[meteorite-list] Museum Spotlights Colorado Meteorite 'Cotopaxi'

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:07:00 2004
Message-ID: <200210111632.JAA00622_at_zagami.jpl.nasa.gov>

http://www.insidedenver.com/drmn/state/article/0,1299,DRMN_21_1472528,00.html

Museum spotlights Colorado meteorite 'Cotopaxi'

'Cotopaxi' was found by treasure seekers scouring streambed

By Jim Erickson
Rocky Mountain News
October 11, 2002

Sharon and Richard Walker bought a metal detector to search for gold
nuggets, and 45 minutes into their first prospecting trip, they found
Colorado's 76th meteorite.

"All of a sudden, we hit it, and the metal detector went off really loud, a
strong piercing sound like a siren. It went, 'Rrrreeeeerr!' " Sharon Walker
said Thursday as she held the dark, rust-coated, 8.5-ounce space rock.

"We were pretty certain that it was something of importance because it was
so heavy," she said.

"It was heavier than a regular rock, and also a magnet attracted to it."

The discovery was made on Oct. 8, 2000, as the Walkers were scouring the
banks of a streambed on a friend's ranch near Cotopaxi, west of Pueblo in
Fremont County.

The Walkers approached Denver Museum of Nature & Science officials with
their find in May.

Researchers at the museum and UCLA confirmed that the Walkers' find is an
iron meteorite - the first iron meteorite discovered in Colorado in more
than 30 years.

Only 14 of Colorado's 76 meteorites are "irons."

Meteorites are fragments of asteroids, most of which orbit the sun between
Mars and Jupiter.

Seven percent of all the meteorites that fall to Earth are irons.

However, iron-rich meteorites dominate many museum collections because they
are easier to find than meteorites that don't react to metal detectors.

The Walkers' meteorite has been dubbed "Cotopaxi," a name that must be
approved by the Meteoritical Society, said Jack Murphy, curator of geology
at the Denver museum.A chemical analysis of the rock revealed that its
composition differs slightly from all other known iron meteorites, said John
Wasson, the UCLA chemist who conducted the tests.

There are about 700 known iron meteorites, he said.

"Cotopaxi is unique, and the more unique a meteorite is, the more valuable
it is scientifically," Wasson said Thursday.

"I would say this is one of the top 50 most scientifically important iron
meteorites, because of its unique composition."

In addition to iron, Cotopaxi contains a hefty dose of nickel and trace
amounts of gallium, arsenic, iridium and gold, Wasson said.

The meteorite probably formed 4.4 billion to 4.5 billion years ago and
likely fell to Earth within the past few hundred years, he said.

The Walkers, who are both federal investigators with the Defense Department
in Colorado Springs, say they've already rejected a couple of purchase
offers - one from a meteorite broker and another from a physician. One of
the offers was for $6,000.

"That didn't even get my interest going," said Richard Walker, 58.

"I think it's safe to say that it's worth more than gold."

The meteorite will remain at the museum until January.

The Walkers say they'll have it appraised before deciding whether to keep
it, sell it, or donate it to the museum.

The Walkers will display Cotopaxi and discuss its discovery Saturday during
Astronomy Day activities at the Denver museum.
Received on Fri 11 Oct 2002 12:32:25 PM PDT