The Central Mediterranean

B ecause of their geologically young age and com-plex geological setting, central Mediterraneanshelves show a large variability in morphol-ogy (width, slope, unevenness), stratigraphy (differentthickness of depositional bodies resulting from the lastclimatic/eustatic cycle) and sedimentology (shelf-mudoffshore of the main river mouths, bioclastic sedimentin under-supplied areas). The overall morphology usuallyencompasses a well-defined shelf break as deep as 120mto 150 m; above this depth, a well-developed erosionalunconformity cutting across older deposits is present,overlaid by the depositional sequence formed in the last20,000 years during the last sea-level rise and the presenthighstand of sea level. The thickness of such a sequence ishighly variable, from many tens of meters offshore of themain rivers (e.g. the Po and Tiber) or in tectonically activeareas (e.g. the Ionian Sea), to a few decimeters on insularshelves or on uplifting regions with arid climates (e.g.Apulia and the volcanic islands of the Tyrrhenian Sea).Accordingly, the shelf is floored by detrital siliciclasticsediment in well-fed areas that show sandy shorelinesand muddy shelves with a mud line located at about20 m, and by bioclastic sand and silt in underfedareas.The morphology of the shelf is profoundly con-ditioned by the tectonic and sedimentary setting.In stable/uplifting and underfed areas, bedrock mayoutcrop and create a complex setting of shoals andpaleo-headlands. In subsiding and well-fed areas the shelfis usually flat, with a slope of a few tenths of a degree.