7 August 2007
Comet theory may explain disappearance of ancient people in N.America
A theory put forth by a group of 25 geo-scientists suggests that a massive comet exploded over Canada, possibly wiping out both beast and man around 12,900 years ago, and pushing the earth into another ice age. University of South Carolina archaeologist Dr. Albert Goodyear based his study on ancient stone-tool artifacts he and his team have excavated from the Topper dig site in Allendale, as well as ones found in Georgia, North Carolina and Virginia. The tools, or fluted spear points, made by flaking and chipping flint, were used for hunting and made by the Clovis people, who lived 13,100 to 12,900 years ago, and from the Redstone people who emerged afterwards. The two points are distinctly different in appearance, with Redstone points more impressively long and steeple-shaped.
"I saw a tremendous drop-off of Redstone points after Clovis," said Goodyear. "When you see such a widespread decline or pattern like that, you really have to wonder whether there is a population decline to go with it." For every Redstone point, Goodyear says, there are four or five Clovis points. His findings are leading archaeologists from across North America to reexamine their fluted points, and their inventories are yielding similar results: a widespread decline of post-Clovis points that suggests a possible widespread decline of humans. "If the Redstone culture simply came right after the Clovis culture you'd expect at least as many Redstone points as Clovis ones. We just don't see that, and the question is why, and what happened to the people who made these tools?" said Goodyear.
Archaeologists have long known that the great beasts of the age – the wooly mammoth and mastodon – suddenly disappeared around the same time period, but little was known about their demise. It was thought to be the result of over-hunting by Clovis man or climate change associated with a new ice age. The notion that a comet collided with Earth and caused these events was farfetched until recently, when the group of scientists began looking for evidence of a comet impact, which they call the Younger - Dryas Event. In 2005, Arizona geophysicist Dr. Allen West and his team traveled to Topper site in hopes of finding concentrations of iridium, an extra-terrestrial element found in comets, in the layer of Clovis-era sediment. "They found iridium and plenty of it," said Goodyear. "The high concentrations were much higher than you would normally see in the background of the earth's crust. That tends to be an indicator of a terrestrial impact from outer space." The researchers also found high iridium concentrations at six other Clovis sites throughout North America, as well as in and along the rims of the Carolina Bays, the elliptically shaped depressions that are home to an array of flora and fauna along South Carolina's coast.
The Younger- Dryas Event suggests that a large comet exploded above Canada, creating a storm of fiery fragments that rained over North America. The fragments could have easily killed the giant mammals of the day, as well as Clovis man. "No one has ever had a really good explanation for the disappearance of mammoth and mastodon," Goodyear said. "The archaeological community is waking up to the Younger-Dryas Event. It doesn't prove that these Clovis people were affected by this comet, but it is consistent with the idea that something catastrophic happened to the Clovis people at the same time period."
The comet theory dominated the recent annual meetings of the American Geophysical Union held in Mexico. Goodyear's Clovis-Redstone point study and West's research on the comet were featured at the AGU meetings and by the journal, Nature. The comet will be the subject of documentaries featured on the National Geographic Channel and NOVA television late this fall and in early 2008.
Source: USC News (28 June 2007)
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