Timing of arrival of the Danube to the Black Sea: Provenance of sediments from DSDP site 380/380A

Abstract

Estimates for the timing of the arrival of Danube sediment to the Black Sea range from Messinian to Pleistocene; the river is currently the largest sediment contributor, supplying 88 MT/yr. We identify two changes in siltstone provenance-sensitive heavy mineral abundances at DSDP site 380/380A in the southwest Black Sea. Comparison with modern river sediment compositions indicates that siltstones above 571.5 mbsf (metres below sea floor) were supplied by the Danube, while sediments below 651.0 m were sourced by other supply systems. Palaeo-magnetic, 40Ar/39Ar and biostratigraphic data reveal that the influx of Danube-supplied sediment to the southwest Black Sea began between 4.36 ± 0.19 Ma and 1 Ma ago (Zanclean–Calabrian). Our results provide an independent time constraint on palaeogeographic reconstructions of the Pannonian and Dacian basins, which acted as upstream sediment sinks, and suggest that significant volumes of Danube-supplied sediment only started to reach the Black Sea at least 1 Ma after the Messinian Salinity Crisis (5.971–5.33 Ma) had ended.