Younger Dryas impact event
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The Younger Dryas impact event is the name of a hypothesized impact event at the beginning of the Younger Dryas cold spell about 10,900 BCE. The impact seems to have occurred near the North American Great Lakes; the bolide may have disintegrated in the air.
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[edit] Evidence
The evidence for such an impact event is a layer of unusual materials (Nanodiamonds, magnetic grains, carbon spherules, magnetic spherules, charcoal, soot, fullerenes enriched in Helium 3, etc.) at the very bottom of the "black mat" of organic material that marks the beginning of the Younger Dryas. [1]
It is hypothesized that this impact event brought about the extinction of many North American large mammals. These animals included camels, mammoths, the short-faced bear and numerous other species. The markers for the impact event also appear at the end of the Clovis culture.[2]
[edit] 2007 AGU Meeting
On May 24, 2007, a session at the spring 2007 joint assembly of the American Geophysical Union in Acapulco, Mexico was held to discuss this hypothesis and reveal the evidence. [2]
[edit] PNAS Publication
On September 27, 2007, a paper[3] presenting the findings of the Acapulco group was pre-published online at the Proceedings of the National Academy of Sciences website. According to the study, the impact event may have led to an immediate decline in human populations in North America at that time.
[edit] See also
Video of the AGU Press Conference announcing the discovery
[edit] References
- ^ Dalton, Rex (2007-05-17). "Archaeology: Blast in the past?". Nature 447: 256–257. doi:. News article in Nature
- ^ a b Session Information, 2007 Joint Assembly, Paleoceanography and Paleoclimatology. American Geophysical Union. Retrieved on 2007-05-22. Includes links to abstracts.
- ^ Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. The National Academy of Sciences. Retrieved on 2007-09-30.
