Researchers confirm 'lost continent' below Mauritius

A layover on a trip to India began a research odyssey that has led scientists to verifythe existence of a "lost continent" below the East African island nation of Mauritius in the Indian Ocean.

A paper published in the journal Nature Communications this week outlined the presence of ancient continental crust broken off from a larger "super-continent" under the volcanic island best known for its beach resorts.

Lead authorLewis Ashwal, a geologist at theUniversity of the Witwatersrand in Johannesburg, South Africa, wasn't looking for a day at the beach when he and some colleagues had a one-night layover in Mauritius en route to India.

"We're not the kind of people who are going to waste a day reading a book and getting a sunburn," says Ashwal, who is part of a group of scientists who studythe age of rocks in places like India, Madagascar and the Seychelles, with the aim oflearning more about how the continents broke apart.

"Swimming who cares?I've doneenough of that."

So he and his colleagues rented a car and headed inland from the tiny nation's gorgeous coral beaches, through sugar plantations andto volcanic craters, where they collected rocks containing the mineral zircon.

Zircon is found mainly in the granites that form continents.

Although it would take years and many more trips to Mauritiusto prove, the group has now shownthat the rocks underthe island date back as far as threebillion years.

The breakup of a super-continent

That'sancient compared to the oldest volcanic rocks that make up the island, which are just nine million years old at most.

The lost continentis part of a super-continent known to scientists as Gondwana, which broke apart into Africa, India, Australia and Antarctica when the Indian Ocean was formed.

The researchers arecalling the newly foundcontinentMauritia.

On that first foray away from Mauritius'sgated resorts, a colleague from Norway found rocks containing zircon crystals. But problems with sample contamination caused by the crushing equipment in his Oslo labrendered the results useless.

"He was very depressed and he sort of dropped [the research]," says Ashwal.

Sampling with sand toys

But four years later another group returned to Mauritiusto get samples of zircon that didn't need to be crushed those found in beach sand.

The scientistsused ordinary beach toys meant for building sandcastles. "Clean stuff, because if you bring tools from the lab, they could be contaminated," Ashwal says.

He and colleagues published their findings about thosebeachfront zircon samples in 2013.

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But other scientists were skeptical, he says.

Critics postulated that the beach zircon could have been transported to Mauritiusby wind, waves, vehicle tires, people's shoes even bird poop.

"It began to get ridiculous," says Ashwal.

But the group pressed on another two years, sampling and analyzinga wide variety of rocks and getting isotope data showing "spectacular ages," he says.

At 2.5 tothreebillion years old, these samples brought to the surface through volcanic eruptions show what has to be a continent, says Ashwal. "There's no other place that rocks these old are found."

How the world works

Finding a "new-to-us" continent is about much more than this discovery alone.

"Our work is addressing the question of howcontinents break apart from each other and hownew oceans are formed," says Ashwal.

"If we are able to reconstruct their positions in the past, where they were and at what time in thepast, then we can understand better how the earth works."

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