The physical and morphological characters of this particular region create many contrasting features: from harsh peaks to round hills, from wood-covered crests to small plains, from steep, narrow valleys to open spaces on the highest mountains, from deep-red rocks to white cliffs facing the sea.
The relief of the area can be divided into distinct morphological groups, characteristic of different parts of Ogliastra.
- The limestone shapes of “Supramonte” in Baunei and Urzulei (photo), with Karst phenomena which reach as far as the coastal cliffs.
- The dolomitic limestone phenomena known as “Tacchus”, which rise above Jerzu, Ulassai, Osini and Gairo.
- The porphyry and granite of the mountains in Arzana, Villagrande and Talana, which form the Ogliastra side of the Gennargentu massif.
The highest peak of this range, Punta La Marmora (1,834m), is in the town limits of Arzana.
These orographical conditions have created some extremely interesting phenomena:
- The “Gola di Gorropu” (photo: P. Rinaldi), the deepest canyon in Italy (and perhaps even in Europe), bordered by steep rock faces up to 500m high.
- The sandy bays, nestled between high cliffs, where the so-called “codulas” emerge from the inland hills. Some of the most charming bays include, from south to north: Cala Goloritze’, Cala Mariolu, Cala Biriola, Cala Sisine and Cala Ilune.
- The “guglie” – stone pinnacles which contrast with sheer cliff faces – one of the most spectacular ones is called Punta Caroddi (148 m), an impressive natural monument which overhangs the bay at Goloritze’.
- Karst phenomena which have created ravines, gorges, hollows and breaches which cut into the surface of the earth: an interesting example can be found in the countryside, near Baunei. The “Voragine (or chasm) del Golgo” or “Su Sterru” is a 294 m deep doline.
- Caves. Many examples can be found in the area, all of great speleological interest. Examples include “Su Marmuri” at Ulassai, “Taquisara” at Gairo and “Sa domo ‘e s’orcu” near Urzulei, where several archaeological finds from the Nuraghic period have been found.
- The areas of “Tacchus” inland, (the most impressive one is “Perda Liana”). Standing at 1,293m, it is a sort of limestone tower, rich in fossil material and of great geomorphological interest.
? Codulas: Narrow canyons carved in the rocks by seasonal water streams. You can reach the sea from the mountains following these canyons, which are often dry.
? Tacchus: Large limestone outcrops, characterised by steep slopes and peaks covered by thick vegetation (holm-oaks, junipers, strawberry-trees and hollies).