From the Eastern Paratethys to the Pontocaspian basins: late Miocene–Middle Pleistocene magneto-biostratigraphy, sedimentary architecture and faunal turnovers of the shrinking basins of West Eurasia.

Abstract

The Eastern Paratethys represents a large epicontinental sea that was spread on a vast territory of West Eurasia. In the late Miocene, intensification of regional orogenic processes and enhanced climatic oscillations isolated and segmented this sea into two small remnants – the Black and Caspian Seas, combined also known as Pontocaspian region. The transition from Paratethys to Pontocaspian system was accompanied by a complex history of interbasinal connections, basin-level drops and expansions, and biological turnovers that eventually shaped the modern endemic Pontocaspian ecosystems. Faunal migration paths, relations between taxa and drivers of ecosystem remain unclear, however, often due to the lack of robust age constraints and interdisciplinary studies. This thesis aims at dating and reconstructing the paleoenvironmental conditions responsible for the major biological turnovers in the region. It focuses on three key-intervals on a west-to-east transect: the late Miocene (~7.7 –6.0 Ma) of the Dacian Basin of Romania; the Miocene–Pliocene transition (~6.0–5.2 Ma) in the Denizli Basin of Turkey; the latest Pliocene–Middle Pleistocene (~2.7–0.5 Ma) in the Kura Basin of Azerbaijan. The new data especially shows that short episodes of re-established connection with intra-Paratethyan basins and with the global ocean triggered changes in the hydrological balance and water salinity, facilitating invasions of new faunal groups. This study thereby contributes to the refinement of the regional stratigraphic time scale that will serve as a backbone for further palaeoenvironmental studies.