[meteorite-list] Giant Meteor Hit Ozarks Long Ago, Researcher Says

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:10:06 2004
Message-ID: <200304101615.JAA28649_at_zagami.jpl.nasa.gov>

http://www.stltoday.com/stltoday/news/stories.nsf/News/9046EC7E9E70FF1786256D04000FDD65

Giant meteor hit Ozarks long ago, researcher says
By Jake Wagman
St. Louis Post-Dispatch
April 9, 2003

With the help of some fancy photo tricks and good old-fashioned digging, a
Southwest Missouri State University research team has confirmed that a giant
meteor hit the Ozarks millions of years ago.

"It's a big chunk of rock," said SMSU geologist Kevin Evans. "It would be
twice as tall as the Arch."

Evans estimates that the meteor, which probably hit Earth 340 million years
ago, was at least 1,300 feet wide. Because it was racing toward the planet
at up to 100,000 miles an hour, it created a depression 47 times its size
when it hit.

The impact area, at 12 miles across, is the fifth-largest known meteor
landing site in the country and one of the top 50 in the world, said Evans,
who presented the group's findings at a meeting last month of the Geological
Society of America.

Scientists have long speculated that a meteor hit the area near Osceola, Mo.

Evans' discovery came after he downloaded digital images of the area
provided by the U.S. Geological Survey. He viewed several topographic maps
of the area, looking for a circular ridge that would hint at a meteor
impact. Unsuccessful, he turned to Photoshop, a computer program popular
with professional photographers, and merged four of the pictures.

He could then see the "forest for the trees" - the impact ring was at the
edge of the images he had been looking at, and was a lot larger than he had
expected.

"My mouth dropped," said Evans. "The exact center of this thing is almost at
the corner of four maps."

The "smoking gun" was discovered later, Evans said, when geologists found
"shocked" quartz crystals at the site, a condition that can only be caused
by an enormous collision, like a meteor.

Evans and his team are exploring whether the site could help prove that a
series of meteors could have hit Earth at the same time along the same
latitude line.

There are two other meteor impacts in Missouri, but they are much smaller
than the Ozark site, now being called the Weaubleau-Osceola impact.

Reporter Jake Wagman:
E-mail: jwagman_at_post-dispatch.com
Phone: 314-340-8172
Received on Thu 10 Apr 2003 12:15:38 PM PDT