Traces of prehistory

From the XII Apostoli lodge to the Agostini lodge: discovering how the Dolomites were formed

When you get up close to the Brenta massif for the first time, you can’t help but notice that the rock consists of complex and intricate layers, one on top of the other, alternating between deep chasms and pinnacles with a vaguely conical shape. This entire rock formation is the result of a long process of sedimentation, which took place over millions of years.

This stage of the combined climbing and trekking route called the Via delle Normali will open your eyes to the geological aspect of the Dolomites, showing you how they were created and formed.

Before setting out on an excursion at altitude, plan your trip with care. If you are inexperienced or you intend to tackle a route graded as technically difficult, then consult an alpine or mountain guide. You should also contact the refuge warden in the area you’ll be visiting for the latest weather information and to discuss whether your route is advisable. Take prudent precautions, wear suitable clothing for your route, and remember to act responsibly in the mountains at all times.

Via delle Normali: the geology of the Dolomites

It begins at the XII Apostoli lodge

Your ascent starts at Pinzolo. After reaching the XII Apostoli lodge — easily done, including a stretch by chairlift — stop and admire the imposing mountain walls of Cima Tosa and Cima d’Ambiez, the first two peaks that you will climb. We recommend stopping at the Agostini mountain lodge on this first day of the expedition. Your route there will take you across one of the most panoramic points of the Brenta Dolomites, as well as one of the most important from a geological perspective.

From the XII Apostoli lodge, you will continue climbing over scree, a typical feature of the landscape that you will find in every stage as you approach the peaks.

Via delle Normali: the geology of the Dolomites

Stop for a close look at the rock

The Brenta mountains consist largely of Dolomite, a mineral found in limestone rock — rock formed by the sedimentation of marine organisms — which is susceptible to being eaten away by weather conditions, forming great scree cones at the base of the mountain walls.

Dolomite is formed by the conversion of limestone (Calcium carbonate - CaCO3), typical of the Prealps, into a double carbonate of calcium and magnesium CaMg(CO3)2 by replacement. This chemical process takes tens of thousands of years, and occurs exclusively in marine environments with high levels of salt and shallow seabeds or lake basins that were once open sea.

You must remember that the Dolomites were once similar to today’s Pacific atolls: islands surrounded by seabeds colonised by coral. The immense biodiversity of this environment included algae, molluscs and fish during the Permian period, 280 million years ago. When the organisms that lived in this warm environment died, their remains were deposited on the sea floor and, over millions of years, were transformed from sediment to rock.

If you walk towards the Agostini lodge along the “Castiglioni” Via Ferrata, you will notice that the rock beneath your feet seems to be full of holes and markings. Pick up a stone and look closely at it: all those tiny markings are what’s left of the ancient corals that once formed the atoll.

Via delle Normali: the geology of the Dolomites

The Garden of Fossils

If you are climbing from Val D'Ambiez on foot, you will come across the “Garden of Fossils” just below the Agostini lodge. This field of rock, cut through by karren — karstic cracks — is nothing short of an open-air geology museum. Keep your eyes peeled, because among all these random forms you may spot what looks like a large shell: a megalodon, a bivalve mollusc which lived between 200 and 410 million years ago, when the Alps had not even been formed yet.

Reflect for a moment on the fact that the first peak you are about to climb, Cima d’Ambiez, like the other Brenta peaks, is nothing other than what is left of the shallowest part of the long-ago basin, thrust to a height of 3,000 m by the tectonic forces that generated the Alps over a period of around 200 million years.

Via delle Normali

Via delle Normali

Published on 06/06/2023