There is indeed under Mauritius a microcontinent. If a study dating from 2013 already asserted the existence, this discovery was confirmed by the analysis of zircon samples from the depths of the island and rejected during volcanic eruptions.
The minerals studied would indeed be 2.5 to 3 billion years old. But on the island, the oldest rocks are 9 million years old. This is what researchers put forward, whose study was published this Tuesday in the scientific journal Nature Communications.
First conclusions criticized
The zircon on which the specialists based their work was encrusted in volcanic rock. A detail that “refutes any suggestions of zircons blown by the wind or carried by the waves,” says one of the co-authors of the study, Lewis Ashwal.
In 2013, the conclusions of the first researchers who mentioned the submarine continent had indeed been criticized by critics who believed that the minerals analyzed, found in sand on beaches, could come from elsewhere.
The microcontinent would have appeared in the Jurassic era
“There is a lot of ancient material under Mauritius and it can only come from one continent. Our results thus demonstrate the existence of an ancient continental crust under this island “, can now affirm the scientist. Called Mauritia, the microcontinent would have appeared in the Jurassic era (from -200 to -145 million years ago).
It is actually several pieces immersed in different areas of the Indian Ocean. “When India separated from Africa, fragments of continental crust of different sizes were left behind and drifted into the changing Indian Ocean,” Lewis Ashwal argues.
Over time, lava would have covered these masses, making them invisible and undetectable for a long time. The discovery of Mauritia gives the passage to specialists hope to be able to rely on new information to better understand the history of continental drift.