From: LARRY KLAES (ljk4@msn.com)
Date: Sun May 12 2002 - 13:47:03 PDT
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From: baalke@jpl.nasa.gov
Sent: Sunday, May 12, 2002 1:01 AM
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Subject: What Caused Argentina's Mystery Craters?
http://news.nationalgeographic.com/news/2002/05/0509_020509_glassmeteorite.html
What Caused Argentina's Mystery Craters?
By Ben Harder
National Geographic News
May 9, 2002
For more than a decade, planetary scientists have been puzzling over a
mixed bag of meteorite evidence scarring Argentina's plains. They gradually
pieced together clues to reconstruct what seemed to be a rough-hewn but
generally accurate account of a prehistoric meteorite impact.
A mere 10,000 years ago, scientists deduced in the original theory, a sizable
meteorite came hurtling through the atmosphere at a bizarrely low angle,
smacked the ground with a glancing blow, and broke into numerous pieces
that gouged separate, miles-long scars in the Argentine earth.
But now a fresh analysis has turned that theory on its head. The mysterious
craters in Argentina may not have been caused by meteorites at all, but
rather by the wind, sculpting the ground over a long time. Discovered in some
of these crater-like trenches, ironically, were the remains of real meteorites
that crashed into Earth over widely separated time periods. They struck at
different angles and produced spectacularly different results-including, in the
case of one, a widespread shower of molten glass.
The evolving interpretation of Argentina's mysterious craters, University of
Arizona planetary scientist Jay Melosh writes in the May 10 issue of the
journal Science, "is both less and much more than [its] discoverers originally
believed."
Full story here:
http://news.nationalgeographic.com/news/2002/05/0509_020509_glassmeteorite.html
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