Younger Dryas climate event solved via nanodiamonds – it was a planetary impact event

From the University of California at Santa Barbara -By Julie Cohen |

Most of North America’s megafauna — mastodons, short-faced bears, giant ground sloths, saber-toothed cats and American camels and horses — disappeared close to 13,000 years ago at the end of the Pleistocene period. The cause of this massive extinction has long been debated by scientists who, until recently, could only speculate as to why.

younger_dryas_graph

This graphic is used to illustrate the Younger Dryas event – it is not part of the paper discussed below – Anthony

A group of scientists, including UC Santa Barbara’s James Kennett, professor emeritus in the Department of Earth Science, posited that a comet collision with Earth played a major role in the extinction. Their hypothesis suggests that a cosmic-impact event precipitated the Younger Dryas period of global cooling close to 12,800 years ago. This cosmic impact caused abrupt environmental stress and degradation that contributed to the extinction of most large animal species then inhabiting the Americas. According to Kennett, the catastrophic impact and the subsequent climate change also led to the disappearance of the prehistoric Clovis culture, known for its big game hunting, and to human population decline.

In a new study published this week in the Journal of Geology, Kennett and an international group of scientists have focused on the character and distribution of nanodiamonds, one type of material produced during such an extraterrestrial collision. The researchers found an abundance of these tiny diamonds distributed over 50 million square kilometers across the Northern Hemisphere at the Younger Dryas boundary (YDB). This thin, carbon-rich layer is often visible as a thin black line a few meters below the surface.

 

Kennett and investigators from 21 universities in six countries investigated nanodiamonds at 32 sites in 11 countries across North America, Europe and the Middle East. Two of the sites are just across the Santa Barbara Channel from UCSB: one at Arlington Canyon on Santa Rosa Island, the other at Daisy Cave on San Miguel Island.

“We conclusively have identified a thin layer over three continents, particularly in North America and Western Europe, that contain a rich assemblage of nanodiamonds, the production of which can be explained only by cosmic impact,” Kennett said. “We have also found YDB glassy and metallic materials formed at temperatures in excess of 2200 degrees Celsius, which could not have resulted from wildfires, volcanism or meteoritic flux, but only from cosmic impact.”

fg1_online_HIGH

The solid line defines the current known limits of the Younger Dryas Boundary field of cosmic-impact proxies, spanning 50 million square kilometers.

The team found that the YDB layer also contained larger than normal amounts of cosmic impact spherules, high-temperature melt-glass, grapelike soot clusters, charcoal, carbon spherules, osmium, platinum and other materials. But in this paper the researchers focused their multi-analytical approach exclusively on nanodiamonds, which were found in several forms, including cubic (the form of diamonds used in jewelry) and hexagonal crystals.

“Different types of diamonds are found in the YDB assemblages because they are produced as a result of large variations in temperature, pressure and oxygen levels associated with the chaos of an impact,” Kennett explained. “These are exotic conditions that came together to produce the diamonds from terrestrial carbon; the diamonds did not arrive with the incoming meteorite or comet.”

Based on multiple analytical procedures, the researchers determined that the majority of the materials in the YDB samples are nanodiamonds and not some other kinds of minerals. The analysis showed that the nanodiamonds consistently occur in the YDB layer over broad areas.

“There is no known limit to the YDB strewnfield which currently covers more than 10 percent of the planet, indicating that the YDB event was a major cosmic impact,” Kennett said. “The nanodiamond datum recognized in this study gives scientists a snapshot of a moment in time called an isochron.”

To date, scientists know of only two layers in which more than one identification of nanodiamonds has been found: the YDB 12,800 years ago and the well-known Cretaceous-Tertiary boundary 65 million years ago, which is marked by the mass extinction of the dinosaurs, ammonites and many other groups.

“The evidence we present settles the debate about the existence of abundant YDB nanodiamonds,” Kennett said. “Our hypothesis challenges some existing paradigms within several disciplines, including impact dynamics, archaeology, paleontology and paleoceanography/paleoclimatology, all affected by this relatively recent cosmic impact.”

- See more at: http://www.news.ucsb.edu/2014/014368/nanodiamonds-are-forever#sthash.Jz8DHJU3.dpuf

h/t to David Hagen.

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369 thoughts on “Younger Dryas climate event solved via nanodiamonds – it was a planetary impact event

  1. There’s always going to be arguments about. Hopefully research & time will provide a reasonably solid answer.

    The prospect of a devastating hemispheric blast so recent is a bit chilling.

    • beng –

      You haven’t heard it all yet. Google “8.2 kya event”. That is 4,600 years even MORE recent. And then if you dare, start googling different ancient people’s accounts of serious stuff going on in the sky and raining down stuff – not only in the time of man, but also in the time when the accounts are still around. Those accounts aren’t useful battling against entrenched scientific thinking, but they all seem to say that their people saw something happen.

      Recently.

      So you’ve got reason to be chilled by the idea. That’s why some people are working hard to get NASA to do some space defending – at least begin to prepare.

      • “You haven’t heard it all yet. Google “8.2 kya event””

        That’s BTW exactly the time Plato gave for the sinking of Atlantis.

      • From wikipedia:

        “The 8.2 kiloyear cooling event may have been caused by a large meltwater pulse from the final collapse of the Laurentide ice sheet of northeastern North America—most likely when the glacial lakes Ojibway and Agassiz suddenly drained into the North Atlantic Ocean.[10][11][12] The same type of action produced the Missoula floods that created the Channeled scablands of the Columbia River basin. The meltwater pulse may have affected the North Atlantic thermohaline circulation, reducing northward heat transport in the Atlantic and causing significant circum-North Atlantic cooling.”

    • YD was caused by a large comet impact. Please see

      http://faculty.nps.edu/mjjaye/docs/Esri%20Jaye%20Presentation%2015July2014%20Submerged%20Canyon%20Formation%20A%20Novel%20Explanation.pdf

      Nearly 200 years ago, geologists at The Royal Society ‘proved’ that the lands presently occupied were not inundated by a global flood. True. But that conclusion assumed that the Earth has has its present amount of water since its beginning. That is demonstrably false; presently occupied landscapes were not flooded in this event.

      I will present material similar to that found at the link, above, at the upcoming Geological Society of America conference in Vancouver. (The link is to slides from a recent Esri user conference.)

      In the words of Plato, this massive comet caused an “extraordinary inundation” – a nearly incomprehensible amount of water….

      • From what I saw in a documentary about the YD extinctions, they believe it was a comet air burst, thus no crater, sort of a mega-Tunguska Event.

      • Submerged canyons on the continental shelf were carved by now submerged rivers flowing on land when sea level was 400 feet lower during glaciations. Those deeper than that are caused by outwash floods, plus submarine earthquakes. among other terrestrial sources. No need to posit a giant comet impact.

      • While I was skeptical of a 2500 km comet containing 25% ice impacting in such a recent geological period, I found the underwater geological formations interesting. I was aware of the features down to 400 ft. depth from the last glacial sea level, but not the features below that.

        I find it interesting that they all seem to terminate near the same depth below sea level. We really don’t know anywhere near as much below the ocean surface as we do for what’s above it. I find it hard to understand how flood outflows could affect the topography to such a depth and then suddenly terminate sharply near the same depth throughout the globe.

        Is it because we don’t have detailed imagery below that depth, so we don’t see the details further down?Could it be that sea levels were once at that level? You would think that flood outflows throughout the earth wouldn’t so uniform in volume to terminate at uniform depths.

        While I haven’t read much of the literature on this, I’m aware of plate tectonics, undersea currents, flood outflows and landslides being proposed as having shaped the landscape of the seafloor. I’m sure someone well read in undersea geology could provide some knowledge or data.

      • These are interesting new ideas. BUT: Whereto has all the water gone which must have been on earth during e.g. the jurassic era when great areas of the continents were submerged under sea water???

      • If I am correct, the deepest canyon from a river draining into the ocean is the Congo. You can clearly see its canyon on Google Earth. You might add it to your list. While your thesis is interesting, it seems like a giant comet producing the volume of water you claim, would create such a huge difference in our understanding of the planet, that someone would have come up with the idea a long time ago. And I think that would have been an extinction event of nearly everything on the planet, far greater than any of the other impact extinction events.

        I could see a small comet adding to the present volume of water and a combination of ice melt and comet water raising sea levels a few hundred feet, but to have the earth as dry as you indicate in one of your pictures seems very extreme. Especially since you think it was that dry a mere 6kya.

    • Judging by the map, somewhere in or around NA there should be an impact site. I does fit nicely with the findings on the East Coast of a sterile sand layer from around that time period indicating a disaster that forced the Clovis survivors westward. There is an impact crater in the Hampton Roads/Norfolk area of VA, but it’s not a candidate, missing by some 35 million years.

  2. This has appealed to me for years.
    But I know it has been controversial for years too.

    In The Younger Dryas impact hypothesis: A requiem previous such hypotheses were found wanting.
    I quote,

    In summary, none of the original YD impact signatures have been subsequently corroborated by independent tests. Of the 12 original lines of evidence, seven have so far proven to be non-reproducible. The remaining signatures instead seem to represent either (1) non-catastrophic mechanisms, and/or (2) terrestrial rather than extraterrestrial or impact-related sources. In all of these cases, sparse but ubiquitous materials seem to have been misreported and misinterpreted as singular peaks at the onset of the YD.

    Maybe this time it’s different.

    • The research publication goes to great lengths addressing this and other criticisms. James Kennett is an accomplished, careful, and thorough research scientist.

      • I agree. If you read all of the YD impact team’s papers, the “forensics” of it all will overwhelm you. He does his homework, and so do the others.

        On the other hand, the field work is either sloppy in taking samples from the correct layer, or they take too wide of a sample, which waters down the sample in the lab – which then flattens out the spikes in the data. For several of their papers, the skeptics actually didn’t even DO any field work of their own – making those papers little more than opinion pieces. (I am not making this up.)

    • It always was different. There was a (2012??) reanalysis of the work which found that the investigators with the negative findings had apparently not found what they did not want to find – confirmation bias. Reanalysis showed the very samples that were found negative for impact markers were loaded with them. The reanalysis work had a very critical discussion of the methods employed.

      • Confirmation bias is exactly what it seems to me, too.

        James Wittke was the one with the rebuttal paper, and it basically shredded all the supposed falsifying evidence. But the skeptics were too dense to recognize that they had been body slammed.

        The thing is now even some people that thought this was a possible real thing now think that the skeptics have been successful in tearing the idea down. But basically all the YD team can do is keep testing other evidence. The world seems to simply not get it.

        They have probably more evidence for this YD event than Luis Alvarez and his supporters had for the dinosaur killer of 65 million years ago. Sites on 4 continents, more than half dozen materials normally associated with impacts (but, oh no, not in this case…). All that is needed is a crater.

        But Peter Schultz working at NASA Ames convincingly showed that a hyper velocity impact onto an ice sheet will likely NOT leave a crater underneath. The crater WAS in the ice itself – which got shattered, melted, vaporized, and blown away. And with it went the crater.

        Be aware that the ice sheet was deeper than Barringer Crater. In fact, it was about as deep as Barringer Crater is in diameter. With the ice attenuating the impact, any crater under that spot will likely be FAR differenrt from what is currently allowed as “good craters”.

    • Actually, one of Kennett’s cohorts rebutted that supposed requiem quite thoroughly. I was just re-reading some of that this week. The samples taken were done as if by amateurs – because they sampled the wrong layers. They also did not have an impact specialist on their skeptical team, though they did have a good nanodiamond guy (Tyrne Daulton – who may be heard from again in the near future.

      But as Ted Bunch communicated to a friend,

      “…not to worry, Dalton is a competent scientist and did what he could do with the materials given to him. The problem lies with [Andrew] Scott and Pinter.”

      That was back in 2010, about the “Requiem” paper.

      You also have to understand that Andrew Scott is a forest fire guy. That is what he studies. But IMHO he also wants forest fires to be important – in much the same way, that Michael Mann and Phil Jones want climatology to be important. If someone comes up with a scenario that aces forest fires, especially if it is a catastrophic hypothesis, that would mean he has to fit his forest fires in as second fiddle.

      I just looked them up the other day, and none of their “requiem” team was an archaeologist, with experience taking careful samples from the side of a pit.

      In addition, that black layer with the nanodiamonds – spread over 50 million square kms makes it kind of more than just your evreyday, garden variety brush fire.

  3. “Well, I’m happy to read it was not CO2!”

    Of course not… it’s CO2 that was responsible for the near-vertical temperature readjustment (7) though, as well as (1)… what else could explain it?

    or… the proxies of 1/2, 5/6/7 are messed up for some reason. Without those anomalies it looks like a relatively smooth rise.

    • One of the past theories was that the impact was from a radioactive comet.
      This led to the disproportionate killing off of large animals (radioactivity built up in the fat cells).

      Also, it was hypothesised that it led to the Carbon dating being messed up causing the recovery to appear like it happened overnight.

      I can’t find the paper… I think it was by Firestone.
      I remain sceptical but I do like the way “it is consistent” with the evidence

      • Firestone is the originator of the YD impact hypothesis. I heard him give the original presentation at the Clovis in the Southeast conference in 2005. The conference was hosted by an archaeologist, Al Goodyear – which made for some tiresome confusion ;-). The YD marked by an apparent radio-carbon anomaly that correlates with other environmental signatures that mark the YD. However, even if the anomaly is real, it doesn’t seriously change just how abrupt the onset and progression of the YD was.

        The radioactive comet idea really is humbug though. Radiocarbon is caused by cosmic rays and not even a comet that glowed in the dark would be that radioactive to begin with. It could not under any circumstances be radioactive enough to generate a global anomaly. Besides, objects coming in from the Oort Cloud or the Kuiper Belt have been in deep space for very long periods, possibly since before the solar system formed. That means that only very long-lived radioisotopes would have survived, and the longer-lived the isotope, the less radioactive it is. No amount of biological amplification is likely to significantly increase the radiation hazard from such isotopes to the point that large mammals would be seriously affected.

      • Even if the comet was pure plutonium, after impact the remains would be scattered over half of the globe. The total radiation at any location would be too low to kill anything.
        Regardless, as the KT impact showed, these things are most stressful on the largest animals anyway, even without postulating a radiation affect.

  4. Very interesting. Didn’t Velocovsky covern an ancient SW American Indian myth of something in the sky to the northeast prior to devastation?

      • If it was a stony comet, we might be able to find a widely distributed debris field that points back to the impact point.

      • That makes the stratigraphic reconstructions really difficult. That’s probably why they’re having such a hard time tying all the evidence together for the event, much less the location. Identifying the plume would be difficult as advancing/receding ices containing ejecta move around and then deposit after melt and runoff. I don’t envy them that task.

      • tteclod –

        No, it is not “convenient.” With expanded glaciers covering down to 40° latitude it is ENTIRELY likely that it hit on the kilometer thick ice sheet. Just as it is likely (more so) for an object to impact the ocean instead of the land. And yet, Tunguska and Chelyabinsk air burst over LAND, which is only 29% of the Earth. Amazing, isn’t it?

      • Anthony –

        I’ve got some interesting stuff on thadebris fieldt. At least A debris field. Not good enough to do anything with yet, though. But amazing and tantalyzing.

      • NielsZoo –

        There are at least three lines of evidence that point to the Great Lakes – but dating on one of them is haywire, so it isn’t quite possible to tie it to the time of the YD onset.

        I wish I was an OSL man right now…

      • Anthony – please see my comment and link, above. It was an extraordinary event – planet changing. Impact is evident at Google Earth/Maps(satellite view).

    • the 1908 Siberian Tunguska event completely flattened ~2000km^2. air bursting comet or meteorite less than 200meters in size. the YDB would have been substantially larger but it too could have been an airburst. or most heavier impacts over the ocean.

      • Even Tunguska has craters. For a global event to produce the proposed evidence, carbon nano diamonds, either the air burst would be the source of the carbon, which requires still more complex explanation of the celestial body with adequate carbon to spark the event, or there is an impact site with abundant carbon. One may reasonably estimate a center of impact, then go hunting for the crater. Even glacial concealment should be easy to consider.

      • Or a swarm of icy Tunguska-sized objects. All air-blasts w/no craters & little stone or metals. The wide area of charcoal/nano-diamond layer supports that postulate.

    • There was a paper out in 2007 which said much as the above and mentions nanodiamonds.

      Abstract – 2007
      Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling
      A carbon-rich black layer, dating to ≈12.9 ka, has been previously identified at ≈50 Clovis-age sites across North America and appears contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The in situ bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black layer but not within or above it. Causes for the extinctions, YD cooling, and termination of Clovis culture have long been controversial. In this paper, we provide evidence for an extraterrestrial (ET) impact event at ≅12.9 ka, which we hypothesize caused abrupt environmental changes that contributed to YD cooling, major ecological reorganization, broad-scale extinctions, and rapid human behavioral shifts at the end of the Clovis Period. Clovis-age sites in North American are overlain by a thin, discrete layer with varying peak abundances of (i) magnetic grains with iridium, (ii) magnetic microspherules, (iii) charcoal, (iv) soot, (v) carbon spherules, (vi) glass-like carbon containing nanodiamonds, and (vii) fullerenes with ET helium, all of which are evidence for an ET impact and associated biomass burning at ≈12.9 ka. This layer also extends throughout at least 15 Carolina Bays, which are unique, elliptical depressions, oriented to the northwest across the Atlantic Coastal Plain. We propose that one or more large, low-density ET objects exploded over northern North America, partially destabilizing the Laurentide Ice Sheet and triggering YD cooling. The shock wave, thermal pulse, and event-related environmental effects (e.g., extensive biomass burning and food limitations) contributed to end-Pleistocene megafaunal extinctions and adaptive shifts among PaleoAmericans in North America.

      http://www.pnas.org/content/104/41/16016.short

  5. Was the temperature graph part of the paper? I didn’t see it in the press release and was unable to view the whole paper.

    • I like the larger figures, and being able to address someone’s comment directly, instead of posting a reference to it waaaaay at the bottom.

  6. “Situation solved. No need to look here again. We’ve done this, now move on to something else.” It’s a nice theory, has some supporting evidence, but is it “solved?” Nothing that deals with the past through proxies is every solved, but it does present a possibility. When did scientists start saying “we solved this” anyway? I always understood that there was no solutions, just theories and possible explanations. How much better these new scientists are than they were, say 50 years ago, because whenever they take on a situation for study, they always “solve it.”

    • Tom O –

      I laughed at that. A little bit of absolutism going back and forth between their papers. One side names theirs a “Requiem” for the YD impact hypothesis. So Kennett has to come back with an in-your-face, too.

      Personally, the amount of “forensics” on this impact are quite strong and unassailable. The skeptics tried – and failed. They can only nibble around at the corners, like wolves trying to work a caribou pup out of the herd. They can’t do a thing to the core of it. Especially as there is a “suite” – several different lines of evidence, all pointing to the same thing – an impact. But if all of you think defending CO2 against warmists is a bear, try selling geloogists and astronomers on catastrophism only 170 years after they thought they’d buried The FLood forever.

      I am telling you: They will fight this until they are blue in the face. You’ll have to claw Gradualism out of their cold, dead hands. Because if this is right, then during times of catastrophe Gradualism wasn’t working anymore, and that means they’ve lost control of geological history. Even comet Shoemaker-Levy hitting Jupiter 20 good whacks in 1994 (20 years ago now!) didn’t let some of them let loose of their “comets don’t hit planets in our lifetimes” mantra.

      The Catastrophe Barrier will make the Clovis Barrier look like child’s play. ESPECIALLY if the darned thing hit on the ice sheet and there isn’t a pristine Barringer-type crater.

      • Geologists -I are one – recognize catastrophes as numerically insignificant but representationally dominant in the geologic record. The one in a thousand year flood wipes out all evidence of lesser floods AND creates a changs of such great character that it withstands the modifications of everyday processes.

        The principle that has survived the Biblical fight re The Deluge, is that the processes we see today are the processes that existed yesterday. With local necessary modifications, they are universal processes, applicable to the surface of Mars and Titan today as much as the Earth of 350 million years ago. That being said, catastophism must be viewed skeptically. Like CAGW, the idea is that the period of concern is or was “special”; normal patterns or expectations are irrevevant. This is a dangerously simple and useful concept, especially if one has a career to consider (Michael Mann), a legacy to create (b. Obama) or a fortune to create for oneself or others (Al Gore).

        Still … Comets …

        There was a lot going on 12,900 years ago. It strikes me that while disasters generally results from a connected series of small problems, including an extraterrestrial coup-de-gras is a trifle melodramatic. Ain’t saying it’s untrue, just sayin’ the story is a little CNN to warrant grabbing and running with if you don’t like the taste of crow.

  7. the KT boundary was recently revised to 66.038 ± 0.025/0.049 Mya.
    Science 8 February 2013:
    Vol. 339 no. 6120 pp. 684-687
    DOI: 10.1126/science.1230492

    • Hahahahaha –

      I freaking LOVE how they talk about things millions of years in the past as if they really bloody know it was 65 vs 66 – or 66 vs 67. Yep, the Miocene started at dawn on the 1st of January, 12.7000000000000 mya.

      When the new Carbon14 calibration curves (IntCal13) came out the YDIH was no longer at 12.9kya; it was at 12.8kya. Literally, there was Analiese van Hoesel bitching and moaning a few weeks later that the whole YDIH is full of crap because some of the layers didn’t match up with the new 12.8kya date. She said they were off by 100 years. Which James Wittke took her to task about.

      AS IF! As if they really, REALLY know it is 12.8kya now.

      But they will run around the very next day after one of these shifts like the Out-Of-Town Experts that they all claim to be, spouting exact, ROCK SOLID dates – dates that are almost as certain to change in the next 25 years as I am to take another breath in 3, 2, 1.. . . YEP, still here, folks!

      (And the FUNNIEST thing is that they pronounce REALLY tight C14 uncertainty ranges – like +/- 35 years at 13,000 years ago. I TOTALLY respect the guys doing it, but the uncertainty bars are just too tight – IMHO. I mean, they just adjusted the calibration curve by THEE TIMES THAT.)

      But then people like van Hoesel take the damned things literally. If you are off 40 years, well, to her that is not a match. (Forehead slap time…)

    • And then there are the dates on the climate reconstructions. They all have error bars for the AMPLITUDE, but they never show error bars for the time element. And that DOE make a difference – especially when homogenizing multiple proxies and many different data sets – all of which DO have error bars on the ages of the samples. It shows up on every C14 test and is there for ice cores, too. But every age of every sample, every tree, is treated as if it, too, is accurate to 7 zeros.

      What it does in homogenization of data is that if several close dates have their peaks or valleys shifted in time, that tends to flatten out the rolling averages even MORE. I’ve said before that that is ONE of the reasons Mann’s Hockey Stick has a straight shaft.

      End of rant.

  8. What’s the source of the Greenland temp graph in this article?

    Showing current temperatures almost as low as LIA :?

  9. I think the missing salient point here is how did CO2 cause the Younger Dryas and the subsequent rebound? And maybe more importantly how did CO2 maintain the subsequent stable temperatures?

    Could it be that maybe, just maybe CO2 is an inconsequential trace gas?

  10. So if it hadn’t have been for the impact event the warming period would have been another ~4,000 years, pushing the interglacial out to over 14,000 years. Great to know that with this info we really could be on the cusp of a new ice age.

    • BFL –

      The dates are 18,000ya, 12,800ya, and 11,500ya, for the end of the Last Glacial Maximum, the Younger Dryas onset, and the Younger Dryas termination. The YD only lasted 1300 years. (Some say 1,000.)

      Seeing as the vast majority of the Pleistocene – which we are still in – was ice ages, these last 11,500 years are distinctly an anomaly. If we head back into one there is SOME chance that it could “take” and we could be SOL.

    • The pattern of the past interglacial-glacial cycles is that the descent into a colder climate from the previous interglacial is, overall, a relatively gradual process, with the coldest temperatures occurring just before the next interglacial starts with a bang (that is, a rapid climb into a warmer climate). That is one of the reasons why the abrupt cooling back into icy conditions that occurred during the Younger Dryas stands out as something worth investigating. Another reason is that some specialists in human prehistory say that the rapidly deteriorating climate in areas which had enjoyed substantial population growth during the immediately preceding warm period may have led to the invention of agriculture to create a more reliable source of food.

  11. There could have been an impact at the older YDB but we don’t need it to cause whatever the Younger Dryas was. The only proxy that cleary shows large deviations is water/ice isotopes, d18O, d2H and deuterium excess in the ice cores and speleothems of the northern hemisphere. There is not any other record or proxy that supports the conclusions we have drawn from that, on the contrary, nothing fits, for instance this one: http://www.geol.lu.se/personal/seb/Geology.pdf.pdf

    But it’s essentail to note that these three isotope excursions are exactly the same during the Dansgaard Oeschger events. Consequently, if you need an extraterrestrial event to explain the Younger Dryas, you’d need to find some 25 more extraterrestrial events during the late Pleistocene to explain the other Dansgaard Oeschger events as well.

    More over many of the megafauna did not go extinct at the Younger Dryas boundary. Most species perished much earier world wide, but the iconical Woolly Mammoth thrived during the Yonger Dryas in Siberia and disappeared only well after the start of the Preboreal/Holocene. Moreover we keep witnessing the dismissal of young Mastodon carbon dates in America (and only mastodons), because that’s obviously impossible because the Mastodon died out at the Younger Dryas boundary, so that evidence must be false (what fallacy is that?)

    But also youngest date of the extinct giant deer/ Irish Elk from Siberia is 7700 radio carbon years. So why do we think that the megafauna extinction is limited to the Younger Dryas boundary?

    Comic impact, sure, why not, but you can’t blame it for all the things we see changing at the end of the Pleistocene.

    • Yes, people often point out that the Younger Dryas isn’t unique. (But don’t tell the biologists that! – THEY are the ones who made a big deal out of it, LONG before Richard Firestone et al came along with the YDIH.

      And that is supposed to shut up YD impact people. None of the others actually says squat about the Dansgaard-Oeschger events. (BTW, don’t forget the Bond events – also at 1470-1500 year intervals, for what it is worth). But I’ve tentatively suspected that the D-O events and the YD impact ARE connected. How so? Well there is something called the “8.2 kya event” (google it), and THAT is one of the Bond events. And THAT one is also suspected of being an impact – by people FAR removed from Firestone and Kennett.

      My thinking is very rudimentary, but basically it is to consider that all of the D-O events may possibly be impacts.

      As you can tell from the GISP2 graph, those are SERIOUS temperature excursions – 10 or 20 or 30 times as big as what warmists are worried about. And they all come on so damned quickly. That is not Gradualism doing that. Internal system forcings I just don’t think can do that.

      Crazy idea? Yeah, that is what everybody tells me. But ten years ago asserting ANY impacts connected with ONE D-O warming would have gotten one an invite to the straight jacket store… We now have TWO. As we here all know, correlation is not necessarily causation. But with two of them matching to Bond events and at least on of the two matching with a D-O event, it seems possible, if not probable.

    • “But it’s essentail to note that these three isotope excursions are exactly the same during the Dansgaard Oeschger events. Consequently, if you need an extraterrestrial event to explain the Younger Dryas, you’d need to find some 25 more extraterrestrial events during the late Pleistocene to explain the other Dansgaard Oeschger events as well.”

      Multiple fragments of the same object. IMO this repeated isotope deviation is evidence for impact, not against.

  12. There is much evidence that the Younger Dryas resulted from ‘sudden’ diversion of Lake Agassiz drainage (meltwater as the southern terminus of the Lauentide ice sheet) from the Mississippi valley hence the Gulf to the St Laurence hence the North Atlantic. This disrupted the thermohaline circulation until the fresh water pulse dissipated.
    It is of course possible that a cosmic impact was responsible for the diversion rather than the theorized melting of ice dams.
    It is not possible that the Younger Dryas itself was responsible for the North American megafauna extinction event at around this time. Those fauna were adapted to the ice age that was receding, and a return to those conditions per we would not have mattered. Clovis over hunting has always seemed a bit of a stretch. Too many animals, not enough hunters. This does provide a testible alternative. All the megafauna species would have disappeared from the fossil record at the time of the event. Worth researching whether that is true, for example at the La Brea tar pits or other known megafauna deposits like the recent cave (prior waterhole) discovery in Utah IIRC.
    Refreshing to read about real science rather than climate ‘science’.

  13. Oh Ja, a planetary impact.

    Extinctet mastodonts 13.000 years ago:we’ve got nanodiamonds ’50 million
    square kilometers across the
    Northern Hemisphere':what so impactet planet earth:a SUV?

    Or maybee:13.000 years ago 13.000 SUV’s impactet planet earth to produce some nanodiamonds colleterating mastotonts.

    Time sharing with them other yellow pages all over the planet earth.

    Astounded. Hans

  14. I guess the theory that the extreme warming by the Bolling Oscillation which melted so much of the continental ice sheets so quickly thus changing the thermohaline circulation causing a re-glaciation, can be put aside into the corner … for now. So much science; so many theories; when will it all become settled?

    • GOOD POINT, JimS –

      It will never be settled sa long as they keep putting patches on to SOMEHOW make the science explain what the previous idea couldn’t. Not without patches upon patches upon patches – ala MicroSoft and Windows. NOT a good model to follow.

      I call the patches “crowbars”, because they pull them out ANY time the have a falsification, and they just pull speculations out of their BUTTS and try to force the new thing to make the old idea fit the inconvenient facts. But piling speculations on top of falsified hypotheses is not science. It’s just hip-shooting and hard heads.

      The thing is, that they just need to throw OUT the falsified ideas and stop long enough to derive BETTER ideas from the bottom UP. But they identify too much with one idea, and they don’t seem to let it go. So, what e have is several falsified things still in the mix, cluttering up not only the overall, but the brains of those who stubbornly refuse to let it go.

  15. YDB is rapid but not exceptionally so. Other changes around that period were as great in magnitude and not that much slower.

    There was already a huge general cooling since the initial false start to the deglaciation.

    The end of YD was more remarkable and this time it stuck.

    CO2 levels were low enough at the glacial maximum that the increase would have had a GW effect acting as a positive feedback to whatever was driving warming. A positive feedback would also cause snap changes like YDB and YD end, it works both ways. Methane could also be a cause of GW +ve feedback.

    That kind of latching behaviour is typical of +ve feedbacks ( which have to be bounded by stronger negative f/b ).

  16. Maybe. Or, it could be the heat was simply hiding in the deep oceans, like it is doing now. Heat is sneaky that way.

  17. The temperature graph is mislabeled & misdrawn. The supposed Medieval Warm Period is actually the Sui-Tang WP, a warm interval during the Dark Ages Cold Period. The following peak is the Medieval & should be at least as high as the S-T but lower than the Roman. The stretch labeled “Little Ice Age” is the latter DACP. The real LIA comes after the Medieval Warm Period.

    http://read-think-b4-u-write.blogspot.com/2011/07/envisioning-information.html

  18. Greenland and Antarctica temperatures over the last ice age for reference. How many Younger-Dryas-type cooling events can you count here.

    • Interesting graph, Bill.

      Upto about 40ka BP the large events seems fairly well synchronised. I’d guess that phase shift before that are more likely time-scale calibration errors than bipolar disorder, though the main warming leading to deglaciation seems to have started a good 10ka earlier in SH.

    • As I mentioned earlier those alleged cooling events are the Dansgaard Oeschger events. But what you actually see is the oxygen and hydrogen isotope ratios in the ice cores, which are supposed to be proxies for temperature. However this is a logical fallacy. Affirming the Consequent. If it rains, the streets are wet. The streets are wet, hence it rains. Consequently: when it’s cold the isotopes are low. The isotopes are low, hence it was cold. Not necesarily. How about for instance arid versus moist?

      • There are plenty of paleontological records that shows that the D-O events really were temperature shifts. Or at least that animals and plants (including humans) reacted as if they were climate shifts.

    • One thing that we need to be aware of with the Greenland and Antarctic ice cores is that, being high latitude locations the cores may OR may not represent the rest of the world.

      Especially if the YD impact idea is true, then Greenland was directly downwind of the event near the Great Lakes (as I see it, anyway). And if the burning in N America was from Alberta to the Carolinas, then that was a broad front of smoke headed toward Greenland, one that could hardly miss the place.

      THAT could have had a very quick and very heavy effect on the ice in central Greenland. It would likely have been the most seriously affected place outside mainland N America.

  19. Abstract
    “A new stomatal proxy-based record of CO2 concentrations ([CO2]), based on Betula nana (dwarf birch) leaves from the Hässeldala Port sedimentary sequence in south-eastern Sweden, is presented. The record is of high chronological resolution and spans most of Greenland Interstadial 1 (GI-1a to 1c, Allerød pollen zone), Greenland Stadial 1 (GS-1, Younger Dryas pollen zone) and the very beginning of the Holocene (Preboreal pollen zone). The record clearly demonstrates that i) [CO2] were significantly higher than usually reported for the Last Termination and ii) the overall pattern of CO2 evolution through the studied time period is fairly dynamic, with significant abrupt fluctuations in [CO2] when the climate moved from interstadial to stadial state and vice versa. A new loss-on-ignition chemical record (used here as a proxy for temperature) lends independent support to the Hässeldala Port [CO2] record. The large-amplitude fluctuations around the climate change transitions may indicate unstable climates and that “tipping-point” situations were involved in Last Termination climate evolution. The scenario presented here is in contrast to [CO2] records reconstructed from air bubbles trapped in ice, which indicate lower concentrations and a gradual, linear increase of [CO2] through time. The prevalent explanation for the main climate forcer during the Last Termination being ocean circulation patterns needs to re-examined, and a larger role for atmospheric [CO2] considered.”

    http://dx.doi.org/10.1016/j.quascirev.2013.02.003

    • A drop from >400ppm to 200ppm around YDB for a drop of about 8 degrees C, that’s about 25 ppm/K getting sucked back into sinks on a multi centennial scale. Presumably mainly oceanic absorption.

      Considerably larger than figures like 8-10 ppm/K I’ve seen coming from ice cores.

      If the calibration is accurate here, it suggests that there is significant physical blurring going in ice samples.

    • Jimbo and Greg, one need to take the absolute CO2 levels of stomata data with a grain of salt. Stomata data have a much better resolution than ice core data, but they are a proxy for local CO2 levels over land, not background levels as the ice core CO2 data are.

      Local CO2 over land in general is higher than background, as a lot of organic debris decays over the year(s). In cases of abrupt climate change like the Younger Dryas was, the amount of debris can change a lot, as plant growth (and this its debris) is a lot less at colder temperatures. With as result a change in local CO2 bias. The main wind direction also can have changed and the plant growth/plant types in the main wind direction…

      Anyway, while the ice cores resolution is worse, that doesn’t change the average CO2 level of the ice core over the time of resolution, as there is no measurable diffusion in ice cores. Thus if the average of the stomata data differs from the ice cores over the period of the latter’s resolution, then the stomata average is certainly wrong.

  20. Bill Illis
    August 29, 2014 at 10:06 am

    The same D/O Cycles & Heinrich Events are evident in previous glaciations & transitions to interglacials, along with Bond Cycles within the interglacials.

    If there were an impact around the time of the YD (which I doubt on the flimsy basis of the evidence), there’s no reason to imagine that the putative event caused the YD.

    Does only Kennett’s team find support for their hypothesis? Is no one else looking?

    • None of the other rapid changes in the D-O, the Heinrich events, nor the Bond events are coincident with a black layer with the nanodiamonds and other impact markers. (The only other layer with any similarities is the K-T boundary. And we know what that one did (we think).

      The black layer shows up across N America from Alberta to the Carolinas and down to Blackwater Draw and other places, as well as in BELGIUM, and SYRIA, and in S America at the northern end of the Andes.

      Like it says above, the black layer is found in an area that spans some 50 million square kms, so it was not small. It was not even medium nor Goldilocks-sized. This was the mother of all firestorms on one of the three biggest continents. And it reached across the Atlantic AND the Mediterranean, as well as the Gulf of Mexico and Caribbean. Obviously it sent monumental amounts of soot and smoke into the air, which if it laid down a layer in Syria stronly suggests that the smoke went around the world. We are talking of a smoke cloud that was

      . That the impact “forensics” lie at the very bottom of that black layer at its interface with the next lower soils, indicates that the impact markers and the black layer occurred together. And that the black layer was added to, to make a thickness that averages about 10 cm (4″).

      50 million km^2 is basically 10% of the Earth’s surface. That is far bigger than any natural event in the known history of mankind.

  21. Greg sez: “Tom, this is basically climatology. Expect outrageous and unwarranted claims of certainty.”

    Not at all. Multiple samples of the relevant strata–no magic single tree in Yamal. No tree rings, speleothems, or bat guano strata. No ad hominem arguments. No use of the terms “robust,” “consistent with,” “rigorous,” “transparent,” “open,” or “peer reviewed.” As near as I can tell, sufficient methodology is included to permit replication. But most of all, there is no de rigueur shibboleth/ecco la fica in the closing paragraphs stating that this study confirms CO2 as the source of all global warming.

    • Yes, it seems the unwarranted uncertainty was some editorial enthusiasm at WUWT. “Younger Dryas climate event solved via nanodiamonds – it was a planetary impact event”

      Neither the press release nor the quotations from Kennet are making such claims. He always seems clear that it’s their hypothesis, not that it’s “solved”.

      My criticism was misplaced.

    • Hahaha – “As near as I can tell, sufficient methodology is included to permit replication.” Yet the skeptics of this couldn’t follow simple protocols and screwed up their effort at replication – and then they ran with their bogus results, bad-mouthing the YDB scientists.

      Am I the only one here who thinks some scientists got their degrees out of Cracker Jacks boxes?

      ROFL – I didn’t think so. :-)

  22. Jimbo
    August 29, 2014 at 10:13 am

    CO2 over 400 ppm in the late Allerød. Who knew that there were so many SUVs at the end of the Paleolithic?

    • Germany had about 10,000 CO2 samplings in the early 1900s (up into the 1930s). It didn’t affect jack. Their weather was as crappy as it often is. And lest anyone thinks “Oh, what did they know way back then?” the sampling of CO2 was well refined by about 1850. Or so I’ve read.

    • The Laurentide Ice Sheet was over 3km thick in places. Depending on the impact site, angle, energy etc. there may not have been a significant amount of crustal damage done and the melt alone could have erased it. There could have been no crustal damage done if it hit a thick area of ice. A bunch of unknowns here as the nanodiamonds would require the impactor be one of the more carbon rich meteorite types if terrestrial carbon was not the original source. Not enough data here to make that call but a missing impact site is not a falsification criteria here.

      • Peter Schultz did hyper velocity impacts experiments at NASA Ames. He got speeds of like 4 km/sec or so, and used super high-speed cameras. You are right – hitting dead center on about a 1 inch slab of ice. The loose sand underneath was still flat and basically unmarked. The ice? All OVER the place. It’s on a NOVA episode about the YD impact from about 5 years ago. One interesting aspect is that the highest velocity of ice was straight up, even with a 45° impact.

        My best info is that the thickest ice at the Last Glacial Maximum was 2 km thick at its center – near the eastern edge of Hudson Bay. I assume that it tapered to the edges. But I have no idea how high at the edges. I don’t think anyone does. But certainly less than 2 km. If the calving ice at the edge of the Antarctic is any guide, the edge was maybe 100-200 meters, and maybe tapered sharply up to 500-1000 meters. (My guess.)

        The hypothesis has the impact in the Great Lakes area. One guy – MIchael Davias – thinks that it was Saginaw Bay. And that the impactor was so big it made it THROUGH the ice sheet there and carved out the bay. With the ice being ejected along with bedrock, the rock probably ended up on the ice sheet not so far away. His idea has a lot of merit, but most scientists pretty much ignore it. After all, he’s talking about a catastrophe.

        There’s no catastrophes in Gradualism!

  23. Or maybe Mesolithic. More advanced than the Paleolithic, but still, how did they produce so much CO2? They hunted in the forests. They didn’t burn them down.

  24. why just let them collaborated ‘mastodons’ stay away and talk ’bout

    SCIENCE.

    Asking. Hans

  25. That is not the explanation because many events similar to the Younger Dryas have happened through out the historical climatic record as Don Easterbrook so clearly shows.

    If this was a one time isolated occurrence the theory they advance might of had some merit but the Younger Dryas event is not an isolated unique climatic event when one reviews the data.

    My question is why is it only in climate science that data is some how ignored?

    A much better explanation is these abrupt climate changes had to do with sea ice dynamics when the initial state of the climate was not to far from boarder line threshold values for glacial versus non glacial conditions moderated by solar variability and all the associated primary and secondary effects.

    Don Easterbrook says:
    August 21, 2014 at 8:41 am

    A big problem with computer models is that the results depend not only on what assumptions you put into the model, but also what you don’t put in.
    Some major problems with this particular model include:
    1. “The rapid climate changes known in the scientific world as Dansgaard-Oeschger events were limited to a period of time from 110,000 to 23,000 years before present. The abrupt climate changes did not take place at the extreme low sea levels, corresponding to the time of maximum glaciation 20,000 years ago, nor at high sea levels such as those prevailing today – they occurred during periods of intermediate ice volume and intermediate sea levels.”
    This statement is dead wrong–both the oxygen isotope ratios and temperature curves from the GISP2 ice core show that the most sudden warming that brought the last Ice Age to a close occurred abruptly 15,000 years ago when ice sheets were at their maximum extent and sea level was at its lowest. The ice sheets had been at their late glacial maximums for several thousand years when, out of the blue, temperatures suddenly soared 13 C (23 F) in something like 100 years, causing wholesale melting of the ice sheets. Then, just as abruptly, temperatures turned around and cooled 10 C (18 F) by 14,000 years ago. Temperatures then fluctuated up and down( but not so intensely) at intermediate levels for about 1,000 years. 12,700 years ago, temperatures took another nosedive into the Younger Dryas cold period and remained at full glacial conditions for 1,000 years. During the Younger Dryas, temperatures repeatedly changed abruptly from cool to warm (the Dansgard-Oeschger events). 11,500 years ago, another great warming spike caused temperatures to soar 12 C (21 F) in about 100 years (at one point, around 20 degrees in 40 years), then continued warming at slower rates for a total warming of 17 C (30 F) from 11,700 to 10,000 years ago. (Keep in mind that these temperatures are for Greenland, not global, but they correlate very well with temperature conditions in the rest of the world). These abrupt, multiple, intense changes (back and forth) at full glacial conditions (not ‘intermediate’) hardly sound like changes caused by gradual changes in ocean/atmospheric conditions.
    2. All of the five most significant colder temperature changes that occurred during the past 500 years (the Little Ice Age) coincided with low sunspot intervals, lower total solar irradiance, lower solar magnetic flux, and increases in the production rates of beryllium-10 and carbon-14 (isotopes created in the upper atmosphere by increase in cosmic ray flux rates). These are not mere coincidences–such good correlation is not random chance, but must be due to cause-and-effect circumstances. None of this, of course, made it into the computer model simulations.

    There are other serious problems with the methodology in this paper, but the bottom line is that (1) their initial premise of changes occurring only during ‘intermediate’ glacial conditions is dead wrong, and (2) sunspot intervals, lower total solar irradiance, lower solar magnetic flux, and increases in the production rates of beryllium-10 and carbon-14 argue strongly for other factors not included in their models. Thus, their conclusions cannot be considered

    • “This statement is dead wrong–both the oxygen isotope ratios and temperature curves from the GISP2 ice core show that the most sudden warming that brought the last Ice Age to a close occurred abruptly 15,000 years ago when ice sheets were at their maximum extent and sea level was at its lowest.”

      The standard model says that the Last Glacial maximum was between 22kya and 18kya, and that from 18kya to 12.8kya was the Allerod interstadial, when the ice sheets retreated. There is nothing about 15kya except it is in the middle of the Allerod. Nothing I’ve ever seen says the ice was at maximum at 15kya. And I’ve read scores upon scores of papers on this era. Glacial Max was at 18kya. THAT was when the big melt-off was.

      The D-O events were spaced at an average of 1470-1500 years. You say that they happened repeatedly during the 1300-year-long Younger Dryas. That does not compute.

      I agree that the abruptness and the magnitude of temperature changes are incredibly unlikely from internal forcings. For internal forcings, only when processes self-organize, like with the ENSO, can they cause changes, but the changes only amount to a few tenths of a degree C. Extrapolating 13°C or 10°C or more out of internal forcings is asking micro-forcings to do what need super macro forcings. So, yeah, you are thinking rationally there.

      But I am befuddled as to where you got your dates.

      I think there is a connection between D-O events, Bond events, and the YF onset. Some say that the D-O events prove that the YD was not an impact. But the “8.2 kya event” (google it) is considered both a Bond event and a probable impact, too (depending on who you ask). If one, maybe no connection. If TWO, then one has to think about it – what would THAT tell us?

      • Presumed hexagonal nanodiamonds aren’t, as this & other studies linked here show:

  26. This appears to be a rerun of several earlier articles making the same claim–a cosmic impact caused the Younger Dryas. Four of these have appeared on WUWT (some with comments from me) at the dates listed below: You can read the articles in the WUWT archives by searching for ‘cosmic Younger Dryas.’

    May 21, 2013 — (my comment) There are several compelling lines of evidence showing that the Younger Dryas (YD) was NOT caused by a cosmic impact or other single event. Aside from the fact that cosmic material in YD sediments doesn’t prove a cause-and-effect relationship (correlation isn’t proof of causation), the YD lasted for about 1,300 years, which is far too long for atmospheric dust not to have fallen to the ground. Even more compelling evidence is that the YD is not a simple, single climatic event–it was a series of repeated oscillations of climate each lasting several hundred years. In Scotland, Washington state, and various other places, glaciers advanced and retreated not only during the YD, but also during the preceding late Allerod cold period. The glaciers advanced and retreated as many as 8-12 times during Allerod/YD period and is thus not explainable by a single cosmic event. There were also a number of similar glacial oscillations during the preceding several thousand years. A cosmic event cannot explain the long duration (1,300 years) of the YD nor the multiple oscillations.

    June 13, 2012 — (my comment) Before jumping on the comet bandwagon, a number of dots need to be connected and some critical questions need to be addressed. For example, how could a single event, even with multiple projectiles, cause an ice age that lasted for more than 1,000 years? Surely not from atmospheric dust and if not that, then what? The Younger Dryas is not the only climatic event during the post glacial maximum period—there are also a number of others spanning the time from 14,500 radiocarbon years (about 17,500 calendar years) to 10,000 14C years (about 11,500 calendar years). These are well known, well dated, and well documented in ice cores and in the global glacial record. So the question is, how could an impact event cause both multiple warming and cooling events over a 3,000 year period? Doesn’t seem logical at all for either impact or volcanic events.
    Some other questions pertain to the evidence for the proposed cosmic event. Geologists are used to studying micro-images of rocks and looking at the two samples shown in the paper, it is obvious that both show definite flow structures that closely resemble glass flows from volcanic lava. The statement “Morphological and geochemical evidence of the melt-glass confirms that the material is not cosmic, volcanic, or of human-made origin. “The very high temperature melt-glass appears identical to that produced in known cosmic impact events such as Meteor Crater in Arizona, and the Australasian tektite field,” is very vague. What morphological and geochemical evidence? As for these specimens being identical to trinitite from atomic blasts, there is surely no flow structure in the photos shown so how can they be identical?
    The bottom line here is—a lot more dots need to be connected and these critical questions (as well as a number of others) need to be addressed before concluding that the Younger Dryas was caused by a cosmic impact.

    March 12, 2012 –(my comment) Before jumping on this bandwagon, consider the following:
    1. There may well have been a meteorite impact near the beginning of the Younger Dryas (YD), but that doesn’t prove it was the CAUSE of the YDs. It’s the same logic as saying the cause of the 1978-1998 warming coincided with rise in CO2 so the cause must be CO2. Bad logic.
    2. The YD is just the most prominent of many Dansgard-Oerscher abrupt climatic events.
    3. The YD ended just as abruptly as it began a little over 1000 years later.
    4. The YD corresponds with changes in 10Be and 14C production rates, suggesting changes in incoming radiation and pointing toward a Svensmark type cause.
    5. The problem with single event causes (e.g., volcanic eruption) is that they cannot be sustained for the length of time of the climate change. If the idea is that the cooling was caused by ejection of dust into the atmosphere, that wouldn’t last for more than 1000 years.
    6. If the YD was caused by dust in the atmosphere, it should show up in the Greenland ice cores (where even very small, annual accumulations of dust from summer ablation are well preserved). There is no such evidence of dust from an impact event throughout any of the well preserved YD ice core record.
    7. The list goes on and on–too many to include them all here. Perhaps a longer response later. The bottom line is that a single event, meteorite impact event doesn’t prove the origin of the YD.

    I also wrote two articles explaining the issues (posted on WUWT).

    http://wattsupwiththat.com/2013/06/02/multiple-intense-abrupt-late-pleisitocene-warming-and-cooling-implications-for-understanding-the-cause-of-global-climate-change/

    http://wattsupwiththat.com/2012/06/19/the-intriguing-problem-of-the-younger-dryaswhat-does-it-mean-and-what-caused-it/

    The issues are clear cut and spelled out in these comments and articles. In a nutshell, the Younger Dryas includes so many very sudden, intense climate changes over a period of several thousand years that it couldn’t be related to a single cosmic event. Even if there was a cosmic event as the authors postulate, it certainly didn’t cause the Younger Dryas.

      • Dr. Easterbrook,
        You are trying to to take a scalpel to a gun fight! Trying to replace the “CO2″ meme with the knowledge of “it’s the sun stupid” will take many more years. Remember the movies where the witch doctor points to an eclipse of the sun and everyone starts to dance and sing to the gods? IMHO this is currently how the “deniers” are being depicted.

        My prediction is that it will take another 15 more years for the “climate science” departments and many others to be condensed and or elimated. This will only happen after the “old” scientists die or retire and when the newer scientists can publish without the obligatory bow to CO2. “It’s the sun stupid” is threatening to take food off of too many people’s plates! Follow the money!

    • I agree. It appears to this old geologist that two unrelated events are being conflated. The extinction event is much more likely due to impact of extraterrestrial material with the atmosphere – perhaps the Carolina Bays and other apparently time-equivalent impacts are related – think about 500+ concurrent Chelyabinsk events – and the resulting disruption in the atmosphere and on the ground below.

      The climate shift was quite probably associated with other completely independent influences. That they appear at about the same time is purely coincidence.

    • Don Easterbrook, after each sizable cosmic impact on Earth always follow 3 phases: 1. A sharp downdip of temps, followed by 2. a temp rebound to a level substantially HIGHER than at the cosmic impact date and finally, the last phase, 3,. a temp regress back to the lower temp level of the impact date — this mechanics produces a Z-shaped or high-voltage sign e.g. in the Greenland GISP2 temp time series. More on relation on effects of cosmic impacts and Z-type temp evolution at

      http://www.knowledgeminer.eu/climate_papers.html,

      there is no point of wild speculating around with volcanoes, dust, time span without first doing some reading on the empirical relation and the effects of a cosmic impact on climate change…regards JS

    • Don –
      “the preceding late Allerod cold period. ” Actually, the Allerod was not a cold period. It was the interstadial, when temps reached close to today’s.

      NO, they have not addressed the question of the length of the YD. Yes, of course 1300 years is too long to have dust up in the air. By a factor of 100 or more. The YD researchers have been bogged down dealing with the carping of their skeptics on the impact materials – which are very real. As this paper shows. Saying that materials that MUST be heated above 2200C are not indicative of an impact (and not possible with any Earth processes on the surface), and all the different ones are all spiking right there – what does it take for you to even look at their data? It ain’t ONE material that convinces – it is the suite of materials. Right now the focus is on making the case for the impact materials. The other questions can’t be dealt with just yet. It’s not an excuse; it’s reality.

      The black layer being on 3 continents and with some evidence of it in northern S America, too, indicates a natural event larger than any in known human history. With essentially the same suite of markers in Syria and Belgium, something happened that was big. Super big.

      I myself think that the single biggest question is that 1300 years – and then the even more abrupt RISE in temps.

      At the same time, I do not take Greenland ice now or 13,000 years ago as a valid proxy for the state of the climate. The D-O events may simply be an artifact of the location. The GISP2 core suggests very big changes in temps, over seemingly impossible time periods. Nothing within the climate can do changes that big. They are all micro-forcings, with no capacity to do much more than a few tenths of a degree. Either something (perhaps at multiple times?) from outside the system intruded or we should consider that we are getting a false picture from the ice cores. At least as it pertains to global climate.

      At the same time, it was not Firestone and the other YDIH researchers who first made a big hoopla about the YD. It was biologists and climate guys. And they have been at it for DECADES, with no resolution on the horizon. Firestone and all of them can’t help it if their C14 numbers kept coming back with 12.9 kya written all over them. If the dates came back with 37 kya on them some other scenario would have had to be dealt with.

      And when they found mammoth bones immediately UNDER the black layer – with the black layer draped ON the surface of the bones and staining them – what were they to think? No connection at all? Not even. There they are, at 12.9 kya (now 12.8 with IntCal13), black layer, mammoth bones, spikes in nanodiamonds, spikes in several other markers for impacts. ONE marker is one thing. A suite of them is a whole other ballgame.

      The 1300 year conundrum will still be out there. First things first.

  27. Can someone please vacuum off the frozen mastodon, the frozen one with food in the stomach, and find the dust and micro diamond.

  28. Based upon what I have learned about extinction of mammoths and other mega fauna, I find the comet hypothesis woefully inadequate. It is hardly settled science at this point.

    • Not a comet in either case. A meteor contributed to demise on the non-avian dinosaurs. The meteor hypothesis for the demise of the Pleistocene megafauna is thin at best. The same & similar species also went extinct outside the region allegedly affected by an ET impact.

  29. Megafauna extinctions in North America do not correspond closely with the YD, although C14 & calendar year comparisons make for difficulty. In any case, different species & populations went extinct at different times, as nearly as evidence can be resolved.

    For instance, island populations of ground sloths survived for thousands of years longer than on the continent.

    • Actually, at Blackwater Draw there were mammoth bones immediately under the black layer – which has been dated to 12.8 ya on many occasions. Not only was the mammoth there, but the black layer lay over and conformed to the bone. Not only that, but the black material was in intimate contact with the bone and stained the bone.

      Outside the pygmy mammoths, no mammoth in the world dates past that 12.8 kya.

      C14 vs calendar dating is a simple matter of looking the carbon14 (calendar) date on the IntCal13 graphs. Or, if you are lazy, there is software to do the comparing. It’s not difficult at all.

      As to the claims of different times, people say that. So far in all my reading of papers on that, no one has shown any that lived past 12.8 kya. That mammoths died earlier? If the LIVED earlier, then of course they DIED earlier.

      Pleas can you point me to the ground sloths? I’d be quite interested.

  30. 1.) How is a North American event supposed to have caused South American extinctions but not, apparently, Eurasian or African?

    2. How is an event which caused a blip in temperature indistinguishable from a great many others supposed to have caused extinctions even in areas in NA which were west of the supposed fallout area? (But not outside of NA.)

    3.) Why does UofC@SB think ‘science is magic’/’science is settled’ reporting appeals to the public? “..until recently, could only speculate as to why.”

    • 1.) and 2.) both good and very valid questions. And ones that the researchers are well aware of. I’ve been on this for about 7 years or so, and I can tell you that the researchers on it are bogged down just trying to get people to accept their “forensic” results. There is a small group of hacks that the researchers think they have to please, so they are spending all their time on that. They do not have unlimited manpower. Give it time.

      There are considerably more PRO papers and researchers than there are CONs. Some of them came out of the blue. Like last year some researchers at Harvard and Princeton found supporting evidence.

      If you go into the voluminous lab tests in the Appendices to the different papers, you will see that this is serious stuff, very real. Some of the materials are impossible to create without the super-high pressure and temps in a hyper-velocity impact. So, if not an impact, then what? If it looks like a duck, quacks like a duck, and has duck feet. . .

      There are multiple lines of evidence.

  31. At least in those days they had climate change you could believe in. I wonder if they too had high priest predicting the end of the world. When exactly did they have their tipping point.

    • I’ll tell you what:

      If you ever get around to reading the accounts of some of the indigenous peoples, it is not hard to start thinking that something actually DID come out of the sky, with a tail like a dragon, blah blah blah and killed a whole lot of people and shook the earth and caused all kinds of havoc.

    • Evidence still suggests that we did indeed have a big impact among the naive megafauna of the New World.

    • Hahaha –

      Yeah, the idea of a few thousand guys on foot scouring the entire N American continent – in 200 years – and were able to FIND all of them, much less kill them. That soudnds plausible to me.

      Especially when they were killing something bigger than elephants and curing and hauling the 5 tons of meat back – still on foot.

      And THEN consider this:

      There are only 14 kill sites on the whole continent, and those are where? Basically, like 95% of the Clovis sites are in the SE of the USA. (A site comprises ANY Clovis point, even one – even a broken one.) Google “clovis sites map” THERE ARE A LOT OF SITES. And hardly ANY out west. Where the mammoth kill sites are.

      But how many kill sites are in the SE of the USA?

      None.

      Their families were back east, and they were out in Texas and NM and Arizona, killing mammoths and butchering them. To take the food WHERE? Back to Alabama? From New Mexico?

      • And BTW, they came up with that Clovis, Extinctor of Mammoths thing when they assumed that the only hunting Clovis man did was for Mammoths.

        And you know what they are only now beginning to find out? They hunted rabbits and deer and raccoons and foxes – stuff you can sling over your shoulder and take back to camp to cook for dinner tonight – just like all hunting societies did.

        So, with 95% of Clovis in the SE and lots of deer and such to hunt there, what were they doing out west, 1500 mile away?

  32. Global effects of comet impacts and volcanoes (which can be triggered by comet impacts) has been a topic I’ve followed with great interest. I’m convinced they are effecting things on this planet much more so than we realize. Not only effecting the weather, but civilizations.

    The last major impact coincides with the time of the Pleistocene–Holocene, and the Holocene extinction event. It’s the 6th great extension event on the planet.

    Wooly Mammoths, Saber Tooth Tigers, Giant Sloths, and so many other animals, were pushed into extinction. Or, in the case of the early human inhabitants, were nearly made extinct. Humans then re-populated the N America with a second wave of migration. That’s the one you were probably told about in your high school history books, but humans were here for much longer.

    Also coinciding with the time of the impact was the end of the last ice age, when much of N America was covered by a glacier. As the ice melted it created a huge fresh water lake covering cover of Manitoba, northwestern Ontario, northern Minnesota, eastern North Dakota, and Saskatchewan. It made all the “great” lakes added together seem like ponds in comparison. It was approximately the size of the Black Sea, about 170,000 sq miles.

    As the lake filled, it eventually broke through draining through the Mackenzie River and then into the Arctic Ocean. That’s a MASSIVE amount of fresh water pouring into the salt water in the Arctic. So much so it would be a likely source of flood myths. This water was even flowing south through the Mississippi River.

    This must have altered the global climate, and it would have altered the Thermohaline Circulation (aka Atlantic Conveyor Belt). Then there was another great draining around 8,200 years ago (or 6200 BCE), after more ice had melted. This last great melt happens to coincide with the the 8,200 yr climate event. Evidence for this event can be found in Greenland ice cores.

    These melts were so large they would have increased global sea levels (~6ft).

    The disruption to the Thermohaline Circulation would have likely triggered global cooling. Possibly by as much as 10 deg F. The total duration of the cooling was ~150 years, with sudden cold periods of ~60 years. Even more curious, global CO2 levels dropped ~25ppm.

    Such a dramatic impact on the Atlantic’s thermohaline circulation would likely cause a shift in the latitude of the jet stream. This is like the current Polar Vortext, which is when the jet stream has shifted south and pushes the colder air from the Arctic over warmer lands. It would also effect global precipitation. Some ares become much wetter, while others become much drier.

    Africa went through ~500 years of drought. The event likely given Mesopotamia the support for their irrigation, which gave rise to agriculture and the surprise of food. This in turn gave rise to the advancements of civilization. But then very suddenly (~100 years) the global climate seems to have corrected itself, and ended this unique weather phenomena.

    The Burckle Crater may be the result of comet impact around 2900BCE. It’s about 18 miles in diameter, and it’s under the Indian Ocean at 12,500 feet below sea level. If this does turn out to be an impact crater, it would have caused a mega-tsunami of biblical proportion (e.g. mythical flood event that would have wiped out civilizations along the coasts).

    It’s another example of how natural causes come along every few thousand year and dramatically change the global climate. There are a number of comet impacts that has effected civilization. I wish the historians were talking with the paleo-climatologists, and comparing their timelines.

    The end of the Medieval Warm Period (MWP) created the Great Famine of 1315. The rise to the population explosion as a result of the good climate during MWP. It all came to an abrupt end with the shift to cold weather. The end of the MWP saw millions died after as crops failed for several years. The following few decades were some of the worst weather on record.

    Along with the cooler temperatures were heavy rains throughout Europe. So much so crops failed and people starved. Without the hay to feed livestock, the animals also died. People were more concerned with survival than enlightenment. It wasn’t until the global climate recovered that we enter the Renaissance.

    Meat preservation during this period became difficult and unaffordable since it was based on the use of salt, which was produced by evaporation but became nearly impossible due to high humidity.

    Natural forces effected civilization was the Dark Ages. It was actually “dark.” There was hundreds of years of vocalic eruptions triggering global cooling. Hekla blew its top in 1300 and continued to spew its guts for one full year! It was called the “Gateway of Hell” by the Europeans.

    There’s a scale for measuring eruptions, the Volcanic Explosivity Index (VEI). When you get a VEI 4 you’re at the point where it will effect climate. Not only was Hekla a VEI 4, but it was spewing its guts throughout the Dark Ages. That’s just one volcano. Then in 1362 Iceland’s another monster blows it’s top and is bigger than the famous Mount Vesuvius that buried Pompeii. You can find a history of volcano eruptions throughout the Dark Ages.

    The destruction of the very advanced Minoan civilization was caused by the Santorini eruption in 1645 BC. This monster was a mega-eruption at VEI 7. It was an island, and when it blew its top the island was gone. This left a crater below sea level, causing the ocean to rush into the gaping hole causing an even bigger explosion. All that water (~20 TRILLION gallons) was instantly vaporized, and thrown high into the atmosphere. Some of it froze and remained floating around the world as tiny particles of ice (mirrors). This reflected solar radiation for several years, causing an even longer and colder volcanic winter.

    The Santorini eruption was seen in ancient Egypt. They even had a tsunami wave reach their coast. That eruption also triggered the expected famine and diseases. In fact, the story of the Exodus and the ten plagues of Egypt can be explained as a result of a volcano.

    The Huaynaputina eruption in 1600 triggered a couple years of volcanic winter, causing the Russian famine of 1601-1603 when more than half a million people died.

    I’m amazed by the irony of how Briffa’s work on tree ring and climate is so focused on CO2 levels and temperatures. That same data can be used to show the effect of volcanoes, which should be correlated to events in civilization.

    • The warm & cold centennial-scale climatic cycles observed during the Holocene & prior interglacials & glacials are not caused by volcanic eruptions.

      Hekla for example was more active during the Medieval Warm Period (c. AD 900-1400) than it was during the Little Ice Age (c. 1400-1860) or so far in the Modern Warm Period (c. 1860 to present). Here are its VEI 3, 4 & 5 eruptions for each cycle. The year given is for when the activity began, but six lasted more than one year or included back to back annual eruptions.

      http://www.volcano.si.edu/list_volcano_holocene.cfm

      Medieval WP Eruptions of Hekla (~500 years):

      1104: 5
      1158: 4
      1206: 3
      1300: 4
      1341: 3
      1389: 3

      Little Ice Age (~460 years):

      1510: 4
      1597: 3
      1636: 3
      1766: 4
      1845: 4

      Modern WP (~154 years to date):

      1947: 4
      1970: 3
      1980: 3
      1991: 3 (same year as Pinatubo)
      2000: 3

      If there be any correlation at all, it’s that great activity warms rather than cools the climate, which is indeed what researchers have generally concluded, despite short-term cooling of weather for a year or two, possibly a few years for the very biggest, tropical eruptions.

      • The warm & cold centennial-scale climatic cycles observed during the Holocene & prior interglacials & glacials are not caused by volcanic eruptions.

        Just to be clear, I’m not claiming volcanoes are driving climate. I was talking about how comets and volcanoes can disrupt civilizations. They also effect weather, in a number of ways.

        As for the large time scale changes in climate, my understanding is that it’s driven by the Milankovitch cycles.

    • Jim –

      Good stuff. Keep at it.

      But dump the Lake Agassiz thing. It didn’t happen. The ice was still too far south at the Holocene start. The ice was not retreated enough in time to do any of that. Wallace Broeker was the guy who came up with that idea, and he admitted a few years ago that he had to abandon the idea.

      But he didn’t come out very very vocal admitting his mistake, and so many people don’t even know that he dumped the idea.

      OTHERS, though, think that an outflow down the Mackenzie River and exiting into the Arctic Ocean up near Alaska is just as good. But that is like 4,000 miles and at the other far corner of Canada. Even f fresh water went that way, it had to make it past the Canadian Archipelago and Greenland in order to end up east of Iceland and screwing with the Gulf Stream.

      Anyway, that is a dead horse.

  33. The historical temperature graph at top, if accurate, shows the Younger Dryas could not be an impact event as the temperate drop was in stages over hundreds of years — an impact event would be abrupt. A sensible cause would be that the Bering Strait opened up giving the Pacific access to the totally frozen Arctic ocean, and when an undersea current connected the Pacific and the Atlantic underneath the miles-thick Arctic ice cap, then the oceans were inundated with new cold water which caused the cooling of the Younger Dryas. Thus the stages of the Younger Dryas shows the progress of that progressive melting out of the Arctic ice.

    As for large animals, it astounds me how scientists are still looking for fairy tales to explain the mass deaths, when it was obviously human hunting. Where people went, the large animals were hunted to extinction — this is not hard. Of course the Clovis hunting culture and the large animals vanished at the same time. Here in NZ there is the same pattern: the Maori arrived c1100 and their first culture is known as the “moa hunter” culture as they hunted the native giant birds. About 300 years later the moa went extinct and the “moa hunter” culture ended. This is not hard.

    By the way, the historical temperature graph at top mis-identified the MWP, it’s the next little hill to the right.

    • Don’t be too hasty. That “temperature” graph is not measured temperature. It is INFERRED. And not just the temps, but the timing also, all of it is VERY low resolution. Ice cores CANNOT DO high resolution – i.e., 200 years.

      So don’t think that those curves are real. Even the data points – the line you see? It can be doing all sorts of things in between the data points as they’ve inferred from the 18O proxies. Most of these have straight lines and when it drops really fast, and the next point is 200 years later – did it drop even MORE straight down from the upper point? Or did it go flat first an THEN drop straight down? The LINE is a guess, when you start looking at short time periods. When you zoom in. YOU can zoom in, but the data can’t.

      As to the humans hunting EVERY single mammoth on the ENTIRE continent –

      (Most people don’t know most of this…)
      1. 95% of Clovis people lived in the SE USA (based on the number of Clovis sites, which are QUITE numerous)
      2. There are ZERO mammoth kill sites in the SE USA.
      3. Wouldn’t you think that they would have killed afew mammoths near where they lived?
      4. Why would they go out to Arizona and Montana from Georgia or Alabama, just to kill a 5-ton animal – to carry 3 tons home? ON FOOT?
      5. There are at last count FOURTEEN Clovis kill sites.
      6. N America is like 98 MILLION square miles.
      7. Clovis entire history in the world only lasted about 250 years.
      8. Lifespans back then were about 25 years.
      9. The Overkill Hypothesis was thought of when it was assumed that Clovis ONLY hunted and ate Mammoths and other megafauna.
      10. Anthropologists only now are discovering that Clovis hunted and ate rabbits and deer and elk and bear and foxes and raccoons, etc. They ARE revisiting their Mammoth extinction machine understanding of Clovis.
      11. Clovis points did NOT come from over the land bridge at Beringia. The tool technology in NE Siberia is another tech altogether.
      12. The only close relative to the CLovis point is the Solutrean point from Spain and France. As long as the Clovis Barrier existed (saying that no one was in the Americas before Clovis at 13,300 years ago) there was a 5,000 year gap between Solutrean points and humans in the New World. Since 1997, when the Clovis barrier was broken, human evidence in the New World has been pushed back to more than 20,000 years – about a 2,000 years overlap with Solutrean points – plenty of time for Clovis to develop from Solutrean. So now there are researchers who assert that the Solutrean point came with people from Europe, and the people came much earlier. And if they did, they would have most naturally come to the SE USA – right where we find 95% of the Clovis sites.

      So, don’t be so certain. Evidence is coming up all the time that keeps changing our understanding of the settlement of the New World and about Clovis.

      • Verbiage is no substitute for logic. Consider the Petri dish if you think the North American continent is “vast” — no more vast than is the Petri dish to a single yeast bacterium which fills it up in a day. As I said, “this is not hard” — full stop.

      • “Lifespans back then were about 25 years.”

        That’s an average (and a very low estimate I find dubious, to begin with: most papers give 34 or 35 average) between a big peak at the range 0-5 and a rising tail beyond the age of 60. Reconstructed modal age from primitive hunter-gatherer is 62 to 64 years old. 80-years-old were merely uncommon.

    • Similar story in Australia:
      “New evidence based on accurate optically stimulated luminescence and uranium-thorium dating of megafaunal remains suggests that humans were the ultimate cause of the extinction of megafauna in Australia. The dates derived show that all forms of megafauna on the Australian mainland became extinct in the same rapid timeframe — approximately 46,000 years ago …” (Wiki).

  34. Major upsets to the world like this one would not be a comet. More likely a glancing blow from something bigger and a shower of accompanying debris. There was a period where humans almost became extinct, being adaptable as we are the event must have been severe and affected the entire globe.

    • Sure. And comet Shoemaker-Levy 9 didn’t hit Jupiter in 1994. Comets never hit planets. Everybody knows that.
      Except Jupiter has been hit by two other comets.

      Something bigger? They can’t even find the crater for THIS one.

      Actually, I think it is MUCH more likely to be a big, solid meteor. But one as big as the biggest piece of Shoemaker-Levy would do us in. How big was that? 1.3 km. And that WAS a comet.

      It’s plume was bigger than Earth.

      And there were THREE of them of 1 km or bigger. Three would do us in.

      • For the large impact area with no crater, it could have been the near passing of one of the gas planets of an inbound large loose comet that was gravitationally fragmented into hundreds of thousands of smaller pieces, that impacted the earth over several hours upon arrival, starting in the SW USA/Mexico area moving North East as the earth revolved and the last of it swept into Europe.
        The resulting shock wave moved as a front with the central bulk of the material striking the Glacial Ice sheets, blasting most of the polar Ice into the Siberian area of frozen standing mammoths and mastodons covering them instantly with meters of snow and ice chunks. There is some research that shows the southern trajectory ice chunks so liberated fell in a swath of the South Eastern USA and formed the Carolina Bays as they splashed impacted, along the southern rim of the secondary ejecta pattern.

      • “For the large impact area with no crater, it could have been the near passing of one of the gas planets of an inbound large loose comet that was gravitationally fragmented into hundreds of thousands of smaller pieces, that impacted the earth over several hours upon arrival, starting in the SW USA/Mexico area moving North East as the earth revolved and the last of it swept into Europe.
        The resulting shock wave moved as a front with the central bulk of the material striking the Glacial Ice sheets, blasting most of the polar Ice into the Siberian area of frozen standing mammoths and mastodons covering them instantly with meters of snow and ice chunks. There is some research that shows the southern trajectory ice chunks so liberated fell in a swath of the South Eastern USA and formed the Carolina Bays as they splashed impacted, along the southern rim of the secondary ejecta pattern.”

        At this time no one knows if the proposed YD impact was perhaps a fragmented body with multiple impacts. Some people think so. If so, it is far too early for figuring out what multiple impacts would have done or where. It is probably premature to go in that direction, but who knows?

        One of the important peripheral questions DOES have to be, “If the impact was in N America, then that could explain the extinctions in N America, but how did that make mammoths in extreme northern Siberia also go extinct?” If this all goes that far, then your conjecture is going to be one of many to answer that question.

        As to the Carolina bays, yes, because of the non-hyper-velocity nature of the bays, some other process must have caused them than a full-speed body from space.

        For those that don’t know, those are nearly 44,000 elliptical depressions, mostly in the SE USA, in an arc from FL to NJ. They are aligned in each region – north to south – and the alignment changes gradually, in such a way that they all seem to point to the centroid of the arc that they seem to form. They have been known about since about 1930, and NONE of the posited explanations so far has worked. Despite it failing as an explanation, the people who advocate winds claim to have the answer. This explanation has been ruled out as a FAIL on more than one occasion, but it doesn’t stop the “aeolian” people from claiming they have the answer.

        As to secondary impact – of ejected materials landing far from the initial impact site – that IS being studied by some people, with me on the periphery of that. I can say that I favor that, but it is a LONG way from being accepted. (When I use the term “arc” above, I DO mean it, too. It is, in fact, a very tight arc – amazingly. Both the alignments and this arc show a centroid near the Wisconsin border with Illinois. This dual alignment is something that the aeolian folks couldn’t explain, even if they wanted to. They would only be able to invoke “coincidence” to explain it.) The aeolian people claim the high ground, but when I look at their work, I see many assumptions that are not sustainable.

        Another thing about the Carolina bays is the difficulty in getting a date for them. Depending on where the dating samples came from, the dates range from about 11,000 to about 300,000. One guy I know says it is either 40,000 or 130,000. And this is in the times when we have REALLY GOOD dating techniques! C14 may or may not be useful, because it is only good up to about 55,000 years ago. But there is precious little organic material to work with. The sampling issue comes from the assortment of sampling locations. Almost all are just outside of the bay rims, but some ore ON the rims, and some under.

        The bays have one more interesting feature. There is a layer of very pure quartz sand, draped over the bays. It tends to be about 1 meter thick, at the bays, but in the surrounding region the sand layer is up to about 10 meters thick. The sand is so pure that it can be scooped straight out and made into very good glass – even without any further processing. It is thinkc enough in other places that fully grown, fallen, bald cypresses are found deep inside the layer. And these cypresses are hoisted out and made into furniture – even though they are perhaps 40,000 years old. The quartz sand is perfect for OSL dating, but they keep getting WAY different ages.

        So, for now, the Carolina bays are, IMHO, undated. They MAY be connected to the proposed YD impactor, but those around me are all skeptical of that. I don’t know, myself. Obviously, if they go back to 40,000 years, there is no connection.

  35. I read this book maybe 20, 25 years ago, after finding it browsing in the local library, and for ME, the “secret” of Atlantis was pretty much a resolved question from that point forward… Not that Muck necessarily had all his science right (especially considering he wrote this book at a time not even the Big Bang theory had been “proven” over the Steady State theory of the universe), but that I DO believe he proved a small comet or meteorite hit in North America and probably bouncing into the Atlantic 10-12,000 years ago.

    I JUST finished watching a new, 2-hour show on the History Channel about the origins of Clovis Man on North America and the “curiosity” about why and how both Clovis AND 80% of all large land mammals on North America suddenly VANISHED about 13,000 years ago, and then about 2,000 years later, they start seeing human artifacts again… Ice cor samples revealed that just as the ice age was retreating, allowing humans to setle North America, a second, shorter “ice age” of about 1,000 years QUICKLY descended upon the planet, and Alan West of the University of Michigan has discovered microscopic metalic balls and “microdiamonds” at the level at that EXACT point in the geologic layer ALL OVER NORTH AMERICA that indicate the distribution of materials from a comet or meteorite — materials that RARELY exist anywhere but in OUTER SPACE.

    Of course he apparently never heard of Otto Muck, and he thinks his idea is ALL NEW and that said meteorite hit the ice mass in Canada, and he could be right — or they BOTH could be wrong…

  36. It seems highly unlikely that the stories from antiquity were simply made up. more likely there were catastrophic events over large areas; and that we simply assume all were local events. how long ago they happened, passed from generation to generation, none can say with certainty. however, they were large enough to remain with us many generations later.

    two events stand out. the great flood and the day/night that took too long. Perhaps we underestimate how long ago these events happened. 13,000 years is what, 650 generations?

    • “In the section “A Collective Amnesia” of Worlds in Collision, published in 1950, Velikovsky outlined his principal psychological thesis. His theory of collective amnesia explains the inability of people to look at the overwhelming evidence of global catastrophes — from all parts of the world — that is unequivocally there, and the unwillingness to see the implications of that evidence. Velikovsky put this as follows in Worlds in Collision:

      The memory of the cataclysms was erased, not because of lack of written traditions, but because of some characteristic process that later caused entire nations, together with their literate men, to read into these traditions allegories or metaphors where actually cosmic disturbances were clearly described.”

      All of these attempts to explain away impacts stem from the collective trauma buried in our racial memories. We need to feel we are important and have some control over our lives and the world, however the delusion of human control is snuffed out by the uncaring destruction that is unleashed on the world by what have been repeated impacts of celestial bodies. So, they didn’t happen, and we live in a very slowly changing world where we are important and powerful beings.
      It could also be argued that the irrational fixation on anthropogenic climate change is the other side of this collective mental illness. We need to feel important and find it almost impossible to believe we are not, so, anthropogenic climate change that can destroy the planet.

      • ““In the section “A Collective Amnesia” of Worlds in Collision, published in 1950, Velikovsky outlined his principal psychological thesis. His theory of collective amnesia explains the inability of people to look at the overwhelming evidence of global catastrophes — from all parts of the world — that is unequivocally there, and the unwillingness to see the implications of that evidence. Velikovsky put this as follows in Worlds in Collision:

        The memory of the cataclysms was erased, not because of lack of written traditions, but because of some characteristic process that later caused entire nations, together with their literate men, to read into these traditions allegories or metaphors where actually cosmic disturbances were clearly described.”

        All of these attempts to explain away impacts stem from the collective trauma buried in our racial memories. We need to feel we are important and have some control over our lives and the world, however the delusion of human control is snuffed out by the uncaring destruction that is unleashed on the world by what have been repeated impacts of celestial bodies. So, they didn’t happen, and we live in a very slowly changing world where we are important and powerful beings.
        It could also be argued that the irrational fixation on anthropogenic climate change is the other side of this collective mental illness. We need to feel important and find it almost impossible to believe we are not, so, anthropogenic climate change that can destroy the planet.”

        A good observation. And true, about the written accounts, though many were pre-writing and were kept as oral traditions until writing came into vogue. Those ancient accounts WERE very clearly describing big, bright, burning objects descending to the earth and causing havoc – quakes, huge explosion sounds, rains of fire, inundations, many or most of the people being killed.

        The amnesia was willful on the parts of the first western readers of/listener to those accounts – insisting that the ancient peoples were all illiterates with minds like infants, and isn’t it a shame how they make things up?

        Well, if it was one account out there in isolation, no problem – it is someone’s fantasy. When the same kinds of accounts show up in hundreds of ancient societies, scientists need to wake up and smell the commonality in the accounts.

        Yes, the amnesia is there, – and it occurred in the last two centuries or so. And it has gotten in the way of us learning our own history, by replacing it with the silly transliterations of the early archaeologists.

        Velikovsky did a decent job of accumulating these accounts, as well as pointing to things like the mammoths in Siberia, the erratic boulders, the bone caves – even if his astronomy was way off course. Like early archaeologists trying to prove the literal truth of the history in the Bible, Velikovsky seemed to be trying to do the same thing, about the Exodus and manna, etc. And all he did was embarrass himself – though Harlow Shapley of Harvard was an asshole in the way he dealt with it.

  37. when it was obviously human hunting.
    =========================
    hunting does not explain the sudden demise of Siberian mammoths 12000 years ago, with the rapid freezing of many specimens.

  38. Proceedings of the National Academy of Sciences PNAS
    vol. 106 no. 43, Todd A. Surovell et al, 18155–18158
    October, 2009

    An independent evaluation of the Younger Dryas extraterrestrial impact hypothesis

    ABSTRACT

    Based on elevated concentrations of a set of “impact markers” at the onset of the Younger Dryas stadial from sedimentary contexts across North America, Firestone, Kennett, West, and others have argued that 12.9 ka the Earth experienced an impact by an extraterrestrial body, an event that had devastating ecological consequences for humans, plants, and animals in the New World [Firestone RB, et al. (2007) Proc. Natl. Acad. Sci. USA 104:16016–16021]. Herein, we report the results of an independent analysis of magnetic minerals and microspherules from seven sites of similar age, including two examined by Firestone et al. We were unable to reproduce any results of the Firestone et al. study and find no support for Younger Dryas extraterrestrial impact.

    Use the Data Supplement page link beneath the PNAS abstract for a PDF download providing lab procedures, sample sites details, and data table.

    • Ted –

      Yes. This is the Surovell paper in which he failed to follow the proper methodology when taking samples, so he screwed the pooch. This work was well rebutted. Surovell hasn’t tried gathering samples again, from all appearances.

      For some reason the YDB skeptics still haven’t enlisted an archaeologist who know how to take proper samples from a dig.

      • Steve Garcia,

        Are there sources for these objections to the Surovell et al work & qualifications?

      • I have one somewhere from 2009 or 2010, but am finding it hard to locate. In its stead, I will provide 3 or 4 others.

        Blog post with the main thing being the LeCompte paper just below here…

        http://cosmictusk.com/wittke_pnas_younger_dryas_clovis_comet/

        The first one LeCompte et al 2013 Evidence for deposition of 10 million tonnes of impactspherules across four continents 12,800 y ago has this:

        Whereas most independent studies concluded that the YDB spherules formed during a high-temperature cosmic impact event, one study by Surovell et al. (10) was unable to find any YDB spherule peaks at seven sites. However, LeCompte et al.(13) repeated the analyses at three of those sites and verified the previous observations (1), concluding that the inability of Surovell et al. (10) to find YDB spherule peaks resulted from not adhering to the prescribed extraction protocol (1, 7). For example, Surovell et al. did not conduct any analyses using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), a necessary procedure clearly specified by Firestone et al. (1). In another study, Pigati et al. (14) confirmed the previously reported YDB peak in spherules at Murray Springs, Arizona, and also claimed to find several non-YDB spherule peaks in Chile. However, the Chilean sites are known to contain abundant volcanic spherules (22), and yet Pigati et al.(14) did not perform any analyses of candidate spherules with SEM and EDS, which are crucial for differentiating impact-re-lated YDB spherules from volcanic spherules, detrital magnetic grains, framboids, and other spherule-like particles.

        In another study, Pinter et al. (11) claimed to have sampled the YDB layer at a location “identical or nearly identical
        ”with the location reported by Kennett (2–4), as part of three studies that reported finding no YDB spherules or nanodiamonds (11,23, 24). However, the published Universal Transverse Mercator coordinates reveal that their purported continuous sequence is actually four discontinuous sections. These locations range in distance from the site investigated by Kennett et al. (2) by 7,000 m, 1,600 m, 165 m, and 30 m (SI Appendix, Fig. S1 B),clearly showing that they did not sample the YDB site of Kennett et al. (2). Furthermore, this sampling strategy raises questions about whether Pinter et al. (11) sampled the YDB at all, and may explain why they were unable to
        find peaks in YDB magnetic spherules, carbon spherules, or nanodiamonds.

        One fully independent one, with the link broken to the article, but much of the article pasted into the post (Sept 2012):

        http://cosmictusk.com/surovell-comet-asteroid-impactyounger-dryas-edward-vogel-oregon-south-carolina-topper-spherules/

        Here is another blog post. With post comments by George Howard who is sometimes a co-author Unfiltered: Surovell – Holliday in PNAS, 2009:

        http://cosmictusk.com/unfiltered-unsorted-surovell-holiday-et-al-in-pnas-2009/

        –An earlier rebuttal to more failures to replicate–
        The full paper Lecompte et al 2012 “Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis.”:

        Also you might want to take a watch of the slide show presented by Malcolm LeCompte (astrophysicist at Elizabeth City State University in North Carolina)………..
        Abbreviated YDB evidence at 2011 Bern, Switzerland, INQUA Conference:

        http://cosmictusk.com/swiss-bliss-2/

        I think these will give you a good picture.

      • Thank you! Off to recharge, but will go over these carefully tomorrow.

        Fascinating topics – both the Younger Dryas, and the lively debate!

      • People and camps can & do disagree and debate, sometimes on large demographic scales over long spans of time, without it being necessary for anyone to have “screwed the pooch”, or to not “know how to take proper samples from a dig”.

        I – we – needed to see real support for denouncing the competence of Surovell – and several others, and their many coauthors – and that isn’t addressed at CosmicTusk. George Howard, Steve Garcia et al simply have other work-results, interpretations and opinions … none of which puts a dunce-cap on Surovell.

        On the contrary; to all indications Surovell is the solid professional, academic career scientist that he appears to be, and so are the others who publish findings & work at odds with the proposal that a large impact initiated the Younger Dryas.
        =====

        I certainly have no basic personal aversion to the general idea of a big strike at 12,800 ya. I once ventilated excessively at the Carolina Bays phenomena … and am still sentimentally attached to their mystery. Reluctantly, I removed the Bays from the evidence-table.

        The problem with this strike-hypothesis, is the lack of impressive, widespread, compelling evidence of it. The necessity to fuss over details of the sampling procedure, to wax pedantic on the use of the microscope and lab-techniques for sorting tiny artifacts, is inauspicious to the point of irony.

        We’re talking about the virtual obliteration of our world, figurative, geologically, late last week some time’, yet the aftermath of this cataclysm is not glaringly obvious and perfectly well-known to every Junior High kid? I believe the event described would in fact leave “overwhelming” evidence, “most everywhere”, yet the evidence offered is more tentative than thundering.

        I live on the Olympic Peninsula, which was the site of a major terminus lobe and spectacular transition to the Holocene. We don’t have to indulge in fine argumentation to show convincingly the evidence of events 14,000 or 11,000 years ago. They are glaringly and even hair-raisingly clear, even to young children. Tweens soon learn to spot ‘fossil’ shorelines of the extinct Lake Elwha, and labor through Olympic National Park brush, following their contours across the rugged, densely-forested hillsides. They point across the valley and correctly identify where the far shoreline of the now-gone ice-dammed montane Lake would have been.

        And our part of the planet was severely smote 12,800 ya, yet we aren’t all perfectly aware of it, from ubiquitous & prominent evidence?

        Nooo … we know of other events & processes at the same time, and evidence of them is sophomoric to find, assess and understand. Eg, many early-Holocene volcanoes far & wide left big & little calling-card layers in every local bog, and all the lakes. So should have a major extinction-strike in the same time-frame … yet it isn’t there, although it should be easily spotted between other datable horizons. Same story, all across the continent.

      • Ted –
        “I – we – needed to see real support for denouncing the competence of Surovell – and several others, and their many coauthors”

        You obviously did not even bother reading the papers and their “real support”. It’s called laboratory tests – empirical science.

        How Surovell couldn’t even give Daulton proper samples to work with. How Surovell did sloppy science, as opposed to the volumes of testing done by Kennett et al. The lab results mean nothing. Lab results aren’t science to those who don’t want to see actual test results. And Surovell’s bad science put up against Kennett’s – Ted, there is no comparison.

      • Ah, but Ted, Surovell and Pinter and Daulton – they are the ones who put the dunce cap on the YD “team”. Oh, they have mocked. And EVERY time they talk to a science editor, it is with derision and disrespect – always a “Requiem” or “bury the YD impact.” Kennett et al are just trying to do the science.

        And it isn’t a mattre of opinion alone, or interpretation. When nothing terrestrial can achieve 2200°C but the evidence says it got that hot, is it interpretation to say it wasn’t a volcano and wasn’t a forest fire? No, it is admitting what the physics tells you.

        And then Surovell et al are quiet about that – until they have a 50-year difference they want to quibble over – and decalre the wole thing dead again – because of THEIR not wanting anyone to “interpret” anything along lines they don’t approve.

        No, the interpretation b.s. is coming from the other side, while the “forensics” is done over and over and over again – to try to get past this impasse with these “skeptics, without evidence”. People in these comments ask “Well why did it last 1300 years, when no dust can stay in the atmosphere that long?” Exactly! And there is no capacity to address such questions, not yet, not when the basics are beclouded by people who can’t do science right and then take their own inadequacies and declare them superior. So Kennett et al go out and spend another year on ANOTHER “forensic” refutation of their nonsense rebuttals.

        Also, don’t take comments (even by George) at CosmicTusk as more than commentary. The real work is being done by others.

        “The problem with this strike-hypothesis, is the lack of impressive, widespread, compelling evidence of it. The necessity to fuss over details of the sampling procedure, to wax pedantic on the use of the microscope and lab-techniques for sorting tiny artifacts, is inauspicious to the point of irony.”

        The only real “compelling evidence” of a strike that the world will certaiinly accept is a crater. Nothing short of that will convince anyone. And with it seeming to have been in a location that was under maybe half km of ice, a crater may never be found. In case you don’t know it, an impact was NOT what the Kennett et al crowd were thinking about at the beginning. It was the impact material spikes in the black layer – specifically at the BOTTOM of the black layer – that led them to it. Firestone originally was simply looking for why the C14 curves were weird at certain times. Nobody went out and said, “Let’s go out and find some evidence we can claim to have been a comet!”

        If you FIND such materials, just as Luis Alvarez found the Iridium in the K-T boundary, what do you DO with it. BTW, those two layers are the only ones in the geological record, it seems, that are narrow, quite visible layers. That makes them both exceptional and significant. But that layer was an accidental discovery of the whole thing. Like I said, Firestone was just wondering why C14 levels were weird. Then other stuff started showing up as well, and all at 12.9 kya.

        “You go where the evidence takes you.”

      • Ted: “We’re talking about the virtual obliteration of our world, figurative, geologically, late last week some time’, yet the aftermath of this cataclysm is not glaringly obvious and perfectly well-known to every Junior High kid? I believe the event described would in fact leave “overwhelming” evidence, “most everywhere”, yet the evidence offered is more tentative than thundering.”

        Actually, Ted, you are wrong on this, this degree of obviousness. The biologists and climatologists have been working on the YD for a LONG time, wondering WTF???? It’s VERY obvious to them, the ones who have to deal with it professionally. They have been trying to explain it since it was first discovered. It was a VERY significant change in the flora – very noticeable. And if junior high kids were out sampling stuff one to six meters under the ground, YES, they would find it. Find the black layer and wonder about it.

        The evidence is NOT tentative. The understanding of it is, but not the evidence. Those spikes are not tentative. That they all come at the same age – that is not tentative. That they are materials previously always associated with impacts – that is not tentative, either.

        What you have is a group of skeptics who can’t do their own science worth a damn and THEY play little pouting games about how they don’t WANT it to mean what it means to anyone who has dealt with impacts before. They claim it doesn’t mean what it DOES mean. The Pinter people used to work on floods on the Mississippi River and such and forest fires. They have about as much expertise in this as President Obama – yet they don’t WANT it to be true, so they deny any clear presentation of the evidence, pouting all the way.

    • I liked Muck’s book. I think I had a first edition, too. But Muck totally missed it on the Carolina bays. There is zero evidence that they were comet pieces. The shallowness of them precludes hyper-velocity impacts. It doesn’t preclude much slower impacts, like from the ejecta from an impact elsewhere, but a hyper-velocity event has far too much energy to produce the bays.

      And BTW, someone has done an actual count of them, using LIDAR imaging – which shows up ones that are completely invisible to the naked eye. And a LOT of them are invisible like that. They total 43,900. Some people believe there are as many as 500,000, which seems reasonable, but it is only 43,900.

  39. DirkH – 8.2kya is not when Plato dated Atlantis. Plato was about 520BC, Atlantis, by his account, 9000 years earlier = 11.5kya just around the Younger Dryas warming, more or less.

    Platos account would be consistant with a neolithic civilization on the shores of the Med. being inudated by the YD warming.

    • Plato’s account is easily understood by dividing everything by 10, the years, the size of the city walls, etc, which shows that Atlantis was Thera and the destruction was that of the Minoan culture by the Theran volcano. Remembering that 900 years before Plato, the “Pillars of Hercules” referred to the Sicilian pass (later called “Scylla and Charbides”). The Egyptian accounting which Plato recorded in “Timaeus” used units which interchanged by 10.

      • It’s rather funny the way everybody assumes that Plato meant this when he said that, and all on different aspects of his tale. It’s created an industry – “Let’s second-guess Plato!” Some do it on location, some on dating. Like Plato, perhaps the most educated man of his time, didn’t know where the Pillars of Hercules were. And like he didn’t know how to count.

    • Doc –

      That is one of the $64,000 Questions. I am the only one who has even tried to answer that, that I know of. But don’t take that 100 years at face value. No matter what chart you see, the only source we have for temps and timing is GISP2 and other ice cores – and they are LOW res proxies, as are all ice cores. Even TWO hundred years s too high res for them – they can’t really do that. It’s the nature of the bubble migrating a little up or down within the core. Kind of like fuzzy vision. So if you see a ONE hundred year number, you can look at it a s guess.

      Not only that, when you see those steep slopes, they have a straight line between the two points. But the actual line might go straight down from the upper point and maybe even go past the lower one and come back up to it. So that slope is shown at its MINIMUM slope. That 100 years may be 100 days or 100 hours coming up from the lower temp to the upper one.

      In fact, the latest I read on that one was that it was less than a year – and a shorter time even than the drop INTO the YD. Based on what? They start with the one graph, maybe this one, and then maybe find with some other proxy that there should be another point – or maybe the one had a point straight up from the lower one. OR NOT. Who KNOWS?…LOL

      But the short time coming out of the YD seems to have quite a bit of support. If someone knows they haven’t told anybody I know. And the people I know would say if THEY knew.

    • I reckon it was the completion of the melting of what had been a solid Arctic ice cap which started out at miles thick.

    • The sudden end of the Younger Dryas is not unique or mysterious, within the broader Pleistocene, which shows a continuous record of sudden cooling followed by sudden warming, ‘on all time-scales’.

      Events like the Younger Dryas decorate the history of the Ice Ages. That any one of them starts with suspicious suddenness, and/or ends strangely-abruptly, in neither suspicious nor strange, within the overall climatic regime of the Pleistocene.

      Looking at the Ice Ages overall, there is no call for any ‘special dispensation’ on the Younger Dryas. Either to start or end it.

      Explain the Younger Dryas, and we explain the Ice Age.

      • “The sudden end of the Younger Dryas is not unique or mysterious, within the broader Pleistocene, which shows a continuous record of sudden cooling followed by sudden warming, ‘on all time-scales’.

        Events like the Younger Dryas decorate the history of the Ice Ages. That any one of them starts with suspicious suddenness, and/or ends strangely-abruptly, in neither suspicious nor strange, within the overall climatic regime of the Pleistocene.

        Looking at the Ice Ages overall, there is no call for any ‘special dispensation’ on the Younger Dryas. Either to start or end it.

        Explain the Younger Dryas, and we explain the Ice Age.”

        You can deny it all you want. People are coming around. See this NatGeo article with eminent Wallace Broeker (the oceanic conveyor) prominently included:

        http://news.nationalgeographic.com/news/2013/09/130910-comet-impact-mammoths-climate-younger-dryas-quebec-science/

        Some opponents of the hypothesis—and there are many—want so badly for it to go away that they have attempted to declare it dead. “My only comment is that the pro-impact literature is, at this point, fringe science being promoted by a single journal,” one of them, Nicholas Pinter of Southern Illinois University, said last week. The journal in question is Proceedings of the National Academy of Science.

        Other researchers are trying to keep an open mind.

        “Most people were trying to disprove this,” said Wallace Broecker, a geochemist and climate scientist at Columbia University’s Lamont-Doherty Earth Observatory. “Now they’re going to have to realize there’s some truth to it”—though maybe only a spherule or two.

        BTW, PNAS is a journal that the Pinter side has used themselves in the debate.

      • Steve Garcia:

        Little wonder that Wallace Broeker is attracted to the well-falsified YDIH, since he believes that humans caused the natural slight warming from 1977 to 1996, & are still warming a cooling world.

        Anyone who has managed to convince himself that the Modern WP needs a special explanation, while the LIA, Medieval WP, Dark Ages Cool Period, Roman WP, Greek DA CP, Minoan WP, Holocene Climatic Optimum & 8.2 Ka cooling event don’t, would naturally be attracted by special pleading for the totally natural & terrestrial YD.

      • Actually, Broeker is getting smarter in his old age. He has abandoned the Lake Agassiz flood, for example, because the recognized that the ice front had not receded enough and that that drainage path was not open in time.

        In addition, the scouring that would have occurred – there was no evidence whatsoever, anywhere near the southern end of Lake Agassiz.

        That has not prevented others from pushing the same issue, with the outwash going UP NORTH along the Mackenzie River and out into the Arctic Ocean near Alaska. HOW they could think that an outpouring of fresh water into the western Arctic is going to magically stay fresh all the way to the N Atlantic east of Iceland and only THEN sink, it buggers the imagination. I see it as being retarded, myself.

        But I have not seen that Broekers is part of that.

        I had the same attitude toward Broeker as you do. When he backed off the Lake Agassiz ice dam breakup, I was impressed.

  40. Proceedings of the National Academy of Sciences PNAS
    vol. 109 no. 19, Jeffrey S. Pigati et al, 7208–7212
    April, 2012

    Accumulation of impact markers in desert wetlands and implications for the Younger Dryas impact hypothesis

    ABSTRACT

    The Younger Dryas impact hypothesis contends that an extraterrestrial object exploded over North America at 12.9 ka, initiating the Younger Dryas cold event, the extinction of many North American megafauna, and the demise of the Clovis archeological culture. Although the exact nature and location of the proposed impact or explosion remain unclear, alleged evidence for the fallout comes from multiple sites across North America and a site in Belgium. At 6 of the 10 original sites (excluding the Carolina Bays), elevated concentrations of various “impact markers” were found in association with black mats that date to the onset of the Younger Dryas. Black mats are common features in paleowetland deposits and typically represent shallow marsh environments. In this study, we investigated black mats ranging in age from approximately 6 to more than 40 ka in the southwestern United States and the Atacama Desert of northern Chile. At 10 of 13 sites, we found elevated concentrations of iridium in bulk and magnetic sediments, magnetic spherules, and/or titanomagnetite grains within or at the base of black mats, regardless of their age or location, suggesting that elevated concentrations of these markers arise from processes common to wetland systems, and not a catastrophic extraterrestrial impact event.

    A Data Supplement page is linked beneath the PNAS abstract for a PDF of methology & data.

    • Fine point, Ted, I remembered seeing that but could not think where to find it. About the impact event, as Laplace said, “there is no need for that hypothesis”, and Occam’s razor says throw it out.

  41. I think it probably hit the ice sheet, that is why there is not evidence of a crater in the crust. The ice took the hit. melted water ran into the gulf stream, and across the continent.
    iron brian

  42. Re the very rapid warming, watch the video posted above by Robert Schoch.

    http://www.robertschoch.com/plasma.html

    Solar storm.

    Dont forget the eruption of mount Toba induced a thousand year cooling.

    Archeology in Bahamian Blue Holes has revealed massive African dust storms inundating the islands then. This would be in agreement with massive American fire storms, drawing air and dust from Africa.

    • The Toba and 1,000 year assertion is interesting. May I ask where you got that? If Toba’s effect lasted 1,000 years that would mean the YD lasting 1,000 years is not impossible.

      I will be looking into that myself, but if you have a source it could help.

      • The effect of Toba did not last 1000 years. Its effect on weather, not climate, might have lasted six years. Lane, below, finds a mild (1.5 degree C) effect for 20 to 30 years, which would get it into the climatic range.

        In any case, Toba occurred while earth was already well into its cooling process during a major glacial phase, not coming out of one & previously warming, as with the YD.

        And its eruption would have produced far more powerful gas & particle effects than the hypothesized but essentailly evidence-free comet impact.

        http://www.newscientist.com/article/dn23458-supervolcano-eruptions-may-not-be-so-deadly-after-all.html#.VAIi3aNupmc

        http://www.sciencedirect.com/science/article/pii/S0277379101001548

      • Yep, and 1.3 km Fragment G of Shoemaker-Levy 9 had a plume bigger than the planet Earth – in the gravity of Jupiter. The gravity of Jupiter is about 2.5 times that of Earth.

        So, how little of a plume do you think a 1.3 km impact on Earth would be? And that is not to even mention the after effects. And not to mention the smoke from the nearly continent-wide firestorm – of which the black layer is clear evidence.

        Yep, the black layer being all the way over in Belgium is to be completely ignored. And Syria.

        It was just your everyday garden variety brush fire. It didn’t mean anything, and it didn’t have any effects anywhere.

  43. I think alot of the megafauna drowned when all that ice was melting at its most rapid rate. They got stuck on islands that flooded, they died trying to ford across the massive rivers that all flowed south at the time.

    At certain times during the ice sheet collapse lasting more 1,000 years, no animal was getting across the Mississippi river for example unless it had a canoe. The North American continent was isolated into three parts, the ice-sheet north, the west and east.

    It only takes a small change in survival rates, or the number of surviving herds to make a megafauna species become susceptible to extinction.

  44. The Bolling-Allerod (Northern hemisphere warming at 14,600 yrs ago) and Younger Dryas (subsequent 1000 yr cold interval) were parts of the last deglaciation which were driven by oceanographic processes. There is no need for an atmospheric deus ex machina. Over the deglaciation starting as early as 22yrs ago the general picture is steady changes in Antarctica contrasting with unstable fluctuations in the NH driven by the Atlantic Meridional Overturning Circulation (AMOC). The root cause of this is an instability in the AMOC arising from a positive feedback which it possesses.

    Cold water formation and downwelling in the Norwegian sea drives the gulf stream – reactive flow of Carribean warm and – critically – saline water across the Atlantic to north west Europe. This gulf stream water has high salinity, and this makes the cold water formed in the Norwegian sea even more dense than would result from its temperature alone. So this cold and saline water sinks all the way to the Atlantic floor and is one of the principal drivers of the global thermo haline circulation (THC). Now more of this “deep water formation” at the Norwegian sea actually speeds up the gulf stream – something has to replace all that sinking cold super-salty water so this is supplied by the gulf stream. Thus the positive feedback – more gulf stream leads to more cold supersaline Norwegian sea downwelling leading to more gulf stream etc.. Where you have a positive feedback in the system you have the conditions for nonlinear oscillation. This is directly analogous to the ENSO in the Pacific, the positive feedback of the Bjerknes mechanism (cold upwelling strengthens trade winds strengthening cole upwelling etc.) giving rise to the ENSO nonlinear oscillator, although the AMOC operates over much longer – century and millenial – timescales than ENSO (decadal).

    So a basic oceanographic feature comparing the NH with the SH in the palaeo record is more fluctuation and instability in the NH and more stable, gradual changes in the SH. The nonlinear instability of the AMOC is the root of this. Also, there is a clear signature of interhemispheric bipolar seesawing, whereby when the NH moves in one direction, the SH moves in another. This is not universal however – sometimes at the moments of biggest transition, NH and SH move together.

    About 22 kYa (thousand years ago) Antarctica started warming. The NH at the same time slightly cooled. However at about 14 kYa the “Bolling-Allerod” (BA) happened, i.e. the NH abruptly warmed, as evidenced by Greenland cores. This caused a reciprocal pause and slight reversal in the (already long established) gradual Antarctic warming – the bipolar seesaw again. At the time of the BA there was a sharp rise in global sea level – 20 meters in 500 years. Weaver et al 2003 (link below) show that this was caused by a collapse of the gradually warming Antarctic ice sheet. The pulse of fresh meltwater from Antarctica had the effect of speeding up the AMOC and the gulf stream in the NH, bringing rapid warming to the NH and the BA.

    The bipolar seesaw continued – as the NH became sharply warmer, there followed in the SH the “Antrctic reversal” where temperatures went slightly into decline. However down in the deep ocean, interactions between cold bottom water formed in the Antarctic and Arctic caused – about a thousand years later – an abrupt stoppage of the AMOC and the gulf stream. In fact the cuplrit was Antarctic Intermediate water (AAIW) – see again Weaver et al. With the interruption of the gulf stream the NH went cold again – the Younger Dryas. In response – by now you get the picture – the Antarctic turned to gradual warming. After about 1000 years of NH cold with no gulf stream, the effect of the Antarctic collapse subsided allowing the AMOC and the gulf stream to resume. Now followed an exception to the bipolar seesaw – both NH and SH warmed together, around 12 kYa. This marked the final end of the last glacial and the Beginning of the Holocene.

    http://rockbox.rutgers.edu/~jdwright/GlobalChange/Weaveretal_Science_2007.pdf

    http://epic.awi.de/15280/1/Lam2004a.pdf

  45. The scariest thing about the graph is: That the Earth’s temperature maybe many, many degrees cooler on average than we’ve experience over the last 20,000 years?

    • Yes. For most of the last 2.5 million years it has been MUCH cooler. And as recently as 11,500 years ago. The end of the Last Glacial Maximum was at about 18,000 years ago.

  46. Dust from an impact event could have initiated rapid melting by decreasing albedo of the icecap. Even if the dust fall lasted only a short time the decreased albedo would be effective long-term, resulting in the rapid melting and meltwater discharge discussed above, extending for hundreds of years. An impact event (or volcanism) could definitely be a part of this picture. It’s dangerous to attribute these rare events to a single cause when a confluence of factors may be (and probably are) at work. Also, the marked temperature decrease indicated in the ice cores could be an artifact caused by repeated fractionation of O16 away from O18, first by freezing of the glaciers, then by evaporation over the meltwater pool, followed by precipitation onto Greenland.

    http://judithcurry.com/2014/06/04/explaining-abrupt-climate-change/#comment-583781

    • Even if the dust fall lasted only a short time the decreased albedo would be effective long-term, resulting in the rapid melting…

      The trouble with dust-driven melting is that once a thin layer of new snow falls on the dust, it ceases to cause melting. Buried dust has zero effect on albedo.

      Glaciers and icefields commonly contain many dark layers, buried beneath recurring new snowfall. The amount of plant-pollen alone that becomes visible on ice & snow over the course of each summer, can be downright startling.

      Melting is indeed driven by dust, but fresh dust has to be laid down each spring, after the winter snowfall stops. Either that, or snowfall in the cold season has to cease.

      • You can see the effect of tire dust every spring. While precipitation exceeds melting, the dust is indeed buried, but when melting exceeds precipitation the dust layers collect and the snow along side the road melts much more rapidly than elsewhere. That is the effect I am talking about. When insolation is reduced below a certain point and precipitation exceeds melting, the albedo effect accelerates the advance of glaciers. When insolation favors melting over precipitation, a “tipping point” of sorts, than buried dust will be exposed at the surface and a reverse albedo effect will accelerate melting. It is often said that the Milankovitch effect is inadequate to produce the glacial cycles. With the albedo effect working to advance glaciation and the dust accumulation effect working to destroy them, there are powerful amplifying forces at work.

  47. Comets are thought to bring bad luck. What is the origin of this superstition?

    A large comet impact in the ocean could throw thousands, perhaps millions of cubic miles of water high into the stratosphere. Much of this would fall back to earth as ice.

    • Good question. In many, many ancient peoples there are accounts of burning objects or “stars” or “suns” blazing down and causing great noise and quakes and fires. These objects didn’t just appear in the sky one day – they were seen on their way here, as what we call comets, and the archaeologists have normally transliterated as “gods”.

      Any connection with “not having a good day”?

      As to an oceanic impact, we don’t WANT one of those. Hills and Goda tried to calculate the size of tsunami from stony or iron meteors impacting the ocean. The worst case – at 1500 km away – was about 2 km of run-up from the tsunami. I don’t have the source in front of me, but can find it if you’d like.

  48. Something about that dispersal pattern that bothers me. It almost seems backwards. In other words, imagine the winds in the Northern Hemisphere were backwards from what they are today and then look at the pattern. It would look like an impact around Turkey somewhere then dispersed these things across the rest of the Northern Hemisphere. The shape of the pattern given almost defies physics with winds going mainly west to east. One would expect to see relatively little material to the west of the impact site with the amount of debris fanning out as it is dispersed by winds to the east.

    Also, there are a large number of places where such an impact could have occurred but have been completely erased by natural forces. For example, much of what is now under water in the Gulf of Mexico was dry land at that time as the glaciers had not yet melted enough to raise sea levels enough yet. Sea levels would have been about 200-ish feet lower than today so everything that is currently under about 200 feet of water would have been land.

    The Mississippi River would have transported an absolutely incredible amount of sediment from glacial till and loess. You think it is muddy now? When the glaciers were retreating it must have been extremely thick with extremely fine silt.

    One way to find the location of impact might be to sort the debris by weight assuming that the heavier samples settled out of the atmosphere closest to the event.

    • It is possible you are misunderstanding that dispersal map.

      1. The area in N America is not where the wind was taking the dust. That was the area that was burning.

      2. Those only happen to be the areas SO FAR where they’ve found the black layer.

      3. In addition (my guess here) the Heinrich events (of which the YD onset is considered H0) are universally interpreted as “ice rafted debris”. The evidence for the Heinrich events is layers on the N Atlantic, layers of dust. (I originally thought it was talking about full-sized rocks, but then found out it was dust. Given the timing of H0 at the same time as the YD onset, which is the same time as the BOTTOM of the black layer on land, and since the dust reached across to Belgium and to Syria , it seem logical to assume that the dust also fell onto the N Atlantic and sank. If this happened at the same time as H0, then the dust should either be mixed with the H0 dust – or it could BE the H0 dust. It might be an interesting thing to do – to compare, or to see if these same materials are in the Heinrich dust. It is certainly a falsifiable hypothesis, and falsifiable conjectures are what solid science is built on. Of course, if found to be true, this would definitely have repercussions about all the other spikes in the ice cores and the other layers of Heinrich dust.

  49. So there was no new snowfall for hundreds of years that coated the ash and dust with immaculate white stuff.

  50. Other glacial-interglacial transitions during the Pleistocene show the same pattern as the onset of the Holocene.

    The YD & the rapid 8.2 Ka cooling are nothing unusual during deglaciations. In fact, they’re similar to Heinrich Events during glacial phases, the periodic armadas of icebergs launched into the North Atlantic from the Canadian, Greenland, British & Scandinavian Ice Sheets.

    • I agree – its about ocean circulation driven bipolar seesawing plus the effect of freshwater pulses from ice cap collapse during deglaciation. See my post 8 posts upstream.

    • At the same time, you should understand that nobody knows the causes of those other “nothing unusuals” during deglaciation. But you should also include the D-O events BEFORE the deglaciation.

      Saying that they are there in the ice cores is one thing. Saying that these two are explained because of the existence of the others – which are unexplained – doesn’t answer anything.

      As to the Heinrich events, the YD onset is pretty much accepted as Heinrich event H0. The YD caused dust to fall across the Atlantic. Heinrich events are interpreted as due to “ice rafted debris” – DUST – in the N Atlantic sediments, one of which, H0, coincides with the YD onset. Both are about dust. Could there possibly be a connection? Even if it isn’t accepted as such, if both happened at the same time then there should be YD onset dust mixed in with H0 dust. And that could mean what? Among other things, the idea that the H0 dust is ice rafted debris may need reinterpreting. (DO NOT take this as part of Kennett et al and their YD research; this is just my own thinking.)

    • “Other glacial-interglacial transitions during the Pleistocene show the same pattern as the onset of the Holocene.

      The YD & the rapid 8.2 Ka cooling are nothing unusual during deglaciations. In fact, they’re similar to Heinrich Events during glacial phases, the periodic armadas of icebergs launched into the North Atlantic from the Canadian, Greenland, British & Scandinavian Ice Sheets.”

      No. You are only going by the ice cores. These are not just things that show up on that curve.

      The YD IS a very unusual and unique period in the Pleistocene. It was first noticed by climate scientists and biologists, and tehy have tried to identify its causes for a very long time.

      The 8.2kya is not just about cooling. It is about the impact it had on forest fires, vegetation response, sea levels, etc.

      BOTH of these periods have a long way to go before we fully understand what happened. It isn’t just pointing at a graph and noting that there was a blip.

      Similar to Heinrich events? Do we really know what caused Heinrich events? They say “ice rafted debris.” And where did that come from? It was dust settling to the bottom of the N Atlantic – at the same time the (proposed impactor caused) continent-wide conflagration in N America was sending smoke and dust across to Belgium and Syria. If both happened at the same time, then there should be N American continental dust in the Heinrich dust.

      And that is exactly what is there.

      But they looked around for a mechanism within Gradualism and decided it was icebergs.

  51. “nanodiamonds, the production of which can be explained only by cosmic impact..”

    I suppose it is redundant to say the diamonds are made from plants and animals – a kind of grisly observation to comtemplate – this is real climate change impact!

    Steve Garcia
    August 29, 2014 at 1:50 pm

    “none of their “requiem” team was an archaeologist, with experience taking careful samples from the side of a pit.”

    Geologists probably taught archeologists this skill. Indeed for a job like this, I’d go with the geologist/paleontologist.

    • Not so. Archaeologists have to get more precise samples. One inch can be 500 years. For geologists, what do they care about 500 years? For archaeologists 500 years is twice the life of the USA.

  52. Suffice to say for now that this premise has been on the table for a long time. I even wrote a book on the event in 2009 “Sudden Cold” An Examination off the Younger Dryas Interval. Also Steve Garcia is correct when he states there were other lesser impacts likely at about 4200 BP and 8200 BP., and too at 3600 BP, 500 A.D. and 1500 AD. I also think that in addition to the map of YD coverage that Africa was also affected by the 12800 BP, as many animals became extinct there also. I am just in the process of writing a book on the Ice Age mammal extinction as well. Thank-you Rod Chilton, http://www.bcclimate.com

  53. Humans were responsible for the megafauna extinctions. Natural climate perturbation of the glacial maximum followed by the BA and YD probably contributed to this.

    • Actually, it isn’t so cut and dried as that. The Overkill hypothesis is just one of (now) four competing hpytheses.

      1. Overkill
      2. Climate change
      3. Disease
      4. Impact

      1, 2 and 3 do not explain why Clovis man himself also went extinct at that same time. It was another 1000 years before others showed up in the record. Overkill people never mention that one.

      As to the BA and YD contributing, why didn’t the earlier D-O events – dating back to 110,000 years ago – cause these extinctions?

      • D/O events occur during glaciation. The YD was during deglaciation, when previously prevailing temperatures were much warmer.

        Climate change doesn’t work, since many of the same species survived earlier deglaciations & interglacials. The same pattern of Older Dryas cooling, Allerod warming & YD cooling appear in prior deglaciations, leading to interglacials. The difference between the Holocene & prior transitions was effective human big game hunters.

        Overkill advocates most certainly do deal with the effect of over-hunting on humans. There is no evidence that they went extinct after first appearing in North America. Humans are omnivores, not obligatory big game hunters. In fact, human numbers greatly increased after the Clovis/Folsom transition. The two tool industries overlap, so the putative 1000-year gap doesn’t exist.

        The impact hypothesis of megafaunal extinction doesn’t explain extinctions in other parts of the world unaffected by a hypothetical impact on the NH ice sheet, unless the YD cooling can be shown physically to have caused the YD. The Null Hypothesis is that the YD is no different from the thousands of other such abrupt climatic shifts in the paleoclimate record of the Pleistocene.

      • “D/O events occur during glaciation. The YD was during deglaciation, when previously prevailing temperatures were much warmer.”

        Actually, D-O events carried over and became known as Bond events, during the deglaciation of the Holocene. Same frequency, and in-phase. With the YD onset being in both sets. MANY people consider this to be the case. It MAY not be true, in the end, but evidence suggests strongly that it is.

      • “Climate change doesn’t work, since many of the same species survived earlier deglaciations & interglacials. The same pattern of Older Dryas cooling, Allerod warming & YD cooling appear in prior deglaciations, leading to interglacials. The difference between the Holocene & prior transitions was effective human big game hunters.

        Overkill advocates most certainly do deal with the effect of over-hunting on humans. There is no evidence that they went extinct after first appearing in North America. Humans are omnivores, not obligatory big game hunters.”

        Correct on that last point.

        1. 95% of Clovis people lived in the SE USA (based on the number of Clovis sites, which are QUITE numerous)
        2. There are ZERO mammoth kill sites in the SE USA.
        3. Wouldn’t you think that they would have killed a few mammoths near where they lived?
        4. Why would they go out to Arizona and Montana from Georgia or Alabama, just to kill a 5-ton animal – to carry 3 tons home? ON FOOT?
        5. There are at last count only FOURTEEN Clovis kill sites. And ALL of them area out of the range of that 95% Clovis site area.
        6. N America is like 98 MILLION square miles.
        7. Clovis entire history in the world only lasted about 250 years.
        8. Lifespans back then were about 25 years.
        9. The Overkill Hypothesis was thought of when it was assumed that Clovis ONLY hunted and ate Mammoths and other megafauna.
        10. Anthropologists only now are discovering that Clovis hunted and ate rabbits and deer and elk and bear and foxes and raccoons, etc. They ARE revisiting their Mammoth extinction machine understanding of Clovis.
        11. Clovis points did NOT come from over the land bridge at Beringia. The tool technology in NE Siberia is another tech altogether.
        12. The only close relative to the Clovis point is the Solutrean point from Spain and France. As long as the Clovis Barrier existed (saying that no one was in the Americas before Clovis at 13,300 years ago) there was a 5,000 year gap between Solutrean points and humans in the New World. Since 1997, when the Clovis barrier was broken, human evidence in the New World has been pushed back to more than 20,000 years – about a 2,000 years overlap with Solutrean points – plenty of time for Clovis to develop from Solutrean. So now there are researchers who assert that the Solutrean point came with people from Europe, and the people came much earlier. And if they did, they would have most naturally come to the SE USA – right where we find 95% of the Clovis sites.

        “In fact, human numbers greatly increased after the Clovis/Folsom transition. The two tool industries overlap, so the putative 1000-year gap doesn’t exist.”

        No. The gap in the sediments is clear, There is Clovis, and then a gap. And then the next artifacts. 1,000 years later.

        “The impact hypothesis of megafaunal extinction doesn’t explain extinctions in other parts of the world unaffected by a hypothetical impact on the NH ice sheet…”

        Now this one I will give you. I agree. How did that happen? But no one researching the YD has time now to get to that. Give it time. They are too busy dealing with Surovell’s sillinesses. I don’t understand why. They should shrug him off like a fly.

        And, of course, you DO know that the Siberian mammoths food supply does not actually live at the latitudes in which the mammoths are found. You know that, right? The flora only live north to about 55°. So THAT problem also needs to be addressed. And its not like the mammoths like were spread out up to the Arctic cost. The vast majority of those found are really close to the coast. And on the New Siberian Islands, too. And in the water in between the coast and the island. And then they need to explain why the ones there on those islands died while the pygmy runt ones 300 k to the east survived.

        Yeah, one thing at a time. They really don’t have unlimited numbers of people or grants, so they can only take them in order of priorities.

      • You are right of course that it is not so simple. However recent research seems to point to human hunting. Note that the modern human arose about 70,000 years ago. So it was after this that they got really good at hunting. If populations such as the Clovis hunted their source of food and clothing to extinction its not so surprising that they went extinct.

        The contemporary Inuit herders of caribou in north Canada and the Eveni/Chukchi reindeer herders of Siberia are the survivors of that era, having learned to live with their animals rather than exterminate them.

      • “You are right of course that it is not so simple. However recent research seems to point to human hunting. Note that the modern human arose about 70,000 years ago. So it was after this that they got really good at hunting. If populations such as the Clovis hunted their source of food and clothing to extinction its not so surprising that they went extinct.”

        No. Only SOME recent research seems to point to human hunting as the cause. Just as much work is going into climate as the cause. And less work is also being done on illness as the cause. And you are staring at work right here that points at impact. All FOUR lines are being worked on at this time. You can’t point at only one and pretend the others aren’t happening.

        Modern humans rose 200,000 years ago.

        If humans were so good at hunting, why only some of the megafauna went extinct via humans? Bison, elk, deer, bears of many kinds, etc., all came through.

        Do remember that when the Overkill theory came up, Clovis was only supposed to have been here for about 300 years. N America is 8 million square miles. Just try envisioning not only the hunters had to cover the entire continent in 300 years, but they had to prevent any animals from wandering around the end of the hunters’ line, back to where the hunters just left. How do they prevent that from happening?

        Add to that that only 14 Clovis-mammoth sites have been found. And all of those are in the area of N America where 95% of Clovis wasn’t living.

  54. Ted Clayton
    August 30, 2014 at 7:53 am

    Even if the dust fall lasted only a short time the decreased albedo would be effective long-term, resulting in the rapid melting…

    The trouble with dust-driven melting is that once a thin layer of new snow falls on the dust, it ceases to cause melting. Buried dust has zero effect on albedo.

    Robertvd
    August 30, 2014 at 9:38 am
    So there was no new snowfall for hundreds of years that coated the ash and dust with immaculate white stuff.

    Your assertion that dust covered with snow does not contribute to melting is wrong.
    Snow is not a perfect reflector from the surface, it is white and has high net reflectivity due to internal scattering. That means that a significant fraction of the incoming light penetrates some distance into the snow. (the walls of a snow cave/igloo have to be quite thick to completely block outside sunlight.

    Anyone who has lived in snow country knows that in the spring you have snow piles covered with a dark crust as the imbedded dust gets concentrated at the surface as surface layers melt off. My early spring these snow piles will have a black crust on them just a few hours after being dusted with fresh snow as the imbedded dust quickly melts off the snow cover.

    Even apparently clean snow sweeps dust out or the air as it falls and this accumulates in the surface melt layer. The return to high albedo after a snow fall only lasts for a few hours to a day or two depending on the sun light intensity. Once we get into late April early May (northern hemisphere) the sun is high enough at temperate latitudes to quickly penetrate deep into a snow layer and melt off the clean white snow cover. Here in Colorado we can lose 6-8 inches of snow a day to such melting and with a little down slope wind to warm things we can lose over a foot of snow a day to rapid melting.

    • Larry Ledwick said @August 30, 2014 at 12:42 pm

      Your assertion that dust covered with snow does not contribute to melting is wrong.
      Snow is not a perfect reflector from the surface, it is white and has high net reflectivity due to internal scattering.

      While indeed not “perfect”, it takes less than an inch of snow to turn an asphalt road surface as white as a foot of pristine snow.

      Melting from below will be observed on highways, early in the snow-season, but that is usually due to stored heat in the roadbed. Later after sustained cold weather, a light skim of snow will survive on partially-visible asphalt for days.

      I do believe that dusting of permanent (or would-be perennial) snow/ice fields is hugely important. I.e., I suspect we could stop or heavily moderate the onset of a full-blown Ice Age, with a fleet of specialized heavy-lift aerial dusters and carefully-developed carbon or soot particles … which were very extensively explored, developed and applied, more than a century ago. The patents are already lined up on the shelf, waiting for us.

      But annual snowfall is a different critter from perennial formations, and the timely application of dusts would be required, late-winter, early-spring. Sometimes, the tired flight crews would just have to go back up and do it again.

  55. Proceedings of the National Academy of Sciences PNAS
    vol. 111 no. 21, David J. Meltzer et al, E2162–E2171
    May, 2014

    Chronological evidence fails to support claim of an isochronous widespread layer of cosmic impact indicators dated to 12,800 years ago

    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.

    Link to data tables, methodology and supporting information, in the Footnotes.

      • And good riddance, too. Never posit divine intervention (or its equivalent) where a mundane explanation will do. As I wrote above, during the ice age it is likely that the Arctic ice cap was miles thick, maybe even solid ice down to the bedrock. When the Earth started warming, that solid ice cap would initially be undisturbed and so the main part of the planet would warm quickly. But as sea levels rose from the melting of the continental glaciers, eventually the Bering Strait would open again and the solid Arctic ice would be attacked from both Atlantic and Pacific side. Eventually an under-ice channel would connect the Atlantic and Pacific causing rapid ice melting and so feeding of freezing-cold water into the oceans. So the Earth would rapidly cool again. So here’s the question for you all: How long would it take the Earth to melt out that solid miles-thick block of Arctic ice? I’d say, about the length of the Younger Dryas. Once it was all melted, a thousand years later, the Earth’s temperature could rise again to the new warmer level. I suggest previous ice ages would show a similar pattern if we had detailed enough data.

      • NZ Willy –

        “As I wrote above, during the ice age it is likely that the Arctic ice cap was miles thick, maybe even solid ice down to the bedrock.”

        Inform yourself of the actual thickness. It was 2 km (about 1.6 miles) and then only at the glacial max, and then only at the thickest point – which was up near the east side of Hudson Bay. Near the fringes it was naturally thinner, and probably thinned quite rapidly right close to the edge.

        “When the Earth started warming, that solid ice cap would initially be undisturbed and so the main part of the planet would warm quickly. ”

        I love when people invoke this mysterious warming. They don’t explain it. (They can’t, of course.) They just say, “when it warmed”, blah, blah, blah) with absolutely no explanation needed for WHY it warmed. It is taken on faith that SOMETHING did it, but then they blow off actually looking into it.

        Hey, I don’t know the answer myself, but it bugs the hell out of me when people just reach into the “reasonable portion of the brain” (meaning their arses), pull out a speculation, and then go on, as if it is now explained from on high.

        It’s not a speculation, THAT the Earth warmed. But WHY? Nobody even bothers asking.

        There it is in the GISP2 core and others – RAPID freaking warmups and cool-downs, ones that make modern global warming look like a gnat on an elephant’s arse. It is HUGE, and all we have are these PUNY , little micro-forcings like CO2 and cloud albedo, and cosmic rays – none of which are worth SQUAT on the modern global warming stage. But then there are 13°C, 14°C (23°F and 25°F) drops and rises in perhaps a year or so at the YD and everyone goes, “Ho hum,! More global warming (cooling), What’s new?”

        WHY it warmed up IS A BIG DEAL. And everybody just sloughs it off with a wave of the magical Harry Potter wand.

        “But as sea levels rose from the melting of the continental glaciers, eventually the Bering Strait would open again and the solid Arctic ice would be attacked from both Atlantic and Pacific side. Eventually an under-ice channel would connect the Atlantic and Pacific causing rapid ice melting and so feeding of freezing-cold water into the oceans. So the Earth would rapidly cool again. So here’s the question for you all: How long would it take the Earth to melt out that solid miles-thick block of Arctic ice? I’d say, about the length of the Younger Dryas. Once it was all melted, a thousand years later, the Earth’s temperature could rise again to the new warmer level. I suggest previous ice ages would show a similar pattern if we had detailed enough data.”

        Don’t forget that the Last Glacial Maximum ended at 18 kya. That gave it most of the next 5,000 years to melt back – which it did. And it DID re-extend during the YD, but it would have been 1,000 years re-growing areas tht had taken 5,000 years to melt. It is a certainty that the ice had not re-grown its entire thickness.

        Now, in Michigan the Mason-Quimby line clearly shows how far down the ice had come – about midway down the lower peninsula. Mammoth bones and paleo-Indian artifacts clearly go that far and no farther. That area did have Clovis. The Gainey site is there.

        At LGM the ice had gone all the way down nearly to I-70 in Indiana, if not elsewhere.

        BTW, there was an event called the Kankakee outwash (in SW Michigan) similar to the Harlan Bretz Scablands flood, but on a much smaller scale. That is dated basically to the end of the YD. (Which actually doesn’t make sense, because the ice then didn’t go down that far.)

      • NZ Willy:

        Science does have detailed enough data & prior glacials, deglaciations & interglacials do show the same pattern, as I commented before. During deglaciation, outflows of glacial fresh meltwater are implicated in at least some of the sudden cool intervals.

        This study found abrupt, millennial scale cooling periods during the long MIS 11 interglacial, for instance. MIS 11 was even warmer & lasted about twice as long as the Eemian, itself warmer & longer in duration than the Holocene so far.

        http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&ved=0CG4QFjAI&url=http%3A%2F%2Fwww.clim-past.net%2F6%2F31%2F2010%2Fcp-6-31-2010.pdf&ei=sjQCVNHjE-WiigKyh4DQAw&usg=AFQjCNHJdGDUmhzh6ipELSw-BLLkXvGGBQ&sig2=KTTbxQ9JTKvgJlfp_-6CBQ&bvm=bv.74115972,d.cGE

        Abstract.

        A synthesis of paleoclimate responses from Lake
        Baikal during the MIS 11 interglacial is presented based on
        proxy records from two drill sites 245 km apart. BDP-99 is
        located in vicinity of the delta of the major Baikal tributary,
        whereas the BDP-96 site represents hemipelagic setting distant
        from riverine influence. The comparison of thicknesses
        of interglacial intervals in these contrasting depositional settings
        confirms the extended ca. 33-kyr duration of the MIS 11
        interglacial. The new BDP-99 diatom biostratigraphic record
        matches that of the BDP-96-2 holostratotype and thus allows
        establishing establishes robust correlation between the
        records on the same orbitally-tuned timescale.

        The first detailed MIS 11 palynological record from the
        BDP-99 drill core indicates the dominance of boreal conifer
        (taiga) forest vegetation in the Baikal region throughout the
        MIS 11 interglacial, since at least 424 ka till ca. 396 ka. The
        interval ca. 420–405 ka stands out as a “conifer optimum”
        with abundant Abies sibirica, indicative of climate significantly
        warmer and less continental than today. The closest
        Baikal analog to this type of vegetation in the history of
        the current Holocene interglacial is at ca. 9–7 ka. The warm
        conifer phase lasted for ca. 15 kyr during MIS 11 interrupted
        by two millennial-scale cooling episodes at ca. 411–410 and
        405–404 ka. Reconstructed annual precipitation of 450–
        550 mm/yr during the MIS 11 interglacial is by ca. 100mm
        higher than during the Holocene; regional climate was less
        continental with warmer mean temperatures both in summer
        and in winter.

        At both drill sites, the two-peak structure of the MIS 11 diatom
        abundance profiles reflects the orbital signature of precession
        in the interglacial paleoclimate record of continental
        Eurasia. MIS 11 interglacial was characterized by the sustained
        high level of primary production and accumulation of
        autochthonous organic matter at both study sites. The responses
        of paleoclimate-sensitive indices in the mineralogy
        of the MIS 11 sediments in BDP-96-2 are consistent with
        those during the Holocene. Illitization of secondary clay
        minerals in the Baikal watershed was an important process,
        but it appears to have been subdued during the first half of
        the MIS 11, apparently due to elevated humidity and muted
        seasonality of regional climate.

      • NZ Willy
        Your hunch about ice cap melting would seem to be a good one. According to Weaver et al 2007 there was a collapse of the Antarctic ice sheet at about 14-15 kya. The big melt wayer pulse from this disrupted ocean circulation with the result that the gulf stream was kick-started. This caused the Bolling-Allerod warming (just before the YD). However ongoing complex interaction between a now-cooling Antarctic (bipolar seesaw) and Atlantic deep circulation resulted in the interruption of the gulf stream a couple of thousand years later leading to the YD. See my post at 5:32.

        http://rockbox.rutgers.edu/~jdwright/GlobalChange/Weaveretal_Science_2007.pdf

      • I love it when people talk about the Gulf Stream and leave out the part where its flow goes INTO the Gulf of Mexico and picks up all its what there.

        There is not one oceanic conveyor map in ten that shows it going into the Gulf.

        I also find it ironic as hell that you guys are talking about the oceanic conveyor when just now you were all saying how dumb Broecker is/was. Make up your minds…LOL

        It is not enough that the Gulf Stream is moving NE like it does. Without the heat from the Gulf it is a totally unimportant flow.

        Now, I myself think the oceanic conveyor ans the stoppage of the sinking due to fresh water input – it’s all bunk. I’d love to talk to Broecker himself someday about it.

        Why is it bunk?

        1. In my engineering career I’ve had to work a little bit with convection. And I will tell you, the second weakest force in nature (next to gravity) is convection. You can argue that if you want, but the point is how WEAK it is.

        Cold water sinking is due to convection. But it also has to fight the hydrodynamic lift of the water below that it is replacing. So the downward velocity is dependent on two things – one of which is subtractive.

        2. The force of that sinking is supposed to be what SUCKS the Gulf Stream northward like from 4,000 miles. Not even close to being possible. That sinking ias a micro-forcing.

        3. The convection downward is the END of the process. The rotation of the earth and the winds are what dives the Gulk Stream. At the end, with counter currents fighting it and whatever, the flow simply peters out. And AS it stop, it has a chance to sink.

        4. When you evacuate a region or volume, the lowered pressure allows the fluid to flow to the lower pressure area. But the inflow will come from all possible directions. That means that if the water sinks east of Iceland, half the inflow will be from the northwest and half from the southwest – in fact, from 360° around. It cannot “PREFER” to suck water only from one direction. Suction doesn’t work that way. It scavenges from the EASIEST – meaning the closest. And easiest is not from 4,000 miles away.

        I’ve said this to scores of other people, and no one gets it. I don’t expect you to. Only someone with some sort of practical experience with flows will understand the principles involved.

      • NZ Willy –

        “Never posit divine intervention (or its equivalent) where a mundane explanation will do.”

        You write about this as if you know how the whole thing aqme about – which you obviously do not.

        No one in this YD group had any intention of looking for a comet or meteor strike. Firestone was looking for a supernova in the C14 history. Haynes was just doing his thing at Blackwater Draw. They were led to it by the consistent dating of the samples they kept sending to labs. They kept finding spikes in the uncommon materials in those samples.

        They did not wake up one day and decide to go look for God’s hand in the works. But Gradualists will reject anything, any time that in their minds creeps one baby step toward Catastrophism – because science had searched for centuries to get rid of Noah and his Flood, and Gradualism/Uniformitarianism gave them that crowbar. And once they’d won that war, they aren’t going to let “victory” slip from them in the form of anything catastrophic.

        So, when Shoemaker-Levy 9 had 20 fragments impact Jupiter in 1994, Gradualists looked at that and walked away. They didn’t see that comets hitting Jupiter could POSSIBLY mean that comets could possibly hit the Earth – not in our times.

        And when the rock over Chelyabinsk hit in early 2013, that had no meaning to Gradualists. It didn’t matter that the object came out of nowhere, with no warning – or that the rock could have been 5 tiimes bigger and we could have missed its coming. Or that there are millions of other Chelyabinsks out there that could smack Earth.

        And WHY do Gradualists not worry? Because rocks in space are a natural occurrence. And, being a natural occurrence, rocks in space aren’t “Deus ex machina.” RIGHT?

        So, who is invoking Deus ex Machina? The YD people – who recognize them as comets and meteroroids (rocks in space), not gods.

        NO ONE on the YDIH side is invoking any gods. There have certainly been comets and meteors that have struck the world in its long history. They are rocks, not gods. The giggle is not yours to have. You’ve invoked religion, which nobody on the other side cares a whit about. We have evidence of impacts(though not from any god’s thunderbolts), in spite of the gradualist erosion that has erased most of them. It is real evidence, not holy writ. They are called craters. From rocks. FORMERLY IN SPACE, NO LESS!

        (You DO remember when your brethren scientists insisted that rocks do not fall from the sky, don’t you? It’s only been 210- years since THAT one was debunked – by actual rocks falling out of the actual SKY. By the science of the day – the world’s best minds! – rocks could not fall from the sky.)

        So, now we are finding out that the rocks in the sky are flying along near the Earth all the time. But of course, such rocks couldn’t fall and hit OUR Earth – our exceptional, protected Earth – could they?

        They can hit Jupiter. In fact, since SL-9, two OTHER comets have hit Jupiter – something our BEST MINDS told us would not happen in our lifetimes.

        So, either comets hit planets or not. And either comets hit Earth or not – YOU TWO are the final arbiters on that, right? Do our astronomers who spot one coming our way need to ASK you, before announcing it to the world? Will need to get YOUR blessings before they will be allowed to admit it?

        CONCLUSION: Rocks fall on planets. They re not gods, nor the emissaries of gods. They are ROCKS.

        But if you two want to think they are deus ex machina, go ahead. Others are paying attention to ROCKS.

        You two are a riot.

      • milodonharlani:

        Great, so if every ice age ends with a Younger Dryas – type pattern, then the case is closed, there was no impact event. My scenario of the solid Arctic ice cap is an obvious and complete explanation. Well done.

      • Steve Garcia

        So you are a disbeliever in the Thermo Haline Circulation and the entire discipline of oceanography?

        There is one very simple proof that the oceans are vigorously vertically mixed. Bottom water is oxygenated. If the oceans were stagnant as you argue then bottom water would be anoxic. This is tbe case in confined seas such as the Black Sea – hence its name. But most of the world’s ocean bottom water contains oxygen originating from the surface.

      • Steve, you said that the thickness of the frozen Arctic ice cap was “2 km”, but you’ve forgotten that another few miles of packed ice was likely on top of that, a la Greenland. So 5 miles thick is reasonable. It doesn’t appear on our ice age maps because we have no way to reconstruct it exactly.

      • “Steve, you said that the thickness of the frozen Arctic ice cap was “2 km”, but you’ve forgotten that another few miles of packed ice was likely on top of that, a la Greenland. So 5 miles thick is reasonable. It doesn’t appear on our ice age maps because we have no way to reconstruct it exactly.”

        Well, YOU said ice cap, and I went with that. I meant to say that the ice SHEET max thickness was 2 km.

        But, no, nothing I’ve EVER come across indicated that there was a distinction between “ice cap” and “packed ice”. I wouldn’t agree with that statement at all. I know that the INTENT of what I read a few months ago was that 2 km was the most ice at any one point. Where you came up with that “double ice” from I can have NO clue. There was AN ice sheet – the Laurentide Ice sheet at the LGM – and what I am finding now is that that was 2 MILE thick – about 3 km “but much thinner at its edges” [WIki – but no source given]. I will go with that – 2 km or 3 km at the thickest – not that important. It was hard to find more on this right now. But this was interesting:

        the extent and thickness of a wet, deforming bed beneath the southern LIS have been debated. Boulton & Jones (1979) suggested that the south margin of the LIS was very thin because of low basal shear stress (ca. 5 kPa). Beget (1986) suggested a conceptual model for the Lake Michigan lobe that incorporated a combination of sliding and soft sediment deformation. He suggested that deforming till with a low yield strength (ca. 8 kPa) produced ice-surface profiles with an ice thickness of only 500 m about 200 km north of the terminus.

        WOW – 8kPa is only about 1.2 psi – yeah, LOW yield strength for the ground underneath. NO IDEA how that could support 500 m of ice. 1.2 psi is probably like wet slurpy mud. VERY slurpy.

        (from http://www.geology.wisc.edu/~davem/abstracts/03-25.pdf)

        It evidently is still being debated, as of 2003, at least. 500 meters seems about right 200 km from the south edge. That seems to agree with my sense of it being maybe 100 meters right at the edge, more or less like glaciers calving in Antarctica.

        BTW, that 2 miles was for the LIS. The Wisconinan was after the retreat, so it would seem it would be a bit thinner – but I looked a while and couldn’t find specifics for the resurgent ice thickness.

    • It should be obvious that we are hardcore supporters of science. No evidence; no hypothesis.

      There is nothing the least bit unusual, let alone unique, about the YD. Every deglaciation at least back to 800 Ka shows the same pattern of abrupt cooling & warming.

      Please read the papers which have been posted here dispositive of the falsified YDIH & get back to us. Thanks.

      • For instance, rapid climate shifts in the onset of the Eemian (having already showed same in the super-interglacial, MIS 11):

        http://www.sciencedirect.com/science/article/pii/S0277379199000116

        Abstract

        A study of the 140–100 ka interval in core T90-9P from the North Atlantic (45° N, 25° W), based on analysis of oxygen and carbon isotope records from planktonic and benthonic foraminifera, and from the bulk sediment fine fraction facilitates a detailed paleoceanographic reconstruction of the penultimate deglaciation (Termination II), and of the Eemian interglacial (δ18O stage 5e). The first step of Termination II was characterised by low productivity and a mixed water column, which was a remnant of glacial conditions. A 3 ka period of relatively stable conditions, with a stratified water column (‘Termination II pause’), occurred half-way through Termination II, and preceeded a second and more rapid climatic shift. The end of the deglaciation (Eemian maximum, i.e. isotopic event 5.53) initiated the establishment of strong, seasonal, water column stratification. North Atlantic Deep Water (NADW) production remained low during the complete glacial–interglacial transition. After the Eemian maximum, NADW prodution was restored, and bottom waters remained quite stable during the course of the Eemian, while surface waters gradually cooled in the second half of the stage. A short surface water cooling event accompanied by a reduced seasonal water column stratification and nutrient instability occurred at approximately 117 ka BP.

    • As milodonharlani states, we are following the science, while you are looking for old-style magic dressed up in science clothing. Just because a rock can fall from the sky does not mean that it did. If previous glacials ended with the same YD pattern as the most recent one, that kills your impact theory stone-cold dead, end of story dead, terminated.

      • You guys are the ones who brought up deus ex machina.

        Also, you seem to be thinking that the only evidence for the YD is the ice core graph. The YD was notable long before they ever drilled those ice cores, dudes.

        The YD is NOT “just another blip in the ice cores”.

        But NO ONE here – or elsewhere – is even asking WHY those 13°C swings happened – except to invoke microforcings that today have trouble creating 0.2°C swings. Those didn’t happen from CO2, guys (FAR too insignificant), nor from solar insolation as we know it today (too weak), nor from Milankovitch cycles (too long, too slow, too weak), nor cosmic rays making it cloudy a bit more or less (too weak), nor from ENSO (too weak), or the PDO (too weak).

        And don’t invoke the D-Os and Bond events – because those are only artifacts of the same graphs you are looking at – from the ice core readings. The patterns are there – but not BECAUSE of D-Os or Bonds – which are only recordings of what actually happened. The temps went up and down severely – at least in Greenland and somewhat less in the Antarctic – but WHY? Pointing at the graph isn’t science. It is looking at a representation.

        What did those ups and downs? I don’t know, but the YD is a window into it. Ignore it and pretend vast superiority, but most of this you don’t know much about.

        All I’ve heard is paeans to gradualism and Broecker’s conveyor. You think you know about the climate science, but climate science, as we are given it, is in its infancy and has many errors in it. It is not the done deal you imagine it to be. You sound like the science is settled….LOL

        Gradualism – do you three actually think that what you see in the ice core graph is GRADUALISM? If so, don’t run around bragging about your powers of perception. 13°swings in less than a decade – and that was done by internal forcings? Think about how illogical that is. The world around you is gradualism. If the world got 13°C colder tomorrow or in the next decade (the YD happened much faster), how much will that shake your understanding of the world? That is what Clovis man faced – and something in there did him in, along with some of the animals he hunted. And it shouldn’t have – because humankind had lived most of its life in ice ages. So, you say it was the cold that got him? I sure as hell don’t. I guarantee you it wasn’t gradualism that killed him off.

  56. Steve Garcia
    August 30, 2014 at 2:21 pm

    Geologists today are neither uniformitarian “Gradualists” nor catastrophists. It has been understood for decades, at least, that both schools of thought are valid. Even Lyell acknowledged that events such as floods can & do occur, with geological consequences.

    That’s not the issue here. The point is that there is not enough evidence to support the YD Impact Hypothesis, & overwhelming evidence against it.

    Again, please read the recent papers showing the nanodiamond conjecture false, upon at least two separate grounds. And please respond to my previous comments on the pattern of megafaunal extinctions, both in the Americas & on other continents.

    To mention again one example I cited, consider the demise of the giant ground sloths. While wiped out on the North & South American mainlands early in the Holocene, they survived for another 6000 years on Caribbean islands, until in their turn seafaring humans apparently wiped them out there as well. Ground sloths, it should be noted, inhabited the continental tropics (& south temperate zone) in environments similar to those on the islands, even farther away from the alleged impact site in Quebec or thereabouts.

    http://www.pnas.org/content/102/33/11763

    Asynchronous extinction of late Quaternary sloths on continents and islands

    Abstract

    Whatever the cause, it is extraordinary that dozens of genera of large mammals became extinct during the late Quaternary throughout the Western Hemisphere, including 90% of the genera of the xenarthran suborder Phyllophaga (sloths). Radiocarbon dates directly on dung, bones, or other tissue of extinct sloths place their “last appearance” datum at ≈11,000 radiocarbon years before present (yr BP) or slightly less in North America, ≈10,500 yr BP in South America, and ≈4,400 yr BP on West Indian islands. This asynchronous situation is not compatible with glacial–interglacial climate change forcing these extinctions, especially given the great elevational, latitudinal, and longitudinal variation of the sloth-bearing continental sites. Instead, the chronology of last appearance of extinct sloths, whether on continents or islands, more closely tracks the first arrival of people.

    • Okay – Paper read and digested. All of the dates presented were uncalibrated C14 dates BP, so I had to convert to real time, calibrated (via IntCal13). So the “cal BP” dates below are mine and I can defend them, even if they are slightly off. You can go check my work using the paper and IntCal13.

      “Years BP” numbers are generally about 2,000 years lower than cal BP dates. So, if you thought any of these lived for 2,000 years after the YDB, you are mistaken.

      Basically the paper is an anti-climate-forcing argument, in favor of Overkill. It says nothing about impacts.

      In the Supplmental Text, this is discussed in the preamble to that:

      Even more problematic are apparently anomalous dates that lie far outside the range of previously accepted LADs. Such dates should be regarded with skepticism (20). Reanalysis of the material originally submitted for dating may help to identify and reject false dates if contamination or laboratory procedures were the source of error. Until that is done, the significance of an anomalous date cannot be properly assessed. We identify several such dates (see Supporting Text, which is published as supporting information on the PNAS web site) whose validity has not yet been demonstrated by means of replication or other critical evaluation.

      Thus, some late dates need stronger provenance and are suspect.

      Hahaha – You know where I am going with THAT one, don’t you?…LOL

      Seriously, though…

      All the dates actually presented (in the main body or in the supplemental text) were 12715 cal BP or before. The text in the conclusions states that, “no remains of megafaunal sloths or any other large, extinct mammal in either North or South America have been reliably dated to within the last 10,000 14C years (≈11,600 cal BP)” – which seems to be the only calibrated date given. However no source for that date is given.

      Almost all the dates are 12,600 cal BP or earlier, and only 2 at that date. The rest are either right on the YDB or earlier.

      So, the question comes up – Where does that 11,600 cal BP come from? (“Trust but verify”.)

      And the other is how can we explain the 12,175 and the 12,600 cal BP dates within an impact scenario? IS that impossible to do?

      I don’t know. (I don’t have unlimited access to papers – paywalls and all that.) The animals would all not have died at the same second. If some resources survived, some animals would have found them. Could they live for 200 years in some locales. I have no idea. If the resources are there and they stayed and the resources kept growing, why not? Could isolated families have survived for some time? I have no idea.

      Am I clutching at straws? No. I am not gooiing to draw conclusions basd on one paper. (You can’t believe the wide assertions made in so many papers – all over the maps, and so many contradicting each other. If you haven’t run into that you live in a sequestered world.)

      This is the first paper I’ve seen in quite a while with actual dates. I have a LOT of other things I read, and this i but one of many to go after. That is one of the FUN things about the YDB – its tentacles go everywhere, so I am not often bored.

      There were 32 other megafauna species that went extinct at the YDB. Until I look at enough of them, I can say these dates may be outliers.

      I have a PARTY to go to! GOOD BYE FOR TONIGHT, GUYS!

  57. Steve Garcia
    August 30, 2014 at 2:40 pm

    Clovis people in the SE US killed & ate the animals available to them. There were mammoths in FL, but much of the environment in the SE was not ideal habitat for mammoths. However, there is a pre-Clovis mammoth kill site in WI, & a mastodon site in WA.

    http://www.sciencemag.org/content/334/6054/351.short

    As for your unfounded assertion regarding the supposed depopulation of North America, please read this recent JAS paper. The Clovis & Folsom peoples might have been of different geographical origin, but they clearly overlapped in time on this continent:

    http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CCgQFjAB&url=http%3A%2F%2Fwww.unm.edu%2F~marcusj%2FCollard%2520et%2520al%25202010.pdf&ei=xEcCVP2rPMPiiwL8uYDADg&usg=AFQjCNGEwkebuty9RmvhtgFmlw53lkCHpw&sig2=NUEPPoRLuzOCb9McOdil2A&bvm=bv.74115972,d.cGE

    Spatiotemporal dynamics of the Clovis-Folsom transition

    a b s t r a c t
    Despite the importance of the CloviseFolsom transition for understanding the history of western North America, its spatiotemporal dynamics remains unclear. Here we report a three-part study in which we investigated the transition using radiocarbon dates from Clovis and Folsom sites. In the first part of the
    study, we used dates from Folsom site-phases to determine when and where Folsom originated. In the second part of the study, we employed Clovis and Folsom dates in analyses designed to determine whether Folsom spread via demic diffusion or cultural diffusion. In the third part of the study we investigated the velocity of the Clovis-Folsom transition. The analyses suggest that Folsom first appeared around 12,800 calBP in the northern High Plains and spread north and south from there. They also suggest that the spread of Folsomwas, at least in part, the result of population expansion. In addition, the
    analyses indicate that the spread of Folsom was relatively fast for a prehistoric diffusion but well below the maximumvelocity that has been estimated for such events. These findings, in turn, have implications for the hypotheses that have been put forward to explain the CloviseFolsom transition. They refute the
    idea that the CloviseFolsom transition resulted from an extraterrestrial impact over northern North America at 12,900 100 calBP but are consistent with the alternative proposal that the transition was a response to climate-driven environmental change.

  58. Steve Garcia
    August 30, 2014 at 2:56 pm

    If Clovis people didn’t hunt mammoths, why do Clovis points show up at mammoth kill sites, as at the classic Lehner, Colby & Naco sites, for instance?

    Now you’re getting downright nonsensical.

    • Who said that Clovis did not hunt mammoths at all? I didn’t. You aren’t reading me clearly. It doesn’t help if I say something and your brain twists it around

      What I said was that of the 14 mammoth-Clovis kill sites not ONE was in the normal Clovis homeland in the USA SE. The nearest were up in MN near the headwaters of the Mississippi River.

      What all that means I don’t know, but why are there no Clovis-mammoth kill sits in the USA SE? There are HUNDREDS of Clovis sites in the SE, but no mammoths included. And what in the hell were Clovis people doing so far from home killing animals that weighed 5 tons or so? They certainly didn’t take it all back home to Alabama with a banjo on their knee.

      I hope that is a little clear to you now.

      • Your confusion arises from your mistaken belief that all Clovis people lived in the SE, which it should have been obvious they didn’t. Clovis people lived all over the present USA, not just in the SE, as should be obvious from where their points have been found. Do you seriously imagine that western mammoth kills were made by bands immigrating from the SE, to return there?

        If so, you really ought to study archaeology & paleontology before presuming to comment upon those subjects.

        Few if any mammoth kill sites have been found in the SE for the simple reason that there were fewer mammoths there & the environment didn’t favor site preservation as well as in the West. Clovis hunters in the SE favored other game species because they were more plentiful & easier to kill.

        Please elucidate whatever point it is that you are trying to make.

  59. Anthony, it would be worthwhile to do a followup on this, either authored by milodonharlani or using the materials & citations provided here by him. YD was not an impact event because previous glacials also ended with a YD pattern, it seems — which would kill the impact theory “stone cold” dead.

    • Ted & others have also posted valuable comments with links to studies debunking in detail this hypothesis, including yourself & Phlogiston, et al.

    • It’s been a lively review here of the broader debate that’s been ongoing across several science-disciplines, for several years now.

      One of the reasons this debate gets attention, is the level of public interest in the topics it touches on.

      • Very interesting that you go find all the CON papers and don’t bother looking for the PRO ones or the rebuttal ones. Real objective approach, dude.

        You three guys are basically trolls then, on here, simply to leave everyone with a bad tste in their mouths. Nice citizenship – force it down people’s throats.

        Well, the reality is this:

        With or without your subjective approval and closed minds, this issue is being debated and people are being won over by it. Your efforts at giving all of this the bum’s rush doesn’t change any of that. You won’t go actually READ anything that rebuts Holliday, so there is no hope for you.

        But one really good thing that came out of this is that I found some great papers last night that support what I’ve been saying. THANKS! And have a nice closed-minded life, each of you. I wish you the best.

      • Dr. Holliday’s backgrounder was key in helping me see how the issue arose. His wrap-up ties a lot together, and cuts to the chase as straight citation & reference following does not. That’s a great link to include here, milodonharlani!

      • Steve Garcia said @August 31, 2014 at 3:23 am

        You three guys are basically trolls then, on here, simply to leave everyone with a bad tste in their mouths. Nice citizenship – force it down people’s throats.

        It’s a science-debate, Steve, and even more-cleanly so than many of the generally sci-tech issues that arise on WUWT.

        But the true locus of this debate is not WUWT at all – it’s the wider, authoritative Science institution & community. They are the debaters. Our role here, is more to just ‘report’ on the debate as it has been unfolding in the official science-world.

        It would be undue self-flattery (if not self-deluding), for me to image I am ‘weighing in’ on the actual science-conversation. My role is to “report”, and that’s been my emphasis … looking at top-ranked peer-reviewed journals where the back-and-forth of the actual debate has been recorded, and placed in full public view.

        The best we can achieve here, is to bring the science that is being ironed out in the real science-professions, to the attention of the general public, and possibly some media-folks.

        To that end, I will continue to ‘abuse’ WUWT with citations to legitimate sources like PNAS.

      • Steve Garcia

        I should point out that my main aim here is not to dispute that comet or bolide impacts may have occurred around the YD. I haven’t researched this enough to say one way or another. However I doubt that impacts can be or need to be a sufficient explanation of the YD since there is a well established and scientifically well grounded body of oceanographic models (yes that m word) this time in close agreement with substantial experimental data (unlike CAGW) showing the BA – YD – Holocene inception as well understood centennial and millenial scale ocean circulation processes. (Sorry for the long sentence.)

        These oceanographic processes are currently the focus of a pivotal debate at Judith Curry’s site following from the recent Tung and Chen “the ocean ate global warming” paper. JC is arguing, cprrectly in my view, that in pointing to variation in ocean vertical mixing as an excuse for the pause, T&C have pointed to what is likely to be the dominant mechanism of purely natural climate variability on decadal to millenial timescales. This is being opposed by Gavin Schmidt who says the climate system including ocean is at equilibrium and passive and only changed by outside forcing. This AGW position is extremely weak, lacking any insight into complex dissipative thermodynamic systems.

        To summarise, existing knowledge of ocean circulation effects on climate has the possibility to fatally undermine the flawed CAGW passive climate paradigm, now that they have been forced to invoke ocean processes to “explain” the pause. It will do much more than that – it could terminally unravel the catastrophist AGW narrative.

    • I agree that more in the YD would be good. As a period with distinctive climate ups and downs with first an abortive then a “successful” deglaciation, accompanied by good geological and oceanographic data, the YD could serve as a “Rosetta stone” of ocean circulation driven climate change.

      This could provide solid underpinning of the null hypothesis of the “normalness” of climate fluctuation, on a range of timescales. For me the terms “climate” and “climate change” are almost synonymous.

      Another major interest in the YD of course is the megafauna extinction on which milodonharlani is clearly an authority.

  60. I recently found out that evidence abounds for a 5 to 7 hundred foot tsunami took out the pacific population about this time.

      • Oh Lord, I left that Edgar Cayce stuff behind when I turned 20. But “Timaeus” by Plato is still on my bookshelf, wherein Plato states that his accounting is taken from what the Egyptian priests told him — he just passed it on. Chinese whisper rules apply.

      • Younger Dryas Impact Hypothesis: “I would run screaming away

        John Hawks is Prof. of Anthro at Wisconsin, internationally active at leading digs, and runs a fine science blog, JohnHawks.net.

        I knew Hawks had a downbeat post on the YDIH, and returned to look closer. Things went downhill from there, fast. The Younger Dryas impact fizzle? [Oct 2009]

        On that post, I clicked on his “Impacts” tag, above the title, for several related posts. The latest, May 2011: “I would run screaming away”.

        There, Hawks cites science-writer Rex Dalton’s piece, Comet Theory Comes Crashing to Earth

        Both Hawks and Dalton point to multiple serious-to-grave irregularities with the ‘YD Comet Project’.

        While there’s lots in those posts … here’s the money-quote, from Dalton:

        But Vance Holliday, a University of Arizona archaeologist who has studied Clovis sites for 30 years, found this explanation nonsensical. Such mixing of spherules from different eras could invalidate any conclusion that higher spherule counts represented evidence of a comet impact.

        “I suspect something very odd is going on,” adds Holliday, who also has become a critic of the comet theory.

        After the theory was first announced in 2007 in Acapulco, Mexico, Holliday had attempted to collaborate with Kennett to test the idea. But Kennett effectively blocked publication of the study last year after the results didn’t support the comet theory.

        And those results were blindly analyzed by an independent reviewer selected by Kennett himself. That independent reviewer was none other than Walter Alvarez — an esteemed University of California, Berkeley, geologist and son of Luis Alvarez, the Nobel Prize-winning physicist who first proposed an asteroid struck the Yucatan Peninsula in Mexico about 65 million years ago, wiping out the world’s dinosaurs and most life.

        It was Nic Pinter from whom Dalton got the title-quote, but Holliday’s effort to reach out to the comet-team and the involvement of Walter Alvarez is Dalton’s prize reference.

        The heated rhetoric was toned down, by most parties … since right about this time in mid-2011. Since then, what looks like a careful institutional effort has steadily boxed-in the YDIH, on first one factual point and then another.

        Unfortunately, Dr. Kennett has steadfastly insisted that his premise is valuable & workable … and he repeatedly finds networks of professionals who collaborate with him … which must represent yet-another important backstory … eg, if there was an impact, Native Americans are off the hook for the extinctions, and relationships with them are very important to anthropologists and others.

        Mind you, the overkill-evidence doesn’t quite clear my minimally-convincing bar. My side-bet is, continuing attention to the overkill-hypothesis will steadily weaken it … too.

      • Nasty. Attack dogs all, aren’t we three? Bringing in anything and everything – especially ancient history of Rex Dalton et al.

        All of your stuff you are bringing in is SOOOOOO yesterday – stuff that has LONG since been refuted, rebutted and discarded. You are living in the past, dudes. It’s 2014, not 2009.

        And all of those are just babble. What does Hawks, an anthropologist, got to do with impact science? NOTHING.

        Nic Pinter is a professor at the lowest of the lowuniversity – the super party school of Southern Illinois University, with a prior CV of little but Mississippi River water policy studies – of levees and flood trends. A lot of qualifications there! Nothing on impact science whatsoever or impact materials.

        And what is this “Nic” stuff? Are we being led by the nose, folks? Are we showing our TRUE colors? Are we ACTUALLY hired attack dogs, proxies for Nic” And Vancie boy??

        Yes, we know now why you wouldn’t read ANYTHING about the science of impact materials, of the papers upon papers with lab tests and proper sampling and microstratigraphy.

        You aren’t here to have an open discussion. You were hired to bad-mouth this hypothesis on behalf of the inter-Daulton-Holliday-Meltzer crowd. Aren’t we proud of ourselves for having been thugs?

        TROLLS TROLLS TROLLS…

        Oh, for the shame of it.

        And stupid enough to expose themselves, too.

        YOU ARE OUTED

      • No Mr. Garcia, these are all quality professionals – scientific & journalistic – responding to scientific-community problems that ought to be exposed. The word for this behavior is “whistleblowers”.

        History doesn’t have a “Use By” date. Especially not when it’s still unfolding.

        My most-recent PNAS citation is only months old. I & others laid down major counter-indicative peer-reviewed papers throughout the recent years.

        Real science has a duty to police itself, and that’s what we’re watching. The Younger Dryas Impact Hypothesis is already clearly-identified science-folly. Hopefully, it doesn’t prove to be worse, which is possible.

      • TC: “No Mr. Garcia, these are all quality professionals – scientific & journalistic – responding to scientific-community problems that ought to be exposed. The word for this behavior is “whistleblowers”.”

        IS THERE ANYBODY ON WUWT THAT AGREES WITH THIS SORT OF SCIENCE?

      • WUWT is a science site. Edgar Cayce-ites and dreamy New-Agers need not apply, nor AGW attack dogs, nor lefty projectionists. Good day.

      • Oooh, yeah, are we going to go all AD HOMINEM now?

        Getting all personal?

        Logical fallacy time?

        I love it!

        AD HOMINEM – The last refuge of scoundrels and attack dogs.

        People here at WattsUpWithThat know all about logical fallacies and especially ad hominem attacks. So go for it. It just digs you in deeper.

  61. Steve, I have no dog in this fight but those three really take the biscuit for being mindless attack dogs. That last outburst of vitriol was uncalled for and shows their true colours. That they believe that pouring salt on the mouth of the Amazon will stop it flowing tells anybody all they need to know. They avoided your rebuttal on their stupid claim. They clearly have not read Wunsch. Keep up the good work.

  62. Further, If half a degree is such a global warming catastrophe, how come everything alive today, in all its diversity survived such a ten degree event? The original temperature chart in this post shows just how insignificant so called current warming is.

    If half a degree has catastrophic global impacts, is it too much to imagine that ten degrees was also global and had effect on marginal climates such as Australia, bringing about similar extinctions there, even though remote from the actual cosmic event?

    • “Further, If half a degree is such a global warming catastrophe, how come everything alive today, in all its diversity survived such a ten degree event?”

      EXACTLY.

      “If half a degree has catastrophic global impacts, is it too much to imagine that ten degrees was also global and had effect on marginal climates such as Australia, bringing about similar extinctions there, even though remote from the actual cosmic event?”

      THESE are the kinds of questions to be asking. We do NOT know the answers yet, but people are out there, trying.

  63. WOAH, YEAH! THOUGHT POLICE! Oh, are YOU in the wrong place, making the WRONG WRONG argument, boy.

    When someone thinks he or she has “to police” science – and that HE is the one to do it (shades of WILLIAM CONNOLLEY!), the game is already lost to him. He only is playing politics.

    ON THIS SITE, PEOPLE WHO DECLARE THAT THE SCIENCE IS SETTLED, BOY, ARE YOU IN THE WRONG PLACE AT THE WRONG TIME.

    On WattsUpWithThat, EVIDENCE is what counts.

    All one can do is put their EVIDENCE up, for the world to see. ONCE. Then leave it to the objective world to look at both sides. The objective world does not need police in science. Evidence is what counts. When new evidence comes in – LIKE THIS PAPER – then you get another shot at it.

    And BOTH sides in this have presented evidence, as it has been extracted from the layers of the soil. Both sides are qualified scientists, IN THEIR FIELDS. But regardless of their fields, the evidence doesn’t care. The evidence is the evidence.

    An old adage: Good scientists follow the evidence, wherever it takes them. If someone else can’t follow, that is their own weakness.

    Good attack dogs don’t care about evidence. They care about damaging the people their masters tell them to go bite.

  64. Like the collapse of the Minoan civilisation. They knew it happened but not how. They had destruction on the coast/beach but did not know how it happened. Then after the Asian Tsunami, the sedimentary evidence left beinld, explained it, a coastal tsunami.

    However, a coastal tsunami would not explain the fall, fully. So they looked and dug further. They found Tsunami sediment and wreckage over 100 feet above the beach level. it was huge. Caused major damage to the whole infrastructure, maybe the fleet wiped out (speculation), leaving the survivors open to invasion.

    So, the growing body of evidence for a cosmic event, not necessarily an impact, is growing and as such, so is our understanding of what may have happened. Large graveyards of mega fauna exist along with tsunami muck. Just what you would expect if millions of cubic miles of water suddenly rushed across the land from cosmic melted mile thick ice sheets.

  65. Steve; As per usual you’ve asked the wrong questions (the right ones in reality) about the sacred cow and stirred the bull poop. Good for you! I do enjoy the cross banter when it is open and academic on either side but that last round was something else. I bet you’d make one hell of a lawyer.

  66. Three issues seem apparent here:
    1. Is evidence of a cosmic impact about the time of the Younger Dryas (YD) conclusive?
    2. What caused the extinction of mammoths, saber-toothed tigers, sloths, etc. in the late Pleistocene?
    3. What caused the Younger Dryas.

    Each of these is an independent question that may or may not bear on the other issues. If there was indeed a cosmic event near the YD, that doesn’t prove that it was the cause of the YD nor the cause of extinctions. Many of the discussions above mix these issues. In order for the impact hypothesis to be a credible cause of the YD, it must account for all of the distinctive features of the YD. (Remember Richard Feynman’s and Albert Einstein’s caution that it only takes one negative piece of evidence to kill a hypothesis). Well, take a look at the number and magnitude of well documented YD temperature changes and the duration of the YD (1000 years), which cannot be explained by any single or even multiple cosmic events (there are too many climatic fluctuations over too long a time). These effectively kill the cosmic event hypothesis as a cause of the YD.

    A comment on the temperature fluctuations and the validity of the Greenland ice cores. Be aware that the abrupt warming and cooling of the late Pleistocene was not confined to the YD but began about two thousand years before the YD and well before the postulated cosmic impact event. These earlier temperature fluctuations were as large or larger than those of the YD. These large, abrupt temp fluctuations do not depend only on the ice core evidence. The ice core data is confirmed by well documented advances and retreats of glaciers on a global scale, the CET temp records, and a host of other temp proxies.

    The bottom line remains that you cannot explain the multiple, intense temp fluctuations of the late Pleistocene (YD and older) by cosmic impact.

    .

    • The Older Dryas, Allerod & YD transitions were first identified in lake sediments. The YD requires no ET explanation.

      Your summary is correct. I’d add that there is essentially no compelling evidence of an impact at the YD onset. However, even if there were some evidence such that the Null Hypothesis of totally normal & natural abrupt climate change could reasonably be called into question, it would remain to show how an impact could have caused the YD & the Pleistocene extinctions, which occurred both before & after the start of the YD.

      The YDIH has been effectively falsified. With each passing year, yet more evidence against it accumulates.

    • The use of Quaternary extinctions to justify placing special significance on the cause of the Younger Dryas, could diminish with progress on the former (purportedly an effect of the latter).

      Disease as a factor in extinction could see breakthroughs, as the application of DNA and other molecular methods shifts attention back to this area. That disease could be involved in extinctions is an old suggestion that has lost popularity* … but current events could be a reminder.

      The ages of fossil remains from this die-off are not excessive for biomolecules. Abundant specimens and whole formations have been continuously frozen in the north, with especially good representation of the key affected megafauna themselves.

      (* That half of our children no longer die of endemic communicable diseases, says nothing about what goes on in the wild, much less the Pleistocene. Cervid wasting disease, eg, persists for extended periods – years – in the soils and on the browse-sources of affected populations, and have been shown to remain actively infectious. This single disease could exterminate species regionally, and prevent recolonization.)

      • If this 2012 study has been linked already, I missed it. Please excuse if so:

        http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356666/

        Nanodiamonds and wildfire evidence in the Usselo horizon postdate the Allerød-Younger Dryas boundary

        Annelies van Hoesel, Wim Z. Hoek, […], and Martyn R. Drury

        Abstract

        The controversial Younger Dryas impact hypothesis suggests that at the onset of the Younger Dryas an extraterrestrial impact over North America caused a global catastrophe. The main evidence for this impact—after the other markers proved to be neither reproducible nor consistent with an impact—is the alleged occurrence of several nanodiamond polymorphs, including the proposed presence of lonsdaleite, a shock polymorph of diamond. We examined the Usselo soil horizon at Geldrop-Aalsterhut (The Netherlands), which formed during the Allerød/Early Younger Dryas and would have captured such impact material. Our accelerator mass spectrometry radiocarbon dates of 14 individual charcoal particles are internally consistent and show that wildfires occurred well after the proposed impact. In addition we present evidence for the occurrence of cubic diamond in glass-like carbon. No lonsdaleite was found. The relation of the cubic nanodiamonds to glass-like carbon, which is produced during wildfires, suggests that these nanodiamonds might have formed after, rather than at the onset of, the Younger Dryas. Our analysis thus provides no support for the Younger Dryas impact hypothesis.

      • I believe that is a new reference here, and it is a good one! I read it at the source and saved it. Thanks!

    • You’re right, Dr. E., that proponents of this hypothesis cannot explain late Pleistocene temperature fluctuations by cosmic impact any more than they can the similar sudden swings earlier in that epoch.

      As for extinctions, their temporal and spacial distributions argue strongly for a combination of human predation and climatic effects. Those who advocate climate alone are forced to posit that the Wisconsin glaciation was more “extreme” than the Illinoian or many pre-Illinoisan ice sheet advances, but if anything the evidence suggests just the opposite.

      YD Impact Hypothesis supporters have if anything even less going for them than the Climate Team.

      • You’re right, Dr. E., that proponents of this hypothesis cannot explain late Pleistocene temperature fluctuations by cosmic impact any more than they can the similar sudden swings earlier in that epoch.

        In case you hadn’t noticed, I’ve said that the proponents are dealing with the empirical (real world) evidence in their own order of priorities. The thing that brought this all to their attention was (and is) materials in the black layer (at the very underside of it) that have VERY high spikes – and at that exact time – and which are almost ALWAYS interpreted as indicating an impact. So, they have to continually show three things: The materials are impact-related, there were spikes, and that the spikes were at that time.

        The proponents are dealing with checking that evidence out, over and over, at many sites around the USA, and also in Canada, Mexico, Belgium, and Syria. And that is not even mentioning the evidence in Greenland. None of the other issues matter if the impact evidence (nanodiamonds, etc.) turns out to be faulty. If it is, then it falsifies the hypothesis – which, again, they only came to because of the presence of these materials, those spikes, and THAT time. Had the times been different – as it was for the Carolina bays – they subsequently excluded the particular location(s) the research. As they should. But that did not negate the entire study; the other materials and locations still pointed directly at the YD boundary. And the materials were/are still impact materials.

        So far, there is LOTS of evidence that is NOT turning out to be faulty.

        And what does that mean? The proponents are not prematurely speculating before they have all the evidence. They are focusing on the impact evidence, period.

        But it is clear that AN impact happened at that time, and that its effects reached over an area of 50 million square kms – so it was BIG. Not Tunguska, not Chelyabinsk. Bigger. Why bigger? Black layers exist on all those places I mentioned above. The photos are pretty impressive. Think of 50 million sq kms. Mt St Helens’ ash reached about 22,000 sq kms. (http://www.mountsthelens.com/history-2.html) At Lommel, in Belgium, the black layer is a good 9 inches thick or so in spots. Mt St Helens’s ash was 2 inches at about 300 km away, and then petered out by about 500 kms.

        As for extinctions, their temporal and spacial distributions argue strongly for a combination of human predation and climatic effects. Those who advocate climate alone are forced to posit that the Wisconsin glaciation was more “extreme” than the Illinoisan or many pre-Illinoisan ice sheet advances, but if anything the evidence suggests just the opposite.

        YD Impact Hypothesis supporters have if anything even less going for them than the Climate Team.

        The original overall impact hypothesis stands, minus some things like the Carolina bays. Since that time, the proponents are basically just trying to finish collecting empirical evidence – collecting samples and laboratory testing them. Some of it is really boring stuff. As it should be. They are letting the original hypothesis stand for the present, knowing that some of it is now out. They are not saying much beyond the evidence of an impact.

        But between you and me, first of all, you left out the epidemic hypothesis for the extinctions. So now there are actually FOUR, not three. And people keep publishing papers on the non-impact hypotheses every year. The impact proponents haven’t gotten to the extinctions yet, thought that was part of the original hypothesis and still is. They just have too much work going on with the materials analyses.

        Yes, on a hypothesis this big and complex, at some point some of it may no pan out. It is NOT failing at the present point. Will it fail later on? Possibly. Until the actual science is done, no one knows. They know where the evidence is leading – but it might turn out to be some different effect or accuse, coinciding. Or some combination.

        But right now? Dude, there was an impact. A big one. Those materials don’t get created and spike like that

        Regardless of your opinion and mine and everyone else here, the proponents of all four hypotheses think they are right, and they continue their work.

        Which one you favor (or me) doesn’t matter, you know…LOL

      • YD Impact Hypothesis supporters have if anything even less going for them than the Climate Team.

        Way less. All that “ACC” claims is change, and lo & behold, there is change.

        YDIH has painted itself into a very tight corner. Nothing but cosmic impacts can produce nanodiamond (it’s now made on a normal workbench), and in no other place than a single layer (barring repeat impacts).

        That West guy who isn’t West, and who Kennett still praises, he might be up to something. He had to be locked up in prison for awhile, head-tripping a town he worked for.

        I won’t be surprised to see this thing burn up on reentry itself.

    • Don –

      “Three issues seem apparent here:
      1. Is evidence of a cosmic impact about the time of the Younger Dryas (YD) conclusive?
      2. What caused the extinction of mammoths, saber-toothed tigers, sloths, etc. in the late Pleistocene?
      3. What caused the Younger Dryas.

      Each of these is an independent question that may or may not bear on the other issues. If there was indeed a cosmic event near the YD, that doesn’t prove that it was the cause of the YD nor the cause of extinctions. Many of the discussions above mix these issues. In order for the impact hypothesis to be a credible cause of the YD, it must account for all of the distinctive features of the YD. (Remember Richard Feynman’s and Albert Einstein’s caution that it only takes one negative piece of evidence to kill a hypothesis). Well, take a look at the number and magnitude of well documented YD temperature changes and the duration of the YD (1000 years), which cannot be explained by any single or even multiple cosmic events (there are too many climatic fluctuations over too long a time). These effectively kill the cosmic event hypothesis as a cause of the YD.

      A comment on the temperature fluctuations and the validity of the Greenland ice cores. Be aware that the abrupt warming and cooling of the late Pleistocene was not confined to the YD but began about two thousand years before the YD and well before the postulated cosmic impact event. These earlier temperature fluctuations were as large or larger than those of the YD. These large, abrupt temp fluctuations do not depend only on the ice core evidence. The ice core data is confirmed by well documented advances and retreats of glaciers on a global scale, the CET temp records, and a host of other temp proxies.

      The bottom line remains that you cannot explain the multiple, intense temp fluctuations of the late Pleistocene (YD and older) by cosmic impact. ”

      Now, these are good points of discussion, keeping to the science, to the evidence, keeping to the interpretations of the evidence.

      My personal answers to your questions, to the best of my understanding of the current state of affairs:

      1. Is the evidence conclusive? I can tell you that the scientists involved are doing their best to falsify the hypothesis themselves. They want to attach their efforts to a solid premise, and if it fails somewhere, they will be the first to say so. There are MANY sides to this, and more than probably a dozen lines of evidence, in several fields. That much work isn’t done in a day.

      As Meltzer (skeptic) and Grayson summed up the state of Clovis subsistence hunting in 2002:

      Yet, unlike the discussions of Clovis mobility, there is no consensus as to the nature of Clovis-aged subsistence. In part, this is for the simple reason that the empirical record currently remains inadequate to the task of deciphering subsistence patterns. In addition, however, there is a surprising lack of site-by-site systematic evaluation of the available data that are relevant to subsistence questions [Haynes (1991) is an exception, but he examines only Clovis-age proboscideans, and does not include all such occurrences].

      In other words, the empirical work has to begin somewhere. And nothing can go forward until that is done.

      They are focusing right now on the ones they can test in the lab. Others will have to wait. If the lab results are definitely false, they’re done. But that isn’t happening, so they keep working on it to solidify it – if possible. So far, the lab results on what are normally considered impact markers have consistently come back in the affirmative. But they are not done yet. They keep on finding sites, keep on digging up more micro-stratigraphic samples to test. They are doing due diligence.

      (The skeptics’ attempts to empirically test (replicate) for spikes in impact markers was an inadequate attempt – on three fronts that I can recall. First, they failed to sample in the same location. Then they failed to sample a narrow enough layer, so their wide layer included far too much non–YDB material which watered down their results. Then with spherules it was specifically indicated to examine them with an SM, and they looked instead with optical magnification alone – which was warned against, because the necessary features are simply too small. Yet these protocol failure results were trumpeted as “We didn’t find any, so the whole thing is a farce”. That is the gist of the falsification that failed itself. It is not a replication if the protocols are not followed.)

      Conclusive evidence is down the road – and we all know that even when some people see it as conclusive other ones will interpret some things with different weightings and assert differently. Conclusively in everybody’s minds is not possible, not without a crater and a big stony or iron-nickel ball in the bottom. Don’t forget, people are still arguing over the K-T event, 34 years later – and they even HAVE a crater.

      But the YDIH “team” has done the same sort of empirical tests something like 5 times now, and the skeptics keep posturing in public, pretending that none of the later ones were even done; they point at their original (flawed) replication attempts and publicly even ignore the rebuttals to those attempts. I am not making this stuff up.

      2. Extinction causes? Let me count the ways…

      There are right now four posited causes of the extinction event for the megafauna. (And please don’t forget that there is some evidence that Clovis man himself went extinct at that time – evidence which is itself being debated.) One most of us have heard since about 1980 – Martin’s Overkill hypothesis, which still claims to be IT – the definitive answer. However, climate folks assert that Overkill doesn’t answer enough, and they’ve got their version of things. Then there are those who argue for some sort of epidemic. Those are the Overkill-Chill-Ill hypotheses. And none of them think the other two are correct. Folks here and elsewhere who assert one is triumphant over the other two are stroking themselves and trying to do science by declaration. That is, in my humble opinion. Then 7 years ago along came the impact hypothesis, and all three of those weren’t happy. But those three all had holes in their hypotheses, so the new kid on the block in some ways tried to answer those holes. But the researchers didn’t start out to do any such thing. That just happened in the process of dealing with the evidence.

      So, with FOUR competing hypotheses, the answer to your question is imply that the jury is out, and that none of them has won – or looks like it will win any time soon. Each has what the advocates of the other three think are weaknesses. Pages continue to be put out arguing for each of them.

      3. The cause of the Younger Dryas is up in the air. The climate folks are sure it was the stopping of the oceanic conveyer, from all I can tell. The Overkill folks don’t go into the causes of the YD. I don’t think anyone on the epidemic side of the extinction has anything about the YD cause, but I am probably mistaken. The impact folks see some reason to think the impact fills the gap that the others can’t. I’ve been keeping up with the global warming thing for about 15 years (over half of it here at WUWT, where I am continually impressed by the amount of science going on), and I can tell you that no one dealing directly with that can come up with any forcings intense enough to cause a 13°C or so rise. Their models have all the inputs as close to reality as they can get, and they can barely come up with 4°C, but Mother Nature is having a laugh at their expense, because 4°C by 2100 is looking rather dodgy. I’ve heard various lengths of time for the onset of the YD – some as short as a month or so. (The EXIT from the YD is even more problematic.) Can climate as we know it even DO that? That rapidly? Well, the ice cores seem to show that it HAPPENED, don’t they? So, it seems like either something internal to the system – something very big – came along, something beyond all our knowledge, or something came in from outside – something ALSO beyond our understanding. Everybody is weighting the evidence differently and coming up with different interpretations and speculations.

      Speculating – guessing – is part of the scientific method. Step one, according to Richard Feynman. But after the speculation comes the devising of ways to test the guess out. That is Step 2. Step 3 is to compare the results with what is predicted. No one has succeeded in a successful Step 3 out of the climate side yet.

      The impact people are still in the middle of getting the basic stuff down – what I call the “forensics”. They can go that far for now, and the rest has to come afterward, if that part doesn’t falsify the guess – the impact guess. So far, that part is going well. There is a LOT of forensic evidence. On several lines of evidence. But even after all that is sufficient in their scientific assessment, getting to the WAY that an impact could have created a 1300-year ice age is another story, and will be tackled if and when that is appropriate. No one on the impact side is coming CLOSE to asserting that they won the argument. It is far too early for that. Those impact markers spiking right at the bottom of that black layer keep on being there and passing the lab tests. Bigger picture questions have to wait until the foundation is laid. It is premature to go there. The evidence leads where it leads, but right now every time they come out with a paper the “Daulton gang”, as I call them, screams bloody murder – but then the Daulton gang’s negative papers are full of points that get rebutted. So we re stuck in this he said-she said period of evidence and denial, evidence and denial.

      YES, Einstein and Feynman – I brought them up above myself. And one falsifying SOLID piece of evidence – one FAILURE will surely take down a hypothesis. But with this impact hypothesis having tentacles all over the place, where does such falsifying evidence come from? Debate? Of course not. The proper course of action is to get at the basic science and start doing due diligence at the basic level. Empirical lab results is that level, and that is what they are doing. And you know what? So far the evidence is not falsifying. Which is why Kennett is so verbal about proof, that these lab tests support the hypothesis to a high degree, at the (scanning electron) microsopic level. At the chemistry level. At the materials physics level. If the hypothesis says that such and such markers should be found and pass lab tests, and then those markers are FOUND and DO pass those lab tests, is there a more scientific way to start on this? The big guess – the YDIH – predicts the presence of X, Y, and Z and other markers. If those can’t be shown, the YDIH guys will pack up and go home.

      Not only are they not packing up and tucking their tails between their legs, but more and more other people are coming on board. You don’t hear about it, but it is happening. Sorry if they don’t make a press announcement when each one sides with them, but they aren’t doing it as science by press release.

      You are making arguments at the macro level. Which nI myself love to discuss – but it is not MY research. The YDIH advocates, unlike me, are focusing on the micro level. In general, since the first paper, they have forgone research on the macro level. They chose to go in one direction, the fundamentals first. All of what you argue SEEMS to be true, to you. To me, all your points are arguable – and premature. They will not be prepared to argue or follow up on those aspects until the forensics are convincing to them and to a sufficient number of others. They are pretty accepting that the Daulton Gang will never sign on. But to them the Daulton Gang is yesterday’s news. The Daulton Gang’s attack dogs here keep discussing CON papers from 2009 and 2010 that have long since been rebutted successfully, and which the Daulton Gang and their attack dogs then pretend the rebuttal never happened. They believe that the (rebutted) CON papers are THE last word – and quite frankly, they aren’t. The going over and over of points that have been dealt with is like a yappy dog snapping at one’s ankles instead of an attack dog.

      I will tackle the Greenland ice cores in a separate comment, if you don’t mind. This one is already really long. But it is just my take on it, for discussion purposes. Okay?

      • There is no putative evidence that has not been found riddled with error.

        The YGIH Team just keeps reiterating the same already falsified junk.

        What evidence do you have that North America became depopulated at the YD? You have, no surprise, studiously avoided responding to the hard archaeological evidence that it didn’t, just as you ignore the reality of the overwhelmingly abundant and still mounting evidence against this unsupported conjecture, which can no longer even be dignified with the term “hypothesis”.

    • From the original post:

      Kennett and investigators from 21 universities in six countries investigated nanodiamonds at 32 sites …

      “We conclusively have identified a thin layer over three continents, particularly in North America and Western Europe, that contain a rich assemblage of nanodiamonds, the production of which can be explained only by cosmic impact,” Kennett said. “We have also found YDB glassy and metallic materials formed at temperatures in excess of 2200 degrees Celsius, which could not have resulted from wildfires, volcanism or meteoritic flux, but only from cosmic impact.”

      The necessary conditions are more than met by lightning.

  67. The case for the Cosmic event gets ever stronger and much more detailed. I especially like how team deny use the group pat on the back and self induced blindness as their winning argument.

    • Grey –

      There is no winning and losing, really. The facts of what happened are those facts and no others. We are all flying blind, with maybe 1% of the necessary information. The ones flying LEAST blind are the ones doing the empirical science on this topic – which no one who has posted comments here, including me, has done. (Unless someone is here under an AKA.and hasn’t admitted it.)

      The wise scientist in such a case starts at the beginning – the fundamental evidence – and begins by trying to collect it, measure it, put it into some semblance of order, and then he sees if it leads to more evidence. Premature conjectures on any side are almost certain to lead to wrong scenarios. That includes gradualism when it is a catastrophic event. And it includes catastrophism when it is a gradualist process. Premature includes selecting ONE out of four or more scenarios when not enough evidence has bee collected and collated. It mostly includes thinking that enough evidence is in, when the subject is complex and only 7 years into it.

      One immature thing on the part of the Daulton Gang is that this is so complex that some early conjectures have had to be modified – but the D-Gang keeps on harping no things left behind long ago. The YDB team knew that going in some of it was not going to pan out, but they put it into the first paper, anyway. They thought that those somethings were okay, but the evidence led elsewhere. The Carolina bays was one of those. You don’t find the Carolina bays in more recent papers.

      I think it is maybe premature in 2014 for Kennett to say it’s proven. But it was WAY more premature for anyone to ejaculate in [2009] and 2010 that it was dead as a door nail. Upon reading Kennett’s pronouncement above, I knew WHY he did it – to thumb his nose at the Daulton Gang for their silly early pronouncements.

      Like global warming, we simply do not have enough evidence at this moment. Probably. I only just got hold of the full new paper, so I don’t know the FULL extent of the evidence yet.

      However, one thing is clear: ALL of the “forensic” evidence that exists has been developed empirically by Kennett and that team.*** All the rest is people pontificating based on what they THINK they know and that others – according to them – do not know. I will include myself in that – though, because I HAVE read the YDB team’s papers since 2007, up to this one, I AM at least somewhat informed of empirical evidence that most in these comments here do not know. And if Don Eastbrook is smart, he will read them, too. If he doesn’t, he has no place to comment, because this post is about that paper, when all is said and done. And that paper is additive to the earlier ones.

      This hypothesis is a game changer, if it is true. Those who try to squeeze it [into] the old paradigm are doomed to miss all sorts of things in it and THINK that they are superior because of that non-fit telling them that it is wrong. Without rearranging one’s mind about what the previously known evidence (seen in its older paradigm) CAN mean – in a changed context, all sorts of wrong conclusions will be made. Not CAN be made – WILL be made.

      And since the empircal evidence at the microscopic level is panning out – OVER and OVER and OVER again – the likelihood of this new catastrophic context is becoming more and more likely to be true. Which is WHY people are coming around to it – pretty much one scientist at a time. I say “scientist” and not “geologist” or “astronomer” or “anthropologist” or “archaeologist”, because since 2007 this has ALWAYS been an interdisciplinary hypothesis, covering all of those and more. Every scientist who comes to this has to go OUTSIDE his own specialty in order to capture the entirety of it. And on those other ‘outer’ disciplines for each, he/she starts out mostly ignorant and has to learn new things.

      *** IMHO, people who failed to replicate because they failed to follow spelled-out protocols cannot be considered to have done empirical analysis. In chemistry class, failure to follow protocols gives one a D or an F.

    • Grey –

      Good stuff and a good summary for you – straight from the current paper:

      The proposed impact deposited the YDB layer,which contains many cosmic-impact proxies, including magnetic and glassy impact spherules, iridium, fullerenes, carbon spherules, glass-like carbon, charcoal, and aciniform carbon, a form of soot(Firestone et al. 2007; Wittke et al. 2013). In North America and the Middle East, Bunch et al. (2012) identified YDB melt-glass that formed at high temperatures (1730° to >2200° C), as also reported by three independent groups, Mahaney et al. (2010) in South America and Fayek et al. (2012) and Wu etal. (2013) in North America. This study focuses solely on nanodiamonds (NDs), and so, for independent discussions of other proxies, see Haynes et al. (2010) and Paquay et al. (2009), who found no evidence for the platinum-group elements iridium or osmium. Alternately, Wu et al.(2013) found large YDB anomalies in osmium, as discussed below. Also, in a Greenland ice core, Petaev et al. (2013) found a large YDB abundance peak in the platinum-group element platinum. Surovell et al. (2009) found no YDB peaks in magnetic spherules, whereas LeCompte et al. (2012) found large, well-defined YDB spherule peaks at sites common to the study by Surovell et al. Also, critical overviews of the YDB hypothesis are presented in Pinter et al. (2011) and Boslough et al. (2012). Recently, the YDB cosmic impact was independently confirmed by Petaev et al. (2013), who re-ported compelling evidence from a well-dated Greenland Ice Core Project (GISP2) ice core exhibiting a sharp abundance peak in platinum precisely at the YD onset (12,877 ± 3.4 cal BP). Those authors’ mass-balance calculations indicate that the platinum peak resulted from a major cosmic-impact event by an impactor estimated to be at least 1 km in diameter. Similarly, Wittke et al.(2013) estimated that the tonnage of YDB ejecta (spherules and melt-glass) is comparable to that ejected from the 10.5-km-wide Bosumtwi Crater, likely produced by a 1-km-wide impactor. The GISP2 platinum peak is coeval with the abrupt on-set (≈1.5 yr) of the atmospheric changes that mark the YD climatic episode in the North Greenland Ice Core Project (NGRIP) ice core at 12,896 cal BP (Steffensen et al. 2008). The discovery of such an unequivocal impact proxy at the YD onset in the Greenland record was predicted by the YDB impact hypothesis when it was initially introduced (Firestone et al. 2007). The comprehensive impact proxy assemblage in the YDB layer also includes NDs and diamond-like carbon, which were discovered within carbon spherules, glass-like carbon, and bulk sediment.

      How is that for a fair presentation – even mentioning the skeptical papers?

      I would draw attention to the NGRIP ice core – where it actually has the platinum peak and the start of the YD right there at the same point in the ice layers. And that this is exactly what Firestone predicted 7 years ago in his paper that started all this.

      The important thing about all their evidence is three-fold:

      1. The impact materials
      2. The spikes right at the underside of the black layer
      3. The carbon dates keep on pointing to 12,800 years ago.

      What the impact did is for people to determine later. First they have to show strong enough evidence of an impact AT THAT TIME. It doesn’t matter for no what else the ice cores show. The first order of business is to not screw up the impact evidence, to get it solid as hell.

      BTW, if you want to read how this all started, Firestone wrote a book called “The Cycle of Cosmic Catastrophes.” It is available on Amazon.com. It is a very good science book. He just wanted to find out why there was a bump in the Carbon14 calibration curve.

      • Typo – should read ” It doesn’t matter for now what else the ice cores show.”

        The reason I say that is that they need to keep their sights on doing things in proper order. The ice core stuff will still be there later and they will have to deal with it then. Now is not the time.

  68. @Don Easterbrook 8:47am:
    “A comment on the temperature fluctuations and the validity of the Greenland ice cores. Be aware that the abrupt warming and cooling of the late Pleistocene was not confined to the YD but began about two thousand years before the YD and well before the postulated cosmic impact event. These earlier temperature fluctuations were as large or larger than those of the YD. These large, abrupt temp fluctuations do not depend only on the ice core evidence. The ice core data is confirmed by well documented advances and retreats of glaciers on a global scale, the CET temp records, and a host of other temp proxies.

    The bottom line remains that you cannot explain the multiple, intense temp fluctuations of the late Pleistocene (YD and older) by cosmic impact. ”

    Don,

    No one can have been involved with this for even three weeks without being aware of the abrupt warming and cooling in the very end of the Pleistocene.

    I’ve already stated here that if the YDIH is “forensically” shown to have happened, then I agree that they are going to have to try to explain those other severe warmings and coolings. ESPECIALLY, IMHO, the warming at the end of the YD. All of those are as clear as the nose on ones’ face.

    But all of that is putting the cart ahead of the horse. They are in the stage of empirical evidence collecting, measuring, and collating. THAT evidence says an impact happened. To assess WHERE that impact can fit into an overall scenario – that step comes later, if the forensics keep on saying “Impact materials – SPIKE – AT THE YDB”.

    These people are not STUPID. They are not sophomores in high school. Some are eminent in their fields – Goodyear, Anderson, West, Firestone, Schultz, and sometimes Vance Haynes. With your PhD you should be discussing this all with THEM, not hanging around WUWT and trying to educate me.

    The facts of this WHOLE things are this: SOME researchers and others think this has legs. SOME OTHERS don’t. It is obvious that if they disagree on this that it is

    1. Not settled science
    2. Supported by at least SOME of the evidence, never mind your opinion and mine.
    3. Up to those researching it to proceed?
    4. Up to their skeptics then to examine and TEST their measurements, yes?

    It is NO the skeptics’ place to pontificate on their own feelings about it, but to TEST the results. PER the specified protocols. And if they disagree with the protocols, THEN is the time to challenge the methodology.

    All this here is blather. If you disagree with their methods, take it up with them.

  69. The wrap-up the original post says …

    “The evidence we present settles the debate about the existence of abundant YDB nanodiamonds,” Kennett said. …

    Settles the debate?! D’oh!

    … “Our hypothesis challenges some existing paradigms [names most sciences known to humankind] …” Kennett said.

    Well their hypothesis might challenge the sun and the moon and the stars, but Walter Alvarez, who knows a thing or two about tweaking paradigm-noses, figured their data … supported nothing.

    So of course, they got rid of him.

  70. Steve,

    Threadbombing, name-calling, upper case shouting, none of these will win a scientific argument. Neither will talk of attack dogs (not to mention revenge of the attack chickens).

    One of the hardest things in science is the ability to remain open minded about a hypothesis even after having invested much time and effort supporting it. Die-hard clinging to a hypothesis wont make it any more true or false.

    Many AGW warmists are going to have to learn this painful lesson in the years ahead, it is good if we at WUWT can give them some leadership by example with this.

    At the end of the day, there are two essential positions in the climate debate. You may be surprised to learn your position is on the side of the AGW warmists. These two positions are:
    (1) The “static” climate position (or the Gavin Schmidt position or the AGW missionary position): climate by itself is static, passive and peacefully at equilibrium (like the brains of those who hold this absurd position) and climate CHANGE – a shocking and scandalous anomaly – can only come from an external forcing agent – and it is in your interest financially and politically for this agent to always be man-made;

    From the static position if you see a climate change you can complacently jump immediately to the conclusion of human interference with climate.

    (2) The “dynamic” climate position (the scientific position): climate as a dissipative nonlinear heat engine is never anywhere near equilibrium, it possesses internal dynamics driven primarily by ocean circulation patterns which can oscillate chaotically and thus variation over many timescales is the expected norm.

    From the dynamic position if you see climate change you conclude nothing about any external forcing since your evidence for external forcing needs to be exceedingly strong, in the context of continual natural and normal internally driven climate variation.

    Now WUWT is an anti-AGW web site in its overall stance. However many who post here, including Steven Garcia, but also the “peleton” of cyclists arguing for driving of climate by solar cycles, planetary orbital cycles, bolide impacts etc. These scientists are by and large opposed to AGW but their position is essentially the static position since they argue that climate must be forced from outside in order to change. So this position is in fact close to those who argue that only CO2 can change climate.

    The alternative position to this is the dynamic position which will eventually be shown to be the correct position, since all that needs to be known about how the ocean can drive climate fluctuations over decades, centuries and millenia has been already well understood for many years.

    The eventual general acceptance of the dynamic climate position will be slow but inevitable, it will depend on whether scientists holding the static position can honestly confront the evidence and understand the nonlinear thermodynamics underlying ocean driven climate dynamics, and have the inner strength to turn away from the useless and false static position even if they have invested much time and energy – even entire careers – in the static error. Or if they will just have to slowly die off to unbind the truth for future generations.

    • What “drives” climate on the scale of tens to hundreds of thousands of years is well established, ie Milankovitch Cycles. IMO orbital and rotational effects also influence climate shorter term, on the scale of hundreds to thousands of years, at least, and possibly decades.

      On our water planet, ocean oscillations are also important, but are not totally sui generis. Changes in solar irradiance play a demonstrably large role (as modulated by orbital and rotational mechanics), especially UV, and solar magnetism as well.

  71. Steve,

    There is no evidence dispositive of an impact, hence no reason other than blind faith for imagining that one happened at the YD.

    The paper discussed in this post simply rehashes the same material already thoroughly debunked since 2007 when this cockamamie hypothesis was first hatched. The YDIH Team has its true believers, or trough-feeding rent-seekers, just as does the Catastrophic Man-Made Climate Change Team. No amount of actual evidence can or will dissuade them.

    Your ranting and raving only shows how weak your case is. By “weak”, I mean “non-existent”.

  72. The pack attack, the appeal to authority and the bellicose false accusations. Boy are these guys afraid.

    Most prob the same mob that denied the Missoula flood, plate tectonics and the Atkins Diet.

    “There is no evidence of an impact” denial and false argument all rolled into one cheap shot

    • You & Steve are clearly projecting. If indeed you & Steve are two separate individuals.

      There is no evidence of an impact. Evidence has to be reproducible. No one but the Team finds any evidence of an impact. All independent studies have shown their supposed “evidence” non-existent, including that conducted by Dr. Alvarez, the author of the K/T impact hypothesis, now a well-supported theory.

      You’ve even adopted the CACA Team’s language & character assassination. It’s ludicrous to compare the existence-free YDIH with the Bretz Floods (apparently you’re unaware that there were many, not just one) & plate tectonics.

      You’ve got nothing. Nada. Zilch. Zip.

    • There is no “pack attack” There is just the recognition by scientifically literate commenters that this “hypothesis” is yet another crock masquerading as science.

  73. The bottom line remains that you cannot explain the multiple, intense temp fluctuations of the late Pleistocene (YD and older) by cosmic impact.

    .
    Don Easterbrook says which is correct. Cosmic impact is not the cause of the YD a much more realistic cause was the ice dynamics at that time and the initial state of the climate which was near the threshold of glacial versus inter – glacial conditions which made the climate especially vulnerable to changes in solar variability due to primary solar changes and the associated secondary effects. Also at that time the earth’s magnetic field was very weak and under going excursions which made it quite vulnerable to cosmic ray concentrations changes which would be associated with weak solar conditions which evidence points to.

    Further the YD event was by no means an isolated or unique event which throws cold water on a comic impact.

  74. USGS on the 2012 black mat study finds YGIH myth busted:

    http://www.usgs.gov/newsroom/article.asp?ID=3180&from=rss#.VAZm36NuowQ

    Evidence used to support a possible extraterrestrial impact event is likely the result of natural processes, according to a new collaborative study led by U.S. Geological Survey scientists.

    Elevated levels of iridium, magnetic spherules, and titanomagnetite grains, collectively called “impact markers,” form the bulk of the evidence for the Younger Dryas impact hypothesis, a hotly contested idea that links climate change, extinctions, and the demise of the Clovis culture.

    Scientists found high levels of the reported markers in deposits called black mats, the organic-rich remains of old marshes and swamps, at several sites in the southwestern U.S. and the Atacama Desert of northern Chile. Markers were found in black mats ranging in age from 6,000 to more than 40,000 years in areas far removed from the purported impact location. These findings indicate the markers accumulated naturally in wetlands and are not the result of a catastrophic impact event. The full report is available online.

    “Luis and Walter Alvarez’s proposal that an extraterrestrial impact was responsible for extinctions at the Cretaceous-Tertiary boundary eventually moved from unlikely hypothesis to accepted theory, and with its acceptance came the temptation to apply this explanation to any rapid change in Earth’s conditions,” said USGS Director Marcia McNutt. “The results of this study demonstrate the importance of maintaining a healthy skepticism and multiple working hypotheses.”

    The controversial Younger Dryas impact hypothesis contends that an extraterrestrial object, possibly a comet, exploded over North America about 12,900 years ago, resulting in dramatic climate change, massive wildfires, and the extinction of many large herbivores and their predators. If true, the recency of such a large impact might have implied a greater risk to humanity than previously imagined.

    “When the idea was first promoted in 2007, those of us familiar with black mats suspected that normal depositional processes in wetlands might be responsible,” said Dr. Jeff Pigati, a USGS geologist and lead investigator of the new study. Indeed, this is what Pigati and coauthors now report in this week’s issue of Proceedings of the National Academy of Sciences, USA.

    “This is a great object lesson for how scientific hypotheses are done and undone,” said Paul Baker, Professor of Earth and Ocean Sciences at Duke University and a member of National Geographic Society’s Committee for Research and Exploration.

    The study was funded cooperatively by the National Geographic Society, the USGS, the Millennium Science Initiative and Chile’s National Commission on Scientific Research and Technology.

    • Nice page for this study, on USGS.

      It’s interesting to see that National Geographic funded it. They often run with ‘pop stories’, and YDIH still gets strong ‘gee-wiz’ coverage in the commercial press, even while the studies that show negative findings are panned.

      It’s worth noting, that nobody likes an exciting cosmic-impact story any better than all those reporting here on the hard-science negations, nor indeed the authors & institutions of those published papers. I do not doubt that Hollywood has been sniffing around quite seriously.

      Public interest in this general sort of thing is so strong, there has in fact been a steady string of decently-successful movies on photogenic wow-wee science-stories … and this YDIH could be a doozy.

      But it has to be “based on Science“, to get cooperation from real scientists and academic and government science institutions. That they won’t touch it is in itself a clear sign that the science says “nah”.

      This whole affair has had so many “odd” aspects to it … the knowledge eg that these “black matts” are usually wetland layers, or fluvial deposits (they are very common along the Quaternary bluffs lining the shores of the Olympic Peninsula/Pacific Northwest where I live … I’ve explored & sampled them for many decades) … how could the project leaders pose these layers as conflagration-deposits … these starkly-black layers draw notice & attention, and thus are popular study-specimens. They’re strikingly black, but they aren’t fire-remains. Strange.

  75. It never ceases to amaze me, how the blind circle the wagons, use circular logic and false assertions along with a liberal dose of defamation and insult to protect an untenable position.

    They are the same ones who cry foul when the watermelons use such tactics. But just the same as watermelons they ignore all evidence to the contrary of their deluded dreams and roll on like an extinct mammoth across the pages of blogs, acting just like a lost herd.

    Their evidence, wow, temperatures changed suddenly before. Thats it.

    Any attempt at debate or discussion or comparison, shouted down by the group think.

    They really need to look at WUWT ethos and look in the mirror.

    • Your position is untenable. There is no valid evidence of an impact, no mechanism by which the nonexistent impact could have caused the YD and no way in which the impact could have caused whatever extinctions might have occurred promptly after the onset of the YD.

      That sharp warmings and coolings occurred before in the record is prima facie evidence that your position fails totally to show false the Null Hypothesis. If the YD was nothing special, and it wasn’t, then there is no reason to suppose an imaginary impact to explain the abrupt climate shift or the subsequent and preceding extinctions.

    • Grey, I haven’t abandoned you. I just know when pearls are exposed to swine…

      “They are the same ones who cry foul when the watermelons use such tactics. But just the same as watermelons they ignore all evidence to the contrary of their deluded dreams and roll on like an extinct mammoth across the pages of blogs, acting just like a lost herd.

      Their evidence, wow, temperatures changed suddenly before. That’s it.”

      Bingo. It’s like in a trial and the jury is done hearing the prosecutions,case, and someone declares the accused guilty – before hearing one word from the defense counsel’s case. The one loudmouth shill in the jury shouting at the top of his lungs, “We don’t need to hear no other Side! He’s GUILTY!”

  76. Sturgis continues to flail.

    Here is more evidence, it needs investigation and study to increase our knowledge, not hand waving.

    http://www.livescience.com/30896-stalagmites-climate-clues-blue-holes.html

    The YD African dust storm was a major event and resulted in great ecologi8cal changes in the Bahamas. But what caused the event.

    Previous sudden changes could also have been caused by similar events. we know the dinosaur extinction was one such.

    Why do you ignore that the massive changes recorded make a mockery of catastrophic climate changes now being peddled to extort money and fear from you?

    Why do you continue to insult?

    What are you afraid of?

    Saying that it happened before does not explain why or how at all.

    • Grey Lensman said @September 2, 2014 at 10:01 pm

      The YD African dust storm was a major event and resulted in great ecologi8cal changes in the Bahamas. But what caused the event.

      Lensman’s reference describes the time frame of their study:

      The stalagmite samples from the Great Blue Hole showed three periods of rapid shifts from a wet to dry climate … so-called Heinrich events … during the period from 13,500 to 31,500 years ago.

      What they were looking at happened before the Younger Dryas, and spanned 18,000 years.

      The mention of African dust is:

      Curiously, the team also found high levels of iron in the stalagmites during the Heinrich events. Iron shouldn’t be there since there are no known nearby sources. The team’s theory is that the iron was blown in during dust storms that originated in West Africa, Arienzo said.

      During the period of the Heinrich events, great dust-storms blew south from the terminus of the North American ice-sheet, transporting vast deposits of soil hundreds of miles across the future United States. These blows would carry more dust & iron to the Bahamas, than dust-storms from Africa.

      Certainly interesting work by U Maimi with the Blue Hole stalagmites, even if it’s not about the Younger Dryas.

  77. Impact, you keep repeating impact. As has been said many many times, no actual impact is required, just an air burst.

    • I’m concerned that yet more pseudoscience is being perpetrated.

      It’s called the YD Impact Hypothesis because one of the various versions of the baseless conjecture has a comet actually hitting the Laurentide Ice Sheet. You really ought to read up on the nonsense you purport to support. Besides which even a low airburst which leaves a crater or impact area counts as an impact.

      The opening paragraph of the UCSB press release repeats more falsehoods:

      “Most of North America’s megafauna — mastodons, short-faced bears, giant ground sloths, saber-toothed cats and American camels and horses — disappeared close to 13,000 years ago at the end of the Pleistocene period. The cause of this massive extinction has long been debated by scientists who, until recently, could only speculate as to why.”

      This baseless assertion is blatantly false on its face. Mastodons lived for millennia longer; giant sloths for 6000 years or more after 13 Ka. DNA evidence shows that horses and mammoths both survived at least thousands of years later than their last appearance in the North American fossil record.

      http://www.pnas.org/content/106/52/22352.full

      There were probably other refugia for mammoths in Beringia besides the area of St. Paul Island. And of course mammoths survived until less than 4000 years ago on Wrangel Island, off eastern Siberia.

      There is nothing special about the YD that didn’t happen at prior glacial-interglacial transitions, so no need to posit an ET event. There is no valid evidence for such an event, as every independent analysis has shown, including by the author of the well validated K/T hypothesis, who himself also allows that other causes contributed to the demise of the non-avian dinosaurs besides the Yucatan impact. There is no plausible mechanism for an imaginary ET event to have caused the totally natural YD climatic fluctuation. There is no evidence that “most” North American, let alone Eurasian, megafauna went extinct at the YD boundary. Indeed the more evidence accumulates, it appears that many of the species previously assumed to have been wiped out then died off before or long after the YD.

      This completely conjectural “hypothesis” has nothing going for it. Nothing at all.

      • Your heroes’ press release calls it an impact. Please get your bedtime story or fable straight:

        http://www.sciencedaily.com/releases/2014/08/140827163443.htm

        Nanodiamonds are forever: Did comet collision leave layer of nanodiamonds across Earth?
        Date:
        August 27, 2014
        Source:
        University of California – Santa Barbara
        Summary:
        A comet collision with Earth caused abrupt environmental stress and degradation that contributed to the extinction of most large animal species then inhabiting the Americas, a group of scientists suggests. The catastrophic impact and the subsequent climate change also led to the disappearance of the prehistoric Clovis culture, and to human population decline. Now focus has turned to the character and distribution of nanodiamonds, one type of material produced during such an extraterrestrial collision. The researchers found an abundance of these tiny diamonds distributed over 50 million square kilometers across the Northern Hemisphere.

    • Grey –

      On that particular point, I will say that I disagree with you. I can be wrong on it, but I am pretty convinced by Tunguska and Chelyabinsk that – Boslough’s work aside – an airburst is not sufficient. That is just my own take on things at this time. Chelyabinsk really taught me quite a bit. About ablation, about the amount of psi, about how deep into the atmosphere an object can get before the stresses prevent it from staying together long enough to hit the ground. But right now I also am strongly leaning toward the idea that almost all entry paths are low angle. Chelyabinsk was at about 20°. EVERY bolide I’ve seen has been low angle. Until I see a high angle entry, I am leaning that way. Ablation ate up about 90% of the mass of the Chelyabinsk object before it flared – and then only about 1 meter was left out of a 17-meter object. I think that other than the size, Tunguska and Chelyabinsk wee very much the same. Tunguska – because of its size (IMHO at this point) – was able to penetrate deeper (closer to the ground), so the amplitude of the shock from its flare was more intense at the surface.

      That is my own working premise for now. Subject to alteration with new evidence.

      I think that to put enough energy into the atmosphere to ignite the conflagration on that wide of a scale the event needed to be an impact. And no, we don’t have a crater.

      But Luis and Walter Alvarez’s crater took 10 years to find. And had those two counted on academic scientists to find their crater, they might STILL be looking. Chixculub was only found because a perceptive oil industry field geologist became aware that people were looking for a crater.

      The YDB hypothesis has only been around for 7 years, and the object envisioned is much smaller than the K-T impactor. Not only that, but right now the “impact specialist community” only looks at one kind of impact evidence – ones that look like Barringer Crater, made by clear cut stony or iron/nickel asteroids-turned-meteorites. But with the density range of about, say 0.25 g cm^-2 to about 3 or 4 g cm^-2, the variation may deliver something quite unrecognizable if people are looking for Barringer everywhere. What those impacts of low density-high velocity comets might look like, no one has a CLUE.

      I invite you also to look at something called the Rio Cuarto craters. Google that and take a look at what ARE considered craters – in spite of the conservatives arguing otherwise! – down in Argentina, on the pampas. VERY big and VERY elongated craters – and QUITE deep. VERY much different. Very low angle impacts. On Google Earth, also pan SSW of the recognize ones NNE of the city of Rio Cuarto. Some of those craters are several miles long, and as I said quite elongated. Not Barringer at all.

      We have found about 1400 Near Earth Objects (NEOs), using – FINALLY – satellites to get a clearer view of the space around Earth’s orbit. Only a very few percent are we currently aware of – mostly Apollos and Atens. None of the ones we know about are in orbits threatening us in the next several decades. But, as Chelyabinsk showed us, we can get blindsided at just about any time. NOBODY saw Chelyabinsk’s meteor coming at all.

      A good deal of the interest in the YDB is at least peripherally about our current and future risk from such objects that might come out of nowhere.

      Tunguska’s object came out of the Sun, in the early morning, just like Chelyabinsk did. It came in on June 30th, 1908. Tunguska, however, came right at the perfect time of the year to have been a Taurid comet/meteor. The Taurids are remnants of the very large comet which spawned the comet Encke (google “Encke Napier Clube”). That big one is referred to as the “Encke progenitor”. It is calculated to have been about 30 km across (shoot me if I don’t recall that precisely correct). Encke itself is only a very small percentage of that mass, so the smaller fragments are mostly still buzzing us annually – producing the Taurid meteor shower around the end of June every year. And that is exactly the time of year when the Tunguska object came down. Because of the differences in orbits – using Earth vs Encke as a guide – and the pertinent velocities, we see a different part of the Taurids every time they adorn our night skies. 90%+ of the mass of the Encke progentior is probably still out there W(We can’t know for sure), and some of the fragments are in all likelihood as big as the big fragments of Shoemaker-Levy 9 which smacked into Jupiter 20 years and about 6 weeks ago. (We need to use Encke as a guide because there are so many tiny fragments that none of them are able to be tagged/identified and tracked.)

      The reason we don’t know how much of the Encke progenitor is still out there is because some of them may have already smacked Earth in the 30,000 years or so since it broke up. Whatever hasn’t hit us yet is a good candidate to hit us in the future.

      So, basically, the reason we need to identify things that hit Earth in the past is to get an idea what kind of risk we are under. If all this was ancient history and that is all, nobody would give a damn, really. But since objects DO come at us out mof nowhere, we need to assess what our risk is and hopefully that risk is low.

      To hear the Gradualists tell it, Earth hasn’t been hit by anything we need to worry about in a VERY long time – hundreds of thousands of years. But not long ago at all, that value was several MILLIONS of years. As times has gone by with new and better information, that time between Earth impacts has ALWAYS gone down, not up. At the present we don’t even know for sure if the timing we have is correct or will continue to get smaller.

      The real truth right now is that if a 1-km object was coming at us,

      1. It is 90% that we don’t know about it yet
      2. Even if we see it coming, we don’t have the capacity to divert it or destroy it. We KIND OF have some capabilities – but all of those are maybes.
      3. We can pretty much kiss our collective arses goodbye – because
      4. The three 1-km+ fragments of Shoemaker-Levy 9 that hit Jupiter in 1994 created plumes LARGER THAN THE PLANET EARTH, even in the heavier gravity of Jupiter. Which means
      5. That such impacts on Earth would have even LARGER plumes.

      J. Hills and M.P. Goda calculated long ago that if a 300-m iron meteor hits in the OCEAN – not even on land, mind you – the coastlines 1000-km away will see a tsunami with run-up of about 1.7 km (more than 1 mile high)..

      Working with Peter Leonard determined that

      “Impacting asteroids greater than 100-meters in diameter, which is near the minimum size that produces significant local damage, appear as stars of at least visual magnitude 18 during their final 10 days to impact unless they approach earth from the vicinity of the sun in the sky.”

      So, we would have all of 10 days warning.

      But we don’t need to worry. After all, we have the attack dogs to police our thinking and to inform us of everything we need to know, and diverting and harassing the FEW people who are trying to assess an earlier impact possibility. The harassers are trying to make sure no one takes any of this seriously – telling us the THE SCIENCE IS SETTLED – that those who are researching all of this are a bunch of stumble-bums that can’t read a ruler or a lab report properly.

      But the science is not settled at all. Where those harassers are trying to convince people on WUWT that their side is the only side to this, some sober and serious scientists are slowly coming to realize there is something there – that the lab tests don’t lie, and that this is something to look VERY seriously at..

      Now what effect any of this has, relative to the ice core readings (which seems to be the only bullet in the opposition’s rifle) – and which will be dealt with in its turn, is this: We do not know what our risk is. And yet, HOW many objects coming out of nowhere have set off the NORAD alerts?

      Some people seem to think this is an acceptable risk situation – that we shouldn’t look into our past and do the best science we have to ascertain our risk level. Personally, I am not one of the ostriches. I’d rather tackle this on both fronts – look for objects “out there”, and also look into our past.

      I have NO idea why anyone would think that these are not worth doing. BOTH.

      No one is suggesting a global-warming-like panic. There is time to look at this calmly and patiently. And if the risk is non-existent, we can all go back to living our lives.

      But if we don’t at least assess both ends of this risk – aren’t we kind of really, REALLY stupid? The joke about the ostrich is always that his arse is still sticking out. And that he may not get to kiss it goodbye.

    • Oh, and Grey, take much of what this yokel is saying about pseudoscience with a grain of sand.

      Be aware that science new articles are basically “Science for Dummies” articles.

      An important Rule of Thumb: Always go to the source for your information – never to popular articles. Otherwise, we should all go to the Daily Mail or the St Louis Post Dispatch to learn our science.

      In this day and age, we don’t need journalists summarizing and paraphrasing for us.

      I recommend Google Scholar. Often you only get Abstracts, I admit, which are the scientist’s summaries. But should you use THEIR summaries in their own words, or some journalist’s summaries? Guys who are scared for their jobs, since the internet let’s people go straight to the source and news organizations are all on their last legs and hyperventilating about how to keep their jobs. And that leads to sensationalizing a LOT of what they write.

      What you will often enough find is that the popular articles exaggerate – especially in their headlines. And even when they aren’t – how can you be expected to know the difference? You don’t.

      So, go straight to the source. I promise – it will not be as much over your head as you may think. You will understand it every bit as well as that journalist. Trust me on that.

      And TRUST BUT VERIFY.

  78. Oh, and Grey – in case you need it spelled out for you:

    There ARE two sides to this.

    Two sides – regardless of what the thought police are trying to shove down your throat – and the throat of everyone here at WUWT.

    Go inform yourself. Then make up your own mind.

    Hey, my side MAY be wrong. So far the lab tests don’t say so, but maybe some empirical evidence down the road will falsify all of this. THAT is what the scientific method is all about — not some yayhoos getting all shrill on a blog.

    Remember – the scientists will figure this out.

    That’s what we pay them the big bucks for… LOL

  79. I was looking for the Bahamas source for a while to check it. The experts could easily calculate the winds required to transport that dust that far.

    Agree about the two sides, but its sad when one clearly steps way out of line.

    For what its worth, reading what they say, does not convince me that they have a real answer. The cosmic event makes sense but is not yet totally proven but time will tell.

    • Exactly. It has some evidence pointing that way, and they have the right to pursue it. Which they are doing.

      It is QUITE obvious that some people won’t buy it, even if a meteor and crater are found. Some people have no capacity to admit being wrong. So what if they don’t? As in other science developments, the wrong ones eventually will die off and the next generation will treat them like they do the now forgotten people who locked up Galileo and threatened Copernicus so much he had to publish after his death.

      There is opposition to every development in science. “NO! NO! Please don’t change anything I learned in junior high!”

      • Who are these people whom you imagine would not be convinced by a crater? At the K/T boundary, there was not only clear evidence of an impact but eventually a crater found.

        Your delusions are paranoid.

        Those who object to this baseless conjecture do so on the basis of science, ie evidence, for which there is none to support this assertion, and all the evidence in the world against it.

  80. Sockpuppet at Wikipedia:

    A sockpuppet is an online identity used for purposes of deception. The term, a reference to the manipulation of a simple hand puppet made from a sock, originally referred to a false identity assumed by a member of an Internet community who spoke to, or about, themselves while pretending to be another person.[1] The term now includes other misleading uses of online identities, such as those created to praise, defend or support a person or organization …

    In the WUWT Policy page (under About):

    Trolls, flame-bait, personal attacks, thread-jacking, sockpuppetry, name-calling such as “denialist,” “denier,” and other detritus that add nothing to further the discussion may get deleted; also posts repeatedly linking to a particular blog, or attempting to dominate a thread by excessive postings may get deleted.

    Steve Garcia and Grey Lensman sound like the same person.

  81. Ah yes, meteors that specialize in big game, climate change that specializes in big game, disease that specializes in big game, dogs and dire wolves that specialize in big game, versus hunters that specialize in big game. To think that such a question could drag on for decades. –AGF

  82. I find this complete insistence “There must be a crater” amusing.

    The vast majority of Earth impacts have left no trace as they are atmospheric or water impacts.

    Water impacts include ice. As for example, the impact/fireball in Greenland in 1997 that the USAF DSP satellites picked up and classed as “The peak radiated intensity recorded on this event was 9.5E10 watts/sr” and “the total radiated energy of the event was 2.7E11 Joules” AKA roughly a 100 kiloton nuclear detonation equivalent.

    See:

    http://meteor.uwo.ca/research/fireball/usaf/usaf982.txt

    A large cluster of smaller bodies of the Tunguska and Chelyabinsk level could apply heat and blast waves over a huge continent sized area and leave zip, zero, nada in the way of recognizable over 12K(+) years craters. The supply of dead plant mass left over would be the basis for large scale forest fires started by things like lightning.

    This neatly gets around a number of energy budget issues people have challenged the YDB hypothesis with.

    Now, if you want to talk science, as opposed to argumentum ad nauseam, see this recent YDB impact paper abstract and look closely at _what else_ is showing up with hexagonal nanodiamonds —

    Nanodiamond-Rich Layer across Three Continents Consistent with Major Cosmic Impact at 12,800 Cal BP

    http://www.jstor.org/stable/10.1086/677046

    “Abstract
    A major cosmic-impact event has been proposed at the onset of the Younger Dryas (YD) cooling episode at ≈12,800 ± 150 years before present, forming the YD Boundary (YDB) layer, distributed over >50 million km2 on four continents. In 24 dated stratigraphic sections in 10 countries of the Northern Hemisphere, the YDB layer contains a clearly defined abundance peak in nanodiamonds (NDs), a major cosmic-impact proxy. Observed ND polytypes include cubic diamonds, lonsdaleite-like crystals, and diamond-like carbon nanoparticles, called n-diamond and i-carbon. The ND abundances in bulk YDB sediments ranged up to ≈500 ppb (mean: 200 ppb) and that in carbon spherules up to ≈3700 ppb (mean: ≈750 ppb); 138 of 205 sediment samples (67%) contained no detectable NDs. Isotopic evidence indicates that YDB NDs were produced from terrestrial carbon, as with other impact diamonds, and were not derived from the impactor itself. The YDB layer is also marked by abundance peaks in other impact-related proxies, including cosmic-impact spherules, carbon spherules (some containing NDs), iridium, osmium, platinum, charcoal, aciniform carbon (soot), and high-temperature melt-glass. This contribution reviews the debate about the presence, abundance, and origin of the concentration peak in YDB NDs. 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. The large body of evidence now obtained about YDB NDs is strongly consistent with an origin by cosmic impact at ≈12,800 cal BP and is inconsistent with formation of YDB NDs by natural terrestrial processes, including wildfires, anthropogenesis, and/or influx of cosmic dust.”

    The “CSI” for the YDB hypothesis is very strong — its more than just nanodiamonds — and thus far I have seen very little, other than outdated or flawed papers by the ‘usual suspects,’ challenging it on the basis of sound science.

    • There are lots of craters on the ocean floor and under other bodies of water.

      Also, your arithmetic is wrong by orders of magnitude: 2.7E11 joules equals 0.06 KT, ie 60 TNT tons equivalent. The proposed YD “impact” would have been at least eight billion times more energetic than the puny strike you cite. Benson doesn’t know if even 474,000 megatons would have done it:

      http://www.realclimate.org/index.php/archives/2009/01/the-younger-dryas-comet-impact-hypothesis-gem-of-an-idea-or-fools-gold/comment-page-1/#comment-108750

      Somehow it escaped your notice that the paper you linked is the same one which is the subject of this blog post.

      Every single one of the alleged evidences of an impact has been repeatedly thoroughly debunked by real scientists. Studies doing so are linked in the comments above.

      So far from being “strong”, there is essentially no evidence in support of this falsified hypothesis, if a baseless conjecture can be so dignified.

      • It is quite amusing (but boring) how your crowd of trolls has basically repelled everyone here on WUWT. Notice how it is basically you four or five, doing your shrill Real-Climate-type thing trying to shut everybody up. That is because people here know what real scientists actually sound like, arguing with reason and not claiming that THEIR scientists are the only real scientists.

        This hollering down everyone you disagree with – it’s not science. It’s shock radio.

        No one is here on this thread anymore, not because of you having convinced them of anything. The folks here at WattsUpWithThat have heard such shrillness before, and it’s boring. So they’ve left your group to feed off each other. You all haven’t won anything but the echo chamber of your own certainty.

    • Trent Telenko said @September 4, 2014 at 1:19 pm

      A large cluster of smaller bodies of the Tunguska and Chelyabinsk level could apply heat and blast waves over a huge continent sized area …

      Firstly, this is the “cometary impact theory of the origin of the [Carolina] bays”, dusted off and reapplied – to wit:

      The cometary impact theory of the origin of the bays was popular among earth scientists of the 1940s and 50s. … The conclusion was to reject the theory that the Carolina bays were created by impacts of asteroids or comets (Rajmon 2009).

      A new type of extraterrestrial impact hypothesis was proposed as the result of interest by both popular writers and professional geologists in the possibility of a terminal Pleistocene extraterrestrial impacts, including the Younger Dryas Impact hypothesis. It said that the Carolina Bays were created by a low density comet exploding above or impacting on the Laurentide ice sheet about 12,900 years ago.

      Supporters of the old Carolina Bays ‘soft shotgun blast’ hypothesis never abandoned the idea, although mainstream science discredited it decades ago. The parallels & connection with the new Younger Dryas impact suggestion have been plain since its inception, and can be found spelled out explicitly, as here.

      Secondly, although a continental-scale pattern of Tunguska-like airburst objects could deliver the necessary energy, properly-developing the mechanism by which the necessarily large original object is divided into sufficiently-small (but not-too-small) objects to be air-bursts, has the earmarks of a meaningful undertaking in itself.

      Third, comets are defined by their primarily icy (water) makeup, and as such would have a great deal less iridium etc (at best) than would a metallic-rich asteroid-type body … but which has greater strength and resistance to fragmentation, and far better penetration-characteristics.

      We do see ‘meteor-swarms’, which are sometimes very striking, but projecting these mostly sand & pebble ensembles up to a ‘fresh’ comet that has disintegrated in a particular manner … is a calculus that involves some large, unaccounted-for conditions & steps.

      • AGU monograph from 2012 makes mincemeat of this preposterous conjecture, and studies since then hammer even more nails into its coffin, some linked above:

        http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0CEwQFjAE&url=http%3A%2F%2Fwww.agu.org%2Fbooks%2Fgm%2Fv198%2F2012gm001209%2F2012gm001209.pdf&ei=YzsJVOK8AemejAKL2oCYDA&usg=AFQjCNERJCPDRNT01nhPsMC2B8Sf36JVQg&sig2=1C0UnZzPCzZjBliqWZrRSw&bvm=bv.74649129,d.cGE

        Arguments and Evidence Against a Younger Dryas Impact Event

        M. Boslough,1 K. Nicoll,2 V. Holliday,3 T. L. Daulton,4 D. Meltzer,5 N. Pinter,6 A. C. Scott,7 T. Surovell,8
        P. Claeys,9 J. Gill,10 F. Paquay,11 J. Marlon,10 P. Bartlein,12 C. Whitlock,13 D. Grayson,14 and A. J. T. Jull15

        We present arguments and evidence against the hypothesis that a large impact or airburst caused a significant abrupt climate change, extinction event, and termination of the Clovis culture at 12.9 ka. It should be noted that there is not one single Younger Dryas (YD) impact hypothesis but several that conflict with one another regarding many significant details. Fragmentation and explosion mechanisms proposed for some of the versions do not conserve energy or momentum, no physics-based model has been presented to support the various concepts, and existing physical models contradict them. In addition, the a priori odds of the impact of a >4 km comet in the prescribed configuration on the Laurentide Ice Sheet during the specified time period are infinitesimal, about one in 1015. There are three broad classes of counterarguments. First, evidence for an impact is lacking.
        No impact craters of the appropriate size and age are known, and no unambiguously shocked material or other features diagnostic of impact have been found in YD sediments. Second, the climatological, paleontological, and archeological events that the YD impact proponents are attempting to explain are not unique, are arguably misinterpreted by the proponents, have large chronological uncertainties, are not necessarily coupled, and do not require an impact. Third, we believe that proponents have misinterpreted some of the evidence used to argue for an impact, and several independent researchers have been unable to reproduce reported results. This is compounded by the observation of contamination in a purported YD sample with modern carbon…

        4. CONCLUSIONS

        An impact event as proposed by Firestone et al. [2007] is
        not consistent with conventional understanding of the physics
        of impacts and airbursts. We conclude that the YD
        impact hypothesis is not supportable, either physically or
        statistically. Much of the putative evidence for a YD impact
        is irreproducible. It is highly improbable that a significant
        impact event happened during YD, as conceived by Firestone
        et al. [2007]. Although the works published by the
        proponents of an impact event vary in description about the
        impactor, consideration of basic laws of physics indicate
        that such a fragmentation or high-altitude airburst event
        would not conserve momentum or energy, would lie outside
        any realistic range of probability, and therefore did not
        occur during the YD as described by Firestone et al.
        [2007]. This conclusion is supported by the present work,
        as well as a broad review of all the other lines of evidence
        critiqued by Pinter and Ishman [2008a, 2008b], Surovell et
        al. [2009], and Pinter et al. [2011a, 2011b].

      • It’s quite laughable that your group of trolls never onc mention the papers that refute these supposed “mincemeat” papers. I don’t even have to link to them, since all of them are mentioned at great length in the paper that is the subject of this post.

        Since you haven’t actually READ that paper, though, of course you wouldn’t know. You blow off the lab test – called empirical science – and pretend that any evidence that doesn’t agree with you doesn’t exist.

        Here at WUWT that is widely known as cherry-picking the evidence.

        Go read the paper. Then refute the refutations therein, if you can.

        I will NOT be holding my breath till you get back to us.

        This is a hypothesis with two VERY clearly defined groups arguing for and against it. The CON side has:

        M. Boslough, K. Nicoll, V. Holliday, T. L. Daulton, D. Meltzer, N. Pinter, A. C. Scott, T. Surovell,
        P. Claeys, J. Gill,10 . Paquay, J. Marlon, P. Bartlein, C. Whitlock, D. Grayson, and A. J. T. Jull, as listed above, plus Annelies van Hoevel.

        The list just from this one “Kennett” paper is:

        Charles R. Kinzie,, Shane S. Que Hee, Adrienne Stich, Kevin A. Tague, Chris Mercer, Joshua J. Razink, Douglas J. Kennett, Paul S. DeCarli (now deceased), Ted E. Bunch, James H. Wittke, Isabel Israde-Alcántara, James L. Bischoff, Albert C. Goodyear, Kenneth B. Tankersley, David R. Kimbel, Brendan J. Culleton, Jon M. Erlandson, Thomas W. Stafford, Johan B. Kloosterman, Andrew M. T. Moore, Richard B. Firestone, J. E. Aura Tortosa, J. F. Jordá Pardo, Allen West, James P. Kennett, and Wendy S. Wolbach.

        Notice that Richard Firestone isn’t even listed. Nor is R.

        I see a lot of new names in the latter list. It seems they are winning over new scientists. It’s not, of course, the numbers themselves. But it shows that despite the assertions by the Troll Group here, there ARE real scientists on the PRO side. It isn’t just some commenters here on WattsUpWithThat.

        The way these things are settled in science is by one group falsifying – proving false – the work of others. Not by insults and ad hominem attacks. Nor by asserting opinions. Opinions don’t count AT ALL as falsification. It takes empirical lab tests, experiments, and empirical field evidence to falsify.

        Anyone reading the actual paper will see the numerous failures the CON side has had in falsifying the impact evidence, laid out one after another after another.

        So far, not one of the claimed falsifications has held up to later scrutiny.

        THAT is the bottom line on the CON side – they still have no shells in their artillery. Every piece of evidence they have come up with has, ITSELF, failed.

        READ THE PAPER.

  83. sturgishopper could you list the cons and pros for the clathrate gun hypothesis to your way of thinking.

    I am not impressed by this theory in explaining climate change. It seems if anything to be the result of climate change not the cause.

    • Salvatore –

      While this paper shows evidence NOT supporting the clathrate gun hypothesis. the clathrate gun certainly should be part of what is considered as the cause of the onset of the Younger Dryas stadial.

      One paper does not a sufficient disproof make.

      I am highly in favor of the impact hypothesis, as I show above. But scientists should never settle on one hypothesis as mainstream (whatever it is) without considering ALL of the OTHER possible causes.

      Right now there are FOUR competing hypotheses for the extinction of the mammoths, and each school of thought is publishinig papers every month or three. They certainly cannot ALL be right, and most of the papers not only try to sell their favorite, but they typically try to shoot down one or more of the other three.

      I love the give and take. And I love reading them to see how others are shooting down the ones I don’t favor…LOL

      The impact hypothesis is the new kid on the block, so of course it is the target of much dispute.

      I find the clathrate phenomenon to be a terrifically fascinating subject.

      Thinking out loud, I would also think that in the case of an ocean impact clathrates would be more likely to erupt/be released, as a secondary phenomenon. One thing I have not heard much about is that since water is incompressible, it seems the shock of an ocean impact on the water should be considered as a destructive force, in and of itself, not just the tsunami. This is particularly odd, since in land impacts the shock is seen as such a major destructive force.

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