Gerta Keller, Thierry Adatte and Wolfgang Stinnesbeck say that the field and laboratory evidence for an end-Cretaceous impact-kill just doesn’t add up…period.

"there is increasing evidence that the Chicxulub impact predated the end-Cretaceous mass extinction by about 300,000 years and did not cause the demise either of marine or terrestrial organisms1-3."

"The new evidence from Yaxcopoil-1, combined with the spherule
ejecta evidence from NE Mexico, indicates that the Chicxulub
impact predated the KT boundary by about 300k y. Chicxulub
therefore was not the cause for the KT mass extinction.
The KT impact crater still remains to be found.
--Gerta Keller, CCNet, 1 November 2003