Seismic stratigraphy of upper Quaternary shallow-water contourite drifts in the Gulf of Taranto (Ionian Sea, southern Italy)

The occurrence of articulated seafloor morphology over continental shelf-upper slope environments, may resultin a significant change in the patterns and intensity of basin-scale thermohaline circulation during eustatic sealevelfluctuations. These changes may cause, in turn, erosion, deposition and/or transport of sediments at theseafloor, to form shallow-water contourite drifts. Here we investigate this process in the NW sector of the Gulf ofTaranto (Ionian Sea) during and following the Last Glacial Maximum (LGM), by integrating multibeam bathymetricdata, ultra-high resolution seismic-reflection data and gravity core data. Sea level fall caused subaerialexposure of the summit of the Amendolara Bank, forming a short-lived island off the eastern coast of Calabria,and also creating a narrow passageway between the island and the northern Calabria mainland. Integratedseismic-stratigraphic data show that Upper Quaternary shallow-water contourite drifts and associated erosionalfeatures locally formed both around the flanks of the Amendolara Bank (AMBK), and the continental shelf andupper slope off the Amendolara village. Contourite drifts are bounded at the bottom and at the top by two majorunconformities, indicating that the formation of the sediments drifts occurred between the onset of the LGM andthe GS-1/Younger Dryas event. The stratal architecture suggests the occurrence of various types of contouritedeposits, mostly represented by: a) Axial and lateral channel-patch drifts, and channel-related drifts along theincision to the NE of the AMBK; b) Sheeted drifts along the northeastern slope of the AMBK; c) Elongated driftsalong the continental shelf and upper slope off the coast of Amendolara village. Erosional features also developedon the south-eastern flank of the AMBK, where the Levantine Intermediate Water flows from the centralIonian Sea towards the Gulf of Taranto, until the present-day. Both processes and timing responsible for erosionof the seafloor and the formation of sediment drifts in the Gulf of Taranto may be similar to that occurred in theTyrrhenian margins during the Late Quaternary.