Nano-Diamond Discovery Suggests a Comet Impact Killed the Mammoths

By Eliza Strickland | January 5, 2009 10:10 am

comet impact lineMinuscule diamond fragments found in a sediment layer dating from thousands of years ago are bolstering the theory that a catastrophic comet impact wiped out many forms of life in North America, including what are thought to have been the first human settlers of the continent, the so-called Clovis people. The nano-diamonds are buried at a level that corresponds to the beginning 12,900 years ago of the Younger Dryas, a 1,300-year-long cold spell during which North American mammoths, saber-toothed cats, camels and giant sloths became extinct. The Clovis culture of American Indians also appears to have fallen apart during this time [Reuters].

The new study adds evidence to the controversial theory, but some skeptics are not convinced. “The whole thing still does not make sense, and there are lots of contradictions,” said Christian Koeberl, a professor of geological sciences…. His chief reservation is that there is no crater. “A body of this size does not just blow up without a trace in the atmosphere,” Dr. Koeberl said. “Physics won’t have it” [The New York Times]. In reply, supporters of the theory say that some of the comet fragments may have exploded in midair, while others may have hit an ice sheet that was several miles thick, lessening the possibility of a crater forming.

In the study, published in Science [subscription required], researchers used transmission electron microscopy to identify nanodiamonds at a number of North American sites, from Arizona to South Carolina to Manitoba, Canada. “We’ve discovered nano-diamonds that are not normally produced through average processes on the surface of the Earth,” said [study coauthor] James Kennett…. “They indicate there was an extra-terrestrial event on Earth 12,900 years ago” [BBC News]. The tiny diamonds are encased in carbon spheres that form through instantaneous melting, and the diamond crystals have a hexagonal pattern rather than the usual cubic structure, indicating that they were formed by intense heat and pressure. Such diamond crystals have been found only within meteorites at at impact craters, the researchers say.

The causes of the woolly mammoth extinction, the collapse of Clovis culture and the onset of the cold snap have long been debated. But only the impact theory accounts for the simultaneous occurrence of all three, said Doug Kennett [BBC News]. He says that the comet fragments’ explosions and impacts could have destabilized the massive ice sheet that covered much of North America, sending a burst of fresh water into the North Atlantic and interfering with the ocean currents that play an important role in climate.

Related Content:
DISCOVER: Were the First Americans Wiped Out By an Asteroid?

Image: Doug Kennett

  • http://na Grace

    now that is cool. it would explain the sudden death of the Clovis culture, and wooly mammoth dissapearances. i’m not so much an expert on this as i am on global warming, this is one cool discovery.

  • http://google rosemary

    i think that whoever thought of the idea that pluto is not a planet they are, stupid, dumb, retarded, mean, and a lier.

  • http://google rosemary

    just to let you know i am not trying to be mean but i think you are stupid to say pluto is not a planet.

  • Ryan

    Not to be a smart alek or anything but technically they didnt say pluto wasn’t a planet but a dwarf planet. So it still is a planet but it just doesnt fall under the same catagory as some other planets:)

  • Jose

    What does Pluto even have to do with this? Its completely irrelevant to say that on an article that doesn’t have anything to do with Pluto, find something regarding Pluto and complain there.

  • Dennis Cox, Fresno, Ca.

    It’s an interesting story. But when a layman discovers where it exploded no one want to hear it.
    The epicenter of the main explosion was Lake Guntersville Ala. Check it out with Google Earth.

  • Gary Ansorge

    What was that Randy Newman song???Oh yes,” This world you love so much just might kill you,,,”.
    Should perhaps be rephrased as “This Universe,,,etc.”

    Comet/asteroidal impacts are a part of the chaotic aspect of reality. All any living being can do is roll with the punches. Those who roll the best,,,survive.

    Excellent detective work.

    Gary 7

  • Amitava Banerjee

    Is it possible to have nanodiamonds in the Earth through high P-T metamorphic processes ? Or it can only form through impact?

  • abby

    this is fasinating after i saw nova “last extinction” i got so interested in this, and he came up with the idea comparing it to when a comet hit Jupiter and shattered into pieces in Jupiter.

  • chris

    awesome discovery

  • chris

    Its a really cool discovery. Somethign from 12,900 years ago.

  • http://Discovermagazine Bobo


    Currently nanodiamonds of terrestial origin are found in high percentage of cuboidal or rectangular lattice, pyrimidal cleavage etc.

    Extraterrestial nanodiamonds have a high percentage of hexagonal crystal lattice.

    The iridium signature and the nanodiamonds (hexagonal) found in these very discrete soil bands and ice bands of 12,500 year age are 2 key evidence points in the theory.

    The fossil record drop off and the evidence of huge fires and sudden, massive climate cooling are others. Don’t really need a crater if Earth got ‘sand-blasted’. I like the hit a glacier scenario too.

    Life is hazardous to our health.

  • http://NA Bruce C (Cincinnati)

    The discovery of the hexagon shaped NANADIAMONDS in soil samples and core samples may be one of the most significant brekthroughs in terrestrial Metorite IMPACT science. Even if there is no evidence of a crater or any significant amounts of iridium, there could be several theories which could explain the event. A high altitude burst could cause fragments to scatter over a large area wher 13,000 years of erosion and weather may have hidden the evidence. An Atmospheric burst over the deep ocean would still send significant amounts of particles for 1,000 of miles and still very little impact evidence. Outstanding Discovery.

  • YouRang

    I thought the definition of diamond was cubic crystal structure–that hexagonal structure was graphite.

  • cliff

    I have an arrowhead which I found in the Yadkin River Valley of N. Carolina that appears to have iron fragments imbedded in it. Upon looking closer with a magnifying glass there are some very small sparkling objects there also. The artifact appears to be Hardaway which was a few thousand years after the Clovis. I am wondering if these “splarkling” things could possibly be nano-diamonds and the iron imbedded in the projectile point could possibly be from a meteorite? Would like to know where to find out.

  • nitin singh

    plz,send me some nano diamond’s reff. book in my email I.D.

  • Robert Manley Lucas

    Ciff, The arrowhead sond as if it were made of a shard of a “thunderstone”, which would have crystals. If you have a picture of high resolution one might tell. I have a picture of some I have found in NC near the Carolina Bays (google them)

  • black nightstand furniture

    What is the purpose of this informative article if you don’t brain me requesting?


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