Mollusc assemblages of the Pontian and Dacian deposits from the Topolog-Argeş area (southern Carpathian foredeep – Romania)

Abstract

A better understanding of Mediterranean–Paratethys water-exchange during the Messinian Salinity Crisis has since long been hampered by the absence of a reliable time frame for the Paratethys. High-resolution magnetostratigraphic studies on the sedimentary sequences of the eastern and southern Carpathian foredeep recently resulted in an accurate chronology for the Mio-Pliocene deposits of the Dacic Basin of Romania. This allowed a straightforward correlation of the Pontian and Dacian stages to the geological time scale, which revived earlier discussions on Mediterranean–Paratethys connectivity. Here, we present Pontian and Dacian mollusc assemblages of the Getic Depression (Topolog-Argeş area, southern Carpathians) of Romania, which are incorporated in a magnetostratigraphic time frame. They indicate that a hiatus – comprising the Early Pontian – is present in the stratigraphic successions, which could be related to a base level drop of the Paratethys water column or to more local tectonic processes. The mollusc assemblages furthermore show a gradual transition at the Pontian/Dacian boundary, which is magnetostratigraphically dated at ∼4.9 Ma. This is significantly later (by more than 400 kyrs) than the Mio-Pliocene boundary in the Mediterranean sequences.