Scientists who reported the discovery of remnants of an ancient continent under the Indian ocean island Mauritius have called for broader studies on the supercontinent Gondwana's split to decipher the linkages with the undiscovered micro-continent Mauritia.
Lewis Ashwal of the University of the Witwatersrand in South Africa and colleagues confirmed that the island nation Mauritius was sitting on top of a sunken continent that is billions of years old.
The study was published in Nature Communications.
According to Ashwal, the pieces of Mauritia formed after the splintering of Gondwana supercontinent is still spread over the Indian Ocean.
The sunken continent was formed when India broke away from Africa billions of years ago. Gondwana disintegrated 200 millions of years ago with splinters later becoming Africa, Australia, South America, and Antarctica.
Broader Study Required
According to the research, the presence of a continental crust has been indicated by the old Mauritian zircons showing the ancient crust's affinity with Madagascar, which is 700 km west of Mauritius now. It said a broad reconstruction that traces linkages of Mauritius and the continental fragments as an erstwhile part of the ancient nucleus of Madagascar and southern India needs to be attempted.
"We are studying the break-up process of the continents, in order to understand the geological history of the planet," said Ashwal, also the study's lead author.
Analysis of volcanic rocks in Mauritius led the scientists to establish the Mauritius connection firmly. Finding plenty of zircons at the beaches, which were extremely old and spewed by volcanic eruptions, the team was led to clear conclusions. There was a huge age disparity between the young Mauritius that was just 8 million years old and zircon crystals aged at least 3 billion years.
"The fact that we have found zircons of this age proves that there are much older crustal materials under Mauritius that could only have originated from a continent," said Ashwal.
Finding such old minerals in the relatively young Mauritius led to the surmise that the island was sitting on top of a sunken continent.
Huge Gravity Pull
The discovery came in the aftermath of the high gravitational fields exerted in some parts of the ocean thanks to the extremely thicker crusts.
Beneath the sea, huge chunks of land that sank got attached to the ocean's crust.
Experts conclude that Mauritia must have been a small continent. When India and Madagascar started drifting apart, Mauritia felt the stress and stretched far and eventually broke up.
The assumption is that Mauritia sank into the sea 84 million years ago.
"It's like plasticine: when continents are stretched they become thinner and split apart," noted Martin Van Kranendonk at the University of New South Wales in Australia.