A different stratigraphic approach to reconstruct the Karpatian and Badenian seas in Central Europe

The Paratethys sea region in Central Europe experienced many paleogeographic changes during the Early-Middle Miocene. The interplay between tectonics, basin infill and eustatic sea level variations caused the existence of different marine transgressions. In many localities marine sediments of the Early Miocene ‘Karpatian’ stage are discordantly covered by marine deposits of the Middle Miocene ‘Badenian’ stage. Distinguishing and precise dating of the different marine deposits has always been a challenge. Two difficulties are the scarcity of reliable age constraints and the fact that the regional time scale is partly based on endemic fauna and regional sea level variations that cannot be compared directly to the global record. Therefore, foraminifers and nannoplankton species are being widely used for correlation to the global time scale (e.g. Hohenegger et al., 2009; Coric et al., 2009). Most Central Paratethys research is using the biostratigraphic scheme of the Atlantic Ocean to date the successions (e.g. NN-zones). The ages of these bio-events can differ over 0.5 Myrs from those in the recently revised Mediterranean biostratigraphic schemes (e.g. MNN-zones) by Iaccarino et al. (2011) and Di Stefano et al. (2011). Here, we use the Mediterranean schemes to re-date the classic Paratethys successions of the Central Paratethys basins. This alternative approach leads to the following reconstruction of the region. The Karpatian sea stretched from the North Alpine Foreland Basin (S. Germany and Switzerland) to the Styrian and Vienna basins and was most likely connected to the Mediterranean via the Rhone Valley (Berger et al., 2005). Around 16.2 Ma the sea retreated westward. During a period of ~ 1 Myr (16.2 to 15.2 Ma) almost no marine sediments are present in the Central Paratethys, which is related to a tectonic reconfiguration termed the ‘Styrian phase’. Subsequently the Badenian transgression occurred through a connection via the Transtethyan corridor in Slovenia and is related to extension in the Pannonian Basin. The sea covered Central Europe from the south (Croatian basins) to the north-west (Austrian Molasse and Vienna basins) and east (Transylvanian basin). Meanwhile, the Western Paratethys region remained continental (Figure 1). References Berger, J.-P., Reichenbacher, B., Becker, D., Grimm, M., Grimm, K., Picot, L. and Schaefer, A. (2005). Paleogeography of the Upper Rhine Graben (URG) and the Swiss Molasse Basin (SMB) from Eocene to Pliocene. International Journal of Earth Sciences, 94(4), 697–710. Ćorić, S., Pavelić, D., Rögl, F., Mandic, O., & Vrabac, S. (2009). Revised Middle Miocene datum for initial marine fl ooding of North Croatian Basins (Pannonian Basin System, Central Paratethys). Geologica Croatica, 62(1), 31–43. Di Stefano, A., Verducci, M., Cascella, A. and Iaccarino, S.M. (2011).Calcareous plankton events at the Early/Middle Miocene transition of DSDP Hole 608: comparison with Mediterranean successions for the definition of the Langhian GSSP. Stratigraphy 8: 145-161. Hohenegger J., Rögl F., Ćorić S., Pervesler P., Lirer F., Roetzel R., Scholger R. & Stingl K. 2009: The Styrian Basin: a key to the Middle Miocene (Badenian/Langhian) Central Paratethys transgressions. Austrian J. Earth Sci. 102, 102—132. Iaccarino, S. M., Stefano, A. Di, Foresi, L. M., Turco, E., Baldassini, N., Cascella, A. … (2011). High-resolution integrated stratigraphy of the upper Burdigalian-lower Langhian in the Mediterranean : the Langhian historical stratotype and new candidate sections for defining its GSSP. Stratigraphy, 8 (1960), 199–215..