Exploring abrupt climate change induced by comets and asteroids during human history

Skeptic Speaks: A Personal Essay from Vance Holliday on the Clovis Comet

Vance Holliday

Vance Holliday was thoughtful to give the Tusk a heads up on his essay first published here at the Argonaut.  I have not read it throughly enough to respond myself right now, but I am certain of this: One or more of the dozen key researchers from the other side of the debate should write something similar.  His tender tale of woe and misunderstanding is exceeded only by their own.

Take it away, Dr. H:


A personal perspective on an Outrageous Hypothesis

I first became aware of the idea of some sort of late Pleistocene “cosmic event” in the late Spring of 2007 when, like may other scientists, I heard about a symposium on the topic at the American Geophysical Union meetings in Acapulco where the hypothesis was essentially unveiled to the scientific community. I heard that this “event” was responsible for late Pleistocene extinctions, the demise of the Clovis “culture” and dramatic climate change in the final millennia of the Pleistocene. I was interested in the hypothesis because I’ve spent many years investigating topics that the hypothesis addressed, including Paleoindian archaeology, and late Pleistocene paleoenvironments and paleogeography. I was skeptical because, well, we are supposed to be skeptical of new hypotheses in science. More specifically, however, several things bothered me:

In no particular order…

1) The cause of the late Pleistocene extinctions has been debated for decades. Significant points that often gets lost in the debate are that: i) it is not clear that all or even most of the mammals facing doom in North America survived until the “event” at 12.9k and ii) the extinctions were global and the timing and composition of extincted fauna varied from continent to continent. Invoking a comet to do the deed simply makes no sense.

2) I was pretty familiar with stratigraphic records on the Great Plains and in the Southwest, and very few provided any indication of any particular “event” at 12.9k.

3) I was very familiar with Paleoindian archaeology and geology, especially on the Great Plains, which has the highest concentration of in situ and dated Paleoindian sites on the continent. I knew of no archaeological or stratigraphic “discontinuities” at 12.9k.

4) There was no consideration of the depositional environments that yielded the impact indicators.

5) I was struck by the absence of data or even opinion that cast doubt on the hypothesis. I felt like I was being “stampeded” by the proponents of this hypothesis, and that always raises questions in my mind.

Then, more or less by coincidence, I was going to be in Lubbock, Texas, in the summer of 2007 about the same time as Jim and Doug Kennett, who are part of the Clovis Impact team. We arranged to meet at the Lubbock Lake site, where I’ve worked on both the archaeology and the geology since the 1970s. The Paleoindian stratigraphy at Lubbock Lake is very similar to that at the Clovis site in New Mexico (aka Blackwater Draw site), about 120 km to the northwest. They had some data from Clovis that supported the impact hypothesis. Alan West, another member of the Impact Team, had been to Lubbock Lake earlier and found a lot of magnetic material in the Paleoindian deposits and declared that it, too, had a record of magnetic particles (considered key impact indicators by the Impact Team at the time) that supported their hypothesis. I was skeptical of that claim, too, because magnetic particles are common in all sorts of sediments, including those in and around the Lubbock area. Nevertheless, we agreed that the Lubbock Lake stratigraphy was worth further investigation.


In the Fall of 2007, I proposed collecting samples across the “Impact Zone” at 12,900 years BP at Lubbock Lake and also at the San Jon site. San Jon is a Paleoindian site in one of the thousands of small playa basins that dot the High Plains surface. Based on a lot of field work I conducted during the 1980s and 1990s, I knew that the sediments that fill the playa basins are a homogeneous mud that began accumulating before the time of the purported impact. And most everything that was deposited in the playa basins stayed there. Further, San Jon is only 80 km north of Clovis. If an airfall record of an impact was to be preserved anywhere, it should be in the playa basins.

I also proposed collecting samples from both Lubbock Lake and San Jon, because I had worked out most of the stratigraphy and geochronology at both sites, and would submit them blind to the Impact Team (i.e., they would not know the stratigraphic sequence or radiocarbon age of any of the samples). The idea was 1) to see if we could produce the same results at those sites as they claimed to have from other similar sites, and 2) to see what sort of results the Impact Team would get from these samples. Would they support the Impact Hypothesis? and would their results be the same as ours? Reproducibility of results is a fundamental aspect of hypothesis testing. I also got in touch with Todd Surovell at the University of Wyoming. I knew he had an interest in this hypothesis, and he said he would process samples to look for the magnetic grains and magnetic microspherules using the procedures supplied by the Impact Team. Having two independent teams, one not in any way affiliated with the Impact Hypothesis, working on splits of the same samples was also another important way of assessing reproducibility. Alan West confirmed Todd’s identifications of magnetic microspherules from Lubbock Lake.

During 2008, Todd Surovell began contacting other investigators and obtained samples from other localities; some investigated by The Impact Team, others not previously studied. In the Fall of 2008, I also collected a section at the Clovis site (Blackwater Draw Locality #1) that was previously collected by the Impact Team.

In the meantime, I came across a book by Firestone, West and Warwick-Smith: The Cycle of Cosmic Catastrophes: Flood, Fire, and Famine in the History of Civilization (2006). It was the first publication to present the Clovis Impact hypothesis but had gained little attention until after the AGU conference. When I first picked it up, I casually flipped through it and kept coming across comments that I knew to be misstatements if not grossly in error. For example, my own research on playas was completely misstated, and what were purported to be my conclusions were essentially the opposite of what I said! They state (p. 216) that because I had a suite of radiocarbon dates from “the underlying formation” (i.e., from below the fill in the playa basins, which they mistakenly refer to as “salty salinas”), then these depressions must have formed at about the same time as the Carolina Bays (according to their discussion elsewhere, at about 12.9ka), and they must have been formed by the Impact Event. The problem with this interpretation (as well as interpretations of the Bays – see below) is that my dates were from the playa fills, which is very clear throughout the paper, andtherefore the depressions must be older than 12.9k. How could something so clear and straightforward be so stunningly misinterpreted and misrepresented?

See Holliday, V.T., et , 1996. Stratigraphy and Geochronology of Playa Fills on the Southern High Plains.Geological Society of America Bulletin, 108: 953-965.

The dating of the Carolina Bays (thousands of elliptical depressions scattered along the Atlantic Coastal Plain) was also largely ignored or misstated (p. 127). One minute spent searching the internet turned up three GSA abstracts with OSL dates clearly showing that the sand rims around some Bays date to between 15,000 and 40,000 years BP and between 70,000 and 80,000 years BP. Some rims were active “during multiple phases over the past 100,000 years.

See A.H. Ivester et al, 2004. The timing of Carolina bay and inland dune activity on the Atlantic Coastal Plain of Georgia and South Carolina. Geological Society of America Abstracts with Programs 36(5):69

Aerial Photograph of Carolina Bays

But also on p. 127 of The Book, the following statement is presented: “All of the evidence fits our theory that the rims and bays formed all at the same instant [i.e., by an “extraterrestrial event” at around 12.9k]. In support of that, Ivester and coworkers (2003) dated two bay rims to 11,300 and 12,630 years ago using OSL… We used the same technique to date two levels of…Bay rim sand… the [OSL] Dating Laboratory at the University of Washington reported that the ‘highest age (11,400+/-6100 years) is close to the age of Clovis…’”

This passage contains so much misleading and misunderstood information that it is hard to know how to start sorting it out. Luminescence dating produces ages in calendar years, so OSL dates of 11,300 and 12,630 are too young for the “Event” at 12.9k. The mean of the date determined by the Impact Team at UW is far too young for the “Event” but, moreover, is absolutely meaningless given that the standard deviation is over 50% of the mean age! But the grossest distortion is the reference to the work of Ivester et al. In that paper, they clearly state that they are looking at multiple rims formed around some Bays. “Four concentric rims along the margin of one Bay… selected for dating have ages of 35,660+ or -2600; 25,210+ or -1900; 11,160+ or -900; and 2,150+ or -300 years ago…The trend of younger sand rims toward the bay center indicates that the bay has shrunk in area over the last 36,000 years… An additional date of 20,390+ or -1600 years documents eolian reworking of sediment associated with an adjacent bay to the southwest. Another new luminescence date from the Carolina bay rim bordering Arabia Bay in southern Georgia shows the rim was active 12,630+ or -1000 years ago. These dates indicate bay rims were periodically active well after the maximum advance of the Wisconsin ice sheet.” A rather remarkable twisting of words. The dates cited by Ivester et al. clearly do not pertain to the initial formation of any Bay.

See A.H. Ivester et al, 2004. Concentric sand rims document the evolution of a Carolina Bay in the middle coastal plain of South Carolina. Geological Society of America Abstracts with Programs 35(6):169
The Paleoindian archaeological record in the southeastern U.S. is described as “well dated” (p. 113), and I knew that not to be the case. Some components are reasonably well dated, but the older Paleoindian occupations such as Clovis (and Clovis archaeology was an important part of the story) are not dated at all.

The book further claims (p. 113) that “in the Southeast, well-dated [Paleoindian] sites provide good evidence for continuous occupation.” That is simply not true. Further, they quote archaeologist Al Goodyear as saying (p. 113) “… I’m noticing a big drop in the incidence of spear points dating from right after that time” (13,000 years ago). In actuality, numerical age control for post-Clovis Paleoindian artifact styles is almost non-existent.

In looking at the stratigraphy at the Clovis site, they claim that “18 inches” above the “Event” zone is a ledge “jammed with spears, tools, and bone.” (p. 73). I’ve spent a lot of time at the Clovis site, much of it involving stratigraphic work. I know of no such “ledge.” Further, “no humans had visited Blackwater Draw for more than 1000 years” (p. 73). There is simply no evidence for that claim whatsoever. The considerable work at the site by my colleague C.V. Haynes apparently was ignored.

After simply paging through the book and seeing all this twisting of scientific data, distortions of scientific fact, and facts easily verified in the published scientific literature, my skepticism began to emerge


In the Fall of 2007, a summary article by Firestone et al. was published in PNAS.

Firestone, R.B., A. West, J. P. Kennett & 23 co-authors, 2007. Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. Proceedings of the National Academy of Sciences 104:16016-16021.

This paper remains the key source in this entire debate because it comes closest to a comprehensive statement of the hypothesis concerning the “YDB” layer (Younger Dryas Boundary). But after reading it, I noted more problems of “facts” and data.

p.16016 (opening sentence of paper): “A carbon-rich black layer, dating to 12.9 ka (12,900 calendar years B.P.)… has been identified by C. V. Haynes, Jr…. at 50 sites across North America as black mats, carbonaceous silts, or dark organic clays…. The age of the base of this black layer coincides with the abrupt onset of Younger Dryas (YD) cooling.”

But a quick glance at the radiocarbon dates in Table 1 of Haynes’ paper shows that base dates for this zone vary widely.

p.16017: “Ten Clovis and equivalent-age sites were selected because of their long-established archeological and paleontological significance, and, hence, most are well documented and dated by previous researchers.”

In fact, very few of these sites could be considered to have “long-established archeological and paleontological significance.”

– The Clovis site and Murray Springs are arguably the only two.

– Morley has no archaeological or paleontological significance

– For Topper the archaeological data are only now emerging.

– Daisey Cave is an important archaeological site, but as indicated in the SI, was not occupied
before 11.5ka

– Gainey is probably an important site, but is poorly published.

– Chobot is very poorly published

– Lake Hind has minimal archaeological significance, no paleontological significance, and is poorly known.

P. 16019: “The YDB at the 10 Clovis- and equivalent-age sites has been well dated to 12.9 ka.“

This is a key point because the hypothesis fundamentally rests on a demonstration that the layers in question with the purported impact markers are all of exactly the same age, or at least as close to “exactly” as modern numerical dating methods (chiefly radiocarbon) can get. But in fact few of the layers are “well dated to 12.9 ka.” (This is clearly indicated in the SI to the PNAS paper). The North American sites are:

– Murray Springs, AZ

– Blackwater Draw, NM No dates directly linked to sampled section

– Daisey Cave, CA

– Wally’s Beach, Alberta “None of the Paleoindian points recovered was in situ and therefore it is not possible to directly link the points with the [dated] faunal remains” (Kooyman et al. 2001 American Antiquity, 687).

– Gainey, MI No Black Mat, no dates, no obvious indication of a 12.9ka level

– Topper, SC No Black Mat and no dates

– Chobbot, Alberta No dates

– Lake Hind, Manitoba

– Morley, Alberta No dates

– 15 Carolina Bays No dates

To summarize: 1) Several of these sites are “dated” by presence of Clovis artifacts, but that provides no precise indication of the 12.9ka level because the Clovis occupation was at least several centuries long. So using the archaeology as an age indicator, given the necessity for precise dating, is circular reasoning. 2) Five of the nine sites (over 50%) have no numerical age control whatsoever or no direct numerical age control on the YDB layers; no age control of any kind is reported for the 15 Carolina Bays (0%).

Firestone et al. (200) PNAS, Figure 1 (Link)

p. 16017: “Each of the 10 Clovis-age sites displays a YDB layer (average thickness of 3 cm).”

This is impossible to verify because sampling intervals and stratigraphic descriptions have never been provided. The comment that the average thickness of the “YDB layer” is 3 cm is significant in light of subsequent critiques of sampling by others (see below). As of June, 2011, the raw data for all samples have yet to become available despite requests to Allen West and Jim Kennett.

p. 16017: “We further suggest that the catastrophic effects of this ET event and associated biomass burning led to abrupt YD cooling, contributed to the late Pleistocene megafaunal extinction, promoted human cultural changes, and led to immediate decline in some post-Clovis human populations.”

The extinction issue is very complicated, and in fact no recently published data shows a synchronous extinction. At the recent (2010) AMQUA meetings, Russ Graham and Tom Stafford (who has also co-authored with some of the Impact proponents) presented a paper with the latest radiocarbon dates showing that most fauna was gone by 12.9k and that some mammoth survived after 12.9. And there is also the work of Gill et al. (2010) showing that mammoth and other herbivores in the Midwest were on the decline long before 12.9k (and that work followed other work in the Northeast showing the same thing [e.g., Robinson et al, 2009]).

Jacquelyn L. Gill, John W. Williams, Stephen T. Jackson, Katherine B. Lininger, Guy S. Robinson, 2009. “Pleistocene Megafaunal Collapse, Novel Plant Communities, and Enhanced Fire Regimes in North America” Science 326:1100-1103.

G. S. Robinson, L. P. Burney, D. A. Burney, 2005 “Landscape Paleoecology and Megafaunal Extinction in Southeastern New York State” Ecological Monographs 75, 295-315

Moreover, the reference to post-Clovis human population decline is based on a two-page paper on Redstone artifacts, which as indicated above are presumed to be post-Clovis in age (Goodyear, 2006), but in fact are not dated at all. A detailed look at the Paleoindian archaeological record provides no evidence for a population decline.

Vance T. Holliday and David J. Meltzer “The 12.9ka Impact Hypothesis and North American Paleoindians” Current Anthropology. V 51, p. 575-585

David J. Meltzer and Vance T. Holliday, “Response to comments on ‘The 12.9ka Impact Hypothesis and North American Paleoindians’” Current Anthropology.
p. 16018: “Charcoal displays peaks in the YDB at eight of nine Clovis-age sites and is present in 15 of 15 Bays, reaching peaks in four Bays with paleosols.”

And from the Supplemental Information: “The Bays have poorly stratified, sandy, elevated rims (up to 7 m) that often are higher to the southeast. All of the Bay rims examined were found to have, throughout their entire 1.5- to 5-m sandy rims, a typical assemblage of YDB markers (magnetic grains, magnetic microspherules, Ir, charcoal, soot, glass-like carbon, nanodiamonds, carbon spherules, and fullerenes with 3He).”

The sandy Bay rims are described as “poorly stratified” and yet some have “buried paleosols.” Which is it? And all Bay rims sampled have YDB markers throughout, including, presumably, the buried soils? What does that mean? The Bay rims can’t be used as evidence if they contain no discrete impact marker layer. The comment suggests that YDB markers can be found outside of discrete contexts, negating their significance.

p. 16019: “At Murray Springs, Haynes… first reported the presence of glass-like or ‘vitreous’ carbon in the black mat. In addition, he chemically analyzed the black mat layer, concluding that it most likely resulted from the decomposition of charred wood and/or a prolonged algal bloom, both of which could result from event-related processes (e.g., climate change and biomass burning). Some black mats have no algal component, only charcoal.”

Haynes clearly describes the black mat as an algal layer (and this is so stated in the SI to the 2007 PNAS paper). How does an algal bloom result from “event-related processes”? Algal blooms occur all the time on the Earth’s surface and almost all in the absence of any extraterrestrial event.

p. 16020: “if multiple 2-km objects struck the 2-km-thick Laurentide Ice Sheet at <30°, they may have left negligible traces after deglaciation… [perhaps] limited to enigmatic depressions or disturbances in the Canadian Shield (e.g., under the Great Lakes or Hudson Bay)”

An obvious flaw with that speculation is that, by 12,900 years ago, only the Lake Superior basin was still under glacial ice, a fact well-known and documented for decades.

Dyke, et al., 2003. Geological Survey of Canada, Open file 1574

16021: “For humans, major adaptive shifts are evident at 12.9 ka, along with an inferred population decline, as subsistence strategies changed because of dramatic ecological change and the extinction, reduction, and displacement of key prey species.”

This was news to me and to any other Paleoindian specialist. But sometimes you don’t see what you are not looking for, so several of us revisited to the Paleoindian literature so see if these claims could have any merit. As noted above, this notion was initially based on Paleoindian artifact data from the Southeast U.S. This was a surprise because there is almost no good stratigraphic or radiocarbon record for Paleoindian archaeology in that region. Much of our work has been on the Great Plains, which has the best dated regional stratigraphic record of Paleoindian occupation in North America, so we decided to test the hypothesis with data from the Great Plains. We see no evidence of any sort of occupation hiatus at 12.9ka. The end of the Clovis point style tells us nothing about an impact, and in any case the style persists after 12.9ka. Arguments that stratified sites with a post-Clovis occupation hiatus misstate the archaeological and geological records. At sites with multiple Paleoindian occupations, “sterile” layers between occupation zones are the norm, whether they separate Clovis from Folsom zones, Folsom from other Folsom occupations, or any combination of occupations you care to mention. Moreover, out of >150 Paleoindian sites we looked at in the literature, over two-thirds are single occupation sites (see below). So whether they are Clovis, Folsom, or late Paleoindian features, there is no occupation above. Absence of a post-Clovis occupation is not a mysterious “hiatus,” it is the norm at most Paleoindian sites.

Another general question about the data from impact markers in the PNAS paper: Why the multiple peaks among the various indicators? e.g., double carbon spherule and double charcoal peaks at Chobot; the magnetic grain and spherule peak higher than the main carbon spherule peak at Chobot; two Iridium peaks and one carbon spherule peak matching neither Ir peak at Lake Hind; and a variety of spikes that don’t match up at Topper. How exactly did that happen? A single “event” should sprinkle its traces across the continent at the same time (the proponents make this point over and over). Yet they rarely occur together in the sites. I know of no sedimentological or weathering process that could so discretely vertically sort the various indicators.

To date (October, 2010), the 2006 book and the 2007 PNAS paper are the most comprehensive arguments in support of a YD Impact. Significantly, none of the authors is a specialist in late Quaternary terrestrial geology or biology nor in Paleoindian archaeology.


In 2008 and 2009 a series of papers came out, directly contradicting several implications of the PNAS paper. These skeptical papers were written by a wide array of scientists from different disciplines who are leaders in their respective fields and who, for the most part, worked independently of one another.

Nicolas Pinter and Scott E. Ishman, 2008. Impacts, mega-tsunami, and other extraordinary claims.” GSA Today, 18(1) 37-38.

The first critical paper was written before the PNAS paper came out and published just a few months later. Pinter and Ishman (January, 2008) published a brief paper in GSA Today and took issue with The Book by Firestone et al, along with a series of meeting abstracts. They were the first to note that magnetic grains and in particular magnetic microspherules are everywhere on the Earth’s surface and throughout the geologic record. They were also the first to point out problems linking both megamammal extinctions and the “black mat” with some sort of 12.9k years BP “extraterrestrial event.”

Briggs Buchanan, Mark Collard, and K. Edinborough. 2008. “Paleoindian demography and the extraterrestrial hypothesis.” Proceedings of the National Academy of Sciences 105:11651-11654.

Buchanan and colleagues used the frequency of radiocarbon dates from archaeological sites as a proxy for population and concluded that there was no population “gap” just after 12.,9k I don’t believe that numbers of radiocarbon dates tell us much, if anything, about populations; too many variables of preservation, visibility, and sampling come in to play. Nevertheless, the authors see no gaps, so there were people around.

Marlon, J. P. J. Bartlein, M. K. Walsh, S. P. Harrison, K. J. Brown, M. E. Edwards, P. E. Higuera, M. J. Power, R. S. Anderson, C. Briles, A. Brunelle, C. Carcaillet, M. Daniels, F. S. Hu, M. Lavoie, C. Long, T. Minckley, P. J. H. Richard, A. C. Scott, D. S. Shafer, W. Tinner, C. E. Umbanhowar, and C. Whitlock. 2009. Wildfire responses to abrupt climate change in North America.Proceedings of the National Academy of Sciences 106:2519-2524.

This paper dealt with other issues besides The Impact, but the researchers did look to see if they saw any charcoal spikes dating to 12.9ka in lake cores, which is something predicted by The Impact Hypothesis. They saw no evidence for the predicted charcoal layer (see discussion of 2010 AMQUA meeting, below).

More papers followed in later 2009 and in 2010.

Todd Surovell, Vance Holliday, Joseph Gingerich, Caroline Ketron, C Vance Haynes, Ilene Hilman, Daniel Wagner, Eileen Johnson, Phillippe Claeys, 2009 “An Independent Evaluation of the Younger Dryas Extraterrestrial Impact Hypothesis” Proceedings of the National Academy of Sciences v. 106, p. 18155-18158.

An attempt was made to reproduce the evidence for an impact by analyzing samples for magnetic grains and magnetic microspherules. The samples came from several sites reported in the original 2007 PNAS paper (Blackwater and Topper) plus a number of other dated stratigraphic sequences that contained sediments dating to 12.9k. In all cases, no peaks in grains or spheres were detected.

François S. Paquay, Steven Goderis, Greg Ravizza, Frank Vanhaecke, Matthew Boyd, Todd Surovell, Vance T. Holliday, C. Vance Haynes, Philippe Claeys, 2009 “Absence of geochemical evidence for an impact event at the Bølling–Allerød/Younger Dryas transition” Proceedings of the National Academy of Sciences, v. 106, p. 21505-21510.

These investigators attempted to reproduce the Iridium spikes reported in the 2007 PNAS paper (and also looked for other Platinum Group Elements) at five sites in North America investigated by Firestone et al (2007) plus other sites. They found no indicators of an impact.

Jacquelyn L. Gill, John W. Williams, Stephen T. Jackson, Katherine B. Lininger, Guy S. Robinson, 2009. “Pleistocene Megafaunal Collapse, Novel Plant Communities, and Enhanced Fire Regimes in North America” Science 326:1100-1103

This paper deals with the extinction issue rather than the YD Impact per se. But it shows that overall, mega-herbivores declined significantly long before 12.9ka.

Haynes, C.V., Jr., Boerner, J., Domanik, K., Lauretta, D., Ballenger, J., Goreva, J., 2010. The Murray Springs Clovis site, Pleistocene extinction, and the question of extraterrestrial impactPNAS 107, 4010-4015.

This paper was an attempt to reproduce data published by the Impact Team for magnetic grains, magnetic microspherules, and Iridium.

David J. Meltzer and Vance T. Holliday, 2010 “Would North American Paleoindians have noticed Younger Dryas age climate changes?” Journal of World Prehistory, v 23, p 1-41.

This paper did not focus directly on the Impact hypotheses but was a broader look at the Younger Dryas, primarily on the Great Plains. The paper showed that environmental changes in the terminal Pleistocene varied in timing, degree, and direction. There was no synchronous, continent-wide climate change toward significant cooling at 12.9ka. Further, some Clovis sites are younger than the hypothesized Impact Event.

Modified from Holliday & Meltzer, 2010, Current Anthropology, v 51, pp. 575-584, Figure 1.

Scott, A.C., Pinter, N., Collinson, M.E., Hardiman, M., Anderson, R.S., Brain, A.P.R., Smith, S.Y., Marone, F., Stampanoni, M., 2010. Fungus, not comet or catastrophe, accounts for carbonaceous spherules in the Younger Dryas ‘impact layer’. Geophysical Research Letters 37, L14302, doi:10.1029/2010GL043345.

This paper suggested that the carbon spheres reported by The Impact Team are not high-temperature, impact particles, but rather were indistinguishable from low temperature, buried fungal byproducts (fungal sclerotia). They also failed to reproduce a C14 sequence reported by The Impact Team from Arlington Springs, California (a key site for The Impact Team).

There have been several responses to these papers by The Impact Team. They published a variety of claims concerning Paleoindian archaeology and dating in a series of comments on Buchanan et al., but most are misguided:

Archaeological sites containing both Clovis and immediately post-Clovis material are rare… Of the 11 well-dated credible Clovis sites [Waters and Stafford, 2007], none has post-Clovis materials immediately above, suggesting a potential disruption in settlement or landscape use”

(Kennett and West, 2008, comment p. E110)

This is true, BUT most Paleoindian sites are single-component sites, i.e., just one feature; nothing below or above and this applies at non-Clovis sites as well. Out of ~150 published accounts of buried, intact sites, Holliday & Meltzer (2010, Figure 2, Supplemental data table) document fully 2/3 are single component

Modified from Holliday & Meltzer, 2010, Current Anthropology, v 51, pp. 575-584, Figure 2.

They claim that at the Clovis site (Blackwater Draw): Folsom-age materials occur above the Clovis materials but a hiatus of ~500 years is suggested by an intervening sterile deposit (10-35 cm) and radiocarbon ages of 12.4-11.8 ka. (Kennett and West, 2008, comment p. E110).

This is wrong. In the section they examined on the “South Bank,” there are no Clovis or other archaeological features. The nearest feature, as far as records allow, was ~20 m distant (Holliday and Meltzer, 2010…

A series of assertions are made by D.J Kennett, Stafford & Southon (2008, E107):

1) Only 14C dates with measurement precisions <100 years, and preferably <60 years, should be used because larger error margins blur probability distributions; many dates had precisions from 200 years to >2,000 years.

Yes, this would be ideal, but none of the sites used in the 2007 PNAS nor those in Kennett et al. 2009a,b meet these criteria either.

Kennett, D.J., Kennett, J.P., West, A., Mercer, C., Que Hee, S.S., Bement, L., Bunch, T.E., Sellers, M., Wolbach, W.S., 2009a. Nanodiamonds in the Younger Dryas boundary sediment layer. Science 323, 94.

Kennett, D.J. Kennett, J.P., West, A., West, C.J., Bunch, T.E., and 12 others, 2009b. Shock-synthesized hexagonal diamonds in Younger Dryas boundary sediments. PNAS 106, 12623-12638.

2) Only bone dates processed with modern techniques [e.g., XAD… or ultrafiltration…] are valid because of the catastrophic consequences of poor chemical preparation…

True, but dateable bone is not easy to find in many Paleoindian sites and, again, none of the sites used in the 2007 PNAS nor those in Kennett et al 2009a,b met these criteria.

3) Stratigraphic associations between radiocarbon dates and cultural residues need to be demonstrated; e.g., much of the purported pre-11,000 14C years evidence used is now discredited.

The authors provide no support for this claim. Discredited by whom? Dates on charcoal or wood considered valid before the development of AMS-purified collagen dating are still as valid now as when they were assayed.
4) Single-component sites do not have the same credibility as multiple-occupation sites.

The sites dated by Waters & Stafford (who the Impact Team use to support some of their claims; and Stafford is one of the commentators!) include the following single-component sites: Lange-Ferguson, Anzick, Dent, Paleo Crossing, Domebo, Lehner, Shawnee Minisink, Murray Springs, Colby (of the “top” 11 sites in Waters & Stafford’s work), East Wenatchee (of the 17 “top” sites), and Wallys Beach and UP (of the top 24).
5) The potential for site discovery is not equal through time; destruction and preservation vary by region and are determined by burial depth, depositional environment, ground water geochemistry, and site type (e.g., kill, processing, or camp).

No disagreement there, but what is the point?

Kennett et al (2008, E107) conclude their comments by noting: Much more archaeological and chronological work is required to test the YDB extraterrestrial impact hypothesis. That is true for the tests by critics only if it also true for the proponents. And nowhere do they concede that more testing of the YD hypothesis is necessary to confirm it.

The authors of the original paper then published a response:

Collard, Mark, Briggs Buchanan, and K. Edinborough 2008. Reply to Anderson et al., Jones, Kennett and West, Culleton, and Kennett et al: Further evidence against the extraterrestrial impact hypothesis. PNAS 105:E112-114.

The Impact Team published no commentary on the charcoal work by Marlon et al (2009). But on the internet the word was out that Allen West has thirty some additional datasets, and The Impact Team is writing a response paper that includes these [the new cores] along with various criticisms of their chronological and statistical approach. (Email from D. Kennett to D. Meltzer, 17 Feb 2010)

Apparently the large team of charcoal and lake coring specialists somehow “missed” over 30 cores that Allen West learned about and gained access to. And The Impact Team is somehow better equipped and better trained to interpret these new cores. In any case, almost two years after Marlon et al was published, we’ve seen no formal response, except at the 2010 AMQUA meetings (see below).

In response to the work of Haynes et al. at Murray Springs, Firestone et al. (2010) noted that Haynes et al reported extremely high concentrations of Ir ranging from 31 to 64 ppb in two magnetic fractions across the YDB. They [Haynes et al] also note a peak in magnetic grains from the Clovis-age surface.

Firestone, R.B., A. West, T. Bunch, 2010. Confirmation of the Younger Dryas boundary (YDB) data at Murray Springs, AZ. PNAS v. 107, E105.

Haynes et al (2010) responded We consider our iridium analytical results of 64 ppb and 31 ppb to not be anomalous because they are less than the 72 ppb for magnetics from the modern stream bed. Regarding the magnetics, Haynes told West when he first collected at the site that magnetic grains are ubiquitous in the late Quaternary alluvium in and around the site and their local abundances are quite variable.

So over and over we see misstatements of fact and repeated accusations that everyone else attempting but failing to confirm their hypotheses or to reproducing their results must be incompetent.

No formal commentary was published on the work of Surovell et al. in trying to reproduce the magnetic grain and magnetic microspherule data. But pot-shots appeared, including a feature story in the archaeology news magazine The Mammoth Trumpet (April, 2010, v 25, n 2) and in an unreviewed article by Firestone.

In The Mammoth Trumpet (pp. 16-17), [Allen West claimed] “I believe they had good intentions, but simply failed to follow our protocol in adequate detail.” He explains that because the markers are so tiny, proper protocols must be strictly followed to produce meaningful results. “Only scientists who have previously searched for trace materials would find our protocol clearly understandable,” he says, “and to my knowledge, none of the Surovell group has ever worked with trace materials before. I don’t believe they understood the need for carefully following the directions, and felt the changes were inconsequential.”

These comments and others in the article are remarkably condescending. Further, The Impact Team seems to be saying that only they know how to get the results they want! Is that science???.

Similar comments about the work of Surovell et al., plus various other themes that keep coming up from The Impact Team (e.g., cherry picking data that suit their arguments) are on display in a paper by Firestone inJournal of Cosmology (2009, v.2, p. 256-265). This journal is a non-peer-reviewed, on-line journal.

Figure 3 in the J. of Cosmology paper suggested that there are ~15 basins scattered across the southern half of the Great Plains that all line up in directions that lead back to supposed impact sites in the Great Lakes. What isn’t mentioned is that there are thousands of small circular to elliptical basins scattered throughout this region; over 20,000 in northwest Texas and eastern New Mexico alone (Sabin & Holliday, 1995, Annals of the Assoc of American Geographers). They are randomly oriented. Fifteen basins can easily be picked out oriented in any direction one chooses.

Firestone also comes back to the Carolina Bays to make an argument that they are the result of impact from debris of a primary extraterrestrial impact in the Great Lakes area. He attempts to contradict work that shows the basins to be much older than 12.9ka (as discussed above) by impugning the dating results on sand rims around the basins: Older OSL dates at Bays studied by Invester et al. (2007), Firestone suggests, may reflect inadvertent sampling of underlying, older sediment that may have shifted over time. Though, as noted, he embraced Ivester’s work (and distorted it) in The Cycle of Cosmic Catastrophes. Moreover, he here resorts to dismissing the work as some sort of incompetence.

Further, in a comment on the work by Surovell et al. (2009), he asserts: The YDB layer deposited at many sites across North America is only a few mm thick. Turbation by wind and water can destroy the YDB layer, change its position with respect to the YDB, or even split it into multiple thin layers. At about 20% of sites no evidence of the YDB layer remained. But this process of “splitting of the YDB” is never explained. I know of no such post-depositional process that can pick out specific microscopic indicators and move them up or down. Some soil-forming processes can move clay down and form “bands” but that is the only remotely similar process I know of. What could selectively move nanodiamonds in one direction and microspherules in another???

And: Tedious microstratigraphy is required to find the YDB impact layer which was often <2-3 mm wide. No such tedious microstratigraphic field work as ever been reported much less described by The Impact Team. They go to sites and simply sample where local experts tell them that the 12.9ka layer should be. How can they or anyone else know that such layers are so thin? They never documented this in any paper they published. Indeed, as mentioned above, the 2007 PNAS paper (p. 16017) notes that: Each of the 10 Clovis-age sites displays a YDB layer (average thickness of 3 cm). So is it 3cm or 3mm?

And: Broad sampling intervals near the YD layer used by Surovell et al. (2009) have diluted their results considerably. This argument played out over the internet after Surovell et al. (2009) was published. This is a red herring. Before our sampling, The Impact team said that the average thickness of the “YDB layer” is 3 cm, but nowhere are the sampling intervals published or available – I asked both Allan West and Jim Kennett and neither responded. Some of Surovell’s samples were thicker than 3 cm, some about 3 cm, some less. The amount of magnetic microspheres is as much as an order of magnitude higher than any other samples in the reported sections. How can anyone sample a zone maybe twice or three times as thick as The Impact Team did and “dilute” the spike so it couldn’t be seen? Not possible. Moreover, they report near- zero levels of spheres above and below the 12.9ka level. How could we collect more sample with near- zero levels of spheres and dilute it such that we found more spheres than they did? Maybe Surovell was creating matter with his lab methods! That’d get him untold wealth and he could tell all of us to go to Hell!

They [ Surovell et al.] also selectively searched for highly spherical shiny microspherules thus excluding the dull, less spherical, and often pitted microspherules that we reported.

Highly spherical, shiny microspherules were sought out because that is exactly what is described as “typical” in the lab methods with the 2007 PNAS paper!

The Impact Team has increasingly focused their attention on nanodiamonds as the smoking gun for an impact. They published an article on recovery of nanodiamonds in the Greenland ice sheet:

Andrei V. KURBATOV, et al., 2010. “Discovery of a nanodiamond-rich layer in the Greenland ice sheet” Journal of Glaciology, Vol. 56, No. 199, 2010 749-759.

They apparently found a dense layer of nanodiamonds (walked right to it according to NOVA) but failed to date it.

But the notion of nanodiamonds as a smoking gun for an impact has been challenged. Tyrone L. Daulton, Nicholas Pinter, and Andrew C. Scott (PNAS September 14, 2010 vol. 107 no. 37 16043–16047) present data suggesting that the materials identified as nanodiamonds are in fact terrestrial forms of carbon. Further support for this idea is provided by:

H. Tian, D. Schryvers, and Ph. Claeys, 2011. PNAS, v. 108 no. 1, pp. 40-44. “Nanodiamonds do not provide unique evidence for a Younger Dryas impact”

This caused a stir among The Impact Team. In a typical reaction, they called the study “fundamentally flawed science” (Nature on-line, 31 August 2010 | doi:10.1038/news.2010.441) and complaints about Daulton et al. focus on sampling, sample processing, and interpretation. Impact proponents level similar criticisms at other outside studies of traces of impact and fire. Kennett sees little evidence that Daulton and his colleagues actually sampled the YDB, an often thin and sometimes hard-to-recognize layer.“There’s been a real problem of data quality,” Kennett sums up. (2010 vol 329 Science p. 1141).

So once again the skeptics failed to find the thin and sometimes hard-to-recognize layer.… but the Impact Team never explained how they themselves found it. And, of course, the skeptics are incompetent.

One of the arguments used to support the Impact Hypothesis is evidence for cratering in the Great Lakes basin. In the Journal of Siberian Federal University: Engineering & Technologies , Firestone et al. (2010) state that “if multiple 2-km objects struck the 2-km-thick Laurentide Ice Sheet at <30°, they may have left negligible traces after deglaciation… [perhaps] limited to enigmatic depressions or disturbances in the Canadian Shield (e.g., under the Great Lakes or Hudson Bay)” (Firestone et al. 2007:16020). An obvious flaw with that speculation is that by 12,900 years ago only the Lake Superior basin was still under glacial ice (Dyke et al. 2003) (sSee map above). They now suggest “deep holes” beneath four of the Great Lakes could represent impact craters (Firestone et al. 2010:57-58). They dismiss the possibility that these holes were the result of glacial erosion, citing the latest edition of Dawson’s Acadian Geology, a book published more than a century ago (Dawson 1891). Evidently, they believe subsequent generations of glacial and Quaternary geologists working in the Great Lakes failed to notice the holes’ extraterrestrial origin. Yet, if these holes were caused by an impact 12,900 years ago (and they provide no evidence the holes are that old), it is curious that the impacts produced elongated craters at different orientations, yet each one parallel to local ice flow in the up-ice end of its lake basin.


David Meltzer and I presented the archaeological and geoarchaeological record proving no evidence for a “catastrophic demographic collapse” (i.e., the end of the Clovis occupation) in North America. The Impact Hypothesis provides an extraterrestrial answer for an archaeological problem that does not exist.

Vance T. Holliday and David J. Meltzer “The 12.9ka Impact Hypothesis and North American Paleoindians” Current Anthropology, v. 51, p. 575-585

David J. Meltzer and Vance T. Holliday, “Response to comments on ‘The 12.9ka Impact Hypothesis and North American Paleoindians’” Current Anthropology, v. 51, p. 599-602


As noted earlier, samples I collected at Lubbock Lake in the Fall of 2007 were sent to both Todd Surovell and to Jim Kennett. By the Fall of 2009 Kennett and his team completed their analysis. As of May, 2011, I can not reveal the results of the test, at the request of Jim Kennett. Suffice to say, the results (for recovery of magnetic microspheres and also nanodiamonds) did not meet the expectations of the Impact Team. The immediate response was to 1) question my sampling and labeling (I double checked the samples and based on my 25+ years working at Lubbock Lake confirmed that samples were correctly identified and labeled in th field); question my understanding of the site microstratigraphy; and question the dating (but this never came up before I sampled or before they got the results they didn’t like). The obvious more obvious issue – never raised by The Impact Team – is that there is a problem with their hypothesis! I hope the results will soon get published. In the meantime, Jim Kennett and I agreed to resample the section at Lubbock Lake. Making arrangements for this dragged on until publication of a piece by Rex Dalton in the magazine Miller-McCune(see link at end of this story). We finally re-sampled in May, 2011. Stay tuned….

AMQUA 2010

As of this writing (March, 2011), the culmination of the debate over the Clovis Impact Hypothesis was at the biennial meeting of the American Quaternary Association, held in Laramie, WY, in August, 2010. The meeting organizers invited three members of The Impact Team and three of the skeptics to present their cases, followed by an open Q&A session. The representatives of The Impact Team were James Kennett, Allen West, and Ted Bunch. The skeptics were Nicholas Pinter, Todd Surovell, and Mark Boslough.

Both sides gave it their best shot, I suppose. The Impact Team made some good points and had some interesting new data. But these data were not published and simply dropped on the skeptics and the audience with no real opportunity to digest it. The skeptics pointed out the flaws in logic in the impact argument, the lack of reproducibility of all previous impact data by independent groups, and distortions of other people’s data. For example, the work on charcoal and fire history from lake cores published by Jennifer Marlon et al. in PNAS in 2009 was criticized and then statistically “massaged” (though the statistical maneuvering was never described) to show that in fact there are charcoal peaks at 12.9k in the lake cores. One of the co-authors happened to be in the audience, however, and pointed out that visual and microscopic examination of the core showed no evidence for a charcoal spike. The Impact Team simply ignored the crux of the argument (the absence of charcoal in field samples).

One of the skeptics showed how the various aspects of the impact story kept changing as their story came under attack. In particular, he showed how the lab protocols for extracting magnetic grains and magnetic microspherules changed after a paper was published showing how the spherule data could not be reproduced. He showed a photo from the Firestone et al 2007 PNAS paper and protocols with “typical spherules” – nice little shiny ball bearings. Then he showed a photo of “typical spherules” from the protocols they sent out after Surovell et al. was published in PNAS in 2009. The typical spheres were all kinds of irregular little blobs. There was an audible gasp in the audience when he showed that slide.

When Alan West was up, he attempted to show where Todd went wrong with his protocols for extracting spherules. He had several PowerPoint slides devoted to showing how the little spheres would settle out of a sample bag, so if Todd (or anyone else) didn’t shake the bag, they’d get an undercount. If West actually tested this mechanism, he showed no evidence of those tests. So this whole debate revolves around proper shaking of a sample bag? Anyone who has worked with sediment samples in a lab is routinely moving them and usually shaking them and is careful sampling to get a representative sample. So will the next edition of lab protocols discuss proper bag shaking? How many times is enough? 3? 17? Is that up and down or side to side? Can you turn the bag over while shaking? Or between shakes?

When questioned about the work of Richard Firestone, all three proponents of the Impact hypothesis scrambled to disassociate themselves from him. “Rick is out there on his own” one of them was heard to say. And “He is going his own way.” (Though I note that just this year Allen West was publishing with Firestone in the Journal of Siberian Federal University: Engineering & Technologies (Firestone et al. 2010), as noted above.

So it goes…

Nic Pinter, who co-authored the first critique of the Impact Hypothesis (2007, noted above), also co-authored an exceptionally thorough review, summarizing over 3 years of debate, claim, and counter-arguments.

Nicholas Pinter, Andrew C. Scott, Tyrone L. Daulton, Andrew Podoll, Christian Koeberl, R. Scott Anderson, Scott E. Ishman, 2011. The Younger Dryas impact hypothesis: A requiem. Earth-Science Reviews, doi:10.1016/j.earscirev.2011.02.005

This “requiem” is well-titled. Though some proponents of the Clovis Impact Hypothesis will not be deterred, most objective readers will likely realize that the case supporting the hypothesis was a house of cards.

Key point: No comprehensive statement on the YD Impact hypothesis has been published in a peer-reviewed venue by the proponents. In response to criticisms of their work, lack of reproducibility of data, and failure to confirm their hypotheses, The Impact Team invariably ends up accusing all others (largely an array of specialists in their respective fields, and most working independently) of incompetence.

Was there an “extraterrestrial event” somewhere on or above North America at 12.9k years BP? I have no idea. Ultimately, I don’t care whether there was a 12.9k impact. I just want to know what was going on then. If there was, I see no reason to believe – at this point – that it had an impact on people, flora, fauna, or climate. We could be dealing with an extraterrestrial impact that had no terrestrial impact!

Just because an hypothesis is outrageous doesn’t make it true.
Also, for further reading, see Rex Dalton’s article in Miller-McCune. (link)

(Thanks to Nicholas Pinter for his comments on this personal narrative).

33 Responses

  1. I am very impressed by this convincing critical review, with its calm, quietly earnest citation of many streams of evidence.

    Are there actually any convincing lines of evidence to support any Holocene impact extinction hypothesis?

    Thank you, Vance Holliday.

  2. The problem with the Younger Dryas and the YD and Holocene impact hypothesis is hydrogeological, and not paleontological.

    Most of us working and thinking critically on this problem from the hydrogeological perspective expect to have some more definitive data and answers sometime in the fall of this year. Paleontologists are the wrong people to be asking opinions on a problem that for the most part is almost purely geophysical.

  3. Hi VH –

    You left many things out of your summary.

    First off, Firestone et al were hardly the first people to look at cosmic impacts at the start of the Holocene. As a matter of fact, my own book “Man and Impact in the Americs” was simultaneous and independent of theirs, and actually appeared somewhat earlier. There were others who had much earlier hypothesized about it, but very very sloppily.

    While the timing I used in my book was rotten, Firestone had been dealing with that rottten 14C timing for a long time, which is what put him on to the event. Aside from that, I got that rotten timing from you archaeologists, and as a matter of fact I can blame all the errors in my own book on you, and do not hesitate to do so. In fact there is a whole chapter in “Man and Impact in the Americas” devoted to doing that.

    Its not that I dislike archaeologists becuse of my own frustrations in not becoming one, and I do understand the money constraints you work under, its simply that I get annoyed watching incompetent archaeologists waste what little money is available.

    If you yourself had any previous knowledge of the effects of other recent smaller cometary impacts, then Firesone et al’s hypothesis would not have appeared “outrageous” to you at first. That you did not know about those “smaller” cometary impacts and their effects is Ed Weiler and David Morrison’s fault. Ed Weiler needs to be fired; this year’s October pass of Comet 73P will be a good time to do it.

    How you’re going to deal with the other recent smaller impact events in the Americas which the First Peoples remembered is up to you. While you can try to rationalize it away, the impact hazard is real and massive. The strata for one of those events is not a mere 3 cm. thick. The Holocene start events directly take up about only about 5 to 9 pages in my own book.

    As far as how you handle the “outrageous” Native American peoples’ memories of this particular impact event, some of which have been set out here, you could simply read them as fossil legends, as Major did. The problem of course is the peoples repeated mention of very specific impact detail. If you don’t think that they were here then, then you need to come up with some alternative. If you want to try visitors from outer space or Lemurians, then there are a whole lot of folks like CL around.

    Don’t expect a warm welcome from the Elders if you do, though.

    In sum, The First Peoples remembered the YD events, and remembered where the were; thus NAGPRA issues will come to an end. As this is inevitable, might I suggest that you and other archaeologists learn to live with this, instead of trying to delay it?

    The Assiniboine account which Dennis grafitied here will end up being a type case for this process. The recently found Pacific coast island tool kit can be traced from Japan to there, and thence to the glacial lakes. Given that, Kennewick was most likely a Nakota ancerstor, and the Nakota account can be used to try to locate one of the larger impacts that took place at that time.

    (F*** you, Dennis, go burn in the desert. Yes Rich, there are convincing lines. Read the First Peoples memories here. Read the lithic distribution study. There is also a global spike in 14C production. And simultaneous species extinction. Oh, by the way, tell Dennis to go f*** himself.)

    While we all appreciate rigor, VH, and I certainly have problems with both Firestone’s neutron production hypothesis and his injection mechanisms, do you really want to end up remembered for a quote like “Man will never fly. It is a scientific impossibility.”? You are well on your way to being remembered for “outrageous hypothesis”.

  4. Hi VH –

    By the way, a mastodon required 200 kilograms (400 pounds) of fodder a day. Without this, death follows.

    Comet dust loads are far more effective than volcanic dust in blocking sunlight.

    See the Assiniboine accounts for their memories of the YD nuclear winter.

    The surviving animals compete for what food remains.

  5. VH –

    I agree completely with you on both Firestone’s Great Lakes comments, and that teams misunderstanding of the Bays.

    As far as impact research goes, you need to remember that Firestone et al. are hardly “The Impact Team”; they simply are working on one particular impact; there are many others working on that event as well; there are other impact researchers working on other impacts. That he and his colleagues are the only team you know of speaks volumes; you seem puzzled by the appearance of other cores; they came from other impact researchers.

    Once again, other impact researchers are working on other impacts.

    As far as the consequences go, you need to understand that we are talking about real money here, not your typical archaeological budgets. NASA’s asteroid sample return mission will cost around $1,000,000,000; NASA’s first NEO space telescope will cost around $1,000,000,000.

    Whenever you cite 14C dates that were not properly calibrated in the first place, you are engaging in circular reasoning.

    In closing, I want to note that it took me several hours to type these initial comments – time which I could have better used here in the field.

    Finally, I’d like to note that many doctoral archaeologists could not knap a point, hunt a deer, dress it, and cook it, if their lives depended on it. Many of them can not find a lick or wallow.

    Since many people seem to need a large hole in the ground, let’s try to find one of them. If George will simply repost tha Assiniboine acounts I posted here earlier, I’ll walk you through the process, and we’ll try to find the glacial lake they were at at the YD.

    Are you familiar with western lithic sequences and their publication?

  6. Ed Said:
    “The Assiniboine account which Dennis graphitized here will end up being a type case for this process. The recently found Pacific coast island tool kit can be traced from Japan to there, and thence to the glacial lakes. Given that, Kennewick was most likely a Nakota ancerstor, and the Nakota account can be used to try to locate one of the larger impacts that took place at that time.
    (F*** you, Dennis, go burn in the desert. Yes Rich, there are convincing lines. Read the First Peoples memories here. Read the lithic distribution study. There is also a global spike in 14C production. And simultaneous species extinction. Oh, by the way, tell Dennis to go f*** himself.)”

    Brilliant use of the language Ed. If by “graphitized” you mean my assertion that you are a liar, a fraud, and a Velikovsky wannabe, with delusions of grandeur, who thinks he should be the dean of impact science, but without the academic credentials to justify such exalted status,  Yep! guilty as charged.
    If you want me to go away, and stay away. All you have to do is stop talking your small minded, and insulting, ad hominem shit. And leave me out of the conversation.

  7. Ed, earlier, you mentioned an Assiniboine report of a catastrophic glacial lake discharge flooding in the West. Was this related to a known lake? If so the name of that glacial lake could then be added to the list of glacial lakes with a known major discharge, simultaneous by the Grand Hypothesis (GH), with the (still hypothetical) YDR impact event, a list that now is comprised of three names: Iroquois, Chicago, Agassiz. Was Lake Missoula by any chance the Assiniboine reported lake?

    Any verification of GH would almost prove the YDR impact event was real, and it is to be stressed here that no credible causes are ever stated, in any online sources that I have looked at, for the catastrophic flooding events of the three lakes, but is is known that their dates were all very close to YDR boundary time. Has this been mentioned in any of the Firestone team papers? If not I would hate to claim credit for something so obvious and well-documented except for the simultaneity.

  8. you crazy old fart, my great grandma at 90 and almost died almost 35 years ago , never even heard of new ager you stupid as…..

  9. Chicken, what did I do? I haven’t replied to you in over a week or even longer!



  11. Hi Hermann –

    The problem is associating which western basin glacial lake was connected with the Assiniboine account. The distribution in the western basin of the tools cognate with the recently found Pacific coast toolkit should help to identify it.

    Then one could look for dates for the outwash, as well as the impact which released it. Since a lot of people need big holes, this should shut them up.

  12. CL –

    The problem isn’t with what your ancestors said, or my ancestors said.

    The problem is your confusion in understanding what they said and say.

    Since I suspect the source of your “Allegewi” nonsense is Ross Hamilton, let me be much more specific. Ross was working on the giants (“Allegewi”); so was Vine DeLoria and Pat Mason (T’sulgul).

    Pat and Vine graciously shared their materials with Ross; but when they found out how confused about the “Allegewi” he was, they cut him off.

    Once again, there were no “Allegewi”. “Ale/gehenny” means “pretty river”. “Talagewi” was the Lenape word for Cherokee and Shawnee.

    I want to see you forbidden to use the Tusk to promote your confusion and nu-age nonsense.

  13. “you mean my assertion that you are a liar, a fraud, and a Velikovsky wannabe, with delusions of grandeur, who thinks he should be the dean of impact science, but without the academic credentials to justify such exalted status, Yep! guilty as charged.”

    Dennis, given the length of time that features survive in the arid west, the features you are looking at could be from many time periods, and that they may be impact features and not something else.

    “If you want me to go away, and stay away. All you have to do is stop talking your small minded, and insulting, ad hominem shit. And leave me out of the conversation.”

    Dennis, there was nothing insulting in my initial posts to you. You are the one with the problem(s).

    Morrison still has not publicly stated that Mueller’s injection mechanism is wrong; and much more serioulsy he has done nothing to correct his earlier ELE estimates.

    Ed Weiler continues to try to duck his responsibilities, NASA’s responsibilities.

    Given your insults to me, you clearly lack juddgement and intellectual capacity. For these reasons I ask that you be barred from the Tusk.

    And by the way, f*** you.

    How’s that for scientific?

  14. By the way, Dennis:

    All the theories in the world added altogether would not make one fact.

  15. “Given your insults to me, you clearly lack juddgement and intellectual capacity. For these reasons I ask that you be barred from the Tusk.”

    It amazes me that you are too stupid to figure out that all you have to do is leave me out of the conversation.

    Dave Morrison et all are right. You should simply be ignored.

  16. “et al.” and who is that, Dennis?

    So far, Dennis, you’ve provided me with a copy of Morrison’s mail. Please do start a blog on me personally and share the rest of your correpondence concerning me.

    You’ll be famous, and they’ll be remembered by future historians as well.

    Once again, you have not demonstrated that even 1 of the features you see are geoblemes, little less that they are dated to the YD.

    Since lots of folks are headed to Meteor Crater, why don’t you join them and learn how its done.

    You have your own blog. What say you and Rich stay there until you can verify one of them?

    In the meantime, Ed Weiler needs to be fired.

  17. Given your insults to me, you clearly lack judgment and intellectual capacity. For these reasons I ask that you be barred from the Tusk.

    Yeah, right, I’m sure it must have taxed your own judgment, and intellectual capacity, to its maximum extent to digress off topic, and drag me into the conversation with “Tell Dennis to f*** himself”
    I was trying mind my own business, and stay off the Tusk when You dragged me off topic into this conversation with that small minded, and vulgar, insult. And with your well thought out, and uncalled for, choice of words, you set the level of acceptable insult/respect in any response to you. The gloves are off.
    In point of fact you have never proven your subjective interpretation of Indian oral traditions by identifying a single impact structure either. But there’s no surprise there. Relying on subjective interpretation of myth to understand the past didn’t work for Velikovsky either. Your approach is no different. You say the difference is that you use physics. Whose physics? You’re no physicist. You aren’t even any kind of scientist.
    Your vast sense of self importance is astounding. But where you see yourself as the dean of impact science, I see an old fool with delusions of grandeur. I don’t see the academic credentials to justify even reading your book. Much less any reason to treat you as the important scholar you imagine yourself to be.
    Personally, I’d rather just stay off the Tusk, and ignore you. But you make it impossible. You say you’d like to see me banned from posting on the Tusk for my disrespect to you. But you are too clearly too senile, or stupid, to connect the dots, and figure out the simple fact that if you want me to stay out of the conversation, and quit reminding folks that I am convinced you are a liar, a fraud, and a delusional old fool, you have to begin by leaving me out of it.

  18. Enjoyed the post, a very lengthy one with plenty to consider. It is always good to see a thrashing of ones fave theories be pointedly destroyed in print. This doesn’t mean the anti theory has the final say. I was dissappointed in the closing paragraph decalrative of not caring one way or the other.

    Was there an “extraterrestrial event” somewhere on or above North America at 12.9k years BP? I have no idea. Ultimately, I don’t care whether there was a 12.9k impact. I just want to know what was going on then. If there was, I see no reason to believe – at this point – that it had an impact on people, flora, fauna, or climate. We could be dealing with an extraterrestrial impact that had no terrestrial impact!

    Either the article or the statement are a herring.

    Also found the language and bitterness which composed half of the comments to be out of place. I know this is not a scientific journal of any standing, but really, if I want epithets and conspiracy I try godlikeproductions to get my fill of expletives and outlandish claims. Still I look forward to each post as they arrive and enjoy the idea of a time-distant apocalypse on this continent.

  19. VH:

    The dating of the Carolina Bays (thousands of elliptical depressions scattered along the Atlantic Coastal Plain) was also largely ignored or misstated (p. 127). One minute spent searching the internet turned up three GSA abstracts with OSL dates clearly showing that the sand rims around some Bays date to between 15,000 and 40,000 years BP and between 70,000 and 80,000 years BP. Some rims were active “during multiple phases over the past 100,000 years.”

    Do you have an explanation for the Carolina Bays yourself? Especially the alignments and the mechanism of their forming? The Impact Team had the right to put forth a scenario that includes a possible explanation of both points, and you have the right to disagree and turn it into a dialog. That takes openness on both sides. I myself appreciate that you’ve taken the time to write such a long critique.

    If the CBs are not from the time of the Y-D, no matter what caused them and when, the two questions still have no clear answer. Could it be another and different impact? Those how believe impacts come very rarely (in human time) will always be hard to convince that any impact was part of their provenance and might fight tooth and nail against it, pulling in any and all studies that have evidence against impacts. That is their right. The Impact Team tried to piece together disparate evidence into a full interdisciplinary gestalt. If they didn’t get it 100% right, or even 50% right, give them some credit for having the cojones to take a stab at it. Trying to piece together a possible new paradigm is not the easiest exercise in the world, and is fraught with a lot of ducking from pot shots and full bore cannon fire.

    Don’t forget that evolution and ice ages took decades for the dust to clear. It took decades to get rid of the ether. It took centuries to outgrow Aristotle, and those who participated lost more than a few night’s sleep from the attacks upon them by proponents and defenders of established ideas. And where would we be now if someone hadn’t convinced the scientific establishment that rocks, do, indeed, fall out of the sky? I do not expect us to know for a very long time the full story about rocks falling out of the sky. I expect there to be guesses that don’t pan out and seemingly contradictory evidence that is, nevertheless, true and at some point those will be fitted together. But that time is not now.

    Do you acknowledge any of their evidence at all as being valid, from your own single discipline POV? (And pardon if you have more than a single discipline; I don’t know your history. If so, perhaps you can still answer the question part of that question.)

    Do you acknowledge that they have gotten any of their interpretation correct?

    Like Ed Grondine, I have no “credentials,” as Dennis Cox is arguing about E.G., and therefore, according to Dennis my thinking is maybe of no importance. But I have a good mind and a curious one, and enjoy the puzzle of the Y-D, the mammoths, the beginning of the Holocene, and am open-minded about impacts and their frequency and their possible impact on the time of man, if any. Few geological features on Earth are as enigmatic as the Carolina Bays. I am not satisfied that an impact or secondary impacts created them, but I know enough about them to say that so far no one has explained them well enough. Since all other/earlier theories about them have serious shortcomings, I don’t pick on The Impact Team because theirs doesn’t fit all the evidence, either. And I am not aware of any more recent stabs at explaining them.

    So, if none of the explanations are correct, may I ask if you are also hammering on the earlier CB explanations? And if not, why not?

    In the meantime, I’ve gleaned much more facts about them since the 2007 conference, so I am happy that they tried. But science does demand that others challenge their interpretation and piecing together of the facts. It is always a work in progress. So, have at them, and may the best interpretation win.

  20. Dennis, Velikovsky was an E.P. wannabe.

    There was nothing subjective in my understanding of what was passed down, as there was an archaeological record to compare the accounts with. The physics I used was the standard physics of impacts, and normal astrophysics.
    All foot noted in the book you refuse to read.

    You have no understanding of the effort it takes to identify smaller ancient impacts, little less larger ones. What my work did was to limit the search space, and gather what evidence bore on that search.

    Your gloves have been off from the first time you appeared here and I told you that your “features” were not likely from the YDB, due to the human fatality rates. Note that Holliday and Kennett are currently forming estimates, and neither of them agrees with your “features”. I don’t either.

    From the first, in 1997, I dealt with Mars nuts who think that the nation has nothing better to spend money on than flying a few men to Mars for a few days. They were followed by the only asteroids hit bunch. They in turn were followed by the nu age folks. And now you come along, or send Rich…
    it has been said that a person is known by his enemies. Thanks for joining with so many other deluded halfwits.

    Pierson is very coherent and focused. You two are not.

    By the way, you can tell your friends that my important correspondence is not handled by any of the email accounts I use on my home computer.

    Aside from that Ed Weiler needs to be fired, and Morrison along with him.

    Steve, as I pointed out much earlier here there was Clovis activity around the Carolina Bays, and so they had to be pre-Clovis.

    It looks to me like the Perigee Zero folks have back tracked to an ice impact site. But that impact appears to have been tens of millenia before the YDB.

    In this regard I did much better than Firestone, Kennett, et al., as I avoided the Carolina Bays when writing about the YD event.

    Its too bad Benny shifted the Cambridge Conference to AGW scepticism, as I would have known of Firestone’s shift from supernova to supernova and impact.
    If that networking had of been operational, many of the problems that have arisen would have been handled early on.

    VH, if you want to expand your expertise from a regional level to a global level, then perhaps George will repost the Assiniboine accounts and I will demonstrate what a useful tool impact events are when dealing with discontinuities.

  21. “The problem isn’t with what your ancestors said, or my ancestors said.
    The problem is your confusion in understanding what they said and say.”

    so you are saying that no one but you can really interpret what your and mine ancestors have said? and of course you are alone all knowing and know every word my ancestors have said?
    now you are trying to get people to believe what you don’t even believe is true, unless and until you alone in all the world can fart and twist and screw the stories over real good to make them palatable your ignorant [email protected]@ friends and believers?

    thank you for admitting it to everyone. because that sir is exact what I accused you of at the start of this stupid little game you are playing. and why I keep asking you to shut the hell up because you don’t know what you are talking about much less do you actually believe what you are trying to peddle off as
    “native myths” .

  22. This will be my last post on Cosmic Tusk, you are free of my amateur musings.
    I am sure that George is greatful for those of you who defacate all over his site and drive away readers. Now you have it for your out private outhouse. The interest was already thin due to more pressing current problems.
    You remind me of children clamouring for attention and resorting to violence if you don’t get it.

    Farwell to Steve, the other ‘dilletant’, thanks for all. My solution to the NE folds at CB was: Suppose a left hand spin on a flat projectile with a high angle of incidence (45-60 degrees) This might produce the effect??

    Thanks for your effort in providing the forum George.

  23. CL –

    You are the one adding the nu age “Allegewi” stuff to the traditions.

    I don’t talk about “”native myths”, I pass on historical traditions.

    You have wasted a lot of my time, and the time of those here, with your confusion.

    You have not given us your true name, but hide while you commit pokvano.

  24. Hello Ed Grondine,

    Dennis Cox doesn’t tell me to do anything — I’m a totally independent operator who has studied his posts, sites, and book very carefully, while rather easily finding plenty of confirming evidence everywhere I look within a 160 km radius from Santa Fe, NM, as well as Google Earth and Maps and NASA Worldwind views around the world. So, I encourage others to enjoy making the same kind of confirming discoveries.

    I respected your book too, and always read your posts with appreciation.

    It may be that comet fragment showers that produce geoablation and glazed, fractured surface rocks may occur frequently in the last million or so years.

    It occurred to me that if you don’t have high speed broadband access, then most of the evidence that Cox offers won’t be available for your enjoyment.

    In mutual service, Rich

  25. Hi Rich –

    Here we are discussing Dennis Cox again.

    Given the weathering rates in the western US, and the survival times of features, Dennis has not shown that any of them are geoblemes. Nor has he shown any dates for any of them. Thus he has not shown that they come from any comet shower, little less a shower at the YD. They could simply have accumulated over time, that is if they are geoblemes.

    As Dennis has a site to publicize his “observations”, may I suggest to both you and him that you keep your insights there until his “observations” are confirmed as geoblemes and dated?

    Perhaps you can find someone to help you with this at the Meteor Crater field school.

    As I have mentioned before, as Boslough’s model requires impactors moving at cometary speeds, not asteroidal speeds, I wish you luck in your quest.

  26. Yeah, doesn’t it just burn your hide when you aren’t treated like the supreme dean of impact science? I’m not sure I get this double standard of yours Ed.
    In point of fact, you have never proven your much touted ability to use Indian lore to identify the location of an impact event either. No surprises there though. Velikovsky tried to get a clear picture of the past using myth, and legend.  The materials he used were written texts going back to the bronze age. And he got his ‘Worlds in Collision’ hypothesis from them. That book was a failed hypothesis. But it was convincing enough in it’s day that Albert Einstein was reading it on his death bed.
    You claim that Indian oral traditions contain clear, and lucid, memories of impact events going back 13,000 years. But no one has ever demonstrated that a confident picture of the past can be re-constructed using 5,000 year old memories that were written down. Much less that it can be done using oral traditions more than twice as old.
    You claim that the difference in your approach, and Velikovsky’s, is that you use physics. But you fail to present any academic credentials to demonstrate that you have any comprehension at all of the physics you say you use. Much less any right to a negative opinion of the work, or persons, who do. Nor have you cited a recognized impact physicist who can corroborate your claims.
    You are extremely sensitive to demands for peer reviewed references. And any demand to verify your claims gets attacked with stuff like:

    “Dennis, I think you’re leaving out of your list of contacts some people from Arizona, Morrison’s allies. The immediate PNAS link and your demand for references from refereed literature are their usual tactic.”

    Apparently we are supposed to just take your word for it.
    There’s two sides to everything. I actually do have the scientists you’ve been going on about on my mailing list. And without exception, all of the mainstream planetary scientists you are so critical of, and that I have been corresponding with, have an even lower opinion of you, then you do of them. And they have the academic credentials to back it up.
    My favorite was Dave Morrison’s (Senior scientist, NASA Ames Research center)  reply:

    “I do my best to ignore Grondine. He is not reliable. For more than a decade he has consistently written that I favor the Nemesis hypotheses, and he sticks to this unfounded belief no matter how many times I correct him. He used to show up at scientific meetings to ask weird questions, but he doesn’t seem to travel any more. As you note, however, his rejections by scientists have no effect on his vast self-confidence.
    I have no idea who he refers to as “some people from Arizona”.  He has had run-Ins with my colleagues from California, Colorado, and New Mexico more than Arizona. But it doesn’t matter, as we all now ignore him.”
    David Morrison

    Since you say you understand impact physics so well, whose test did you pass? You darn sure didn’t take any course they were offering.
    Bottom line: You have never used Indian oral traditions to identify the location of a single potential impact structure for field work. And you have never proven that oral traditions contain verifiable 13,000 year old memories.
    However, for those interested in going crater hunting, North America really did get hit very hard by major, multiple fragment, impact storms in the geologically recent past, probably more than once. And the planetary scarring of those events is only a few thousand years old. There’s a few hundred new craters listed on my blog. In surfaces that date to the late Pleistocene. And they are crying for field work.
    While your approach is to tear down the mainstream scientists who disagree with you. Or who are not supportive of your claims, I prefer to work with them.
    And since this is not an open forum. But is in fact, the world according to Ed. And all opposing views, including those of many of the top mainstream planetary scientists on this side of the world, are invalidated, arguments with you are pointless.
    You’re gonna love this Ed. You can have your own private playground to say anything you want here. Because this really is my last post on the Tusk.
    In the future I will be following the advice of many of my friends, and advisors. And I will be following the lead of my friend, Dave Morrison, by simply ignoring you.

  27. Great.

    Goodbye, Dennis.

    When you’ve demonstrated that any of the features you see are geolblemes, and have at least some kind of rough date for them, then we’ll be happy to hear from you.

    But I don’t think you’ll get much help from Morrison in your quest, as for Boslough’s model to work the impactor has to be friable and moving at a very high velocity.

    In other words a comet fragment.

    You need to remember that just because someone will write to you does not mean that they endorse your conclusions.

    As far as who I am in contact with, whether within the impact community, the archaeological community, the Native American community, the geological community, NASA, or the nuclear community,

    The less you and Morrison know, the better.

    When you first showed up here, I told you to look at scaling laws.
    You still haven’t done that.

    As far as resources for geobleme searches go, others here at the Tusk have a far higher claim on them than you. Again, the less you and Morrison know about their current efforts the better.

    Quite frankly, it really pisses me off when you compare my work with Velikovsky’s without ever having read any of my work.

    George, now that Dennis is going, would you repost the Assiniboine (Nakota) impact account fragments, so I can walk Holliday through the process without being disturbed?

  28. For the record of lakes which drained around 12.9kybp, Ancient Lake Siota, in eastern Pennsylvania( Near Wind Gap, Pa), was a rather large inpoundment(1-3km high ice dam) which breached..12.9kybp( as radio-carbon dated by debris from the outwash bars).

    This breach changed the entire drainage pattern in the Broadheads Creek Valley such that instead of flowing into the Delaware vic Delaware Water Gap,PA it now feeds into the Lehigh River near Palmerton ,Pa. This was/is covered in an obscure 60’s publication titled Geological Field Trips of Eastern Pennsylvania (or words to that effect). The area is populated by many moraines, kames and eratics– generally along the line of Interstate 80.

    The terminal moraine for Lake Siota is crossed by State Route 33 vic Cherry Valley. Just north of that crossing to the east, lies perched atop a quarry, a large pile of glacial cobbles. This is but a small but powerful insight as to the size of the natural dam that stretched across the valley.

    I have found sub-surface chalk specimens in the large well sorted sand pits near there. Yet there are no chalk deposits anywhere along the projected flow of the lobe of the ice sheet.

  29. Anybody who is overly fixated on credibility/credentials over syllogistic empiricism is exhibiting acute parataxis, perhaps because they stand to lose something valuable (i.e. grant moniez).

    I want to point out that impact craters are complicated critters in the sense that it only takes a single instant to jumble up and reorginize millions of years of strata. As a consequence of elastic rebound there will be a central uplift which ejects its debris into the rim. Firestone/West et al (2006) said that radiocarbon dates tend to be of underlaying formations, a point which even Holliday (1996) might agree with. You might obtain wildly varying dates from a single crater. As the Firestone group successfully depicted many times, all of these elliptical craters have mutually aligned axes, with a spatter or star-fire pattern all pointing towards a single Prime.

    Impact forensics is interesting stuff! We appreciate the skeptics, because books are written for one of two reasons: to illustrate a subject that we have a great mastery over or to masterfully advance a well-thought out theory for public vetting in order to make it even better. Gristle from grist, we get the gist: the Quaternary ended abruptly, in a single day. All else is the juicy equivocation. What a time to be alive!

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