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Re: More Than Meteor Killed The Dinos
At 12:41 2006-10-26, Patti Kane-Vanni wrote:
I saw Gerta's talk at GSA, and as a non-expert I was intrigued, but saw
too many unanswered questions. See "The Philadelphia Inquirer" report on
the talk, a front-page story at:
The dino people were there! ..."Peter Dodson, a prominent University of
Pennsylvania paleontologist, then asked the obvious question. If there was
another meteor, where's the crater?
"We don't really know where it is," Keller admitted."...
It should be distinctly noticeable since it would be considerably larger
than Chicxulub (which is c. 200 km in diameter), and it can't have been
subducted, since the composition of the fallout shows that it must have hit
continental rocks, not basalt. Indeed the geology of the impact area must
be fairly similar to Yucatan for the chemistry to match. Also we know from
Chicxulub that there will be considerable deposits of impact breccias for
many hundreds of kilometers around the crater
I suppose about the only places where such a large and young structure is
likely to have remained undiscovered is under the ice on Antarctica or
Greenland and perhaps on the shelf around Antarctica.