If you are thinking about taking a trip to Mauritius, you might want to add something new to your itinerary: looking for the “lost continent.” Scientists have now confirmed that Mauritius was once part of a much larger “supercontinent” named Gondwana. Now, it is the only part left.
Mauritius is an island and, suspiciously, there aren’t any rocks on the island that are older than nine million years. So where did it come from?
Scientists believe that it was once part of a lost continent that disappeared into the Indian Ocean some 200 million years ago, according to the dating they have been able to do. Mauritius was once a piece of the crust.
We knew that the continents were all once fused together, but to know that some just disappeared may change the way we think about land formations.
“We are studying the break-up process of the continents, in order to understand the geological history of the planet,” said Professor Lewis Ashwal from the University of the Witwatersrand in South Africa.
In order to conclude what had been suspected for years, scientists looked at the rocks left over from volcanic eruptions and traced the levels of zircon in them. Ashwal and team found that the remnants of the mineral were likely far too old to belong on Mauritius, but it was plentiful there.
“Earth is made up of two parts – continents, which are old, and oceans, which are “young”. 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,” said Ashwal.
“Mauritius is an island, and there is no rock older than nine million years old on the island. However, by studying the rocks on the island, we have found zircons that are as old as three billion years,” he said.
Zircons are minerals that we see mainly in granites from the continents. They have a particular make-up that includes uranium, thorium and lead. It also allows them to be dated accurately with little margin of error.
“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,” said Ashwell. This isn’t the first time that zircons have been found. In fact, in 2013 another study found them but they didn’t do a thorough job of explaining how it all got there.
“The fact that we found the ancient zircons in rock (six-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,” said Ashwal. He also suggests that there are many pieces of this continent hidden all over the area.