Geology uncovers a new terrestrial secret : there is a lost continent hidden beneath southern Europe, and scientists have created the most detailed reconstruction yet.
The lost continent, called “Greater Adria” arose about 240 million years ago , after it separated from Gondwana, a southern supercontinent made up of Africa, Antarctica, South America, Australia, and other large landmasses.
Greater Adria was a large continent , stretching from what are now the Alps to Iran, but not everything was above water. That means it likely made up a chain of islands or archipelagos, according to Douwe van Hinsbergen, chair of global tectonics and paleogeography in the Department of Earth Sciences at Utrecht University in the Netherlands and leader of the study published in the journal Nature. .
Researchers spent a decade collecting and analyzing rocks that used to be part of this ancient continent. The mountain belts where these rocks of Greater Adria are found cover some 30 different countries : everything is gathered in the same image.
The Earth is covered with large tectonic plates that move relative to each other. Grand Adria belonged to the African tectonic plate (but was not part of the African continent, since there was an ocean between them), which slowly slid beneath the Eurasian tectonic plate, in what is now southern Europe.
Between 100 and 120 million years ago, the Greater Adria continent crashed into Europa and began to plunge beneath it but some of the rocks were too light and therefore did not sink into the Earth’s mantle. Instead, they were “scraped”, in a way similar to what happens when a person puts their arm under a table and then slowly moves it underneath: the sleeve wrinkles; Well, the same thing happened to the rocks. This wrinkling process formed mountain ranges like the Alps. He also kept these ancient rocks locked in place, where geologists could find them.
The experts observed the orientation of small magnetic minerals formed by primitive bacteria in these rocks. Bacteria produce these magnetic particles to orient themselves with the Earth’s magnetic field. When the bacteria die, the magnetic minerals remain in the sediment. Over time, the sediment around them turns to rock, freezing them in the orientation they were hundreds of millions of years ago. Geologists found that in many of these regions, the rocks had undergone large rotations.
In addition, the team led by Hinsbergen rebuilt large rocks that used to be close together , such as in a volcano belt or a large coral reef. Imagine a puzzle of colossal size. From there, they used software to create detailed maps of the ancient continent and confirmed that it was moving north while turning slightly, before colliding with Europe.
Understanding this lost continent is a puzzle that has been – for now – ten years in the making, and things are not yet fully resolved. How to name the ancient land mass has even been debated. But its existence is a sign that history can still find its way into unexpected places, and it’s a reminder that while our own continents may seem settled, our own landmasses are still moving today.
Referencia: Daily briefing: The lost continent that lies submerged below Europe Nature ( IF 43.070 ) Pub Date: 2019-09-09 , DOI: 10.1038/d41586-019-02702-5
