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

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 re lated to the formation of the Pannonian Basin. Especially in the northernmo st Dinarides Neogene deformation played a very important role in the evolut ion 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 th e Tethys ophiolites were obducted onto the northeastern margins of the Apul ian microplate. The second phase is documented in the central part of the n orthernmost Dinarides. It is genetically related to an ancient volcanic are , as indicated by Late Cretaceous-Palaeogene trench sediments with blueschi st 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 ter minated 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. Penecontemporaneo us andesites which an found along the Drava and Sava depressions of the Sou th Pannonian Neogene Basin can be correlated with the easternmost Periadria tic tonalites. However, observations do not indicate strike-slip faulting a t 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 Pa nnonian alkali basalts, which are interlayered by coeval sedimentary rocks. Main evidence for the large-scale tectonic transport of large Dinaridic bl ocks into the Pannonian Basin area are the Periadriatic-Sava and Zagreb-Zem plen fault systems and subparallel faults. The late Sarmatian global sea-le vel drop which coincided with a compressional phase is regionally marked by an unconformity throughout the Pannonian Basin, as reported by Horvath (Ho rvath, F., 1995. Phases of compression during the evolution of the Pannonia n 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 Basi n. The Pliocene compression phase can be observed in the Transdanubian zone and also south of the Mura and Drava rivers by south- and southwest-dippin g reverse fault systems. (C) 1998 Elsevier Science B.V. All rights reserved .