Geology and Geomorphology
The Marine Protected Area (MPA) of the Egadi Islands, with an extension of 53,992 hectares, is the largest marine reserve in the Mediterranean. Located in the Canal of Sicily, in front of the northwest coast of the Mother Island, it encompasses the Egadine archipelago which comprises the islands of Favignana, Levanzo and Marettimo and the islets of Formica and Maraone.
The archipelago falls on the western Sicily continental shelf and constitutes a fringe of the northern mountain range, of which it shares the same geological nature, as evidenced by the presence of vast calcarenitic deposits on most of the seabeds stretching between the islands of Favignana and Levanzo. The area of the platform on which the Archipelago stands, is characterized by erosive and depositional forms such as submerged cliffs, abrasion terraces, river valleys, paleobeaches and dunes, which testify the different phases of the last cycle of glacio-eustatic variation of the sea level. The morphology of the seabeds is quite irregular: wide flat areas alternate with very sharp tracts of seabed due to the presence not only of the islands, but also of steep paleocliffs, engraved valleys and depressions. In the first sector of the platform, closer to the Sicilian coast, there are Favignana and Levanzo, joined to the mainland by a slight depression, while in the second sector there is only the island of Marettimo, detached from the other islands by a canal 350 metres deep, which has kept this island steadily separate from the mainland since the Pliocene period. The canal is characterized by strong sea currents, caused by the large exchanges of water masses between the western and the eastern areas of the Mediterranean Sea.
The seabeds of the archipelago are characterized by medium-fine sands, with an organogenic component deriving from shells, and with a predominantly calcareous component resulting from the erosion of rocky outcrops. The zoning of the submerged vegetation of the entire archipelago is function of the nature of the substrate, of the intense hydrodynamism and of the light.
Surface caves and intense karst phenomena are the most expressive landscape aspect of the carbonatic nature of the substrates of the Egadi coastline. The elevated number of caves and galleries of the coastline corresponds to an equally developed underwater karst, with numerous submerged and semi submerged caves. The total area, at sea, of all the habitats with primary carbonate component is estimated at around 4,000 hectares.
The low light of the sheer seabeds, in many cases, favors the development of sciophilus concretioning and of coralligenous. The roughness of the limestones also increases the presence of meroplankton larvae as well as the formation of shelters occupied by rich endolithic fauna.
Around the Egadi Islands there are several rocky sandbars that have spectacular aspects both from an aesthetic point of view and for the exceptional animal population dominated by gorgonians and sponges