Kerr Watch

Elapsed time since Richard Kerr failed to inform his Science readers of the confirmation of nanodiamonds at the YDB: 6 years, 4 months, and 6 days

Breaking: New PNAS Study Claims Black Mat Blast Materials Common To Wetlands

I’ll soon have the actual paper, but below is Sid Perkin’s take at Science Magazine. The news article itself already reveals what appears to be a fundamental misunderstanding of the YDB team’s previous results. The YDB team does not claim the blast spherules are from space. They believe they are terrestrial. The Lake Cuitzeo paper restated this conclusion. (See graphic below). These authors appear to not understand this important aspect of the previous research.

Here is a snippet of write up below. This could well be Sid Perkins’ mistake (who I like), but it looks pretty suspiciously like the author does not know what the other side has been claiming:

…..he notes, the ratios of the concentrations of several rare-earth elements and other trace elements, including iridium, in the spherules embedded in the black mats match those found in Earth’s crust, not in extraterrestrial objects. Rather than coming from an extraterrestrial impact, the spherules were formed on Earth and then trapped in the ancient wetlands by natural processes, the team concludes. The dense spherules then sank to the base of the mat because they’re heavier than other windblown dust, sand, and silt. The chemical composition and location of the spherules, as well as their presence in black mats of many different ages, are more easily explained by natural processes than by extraterrestrial impacts, the team contends.

With the exception of one brief mention as a possibilty in 2007 paper I believe, the magnetic and silicate materials spherules have been ruled out as ET by the home team comet crowd. So then a major paper agrees — and it is news? People are misssing something here.

The YDB team thinks these things are from earth — somehow. This gets misreported, literally, ALL of the time. I have never seen it correctly reported, in fact.  It is too much fun to talk about rains of cosmic material, even if no one claims it. But other publishing researchers should not

As for their central hypothesis, it is intriguing and obviously of merit. Wetlands are indeed a store and sum of the temporal environment. What interests me is the kind of spherules found, and to what degree they were distinguished and characterized. From what Firestone says it looks like they used an optical microscope!?. But I am getting waaaay out ahead of myself…..stay tuned….

No Love for Comet Wipeout

by Sid Perkins on 23 April 2012, 3:05 PM

 

Did a comet wipe out woolly mammoths and an ancient Indian culture almost 13,000 years ago? Geologists have fiercely debated the topic since 2007. Now a new study says an extraterrestrial impact wasn’t to blame, though the scientists who originally proposed the impact idea still aren’t convinced.

Three unexplained phenomena happened on Earth around 12,900 years ago. An extended cold spell known as the Younger Dryas cooled the world for 1300 years. Large creatures such as mammoths, mastodons, and their predators went extinct. And the Clovis culture—a group defined by the distinctive stone and bone tools that they manufactured, and presumed by many archaeologists to be the first inhabitants of the New World—suddenly disappeared.

In 2007, a team of researchers tried to tie together these seemingly disparate events to a single cause: an extraterrestrial object, possibly a comet, exploded above eastern Canada, they speculated. Their claimed evidence, which has been much disputed since it was first reported, included several types of “impact markers” sometimes found after an extraterrestrial object strikes Earth. These purported markers include unusual grains of a titanium-rich form of the mineral magnetite; tiny magnetic spherules; and elevated levels of iridium, a relatively rare element that’s more common in extraterrestrial objects than in Earth’s crust. The researchers found all of these markers embedded within unusual layers of dark, organic-rich sediments that scientists often call “black mats.” These strata are the remains of ancient marshes and swamps, and at many sites across North America, especially in the American Southwest, black mats began accumulating at the beginning of the Younger Dryas, the researchers noted. Many paleontologists have noted that black mats are often a sort of dividing line between older sediments containing fossils of ice-age megafauna, and younger sediments that don’t. And many archaeologists have observed that black mats seem to mark the demise of the Clovis culture, because the distinctive spear points that they produced are common in sediments below the layers but nonexistent above.

According to the 2007 comet-strike hypothesis, large amounts of heat generated by the explosion of the comet shattered and melted much of the region’s ice sheet, suddenly flooding the North Atlantic with fresh water that interrupted ocean circulation, which in turn triggered an extended cold snap that wiped out the Clovis culture and polished off the last remaining ice age megafauna.

“It’s an appealing idea because it links all of these things together,” says Jeffrey Pigati, a geologist with the U.S. Geological Survey in Denver, who isn’t a proponent of the comet-strike idea. Unfortunately for that hypothesis, he and his colleagues report online today in the Proceedings of the National Academy of Sciencesnot all of the purported “impact markers” are produced solely by extraterrestrial objects striking Earth.

Pigati and his team studied black mats at 13 sites in the American Southwest and in the Atacama Desert of northern Chile—including some sites where the mats began accumulating 40,000 years ago. At 10 of the 13 sites, regardless of a site’s age or location, the researchers found all three of the “impact markers” described in the 2007 study, says Pigati. Although those presumed markers had also been found at a site in Belgium, he notes, they probably wouldn’t have dispersed to the South American sites he and his colleagues sampled in their new study, because effects of the purported impact likely would have been limited to the Northern Hemisphere.

Also, Pigati says, he and his team found supposed markers even at sites much older than 12,900 years—indicating that the purported impact couldn’t have been the source of those markers. Finally, he notes, the ratios of the concentrations of several rare-earth elements and other trace elements, including iridium, in the spherules embedded in the black mats match those found in Earth’s crust, not in extraterrestrial objects. Rather than coming from an extraterrestrial impact, the spherules were formed on Earth and then trapped in the ancient wetlands by natural processes, the team concludes. The dense spherules then sank to the base of the mat because they’re heavier than other windblown dust, sand, and silt. The chemical composition and location of the spherules, as well as their presence in black mats of many different ages, are more easily explained by natural processes than by extraterrestrial impacts, the team contends.

But the new study has several flaws, says Richard Firestone, an isotopic chemist at Lawrence Berkeley National Laboratory in Berkeley, California, and a member of the team that originally proposed the impact hypothesis in 2007. For one thing, he notes, Pigati and his colleagues didn’t use a scanning electron microscope to scrutinize the surface of the spherules—the only way to distinguish impact generated spherules, he says, that were melted at high temperatures and had a distinctive pattern inscribed on their surface as they splashed through the air, from the spherules commonly found in wetland sediments. Also, Firestone notes, Pigati’s team didn’t scrutinize all of the spherules, only the ones that were truly spherical—thus discarding many of the tiny markers that might have been generated by the impact, including teardrop-shaped blobs that cooled in midair as well as misshapen blobs that formed when one near-molten droplet bumped into another.

Pigati says he accepts Firestone’s criticisms but stands by his team’s findings and interpretations. “We admit in our paper that we can’t disprove the impact hypothesis,” he notes. “Our point is that some of the spherules and other markers [cited in the 2007 report] aren’t uniquely produced by impacts.”

  • E.P. Grondine

    First off, someone needs to tell Sid that its “Native American” not “Indian”, though it is likely that advanced Indian coastal civilizations were submerged by the end Ice Age melt waters.

    This kind of confusion really irritates people from India, who go to powwows seeking curry, only to find bufalo being eaten.

    It will be interesting to read this teams’ dates for their spherules. Given the pretty safe assumption that impacts occure far more frequently than previously hypothesized, they are likely to be evidence of other, different impact events than those of the HSIE.

    That proved true for the iron spherules from other dates. Any time you’re dealing with perfect spherules of homoegenous composition,
    it is possible that they represent plasma condensates of both the impactor and impacted surface, or for larger spherules, heated blast condensates. Particularly when they incorporate non local materials.

    I seem to recall Napier had a comparison with Murchison meteorite.

    As far as the global distribution of HSIE markers goes, as shown by the simultaneous multi-continental extinctions there was enough atmospheric dust loading to cause a nuclear winter. The impactites should be showing up in the southern hemisphere as well.

    Once again, in my opinion its going to take the location and documentation of one of the large HSIE astroblemes to close this discussion.

  • E.P. Grondine
  • Hermann Burchard

    Ed –

    It will be interesting to read this teams’ dates for their spherules. Given the pretty safe assumption that impacts occure far more frequently than previously hypothesized, they are likely to be evidence of other, different impact events than those of the HSIE.

    You are SPOT-ON, as usual. Haven’t read the Pigati et al paper yet but your interpretation was my initial reaction as well:

    THEY ARE LIKELY TO BE EVIDENCE OF OTHER, DIFFERENT IMPACT EVENTS

    These guys are likely doing a great job proving HIGH COMETARY IMPACT FREQUNECY. Here is the full reference for this early bird publication:

    http://www.pnas.org.argo.library.okstate.edu/content/early/recent

    Accumulation of impact markers in desert wetlands and implications for the Younger Dryas impact hypothesis, by Jeffrey S. Pigati, Claudio Latorre, Jason A. Rech, Julio L. Betancourt, Katherine E. Martínez, and James R. Budahn. PNAS 2012 ; published ahead of print April 23, 2012, pnas.1200296109

  • E.P. Grondine

    Hi Hermann –

    We’ll see. I think that Pierson will probably be analyzing their South American data in detail.

    You want to take on their North American data?

  • Hermann – “These guys are likely doing a great job proving HIGH COMETARY IMPACT FREQUNECY. [sic]”

    Just a nitpicky thing on my part…

    It bothers me when we or anyone talks about ‘proof’, especially early on in an ongoing area of research. Evidence is ‘supportive of’ or ‘suggestive of’ or ‘corroboration of’ a particular hypothesis.

    In the end, it is the overall body of evidence that persuades. Rarely does even that constitute proof. Usually it only makes up a paradigm – most of which eventually are superseded.

    In the absence of a meteor in the bottom of a crater, there is little in this field of study that could ever be considered persuasive. After all, meteors were found at the bottom of one or two Rio Cuarto craters, and the finders (the skeptics) actually claimed (if I recall) that they were from earlier impacts – in the same spot! So even a meteor in a crater can be read to mean something other than the obvious.

    What is proof to one person with a possible confirmation bias (us) can be read, then, as the exact opposite by the ‘other side’, which is smitten by their own confirmation bias in the other direction.

    ‘Proof’ is all in the interpretation.

  • Hermann –

    That link doesn’t work. It is some OK State restricted page.

  • Hermann Burchard

    Ed:
    Feverishly Working on Rough Draft for 3rd Maths Phil Paper. Must forgo any serious study of wetland dust capture claims.

    Q for George: Did YDIH papers by Feuerstein et al perform a mass spectrometer analysis of isotopic composition of Iridium? This would prove of disprove ET origin. The Pigati paper, which I looked at briefly, asks if black mat Iridium terrestrial. Isotope diagnostic decisive, ask Andrew Glikson, ANU geo-cosmo-chemist of renown.

    BTW, a few wetland black mats do NOT rival Hemisphere-wide YDr black mat. That’s like comparing my drive way with 5th Ave, NY.

  • Hermann Burchard

    Steve, George has promised to correct my comment.

    The correct link to list of contents of PNAS is:

    http://www.pnas.org/content/early/recent

  • George –

    You are describing a “Straw Man” argument.

    From our nemesis Wiki (LOL): “A straw man is a component of an argument and is an informal fallacy based on misrepresentation of an opponent’s position. To “attack a straw man” is to create the illusion of having refuted a proposition by replacing it with a superficially similar yet unequivalent proposition (the “straw man”), and refuting it, without ever having actually refuted the original position.”

    This is one of several forms of ‘logical fallacies’ used – usually when one knows one is losing the debate. Literally. Pointing out the straw man fallacy may, in fact, be a good way to belittle the opposition, accusing them of clutching after straws, since it shows they know they don’t have any real evidence against the YDIH. If they had real evidence, they would be arguing with THAT instead.

  • E.P. Grondine

    Steve –

    “In the absence of a meteor in the bottom of a crater, there is little in this field of study that could ever be considered persuasive.”

    Uhh, you don’t find meteors in the bottom of a large hypervelocity crater. You sometimes find meteorites from the shock lenses around the crater, but often the impactor is turned into bediasites and dust.

    What you do find around the crater is shocked quartz, shatter cones, ans other impacitites such as impact flour or impact quartz, foliated rocks, etc.

    From some smaller events, you find melt brecias or melts.

    These are not theoretical terms, they are descriptive.

    The current HSIE problem for Firstone et al. is sampling and identifying bediasites from 13,000 years ago.

    There are two other different approaches, one of which is to locate and sample the structure the Assiniboine remembered being formed.

    The other is to find the fire structures along the Cordillera.

  • Ed – “Uhh, you don’t find meteors in the bottom of a large hypervelocity crater.”

    I was slightly talking off the tup of my head, but had a few recollections of such finds. And that is not even to mention the fact that meteor craters are argued to not BE meteor craters unless a meteor is found in them. Are the scientists delusional, or am I mistaken in recalling all this?

    I am certain that Peter Schultz’s argument for Rio Cuarto being meteor craters was partly ‘refuted’ by Bland’s (?) finding of a meteor in the bottom of one of the craters which he had dated to long before the dates Schultz had found. While that argues something else as well, it – along with almost every establishment argument about possible ET craters – says that meteor hunters all look for meteors down inside craters. For example, no one yet has laughed at how silly the Tunguska search for a meteor must have been. It is always portrayed as the correct thing to do.

    So, all meteor craters do not have meteors?

    Almost nothing I’ve ever read says meteor craters do not have meteors. It may show the shallowness of my knowledge to admit all this, but when a lack of a meteor in the bottom of Rio Cuarto was originally argued as to why they were NOT impacts – and most other disputed impacts – how is one to understand the connection of meteors and meteoric craters?

    I also understand that Rio Cuarto was argued long and hard to not be meteors BECAUSE they had no meteors from the same time frame.

    I am not arguing against you, but asking for some elucidation. I may be an old dog, but I am capable of learning still. I am not asking about any of the other impact markers, only meteors.

  • George –

    I believe this is an ambiguous statement inn the write up:

    Rather than coming from an extraterrestrial impact, the spherules were formed on Earth and then trapped in the ancient wetlands by natural processes, the team concludes.

    “Rather than coming from an extraterrestrial impact” can mean either not from the BODY if the impactor OR that it did not come from the actions of an impactor. I wonder if he parsed that sentence’s meaning? What does “coming from an ET impact” mean? It can mean either.

    In the same vein, “Were formed on Earth,” can also mean either “by terrestrial mechanisms” OR would allow for forming ON Earth by an impact.

    I think this is a really imprecise and ambiguous sentence. And the reading of its meaning should not be left to the leanings of the reader. The author should make himself clear. Sorry if it’s a friend of yours, but perhaps an email asking for clarification would be in order.

    If I can read it both ways, it just isn’t well enough written. Yes, one way is a stretch – and maybe the full paper will clarify it, but IMHO it should have never been put out with this level of ambiguity. I have seen in global warming science where phrasings were discussed (in the Climategate emails) specifically to parse the meanings. They even did it with graphs, if you can imagine. I am not accusing anyone of being duplicitous, but meanings in research papers should be clear language.

  • The whole thing sounds like a cheap jab between two journals to me. Note that most of the YDB papers are in PNAS. Sid Perkins’s article is in Science Now which is a non refereed publication of AAAS.

    He makes a big deal of what the paper says about Firestone 2007, and completely ignores any more recent papers about the YDB. Apparently no one told him that arguing against the YDIH by tearing down Firestone 2007 became a moot point because the Lake Cuitzeo paper pretty much supersedes it as the flagship paper of the YDIH anyway.

    Bottom line, since they didn’t even use an SEM it’s really not a very important paper.

  • Dennis –

    All good points.

    And, yeah, the way Firestone did it has allowed a lot of sniping, because of all the misses in 2007. It was good in that it got the ball rolling, but hurried-up papers – all of them, it seems from then – are an invitation to get beat up on.

    Just an observation…

    Firestone works at Lawrence Berkeley NL and so does Rich Mueller who is the Nemesis hypothesizer and also who did a hurried-up mess of a nothing in global warming, taking NASA-GISS, NOAA and Climate Research Unit (England) data, running the math on it without vetting the data, and then releasing land-only and declaring that climate science was correct. He made a big to-do about it when they started and a big one when they finished their partial work – and then haven’t been heard from since. This after he’d gone on record – and on video – after Climategate I and declared that he wouldn’t trust their science as far as he could throw it.

    After those events, I am not so sure about either one of them. Mueller seems like a total flake, and the way Firestone handled the 2007 stuff, well, let’s just say he could have done everyone a favor by tightening up their work a bit.

    That is my take on it at the moment. Certainly everyone’s later papers invite much less criticism. But with the 2007 paper out there, the skeptics don’t have to even address those. They just have their field day on Firestone 2007 and laugh it up.

    Science Now is just a popularizer of science, so outside of giving the public the wrong impression, they don’t count. In the long term that article isn’t going to matter, but it probably sways a few minds. At the same time, it also keeps the issue in the public eye.

    What is it that is commonly said? All press is good press? Something like that?

  • You’re probably right Steve,

    That crappy article does keep attention on the issue. But in going after Firestone et al. they’re barking up the wrong tree.

    As it stands now, the paper to answer, or speak to for the science of the YDIH is no longer Firestone 2007, but the Lake Cuitzeo paper.

    Three years ago I started making the bold assertion that if you were interested in doing impact research in North America, and you weren’t looking in Mexico, you might as well be chasing butterflies in the playground and comparing notes. I took a lot of flaming and flack over that statement.

    A 10 cm thick impact layer in YD aged sediments in Lake Cuitzeo gives some weight to it though. But they’ve only begin to scratch the surface in Mexico.

    I also took a lot of flack when I said never mind looking for craters, but rather look for the signatures, whatever they may be, of very large cluster airburst events. I’ll stand by that one too. And since the YDB has written the idea of a cluster airburst event into refereed literature they’ve opened the door now to considering what something like that might do to the ground if not craters.

    But since the very idea of a cluster impact event, much less airbursts capable of planetary scarring are completely outside the uniformitarian paradigm you’ll find no joy or help from the geologists. Because finding and confirming a geologically recent airburst melt formation anywhere on Earth, especially if the blast-effected materials have been previously mis-defined as volcanogenic, will be the final blow for the old uniformitarian paradigm. And you might as well be asking the Pope to go along with evidence that there ain’t no such thing as Jesus.

    Time will tell. But the way I see it the significance of Lake Cuitzeo is that is about 100 miles outside the southern end of the Mexican impact zone. The cluster of fragments would’ve passed almost directly over that point coming in at a low angle from the southeast. And they would already have been well down into the atmosphere as they passed overhead.

  • E.P. Grondine

    Steve –

    Yes, you do not know the fundamentals of the field of impact studies.

    There are no meteorites at the bottom of a hypervelocity impact crater.

    Making the contrary assumption was the fate of Barringer and Kulik.

    When Moulton explained this to Barringer, who had already spent $600,000 trying to find the nickel steel, he died shortly thereafter.

    Shapley, later Velikovsky’s staunch critic, also pointed this out.

    Go back and re-read the papers on Rio Cuarto.

  • The Sierra bolide is starting to yield carbonaceous chondrite meteorite fragments. I just heard now that a NASA scientist found some pieces in a parking lot that had been run over by a car.

  • Dennis: “But in going after Firestone et al. they’re barking up the wrong tree.”

    I am agreeing with that.

  • Three years ago in letters to numerous scientists, including members of the YDB team, I was repeatedly told that a cluster airburst event would be “highly unlikely”. Also at that time I was asking why no one had looked for evidence in Mexico. And a comment that I repeated often in those conversations was that if you weren’t looking in Mexico for evidence of the YD event you might as well be chasing butterflies in the playground and comparing notes.

    Back then I wrote to Rick Firestone expressing confusion that Mark Boslough was coming out so forcefully against the YDIH because it seemed to me that the very same blast-effected materials that would prove the YD event would also prove Mark Boslough’s work on airburst phenomena in a big way. To my naïve way of thinking it seemed like they should be on the same side. […]?

    Dr. Firestone responded that he thought Boslough was being a bit disingenuous, because the estimate that it would take a 4 mile wide bolide exploding in the atmosphere to account for a continent wide debris layer was from the work of Toon et al. And that in 2007 they were well respected in the impact community and their work on impact scaling was considered the state of the science. Also at the time of that conversation, in a related conversation with Mark Boslough, he explained for me that he didn’t so much have a problem with the idea of a very large impact event as the trigger for the YD cooling, and the Mega faunal extinctions. But that his problem was specifically with the hypothesis “as written” because he could show that the physics just didn’t work.

    The trouble was that Dr. Boslough’s math was spot on, and he demonstrated almost conclusively that it is physically impossible for a 4 mile wide bolide to have enough time in the atmosphere to break up completely and scatter fragments, and debris over a continent wide area without making a good sized crater somewhere.

    But really, at the heart of the skepticism, and the fundamental flaw in Firestone 2007 was that at the time of its publication, they weren’t really working from a valid astronomical model. As a result they were all over the place in their speculations as to just exactly what had hit us. They could only offer speculation. And the only thing they were really certain of was that the event was different from anything that had been studied before.

    Clube & Napier had been talking about large clusters of smaller fragments since 1982 but in 2007 there wasn’t anything of their thinking in refereed literature yet. So the American school of thought and the British weren’t on the same page yet. But when you connect the dots, and you combine Clube & Napier’s large clusters of smaller fragments and Mark Boslough’s work on the physics of very large airbursts you come up with a scenario that can comfortably account for all of the evidence the YDB; multiple large cluster airburst events. Once you recognize that the thing was probably broken up into a cluster of smaller fragments before it even got close to the Earth Boslough’s very valid objections are handled.

    I was encouraged by the Lake Cuitzeo paper because in it, the YDB team had finally written the idea of cluster airbursts into the postulate. And supportive of my claim that Mexico was the place folks should be looking, they found a 10 cm thick impact layer.

    If you can describe a beast you can predict what its footprints should look like.

    In the search for relevant planetary scarring of the YD event it must first be recognized that since no uniformitarian geologist of the past could ever have imagined such a thing as a cluster airburst event, then he wouldn’t recognize the planetary scarring of one if he were standing in the middle of the impact zone.

    Think it through. The large airburst event that produced the Libyan Desert Glass was 29 Million years ago. The target surface was a desert full of clean silicate sand, so the resulting ablative melt is clear glass. The LDG event did not produce a crater, and was not big enough to produce a global impact layer. And yet after all that time there are still recognizable fragments of melt lying exposed on the surface.

    On the other hand, the YD event produced a global impact layer that gets dramatically thicker as you get into the southern end of North America; a fact which argues for a major impact zone in Mexico. And the Global distribution of the blast-effected materials argues for an event that was orders of magnitude bigger than whatever it was that hit the Sahara 29 million Years ago. So where’s all the melt?

    Since the target surface would’ve been ordinary alluvium, soils, and assorted volcanic materials, instead of sand the resulting ablative melt would not have taken the same form as the clean glass of the LDG.

    We are facing a major paradox in the Earth sciences.

    The simulations at Sandia Labs of the LDG event show the Airburst of a 120 meter wide fragment. In the resulting post impact vortex as the impact plume forms we see supersonic winds in direct contact with the surface at temperatures that greatly exceed the melting temperature of silicate rock for 15 to 20 seconds. This implies extremely efficient stripping, and ablation of the surface materials. A single fragment like that would’ve made a crypto-explosion structure 10 to 15 miles wide. And the Global distribution of the YDB implies a very large cluster of them.

    So what form do we expect the resulting melt to take? And how could the geologists have missed such a thing?

    The answer is that they didn’t miss it at all. They just misunderstood it.

    During an ablative event, and while all the particles and fragments of breccias, and melted debris are in motion they would’ve been suspended in a very high velocity cloud of super heated dust, breccias, and melt. In fluid mechanics such a cloud is called a density current or fluidized flow. In geology it’s called a pyroclastic flow. When a pyroclastic flow comes to rest, the resulting rock form is ‘ignimbrite’, a word which comes from the Latin for ‘Fire Cloud Rock”

    And that fact is at the heart of our paradox. Because the Earth sciences have always assumed without question that the only conceivable source of enough heat, and pressure to produce a pyroclastic flow is terrestrial volcanism. And they have always assumed that gravity pulling the cloud of breccias, and melt down slope away from a volcanic vent was the only conceivable motive force. They could never have imagined such heat, and violence coming down from above. Or that the hyper thermal supersonic winds of an airburst might be capable of providing the motive force for a pyroclastic flow that moved like the debris laden, storm driven, froth, and foam on a storm tossed beach.

    They didn’t miss the blast-effected materials in the impact zone of the YD event. They misunderstood their process of formation, and assumed without question they were volcanogenic.

    Of the tens of thousands of square miles of pristine ignimbrite sheets, breccias, and pyroclastic debris blanketing the Chihuahuan Desert as the undisturbed capstone of the terrains, less than 15% has ever been positively associated with a volcano. And the patterns of movement and flow that were frozen into them at the moment of their emplacement are perfectly legible. In other words, in high resolution satellite images one can track the movements of those orphan deposits like following spilled paint back to the can. There are no volcanic vents at the points of origin.

    So a question for the skeptics that’s every bit as valid as the question “where’s the crater?” is “Where’s the vents?”

    Since the Lake Cuitzeo paper confirmed my prediction three years ago that they’d find major evidence in Mexico, and since they have written the crazy idea of cluster airburst events into peer reviewed literature now. I’ll take it the next step, and go on record by saying that they have only just begun to scratch the surface of what’s to be found in Mexico.

  • Dennis –

    I read plenty of ‘valid’ in what you are saying.

    Comments on certain points (and pardon my ignorance on any or all points):

    “I was repeatedly told that a cluster airburst event would be ‘highly unlikely'” — This is nonsense on their parts,m whoever they are. 1994 SL/9 showed that multiples are still happening. Tunguska showed that airbursts of friable comet-density NEOs are still happening, on a geological time scale (as did this week’s Sutter’s Mill meteor). Thus any assertion of “highly unlikely” is ostrich-head-in-sand science. Such comments allow us to have very little confidence in those saying such nonsensical things. If one friable incoming NEO can airburst, what could possibly be their argument that multiples can’t?

    What specifically does Toon have to do with Boslaugh’s 4-km bolide?

    Even if the YDIH was not different from anything so far, after Tunguska and SL/9 scientists have to consider cometary impacts or air bursts. Those who only are looking at meteors are also ostrich-in-sand thinkers. Those other sorts of things DO happen, and if they do, anyone using meteor impacts as the sole model is the height of willfully ignorant. They should be brainstorming about the variations in impact/airburst markers that might be out there – and then actually looking for such evidence. Looking only for meteor signatures and no others is the height of “We know everything; there is nothing to see here – move along, people.”

    I just read today that the Saudi peninsula is a meteor hunters’ paradise right now. Australia has long been a meteor hunters’ paradise in its own right. Now the Sahara is being recognized as such, with the Libyan glass field finally being recongised as an airburst. 5-10 years ago everyone was walking around with their fingers up their rectums not having a clue about that. With so much of Mexico being desert there is no reason to think that Mexico – at the same latitude range as those others – should not also become a meteor hunters’ paradise.

    And speaking of that latitude range – more or less the tropics – I speculate that based on bell-curve statistical principles, simply looked at, the part of the Earth that aligns with the Ecliptic should be the most vulnerable to NEOs. And that latitude range is from the Tropic of Capricorn to the Tropic of Cancer, with less and less general likelihood as the distance from that area grows. No, that doesn’t mean I think every NEO is exactly on the Ecliptic; I know they are not. All NEOs have non-zero declinations. But on the average the bell curve should hold, over time (while probably being next to worthless over short spans of time, as in a coin coming up with six heads in a row, which happens). Also, I do know that Canada is a fertile field, too. MANY of those are so very ancient and a good deal I believe are from when Canada was not so far from the Equator. YES, Saginaw would be an outlier in such a cosmos.

    Lake Cuitzeo’s 10-cm black mat does imply closer proximity and that deserves to be considered. With more northerly black mats thinner, they appear to have been farther away.

    As to the Sandia air burst model, first it is a model and its correctness is dependent on the assumptions made. Take it from me, the global warming modelers have screwed the pooch on models, with their secret assumptions and secret formulas. Even if that model has all reasonably correct assumptions, it is in itself only one scenario. Low angle air burst are going to explode higher in the atmosphere because even though the air is less dense, the time within the atmosphere will be a larger factor than a straight-down impact. One needs to look at all entry angles. If they’ve done that, that is good.

    But I DO also suggest that if they haven’t done impacts/air bursts on/over ice sheets, that would be a next step. The entire equation changes a lot when rapidly expanding water>steam>plasma enters the equation. A considerable amount of expansion has to be added, not only impactites and impact breccia being thrown around. Pressures would grow, but by what percentage range I would have no idea – 5%? 15%? 30%?. I don’t know. But it is not the same thing. Peter Schultz’s hypervelocity data would be nice to see, to see what forces might be impacting the substrate.

    What I’ve seen of the Sutter’s mill bolide appears to show it as a high-density object that seemed to be probably not intersecting the ground – and even its high density didn’t protect it well enough. There is precious little imagery on that so far, so I could be completely wrong on this.

    Re Sandia’s 0.12km air burst simulation: SL/9’s 21 fragments ranged from 0.045km to 1.27km, averaging about 0.525km. With that big a variation, I would want Sandia to model that wide of a variation. There is nothing to suggest that SL/9 was atypical, and if we have real value for a planet inmpator, why would we not use them and see what kind of impact to expect on Earth? (It is possible such runs have been made and not been made public. The data would be useful, wouldn’t it?) With only two of SL/9’s fragments as small as the Sandia size, of what use is a 0.12km simulation? The third smallest was nearly twice as big as that simulation. I honestly do not see the use of that simulation, and I cannot imagine it was the only one run. After all, once the program is written it is only a matter of changing some input values to get more simulations.

    Re “cloud of breccia”, I think you may have misspoken: Volcanism’s main down-wind deposits seem to be ash pulverized down to 5mm to 0.4mm (and smaller) by explosively expanding magma gases and water into vapor/steam. And only the =0.5mm did not even make it to 100km away. The main deposited ash from 300km-700km was 0.4mm. Smaller ash was entrained in the air currents and went around the Earth. Breccias were not mentioned. A ‘cloud of breccias’ didn’t really happen there, I guess. I have only a small idea of how typical Mt St Helens was. Everything I can find about Pinatubo and breccias talk about laharic and pyroclastic flows.

    As to ‘high-resolution satellite images”, I’ve seen people bitten by such images in the past. Reading them can be a snake pit. I wouldn’t depend on them for anything more than preliminary assessment of ‘possible’ sites.

  • Steve asked:

    "What specifically does Toon have to do with Boslough’s 4-km bolide?"

    If you read Firestone et al you’ll see that the 4 mile wide bolide estimate wasn’t Mark’s. But rather, it was the specific point in firestone 2007 that Mark had a problem with. And where Toon et al comes into it all is when you read the references given in Firestone 2007.

    Toon et al’s work on impact scaling provided the basis for the 4 mile wide estimate in the first place. That’s why Dr. Firestone thought Mark to be a bit disingenuous. Since the 4 mile wide bolide thing was so wrong, then way didn’t he take it up with Toon et al too?

    There are more airburst sims being done. And more papers on the way. But SL-9 isn’t the only model we have of a comet breaking up. We also have very good images of the breakup of Linear, and SW-3. Both show a cluster of fragments rather than a longer string.

    The sims only provide clues to the nature of the truth we are looking for. They should never be confused with the truth itself. In fact, the truth we are looking for is written in stone somewhere. The true test of those sims will come when relevant planetary scarring is confirmed that is a match for them.

    And the only comparison ablative melt would have to volcanogenic ignimbrite is that the particles and fragments of melt, and debris would’ve been in a fluidized flow similar to a pyroclastic flow while in motion.

    But where a volcanogenic pyroclastic flow relies on a volcanic vent to provide the melted material, as well as the heat, and pressure to get the material into atmospheric suspension in a pyroclastic density current. And then gravity provides the motive force to move the pyroclastic materials downslope away from the vent, ablative melt may have similar appearance and properties when it comes to rest and cools to rest, but it formed by completely different phenomenology.

    In the case of ablative melt the source material becomes the melted, and ablated target surface itself. The heat and pressure to get the materials into a pyroclastic density current is the hyper thermal, supersonic winds at ground level of the ablative airburst. Those same winds provide the motive force for the resulting pyroclastic flows of ablated materials. And the flows come to rest outside the blast zone as soon as the wind pressure is no longer strong enough to provide that motive force to keep it moving.

    For the purpose of identifying candidate locations for field work the key is in recognizing that the differences in motive force should be expected to result in completely different patterns of movement and flow during emplacement; one wind-driven, the other gravity attracted.

    A volcanogenic pyroclastic flow was pulled downslope away from a volcanic vent. Gravity pulling it from the front provides the motive force.

    The blast-effected materials of an ablative event relied on wind pressure pushing from behind for the motive force. So first of all when you look behind the flow you won’t find a vent.

    There are numerous pristine crypto explosion structures in the Chihuahuan desert which display a radial curtain of pyroclastic materials, and breccias. There can be no question that the point of origin for the radial pyroclastic curtain is the center. But at the center of one of those radial outwards flowing pyroclastic flows, instead of a volcanic vent, you’ll find a central uplift consisting of shocked materials like shatter cones.

    So just in one of those crypto explosion structures we see a perfect match for the patterns of ablative wind flow seen at the surface in one in one of the Sandia simulations.

  • Dennis –

    Thanks for the Toon info. It’s been a LONG time since I read Firestone 2007. Maybe time to bone up – but with all its flaws, yaddah yaddah yaddah…

    SL/9 vs Linear and SW-3 – do they have any idea of the fragment sizes? It would be nice. I suspect not. They had to calculate and model to get the sizes of SL/9 AFTER the impacts. I see we are much on the same side on the models. I figure the models are possibly off by 20-30%, too, but close enough. Good. But SL/9 stands as the only reasonably solid info, IMHO.

    The clusters – does that mean the breakup is still recent? Or does it mean a smaller body broke them up? It is a scary shot-gun scenario that comes to my mind. If their break-up vectors were OUTWARD rather than along the orbital path, our impact chances go up. And our multiple impact chances go up, too.

    BTW, one of the things multiples do is they confound the ‘expected’ impact frequency of impacts (which is at best semi-crap because the assumptions are only assumptions). But turning one 1.8km object (as in SL/9) into 20 objects up to 1.3km, that cuts 100,000 years down to 5,000. And if they are already NEOs… The three 1.0km to 1.3km fragments, based on what was seen in 1994, would have mushroom clouds far bigger than the planet Earth (in our gravity vs Jupiter’s), and anyone not jumping on that like a fly on feces has his career as a higher priority than the survival of his species.

    Then roll in Encke’s 3.3 year orbit as the same for the other Taurids, and the higher density part of the stream we get to wave to just as often, so any responsible investigators would be on these in a flash. It boggles my mind why 18 years later so little has been done. And the responsibility comes down first on those with the big toys to play with like Schultz and Boslough, and if one of those is saying, “I am gonna quibble with the numbers, and it is no big deal” even with Tunguska only 104 years ago (which is like yesterday), oy vey.

    Ablative melt flow vs volcanogenic – Your take on that is probably more or less correct, because it doesn’t matter HOW the rock got up to temp, once up to a particular temp they would give up their heat at the same rate. Cooling has nothing to do with the method of the prior heating.

    Following your thinking on the pyroclastic flows, from both Boslough’s and Schultz’s results, I would say the atmospheric wind pressures are as nothing compared to the forces of impact>ejection. Both their work seems to show impact material to go essentially straight up (out of the troposphere and on large objects likely out of the stratosphere). Once at elevation, I would see the lateral movement to be relatively small. With maybe 90-99% of the lateral forces coming from the impact itself, unless it hit on an ice sheet, I can’t see much outward vectoring. Also, pyroclastic flows are very much dominated by gravity, so what goes essentially straight up will come down essentially straight down – not exactly, but I would see atmospheric winds as being very secondary or less. The outward vectors, including winds, would not carry materials very far, IMHO. I can’t see external winds – even those supersonic ones entrained in the updraft – as having any capacity to more than nudge the debris column inward a little; I can’t see it pushing the entire column at all. Its entrainment upward would begin before it even got to the real mass of rising materials, and any sideways vectors would be lost pretty shortly, once it is entrained upward. Not picking a fight, just seeing it a bit differently. That is only my best internal processing of it as I see the accumulated bits. It is good we have varying takes on it. That gives us collectively a more open approach.

    BTW, I DO agree that the larger ejecta coming to rest outside the blast zone – but I can’t see that normally being very far, based on the USGS St Helens numbers. I TRIED like the dickens to find other ash dispersal data, but so far no success. So, for now, that is all I have to work with. And it says heavy acorns fall close to the oak tree.

    With an ice sheet impact or air burst, I see an entirely different scenario. I see the explosively expanding water vapor adding an enormous outward vector. How much is ‘enormous’ though, when compared to the forces of an impact? Maybe not a whole lot. But maybe enough to double or quintuple the dispersion and maybe enough to vault even larger masses upward (the water vapor expansion is not only outward) and much more outward. And as I’ve said before, the expansion is not on a continuous train of material exiting a volcano’s main vent, but it is all at once, in a period of seconds, not hours or weeks. The expansion forces from water turning to vapor would be quite large. Solid materials in close proximity would not just have expansion, but an tremendous impact, pulverizing them and driving them outward. Once turned to vapor, more heating would happen, but would not have the expansive force anymore. So all the ‘boost’ from water vapor would be in the first seconds and however fast that extra pressure bubble can expand.

    As to your Chihuahuan desert features, I agree with most of what you day, but I don’t see wind being more than a tiny factor. The expansion from the air burst would be several magnitudes more of a factor than wind. IF by wind you do mean the air burst expansion, I would agree with you. But I wouldn’t call it wind. It seems the first to arrive would be the radiant heat, which would melt and soften the existing cerro surface. Then after the melting/softening the expansion blast force would arrive and push the materials downslope and with some horizontal force vector from the incoming velocity vector. I can’t see the atmospheric wind being any factor, but the carried-in velocity vector cannot just disappear, and it would be unbalanced a (relatively) small amount in the path direction.

    In Schultz’s hypervelocity experiments, the upward forces come from the downward forces reflected off the substrate, almost doubling the upward force. In physics an unbalanced force MUST create motion. For any unbalanced force to be stopped from creating motion, the force has to have a counter force – a reaction force – equal to its own force. In buildings, the downward force is countered by the ground delivering a reaction force upward. If the ground is too weak (soggy, swampy, etc.) then the reaction force can be too weak, and the building will ‘settle’ or sink. But sooner or later the gravity force is counterbalanced and the settling stops (usually). When slightly too weak soil is dealt with, then spread-out ‘footings’ are designed in, to allow the downward forces to be spread out over a larger area. This lowers the p.s.i. of the downward gravity force while still dealing with the same total force.

    You probably know all this, but… In an impact, the point force is enormous and the ground surface cannot ‘react’ enough, so it gets pushed down and down and down – but also outward, because of both its internal pressure being built up and because the impact force vectors are not only straight down but are 360°-360°. The ground is pushing back all the time, just not enough, so the crater keeps getting deeper and wider. Wider here is an important element, because if the crater stayed the same diameter, the crater would end up a LOT deeper. (All of this depends on the internal yield strength of the ground material, as it is internally sheared crystal from crystal or molecule from molecule). When the outward push AREA multiplied by its ability to push back (reaction p.s.i.) equals and then exceeds the downward force, the crater will not really get any deeper. After this point the downward force gets reflected back on itself and is then added to the upward force. (Outward forces continue, diminishing by a factor of 1/r^2, but also diminished by the ground’s resistance in that direction, too.) So the greatest vector in an impact is upward, as reflected (no pun intended) in Schultz’s and Boslough’s experiments and models – and it all comes, not from the impactor itself, but from the ground’s ability to resist the downward forces. (In fact, I am virtually certain, from my basic understanding of materials, that the glassification and nano-diamonds come not from the impact, but from the particular material’s ability to resist the impact force and not get blown to smithereens (a very scientific term there).

    So, the Chihuahuan desert effects you are pointing at are FROM the impactor, but their particular features come from the ground’s particular abilities to resist the impact forces. Had they not been subject to the radiant burst first, they would look considerably different. They most likely would be shattered. That there are breccias has to be because some of both was going on. Yes? I see impact breccias coming from molten closer-in materials being driven into and shattering more outlying materials, then filling the new cracks and later hardening like bricks and mortar. I can imagine how fast that melt flow happened, and a lot of it was more like impact than push.

  • The biggest difference I see between SL-9 and Comets like Linear, or SW-3 is the apparent mechanism of their breakups. Most of the data on SL-9 implies that it was stretched out into a long string of fragments by tidal forces in a close pass of Jupiter before it returned to finally impact. Whereas Linear, and SW-3 appear to have broken up in the inner solar system because the ices holding them together simply sublimated away until they just came ‘unglued’ in the warmth of the sun like the wings of Icarus.

    In your description of the well known kinetic impact cratering process it’s clear you’re not thinking “cluster airburst” yet. In doing so you are assuming that you can use something that’s been well studied to understand, and describe something that from the very beginning was recognized by Firestone et al as being something very different from anything anyone has ever studied before. That simple observation by them may go down as the understatement of the century. On that point they were absolutely correct. And I’m afraid there is nothing in the standard knowledge toolbox for this one. The only solutions for the YD event are outside the box.

    One thing to get away from is the use of the word “impactor” as in thinking singular. Also, the use of the word ‘impactor’ implies the ground had to resist the downward force of a direct kinetic transfer of energy from a solid hypervelocity object. It didn’t.

    That’s not the case in an ablative airburst event. Since almost 100% of the kinetic energy is translated to heat in the atmosphere, then the thing the ground has to resist is the efficient stripping, and ablation of the surface by the hyperthermal, supersonic winds of the airburst vortex, and not the shock of a kinetic impact.

    The thing about the Chihuahuan desert is that once you identify one crypto explosion structure, and you learn to recognize what the footprint of a single large ablative airburst vortex looks like, the next step is to follow the trail of violence to try to get a handle on the full extent of the impact zone. I’ve been studying it for three years now. And I can tell you it’s much bigger than anyone thought.

    When you do battle damage assessment from aerial photographs there’s a basic forensic principle you use that applies here as well. And that’s that if you want to get a handle on an explosive event after the fact, you begin by studying the visible patterns of movement in the blast-effected materials. If you want to get a handle on just exactly what exploded, you collect samples from the ground in the blast zone, and you do detailed chemical analysis of those materials. But if you really want to understand how the explosive event unfolded and progressed you study the patterns of motion that left their signature in those materials during their emplacement.

    I’ve gone into it in detail on my blog, and lot more detail in a book I’m writing. But for now suffice to say that from a forensic blast analysis perspective; the full extent of the violence the visible blast-effected materials in Mexico describe is at least an order of magnitude worse than anything anyone has ever imagined or described.

    Think ‘cluster airburst event’ as the Lake Cuitzeo paper proposes. Then take that scenario to its worst case extreme. Once you’ve done that realize that your imaginary ‘worst case scenario’ is probably way too naïve and conservative.

    The event that hit Mexico wasn’t just a meteor ‘shower’ of individual fragments. It was a full blown, once in many millions of years, mass extinction level, super cluster airburst storm. The scale and number of overlapping crypto explosion structures in the impact zone describe a dense cluster 200 to 300 miles wide that came in at a low angle of about 30 degrees from the southeast. And as I’ve said before, Lake Cuitzeo is about 100 miles outside the southern end of the impact zone. So the cluster would’ve passed directly overhead of that location. And the fragments were already well down into the atmosphere at that point. The cluster appears to have had the kind of fragment size, and distribution you see in the images of Linear. And my guess is that the average fragment size was at least 100 meters. Although there are a couple of locations that imply fragments as big as a kilometer. It was the kind of thing you would only expect to see if a large comet hit very soon after its complete breakup, and before the fragments had time to disperse much.

    “Shotgun blast” was a good comparison, but still a bit wimpy. Imagine a cluster of large fragments so close together that only those on the leading edge fall into cold atmosphere, the rest fall into the already superheated impact plumes of the ones that led the way, and just crank up the heat.

    You’re right about ‘multiples’ confounding things. Planetary scientists have always assumed a constant flux of single bolide impacts. So they use their unproven assumptions of impact frequency to estimate the age of a planetary surface by counting the number of craters in any given surface. But it’s getting pretty hard to ignore evidence that Clube & Napier were correct that the breakup of comets is a common path to their destruction. We’ve got Linear, and SW-3 to name just two. They can’t escape the fact that since those common multiple fragment objects are in short period orbits that cross those of all the planets of the inner solar system, it’s only a matter of time before a planetary surface gets hit by one. And all it would take is one multiple fragment event to throw their age estimates off by billions of years.

  • E.P. Grondine

    Steve –

    The Mexican Desert has been hunted for years by Mexico Doug (who graciously helped me get around the Tucson show and arranged for me to get some nice Allende samples for educational purposes).

    If there are any impact melts in that area, Doug has never noticed them or found them.

    Saudi Arabia and Australia both have fairly strict meteorite hunting laws.

    The Sahara (North West Africa) has been hunted for a little over a decade, and while there is likely to be more meteorites found there, IMO it is a good time to buy Lunar and Martian meteorites. (This is simply my guess, and should not be considered as investment advice.)

  • E.P. Grondine

    Mr. Cox –

    Finally at last a semi-coherent statement from you.

    Point by point, indeed American and British impact science differs. The specific reason for that difference is Dr. Morrison’s mistakes on injection mechanisms and the frequency of cometary impact, and his insistence that both his comet impact estimates and injection mechanisms were correct.

    You knew what scaling laws are, and you knew a couple of the people who work on them at the time you launched your first barrage of invective at me. You can also find a scaling law cited in my book. Generally, those who work with scaling laws do not discuss them much with people outside of their community. Based on your behavior here at the Tusk, I myself would never introduce you to even the most public of them. Period. No matter how many times you call me a “liar” or call my
    work “bullshit”.

    My objection to your hypothesis is and has been with your application of Boslough’s scaling laws, and your wildly incorrect estimates of the kill radii of your multiple Mexican airburst scenario.

    Do the math. Assume all your features are impact features. The kill radii from Boslough’s scaling law still do not extend to eastern North America, not even to the Mississippi River. Neither the IR nor blast over-pressures.

    Animals and people died of starvation and cold during a “nuclear winter”, not from direct blast effects, as you maintain.

    As far as the pyroclastic structures in Mexico go, as you know they are generally thought to be exposed features from far earlier volcanic eruptions. Shatter cones are shatter cones, and erosionally exposed volcanic cores are erosionally exposed volcanic cores.

    As you point out, the contents of volcanic pyroclastic flows and surface melts do differ.

    Not all geologists are uniformitarian.

    Given the vast area you are looking at, even if you can find one geobleme, you will still have the problem of showing that it dates to the HSIE.

    There are other possible sources for the strata seen in Mexican lake than your hypothetical “features”.

    In the meantime, the debris chain of SE3 (73P) is not exactly a “theoretical” hazard, as by last calculations it is due in our vicinity in 2022.

  • Ed said:

    “Finally at last a semi-coherent statement from you.

    Point by point, indeed American and British impact science differs. The specific reason for that difference is Dr. Morrison’s mistakes on injection mechanisms and the frequency of cometary impact, and his insistence that both his comet impact estimates and injection mechanisms were correct.”

    I’ve heard enough of your immaterial and off topic ad hominem crap about David Morrison to make me puke for a lifetime. Beyond that, I see no reason to dignify this latest impertinent off topic tripe with a response.

    “You knew what scaling laws are, and you knew a couple of the people who work on them at the time you launched your first barrage of invective at me.”

    You demanded that I talk about scaling laws of airbursts. I said that no such work had ever been done yet. You asserted that it had. You said that I should know about scaling laws of airbursts, and you came back at me like I must be some kind of idiot for not knowing about the amazing non existent science you just pulled out of your butt . I called you a liar on that one. And even when challenged to produce a paper on the scaling of airburst phenomena you never did. That challenge still stands.

    That "First barrage of invective" was a response to someone who has no academic credentials whatsoever, yet demanded that I should conduct my own work by his rules as if his was the only and final word on the subject. And when I didn’t, that person demonstrated the reading comprehension skills of a ten year old, as well as the logic and debate skills of a five year old with a constant barrage of empty and meaningless straw man arguments, personal ad hominem insults, humiliation and invalidation. And never at anytime when challenged to provide a valid peer reviewed reference to support his own claims of vast knowledge has that person ever cited a single peer reviewed paper.

    “You can also find a scaling law cited in my book.”

    I never place assign relevance, or importance to anyone’s self reference. Unless that reference is something the individual has published in refereed literature. If I don’t believe what you say, the fact that you wrote it down somewhere doesn’t change my mind. Anyone can say anything in a self published book.

    “Generally, those who work with scaling laws do not discuss them much with people outside of their community.”

    I don’t know, I haven’t had a problem connecting with world class physicists. As a matter of fact I’ve found that some of them make great friends, and mentors.

    “Based on your behavior here at the Tusk, I myself would never introduce you to even the most public of them. Period. No matter how many times you call me a “liar” or call my work “bullshit”.

    Since I really don’t want anything to do with you, and since I have a very low opinion of your own behavior and academic integrity, I’m pretty much Ok with that.

    “My objection to your hypothesis is and has been with your application of Boslough’s scaling laws, and your wildly incorrect estimates of the kill radii of your multiple Mexican airburst scenario.”

    That’s an amusing and ineffective straw man argument. Since Mark has never published any “Boslough’s scaling laws” And I’ve never made any estimates or written anything about “kill radii. But in case you hadn’t noticed, I’m not terribly concerned about your objections to my hypothesis anyway.

    “Do the math. Assume all your features are impact features. The kill radii from Boslough’s scaling law still do not extend to eastern North America, not even to the Mississippi River. Neither the IR nor blast over-pressures.”

    Since you are citing non existent work again, there’s no math to do. And that’s a straw man argument inside a straw man argument anyway. It’d help if your reading comprehension skills weren’t those of a ten year old, and you had as good a grasp on the science my work is based on as you like to pretend you do.

    “Animals and people died of starvation and cold during a “nuclear winter”, not from direct blast effects, as you maintain.”

    Since there is nothing in my work that says how I think the animals and people died, that’s either another straw man argument, or more evidence of your poor reading comprehension skills, or both.

    “As far as the pyroclastic structures in Mexico go, as you know they are generally thought to be exposed features from far earlier volcanic eruptions. Shatter cones are shatter cones, and erosionally exposed volcanic cores are erosionally exposed volcanic cores.”

    I’m well aware that I am in almost complete disagreement with what is “generally thought” about the Geomorphology of the region I’m studying

    “As you point out, the contents of volcanic pyroclastic flows and surface melts do differ.

    Not all geologists are uniformitarian.

    Given the vast area you are looking at, even if you can find one geobleme, you will still have the problem of showing that it dates to the HSIE.

    There are other possible sources for the strata seen in Mexican lake than your hypothetical “features”.

    Three years ago I began writing about what I perceived to be the impact zone of a vast cluster airburst event. Without reading a word of that hypothesis until last month, you dismissed it as the mutterings of a lunatic.

    And then Isabel Israde-Alcántara et al. (The YDB team) went to a lake about a hundred miles outside the southern end of the “imaginary” impact zone I had described in my “lunatic mutterings”; and a location where the fragments of the super cluster I proposed would have been well down into the atmosphere as they passed over head towards the impact zone I had already described. And darned if they didn’t find a ten cm thick impact layer that they said was consistent with something very large screaming though the atmosphere directly overhead. They even wrote the crazy idea of a cluster airburst event into the postulate this time. I might be a lunatic. But I’m not alone anymore. I’ll stick to my guns.

    If you have a better idea for a source for the blast-effected materials in the impact layer the YDB team found in Lake Cuitzeo then what they propose in the new paper you should share it with us.

    In the meantime, the debris chain of SE3 (73P) is not exactly a “theoretical” hazard, as by last calculations it is due in our vicinity in 2022.

    I’ve never said Scwassmann-Wachmann3 isn’t a threat.

  • E.P. Grondine

    Mr. Cox-

    Point by point.

    There is nothing ad hominem in my comments on Morrison’s mistakes. He was a pioneer in the field, and thus he made some. We all do.

    The problem laid in what he did later on.

    The scaling law I used is CITED is in my book. I used it after consulting others. It covers air bursts as well, but as point explosions. Boslough’s contribution was the partial preservation of momentum in hypervelocity airbursts.

    In as much as you’ve repeatedly mentioned Boslough’s model, it clearly exists, and it covers airbursts. You’ve also made claims as to “features”.

    So, do the math, and calculate the kill zone for each of your features, and then sum to get a total kill zone.

    If your formation hypothesis is correct then similar strata should show up in the southwest of the US as well as from areas in Mexico surrounding them.

    Please remember that one impact, or even cluster airburst, does not exclude other simultaneous impacts.

    There are other impact strata from elsewhere which have not been published yet that are thicker than that from the Mexican lake.

  • E.P. Grondine

    In the meantime, NASA once again claims that comets do not hit. Period. Straight from NASA Ames:

    http://www.nasa.gov/home/hqnews/2012/apr/HQ12-135_Asteroid_Imapcts_Earth_Rocks.html

    The start of Firestone et al’s problem was that they did not claim that a carbonaceous asteroid hit instead of a comet.

    It will be interesting to read about the composition/formation times of the spherules.

  • I wonder if somewhen plasma physics will help to clarify some of the questions which continue to make impact so difficult to prove? I also remember that Clube and Napier hypothesized an enormous body entering into the inner solar system 30-50k years bp and the resulting slow breakup resulted in a continuous bombardment of the earth in the intervening millennia till at present all that is left are the particles which compose the zodiacal light, and Encke. Though it is possible my readings included others hypotheses concerning the Clube/Napier theory.

  • E.P. Grondine

    Perhaps a better way of putting it is that hypervelocity impacts will clear up plasma physics:

    http://www.nasa.gov/home/hqnews/2012/apr/HQ12-135_Asteroid_Imapcts_Earth_Rocks.txt

    Once again, according to NASA, comets do not hit.

    Clearly, Firestone et al.’s key mistake was insisting that a comet hit, instead of a carbonaceous asteroid.

    Its going to be very interesting to compare spherule compositions with their formation dates.

  • Popeyesmotto said:

    “I also remember that Clube and Napier hypothesized an enormous body entering into the inner solar system 30-50k years bp and the resulting slow breakup resulted in a continuous bombardment of the earth in the intervening millennia till at present all that is left are the particles which compose the zodiacal light, and Encke. Though it is possible my readings included others hypotheses concerning the Clube/Napier theory.”

    Your’re close, But in fact they proposed that the Taurid progenitor object entered the inner solar system between 20,000, and 30,000 YA, And that its progressive breakup over ensuing millennia comfortably straddles the Pleistocene/Holocene transition.

    If you’d like to read it again, your reference, and the astronomical model now cited and used by the YDB team in the Lake Cuitzeo paper is Palaeolithic extinctions and the Taurid Complex, by W. M. Napier.