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Libyan Desert Glass
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First ever evidence of a comet striking Earth

The first ever evidence of a comet entering Earths atmosphere and exploding, raining down a shock wave of fire which obliterated every life form in its path, has been discovered by a team of South African scientists and international collaborators, and will be presented at a public lecture on Thursday.
The research, which will be published in Earth and Planetary Science Letters, was conducted by a collaboration of geoscientists, physicists and astronomers including Block, lead author Professor Jan Kramers of the University of Johannesburg, Dr Marco Andreoli of the South African Nuclear Energy Corporation, and Chris Harris of the University of Cape Town.
At the centre of the attention of this team was a mysterious black pebble found years earlier by an Egyptian geologist in the area of the silica glass. After conducting highly sophisticated chemical analyses on this pebble, the authors came to the inescapable conclusion that it represented the very first known hand specimen of a comet nucleus, rather than simply an unusual type of meteorite.

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RE: Kebira Crater
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Libyan Desert Glass
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Tutankhamun's Fireball

Today on Discovery Enterprise we join a team of interdisciplinary scientists in a solving a scientific detective story worthy of Sherlock Holmes. Our mystery begins in Cairo's Museum of Egyptian Antiquities when an Italian mineralogist discovers a mysterious green gem in the center of Tutankhamun's necklace. A gem compose of a bizarre form of glass whose origins can only be traced to a time well before the dawn of Egyptian civilization and the fiery heat of a nuclear conflagration. The game is afoot when we go on an intrepid odyssey into the heart of the blistering Sahara desert in search of Tutankhamun's Fireball.
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Ed ~ it should be noted that the Kebira Crater is not the source of the Libyan desert glass. These were two different events.

-- Edited by Blobrana on Friday 26th of February 2010 04:05:58 PM

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In December 1932, Patrick Clayton, a surveyor from the Egyptian Geological Survey, drove between the dunes of the Great Sand Sea, close to the Saad Plateau in Egypt, when he heard crunching under the wheels. When he examined what was causing the sound, he found great chunks of glass in the sand.
The find caught the attention of geologists around the world and planted the seed for one of the biggest modern scientific enigmas. What phenomenon could be capable of raising the temperature of desert sand to at least 3,300 degrees Fahrenheit, casting it into great sheets of solid yellow-green glass?

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Ed
~ We now know that the desert glass was formed by a meteoritic airburst.

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 Libyan Desert Glass : Libyan Desert Glass is the remaining evidence of a tremendous asteroid or comet impact with Earth. Probably an air burst explosion caused the released sufficient heat to melt and fuse to glass the surface of the ground.



Libyan Desert Glass (sometimes referred to as Egypt or Egyptian Desert Glass) is a rare and beautiful impact glass, found in only one remote location on Earth, near the Libyan/Egyptian border

Impactglass, : 99 % SiO2, Inclusions of  Cristobalite & Lechatelierite
Age : 28.5 Million Years
Hardness : 6,
Spec. Weight : 2.206 - 2.202


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-- Edited by Blobrana at 19:02, 2008-04-20

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75 years ago today, an expedition led by Patrick Clayton, members of the Egyptian Desert Survey, discovered a large concentration of  glass nodules strewn across the dunes of western Egypt, near the Libyan border.
However, the yellow and green glass  had been  discovered  long before that -- a scarab made from sliver and the  glass  was found  in the tomb of King Tutankhamun.
And remarkable, the origin of the glass may come  from a  31 kilometre  wide impact crater, that occurred  29 million years ago.

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Simulations show that the material of an incoming asteroid is compressed by the increasing resistance of Earths atmosphere. As it penetrates deeper, the more and more resistant atmospheric wall causes it to explode as an airburst that precipitates the downward flow of heated gas.
Because of the additional energy transported toward the surface by the fireball, what scientists had thought to be an explosion between 10 and 20 megatons was more likely only three to five megatons

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