In The Age (via Political Theory Daily Review):
DID an extraterrestrial impact set off a catastrophic chain of events that led indirectly to the dawn of agriculture in the Middle East nearly 13,000 years ago?
It may sound like something out of a Hollywood science fiction movie, combining the global disaster themes of Deep Impact and The Day After Tomorrow. Yet the evidence looks increasingly solid.
There is little doubt that a megaflood of glacial meltwater cascading off the North American continent into the Atlantic Ocean spurred the birth of agriculture and civilisation in the Middle East around 12,900 years ago. What was not known until recently is that this event, known as the Agassiz megaflood, may have been triggered by a comet exploding above or plunging into the ice sheet north of the modern Great Lakes.
According to two geologists at the University of Oregon, Dr Douglas Kennett and Dr Jon Erlandson, there is reason to believe a large chunk of a comet exploded above or crashed directly into the Laurentide ice sheet, rupturing the ice dams on the easterly margin of Lake Agassiz and causing frigid water to flood into the North Atlantic.
The primary evidence consists of a carbon-rich layer of soil, dating to around 13,000 years ago, found at 50 Clovis-age sites across North America. The Clovis people, the first wave of human colonists to reach North America from Siberia, had only recently colonised the Americas.