Yesterday, EurekAlert served up a press release titled New blow for dinosaur-killing asteroid theory, reporting on Gerta Keller of Princeton, who says that the Chicxulub crater isn't really from the asteroid impact that killed the dinosaurs. Keller thinks the crater had nothing to do with the extinction event, and claims to have found evidence that the impact was as much as 300,000 years before the dinosaurs died out.
One or two of the quotes in the piece sounded kind of snotty for a scientific report, but I marked this down as something to look at later. Later in the day, Ethan "Nitro" Siegel weighed in with a long and image-laden post laying out the evidence in favor of the impact-extinction link, and comparing Keller to climate change deniers and creationists.
Who's right? Siegel makes a pretty good case that the preponderance of evidence favors the impact theory. I'm inclined to favor that as well, for sentimental reasons, but I really don't have the background to judge. Mostly, I just wanted to note the post in question and say that if you're not already reading Starts With a Bang, you should check it out.
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Being a geology student and thus on the fringes of the field, so to speak, I've gotten the impression that the hypothesis of an asteroid impact causing a mass extinction all by itself is mostly in doubt. It's likely that the Deccan Traps eruptions played a role as well, and may well have been the ultimate cause. I do know that this debate has been alive and well in the geologic community for a long time.
Karen said
When the asteroid struck, massive shock waves would have radiated out from the point of impact then come to a focus on the opposite side of Earth. Could this have caused the formation of the Deccan Traps?
An observation: the word 'denialism' gets tossed around a lot by people who seem to hold dogmatic views on a variety of issues. Its most common uses (Holocaust, Evolution) were, in my view appropriate. However now its being extended to people who question the completeness of global climate models, or, for crying out loud, the extinction of the dinosaurs. Is anyone else concerned that the over use of this term is anti-scientific? It strikes me that its meaning has become "shut up, I'm right and you're wrong". Good scientists should be skeptical, particularly of their own theories and experimental results.
Richard Simons said
When the asteroid struck, massive shock waves would have radiated out from the point of impact then come to a focus on the opposite side of Earth. Could this have caused the formation of the Deccan Traps?
I don't know much about the current thinking on the formation of flood basalts, but I don't think shock waves, however massive, could cause that kind of volcanic eruption. Shock waves might start an eruptive cycle that was already primed and ready to go, though. Maybe a real geologist will stop by to comment!