An Open-Air Geological Museum: The Dolomites and Their Evolution
South Tyrol is a true geological treasure chest, where nature has sculpted extraordinary landscapes through geological eras, tectonic movements, and climatic changes. The Dolomites, a UNESCO World Heritage Site, offer curious eyes an “open-air museum” where every mountain, rock, or gorge tells a story millions of years old. This geologically diverse environment — shaped by weather, rocks of different origins, and deep movements of the Earth’s crust — is one of the most fascinating in Europe.
Permian and Triassic: Between Fossils and Ancient Seas
The first geological layers of the Dolomites date back to the Permian period, around 270–280 million years ago. During this era, the first sedimentary layers formed, composed mainly of clastic and volcanic rocks (such as porphyry), creating the geological foundation upon which the Dolomites later developed.
It was during the Triassic period that the Dolomite mountains truly began to take shape. At that time, the area was submerged under a warm, shallow tropical sea, leading to the formation of coral reefs, carbonate cliffs, and dolomite rock — the material that gives the Dolomites their name.
Due to continuous uplift and subsidence of the terrain, it is now possible to find within the rocks traces of marine fossils such as corals, mollusks, and sponges — astonishing evidence of a submerged past.
A particularly important site to observe this stratification is the Bletterbach Gorge, also known as Gola del Rio delle Foglie.
Corno Bianco and Corno Nero: The Meeting of Two Worlds
One of the most striking geological phenomena can be seen between Corno Bianco and Corno Nero, at the boundary between the Dolomite and porphyry worlds. Here, the Dolomite chain abruptly meets the volcanic rock of the Lagorai range, characterized by darker hues.
The Passo degli Oclini, located between the two peaks, marks a clear divide visible to the naked eye: on one side the light sedimentary rocks of the Dolomites, on the other the reddish-brown porphyry rocks born of ancient volcanic eruptions. It is a contrast not only of colour but also of structure and resistance to weathering, giving rise to spectacular and highly distinctive landscapes.
San Cassiano and the Fossils of the Dolomites: A Glimpse into the Past of Life
There are several locations where the succession of geological eras can be clearly observed. One of the most spectacular is found on the slopes overlooking San Cassiano in Alta Badia. Here, the Dolomite formation of the Conturines, with the Varella and the Sasso di Santa Croce, towers above an older base of sedimentary rock, gently descending toward the meadows and the village below.
Thanks to weathering and landslides, these layers are now clearly visible and easily recognisable by their colour and granular structure. This area is particularly interesting because it represents a geo-zoological site: the ancient Dolomitic coral reefs have preserved numerous marine fossils, thanks to the nature of the rock that encased them for millions of years.
In the rock complex of San Cassiano, one can observe a gradual evolution of life forms — from the remains of small marine invertebrates to more recent traces of prehistoric fauna.
Curiosity: The Dolomite Rock
The name “Dolomites” comes from the mineral dolomite, itself named after the French geologist Déodat de Dolomieu, who first studied it in 1791. Dolomite is a sedimentary rock composed of double carbonate of calcium and magnesium, far more resistant to erosion than other limestone formations.
One of this rock’s unique features is that its chemical composition reflects light in a distinctive way, giving rise to the phenomenon known as “enrosadira”: an intense pink-orange glow visible at sunrise and especially at sunset, when the mountains seem to blaze in a dreamlike scene.
A Landscape Sculpted by Time
Walking among the Dolomites means not only immersing oneself in natural beauty but also travelling through time — across ancient tropical seas, volcanic eruptions, and titanic forces that have shaped the mountains as we see them today. Observing the contrast between Corno Bianco and Corno Nero or admiring fossils in the rocks of San Cassiano is like reading a history book carved in stone.
These areas, accessible through hiking trails and scenic routes, offer not only breathtaking views but also the chance to understand the origins of Earth and life itself — in a truly spectacular setting, unique in the world.