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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: http://www.philly.com/mld/philly/living/health/15840611.htm

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.

Tommy Tyrberg