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Scientists from Australia solve mystery of yellow glass in the Libyan desert




Alwasat - Cairo 6 days
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Scientists from Australia have solved the mystery of the strange yellow glass in the Libyan desert saying it was caused by the direct impact of a space meteorite into the Earth.

Geologist and planetary scientist Aaron Cavosie of Curtin University in Australia has finally uncovered the mystery of this strange yellow glass nearly 30 million years after it was formed on Earth, according to the French site «Fredzone» on Saturday.

He explained that "Libyan glass is a kind of natural glass spread over an area of ​​6,500 square kilometers of the Libyan desert, and includes even western Egypt, where they used it as decoration because of the strange yellow color during the reign of Tutankhamun, but yellow glass in the desert has existed for much longer."

The new “smoking gun” for understanding the origin of the Libyan desert glass is evidence of an unusual mineral called reidite. Reidite only forms during a meteorite impact, when atoms in the mineral zircon are forced into a tighter arrangement.

Such high-pressure minerals are a hallmark of a meteorite impact.

Zircon is a common mineral in granite, sandstone and other rock types. It is known from Earth, the Moon, Mars, and various meteorites. It is widely used for dating when rocks formed.

Zircon is also useful when searching for evidence of shock deformation caused by a meteorite impact. At low shock intensity, zircon deforms by bending of the crystal. It is like bending a plastic spoon to the point where it deforms but does not break.

As the shock intensity increases, zircon further responds in several unique ways and at extreme pressures, reidite forms.

If the rocks then get hot, zircon will recrystallise. This results in the formation of a network of new, tiny interlocking grains. Above 1,700℃ zircon ultimately breaks down to zirconia.

Libyan desert glass contains many zircon grains, all smaller than the width of a human hair.

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