A team of geologists from the University of Oslo in Norway recently found evidence of a lost subcontinent under the Indian Ocean. The submerged landmass allegedly sunk during the break-up of the prehistoric supercontinent Rodinia, which once joined India and Madagascar 85 million years ago (1).
Geologist Bjørn Jamtveit and his Norwegian team based their findings on sand samples collected from two remote sites along the beaches of Mauritius, a volcanic island located roughly 900 miles east of Madagascar (2).
According to Jamtiveit, Mauritius itself is a relatively young island— its oldest lava basalts date back to just 8.9 million years ago (1). Yet the researchers, using radiometric dating, identified nearly 20 zirconium silicate crystals within the collected samples that were between 660 million and 1.97 billion years old – ages more consistent with those of continental rocks (2).
These crystals, called zircons, are highly resistant to corrosion and chemical reactions (1). Their presence on such a young and remote island suggests the existence of buried continental material underneath the sea floor. Jamtveit and his team theorized that the same plate tectonic activity that sent the Indian subcontinent shooting off to the northeast during the breakup of Rodinia also tore off a landmass three times the size of Crete (1). Subsequent thinning and spreading of the ocean crust dragged the landmass underwater until volcanic eruptions brought submerged continental rock fragments back to the surface (1).
Additional studies back up the Norwegian team’s findings. Analysis of the Earth’s gravitational field reveals large areas of the sea floor near Mauritius where the Earth crust is much thicker than normal— up to 30 kilometers thick compared to the usual 5-10 kilometers (1). These sea floor anomalies may well be the remnants of the lost continent.
Furthermore, it is unlikely that the zircon particles were transported to the island from another continental landmass via wind or human means because of the crystals’ large size and the remote locations from which the samples had been taken respectively (1).
While more research is still needed to fully confirm the presence of the submerged continent, Jamtveit and his team’s findings could unearth the existence of numerous sunken landmasses peppered across the ocean floors (2).
- K. Than, Ancient Lost Continent Discovered in Indian Ocean. (2013) Available at http://news.nationalgeographic.com/news/2013/02/130225-microcontinent-earth-mauritius-geology-science/
- S. Perkins, Long-lost Continent Found Under the Indian Ocean. (2013) Available at http://www.nature.com/news/long-lost-continent-found-under-the-indian-ocean-1.12487