ABSTRACT: Since the conception of the Mediterranean Messinian Salinity Crisis model in the 1970s, regional unconformities as candidates for indicators of a correlative base level drop have been sought in the neighbouring Paratethyan basins. Some authors have suggested that seismic sections and borehole profiles from the Late Miocene to Pliocene lacustrine to fluvial succession of the Central Paratethyan Pannonian Basin include such unconformities. We argue that none of these unconformities evidence a significant drop in water-levels. One type of such unconformities is marked by the onlap of seismic reflections onto the lower portion of the shelf-edge clinoforms, a feature repeatedly observed in the eastern Hungarian part of the basin. This geometry, however, resulted from strike variability of the sediment feeder system, thus it is a local phenomenon which does not necessarily justify general base level drops. The only regional unconformity was observed on the shelf, not on the slope. It separates originally flat-lying Messinian deltaic-fluvial deposits from the overlying Pliocene fluvial-terrestrial sediments. This surface can be traced along the entire length of the northern basin margin both in seismic and borehole data. The unconformity is angular and thus has a tectonic origin. It is tilted together with the underlying sediments toward the basin proper, indicating the onset of basin inversion in the latest Miocene or earliest Pliocene. Thus, the seismic and borehole data published so far from the Pannonian Basin do not evidence that thewater level of the Central Paratethys was directly influenced by the drawdown of the Mediterranean or the Eastern Paratethys.
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