A team of researchers says they've discovered evidence of a lost continent buried deep in the Indian Ocean under the island of Mauritius.
In a paper published this week in the scientific journal , researchers make a case for the existence of a piece of crust that splintered with the break-up of the supercontinent Gondwana, which started about 200 million years ago.
To understand the significance of the discovery requires first understanding the earth's prehistoric topography.
Gondwanaland contained rocks as old as 3.6 billion years old before it split into what are now the continents of Africa, South America, Antarctica, India and Australia.
As the continent began to spread apart, it left pieces of land behind, one of which is thought to have become covered in volcanic lava before sinking under what is now Mauritius.
For their study, lead scientist Lewis Ashwal of the University of the Witwatersrand in South Africa, looked at the mineral zircon found in rocks spewed up by lava during volcanic eruptions to determine their age.
But what he found was that some remnants were as old as 3 billion years old -- much too old to belong to the island of Mauritius, where there is no rock older than 9 million years old.
"The fact that we have found zircons of this age proves that there are much older crustal materials under Mauritius that could only have originated from a continent," says Ashwal.
The Nature study corroborates a separate 2013 report, in which researchers also found traces of the mineral in beach sand.
But while critics pointed out that the mineral could have been carried in by the wind or have been carried onto the island by human activity, Ashwal claims that his study offers definitive proof of the existence of a lost continent.
"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."
