03/04/2026
Sardinia is one of the oldest continental blocks in the Mediterranean.
The so-called Sardinian-Corsican block is a fragment of European crust that separated from the Iberian Peninsula around 20 million years ago, rotating into its current position.
Part of this block is made up of carbonate rocks — limestones and dolomites deposited in tropical marine environments between the Cambrian and the Jurassic, roughly 540 to 150 million years ago.
These rocks are soluble: rainwater absorbs atmospheric CO₂ to form carbonic acid, weak but sufficient to dissolve calcium carbonate along fractures and joints in the rock.
The process is called karstification. It operates on geological timescales: millions of years of percolation widen fractures into conduits, conduits into passages, passages into complex systems.
When the water table drops or sea level changes, some passages drain. Others remain flooded — they become the submerged caves we explore.
In Sardinia, karstification is particularly developed in the Palaeozoic limestone areas of the Iglesiente and Sulcis, and in the Mesozoic formations around Dorgali, Orosei, and the Nurra. Old, compact, fractured rock. Tens of millions of years of dissolution.
Not by chance. The result of a specific lithology, sufficient rainfall, and geological time long enough to carve what we explore today.
