Originally, the island of Mauritius was thought to be the result of a series of volcanic eruptions around nine million years ago. While the age of its surface sands coincides with the series of eruptions, scientists uncovered minerals that are between nearly 600 million to two billion years old, leading them to reconsider the age and the origin of the mid-Indian Ocean island.
Scientists questioned the age of the island after noting an anomalously stronger field of gravity in the area, leading them to suspect that the landmass below could be denser and thicker than a typical island created by volcanoes.
Nestled off the eastern shore of Madagascar, Mauritius is now thought to be a remnant of prehistoric landmass connecting India and Madagascar – a slice of micro-continent now dubbed Mauritia. Scientists at the University of Oslo say Mauritius and other nearby islands stayed afloat when Madagascar and India drifted apart 60 million years ago.
They say that fragments of the ancient continental connection sunk below the remaining islands, and that zircon-rich sands must have washed upward to Mauritius’ beaches during more recent volcanic eruptions. Zircons are minerals based in continental crust that can be displaced in sand or granite over millions of years. Zircon is found everywhere, can survive erosion displacement and usually contain trace amounts of radioactive material; thusly, they serve as valuable materials for dating areas of rock throughout evolutionary periods.
Furthermore, remnants of non-gone micro-continent Mauritia seem to have had drifted over underwater volcanic hotspots that created the neighboring island of Reunion. Theses hotspots – or mantle plumes – soften tectonic plates which then break apart. While it is possible to trace the drifted remnants using model plate tectonics, scientists say the proof lies in seismic study of the continental region, which has yet to be conducted.