Research team claims no evidence of extraterrestrial impact causing Younger Dryas deep freeze

May 13, 2014 by Bob Yirka report
Trees were knocked down and burned over hundreds of square km by the Tunguska meteoroid impact. This image is cropped from the original, taken in May 1929 during the Leonid Kulik expedition. Credit: public domain

(Phys.org) —A team of researchers with members from several universities in the U.S. has published a paper in the journal Proceedings of the National Academy of Sciences, claiming that evidence supporting the notion that the Younger Dryas deep freeze was caused by an extraterrestrial impact or atmospheric explosion, is lacking. They go so far as to say that at this time, there is no real evidence of any such impact at all.

Scientists agree that something pretty big happened 12,800 years ago—the entire planet suddenly grew colder, allowing a cold weather blooming plant known as the Dryas octopetala to suddenly thrive. Mammoths in what is now the United States went extinct, so did the people that hunted them, the Clovis. Scientists have offered several ideas to help explain the sudden cold snap, which lasted over a thousand years, but thus far, no one has been able to prove what actually happened.

The best explanation, until now, came from a group of archeologists who claimed in a paper (and several others thereafter) published in 2007, that they'd found evidence of an or atmospheric explosion as the source of the deep freeze. It had left a thin layer of sediment over the world's land masses, they claimed, leaving evidence behind which they'd found. In this new effort, the research team says a closer look has revealed that of the 29 sites referenced by the earlier team, only 3 could be dated to 12,800 years ago, which they claim, totally refutes the teams' findings.

The 29 sites were spread across the globe, most based on sediments that the 2007 team had concluded had components that proved it came from an extraterrestrial source—tiny diamonds that had been formed due to the high pressure at impact, for example. Others sources consisted of soot and charcoal that were supposedly caused by fires ignited by the blast. The research team visited all 29 sites and performed radioactive analysis dating techniques on the found materials and report that only 3 of the sites could be dated closely to 12,800 years ago. The rest were either younger or older, some by as much as a hundred years. They also noted that in fact-checking the original paper from 2007 that some of the supporting work was weak—some dated material had come from other sites, and some were actually approximated using non-standard techniques.

All in all, the researchers report, there is no conclusive supporting the claim of an extraterrestrial impact causing the Younger Dryas deep freeze. Thus, more work must be done to find out what really happened.

Explore further: Study in Oklahoma panhandle finds additional active process producing nanodiamonds

More information: Chronological evidence fails to support claim of an isochronous widespread layer of cosmic impact indicators dated to 12,800 years ago, David J. Meltzer, et al. PNAS, DOI: 10.1073/pnas.1401150111

Abstract
According to the Younger Dryas Impact Hypothesis (YDIH), ∼12,800 calendar years before present, North America experienced an extraterrestrial impact that triggered the Younger Dryas and devastated human populations and biotic communities on this continent and elsewhere. This supposed event is reportedly marked by multiple impact indicators, but critics have challenged this evidence, and considerable controversy now surrounds the YDIH. Proponents of the YDIH state that a key test of the hypothesis is whether those indicators are isochronous and securely dated to the Younger Dryas onset. They are not. We have examined the age basis of the supposed Younger Dryas boundary layer at the 29 sites and regions in North and South America, Europe, and the Middle East in which proponents report its occurrence. Several of the sites lack any age control, others have radiometric ages that are chronologically irrelevant, nearly a dozen have ages inferred by statistically and chronologically flawed age–depth interpolations, and in several the ages directly on the supposed impact layer are older or younger than ∼12,800 calendar years ago. Only 3 of the 29 sites fall within the temporal window of the YD onset as defined by YDIH proponents. The YDIH fails the critical chronological test of an isochronous event at the YD onset, which, coupled with the many published concerns about the extraterrestrial origin of the purported impact markers, renders the YDIH unsupported. There is no reason or compelling evidence to accept the claim that a cosmic impact occurred ∼12,800 y ago and caused the Younger Dryas.

Press release

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User comments : 35

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Maggnus
5 / 5 (8) May 13, 2014
I find it interesting that the debate of impact/non-impact causing the younger Dryas seems to go back and forth almost every 6 months. Both sides give some compelling arguments, and there is a good deal of animosity between the two sides.

It will be interesting to see what the next proof will be, one way or the other.

Gotta love science!
ryggesogn2
1 / 5 (9) May 13, 2014
no one has been able to prove what actually happened.

But some are very eager to deny an asteroid impact.
Wonder why?
Vietvet
4.6 / 5 (9) May 13, 2014
no one has been able to prove what actually happened.

But some are very eager to deny an asteroid impact.
Wonder why?

With all I've read on the subject I haven't found anyone "eager to disprove it". Skepticism yes, but that's how science works.
Maggnus
5 / 5 (9) May 14, 2014
no one has been able to prove what actually happened.

But some are very eager to deny an asteroid impact.
Wonder why?
Because they don't think the evidence for an impact is compelling?

What, are they in a conspiracy to steal your freedoms and enslave us all with a socialist world government too?

My god you are a loon!!
ryggesogn2
1.5 / 5 (8) May 14, 2014
Skepticism yes, but that's how science works.

Since when?

Kuhn explained the opposition to the asteroid theory in "The Structure of Scientific Revolutions".
Maggnus
5 / 5 (6) May 14, 2014
Since when?

Kuhn explained the opposition to the asteroid theory in "The Structure of Scientific Revolutions".


How does Kuhn fit into this discussion? What, did you stumble across something someone wrote in a blog somewhere and just toss it in here because it prima facie fit some convoluted anti-socialist dogma you adhere to?

Kuhn's musings typify skeptical thought. Whether or not he is right (personally, I think he is not, but I admit I am not well versed in his theories) he does still attribute scientific progress to the questioning of established theory. That is the textbook definition of skepticism.

You should really take the time to understand the dogmatic positions you espouse, but you should especially take the time to understand the dogma of those you hold up as examples in support of your ignorant rantings.
ryggesogn2
1 / 5 (6) May 14, 2014
admit I am not well versed in his theories

Maybe you should do some homework before ranting on.
Maggnus
5 / 5 (6) May 14, 2014
admit I am not well versed in his theories

Maybe you should do some homework before ranting on.


Not well versed doesn't mean knowing nothing, something you should be well acquainted with. You are not well versed on most anything except paranoid rantings of New World Order imaginings.

Probably not even that.
ryggesogn2
1 / 5 (6) May 14, 2014
It's quite obvious Maggy doesn't understand Kuhn.
Maggnus
5 / 5 (6) May 14, 2014
It's quite obvious Maggy doesn't understand Kuhn.
How would you know?
CliffOcean
3 / 5 (2) May 15, 2014
This is an overview of the competing hypotheses as to what caused the YD event. Hope this helps!
wp.me/p4yGXN-7d
ryggesogn2
1 / 5 (5) May 15, 2014
It's quite obvious Maggy doesn't understand Kuhn.
How would you know?

It has not been demonstrated.
That's science, right?
Captain Stumpy
5 / 5 (5) May 16, 2014
It has not been demonstrated.
That's science, right?
Nope
you made a statement but there is no testable method, no description of possible and predicted results, no falsifiability, no repeatable/reliable test, and no conclusion. There is also no peer review, no publication and no benefit.

what you did was called personal conjecture without evidence
your comment about "not demonstrated" is stupid, because as it is YOUR comment, therefore the burden of proof lies upon you to prove it.

your comment also reveals your continued fallacious view of science which also reveals your contempt for empirical data... you despise what you cannot fathom, which makes you take out your frustrations on others more capable. a prediction which is demonstrated by many posts of yours over the course of the past year, especially in regard to physics and climate science.

whenever cornered you revert to lashing out with irrelevance, politics and ad hominem attacks

cue ryg
ryggesogn2
1 / 5 (5) May 16, 2014
you made a statement but there is no testable method,

It is based upon observation of mangy's comments of Kuhn and is acknowledgment of his ignorance of Kuhn.
Stump sounds like he is quite ignorant of Kuhn as well.
Whydening Gyre
5 / 5 (4) May 16, 2014
Not sure who Kuhn is - but I'm goin' with the theory that it's a ripple side effect in time and space of Tesla's purported broadcast energy experiment at Wardencliffe. Or the Philadelphia Experiment...
Dang.. Screw the starving Artist gig - I should write science fiction...:-)
Captain Stumpy
5 / 5 (4) May 16, 2014
Not sure who Kuhn is
@widening Gyre
Thomas Samuel Kuhn (July 18, 1922 – June 17, 1996) was an American physicist, historian, and philosopher of science whose controversial 1962 book The Structure of Scientific Revolutions was deeply influential in both academic and popular circles, introducing the term "paradigm shift", which has since become an English-language staple.

Required reading when you delve into forensic science and investigations... in fact, a lot of manufacturing companies read up on him too, especially in regard to Lean manufacturing and efficiency studies. getting stuck in a paradigm is the root cause of most failed investigations and misinterpretations of evidence during a case. its the manufacturing saying "it always worked before" attitude or "we've always done it this way"

maybe you SHOULD consider sci-fi? keep writing about rygg's posts, perfect starter for a story about a reject LOON in society... take it from there!
Captain Stumpy
5 / 5 (5) May 16, 2014
It is based upon observation of mangy's comments of Kuhn and is acknowledgment of his ignorance of Kuhn
@rygg-tard
so YOU are illiterate too? or just blatantly STUPID? he said "NOT WELL VERSED" which is VERY different than ignorant!
Stump sounds like he is quite ignorant of Kuhn as well
and so I am further justified in my post where I state
whenever cornered you revert to lashing out with irrelevance, politics and ad hominem attacks
You've just PROVEN my post. Thank you.
Dr_toad
4 / 5 (4) May 16, 2014
Not sure who Kuhn is
@widening Gyre
Thomas Samuel Kuhn (July 18, 1922 – June 17, 1996) was an American physicist, historian, and philosopher of science whose controversial 1962 book The Structure of Scientific Revolutions was deeply influential in both academic and popular circles, introducing the term "paradigm shift", which has since become an English-language staple.


A phrase I absolutely despise. Not quite as much as RigidSOB despises things, but still.
Whydening Gyre
5 / 5 (4) May 16, 2014
Not sure who Kuhn is

Ok, Wiki'd him after I made the comment. I. too, am not terribly fond of that phrase(sounds too pretentious).
I prefer -"Wow! Didn't see THAT one comin'.."
ryggesogn2
1 / 5 (5) May 16, 2014
Popper described a method of science, falsification, which he thought Einstein used well and which many hear believe they apply to AGW.
But AGW requires years to falsify.
Kuhn described a process where scientists don't falsify but work like a lawyer to collect evidence to support their assertion. And like lawyers, reject data that would falsify their theory.
Captain Stumpy
5 / 5 (6) May 17, 2014
described a process where scientists don't falsify but work like a lawyer to collect evidence to support their assertion. And like lawyers, reject data that would falsify their theory
@rygg

by all means, please show us the observed collected data that is peer reviewed and empirical that shows where all scientists (or even just climate science) is rejecting data that would falsify their theory! you mean like that latest post about Professor Bengtsson ?
better read this then: http://ioppublish...he-times
ryggesogn2
1 / 5 (6) May 17, 2014
"The University of Queensland in Australia is taking legal action to block the release of data used by one of its scientists to come up with the oft-quoted statistic that 97 percent of climate scientists agree that mankind is causing global warming.

Read more: http://dailycalle...1zvdUvDK

Nice little scam to stifle dissent.
ryggesogn2
1 / 5 (6) May 17, 2014
" In a new U.N. report released on Monday morning (Japan time) scientists come to a stark conclusion: Unless the world changes course immediately and dramatically, the fundamental systems that support human civilization are at risk.

If true, surely the world has the right to know every bit of information used for this conclusion, but that hasn't happened. "
"Just sent loads of station data to Scott. Make sure he documents everything better this time! And don't leave stuff lying around on ftp sites – you never know who is trawling them. The two MMs have been after the CRU station data for years. If they ever hear there is a Freedom of Information Act now in the UK, I think I'll delete the file rather than send to anyone."
http://wattsupwit...justice/
ryggesogn2
1 / 5 (4) May 17, 2014
Maggnus
5 / 5 (7) May 17, 2014
"The University of Queensland in Australia is taking legal action to block the release of data used by one of its scientists to come up with the oft-quoted statistic that 97 percent of climate scientists agree that mankind is causing global warming.


You lying piece of crap LOON! The U of Q sought an injunction against a denialist blogger who ILLEGALLY STOLE data and then threatened to publish the names of people who participated. Your misrepresentation is the height of hubris so typical of you.
ryggesogn2
1 / 5 (6) May 17, 2014
"But Cook's 97 percent consensus claim was rebutted in subsequent analyses of his study. A paper by five leading climatologists published in the journal Science and Education last year found that Cook's study misrepresented the views of most consensus scientists.

The definition Cook used to get his consensus was weak, the climatologists said. Only 41 out of the 11,944 published climate studies examined by Cook explicitly stated that mankind caused most of the warming since 1950 — meaning the actual consensus is 0.3 percent.

"It is astonishing that any journal could have published a paper claiming a 97% climate consensus when on the authors' own analysis the true consensus was well below 1%,"

Read more: http://dailycalle...20sl9Q1R
ryggesogn2
1 / 5 (6) May 17, 2014
"Dr Willie Soon, a distinguished solar physicist, quoted the late scientist-author Michael Crichton, who had said: "If it's science, it isn't consensus; if it's consensus, it isn't science." He added: "There has been no global warming for almost 17 years. None of the 'consensus' computer models predicted that.""
http://wattsupwit...-errors/
"Their definition of climate 'misinformation' was contingent upon the post-modernist assumptions that scientific truth is discernible by measuring a consensus among experts, and that a near unanimous consensus exists. However, inspection of a claim by Cook et al. (Environ Res Lett 8:024024, 2013) of 97.1 % consensus, heavily relied upon by Bedford and Cook, shows just 0.3 % endorsement of the standard definition of consensus: that most warming since 1950 is anthropogenic."
http://link.sprin...3-9647-9
ryggesogn2
1 / 5 (6) May 17, 2014
"Agnotology, then, is a two-edged sword since either side in a debate may claim that general ignorance arises from misinformation allegedly circulated by the other. Significant questions about anthropogenic influences on climate remain. Therefore, Legates et al. appropriately asserted that partisan presentations of controversies stifle debate and have no place in education."
http://link.sprin...3-9647-9
Stifling debate is the intent of falsely claiming 'consensus'.

Stifling debate is the intent of most who post here and by the site as they seldom promote any story that challenges AGW.
Hear no evil, see no evil, do no evil. Evil being questioning the AGW faith.
Captain Stumpy
5 / 5 (6) May 18, 2014
But Cook's 97 percent consensus claim was rebutted in subsequent analyses of his study. A paper by five leading climatologists published in the journal Science and Education last year found that Cook's study misrepresented the views of most consensus scientists
@ryg
this is your biggest problem. you find a QUOTE that talks about a published paper but instead you lik to dailycaller.com? WTF? WHERE is the paper rygg? where is that FULL PAPER for us to see? how about this? http://blogs.scie...sagrees/

2000 peer-reviewed publications
for global warming? 9136 agree against it? 1 disagrees
more like 99.99-0.01%
that MORE THAN AGREE's with the 97% by Cook and it is based upon actual published papers and is every bit as scientific (or more) than dailycaller.com

I WANT TO READ YOUR PAPER you refer to above.
Protoplasmix
5 / 5 (2) May 18, 2014
The research team visited all 29 sites and performed radioactive analysis dating techniques on the found materials and report that only 3 of the sites could be dated closely to 12,800 years ago. The rest were either younger or older, some by as much as a hundred years.

100 years? Why, that's off by nearly 0.8%, with 3 significant digits to boot. But there's a layer unique among all other layers that contains tiny diamonds, soot and charcoal – covering the entire globe? What other choices besides impact event would explain that?
Maggnus
5 / 5 (5) May 18, 2014
100 years? Why, that's off by nearly 0.8%, with 3 significant digits to boot. But there's a layer unique among all other layers that contains tiny diamonds, soot and charcoal – covering the entire globe? What other choices besides impact event would explain that?
I would like to see a clearer answer to that as well. It seems to me that the two sides should be locked in a room together with a couple of mediators and the evidence both for and against the impact theory be examined. There is a lot of conflicting claims, and that combined with the apparent animosity between the two sides, makes for a very confusing evidence trail.

The lack of a clear impact crater is problematic but not fatal. What other cause could have the same regional impact?
Protoplasmix
5 / 5 (1) May 18, 2014
The lack of a clear impact crater is problematic but not fatal.

True. Maybe it was an airburst. And/or the composition of the impactor may have been more like a comet than an asteroid. I think the strongest bit of evidence supporting the cosmic impact hypothesis is the discovery of a two-orders-of-magnitude spike in the platinum concentration in a clean and geologically undisturbed Greenland ice core sample, dating back to around 12,900 years ago, coupled with a high platinum/aluminum ratio which also supports a non-terrestrial cause (see http://phys.org/n...yas.html ). And one other idea I've not seen mentioned is the possibility that the impact record was erased or buried by the ensuing glacial activity.
MRyan
not rated yet May 18, 2014
Where, I can admit that I have not deeply followed this debate, (as it does appear to change leaders on a regular basis), my commentary here is not directly linked to this particular inquiry. I just felt a need to ask, how is it that this is a debate that has gone on and on, with no conclusive evidence for either theory, yet we today are arguing in the absolutes, as to the cause of climate change/shifts that has even less conclusive evidence? Now, before you all start in on me as being on one side or another, let me explain. I believe and recognize that the climate is changing, I also feel that it is ignorant to think that it could remain the same till the end of days. The terrain we are seeing, for the first time ever, being revealed from under ice caps, is showing us that the planet was a lot warmer before the ice age and would suggest that the planet would naturally revert back to that at some point.
Caliban
5 / 5 (2) May 18, 2014
'' ''


That's the single most truthful and intelligent thing that rygsukn' has ever posted here at PHYSorg.

Keep up the good work, moron.

Caliban
5 / 5 (2) May 18, 2014
The lack of a clear impact crater is problematic but not fatal.

True. Maybe it was an airburst. And/or the composition of the impactor may have been more like a comet than an asteroid. I think the strongest bit of evidence [...]And one other idea I've not seen mentioned is the possibility that the impact record was erased or buried by the ensuing glacial activity.


Not necessarily.

There is stil the "impact on the icesheet" hypothesis, which may appear, at first blush to not hold water, but, once you consider that the ice sheet was still a couple miles thick, can be accepted as at least a possibility.

This couldalso account directly for the sudden catastrophic meltwater flooding that strong supporting evidence seems to show as having occurred, which is in turn thought to have interrupted the AMOC and caused abrupt cooling in the NH.

It's a "best of both worlds" hypothesis, but --on balance-- appears to best account for all the evidence --or its absence.