A view of the Morrow County meteorite, showing the sculpted surface texture caused by passage through the Earth's atmosphere. The meteorite has a distinctive yellowish color caused by mild weathering on Earth. A portion of the meteorite at bottom right has been removed for study. At the top, another portion is missing, which was removed before Donald Wesson found the rock, possibly by a farm plow. Full Story.
Credit: Portland State University
This article was updated at 3:45 p.m. ET.
A seemingly normal rock found in a ditch along a stretch of road in north central Oregon has turned out to be a stone from outer space that travelled across millions of miles and billions of years to reach Earth, according to researchers studying the stone.
The 40-pound, cone-shaped space rock, which is about the size of a beach ball, was picked up by Donald Wesson and his wife Debbie during the fall of 1999 as they drove through Oregon's wheat country on their way home to Washington. It is the fifth meteorite to be found in the northwestern state.
The space rock, which sat anonymously on the planet's surface for a few hundred to a thousand years, remained unidentified for another decade as it rested in Wesson's garden.
Only after spending time beneath a deck barbeque, visiting a county fair and passing through two universities did it receive the official classification as a meteorite. [Meteorite craters on Earth.]
"It was probably plowed up by a farmer and tossed to the side of the road," said Dick Pugh, a geologist at Portland State University in Oregon. "There is even evidence that the rock was hit by a plow."
Space rock's tall tale
Wesson finally began asking around after watching a television program about meteorites. He took the rock to a local county fair in Castle Rock, Washington in the summer of 2009, where he spoke with a member of the Southern Washington Mineralogical Society.
The find was referred to Western Washington University in Bellingham, Wash., where initial sample tests showed it was probably a meteorite. Final confirmation came from the Cascadia Meteorite Laboratory at Portland State University, which classified the Morrow County meteorite as an L6 ordinary chondrite that had been highly shocked (S5) but minimally weathered (W1).
The latest find represents a relatively common type of meteorite, according to Melinda Hutson, a planetary scientist at Portland State University who helped make the classification. But, she added that it has several intriguing features.
"The meteorite isn't significantly weathered, but it has a distinctive yellow tint caused by weathering unlike that seen in meteorites recovered from deserts in Africa or Antarctica," Hutson said. "Also, it has beautiful shock veins and glass, caused by a major collision in space."
Based on its type, the Morrow County meteorite was likely formed approximately 4.5 billion years ago, said Alex Ruzicka, a planetary scientist at Portland State University.
"Given the kind of meteorite that it is, and the shock effects that it experienced, it probably started its travels to Earth from the asteroid belt about half a billion years ago," Ruzicka told SPACE.com.
Morrow County meteorite
Both the name and classification of the meteorite have received official approval from the Nomenclature Committee of the Meteoritical Society, and a type sample now resides with Portland State University.
Meteorites can easily remain anonymous in Oregon's heavily forested lands west of the Cascades, and many dark-colored volcanic rocks to the east of the Cascades look similar to real, dark-colored meteorites.
Dark bedrock geology and high levels of precipitation translate into 34 times fewer meteorites recovered in Oregon per square mile than in Kansas, a state with light-colored bedrock and very little forest. But that has not dimmed the confidence of Oregon's meteorite hunters.
Previously, only four meteorites have been recovered from Oregon, including Sam's Valley, found in 1894; Willamette, found in 1902; Klamath Falls, found in 1952; and Salem, which fell in 1981. Three of these are iron meteorites, whereas Salem and the newly classified Morrow County are both stony meteorites.
The Morrow County meteorite is substantially bigger than the Salem fragment, which is only a few centimeters across, said Ruzicka. The Salem meteorite was found by a policeman, after it hit the roof of his car in the late evening while he was off duty.
"In a way, I'm not surprised at all by this discovery," Ruzicka said. "With our vigorous outreach effort I always knew the lab would help to recover more meteorites from Oregon, I just didn't know when. Maybe this will be the start of many more to come"
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