http://geoweb.princeton.edu/people/faculty/keller/chicxpage1.html
1. Chicxulub predates the KT boundary and is not the cause for the end-Cretaceous mass extinction: Evidence from NE Mexico
FYI
I believe there was an FR topic on Keller. The fact is, impacts do occur, they have disastrous and widespread (depending on the energy involved) or planetary effects, and Keller is just regurg’ing Dewey McLean’s claims that volcanism was involved, while denying that the impact did anything. I find it kind of sad.
http://www.freerepublic.com/focus/f-news/891257/posts
http://www.freerepublic.com/focus/f-chat/983238/posts
http://www.freerepublic.com/focus/f-news/991929/posts
http://www.freerepublic.com/focus/f-news/1088837/posts
http://www.freerepublic.com/focus/f-news/1333931/posts
http://www.freerepublic.com/focus/f-news/1707717/posts
http://www.freerepublic.com/focus/f-news/1725888/posts
http://www.freerepublic.com/focus/f-news/1840136/posts
also mentioned in a post in the blog topic:
http://www.freerepublic.com/focus/f-bloggers/1607979/posts