Microscopic diamonds suggest cosmic impact responsible for major period of climate change

September 11, 2014, University of Chicago
Credit: NASA

A new study published in The Journal of Geology provides support for the theory that a cosmic impact event over North America some 13,000 years ago caused a major period of climate change known as the Younger Dryas stadial, or "Big Freeze."

Around 12,800 years ago, a sudden, catastrophic event plunged much of the Earth into a period of cold climatic conditions and drought. This drastic climate change—the Younger Dryas—coincided with the extinction of Pleistocene megafauna, such as the saber-tooth cats and the mastodon, and resulted in major declines in prehistoric human populations, including the termination of the Clovis culture.

With limited evidence, several rival theories have been proposed about the event that sparked this period, such as a collapse of the North American ice sheets, a major volcanic eruption, or a solar flare.

However, in a study published in The Journal of Geology, an international group of scientists analyzing existing and new evidence have determined a event, such as a comet or meteorite, to be the only plausible hypothesis to explain all the unusual occurrences at the onset of the Younger Dryas period.

Researchers from 21 universities in 6 countries believe the key to the mystery of the Big Freeze lies in nanodiamonds scattered across Europe, North America, and portions of South America, in a 50-million-square-kilometer area known as the Younger Dryas Boundary (YDB) field.

Microscopic nanodiamonds, melt-glass, carbon spherules, and other high-temperature materials are found in abundance throughout the YDB field, in a thin layer located only meters from the Earth's surface. Because these materials formed at temperatures in excess of 2200 degrees Celsius, the fact they are present together so near to the surface suggests they were likely created by a major extraterrestrial impact event.

In addition to providing support for the cosmic hypothesis, the study also offers evidence to reject alternate hypotheses for the formation of the YDB nanodiamonds, such as by wildfires, volcanism, or meteoric flux.

The team's findings serve to settle the debate about the presence of nanodiamonds in the YDB field and challenge existing paradigms across multiple disciplines, including impact dynamics, archaeology, paleontology, limnology, and palynology.

Explore further: Study examines 13,000-year-old nanodiamonds from multiple locations across three continents

More information: C. R. Kinzie, et al., "Nanodiamond-Rich Layer across Three Continents Consistent with Major Cosmic Impact at 12,800 Cal BP," The Journal of Geology 2014, 122(5). www.jstor.org/stable/10.1086/677046

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Maggnus
4.8 / 5 (5) Sep 11, 2014
I'm betting this will not be the last word on the subject. The evidence is beginning to accumulate more on the impact side then any other however, so the alternate theory promoters are facing a rather big hill of evidence to counter.

Kerr, Boslough and others may have to concede the possibility now.
Torbjorn_Larsson_OM
3.8 / 5 (5) Sep 11, 2014
What evidence, what "alternate theory"? Last round out of so many these loons (no good evidence for an impact, or its relation to the climate, human settling or large animal extinction) got trashed because of they still _lack evidence that convinces_.

If it can't be repeated, it is pathological science. This is such: "The hypothesis has been refuted by research showing that most of the conclusions cannot be repeated by other scientists, and criticized because of misinterpretation of data and the lack of confirmatory evidence.[4][5][6][7][8]" [ http://en.wikiped...pothesis ]

That is why the abstract is still trying to appease: "We describe an updated protocol for the extraction and concentration of NDs from sediment, carbon spherules, and ice, and we describe the basis for identification and classification of YDB ND polytypes, using nine analytical approaches."

Unfortunately not everything science is healthy science. This is one such case.
Torbjorn_Larsson_OM
4.5 / 5 (4) Sep 11, 2014
Like climate science there is no "sides" here, the consensus is massive.

And there isn't an "alternate theory" besides the impact one, because it is the null hypothesis of no impact. This is Science 101. I don't have to amass evidence that no impactor knocked down my house yesterday. If it happened, I would have to amass evidence that it did.

Similarly here. Impactors are rare, their effects on climate even rarer, et cetera.

So it is only the pathological science guys who needs evidence. Specifically they need extraordinary evidence because it is an extraordinary claim. But they can't find ordinary evidence at that. That has even made the encyclopedias, because they have been at it for so long.
Aligo
Sep 11, 2014
This comment has been removed by a moderator.
Maggnus
not rated yet Sep 12, 2014
What evidence, what "alternate theory"? *Snip* ..got trashed because of they still _lack evidence that convinces_.
I cannot tell from your liitle diatribe here which side you are proposing to defend. The site you cite and post the following quote from: "The hypothesis has been refuted by research showing that most of the conclusions cannot be repeated by other scientists, and criticized because of misinterpretation of data and the lack of confirmatory evidence." argue that the impact theory of mass extinctionlacks evidence. So are you are arguing for or against the theory? Then you say this:

That is why the abstract is still trying to appease:
That's the way science works. They are not trying to "appease" they are attempting to answer legitimate, pointed criticism.

Unfortunately not everything science is healthy science. This is one
You are entitled to your wrong opinion.
Maggnus
not rated yet Sep 12, 2014
Like climate science there is no "sides" here, the consensus is massive.
There is no "consensus" by any definition of the word. Quite frankly, the cause of the extinction event is not evident and the subject of much research. What is your stake?

And there isn't an "alternate theory" besides the impact one, because it is the null hypothesis of no impact.
Then I suggest you read your own cite Torbjorn. There are at least three competing hypothesis, and you need only read the article you seem to claim supports your contention that the impact theory is the "only" one to find that out.

Similarly here. Impactors are rare, their effects on climate even rarer, et cetera.
And, again, you seem to be arguing both sides of the coin. Do you agree with the impact theory or not?

So it is only the pathological science guys who needs evidence. *snip* But they can't find ordinary evidence at that.*snip* they have been at it for so long. Seems they have.
Maggnus
not rated yet Sep 12, 2014
@Torbjorn - and that is the whole point of the article; to wit, they have found evidence which prima facie supports their working theory that an impact event initiated the eventual extinction of North American megafauna. Have they convinced me? No, but I am intrgued, and it certainly seems to be a better working theory then volcanic eruption or the release of glacial lake Agassiz, which both have their own critiscisms to deal with. To simply dismiss this theory, or any others for that matter, is premature at best and anti-science at worst.

If you do not agree with the researchers conclusions, then argue their evidence Torbjorn. To denigrate their efforts simply because you don't agree with them is akin to climate denialism. (Hey you made the connection first!) You are arguing from a base of "it doesn't feel right" not "I disagree because...."

orti
1 / 5 (2) Sep 12, 2014
Some have proposed the Laurentine ice sheet (Lake Agassiz?) as the impact zone to explain the extensive North American damage, North Atlantic freshwater flood, and absence of a crater. Not sure of the status of that.
PS. 17 year pause (with 1001 excuses).

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