Though the lost city of Atlantis may well be a myth, scientists in the southern hemisphere have discovered evidence of a real-life lost continent underneath the volcanic island of Mauritius. The first clues to the existence of the prehistoric landmass surfaced in 2013, when the scientist Lewis Ashwal and his colleagues at the University of the Witwatersrand in South Africa discovered that Mauritius exerted a stronger gravitational pull than other areas of the Indian Ocean.
One possible explanation for this, the scientists theorized, was that the island was sitting on top of pieces of a sunken continent. Though Mauritius is about 8 million years old, they found zircon crystals from the island’s beaches that were nearly 2 billion years old, suggesting that volcanic eruptions could have ejected these pieces of ancient rock from the sunken continent below.
In a new study, published this week in the journal Nature Communications, Ashwal and his team report finding some of the tiny zircon crystals that are even older—up to 3 billion years old, in fact. While some scientists raised concerns that the previously found crystals may have been transported to the island as part of construction material or ship’s ballast, the researchers in the new study extracted the new crystals directly from rocky outcrops on the island, eliminating any such doubts. By analyzing these zircon crystals, and comparing their ages with those of nearby landmasses, the researchers have been able to reconstruct the geological history of the lost continent, which they dubbed Mauritia.
That history begins with Pangaea, the gigantic landmass that incorporated nearly all of the Earth’s continental crust, which is believed to have existed during the late Paleozoic and Mesozoic eras. (German meteorologist Alfred Wegener first proposed Pangaea’s existence in 1912, as part of his theory of continental drift.) According to the new study, Mauritia once formed part of Gondwana, one of two supercontinents that Pangea split into between 200-300 million years ago. Gondwana itself later broke apart, into what are now the continents of Africa, South America, Antarctica and Australia, as well as the Arabian Peninsula, India and Madagascar.
After Gondwana split apart, the researchers believe, the now-lost continent of Mauritia ended up sandwiched between India and Madagascar, which were then much closer to each other than they are today. Mauritia was a small continent, about a quarter the size of Madagascar. Around 85 million years ago, after India and Madagascar started to pull further apart from each other, Mauritia began to stretch as well. Volcanic eruptions, or shifting tectonic plates, split the continent apart, and layers of molten lava buried the fragments. Some of the land, including the zircon crystals found by the scientists, appears to have been recycled into the magma that later formed the island of Mauritius.
“It’s like plasticine: when continents are stretched they become thinner and split apart,” explained Martin Van Kranendonk, of the University of New South Wales in Australia, to New Scientist. “It’s these thin pieces that sink below the ocean.” In addition to Mauritius, the researchers think pieces of Mauritia may also lie below other volcanic islands in the Indian Ocean, such as Cargados Carajos, Laccadive and the Chagos islands.