Dolomiti: journey through time

 

Geological time

 

Dolomitic lithogenesis

Like a great work of art sculpted by Mother Nature, the Dolomites were slowly formed during the long and drawn out geological time that we measure in millions of years. Before orogenesis caused the dolomitic rocks to tower at more than 3000m, nature made it possible for them to be formed.

In the very distant past, during the Triassic period (200-250 million years ago), sands, silts and slurries deposited on a tropical seabed and were transformed into rocks through the process of lithogenesis.  

Sedimentary rocks

Sedimentary rocks are formed by the accumulation of soft sediments such as mud and sand, which are progressively covered by more sediment and then transformed into rocks by means of pressure, increase in temperature, and the dissolution and/or precipitation of minerals from surrounding saline solutions. Sedimentary rocks are characterised by stratification.

Within this group there are the CONGLOMERATES, rocks formed from gravel, the SANDSTONES, rocks made from sandy sediments, and the PELITES, rocks made from loam and clay.

 

These rocks are all known as TERRIGENOUS rocks because they are made up of the products of erosion of dry land.

Then we have the CARBONATE rocks, namely LIMESTONES and DOLOMITES, which are almost always of marine origin and closely associated with the activity of small organisms like corals, molluscs, bryozoans, echinoderms, foraminifera, algae or sulphate-reducing bacteria.

Furthermore we have the MARLSTONES, carbonate rocks with significant clay content, and the EVAPORITES, rocks formed from saline deposits following the evaporation of seawater.

The Dolomite Mountains are made up of mainly sedimentary rocks, with each subgroup present in varying degrees.

Dolomitic orogenesis

During the Eocene period, between 40 and 50 million years ago, Africa and Europe continuously and progressively approached one another by a few centimetres a year.

Within a few million years, this short distance became kilometres and the Dolomites started to rise up.

Approximately 15-20 million years ago the sea beds were deformed, pushed out of the water and eventually rose to the height of mountains.

Dolomitic morphogenesis

The characteristic appearance and landscape that we know today came into being around 2-3 million years ago through the erosion and dismantling of rock segments caused by atmospheric agents.

After the last Ice Age, which started 80,000 years ago and ended 8,000-10,000 years ago, the indescribably beautiful landscape that we know today appeared. The final touches were added after the Ice Age.

The melting of the ice, which was sometimes up to 1,500m thick, created streams, torrents and rivers that dug up and carried away rock debris. Freed of ice, some slopes gave way and collapsed into the valley.