Lost continent themes including Atlantis, Mu and Lemuria have always fascinated scientists and fiction writers.
But scientists led by Trond Torsvik from the University of Oslo say they have identified a micro-continent that sunk beneath the western Indian Ocean, near Mauritius, millions of years ago.
Professor Torsvik says he believes one part of the continent survived and now forms the Seychelles - an isolated group of islands between Madagascar and India.
"At the moment the Seychelles is a piece of granite or continental crust which is sitting practically in the middle of the Indian Ocean, but once upon a time it was sitting north of Madagascar," he said.
"What we're saying is that maybe this was much bigger and there are many of these continental fragments which are spread around in the Indian Ocean."
Thousands of millions of years ago, all of Earth's landmasses were united in one massive continent, with India sitting next to Madagascar.
Professor Torsvik says the continent probably submerged when India separated from Madagascar as the continental plates moved.
The researchers were surprised to find ancient zircon minerals hundreds of millions of years older than expected at the site.
Richard Arculus, a professor of geology at the Australian National University, has been reviewing the study published this week in the journal Nature Geoscience.
He says the zircon fragments were brought to the surface by volcanic activity from a piece of continental crust buried beneath the ocean.
"Mauritius itself is located over on a bank which stretches from Mauritius itself, through what's called the Mascarene Plateau, up towards the Seychelles," he said.
"We've known for a while that that's likely to be a micro-continent left behind as India has ruptured away from Madagascar."
Professor Torsvik says the location of the submerged fragments could hold important benefits to the communities living above them.
"Under the law of the sea, if you can demonstrate you have a piece of continental crust on which you can put your flag, you can immediately claim 200 nautical miles around it. And that's yours under the law of the sea to do what you like with economically," he said.
"So there's some degree of economic significance to something that might be purely scientific in terms of its discovery."