[meteorite-list] Student Research Cracks Origin Story of Meteorite

[Ron Baalke]

http://news.fsu.edu/More-FSU-News/FSU-student-researcher-cracks-origin-story-of-meteorite

FSU Student Research Cracks Origin Story of Meteorite
Kathleen Haughney
February 25, 2016

A Florida State University student has cracked the code to reveal the 
deep and interesting history of an ancient meteorite that likely formed 
at the time our planets were just developing.

Jonathan Oulton, a 2015 FSU graduate, working with Earth, Ocean & Atmospheric 
Science Professor Munir Humayun, studied the pieces of a meteorite called 
Gujba. Using sophisticated lasers and mass spectrometers at the FSU-headquartered 
National High Magnetic Field Laboratory, Humayun and Oulton conducted 
in-depth chemical analysis of the meteorite samples that shattered previous 
theories about when and how this meteorite had formed.

"We tried to elucidate a story about its origins through this science," 
said Oulton, who is now pursuing a doctoral degree at University of Colorado.

Previously, scientists believed that Gujba was formed more or less from 
the dust of the solar system.

But, as Humayun and Oulton analyzed it, they discovered it had a far more 
complex geological history than previously thought. They inferred that 
Gujba formed from the debris of a collision between a parent planet that 
had both a crust and mantle, something that would only be found on a fairly 
large planet of the kind that is not seen today in the asteroid belt.

[Photo]
A piece of  the meteorite Gujba.

To get that type of formation, Gujba would have been involved in more 
than the equivalent of a solar system fender bender.

Oulton, Humayun and their collaborators argue that Gujba formed from the 
molten debris produced when a large metallic body smashed into another 
planet and both bodies were destroyed in the process. Based on chemical 
traces preserved in Gujba, the target planet might have been even larger 
than the asteroid 4 Vesta, one of the largest bodies in the asteroid belt 
with a diameter of about 326 miles or 525 kilometers.

"People used to say that meteorites like Gujba were the building blocks 
of the solar system," Humayun said. "Now, we know it's the construction 
debris of the planets, to borrow a phrase from Ed Scott of the University 
of Hawaii."

The research will be published in an upcoming issue of Geochimica et Cosmochimica 
Acta, but is currently available online.

Oulton presented the preliminary results of the paper at the 2015 Lunar 
& Planetary Science Conference and received the Dwornik Award of the Geological 
Society of America for the best undergraduate presentation.

"In a broad sense, people have been trying forever to understand how we 
got here," Oulton said. "Although this doesn't get to that directly, this 
research gives us a greater understanding of the physical chemistry of 
everything that occurred at the time the Earth formed."

Oulton served as the lead author on the article. Other researchers on 
the paper are Lawrence Grossman and Alexei Fedkin of The University of 
Chicago.