The effect of inversion tectonics on the Late Miocene sedimentary system in the western Pannonian Basin, Hungary: A study based on seismic interpretation

Abstract

The Pannonian Basin of Central Europe, a Cenozoic back-arc basin enclosed between the Alps, Dinarides and Carpathians, underwent several stages of extension and inversion. The uplift of the surrounding mountains, at the earliest Late Miocene, led to the birth of Lake Pannon. Large rivers transported sediments into this isolated lake. Particularly, the paleo-Danube and paleo-Tisza progressively filled the lake dominantly from the northern margins. Previous studies have indicated that the timing of the shelf progradation ranged between ~10-4 Ma from NW to SE. However, the link between tectonic inversion and the sedimentary infill of the basin is much less understood. In this study I used a combination of seismic and well data interpretation and cross-section reconstruction coupled to a palaeobathymetric dataset. My reconstruction quantifies the considerable thickness differences in the palaeobathymetric evolution between the paleo-highs and deep depocentres. The effects of external and internal tectonic and sedimentary forcing factors on the height of the prograding shelf-margin slope have been compared and analyzed. The climatic control is believed to have minor impact on these variations; only lake level rise is observed of max ~100 m. No major drops in lake level have been observed, as any indications of incision or erosion of the shelf are absent. Other forcing factors as the existing paleo-relief, differential compaction and syn-sedimentary tectonics (subsidence and uplift) play a major role on the temporal and spatial variations of the palaeobathymetry. The late stage inversion had a major influence on the overall sedimentary transport system, as the uplift created barriers between confined basins, resulting in sediment ponding and subsequently sediment starvation behind these highs. The proposed tectonic and sedimentary evolutionary model based on seismic and well data interpretation of the Pannonian Basin can be applied in similar inverted extensional basins as well.