3 billion-year-old "lost continent" lurking under African island [View all]
By TIA GHOSE LIVESCIENCE.COM February 1, 2017, 11:09 AM
It’s official: A 3-billion-year-old “lost continent” lurks beneath the Indian Ocean island of Mauritius, new research confirms.
Sparkly, iridescent flecks of rocks known as zircons from Mauritius date back billions of years, to one of the earliest periods in Earth’s history, the researchers found. Other rocks on the island, by contrast, are no more than 9 million years old.
“The fact that we have found zircons of this age proves that there are much older crustal materials under Mauritius that could only have originated from a continent,” Lewis Ashwal, lead author of the new study and a geologist at the University of the Witwatersrand, Johannesburg in South Africa, said in a statement.
Earth’s crust is made up of two parts: the planet’s continents, which rise high above the oceans because they are composed of lighter rocks such as granite; and the ocean basins, which sink lower because they are made up of denser rocks such as basalt, according to a video about the new study. Whereas the continental crust may be 4 billion years old, oceanic crust is much younger, and is continually being formed as molten rock spews through fissures in the ocean floor, called midocean ridges.
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http://www.cbsnews.com/news/3-billion-year-old-lost-continent-lurking-under-african-island/
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