​Long Lost Continent Found In Indian Ocean Under Basin

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February 26, 2013
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The mystery of the long lost continent has been found in the Indian Ocean after geologist at the University of Oslo found fragments of a volcanic rock that is scattered beneath the waters.

In fact, there has been evidence from Mauritius, a volcanic island about 559 miles east of Madagascar. The oldest basalts on the island date to about 8.9 million years ago, says Bjorn Jamtveit, a geologist at the University of Oslo.

Yet grain-by-grain analyses of beach sand that Jamtveit and his colleagues collected at two sites on the Mauritian coast revealed around 20 zircons — tiny crystals of zirconium silicate that are exceedingly resistant to erosion or chemical change — that were far older.

The zircons had crystallized within granites or other igneous rocks at least 660 million years ago, says Jamtveit. One of these zircons was at least 1.97 billion years old.

Jamtveit and his colleagues suggest that rocks containing the wayfaring zircons originated in ancient fragments of continental crust located beneath Mauritius. They propose that geologically recent volcanic eruptions brought shards of the crust to Earth’s surface, where the zircons eroded from their parent rocks to pepper the island’s sands.

The team chose to collect sand, rather than pulverize local rocks, to ensure that zircons inadvertently trapped in rock-crushing equipment from previous studies did not contaminate their fresh samples.

The nearest known outcrop of continental crust that could have produced the Mauritian zircons is on Madagascar, far across a deep sea, Jamtveit notes.

Furthermore, the zircons came from Mauritian sites so remote that it is unlikely that humans carried them there.

“There’s no obvious local source for these zircons,” says Conall Mac Niocaill, a geologist at the University of Oxford, UK, who was not involved in the research.

Also, it does not seem as if the zircons rode to Mauritius on the wind, says Robert Duncan, a marine geologist at Oregon State University in Corvallis. “There’s a remote possibility that they were wind blown, but they’re probably too large to have done so,” he adds.

These type of ocean basins are known as “ghost continents” and there’s several more to explore.

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