Diamond-Bearing Pebble Provides Evidence of Comet Striking Earth

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Libyan Desert Glass: Diamond-Bearing Pebble Provides Evidence of Comet Striking Earth

 

A mysterious black pebble found by an Egyptian geologist at the Libyan Desert Glass strewnfield provides the first ever evidence of a comet entering Earth?s atmosphere and exploding.

 

This is an artist?s impression of the comet exploding above Egypt. Image credit: Terry Bakker.

 

The comet entered the atmosphere above Egypt about 28.5 million years ago. It exploded, heating up the sand beneath it to a temperature of about 2,000 degrees Celsius, and resulting in the formation of a huge amount of yellow silica glass, called the Libyan Desert Glass.

A magnificent specimen of the Libyan Desert Glass, polished by ancient jewelers, is found in Tutankhamun?s brooch with its striking yellow-brown scarab.

Prof Jan Kramers from the University of Johannesburg, a lead author of the paper published online in the journal Earth and Planetary Science Letters, and his co-authors analyzed the diamond-bearing pebble ?Hypatia,? named in honor of the first well known female mathematician, astronomer and philosopher, Hypatia of Alexandria.

After conducting highly sophisticated chemical analyses on this pebble, the team came to the inescapable conclusion that it represented the very first known specimen of a comet nucleus, rather than simply an unusual type of meteorite.

?It?s a typical scientific euphoria when you eliminate all other options and come to the realization of what it must be,? Prof Kramers said.

?The impact of the explosion also produced microscopic diamonds. Diamonds are produced from carbon bearing material. Normally they form deep in the earth, where the pressure is high, but you can also generate very high pressure with shock. Part of the comet impacted and the shock of the impact produced the diamonds.?

 

 

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