Submerged and emerged archeology

The research carried out on set structural geology and geomorphology of the coast of Palermo, show an evolution linked to the interaction of geological change glacial-eustatic sea level with the tectonic movements that occurred in the Pliocene-Pleistocene.

In the area there is a bedrock consists mainly of carbonate and terrigenous successions aged the Late Triassic. and the Miocene, belonging to paleodomini Panormide and Imerese. These units are involved in tectonic structures related to training late Cenozoic chain Sicilian. These lands are covered in unconformity deposits calcarenitic and sandy-pelitic Quaternary. These deposits occupy depressions coastal Isola delle Femmine and Sferracavallo, presenting subhorizontal or slightly inclined faults towards the sea.

Since the end of the Miocene the area has been affected by extensional tectonic processes, connected with the opening of the southern Tyrrhenian basin, and by episodes of compression that resulted in reversal of tectonic structures.

The substrate is displaced by fault systems oriented north-south and east-west. The geological-structural changes in the area and the glacio-eustatic sea level have affected the evolution of the areas emerged around the continental margin and in particular platform.

Along the coast there are several morphotypes coasts: high and rocky coast, in the stretch between Capo Gallo and Punta Barcarello; low and rocky coast with ripe and with high cliffs, the section between Sferracavallo and Isle of females.

The coastal plains of Isola delle femmine and Sferracavallo are carved from various orders of marine terraces located on sea level at different altitudes (+2 -3 m; m + 10-15 + 20-25 m; + 50-60 m) witness the phases of the Pleistocene marine ingression.

Studies carried out on the continental shelf and upper slope showed an eroded bedrock at the top, correlated with the Meso-Cenozoic carbonate sequences outcropping in Monti di Palermo. Unconformably on the substrate it is a sedimentary sequence of Pliocene-Pleistocene age, truncated upwards from a surface of erosion related to the last drop glacioeustatico sea level. Finally, there are deposits of lateral thickness very variable, accumulated during the last episode of low stationing the sea level and during the subsequent ascent and stationing high. The continental shelf in front of the AMP is very extended, its width is between 6 and 8 km. This reduced size and the high slope of the surface of the seabed, which in some places reaches 1, 5 tilt, are due to the young age of the margin and the tectonics, also testified by gravitational instability present along the margin.

The edge of the continental shelf is located at a depth of about 140-150 m. It is presented in progradation, with the exception of the areas corresponding to the high structural, where emerges the bedrock, and the stretches where the board is engraved by the heads of the numerous canyons present in the upper slope.

And ‘possible to divide the continental shelf in an area inside and one outside, separated by a convex slope break at the depth of about -60 m. The continental shelf internal 0 to -60 m which includes all AMP, is characterized in places surfacing from the carbonate bedrock.

The outer part of the continental shelf is characterized by sandy-pelitic deposits, prograding; the bedrock, although shallow, rarely emerges. The last swing glacioeustatica sea level has produced several morphological elements, both erosive depositional. In the outdoor deck were found beach rocks in shares – 75 m, -85 m, -95 m, me -105 -120 m. In the inner platform are observed broken concave slope, at depths of -8 m, -15 m, -35 I -53 m, at the base are associated platforms abrasion and cuts due to subaerial erosion.

The presence of these morphological elements within the AMP is an important factor for the interest of the underwater landscape biological variability hosting. In fact, the carbonate bedrock outcropping with all its forms (cliffs, steps, platforms abrasion, caves etc.) is the implant of some of the most important habitats of the MPA (sidewalk vermeti; posidonieto; pre-coral, coral, etc.).