The University of the Witwatersrand says a team of scientists have discovered the remnants of what they believe is a continent which was lost when the supercontinent of Gondwana split over 200 million years ago.
Pieces of a lava-coated crust of the “lost continent” were discovered under the Indian Ocean of Mauritius.
Wits geologist Lewis Ashwal‚ Michael Wiedenbeck of the German Research Centre for Geosciences and Trong Torsvik of the University of Oslo have studied zircon found from the piece of the continent.
Zircon is a mineral which is discharged by lava during volcanic eruptions.
With the oldest rocks on Mauritius believed to be around nine billion years old‚ the newly discovered zircons are around three billion years old‚ suggesting that these are far too old to belong to the island of Mauritius.
“Earth is made up of two parts – continents‚ which are old‚ and oceans‚ which are ‘young’‚” explained Ashwal‚ who is the lead author on the paper ‘Archaean zircons in Miocene oceanic hotspot rocks establish ancient continental crust beneath Mauritius’‚ which was published in the Nature Communications journal.
“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 said.
Sceptics have however‚ criticised the findings‚ with others arguing that the mineral could have separated from Mauritius by being blown by the wind or being carried on vehicle tyres of those treading on the island.
Ashwal has dismissed these claims.
“The fact that we found the ancient zircons in rock (6-million-year-old trachyte)‚ corroborates the previous study and refutes any suggestion of wind-blown‚ wave-transported or pumice-rafted zircons for explaining the earlier results‚” he said.
“According to the new results‚ this break-up 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‚” Ashwal added.