Compromise at K/T boundary

18 Nov 2011

Geoscientist Gerta Keller is extraordinarily consistent and has been a long time critic of the asteroid strike that killed the dinosaurs - based on geological dating of the strata (see Now, somewhat of a compromise seems to have been reached - there was more than one asteroid strike, not at the same time, but separated by 100s of thousands of years. It is geochronology that has caused this compromise as sedimentary layers are assumed to have been laid down over long periods of time. Keller has stuck rigidly over the years to this fact of geological theory and in so doing has been a persistent thorn in the flesh of the asteroid striking lobby. At one time, a few years back, it was suggested sedimentary layers at the time of the impact were laid down quickly - a fact that flew in the face of uniformitarian geology. Keller didn't like the asteroid strike as the one event that brought a mass extinction of species. She continually homed in on the Deccan Traps in India, evidence of a massive volcanic event at the end of the Cretaceous. She stuck rigidly to what she was taught in her geological lessons - and continued to maintain the two were not connected even when outsiders could plainly see there may well have been a connection. An asteroid impact in Mexico causing volcanism in India. Keller  emphasizes the role of volcanism triggering acid rain and climatic extremes that are a more likely explanation for the demise of the dinosaurs. However, it now seems an iridium layer has been found in India - at the time of the volcanism. As the Deccan Traps are dated via geochronology somewhat after the Chixulub impact the compromise is that a further asteroid struck thousands of years after the big one. In that way Keller has kept uniformitarianism intact - unthreatened by any suggestion that sedimentary layers can be laid down quickly.