Scientists have confirmed the existence of a “lost continent” under the island of Mauritius in the Indian Ocean, which remained after the collapse of the supercontinent Gondwana, which began 200 million years ago. A portion of the crust, which was subsequently covered with young lava from volcanic eruptions on the island, turned out to be a tiny piece of an ancient continent that separated from the island of Madagascar when Africa, India, Australia and Antarctica dispersed and formed the Indian Ocean.
“We are studying the process of the disintegration of the continents in order to understand the geological history of the planet,” says Lewis Ashwal, a geologist at the Witwatersrand University (Vitsa), the lead author of the work published in the prestigious journal Nature Communications.
Studying the mineral of zircon found in rocks rocked by volcanoes together with lava, Ashwal and his colleagues Michael Widenbeck of the German Research Center for Geography (GFZ) and Trond Thorswick of the University of Oslo, a visiting scientist at GFZ, discovered that the remains of this mineral were too old to belong to the island of Mauritius.
“The earth consists of two parts – continents that are old, and the oceans that are” young. ” On the continents, you can find breeds that are more than four billion years old, but you will not find anything like that in the ocean, because new breeds are formed there, “explains Ashwal. “Mauritius is an island, and there are no rocks older than 9 million years on the island. Nevertheless, by studying the rocks on the island, we found zirconas of 3 billion years old. “
Zircons are minerals that appear most often in continental granites. They contain traces of uranium, thorium and lead, and since they are well experienced in geological processes, they can also find a rich chronicle of geological processes and very accurately date.
“The fact that we found zirconas of this age proves that Mauritius has much older materials from the earth’s crust that could only have been born on the continent,” says Ashwal.
On this island is not the first time finding zircons in the age of billions of years. A study conducted in 2013 revealed traces of this mineral in beach sand. Nevertheless, this study received a lot of criticism, for example, on the topic of what this mineral could blow out by the wind or generally bring on automobile tires or scientists shoes.
“The fact that we found ancient zircons in the breed (6 million years old trachyte) reinforces the previous research and rejects any assumption of the possibility of being brought by the wind, waves or anything, as preliminary results showed,” says Ashwal.
Ashval suggests that there are many pieces of the “undiscovered continent” of various sizes, collectively called “Mauritius”, which are scattered throughout the Indian Ocean and remained from the disintegration of Gondwana. The new results show that this disintegration was not a simple splitting of the ancient supercontinent of Gondwana, but a complex fragmentation, when parts of the continental crust of various sizes were thrown to the mercy of the developing Indian Ocean basin.
The Gondwana supercontinent existed more than 200 million years ago and included breeds of 3.6 billion years old before being divided into what today is Africa, South America, Antarctica, India and Australia. The crushing occurred due to plate tectonics.