Astronomy

45 Billion Year old Meteorite Yields new Mineral



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A 4.5 billion year old meteorite that was found in Northwest Africa was found to hold the first extraterrestrial example of a mineral called krotite. The excitement about krotite is that is is among the earliest minerals and is believed to be one of the building blocks of planets.

The meteorite is called NWA 1934 CV3 carbonaceous chondrite. While krotite has never been found naturally on the Earth's surface, carbonaceous chondrite meteorites are only about 5% of extraterrestrial rocks. It is interesting that man made krotite is synthesized through a high heat process and is used in some concretes.

How does this mineral form? According to the Tehran Times, It is a mix of calcium, aluminum and oxygen that is subjected to temperatures as high as  2,732 degrees Fahrenheit or  1,500 degrees Celsius.

The newly discovered krotite was the dominant mineral in the center and mantle of the 1934 CV3 meteorite. It is described as a 2.75 millimeter by  4.5 millimeter inclusion that is made up mostly of  krotite crystals along with a few other calcium-aluminum or magnesium-aluminum oxides and a few silicates. The construct is described as a thin rim of concentric layers.

One explanation is that the mineral formed in this CAI, then was introduced into a hot gas. The hot gas did not melt the CAI but might have reacted with the krotite crystals that were on the surface, forming a layered rim.

Of course, when it impacted the earth the meteor went through much heat and some impact, but not enough to "shock" or change the structure of the crystals inside. This was followed by any weathering and natural effects that came in the Northwest African physical environment.

Krotite is named after Alexander N. Krot, a well recognized metoritics researcher at the University of Hawai‘i at Mnoa. He has worked extensively to understand how calcium-aluminum-rich inclusions and chondrules are formed, and according to the UH News, he has made significant contributions to understanding the processes iof the early solar system.

Current wisdom is that calcium and aluminum rich inclusions were the first solids to form 4.6 billion years ago, when there was just a solar nebula. Cosmochemist study these solids in order to painstakingly stitch together the records of how these building blocks became asteroids and, on a larger scale, planetoids and planets.

It is believed that the krotite meteorite came from the asteroid belt and is a part of one asteroid. When meteors form, they are either pieces of asteroids, which are simply space rocks. But the rarest of the meteorites are formed as debris that flew into space after impacts on the moon and Mars. 

When a meteor hits the Earth's surface, it is called a meteorite. Chondrites are very primitive meteorites.


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ARTICLE SOURCES AND CITATIONS
  • InfoBoxCallToAction ActionArrowhttp://www.hawaii.edu/newsatuh/2011/05/krotite/
  • InfoBoxCallToAction ActionArrowhttp://www.tehrantimes.com/index_View.asp?code=240308
  • InfoBoxCallToAction ActionArrowhttp://www.hawaii.edu/news/article.php?aId=4415