One of the lost continents, probably left untraced after the break up of the super continent Gondwana 200 million years ago was found under the island of Mauritius in the Indian Ocean.
Covered by volcanic lava over the period of time, it looked like a small piece of ancient continent that scientists believe could be broken off from Madagaskar during the time when Africa, India, Australia and Antarctica split up from the Gondwanaland.
Prof. Lewis Ashwal from University of the Witwatersrand in South Africa who led the team said remnants of the mineral, zircon, found in rocks beneath the lava were far too old to belong to the young island of Mauritius.
Zircons are minerals which contain traces of uranium, thorium and lead, that survive geological process and provide a rich record of geological date of ancient rocks accurately.
“On the continents you find rocks that are over four billion years old, but you find nothing like that in the oceans, as this is where new rocks are formed,” he added. There is no rock older than 9 million years old on the Mauritius island which has merely 3 million years old rocks, he explained.
Rejecting past explanations that zircons in these rocks could have been a result of wind-blown, wave-transported or pumice-rafted zircons, he said, “According to the new results, this breakup did not involve a simple splitting of the ancient super-continent of Gondwana, but rather, a complex splintering took place with fragments of continental crust of variable sizes left adrift within the evolving Indian Ocean basin.”
The rock minerals point out an older Proterozoic or even Archaean components, as these zircons yield Archaean U–Pb ages, confirming the existence of a fragment of Precambrian continental crust beneath Mauritius, they said.
“We propose here that Mauritius and other Mauritian continental fragments are dominantly underlain by Archaean continental crust, and that these originally formed part of the ancient nucleus of Madagascar and India,” they said in their study.
The study was published in the journal Nature Communications.