19°0'0"E 18°E 17°E 16°E 15°E 14°E 13°E 45°N 44°N 43°N 42°N 41°N 40°N A B A -200 -1200 -500 (m) A B Slope section ADW NAdDW LIW -0 Deep water production area NAdDW LIW ADW 0 100 200 50 km Ionian Sea Tyrrhenian Sea Italy Adriatic Sea Me dit err an ea n Se a Adriatic Sea Pelagosa sill Otranto Strait Hotspot Ecosystem Research and Man's Impact On European Seas Final meeting 2012 Faro, Portugal, 11-14 September 2012 CONSIGLIO NAZIONALE DELLE RICERCHE Istituto di Scienze Marine 6 km N SE120 -850 -900 -950 -1000 m SE120 1 km E W E The reshaping of the South West Adriatic Margin by pervasive dense shelf water cascading A GIS-based methodology for quantitative geomorphological mapping Foglini F., Trincardi F., Campiani E. Istituto di Scienze Marine ISMAR – CNR, Bologna, Italy CONCLUSION 1. The morphological analysis suggests that the entire margin is undergoing a thorough re-shaping driven by the impact of a particular class of seasonally modulated bottom-trapped density cur- rents; 2. All these erosional and depositional features document how the dense shelf water cascading interacts with the pre- existing and markedly differentiated morphologies and sediment distribution; 3. The analysis of the bedform orienta- tion and spatial distribution make pos- sible to infer the pathway of the downslope-cascading bottom-currents. Trincardi, F., Foglini, F., Verdicchio, G., Asioli, A., Correggiari A., Minisini, D., Piva, A., Remia, A., Ridente, D., Taviani, M. 2007. The impact of cascading currents on the Bari Canyon System, SW-Adriatic Margin (Central Mediterranean). Mar. Geol., 246, Issues 2-4: 208-230. Trincardi, F., G. Verdicchio, and S. Miserocchi (2007), Seafloor evidence for the interaction between cascading and along-slope bottom water masse. J. Geophys. Res., 112, F03011, Verdicchio, G., Trincardi, F., 2006. Short-distance variability inabyssal bed-forms along the Southwestern Adriatic Margin (Central Mediterranean). Mar. Geol. 234: 271–292. The Southwest Adriatic Margin includes a steep and morphologi- cally complex continental slope stretching about 400 km from the Pelagosa sill to the Otranto strait. The area has been investigated through multibeam surveys accompanied by high-resolution seismic stratigraphic surveys investigating glacial and post-glacial deposits. After the end of the last glacial sea level low stand the North Adri- atic shallow shelf became progressively drowned as a consequence of the eustatic rise. Through its progressive drowning, this region became a shallow shelf and one of the Mediterranean key sites for the formation of dense shelf waters through wind-forced winter cooling. The dense waters formed through this process move to the south, along the western side of the Adriatic, and reach the South Adriatic slope across which they cascade hugging the sea floor and generat- ing a myriad of depositional and erosional effects such as: giant sediment drifts down to 1200m water depth, muddy and sandy sedi- ment waves, comet marks against pre-existing slide blocks, furrow fields, large scours at the shelf edge and large erosional moats against major morphological barriers. The fields of dominantly muddy sediment waves have a patchy distribution and appear to reflect the interaction between the down-slope path of the dense water and the presence of both morphological constraints to acceler- ate the flows and mobile sediment to be casted into wavy bedforms. Simplified intermediate- and deep-water circulation in the Adriatic Sea: NAdDW=North Adriatic Dense Water; LIW=Levantine Intermediate Water; ADW=Adriatic Dense Water. RESULTS Mud Wave fields Field A: The wave crests vary from slightly sinuous to bifurcated, with general ori- entation NE-SW. The wave heights are 10-30 m and the wavelengths in the region of 700-1300 m with wave crests up to 5500 m long. In cross section the sediment waves are asymmetric, with the depositional flank facing obliquely upslope. The opposite, downslope, flank is markedly less depositional