My first post about the Italian Dolomites described how the carbonate platforms formed from the hard parts of organisms living in shallow parts of a warm, tropical ocean (https://landscapes-revealed.net/trekking-through-an-ancient-sea-in-the-italian-dolomites/). The second post described other rock types in the Dolomites, namely igneous rocks and sedimentary rocks transported to the ocean from land (https://landscapes-revealed.net/not-all-of-the-rocks-in-the-italian-dolomites-are-dolomite/). Although created near sea level, the highest peaks of the Dolomites now reach elevations of nearly 3350 m (11,000 ft). How did these carbonate platforms that were “born” at sea level reach their current elevations? Like most other high mountains, the answer is compression—tectonic plates converging (i.e., moving toward each other) and pushing parts of Earth’s crust upward along faults.
Faults and folds formed by compression
When did this compression and uplift occur? In the first post (link above) I included a map showing how the continents were arranged in the Triassic Period when the Dolomites were formed. At that time, the Tethys Ocean separated Eurasia from Africa. Over time, the ocean shrunk because the Eurasian and Africa plates were converging, in the process compressing pre-existing rocks and creating the Alpine range that extends from France, in the west, to Austria, in the east. This mountain-building episode is called the Alpine Orogeny, and the Dolomites in Italy are the southeastern part of the vast Alpine range. If you look at my posts in September 2019, you will see three blogs describing the western part of the Alps in Switzerland. The Alps have formed in successive episodes during the Cenozoic Era (past 66 million years), and the Dolomites may still be slowly rising.
Elevation brings glaciers
Because of compression between the African and Eurasian plates, the Alps were uplifted to elevations high enough to receive abundant snow. If snow accumulates faster than it melts, it forms glaciers. During the last glacial maximum about 20,000 years ago, the Alps were covered with glaciers that have decreased in area since then. With anthropomorphic climate change now impacting our planet, the glaciers are shrinking even more rapidly. The so-called “queen of the Dolomites” glacier on Marmolada, the Dolomite’s highest mountain, could be completely gone in just a few years. The Dolomites are a popular place for skiing, hiking, and mountaineering. As explained in the caption to the next photo, these activities are becoming increasing dangerous.
Wonderful! The Italian Dolomites are spectacular! PaHope to go back sometime. Thanks for the culinary recommendations, too.
Wonderful Pat – thanks!