Asteroid Blast Caused Rise of Civilization?

Did an asteroid explode over North America 13,000 years ago, setting off a millennium-long freeze, wiping out the continent's megafauna, decimating Stone Age civilizations and leading indirectly to the invention of agriculture in the Middle East?

That's what geologists will be talking about at this week's American Geophysical Union conference. (Okay, it's in Acapulco, so they might not make much progress....) The evidence: widespread sedimentary deposits of nanodiamond (!), iridium glass spheres that appear to have come from space. The deposits are also covered in a layer of charcoal that could have been left by wildfires caused by the explosion.

According to the new idea, the comet would have caused widespread melting of the North American ice sheet. The waters would have poured into the Atlantic, disrupting its currents.

This, they say, could have caused the 1,000 year-long Younger Dryas cold spell, which also affected Asia and Europe.

The Younger Dryas has been linked by some researchers to changes in the living patterns of people living in the Middle East which led to the beginning of farming.

Ice Age blast 'ravaged America' [BBC]
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Image: Znedek Burian*