Geodynamic evolution of the northern Dinarides and the southern part of the Pannonian Basin

Abstract

Most of the recent geodynamic interpretations of the Pannonian Basin focus on its relation to the formation of the Carpathians and the Alpine orogeny. However, also the Dinarides were severely affected by Neogene tectonics related to the formation of the Pannonian Basin. Especially in the northernmost Dinarides Neogene deformation played a very important role in the evolution of this mountain chain. Geological records clearly show evidence of two phases of plate convergence along the northern and eastern margins of the present-day Dinarides. At the end of the Jurassic the Dinaridic parts of the Tethys ophiolites were obducted onto the northeastern margins of the Apulian microplate. The second phase is documented in the central part of the northernmost Dinarides. It is genetically related to an ancient volcanic arc, as indicated by Late Cretaceous–Palaeogene trench sediments with blueschist olistolithes which are interlayered by basalt, rhyolites, pyroclastics, medium-pressure metamorphosed trench sediments, and associated synkinematic granitoids. In the northern part of the Dinarides subduction processes terminated with the Eocene compressional event which caused the uplift of the Dinarides. Numerous intramontane basins with shallow-marine, fluviatile and lacustrine deposits were generated during the Oligocene. Penecontemporaneous andesites which are found along the Drava and Sava depressions of the South Pannonian Neogene Basin can be correlated with the easternmost Periadriatic tonalites. However, observations do not indicate strike-slip faulting at that time in this area. The Neogene rift stage initiated the evolution of the Pannonian Basin. It is marked by extruded submarine trachyandesites of Karpathian age, Badenian basalts, andesites, dacites and rhyolites, and Pannonian alkali basalts, which are interlayered by coeval sedimentary rocks. Main evidence for the large-scale tectonic transport of large Dinaridic blocks into the Pannonian Basin area are the Periadriatic–Sava and Zagreb–Zemplen fault systems and subparallel faults. The late Sarmatian global sea-level drop which coincided with a compressional phase is regionally marked by an unconformity throughout the Pannonian Basin, as reported by Horváth (Horváth, F., 1995. Phases of compression during the evolution of the Pannonian Basin and its bearing on hydrocarbon exploration. Mar. Pet. Geol. 12 (8), 837-844). Due to thermal subsidence during the Pliocene more than 2000 m of lacustrine freshwater sediments were deposited in the South Pannonian Basin. The Pliocene compression phase can be observed in the Transdanubian zone and also south of the Mura and Drava rivers by south- and southwest-dipping reverse fault systems.