Tectono-sedimentary architecture of Mura-Zala and Drava Basins (Neogene Pannonian Basin System, Croatia and Hungary)

Exploration in the Mura-Zala and Drava basins is increasingly limited by lithostratigraphic models that cannot resolve the complex, diachronous tectono-sedimentary evolution of the southwestern Pannonian Basin System. A new regional geology framework was constructed with seismo-geological interpretation using 45,500 km of 2D seismic, 7,300 km 2 of 3D seismic, and 300 wells across 20,000 km 2 in Croatia and Hungary. Gross depositional environment analysis, structural mapping, and clinothem-based stratigraphy were applied to identify major tectonic surfaces, megasequences, and sediment-routing systems. The results define three Neogene megasequences that capture the transition from syn-rift half-graben formation through early post-rift stable subsiding basins to post-rift thermal subsidence and the large-scale regression in Lake Pannon. The identification of 60 individual rift half-grabens provides a detailed structural template that explains the spatial variability of syn-rift/early post-rift accommodation and subsidence. Their distribution clarifies the segmentation of the extensional system, revealing discrete depocenters that governed sediment entry points, facies architecture, and early reservoir development. Fifteen post-rift clinothems were mapped, revealing systematic shifts in shelf-edge trajectories, sediment pathways, and depocenter migration. Basin wide structural surfaces including the rift onset unconformity, Middle Miocene inversion surface, and base Pannonian boundary were correlated consistently for the first time. The new tectono-sedimentological model will enhance prediction of reservoir, seal, and source-rock distribution and identifies remaining stratigraphic and subtle structural plays in a mature basin system.