Geologists from several countries, when investigating all mountain ranges from Spain to Iran in detail for ten years, have found evidence of the existence of the lost continent of Great adria, a piece of continental crust the size of Greenland, which once separated from northern Africa, sank into the mantle of the earth beneath southern Europe.
The only visible remains of that lost continent are the limestone rocks that can be found in the mountain ranges of southern Europe.
250 million years later, the history of Gran Adria has been reconstructed step by step by a team of geologists from the universities of Utrecht, Oslo and the ETH Geophysics Institute in Zurich. As explained by the principal investigator Douwe van Hinsbergen, Professor of Global Tectonics and Paleogeography at the University of Utrecht:
Most of the mountain chains we investigated originated from a single continent that separated from North Africa over 200 million years ago. The only remaining part of this continent is a strip that runs from Turin through the Adriatic Sea to the heel of the boot that forms Italy.
Grand Adria became a separate entity when it separated from the southern supercontinent of Gondwana (which included what is now Africa, South America, Australia, Antarctica, the Indian subcontinent and the Arabian Peninsula) about 240 million years ago and began to move north. About 140 million years ago, it was a landmass the size of Greenland, largely submerged in a tropical sea, where sediments accumulated and slowly turned into rocks.
Then, when it collided with what is now Europe between 100 million and 120 million years ago, it shattered and was pushed under that continent. Only a fraction of the rocks of the Grand Adria, scraped in the collision, remained on Earth's surface for geologists to discover. These scrapes are now the mountain belts of the Apennines, parts of the Alps, the Balkans, Greece and Turkey.
But it has not been easy: the study had to face an additional complication: the rocks of Gran Adria are scattered throughout more than 30 countries, ranging from a strip of the Iberian peninsula to Iran. And the Mediterranean region is geologically among the most complex regions on Earth.