Supposing, however, that Keller is correct, and the Chicxulub impact did not kill the dinosaurs, the finding begs the question as to what caused the mass extinction. Keller suggests that a yet-undiscovered impact on the scale of Chicxulub must have occurred, to explain the anomalous presence of iridium — an extremely rare element associated with certain types of meteorites — at the K/T boundary.
The odds, however, of more than one Chicxulub-sized impact are "beyond astronomical," Koeberl said. "America loves the underdog," he said. "That person doesn't have to be right."
Gulick and Koeberl said that they, along with about 99 percent of other impact crater specialists, do not consider there to be any debate about the Chicxulub impact having led to the K/T extinction event, and they have long since moved on to other crater research. Koeberl, for example, is working with the U.S. Geological Survey and the International Continental Scientific Drilling Program, which finished drilling a core from the 38-kilometer-wide Chesapeake impact crater in Virginia in December 2005. Koeberl and others are currently working to analyze the core to help them understand the crater's chemistry and structure and its impact on the region's geology.
It ought to be noted that the geologists involved have turned really ad hominem (keller included) over this. The evidence should speak for itself. However, this debate has gotten NASTY. I have a bad feeling that this one will not end until the participants have retired and fresh eyes can look on the evidence without the personal disccord.
However this part does bare repeating:
Gulick and Koeberl said that they, along with about 99 percent of other impact crater specialists, do not consider there to be any debate about the Chicxulub impact having led to the K/T extinction event, and they have long since moved on to other crater research.
Keller might just be flat wrong and seeing what she wants to. Either way personal biases are getting in the way of science. I guess that's just human though, huh?
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