Evidence of a drowned “microcontinent” has been found in sand grains from the beaches of a small Indian Ocean island, scientists say.
A well-known tourist destination, Mauritius is located about 1,200 miles (2,000 kilometers) off the coast of Africa, east of Madagascar. Scientists think the tiny island formed some nine million years ago from cooling lava spewed by undersea volcanoes.
But recently, researchers have found sand grains on Mauritius that contain fragments of the mineral zircon that are far older than the island, between 660 million and about 2 billion years old.
In a new study, detailed in the current issue of the journal Nature Geoscience, scientists concluded that the older minerals once belonged to a now vanished landmass, tiny bits of which were dragged up to the surface during the formation of Mauritius.
When lava moved through continental material on the way towards the surface, they picked up a few rocks containing zircon, study co-author explained.
Most of these rocks probably disintegrated and melted due to the high temperatures of the lava but some grains of zircons survived and were frozen into the lava [during the eruption] and rolled down to form rocks on the Mauritian surface.
(Source: National Geographic)