Comet Storm: A hypothesis explaining megafauna extinction and the Younger Dryas cooling event

Posted: June 24, 2011 by tallbloke in Astronomy, Astrophysics, climate, Earthquakes, solar system dynamics, volcanos

I’ve seen this page mentioned a couple of times recently and took a read. It presents a convincing case for the cause of the Younger Dryas cooling event and the extinction of megafauna around 11,000 years ago.
Don’t be too daunted by the length of the page, the post is repeated from halfway down. It’s a gripping read, and I learned stuff about pyroclastic geology I didn’t know.


  1. the Earth sciences are still founded on that unquestioned ‘Gradualist’ assumption. But gradualism only works until something sudden happens…
    To know the details of catastrophism read Inmanuel Velikovsky´s “Worlds in Collision”:

  2. Roger Andrews says:


    Speaking as a professional geologist, if you didn’t know much about pyroclastic geology before you read this, then you know even less now.

  3. orkneylad says:

    Talkbloke, OT, but have you seen this?

    Universe’s highest electric current found:

    A COSMIC jet 2 billion light years away is carrying the highest electric current ever seen: 10-to-the-power-18 amps, equivalent to a trillion bolts of lightning. [this is a HUGE current: 1,000,000,000,000,000,000 amps]

    Philipp Kronberg of the University of Toronto in Canada and colleagues measured the alignment of radio waves around a galaxy called 3C303, which has a giant jet of matter shooting from its core. They saw a sudden change in the waves’ alignment coinciding with the jet. “This is an unambiguous signature of a current,” says Kronberg.

    The team ‘thinks’ magnetic fields from a colossal black hole at the galaxy’s core are generating the current, which is powerful enough to light up the jet and drive it through interstellar gases out to a distance of about 150,000 light years.


    No black hole required IMHO…..I think the stable door is truly open!

    “For one component of this jet we obtain for the first time a direct determination of a galactic-scale electric current, and its direction away from the AGN. Our analysis strongly supports a model where the jet energy flow is mainly electromagnetic.”


  4. malagaview says:

    Roger Andrews:
    Speaking as a professional geologist, if you didn’t know much about pyroclastic geology before you read this, then you know even less now.

    Roger: Please don’t stop there… it would be great to read some feedback from a professional geologist…

    Re-stating a question
    But missing from the responses so far is an answer from a trained Geologist. And in spite of the fact that they are dramatically obvious in satellite image data, I haven’t been able to turn up anything online, or in the literature, that indicates anyone has done any real science at any of them. Although with my limited access to the literature, that may simply be because I haven’t looked in the right places.

    I am looking for any solid data I can get. So far, I haven’t found them mentioned on any geologic map. Or in any piece of scientific literature.

    I’d like to reiterate the question. But this time I’m hopping to hear a plausible, well thought out, theory from a trained Geologist that describes a non-impact related process for their formation.

  5. tallbloke says:

    Hi Roger,
    I’m interested in hearing other explanations for the melted and refrozen features on the flat as a pancake Canadian shield which hasn’t seen volcanic action in 2.5 billion years. As a professional geologist, what can you tell us?


  6. tallbloke says:

    OL: Good spot! I’ll let the EU folk have a go then repost their interpretation.

    Edit: On second thoughts, let’s go for it. 🙂

  7. Tenuc says:

    This conjecture seems to be supported here…

    Nanodiamonds in the Younger Dryas Boundary Sediment Layer
    D. J. Kennett1, J. P. Kennett2, A. West3, C. Mercer4, S. S. Que Hee5, L. Bement6, T. E. Bunch7, M. Sellers7 and W. S. Wolbach8

    + Author Affiliations

    1 Department of Anthropology, University of Oregon, Eugene, OR 97403, USA.
    2 Department of Earth Science, University of California, Santa Barbara, CA 93106, USA.
    3 GeoScience Consulting, Dewey, AZ 86327, USA.
    4 National Institute for Materials Science, Tsukuba 305-0047, Japan.
    5 Department of Environmental Health Sciences/Center for Occupational and Environmental Health, University of California, Los Angeles, CA 90095–1772, USA.
    6 Oklahoma Archeological Survey, University of Oklahoma, Norman, OK 73019, USA.
    7 Departments of Geology and Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
    8 Department of Chemistry, DePaul University, Chicago, IL 60614, USA.

    “We report abundant nanodiamonds in sediments dating to 12.9 ± 0.1 thousand calendar years before the present at multiple locations across North America. Selected area electron diffraction patterns reveal two diamond allotropes in this boundary layer but not above or below that interval. Cubic diamonds form under high temperature-pressure regimes, and n-diamonds also require extraordinary conditions, well outside the range of Earth’s typical surficial processes but common to cosmic impacts. N-diamond concentrations range from ≈10 to 3700 parts per billion by weight, comparable to amounts found in known impact layers. These diamonds provide strong evidence for Earth’s collision with a rare swarm of carbonaceous chondrites or comets at the onset of the Younger Dryas cool interval, producing multiple airbursts and possible surface impacts, with severe repercussions for plants, animals, and humans in North America.”


    Refuted here…

    No evidence of nanodiamonds in Younger–Dryas sediments to support an impact event

    Tyrone L. Daultona, Nicholas Pinter, and Andrew C. Scott

    “The causes of the late Pleistocene megafaunal extinctions in North America, disappearance of Clovis paleoindian lithic technology, and abrupt Younger–Dryas (YD) climate reversal of the last deglacial warming in the Northern Hemisphere remain an enigma. A controversial hypothesis proposes that one or more cometary airbursts/ impacts barraged North America ≈12,900 cal yr B.P. and caused these events. Most evidence supporting this hypothesis has been discredited except for reports of nanodiamonds (including the rare hexagonal polytype) in Bølling–Ållerod-YD-boundary sediments. The hexagonal polytype of diamond, lonsdaleite, is of particular interest because it is often associated with shock pressures related to impacts where it has been found to occur naturally. Unfortunately, previous reports of YD-boundary nanodiamonds have left many unanswered questions regarding the nature and occurrence of the nanodiamonds. Therefore, we examined carbon-rich materials isolated from sediments dated 15,818 cal yr B.P. to present (including the Bølling–Ållerod-YD boundary). No nanodiamonds were found in our study. Instead, graphene- and graphene/graphane-oxide aggregates are ubiquitous in all specimens examined. We demonstrate that previous studies misidentified graphene/graphane-oxide aggregates as hexagonal diamond and likely misidentified graphene as cubic diamond. Our results cast doubt upon one of the last widely discussed pieces of evidence supporting the YD impact hypothesis.”

    Looks like the jury is still out on this vexatious and contentious issue.

    How little we actually know… 🙂

  8. tallbloke says:


    Refuted as in:

    We looked for needles in haystacks but only found little pointy bits of straw. Therefore the people who say they found needles must have mistaken bits of straw for needles.


  9. Dennis Cox says:

    Rex Dalton is no scientist. He’s a science journalist. And if you compare their shoddy stratigraphic work, and sample collection/preparation protocols, to the 2007 Firestone paper they set out to refute, you’ll see that it’s not even clear they sampled the same materials as the Firestone paper. The simple reason Pinter & Scott didn’t get the same result is because they didn’t really duplicate the experiment.

    But in fact, the ND’s in the Younger Dryas Boundary Layer have been confirmed. See: Discovery of a nanodiamond-rich layer in the Greenland ice sheet, by Andrei V. Kurbatov, et al.

    Nanodiamonds are only a very small part of the evidence collected so far. There is much hard evidence, yet to be published, but that is currently in peer review, that will blow you away.

  10. tallbloke says:

    Hi Dennis and welcome to the talkshop. Thanks for taking the time to come over and join this discussion. Your website was going to be my next port of call for further reading. If you’d like to recommend any particular posts for further reading into this subject, please feel free to add them here.

  11. Roger Andrews says:


    Thanks for your interest. Far too much here to go into in detail, so I’ll confine myself to the main points regarding the Chihuahua ignimbrites (CI for short).

    “The ablative event (that formed the CI) must have been only a few thousand years ago.” According to age dates the CI are between 23 and 38 million years old, and there’s no valid basis for disputing these estimates.

    “(The CI) were heavily ablated in a large, multiple airburst, impact storm. And over a period of just a few seconds.” The age dates say it took 15 million years. There are also basaltic lava flows between the ignimbrite units that certainly took more than a few seconds to form. The CI also contain a number of mineral deposits – some of which I’ve worked on – and these certainly didn’t form in the space of a few thousand years either.

    “the ignimbrite sheets should be as heavily weathered, and eroded, as everything else. And they should be under the alluvium that erosion would’ve produced.” If you drive across the state of Chihuahua you will spend most of your time crossing alluvial plains made up of fragments of CI. And if you go to Copper Canyon in the state of Sonora you will see a river that cuts through the CI to a depth of up to 8,000 feet. It’s hard to see how this much erosion could have happened in the last few thousand years too – unless of course you’re a Creationist.

    “no seismic, tomographic, ground penetrating radar, or any other data, has ever revealed a single one of those fault-graben-turned-fissures (that are thought to have been the conduits for the CI).” Aguirre-Diaz and Labarthe-Henandez ( identify several, and even show a picture of one.

    “And after a few thousand hours of studying their patterns of emplacement, I can tell you that those are are wind-driven patterns of motion frozen into those pristine pyroclastic rivers of flash melted stone”. The Google Earth pictures that accompany this statement show routine erosional features that could be used as examples in a geomorphology class. There’s no sign of “wind-driven patterns” in “pristine pyroclastic rivers”. The pictures in fact show that the dominant lithology is alluvium.

    There’s more, but that should be enough to be going on with.


    Sorry, I didn’t look at the Canadian shield stuff, partly because I’ve never worked there and partly because I’d had enough by the time I got to the end of the Chihuahua ignimbrites. However, I do have a Canadian geologist friend who has worked there, and I will solicit her opinion.

  12. tallbloke says:

    Roger, great stuff, it’s very valuable to have a professional opinion available right here among the regular contributors. The picture which I liked most was the crater spill that crossed over the ancient cut off river meander. I wonder if that is datable?

  13. Roger Andrews says:


    Thank you for your kind words. A professional opinion free of charge.too. I’m going to have to make sure it doesn’t become a habit.

    “The picture which I liked most was the crater spill that crossed over the ancient cut off river meander.” Which picture is this? I’d like to look at it.

  14. tallbloke says:

    This one:

    crater hunter

    Accompanying text:
    And at 44.644033, -112.076880, the ejecta that’s covering that late Pleistocene/Early Holocene meander provides an excellent stratigraphic horizon for dating the event. The two crater fields were probably formed in the same fall of fragments.

  15. Dennis Cox says:

    Hi TB,

    Any of them really. But I’m especially interested in getting discussions going on the numerous small craters in New Mexico, and west Texas. It seems to me that the simplest explanation for thousands of holes in the ground the size of a sports stadium, with raised rims, in a variety of terrains, all in the very same pristine condition, is a large cluster impact event of smaller fragments. But in the interest of due diligence, I’m exploring all options for their formation.

    The most amazing thing to me though, is that In the world according to Google Earth, they are dramatically obvious. Yet I can’t find any mention of them in refereed literature. How can such obvious geologic features not attract the attention of at least one curious researcher?

    On any other planetary surface in the solar system, no one would hesitate to call them impact craters.

    Mark Boslough, at Sandia Labs, is pretty much the chief skeptic of the of the YD impact hypothesis. His arguments are in a bit of a tight spot though. He’s correct that it’s impossible to model an impact event with a four mile wide bolide that has enough time in the atmosphere to break up, and scatter debris, over a continent sized area, without making a good sized crater somewhere. But that objection is more than answered in Clube & Napier’s work on the Taurid Complex. The YD comet was already a cloud of debris before it got anywhere near this fair world of ours.

    But that’s not the real rub for Dr Boslough. He’s also exactly right about the geo-ablative properties of very large air burst events. And since that’s the mechanism that produced the planetary scarring of the YD impacts, not the ballistic/kinetic impact of a single solid bolide, he can’t escape being convinced eventually.

    There are enough pristine geo-ablative melt formations within easy day trip driving distance of his home in Albuquerque, N.M to prove his work on ablative airburst phenomena a hundred times over. Those surfaces all date to the late Pleistocene. So it’s a good bet they are some of the blast effected materials of the YD impacts.

    It’ll be pretty darned ironic if the chief skeptic of the YD impact hypothesis winds up being the one who proves it once, and for all.

    That fact that Mark Boslough, and Horton Newsom, are correct about the ablative properties of large airbursts means that Roger Andrews is right. Much of what we thought we knew about pyroclastic geology has been as naïve as a children’s bedtime story.

    As for me, I’m starting to get an idea of how the outside observer in the story of the Blind Men and The Elephant felt. I see a few great scientists seemingly at odds, and bickering, yet whose work all dovetails together nicely in on unimaginably violent event.

  16. tallbloke says:

    Dennis; thanks for the further input.

    Many years ago I saw a documentary on TV about a ‘supervolcano’ event which caused the Yellowstone Caldera to be formed. It said that the effects went right across the north american continent, and the evidence was in sections of tree trunks embedded in the clay of river banks.

    Was that a later event, or a speculative theory, or a conflation of evidence with the event you are researching? I can’t remember how old the trees were according to the programme unfortunately.

  17. Roger Andrews says:



    The pic is of the Red Rock River in Southern Montana, which has incised a meander channel into what appear to be older valley gravels.

    I looked at the places where crater debris supposedly covers old meander channels. I found three of them, ranging in width from about 200 to about 600 feet. Two of them are right below crater-like features in the older gravels but the third doesn’t have a crater anywhere near it. This suggests that the features may be erosional.

    The crater-like features all show NNE elongation, and on Google earth at least they look like what we might expect a cluster of impact craters to look like. The problem, however, is that there are hundreds of them covering an area of maybe 10 square miles on the south side of the river but none on the north side. A meteor shower is unlikely to behave this selectively, so we can reasonably conclude that the distribution of craters isn’t compatible with a meteor shower origin. A more plausible explanation is that the craters are natural features that occur in a gravel unit which is present south of the river but not north.

    None of this of course conclusively proves that the craters aren’t impact craters. But someone could tell whether they are or not just by going there. And if they are impact craters there could be some vitrified fragments lying around which it should be possible to date.

  18. Dennis Cox says:

    Hi TB,

    As far as I know, the last eruption of the Yellowstone super volcano was the so called ‘Lava Creek’ eruption about 640,000 YA.

    It’s too far away, and far too small, to account for the more than 350,000 cubic miles of ignimbrites blanketing the terrains of North Central Mexico, and The Sierra Madre Occidental Mountains. And with only 15 calderas in the region, the source of most of it remains a problem.

    That they were emplaced in a pyroclastic density current there is no question. The theorists of the past had to come up with a way to get a few hundred thousand cubic miles of terrestrial material into atmospheric suspension, in a superheated pyroclastic density current at the same time. And until we saw the fragments of SL-9 hit Jupiter, no one could have imagined that so much heat, and pressure might come from above.

    The standard hypothesis proposes that they are related to the so called ‘Mid Tertiary Ignimbrite Flare Up’. when extensional forces in the middle of the continent are thought to have caused fault-grabens to transform into vast fissures, hundreds of miles long that opened up, belched out all those ignimbrites in a vast super-giant eruption that makes the Yellowstone look like a mouse breaking wind, and then closed again.

    But in spite of decades of mineralogical surveys, there is not one shred of seismic, tomographic, ground penetrating radar, or any other data, that indicates, or confirms, the existence of even one of the Fault-graben-turned-fissure vents. Much less a series of magma chambers so large that almost all of north central Mexico must be a super-giant caldera that makes the ones at Yellowstone, and Toba, look like puppies. And no one can explain the crazy mantle physics required for those magic trap-door rifting vents that opened, and closed without a trace.

    I welcome Mr. Andrews’s skepticism. And I hope it’s ok to ‘agree to disagree’. But since he thinks the Chihuahuan ignimbrites are nothing more than deposits of alluvium, I would hope he can refer us to refereed literature, or a good geologic map.

  19. tallbloke says:

    OK, I hope Roger will move from the specific to the general to respond to Dennis’ points about the sheer volume of material we are looking at here. I also hope Dennis will likewise respond to the question about the north/south side of the river Roger raised.

    I shall sit on the sidelines nursing my ignorance while you two have one of the polite and informative discussions the talkshop is famed and envied for generating. 🙂

    My thanks to both of you for taking the time to add your knowledge to this blog.

  20. Roger Andrews says:


    I think the red Rock River “craters” might be old pits dug by prospectors looking for alluvial gold. No way of knowing for sure without going there of course, but this would explain why they are elongated NNE (following alluvial channels) and also why they are all south of the river (gold in them thar hills to the south but none in them thar hills to the north.)

    Dennis Cox:

    If the Chihuahua ignimbrites are indeed only a few thousand years old then all the age dates run on them are wildly inaccurate. Correct?

  21. Dennis Cox says:

    On the subject of why there are no craters on the North side of the Red Rock River: I don’t see any reason to assume there must be any specific uniform order to the spacing of a cluster of fragments. Nor is there any reason to assume that any specific cluster size, density, or fragment distribution, must be the norm. Where the fragments hit, is simply where they hit.

    I’ve done a few impact experiments of my own. Not exactly lab conditions. But good enough to determine that the oval structures in southwest Montana are consistent with a barely supersonic, low angle impact, of about 30 degrees, and into wet sediments.

    Roger asked:

    If the Chihuahua ignimbrites are indeed only a few thousand years old then all the age dates run on them are wildly inaccurate. Correct?

    If you know of tested dates run on them I’d like to see those papers. Rick Firestone is pretty much the guru who wrote the book on radiometric dating of rocks. And he has headed up the isotope project at LBL for years. He tells me that it may not be possible to get a definative age for those materials.

    But yes, the way I see it, the dates given for those materials are overestimated by orders of magnitude.

  22. tallbloke says:

    Dennis, at the risk of displaying further ignorance, if the ignimbrites are as young as you believe, is there nothing beneath them that could help settle the matter? Like fossilized remains of datable species? Sounds like the whole area was well torn up by whatever happened there.

  23. malagaview says:

    Roger Andrews, Dennis Cox and Tallbloke

    Thank you GENTLEMEN for a wonderful discussion…
    It is a wonderful experience…

  24. Roger Andrews says:


    “But yes, the way I see it, the dates given for those materials are overestimated by orders of magnitude.”
    Thank you. Now on to question 2:

    The Chihuahua ignimbrites host a large number of gold deposits. How does a gold deposit form in the space of a few thousand years?

  25. Dennis Cox says:

    Good question TB. It’s going to come down to field work. Nothing trumps going there on the ground.

    No matter if it is volcanogenic, or exogenic, there are indeed many places where the interface between the melt, and the original terrains, should be intact, and easilly accessable. If the formation/emplacement event for the Chihuahuan ignimbrites was the geo-ablative impact storms of Taurid Progenitor. And the TP was the Younger Dryas comet, then there should be significant Siderophile, or Platinum group element enrichment at that horizon. And if there are charcoals from biomass that was cooked, and covered, by the event, we should expect that any C14 in that charcoal will jibe with the chemistry of the Younger Dryas boundary layer.

    In other words, we should expect alot of megafaunal fossils below that layer, but none above it.

  26. tallbloke says:

    Well Roger is our ‘man on the ground’ in that part of the world. Perhaps he knows of archeological or paleological work which might have found something?

  27. Dennis Cox says:

    Roger asked:

    The Chihuahua ignimbrites host a large number of gold deposits. How does a gold deposit form in the space of a few thousand years?

    Since the blast effected materials of a geo-ablative airburst event would consist of the materials of the original terrains, flash melted, ablated, and blown around a bit. And since rich gold deposits are a fairly common feature of the backbone of this continent, I don’t see a reason to assume the gold wasn’t there all along.

    But since any gold present in an ore sample will settle to the bottom of an assayers crucible, I would expect that an ablative airburst might have a concentrating effect on any gold in the melt. We should expect any gold to sink, and concentrate, at the bottom layers of a blast-driven flow of geo-ablative melt.

    I haven’t got a clue how a concentrated ore deposit might form ‘in the space of a few thousand years’. But I can imagine how it might happen in the space of just a few seconds.

  28. tallbloke says:

    Hmmm big nuggets at the bottom of the ignimbrite layer. Maybe I’ll come an give you a hand with that field work Dennis. You in Roger?

    Bed time for me in UK. Dreams of gold to you all.

  29. Tim Channon says:

    The river meander image.

    In my opinion this is older meanders.

    Reasons which in part come from image processing.

    The observation by Roger Andrews of asymmetry is pertinent. The north side is elevated and careful noting the altitudes suggests south side is ancient meanders except where the ground is slightly higher.

    I suggest the river is at the edge of a slight escarpment which it is trying to erode it. As it has moved north it has left behind older patterns.

    The signs of recent oxbow are in the area which is many older oxbow.

  30. Roger Andrews says:

    Hi all

    Just got back from an extended dinner with friends. Imbibed too much of the juice of the humble grape to respond coherently now so will do so tomorrow (Mexico time).

  31. Roger Andrews says:


    “Hmmm big nuggets at the bottom of the ignimbrite layer.” Sorry, pardner, but no bonanza. The gold particles in the gold deposits are dominantly micron-sized, and even in the highly unlikely event that there are big nuggets down there they will be buried hundred or thousands of meters deep. Come back in ten million years.

    Tim C:

    “The observation by Roger Andrews of asymmetry is pertinent”. With 100 craters (an underestimate) on the south side of the river and none on the north side, and assuming an equal impact probability on both sides, the chances that this pattern was caused by a meteor shower are about 10^12 to one against.


    “I haven’t got a clue how a concentrated ore deposit might form ‘in the space of a few thousand years’. But I can imagine how it might happen in the space of just a few seconds.” “We should expect any gold to sink, and concentrate, at the bottom layers of a blast-driven flow of geo-ablative melt.”

    Thank you. I’ll reserve comment for the moment and pass on to question three.

    Copper Canyon cuts through the ignimbrites to depths of up to 8,000 feet. How could this much erosion have occurred in only a few thousand years? And if it did, why is there no huge alluvial fan at the bottom of the Canyon?

  32. tallbloke says:

    Roger: Darnit! Oh well, back to work tomorrow for me then. Could the canyon have been formed by a rift in the last 13,000 years? Is there a fault line there? Could the canyon have pre-existed the event? How thick is the ignimbrite layer? Could the ignimbrites down the surface of the canyon sides be a surface layer only? Lots of silly questions, wait until Dennis has replied before bothering to answer. 🙂

    We’ve been invited to a BBQ, back later, play nice.

  33. Dennis Cox says:

    Got a GPS coordinate? And a link to a geologic map showing the location in question?

  34. Ulric Lyons says:

    Ok, so was it ET impacts that caused cooling at c.12900, 8200, 5200, 4200 B.P, or was it the Sun?

    If we can show that the cold episodes occur at a number of very similar heliocentric planetary analogues without exception, it would be decisive.

    Take the 1628BC cold event mentioned here:
    tree frost rings 1636/8BC:

    is 2 x 4627yrs after c.12900BP, and 12900 – 4627 is 8273.

    Anybody following me here might spot that with more accurate recent dating, we can calculate the earlier dates better by means of analogues.

    The duration of the YD is a big problem with impact theory too.

  35. Ulric Lyons says:

    tree frost rings 1626/8BC:

  36. Dennis Cox says:

    “The duration of the YD is a big problem with impact theory too.”

    Specifics please. In what way is the duration of the resulting climate disruption a problem with the impact hypothesis?

    Can you cite refereed literature? Or are you simply stating personal opinion?

  37. Roger Andrews says:


    I can answer your questions now.

    Could the canyon have been formed by a rift in the last 13,000 years? No. No rift there.

    Is there a fault line there? No, no fault line there either.

    Could the canyon have pre-existed the event? No. The canyon cuts through the ignimbrites, therefore the ignimbrites must have been there first.

    How thick is the ignimbrite layer? At least 1,400m (base not exposed).

    Could the ignimbrites down the surface of the canyon sides be a surface layer only? Not if it’s 1,400 m thick. The pic at shows at least 1,000m of ignimbrite exposed in the Canyon walls.

    Dennis: gives you geology and enough location data to find Copper Canyon on Google Earth.

  38. Roger Andrews says:

    Now a comment on the Younger Dryas. It’s visible only in the Greenland ice core records. There’s no equivalent event in the Antarctic ice cores, in the Devil’s Hole (Nevada) calcite record or in the DSDP sea bed cores, although the reading interval here is a little too coarse to be fully diagnostic. The implication is that the YD was confined to Greenland. It wasn’t a global event.

  39. Dennis Cox says:

    Are you saying that the Younger Dryas Cooling only happened in Greenland? And not in the rest of the northern hemisphere?

  40. Roger Andrews says:

    There’s some evidence that the YD cooling affected Northern Europe, but it doesn’t seem to have made it as far down as Nevada. I haven’t looked at Asia.

  41. Ulric Lyons says:

    @Dennis Cox says:
    June 26, 2011 at 5:37 pm

    “The duration of the YD is a big problem with impact theory too.”

    Specifics please. In what way is the duration of the resulting climate disruption a problem with the impact hypothesis?
    Can you cite refereed literature? Or are you simply stating personal opinion?

    Specifically, its accepted duration, which rather long to put down to one impact.

  42. Ulric Lyons says:


  43. Dennis Cox says:

    Roger said:

    “Now a comment on the Younger Dryas. It’s visible only in the Greenland ice core records. There’s no equivalent event in the Antarctic ice cores, in the Devil’s Hole (Nevada) calcite record or in the DSDP sea bed cores, although the reading interval here is a little too coarse to be fully diagnostic. The implication is that the YD was confined to Greenland. It wasn’t a global event.”/

    You lost me there Roger. You are the first person who has told me the YD cooling didn’t effect the entire northern hemisphere. I can introduce you to quite a few world-class paleo-climatologists who might take issue with that unfounded assumption. The Mammoths found in Siberia flash frozen into the permafrost, with buttercups in their stomachs, tell a different story too.

    Are we to ignore the materials in the YD boundary layer? And the Usello horizon in Europe? Or are we to disregard stratigraphy altogether? And focus only on ice cores?

    The YD impact hypothesis is as contentious as hell in the academic community. But while the exact cause of that sudden climate change remains contentious, the one fundamental piece of the puzzle that we don’t hear any of the mainstream planetary scientists, from either side of the isle, arguing about is whether, or not the YD cooling happened.

    Can you cite some literature that says it was a localized weather event specific to Greenland?.

  44. Roger Andrews says:


    Take a look at the ice core records from Epica and Vostok in the Antarctic, Huascarán in Peru and GISP2 in Greenland. The YD cooling is in fact visible in all of them (I was wrong on that, apologies) but it was far more intense in Greenland than anywhere else. Now look at the DSDP seabed core records from sites 980/981 and 984 in the North Atlantic. Neither of them show any compelling evidence for the YD. I will leave you free to make what you like of these results without further commentary from me.

    In the meantime, could you answer my last question on Copper Canyon?

  45. Dennis Cox says:

    I haven’t had a chance yet to look at Copper Canyon. We’re harvesting apricots here. As well as trying to get a new solar array for the house installed. And I’m a little buried in it. Give me a few days to study up, and give you a semi intelligent answer.

  46. Dennis Cox says:

    Specifically, its accepted duration, which rather long to put down to one impact.

    You are assuming that there was only one impact event. And that it was a small, and insignificant. one at that. Since impact research is an infant science, who is to say how big of an impact event it takes to produce a given level of climate disruption.

    I can’t say more at this time. But the hard evidence that’s in the peer review pipeline tells a different story. I’ll have a lot more to say when those papers see the light of day.

  47. Tim Channon says:

    ” There’s no equivalent event in the Antarctic ice cores, in the Devil’s Hole (Nevada) calcite record ”

    I thinks you will find neither can record such a fast event.

  48. Roger Andrews says:


    See my reply to Dennis above. The Devil’s hole record doesn’t record the YD but the Antarctic records unquestionably do, although at much reduced amplitude compared to GISP.

  49. tallbloke says:

    Hi Roger,
    The Antarctic record is much more ‘smoothed’ than the Greenland record, probably by diffusion of gas within the ice. This will flatten the shorter term response. This thread is worth a look:

    Here’s a cite to a Van Hoof paper:

    Atmospheric CO2 during the 13th century AD: reconciliation of data from ice core measurements and stomatal frequency analysis
    Article first published online: 25 AUG 2005

    DOI: 10.1111/j.1600-0889.2005.00154.x

    Atmospheric CO2 reconstructions are currently available from direct measurements of air enclosures in Antarctic ice and, alternatively, from stomatal frequency analysis performed on fossil leaves. A period where both methods consistently provide evidence for natural CO2 changes is during the 13th century ad. The results of the two independent methods differ significantly in the amplitude of the estimated CO2 changes (10 ppmv ice versus 34 ppmv stomatal frequency). Here, we compare the stomatal frequency and ice core results by using a firn diffusion model in order to assess the potential influence of smoothing during enclosure on the temporal resolution as well as the amplitude of the CO2 changes. The seemingly large discrepancies between the amplitudes estimated by the contrasting methods diminish when the raw stomatal data are smoothed in an analogous way to the natural smoothing which occurs in the firn.

  50. Dennis Cox says:

    Hi Roger,

    I had a chance to look at the Copper Canyon formation. It’s a little outside the actual impact zone I’ve identified. And from what I can see, the whole formation is mostly ancient volcanogenic. If any of the materials there are exogenic, and were emplaced by the impact storm, they would only be the uppermost, youngest, layer.

    But it does illustrate a problem I’ve been dealing with. Much of the impact zone was already a volcanically active area before the event. So that any rock specimens of airburst melt are going to be ‘contaminated’ so to speak, with materials of volcanic origin.

    The supportive ablative evidence for airburst origin of a fragment of ignimbrite will be in the mix of isotopes. Horton Newsom, at NMU’s meteoritics lab tells me the we should expect to see significant Platinum group, or siderophile element enrichment in any melt that has an extraterrestrial origin.

  51. Roger Andrews says:

    Hi TB:

    “The Antarctic record is much more ‘smoothed’ than the Greenland record”. I’m sitting here looking at the GISP2 and Epica temperature records and I can’t see much to choose between them. Both show about the same amount of short-term noise. The difference is in the longer-term fluctuations, which are about twice as GISP2.

    But we never see CO2 records from Greenland because they show much higher values than the Antarctic cores. This, of course, is because the Greenland ice is carbonate-contaminated. 😉

  52. tallbloke says:

    Hi Dennis. Have you made a map of the impact area? It would be in your own interests to do so I think. Otherwise you might get accusations (not here of course) that you are adjusting things in an ad hoc way to circumvent objections.

  53. Dennis Cox says:

    Yes, a map with the approximate impact zone is posted on a page called ‘The Mexican impact zone

  54. Roger Andrews says:


    “And from what I can see, the whole formation is mostly ancient volcanogenic. If any of the materials there are exogenic, and were emplaced by the impact storm, they would only be the uppermost, youngest, layer.”

    OK, let’s accept that the whole succession below the youngest volcanic layer isn’t exogenic. How much exogenic rock does that leave us with?

    It leaves us with the Divisadero tuff. This unit is only 10m thick at Copper Canyon, but according to Swanson et al ( it’s “a thin, erosional remnant of an extremely widespread unit of great local thickness and complexity”, and they’ve looked at the rocks and I haven’t so I’m going to take their word for it. So we’re still left with the problem of explaining how this extremely widespread unit of great local thickness got eroded down to remnants in the space of a few thousand years.

    And if only the Divisadero is exogenic then the total volume of exogenic ignimbrites in the Chihuahua volcanics shrinks dramatically (current estimates of +/- 400,000 km3 include all units, not just the topmost one.)

    Note also that Swanson et al identify no fewer than six calderas in their 100 x 60km study area. If this is representative of caldera density over the rest of the Chihuahua volcanic field – and I can see no reason why it shouldn’t be – then we have a total of 300 calderas, which is enough to explain the volume of all the volcanics in the field.

  55. Dennis Cox says:

    Thanks for the excellent link Roger. But in point of fact, almost the entire study area in that paper is a couple of hundred kilometers away from any of the formations I’ve been pointing at.

    Do you know of anything of comparable detail regarding the basin and range province between the Sierra Madre Occidental, and Oriental?

  56. Roger Andrews says:


    Copper Canyon is the type locality for studying the Chihuahua ignimbrites. There are no comparable studies farther east because there aren’t any 8,000ft deep canyons. However, there’s no significant change in near-surface volcanic stratigraphy as you go east, north or south of Copper Canyon. Just more ignimbrites.

    Two more papers you might read:

    And a couple of additional points:

    1. Your “Mexican Impact Zone” is displaced 150-200 miles east of the ignimbrites and only about a quarter of the exposed units inside it are actually ignimbrite.

    2. The mountain range in the google earth picture of the area 150 miles SSE of El Paso that you claim is ignimbrite is almost certainly a sedimentary rock (you can see the bedding quite clearly). Based on what I know of the geology of the area I’m pegging it as a Cretaceous limestone, age maybe 100 million years.

  57. Roger Andrews says:


    Retraction. On checking I note you didn’t claim that the mountain was ignimbrite. However, the material surrounding it is all outwash gravels, as far as I can tell.

  58. Dennis Cox says:

    See? That’s our point of disagreement. Although you are the first among the skeptics who didn’t think that curtain around that mountain was some kind of volcanic tuff.

    Outwash gravels is a new one. I wonder how you might get gravels to wash out in a perfect radial pattern like that?

    I’m still looking for a detailed geologic map of the area.

  59. Roger Andrews says:


    The radial pattern you think you see is caused by the fact that that mountain is surrounded by washes that form a ragged oval. This is purely a topographic effect, and there are numerous parallel examples elsewhere in the Basin-and Range province. I’ve been to the one at 32.07N, 110.00E (there’s another just a few miles to the northeast) and can confirm that the mountain here is surrounded purely by outwash gravels and not by exogenic material. To the best of my knowledge none of the other mountains in Arizona are surrounded by exogenic material either. If they were we certainly would have heard about it by now.

    I have no idea how the other “skeptics” you mention could have identified the gravels around your mountain as a volcanic tuff.

    I don’t think there is a detailed geologic map of the area, but even if there were I don’t see how it would help you respond to my question about erosion in Copper Canyon. But maybe I’m missing something.

  60. Dennis Cox says:

    That there are no geologic maps of the area makes it abundantly clear that the area is unstudied. Sentences that begin with, “Most geologists agree that_____”, aren’t the final authority in my world.

    So we disagree about that location. As for me, I’ll wait for detailed chemical analysis of materials from there.

    And yes, you are missing something. I did answer your question on Copper Canyon. I said I thought it was volcanogenic. Also, it’s hundreds of kilometers away from anything I’ve been writing about, or calling a geo-ablative formation.

    And I have never written a word about anyplace in Arizona.

  61. Dennis Cox says:

    By the way, when I Pasted the coordinates you gave me (32.07N, 110.00E) into the search bar in Google Earth, and Google Maps, it took me to a place about 270 kilometers south of Shaanxi, China. Which is also a pretty fair piece from anyplace I’ve been writing about. So I changed the ‘E’ to a ‘W’, and it took me to a mountain in Arizona that’s only 488 kilometers away. But it’s still not an example of the same geomorphology as as the mountain I wrote about.

  62. Roger Andrews says:


    Sorry about sending you to China. I inadvertently transposed the W to and E and didn’t notice. But if you ever do get round to visiting your mountain in Chihuahua I suspect all you’re going to find there is gravel outwash, just like Arizona.

    Final comments tomorrow.

  63. edwardt says:

    I’ve often heard the discussion often about the YD event as if it were a cold plunge from a warm cycle, but isn’t it really primarily about the warming pulse of the 1186yr cycle (in the NH) and it’s very rapid return to the previous cold baseline? Otherwise all of the previous 1186yr cycle spikes which have temp changes of roughly 1/2-2/3 of the interglacial/glacial differential are essentially YD events. Seems like we have to explain this transient phenomona, subsequently subtract it from the YD event in question, resulting in not too much to talk about IMO. Just saying that the majority of what appears as the YD event is really the rapid rise and equally rapid return of these 1186yr spikes. Origin anyone?

  64. tallbloke says:

    Hi Edward and welcome to the talkshop. Thanks for the informative graph. The spike in the GISP2 data prior to the YD cooling is of a similar magnitude and duration to the spikes between ~28-35k years BP. It was immediately followed by a longer duration lower amplitude warming before the plunge into the YD period. That period was followed by a very rapid rise in T of large magnitude which then stabilised in the current interglacial.

    The YD cooling has been seen as anomalous by climate scientists because co2 driven warming doesn’t fit this picture of strongly opposing forces too well. There doesn’t appear to be evidence of much larger then usual volcanic activity around that period which might provide a strong negative forcing on temperature, if the forcing attributed to volcanic activity were as large as the estimates say it is anyway. (I disagree).

    The impression is I have is one of great instability as opposing climatic forces battle for supremacy, with the switch to the warmer end of a bipolar state eventually winning. This is just one of several possible interpretations. In this thread, we have been exploring a hypothesis put forward by Dennis Cox that a cataclysmic event caused the YD cooling, as well as the disappearance of the North American megafauna and the human Clovis Culture.

    In other threads on the blog recently we have been looking at the Milankovitch cycles and how they might fit into the picture. I have also been developing a hypothesis that the global ocean mass absorbs, retains and releases huge amounts of energy on very long timescales, modulated by solar activity levels, ice extent and cloud cover changes.

    Your 1189 year ‘cycle’ is likely a combination of several cycles which trigger non-linear climate responses when their phaes coincide in certain configurations. There is a grand cycle of around 974 years concerning the internal distribution of angular momentum within the solar system which is probably involved. Fourier analysis of carbon isotope series reveal a ~2250 year quasi-cyclicity.

    It’s an open question, and one which deserves to be looked at from many angles, to lessen the likelihood of missing something important.

  65. edwardt says:

    Thanks for the welcome, great site Tallbloke, love the topics…cutting edge.

    Here is an image with the two events I was mentioning previously, lined up with kyrs offsets to compare the events to the YD event. Pretty similar IMO, which implies the YD event is not so unique, just the timing of the entrance to the interglacial makes it look out of place. (A combination of the 1168yr spike, and the obliquity signal I’m guessing.)

    I call these events the obliquity comb (just a word). When obliquity pops up every 41kyrs, these wiggles ride on top with a period of ~7200yrs. They are more readily seen in the vostok core at ~45krys.

    Curiously, the same signature is seen in the GISP2 core, though of opposite phase. Even occurs during the interglacial, though much attenuated (as climate sensitivity is not a constant).


  66. E.P. Grondine says:

    Hi Roger –

    Thank you for taking the time to comment on Mr. Cox’s “impact features”. Another geologist (Paul Heinrich) commented on some of them on the meteorite list.

    I’m afraid we’re dealing with a confirmatory bias in Dennis’s thinking, and it is delaying the search for real impact features from the Holocene Start Impacts.

    Your comment on YD cooling is well taken. My thinking is that the role of the Pacific Ocean in Ice Age cycling has been greatly overlooked, largely due to an European data bias.

  67. Dennis Cox says:

    Hi Roger,

    Mr Grondine got himself kicked off posting on The cosmic Tusk for his incesant ad hominem attacks. It’s a cryin’ shame he feels the need to continue his attacks here.

    The only thing that’s been delayed is Ed’s attempt to corral the search for impact structures to places he thinks people should be looking. He claims that Indian oral traditions contain accurate 13,000 year old memories of the Younger Dryas impacts. And that his own personal interpretations of those stories should be used to limit the search. But the only supportive reference he can provide for his claims is his own book. There is nothing whatsoever in refereed literature. And in spite of his claims he has never even identified one candidate location for field work

    Mr. Grondine is convinced that he is the only one who has the answers. But someone must have forgotten to explain for him that self referencing is not the way real science is done.

  68. Dennis Cox says:

    P.S. the only difference in the mountain I’m studying in Northern Mexico and the Sierra Madera Crypto Explosion Structure in southwest Texas is that at the crypto explosion structures in Northern Mexico the radial outwards flowing curtains of pyroclastic breccias  are perfectly pristine.

  69. Dennis Cox says:

    Thanks Roger,

    The most disruptive thing Firestone 2007 did was they went against the accepted belief systems of the “consensus”.

    A large part of the problem we deal with today in the study of impact science, and the YDB in particular, is one of confusing the mutual inter-assumptive reasoning of the consensus view with actual data driven science.

    Simply put, when questions are asked regarding impact science, and impact geomorphology, I believe that the generic answer that begins with “Most geologists agree that ______”, belongs in the very same category as “Most high priests, and scribes agree that the world is a flat disk carried through the universe on the back of a giant turtle while the sun, moon, and stars dance merrily across the heavens above.”

    It wasn’t that long ago that most geologists agreed that Barringer Crater in Arizona was volcanogenic, and poo pooed the very idea that large impact events have happened in the geologically recent past. It also wasn’t that long ago that “most geologists agreed” that the andesite found in the Pemex drill cores at Chicxulub was conclusive evidence of volcanism, not impact. The consensus held was that only volcanism could melt the rocks of the Earth, and produce andesite. But when planar fractures that could only have been produced by the shock of impact were detected in quartz grains of those cores, it was proven conclusively that the material is in fact, impact melt, and that Chicxulub is a giant crater.

    Our impact science is suffering from a collective manifestation of the Dunning Kruger effect. The consensus will be loath to admit it. But in fact, we simply have no idea how much we really don’t know at all. And while the actual data gets ignored, or denigrated because it refutes the assumptions of the consensus, the mutual inter-assumptive confabulations of the same consensus view gets elevated to the status of unquestioned dogma. Ever since Charles Lyell published ‘The Principles of Geology”, and in almost every case where catastrophic geomorphology has been proposed, the consensus has held to the more conservative uniformitarian view like a fundamentalist preacher clutching his bible until irrefutable data has been stuffed down their throats.

    As for me, I’ve found that learning progresses at a much faster when I begin with the realization that I haven’t got a clue, and then leave the door open to all data. The simple fact is that something catastrophic happened at the YDB. And we have no chance of unraveling just exactly what it was if we don’t first acknowledge that none of us really has anything more than a guess regarding what the hell happened in North America, and most of the Northern Hemisphere around 13,000 YA

    My point is simply that as often as not, the consensus is belief based, not data based, and that there is a critical, and fundamental difference between the statement that “most _____ists agree” about something, and the statement that “data has shown that”.

    Real science is data based, not belief based. So no matter the caliber of those who are in agreement with something for wont of a better theory, or lack of conclusive data, “consensus” is still just mutual inter-assumptive confabulation. And that just ain’t science. Show me the data.

    When I read a scientific paper I look to what they have found, or proven. And I tend to ignore for the most part what they believe, or only suppose. In other words no matter who is going into agreement with the “consensus”, or holding it up as the unquestionable authority, I’m not willing to accept anything but the data.

    In the field of impact research today, and the geomorphology of Earth impacts, I am convinced that there is no such thing as an “expert”. Only a few gifted specialists who are particularly advanced in their own narrow fields. We are only now beginning to scratch the surface. And there is clearly a lot of data that remains to be uncovered. So I remain to be convinced that those who are responsible for defining what the “consensus view” should be are working from a full data set.

  70. tallbloke says:

    OK, so you and we climate sceptics are unhappy about the presumed monopoly on contribution to knowledge operated by the consensuses in our respective fields.

    But leaving that aside for a while, what else is new? You mentioned some forthcoming papers early in this thread. Is this new stuff at Topper one of those? What else is moving forwards from your perspective?

  71. Dennis Cox says:

    The new stuff in the peer review pipeline I spoke of back then was finally published this year in the March issue of PNAS it is:

    Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis” by Isabel Israde-Alcántara et al. The paper can be seen as an upgrade of the Younger Dryas Impact Hypothesis. And it pretty much replaces Firestone 2007 as the Flagship paper for the YDIH

    I’ve been saying that north central Mexico bares the scars of a major multiple ablative airburst event for more than four years now. And that whatever it was came in at a low angle from the southeast. Lake Quitzeo, in central Mexico is the study location in that paper. And where the impact markers in the YD boundary layer have been difficult to identify every place else in the world, at Lake Quitzeo the impact layer is a full 10 centimeters thick. In other words it must be the closest site yet to the actual impact zone.

    Another thing I’ve been doing from the very beginning is to cite the Taurid complex, and the work of Clube & Napier as the astronomical model for the event I proposed. And as the most recent iteration of the YDIH, the Lake Cuitzeo paper now uses the astronomical model provided by W.M Napier in Palaeolithic extinctions and the Taurid Complex.

    Professor Napier points out that the breakup of comets is now recognized as a common path to their destruction. His work describes comets from the Taurid complex impacting as large clusters of small fragments. And when we look at images of fragmented comets like Comet Linear, or SW-3, we can see that he is probably correct.

    It’s time to consider the very real probability that we are not talking about a single bolide impact at all. But rather, a concentrated impact storm consisting of something like 10,000 Tunguska class airbursts in a matter of seconds.

    Lake Quitzeo is about 150 miles outside the southern end of the large oval shaped impact zone I’ve described. And the trajectory of the fragments would have meant that they had to pass directly overhead. And the fragments would’ve been well down into the atmosphere, as they passed overhead; close enough for a very powerful infrared pulse as the comet passed over. And in fact, the blast-effected materials found in the 10 CM thick impact layer there are perfectly consistent with something very large passing through the atmosphere directly overhead.

  72. tallbloke says:

    Excellent, thanks Dennis. Would you like to run a discussion here on these papers? Are we ok to reproduce figures etc and make a post out of them?

  73. Dennis Cox says:

    ‘Tis a subject that’s near and dear to my heart. I’d be delighted.

  74. tallbloke says:

    Great. I’ll put it together in the morning, sleepy time UK side.