[meteorite-list] Sutter's Mill Meteorite Preserved For Present and Future Scientists

[Ron Baalke]

http://carsonnow.org/story/08/21/2013/rare-meteorite-preserved-present-and-future-scientists
 
Rare meteorite preserved for present and future scientists
by Jeff Munson
Carson Now
August 21, 2013

The main mass of a rare meteorite observed in the skies over Carson City, 
Carson Valley and Lake Tahoe that exploded over California's Sierra foothills 
in April 2012 will be preserved for current and future scientific discoveries, 
thanks to the collaborative efforts of five U.S. academic institutions.

It has found a permanent home divided among the University of California, 
Davis; the Smithsonian Institution's National Museum of Natural History 
in Washington, D.C.; American Museum of Natural History in New York City; 
The Field Museum of Natural History in Chicago; and Arizona State University 
in Tempe. Together, the institutions have successfully acquired the biggest 
known portion of the Sutter's Mill meteorite.

The meteorite is considered to be one of the rarest types to hit the Earth 
-- a carbonaceous chondrite containing cosmic dust and presolar materials 
that helped form the planets of the solar system.

Its acquisition signifies enhanced research opportunities for each institution 
and ensures that future scientists can study the meteorite for years to 
come.

"With these museums and institutions storing the meteorite's main mass, 
it leaves it in a pristine condition to preserve for future generations 
to study," said UC Davis geology professor Qing-zhu Yin. "Fifty or 100 
years from now, we may have new technology that will enable later generations 
to revisit the meteorite and do research we haven't thought of. This gives 
us a better chance to realize the full scientific value of the meteorite, 
rather than have it be just a collector's item."

The meteorite formed about 4.5 billion years ago. While it fell to Earth 
roughly the size of a minivan before exploding as a fireball, less than 
950 grams have been found. Its main mass weighs just 205 grams (less than 
half a pound) and is about the size of a human palm.

The main mass was X-rayed by CT scan at the UC Davis Center for Molecular 
and Genomic Imaging. This was the first time a meteorite acquisition was 
CT scanned before its division among a consortium of institutes, allowing 
prior knowledge of each piece's contents. Then it was cut into five portions, 
reflective of each institution's investment, before being delivered to 
the institutions.

The portion of the main mass acquired by each institution includes:

* American Museum of Natural History: 34 percent
* Smithsonian Institution's National Museum of Natural History: 32 percent
* The Field Museum of Natural History: 16 percent
* Arizona State University: 13 percent
* UC Davis: 5 percent

When the meteorite landed near Sutter's Mill, the gold discovery site 
that sparked the California Gold Rush, it spurred a scientific gold rush 
of sorts, with researchers, collectors and interested citizens scouring 
the landscape for fragments of meteorite. The institutions that have acquired 
the main mass were among those that acted on this rare scientific opportunity 
to gain insights about the origins of life and the formation of the planets.

At UC Davis, for instance, the meteorite fell just 60 miles east of the 
main campus. Yin immediately traveled to the site with students and colleagues, 
looking for specimens and reaching out to the public to provide meteorite 
donations for science. He confirmed for the original discoverer of the 
main mass that it was carbonaceous chondrite. Yin and his UC Davis colleagues 
have also X-rayed the meteorite and determined its age and chemical composition.

"It just happened in our backyard,' said Yin. "I felt obligated to do 
something, and I still do."

Involvement from the other institutions included:

* The American Museum of Natural History worked closely with Yin to secure 
specimens of the Sutter's Mill meteorite right after its fall, and performed 
nondestructive computed tomography (CT) scans of several specimens kindly 
loaned by their finders. These scans were used to determine the density 
of several samples to very high accuracy, confirming the type of meteorite 
represented by Sutter's Mill.

* The Field Museum of Natural History found several presolar stardust 
grains in two smaller pieces of the meteorite donated by private collector 
Terry Boudreaux. Presolar stardust grains are the oldest solid samples 
available to any lab and are essentially time capsules from before the 
solar system formed 4.6 billion years ago.

* Arizona State University's Meenakshi Wadhwa, director of the Center 
for Meteorite Studies, was contacted by Robert Haag, the private collector 
who owned the main mass. She then contacted the other institutions to 
initiate its joint acquisition.

* The Smithsonian Institution cut the mass into five portions.

Last spring, UC Davis alumnus Gregory Jorgensen and donor Sandy VanderPol 
provided nearly 3 grams of the Sutter's Mill meteorite to Yin's lab at 
UC Davis. Those 3 grams allowed UC Davis to learn the meteorite's age 
and chemical composition. The university's recent acquisition of another 
10 grams of the main mass will allow for even further research, including 
searching for presolar grains and performing isotopic analysis.

UC Davis' section of the meteorite was funded by a portion of Yin's Chancellor's 
Fellowship.