quote:
The paper also, bizarely, claims that "[t]he scale of biological turnover between the Cretaceous and Paleogene is nearly unprecedented in Earth history". And supports it with a reference neatly detailing the other mass extinctions... umm? And that's the real problem I have with impact explainations for the extinction of the dinosaurs - there is no evidence of impacts that co-incide with prior mass extinctions. It seems to me that the search for abiotic explainations of mass extinctions is missing the big picture: extinction seems to be a property of evolutionary systems.
??? What about the iridium anomaly near the Eocene-Oligocene boundary? Or the one at the Triassic-Jurassic boundary? Or shocked quartz at the same boundary? Or chondritic meteorite fragments and shocked quartz at the Permian-Triassic boundary? All of these are evidence of impacts.