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The Bari Canyon System dissects the slope of the Southwestern Adriatic Margin from the shelf edge to the base of slope. The Bari Canyon System is a complex feature showing evidence of seafloor instability through repeated mass transport events up to very recent times. The location and geomorphology of the canyon system is controlled by the growth of a suite of gentle anticlines superimposed to a long term tectonic tilt of the margin induced by the uplift of the Apulian swell (onshore) during the last 500 ky. The margin tilt, together with the progressive margin progradation into steeper slope regions, favoured the potential instability of the slope. This instability likely represents a key predisposing factor leading to the formation of the Bari Canyon System. The Bari Canyon System displays three heads, comprised in a crescent-shaped region, and two main E-W trending conduits almost parallel to each other. Side scan sonar mosaics show a canyon floor with high backscatter corresponding to acoustically transparent deposits on Chirp sonar seismic profiles. This evidence suggests a markedly erosional canyon floor with coarse sediment from failed masses which deposited in very recent times, as indicated by the absence of draped sediment at the seafloor. A peculiar characteristic of the Bari Canyon System is its marked asymmetry: the left-hand canyon walls dip 5°, while the rigth-hand walls dip as much as 14°. This asymmetry allows strong bottom currents (up to 60 cm/s), flowing along slope from the North, to enter the canyon and interact with the complex topography. These interaction generates four main sedimentary features: a) bottom current deposits, representing sediment drifts exclusively distributed upcurrent on pre-existing morphologic irregularities ; b) mass wasting deposits, generally not-buried in the canyon thalwegs and gradually buried toward deeper waters the base of the slope; c) turbidite deposits, including a channel-levee complex overhanging on the canyon floors; and d) erosional areas, such as gullies along canyon walls and furrowed patches close to the canyon floor. Preliminary stratigraphic and biostratigraphic work on piston cores allow to infer a Last Glacial Maximum (LGM) age to the buried mass wasting deposits. Biostratigraphic data also indicate that sediment drifts have grown since the end of the LGM, likely, during at least part of the Holocene. The age determination of early phases of the canyon evolution are based on the presence of incised morphologies affecting Pleistocene regressive sequences on the shelfslope transition. These erosional features are part of the canyon heads that clearly cut through the deposits of the two most recent Pleistocene regressive sequences, which post-date the MIS 8 (230 ky). Thus, the whole data set suggests that the canyon system formed after MIS 8 (230 ky), that it became a major sediment conduit during the LGM lowstand, when mass failure deposits also accumulated at the base of the slope, and that the system is still active

The Southwestern Adriatic Margin (SAM) offshore Apulia is a key site to study bottom current activity and their effect on sedimentation. The SAM is impacted by the complex interaction of two southward-flowing bottom water masses: the cold North Adriatic dense Water (NAdDW), forming in the shallow northern Adriatic through cold wind forcing and winter heat loss, and the highly saline Levantine Intermediate Water (LIW), generated in the Eastern Mediterranean through intense evaporation and flowing along the slope in a depth range of 200-600 m. Chirp-sonar profiles, TOBI mosaics, multibeam data and sediment cores reveal distinctive sediment drifts types (elongated, plastered and isolated drifts along the SAM) and, in particular, extensive fields of sediment waves. Non-depositional and erosional features related to bottom current activity include moats, between the crest of sediment drifts and the steep upper slope, widespread upper-slope erosional areas and extensively furrowed areas, particularly where changes in slope orientation force the current circulation. Distribution, morphology and size of bottom-current features along the SAM results from an interaction between current regime and complex margin morphology, characterized by structural highs perpendicular to the slope contour, multiple slope incisions and extensive slide deposits (e.g. blocky slide deposits). Morphobatymetric and seismic stratigraphic data on the SAM evidence that bottom current deposits are best developed where the regional slope flattens seaward of a very steep, often erosional, upper slope. The roughness of the lower slope, in particular, seems to correlate with the complexity and decreasing size of the bottom current deposits. Like other land-locked basins, the Adriatic underwent dramatic paleogeographic and paleoceanographic re-arrangements during the Late Quaternary sea-level oscillations. Indeed, during the Last Glacial Maximum (LGM), most of the areas where NAdDW form today were subaerially exposed. Concurrently, during glacial times the LIW production was likely reduced or deepened compared to the present-day conditions. Seismic and cores data allow investigate the impact of changing current regime on late Quaternary slope deposits. These data show that during the glacial periods bottom current appear less intense than they appear during interglacial time. Other Mediterranean late-Quaternary contourite deposits are either in water depths compatible with the LIW, particularly in the case of shallow sill basins (e.g.: Sicily, Corsica Channel), or at the slope base reflecting the flow of Mediterranean deep waters. The SAM bottom-current deposits, instead, seems to record the changing interaction between these two distinctive bottom-hugging currents along a common pathway.