which significantly improved the resolution of the method. Gravity attraction caused by the structure in the upper mantle was analyzed in detail, which enabled construction of complete lithosphere model at the contact of the Dinarides, as a part of the Adriatic microplate, and the Pannonian basin as a segment of the Eurasian plate.Geophysical models demonstrate that overthrusting structures need to be considered in the present geological model; notably, the thrusting of the Adriatic microplate under the European plate. However, overthrusting processes cannot provide a complete explanation of the processes in the Pannonian basin. Considering that the Pannonian basin area is in fact a large geothermal anomaly, it is necessary to introduce the asthenosphere upwelling into the model. The presence of this structure is confirmed by a change in densities and seismic velocities in the uppermost mantle. This process has led to a significant thinning of the crust in the Tisia block and to the homogenization of properties as a result of the rising of the asthenosphere, and the crust can therefore be considered as a single layer. The combined effect of the push exerted by the African plate, and the rising of the asthenosphere and the thinning of the crust in the Pannonian basin caused the underthrusting of the Adriatic microplate below the Pannonian segment, thickening of the crust and steeply sinking of the Adriatic upper mantle below the Dinarides. Seismicity of the area and earthquake hypocenters enable the construction of active faults, which correlate well with the main faults at the surface and boundaries of density blocks in the crust.