Fragments of an ancient micro-continent could be preserved beneath the floor of the Indian Ocean, reports a study published online this week in Nature Geoscience. The findings suggest that the micro-continent broke up and dispersed as the Indian Ocean basin grew.

Trond Torsvik and colleagues examined the composition of beach sands on the island of Mauritius in the western Indian Ocean. The sands formed from the erosion of volcanic rocks that erupted 9 million years ago, yet the researchers found within the sands ancient zircon minerals, aged between 660 and 1,970 million years old. They suggest that the zircon points to the existence of fragments of an ancient micro-continent beneath the island, pieces of which were brought to the surface by recent volcanic activity.