Message #246196

[Desiree]

Topper site in middle of comet controversy

September 18, 2012 by Peggy Binette Topper site in middle of comet controversy Enlarge (Phys.org)—Did a massive comet explode over Canada 12,900 years ago, wiping out both beast and man in North America and propelling the earth back into an ice age? Ads by Google Tesla GPU Workstations - 8 Tesla C2070 GPUs in one quiet Workstation platform - www.velocitymicro.com/hpc That's a question that has been hotly debated by scientists since 2007, with the University of South Carolina's Topper archaeological site right in the middle of the comet impact controversy. However, a new study published today in the Proceedings of the National Academy of Sciences (PNAS) provides further evidence that it may not be such a far-fetched notion. Albert Goodyear, an archaeologist in USC's College of Arts and Sciences, is a co-author on the study that upholds a 2007 PNAS study by Richard Firestone, a staff scientist at the Department of Energy's Lawrence Berkeley National Laboratory. Firestone found concentrations of spherules (micro-sized balls) of metals and nano-sized diamonds in a layer of sediment dating 12,900 years ago at 10 of 12 archaeological sites that his team examined. The mix of particles is thought to be the result of an extraterrestrial object, such as a comet or meteorite, exploding in the earth's atmosphere. Among the sites examined was USC's Topper, one of the most pristine U.S. sites for research on Clovis, one of the earliest ancient peoples. "This independent study is yet another example of how the Topper site with its various interdisciplinary studies has connected ancient human archaeology with significant studies of the Pleistocene," said Goodyear, who began excavating Clovis artifacts in 1984 at the Topper site in Allendale, S.C. "It's both exciting and gratifying." Younger-Dryas is what scientists refer to as the period of extreme cooling that began around 12,900 years ago and lasted 1,300 years. While that brief ice age has been well-documented – occurring during a period of progressive solar warming after the last ice age – the reasons for it have long remained unclear. The extreme rapid cooling that took place can be likened to the 2004 sci-fi blockbuster movie "The Day After Tomorrow."

Read more at: http://phys.org/news/2012-09-topper-site-middle-comet-controversy.html#jCp