America holds 12,900 year old nanodiamond-rich soilJanuary 2nd, 2009 - 10:57 am ICT by IANS
Washington, Jan 2 (IANS) Tiny particles of diamond dust that exist in sediments dating back to 12,900 years indicates earth’s impact with a rare swarm of carbon-and-water-rich comets or carbonaceous chondrites.These nanodiamonds, produced under high-temperature, high-pressure conditions during cosmic impacts and found in meteorites, are concentrated in six northern American sites across US and Canada.
Nanodiamonds can be produced on Earth, but only through high-explosive detonations or chemical vaporisation.
Last year a 26-member team from 16 institutions proposed that a cosmic impact event, possibly by multiple airbursts of comets, set off a 1,300-year-long cold spell known as the Younger Dryas, fragmented the prehistoric Clovis culture and led to the extinction of a large range of animals, including mammoths, across North America.
A team led by University of Oregon’s Douglas J. Kennett reports finding billions of nanometre-sized diamonds concentrated in sediments - about 10 to 2,700 parts per billion - in the six locations during digs funded by the National Science Foundation.
“These discoveries provide strong evidence for a cosmic impact event at approximately 12,900 years ago that would have had enormous environmental consequences for plants, animals and humans across North America,” said Kennett.
The Clovis culture of hunters and gatherers was named after hunting tools referred to as Clovis points, first discovered in a mammoth’s skeleton in 1926 near Clovis, New Mexico. Clovis sites were later identified across the United States, Mexico and Central America, said a Oregon release.
Clovis people possibly entered North America across a land bridge from Siberia. The peak of the Clovis era is generally considered to have run from 13,200 to 12,900 years ago. One of the diamond-rich sediment layers reported sits directly on top of Clovis materials at the Murray Springs site.
These findings appeared in Friday’s issue of Science.
- Ancient nanodiamonds proof of Earths impact with comets 12,900 years ago - Jan 02, 2009
- New evidence supports extraterrestrial impact theory - Jun 13, 2012
- New evidence indicates comet impacts triggered extinctions in North America 12,900 yrs ago - Jul 22, 2009
- New study challenges Clovis comet catastrophe theory - Sep 30, 2010
- Cosmic impact caused mass extinction event in North America 12,900 years ago - Jul 21, 2009
- No evidence of comet explosion over North America 13,000 years ago - Oct 13, 2009
- Comet-impact may not have killed mammoths, claim experts - Sep 06, 2010
- Meteor-impact may not have killed mammoths, great bears, claim experts - Sep 01, 2010
- Oldest American artefact unearthed dates back to 14,230 years - Nov 06, 2009
- Comets didn't wipe out early Americans 12,900 years ago - Oct 24, 2009
- Fossil evidence challenges Younger Dryas Impact theory - Jun 17, 2010
- Earliest American residents came at least 15,500 years ago - Mar 25, 2011
- Scientists disapprove American comet impact theory - Jan 28, 2009
- No evidence found for meteorite impact event 13,000 years ago - Dec 09, 2009
- Comets might have caused ancient American extinctions 13,000 years ago - May 07, 2008