The Miocene palaeogeographic evolution of the Paratethys Sea is still poorly constrained. Here, we use modern Mediterranean biochronology to provide an up‐to‐date overview of changing seas in Central Europe. Instead of a Paratethys that waxed and waned with fluctuating global sea levels, we show that the development of different seas was mainly controlled by tectonic phases. The Early Miocene “Ottnangian Sea” (~18 Ma) was connected to the Mediterranean via the Rhône valley, while the “Karpatian Sea” (~16.5 Ma) was initiated by a tectonically induced marine transgression through the Trans‐Tethyan gateway. In most Central European basins, the establishment of the “Badenian Sea” (<15.2 Ma), triggered by subduction‐related processes in the Pannonian and Carpathian domain, is significantly younger (by ~1 Myr) than usually estimated. The updated palaeogeographic reconstructions provide a better understanding of the concepts of basin dynamics, land–sea distribution and palaeoenvironmental change in the Miocene of Central Europe.

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With 12 figures and 2 tables Abstract. During the Early to Middle Miocene, a complex interplay of climate variability, sea level change, and Alpine tectonics resulted in the development of a series of long-lived lakes in the Dinarides and Serbian regions. While recent dating studies improved understanding of the Dinaride Lake System (DLS) evolution, independent age constraints are still lacking for the Serbian Lake System (SLS). Here, we present the results of an integrated study combining biostratigraphy, magnetostratigraphy, and 40 Ar/ 39 Ar radioisotopic dating of the sedimentary succession of ancient Lake Popovac to improve the chronostratigraphic framework and paleoenvironmental understanding of the SLS. Our biostratigraphic analyses of the mollusks and ostracods show endemic marker taxa for the Middle Miocene bioprovince of the SLS, such as Prososthenia fuchsi PAVLOVIĆ, ?Mediocypris sp., and ?Dinarocythere sp. Magnetostratigraphy revealed only one normal polarity interval, with a single reversed sample on top and, combined with an 40 Ar/ 39 Ar weighted mean crystallization age of 14.40 Ȁ 0.01 Ma, we correlate the studied Lake Popovac succession to Chron C5ADn, with a maximum extent from 14.61-14.16 Ma. Cyclostratigraphic analysis based on magnetic susceptibility and natural gamma radiation field logs suggest insolation forcing of the succession with an upward decrease in sedimentation rate from 25 to 12 cm/kyr. While the majority of the DLS originated during the Miocene Climatic Optimum (MCO) at ~17 Ma and disappeared before ~15 Ma, the development of the SLS started around 14.5 Ma in the Langhian. Regionally overlying Serravallian marine sediments of the Central Paratethys imply that the Serbian Lake cycle must have ended before 13.8 Ma. Initiation of SLS deposition in the study area coincided with a peak of syn-rift extension in the Pannonian back-arc basin, which apparently also affected the Peri-Pannonian realm as far south as the study area in the Morava depression.

Dating of upper Miocene sediments of the Pannonian Basin (Hungary) has proven difficult due to the endemic nature of biota, scarcity of reliable radio isotopic data, and generally inconsistent magnetostratigraphic results. The natural remanent magnetization (NRM) is mostly residing in greigite (Fe3S4), which complicates NRM interpretation. We reinvestigate the viability of these sediments for magnetostratigraphy using samples from recently drilled well cores (PAET‐30 and PAET‐34) from the Paks region. Significant intervals of the cores contain composite NRM behavior. Thermal demagnetization results include multipolarity (M‐type) samples consisting of a low‐temperature (LT, above ~120 °C), a medium‐temperature (MT), and a high‐temperature (HT) component, within distinct temperature ranges and all exhibiting dual polarities. The LT and HT components have the same polarity and are antiparallel to the MT component. Rock magnetic and scanning electron microscopy results indicate that all magnetic components reside in authigenic greigite. The LT and HT components represent the characteristic remanent magnetization and are of early diagenetic origin. The MT component records a late diagenetic overprint. Alternating field demagnetization cannot resolve the individual components: it yields polarities corresponding to the dominant component resulting in erratic polarity patterns. Interpretation of LT and HT components allows a reasonably robust magnetostratigraphic correlation to the geomagnetic polarity time scale with the base of PAET‐30 at ~8.4 Ma and its top at ~6.8 Ma (average sedimentation rate of ~30 cm/kyr). The base of PAET‐34 is correlated to ~9 Ma and its top to ~6.8 Ma (average sedimentation rate of 27 cm/kyr).

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