Pre-Zanclean end of the Messinian Salinity Crisis: new evidence from central Mediterranean reference sections

The concept of a geologically instantaneous earliest Zanclean reflooding of the Mediterranean Basin after the Messinian drawdown has dominated geological thinking and is ingrained in the scientific literature. The base of the Trubi Formation in southern Italy, formally defined as the Zanclean Global Boundary Stratotype Section and Point (GSSP) at 5.33 Ma, has traditionally been considered as marking the marine reflooding of the Mediterranean. However, several studies provide evidence that marine reflooding occurred prior to the Zanclean GSSP, the most reliable of which comes from southern Calabria. Here, we show that the sedimentary coastal prism cropping out extensively immediately below the base of the Trubi Formation in this region and correlatable with the Arenazzolo Unit in Sicily contains a fully marine micropalaeontological association of calcareous nannofossils and dinoflagellate cysts, thus pointing to both a high sea-level and marine conditions before deposition of the Trubi Formation (i.e. in the latest Messinian).