Geological evidence found in Ohio and Indiana (USA) in recent weeks is strengthening the case to attribute what happened 12,900 years ago in North America - when the end of the last Ice Age unexpectedly turned into a phase of extinction for animals and humans - to a cataclysmic comet or asteroid explosion over top of Canada.
     A comet/asteroid theory advanced by Arizona-based geophysicist Allen West says that an object from space exploded just above the earth’s surface at that time, sparking a massive shock wave and heat-generating event that set large parts of the northern hemisphere ablaze. Now University of Cincinnati Assistant Professor of Anthropology Ken Tankersley, working in conjunction with Allen West and Indiana Geological Society Research Scientist Nelson R. Schaffer, has verified evidence from sites in Ohio and Indiana that offers the strongest support yet for the exploding comet/asteroid theory.
     Samples of diamonds, gold and silver that have been found in the region have been conclusively sourced through X-ray diffractometry in the lab of UC Professor of Geology Warren Huff back to the diamond fields region of Canada. The only plausible scenario available now for explaining their presence this far south is the kind of cataclysmic explosive event described by West's theory.
     Tankersley was familiar through years of work in this area with the diamonds, gold and silver deposits, which at one point could be found in such abundance in this region that the Hopewell Indians who lived here about 2,000 years ago engaged in trade in these items. Additional sourcing work is being done at the sites looking for iridium, micro-meteorites and nano-diamonds that bear the markers of the diamond-field region, which also should have been blasted by the impact into this region.
     The timing attached to the comet/asteroid theory of about 12,900 years ago is consistent with the known disappearances in North America of the wooly mammoth population and the first distinct human society to inhabit the continent, known as the Clovis civilization. At that time, climatic history suggests the Ice Age should have been drawing to a close, but a rapid change known as the Younger Dryas event, instead ushered in another 1,300 years of glacial conditions. A cataclysmic explosion consistent with West's theory would have the potential to create the kind of atmospheric turmoil necessary to produce such conditions. "The kind of evidence we are finding does suggest that climate change at the end of the last Ice Age was the result of a catastrophic event," Tankersley says.

Source: University of Cincinnati (2 July 2008)