Magic Sheet 55 Table — Map (OpenData)

The sheet is located in the central part of the Tyrrhenian Sea, in the northern sector of the eastern edge of Sardinia and includes a stretch extending from Porto Cervo to Tanaunella. The sheet includes the northern sector of the continental shelf of the Basin of Olbia, an intra-scarped basin of the eastern edge of Sardinia. The sheet also covers part of the upper escarpment, up to depths of about 500 m. The continental escarpment has a maximum extension of about 20 km up to the shelf-break placed at about -120 m. In the innermost part of the platform, at depths between 60 and 75 m there are a series of morphologies attributable to fossil lagoon cords. These have an extension of about ten km and a relief with respect to the surrounding ground of about 10-15 m. In the distal part of the platform emerge reliefs of lithoid substrate, in some cases engraved by paleo-valley river. Fossil and currently submerged deltizi systems are located at shelf-break, in some cases in correspondence with canyon warheads. The canyons in the sheet are: the Mortorio, the Tavolara system, Olbia and the Posada system, which represents the main canyon of the north-eastern sector of Sardinia, and the only one currently connected to a river system. The Posada canyon system consists of 6 tributary canyons engraved on the platform that flow into a single branch in the escarpment, located about 1 100 m deep. CNR-ISMAR