Provenance of surface sediments along the southeastern Adriatic coast off Italy: An overview

• Multi-proxy sediment provenance study from the Adriatic mud belt.
• Ce/Ni and Zr/Cr can be used as sediment provenance indicators.
• Terrestrial OM and sediments from the Adriatic are transported to Gallipoli shelf.
• Sediments in the western Gulf of Taranto have a more local provenance.

Multi-proxy studies are necessary to understand sediment composition and related provenance on continental shelfs. Here it is shown that the spatial distribution of geochemical composition and grain size for surface sediments along the southeastern Italian coast is related to provenance and mechanisms influencing sediment pathways. A northern Adriatic/Italian provenance can be distinguished from a southern Apennine river source. This is done independent of grain size using the element ratios Ce/Ni and Zr/Cr. Furthermore, the origin of organic matter is determined using bulk carbon isotopes and the C/N ratio. Integrating these results with those from complementary studies on δ18O and δ13C of Globigerinoides ruber (white), the BIT index, stable isotopes of plant waxes and dinoflagellate cyst distribution from the same set of samples reveals that:
• Sediments from the northwestern Adriatic are transported as far southward as the Gallipoli shelf (eastern Gulf of Taranto) by the Western Adriatic Current (WAC)
• Along the WAC, there is a consistent southward decrease in Po river/northern Apennines provenance and a concomitant decrease in terrestrial (soil) organic matter (OM), whereas the percentage of marine OM increases.
• The provenance for Gallipoli shelf sediments is for ∼80% attributed to Po River/northern Apennines sources and for ∼20% to southern Italian sources.
• OM in the eastern Gulf of Taranto contains more marine OM than other areas within the WAC, whereas OM and sediments from the western part of the Gulf of Taranto have a more local, riverine provenance.