Contrasting Mediterranean funds
No point of the island of Beauty is distant of more than forty kilometers from the Mediterranean. Corsica is surrounded by a coastal plateau of unequal width: about twenty kilometers on the side of Aléria, while around the mountainous edge of the Cape, it is of an extreme narrowness. The underwater reliefs reproduce the terrestrial eminences in an inverted way, as in a mirror. This submarine continental plain descends more or less progressively to a depth of 150 m to 200 m, then drops abruptly to 1,000 m when the submarine base on which the whole island rests disappears. The submarine plain is divided into four groups: the part closest to the coast, 10 to 20 meters deep, made of sand, pebbles and rocks; a part whose depth gradually reaches 40 meters: it is the eelgrass zone on which a meadow of green algae extends not uniformly; another one, even deeper (up to 80 meters) in which coral grows; a last one, made of mud, which goes down to the limits of the crystalline base.
A heterogeneous coastline
For those who don't go scuba diving, the Corsican coastline offers a real diversity of situations that are one of the major attractions of tourism on the island. The vast sandy strip of the eastern coast, sometimes interspersed with ponds and lagoons, offers beautiful beaches with the graceful curves of its dunes, reminiscent of the Languedoc coastline. The southern and western coasts are so indented that, in the past, they could only be reached by boat! There are large promontories reminiscent of Finistère, and deep inlets where towns have developed: the gulfs of Propriano, Ajaccio and Porto. Higher up, the coast becomes gentler. The coastline remains highly fragmented, however, having been attacked by the sea during various Quaternary transgressions. The landscape sometimes resembles that of the Breton or Moorish coasts. In the estuaries around Figari or in the bay of Porto-Vecchio, you can even admire real rias! Northern Corsica is famous for the gentle landscapes of Balagne and the desolate Agriates region. Their coasts are punctuated by small coves topped by promontories delicately sculpted by erosion. The Cap Corse peninsula offers a much more rugged and wild terrain.
Corsican beaches are rightly considered among the most beautiful in the world. There are fine sandy beaches such as Saleccia,Ostriconi and Calvi, as well as pebbled and rock-encrusted beaches around Porto. For long beaches stretching as far as the eye can see, head for the east coast.
Lakes and marshes, reservoirs of biodiversity
Corsica is home to over thirty lakes of glacial origin, dating back as far as minus 14,000 years, with remarkable heritage value from both landscape and ecological points of view. Most of them are located in the high mountains, the highest at 2,442 m altitude. They are mainly found in the Cinto, Rotondo, Monte d'Oro and Renoso massifs.
Many of Corsica's marshes, whether of natural origin or the result of human transformation, are listed and protected as reservoirs of biodiversity, home to remarkable and endangered plant species, as well as the bird and fish species that breed and thrive there. In Corsica, four of these are recognized as being of international importance: the Biguglia, Urbino and Palo ponds, and the Tre Padule temporary ponds in Suartone.
A special geological history
To understand the geological formation of this mineral mass, we need to go back to the origins of the Earth: in the Precambrian era, the western and southern parts of the island must have been united with the Provençal massif of the Maures, as well as with the western Pyrenees. Indeed, the same crystalline rocks are found in all three areas: essentially granite. It is in the Hercynian massif of Ajaccio, which forms a vast block stretching from Solenzara in the south to Ile-Rousse in the north, that the highest and steepest reliefs are to be found, with resistant rocks and sharp peaks. Quaternary glaciers did not spread to the plains, but they did help sculpt the peaks. These include, in addition to Cinto and its satellites, the Rotondo (2,695 m) and Monte d'Oro (2,391 m) groups in the center of the island, and Incudine (2,136 m) in the south. To the north-west of this complex, a vast band of coalfields can be found: these are essentially Upper Carboniferous deposits.
In a vast arc around Bastia, we find lustrous schists similar to those found in Piedmont. Their altitude barely exceeds 1,500 m. These are essentially Tertiary soils of sedimentary origin, the result of deposits caused by the various seas that have covered these regions over geological time. These lands were raised by the vast tectonic movements that gave rise to the neighbouring Alps. The fault movements that created Corsica's relief are concentric: they follow a south-north direction at Cap Corse. Then, at the southern limit of this schistose part of Corsica, on the edge of the Aléria plain, they gradually dip along a west-northwest axis.
Between these two unequal blocks, which delimit two main regions, runs a transitional strip. The town of Corte lies on this axis, which winds from the shores between the Reginu and Ostriconi rivers in the north to Solenzara in the south. Thus, around the peaks of Rotundu, Monte d'Oro and Renoso in the center, and Incudine further south, we can observe a vast depression. The soils are Tertiary and immediately recognizable by their contrast with the granite mountains!
