[meteorite-list] New Report on Odessa Crater Raises Question: Are We Due?

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Jan 24 18:33:15 2006
Message-ID: <200601242308.k0ON8NR02217_at_zagami.jpl.nasa.gov>

http://www.columbusdispatch.com/science/science.php?story=dispatch/2006/01/24/20060124-B9-02.html

New report on Odessa crater raises question: Are we due?
DALE GNIDOVEC
Columbus Dispatch (Ohio)
January 24, 2006

The specimen isn't much to look at - it's heavy and rusty, and about the
size of my fist. A casual observer might mistake it for a chunk of old
farm machinery, but in fact it's a meteorite.

Rather, it is a small piece of one formed about the same time as Earth,
4.6 billion years ago. It died in a spectacular collision with our
planet just yesterday in geologic terms, a mere 63,500 years ago.

Our chunk is a piece of the Odessa meteorite, named for the town in
western Texas not far from the southeastern corner of New Mexico. Five
craters are clustered there, four small ones and a larger one. The
largest is about 525 feet across and nearly 100 feet deep.

Discovered in 1921, it was only the second meteorite crater identified
in the United States. Thousands of fragments of the meteorite have been
found, including some in 1935 using one of the world's first metal
detectors. The largest recovered so far weighs 300 pounds, and the
fragments have a combined weight of more than 10 tons.

They are composed of about 90 percent iron, 8 percent nickel and a
smattering of other elements. A lot of research has been done on those
pieces, but some recently published research investigated the craters
and the surrounding area to get an idea of what the impact was like.

It would have been a spectacular event for anyone - or anything - around
to see it. Animals living in the area at that time, which was open,
semiarid grassland much as it is today, included mammoths, horses, bison
and camels.

Hitting the atmosphere at 25,000 to 38,000 mph, the meteorite
fragmented. The impact produced winds of more than 600 mph and severely
damaged everything within 2 miles. Any animals within that zone were
probably killed instantly. The energy released was equivalent to a
magnitude 3.1 earthquake.

Some researchers have proposed that the Odessa meteorite and the one
that made the more famous Barringer Crater (also known as Meteor Crater)
near Winslow, Ariz., were part of the same fall. Both are quite recent
impacts, as these things go, and both were made by the same kind of
meteorite.

The new dating of the Odessa impact shows that was not the case,
however. The Barringer Crater formed 50,000 years ago, about 13,000
years after Odessa.

Perhaps we are due for another one soon.

Dale Gnidovec is curator of the Orton Geological Museum at Ohio State
University.
Received on Tue 24 Jan 2006 06:08:18 PM PST