Challengers to Clovis-age impact theory missed key protocols, study finds

http://phys.org/news/2012-09-clovis-age-impact-theory-key-protocols.html "Not separating samples of the materials into like-sized groupings made for an avoidable layer of difficulty, said co-author Edward K. Vogel, a professor of psychology at the University of Oregon. The new independent analysis�published this week in the online Early Edition of the Proceedings of the National Academy of Sciences�did, in fact, isolate large quantities of the "microspherules" at the involved sites where the challengers previously reported none. Lead author Malcolm A. LeCompte, an astrophysicist at Elizabeth City State University in North Carolina, said the findings support the climate-altering cosmic impact, but his team stopped short of declaring this as proof of the event. The Clovis-age cosmic-impact theory was proposed in 2007 by a 26-member team led by Richard B. Firestone. That team included University of Oregon archaeologists Douglas J. Kennett and Jon M. Erlandson. While other groups have found corroborating evidence of a potential cosmic event, other groups reported difficulties doing so. One group, led by Todd A Surovell of the University of Wyoming, did not find any microspherule evidence at five of seven sites they tested, including two previously studied locations where Firestone reported large numbers of microspherules. "In investigating the two common sites and a third tested only by Surovell's team, we found spherules in equal or greater abundance than did the Firestone team, and the reported enhancement was in strata dated to about 13,000 years before the present," LeCompte said. "What we've done is provide evidence that is consistent with an impact, but we don't think it proves the impact. We think there's a mystery contained in the Younger Dryas strata, and that we've provided some validation to the original research by Firestone's group." The particles in question, the team concluded, are terrestrial as was claimed by the Firestone group, and not of meteoric origin as claimed by other challengers including Surovell's group, and are similar to metamorphic material in Earth's crust. That determination was made using electron microscopy and spectroscopy. Read more at: http://phys.org/news/2012-09-clovis-age-impact-theory-key-protocols.html#jCp

Challengers to Clovis-age impact theory missed key protocols, study finds