Ancient microcontinent discovered in Indian Ocean

Scientists have discovered what could be the remains of a "Precambrian microcontinent" in the Indian Ocean area, after studying lava sands from beaches on Mauritius.

 

In the study published Sunday in the journal Nature Geoscience, the scientists looked at when and where the lava sands may have originated.

 

"On the basis of reinterpretation of marine geophysical data, we propose that Mauritia was separated from Madagascar and fragmented into a ribbon-like configuration by a series of mid-ocean ridge jumps during the opening of the Mascarene ocean basin between 83.5 and 61 million years ago," they said.

 

They also said the plume-related magmatic deposits may "have since covered Mauritia and potentially other continental fragments."

 

A separate article on National Public Radio (NPR) said the researchers found the lava sands contained zircon xenocrysts, which came from a Precambrian microcontinent dubbed "Mauritia."

 

Mauritia had been sandwiched between the land masses that make up the present-day Madagascar and India.

 

"It was all part of a supercontinent known as Rodinia that existed between 2 billion and 85 million years ago," it added.

 

The NPR report said scientists believe Mauritia was broke apart and disappeared under the sea as Rodinia was ripped apart due to plate tectonics.

 

It also quoted a British Broadcasting Co. report where study lead author Trond Torsvik said they examined dates to a nine-million-year-old eruption near the modern-day islands of Marion and Reunion that spewed much older material.

 

"We found zircons that we extracted from the beach sands, and these are something you typically find in a continental crust. They are very old in age," Torsvik said.

 

BBC quoted Torsvik as saying he believes pieces of Mauritia were buried under six miles of surface and spread over a swath of the Indian Ocean, though a small part may have survived.

 

He said the Seychelles is a piece of continental crust sitting in the middle of the Indian Ocean, but may have been sitting north of Madagascar before.

 

Also, he said it could have been "much bigger," and "there are many of these continental fragments that are spread around in the ocean." — TJD, GMA News