[meteorite-list] Maine Crater Related to Dino-Killer Asteroid?

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:10:03 2004
Message-ID: <200304042343.PAA22101_at_zagami.jpl.nasa.gov>

http://dsc.discovery.com/news/briefs/20030331/crater.html

Maine Crater Related to Dino-Killer Asteroid?
By Larry O'Hanlon
Discovery News
April 3, 2003

The evidence is still
skimpy, but there is a chance that the dino
killer asteroid was not alone when it
walloped the Earth 65 million years ago.

A possible second crater, at least as big or
bigger than the famous Chicxulub crater off
Mexico's Yucatan peninsula, may have
been created by a second hit moments after
Chicxulub and off the coast of Maine.

"It probably is a crater, but we really don't
have age data," said marine geologist
Dallas Abbott Lamont-Doherty Earth Observatory at
Columbia University.

What makes Abbott suspect a crater is a
large and unexplained difference in the
magnetism of the crust in the Gulf of Maine.
Then there is an arrangement of ridges on
land that channel rivers and streams in
Maine and Massachusetts along arcs that
might be ridges of the western part of an
eroded crater, said Dominic Manzer a
NASA spacecraft engineer.

Abbott and Manzer presented their very
preliminary work on what they are calling
the Small Point crater late last week at a
regional meeting of the Geological Society of
America in Halifax, Nova Scotia.

Other asteroid and crater specialists are not
so optimistic that the Gulf of Maine will
yield a crater that corresponds with the end of
the dinosaurs &mdash; the Cretaceous-Triassic (K-T)
boundary 65 million years ago.

"There is no evidence of an impact event," said
David Kring of the Lunar and Planetary Laboratory at
the University of Arizona. What's more, if there were a
second impact, said Kring, there would be a second
blanket of debris at the K-T Boundary, which so far is
not there.

Abbott agrees that the evidence is slim at this point. In
fact, glaciers of past ice ages probably scoured away all
the real rock evidence on the surface long ago, she said.
That's why she hasn't tried to publish any official papers
on the matter.

Instead, she intends to start looking further south, in the
Martha's Vineyard area, for any impact-related rocks of the
right age that might have been dropped there after the glaciers
retreated.

If there was a double impact, said Manzer, it could have been
that the asteroid or comet broke up before hitting Earth,
leaving a rapid-fire line of craters, as has been seen on other
planetary bodies in the solar system.
Received on Fri 04 Apr 2003 06:43:48 PM PST