Six North American sites hold 12,900-year-old nanodiamond-rich soil

Jan 01, 2009

Abundant tiny particles of diamond dust exist in sediments dating to 12,900 years ago at six North American sites, adding strong evidence for Earth's impact with a rare swarm of carbon-and-water-rich comets or carbonaceous chondrites, reports a nine-member scientific team.

These nanodiamonds, which are produced under high-temperature, high-pressure conditions created by cosmic impacts and have been found in meteorites, are concentrated in similarly aged sediments at Murray Springs, Ariz., Bull Creek, Okla., Gainey, Mich., and Topper, S.C., as well as Lake Hind, Manitoba, and Chobot, Alberta, in Canada. Nanodiamonds can be produced on Earth, but only through high-explosive detonations or chemical vaporization.

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. The team's paper was published in the Oct. 9, 2007, issue of the Proceedings of the National Academy of Sciences.

Now, reporting in the Jan. 2 issue of the journal Science, a team led by the University of Oregon's Douglas J. Kennett, a member of the original research team, report finding billions of nanometer-sized diamonds concentrated in sediments -- weighing from about 10 to 2,700 parts per billion -- in the six locations during digs funded by the National Science Foundation.

"The nanodiamonds that we found at all six locations exist only in sediments associated with the Younger Dryas Boundary layers, not above it or below it," said Kennett, a UO archaeologist. "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."

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, N.M. Clovis sites later were identified across the United States, Mexico and Central America. 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.

News release on the 2007 paper is available here, with link to a copy of that paper.)

Source: University of Oregon

Explore further: Scientists fabricate defect-free graphene, set record reversible capacity for Co3O4 anode in Li-ion batteries

add to favorites email to friend print save as pdf

Related Stories

There's something ancient in the icebox

Apr 17, 2014

Glaciers are commonly thought to work like a belt sander. As they move over the land they scrape off everything—vegetation, soil, and even the top layer of bedrock. So scientists were greatly surprised ...

Solar variability and terrestrial climate

Jan 11, 2013

(Phys.org)—In the galactic scheme of things, the Sun is a remarkably constant star. While some stars exhibit dramatic pulsations, wildly yo-yoing in size and brightness, and sometimes even exploding, the ...

Cosmic rays reveal event in Earth's magnetic field history

Nov 29, 2012

41 000 years ago, the Earth's magnetic field faded and practically disappeared, leaving our planet unprotected from the bombardment of cosmic rays. Evidence for this event has been found in ocean sediment cores by a team ...

Recommended for you

Copper shines as flexible conductor

Aug 22, 2014

Bend them, stretch them, twist them, fold them: modern materials that are light, flexible and highly conductive have extraordinary technological potential, whether as artificial skin or electronic paper.

Nanoparticles may aid oil recovery, frack fluid tracking

Aug 22, 2014

Two Colorado State University researchers are examining how nanoparticles move underground, knowledge that could eventually help improve recovery in oil fields and discover where hydraulic fracking chemicals ...

Nanostructure enlightening dendrite-free metal anode

Aug 19, 2014

Graphite anodes have been widely used for lithium ion batteries (LIBs) during the past two decades. The replacement of metallic lithium with graphite enables safe and highly efficient operation of LIBs, however, ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

WolfAtTheDoor
5 / 5 (1) Jan 02, 2009
Great, I can hear my wife now... "I want some jewelry for Christmas, and none of that 'nanodiamond' B.S. that you usually get me!"