Interaction of down-slope and along-slope processes off Capo Vaticano (southern Tyrrhenian Sea, Italy), with particular reference on contourite-related landslides

The Late Quaternary architecture of the upper slope-shelf sector of the Calabro-Tyrrhenian continentalmargin off Capo Vaticano was reconstructed to decipher the interaction of along-slope and down-slope sedimentary processes, based on the analysis of very high-resolution single-channel seismic profiles and multibeam bathymetry. Both along-slope bottom currents and downslope gravity processes influenced the stratigraphic architecture of the margin during the last eustatic cycle, locally forming a mixed turbidite and contourite system. Along-slope processes formed elongated drifts located on the upper continental slope and outer shelf, while gravity-driven down-slope processes formed mass-transport deposits and turbidite systems with erosive channels, locally indenting the present-day shelf. Several slide events affected the elongated drifts and failure processes appear to be dominated by translational sliding that affect the upper 10–20 m of the stratigraphic record, with glide plains developed within contourite deposits. The most striking feature is the Capo Vaticano slide complex, which displays a large spatial coverage (area of about 18 km2), between ca −190 m and −500 m and is composed of several intersecting slide scars and overlapping deposits. These characteristics are peculiar for the Tyrrhenian continental margins, where slide events developed in open-slope areas are usually less complex and smaller in size. This would indicate that high sedimentation rates and occurrence of contourite deposits can represent a preconditioning factor for medium-large scale slope instability on the Tyrrhenian margins.