[meteorite-list] Tagish Lake Meteorite May Hold Clues To Life

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:48:10 2004
Message-ID: <200110081546.IAA21164_at_zagami.jpl.nasa.gov>

http://www.rochesternews.com/1007story5.html

Space Rock May Hold Clues To Life

UR professor is part of team studying Tagish Lake meteorite

By Matthew Daneman
Democrat and Chronicle (Rochester, New York)

(Sunday, October 7, 2001) -- The hunk of space rock slammed into the icy
Canadian tundra in early 2000, leaving behind dozens of pounds of rubble.

Now a University of Rochester professor is poring over samples and finding
clues to the origins of life on Earth.

The meteorite that hit Tagish Lake, British Columbia, is one of the few
"which you could call Rosetta stones," said UR earth sciences professor
Robert Poreda, who is part of a team of scientists working on the project.

"Ninety-nine percent of meteorites really tell us nothing," he said.

"They just have normal chemistry and mineralogy."

The Tagish Lake meteorite, however, is like amber -- it has tiny bits of
ancient cosmic material trapped inside.

The research team is looking into the chemical makeup of the meteorite. And
their early results, published in the Sept. 21 issue of Science magazine,
indicate that meteorites such as Tagish Lake's may have played a key role in
the evolution of the Earth's atmosphere, Poreda said.

He and other scientists theorize that the atmosphere's noble gases -- those
which are inert or nearly so, such as argon and xenon -- are a mix of gas
that percolated up from the Earth's core and originated in meteorites that
smashed into the planet billions of years ago.

The ratio of noble gases in the atmosphere is different from those found
deep inside the Earth.

But they more closely match those found in tiny bubbles inside meteorites
like the one at Tagish Lake, Poreda said.

The team also is examining the Tagish Lake meteorite to see whether it
provides clues to the origin of organic carbon on Earth.

"The sticking point is to get from simple molecules, like amino acids, to
the complication of life," said Sandra Pizzarello, a chemistry professor at
Arizona State University and another member of the research team. "You just
put the puzzle one piece at a time in place."

During its fall, the Tagish Lake meteorite was visible as a bright fireball
throughout the Yukon, Northern British Columbia, parts of Alaska and the
Northwest Territories.

It's one of three significant carbon-rich meteorite finds in the past 50
years.

The others are Allende, which landed in Mexico in 1969, and Murchison, which
hit Australia in the same year.
Received on Mon 08 Oct 2001 11:46:49 AM PDT