From the University of South Carolina – PNAS: Topper site in middle of comet controversy
By Peggy Binette, USC
Did a massive comet explode over Canada 12,900 years ago, wiping out both beast and man in North America and propelling the earth back into an ice age?
That’s a question that has been hotly debated by scientists since 2007, with the University of South Carolina’s Topper archaeological site right in the middle of the comet impact controversy. However, a new study published today (Sept.17) in the Proceedings of the National Academy of Sciences (PNAS) provides further evidence that it may not be such a far-fetched notion.
Albert Goodyear, an archaeologist in USC’s College of Arts and Sciences, is a co-author on the study that upholds a 2007 PNAS study by Richard Firestone, a staff scientist at the Department of Energy’s Lawrence Berkeley National Laboratory.
Firestone found concentrations of spherules (micro-sized balls) of metals and nano-sized diamonds in a layer of sediment dating 12,900 years ago at 10 of 12 archaeological sites that his team examined. The mix of particles is thought to be the result of an extraterrestrial object, such as a comet or meteorite, exploding in the earth’s atmosphere. Among the sites examined was USC’s Topper, one of the most pristine U.S. sites for research on Clovis, one of the earliest ancient peoples.
“This independent study is yet another example of how the Topper site with its various interdisciplinary studies has connected ancient human archaeology with significant studies of the Pleistocene,” said Goodyear, who began excavating Clovis artifacts in 1984 at the Topper site in Allendale, S.C. “It’s both exciting and gratifying.”
Younger-Dryas is what scientists refer to as the period of extreme cooling that began around 12,900 years ago and lasted 1,300 years. While that brief ice age has been well-documented – occurring during a period of progressive solar warming after the last ice age – the reasons for it have long remained unclear. The extreme rapid cooling that took place can be likened to the 2004 sci-fi blockbuster movie “The Day After Tomorrow.”
Firestone’s team presented a provocative theory: that a major impact event – perhaps a comet – was the catalyst. His copious sampling and detailed analysis of sediments at a layer in the earth dated to 12,900 years ago, also called the Younger-Dryas Boundary (YDB), provided evidence of micro-particles, such as iron, silica, iridium and nano-diamonds. The particles are believed to be consistent with a massive impact that could have killed off the Clovis people and the large North American animals of the day. Thirty-six species, including the mastodon, mammoth and saber-toothed tiger, went extinct.
The scientific community is rarely quick to accept new theories. Firestone’s theory and support for it dominated the annual meeting of the American Geophysical Union and other gatherings of Paleoindian archaeologists in 2007 and 2008.
However, a 2009 study led by University of Wyoming researcher Todd Surovell failed to replicate Firestone’s findings at seven Clovis sites, slowing interest and research progress to a glacial pace. This new PNAS study refutes Surovell’s findings with its lack of reported evidence.
“Surovell’s work was in vain because he didn’t replicate the protocol. We missed it too at first. It seems easy, but unless you follow the protocol rigorously, you will fail to detect these spherules. There are so many factors that can disrupt the process. Where Surovell found no spherules, we found hundreds to thousands,” said Malcolm LeCompte, a research associate professor at Elizabeth City State University and lead author of the newly released PNAS article.
LeCompte began his independent study in 2008 using and further refining Firestone’s sampling and sorting methods at two sites common to the three studies: Blackwater Draw in New Mexico and Topper. He also took samples at Paw Paw Cove in Maryland, a site common to Surovell’s study.
At each site he found the same microscopic spherules, which are the diameter of a human hair and distinct in appearance. He describes their look as tiny black ball bearings with a marred surface pattern that resulted from being crystalized in a molten state and then rapidly cooled. His investigation also confirmed that the spherules were not of cosmic origin but were formed from earth materials due to an extreme impact.
LeCompte said it was Topper and Goodyear’s collaboration, however, that yielded the most exciting results.
“What we had at Topper and nowhere else were pieces of manufacturing debris from stone tool making by the Clovis people. Topper was an active and ancient quarry at the time,” LeCompte said. “Al Goodyear was instrumental in our approach to getting samples at Topper.”
Goodyear showed LeCompte where the Clovis level was in order to accurately guide his sampling of sediments for the Younger Dryas Boundary layer. He advised him to sample around Clovis artifacts and then to carefully lift them to test the sediment directly underneath.
“If debris was raining down from the atmosphere, the artifacts should have acted as a shield preventing spherules from accumulating in the layer underneath. It turns out it really worked!” Goodyear said. “There were up to 30 times more spherules at and just above the Clovis surface than beneath the artifacts.”
LeCompte said the finding is “critical and what makes the paper and study so exciting. The other sites didn’t have artifacts because they weren’t tool-making quarries like Topper.”
While the comet hypothesis and its possible impact on Clovis people isn’t resolved, Goodyear said this independent study clarifies why the Surovell team couldn’t replicate the Firestone findings and lends greater credibility to the claim that a major impact event happened at the Younger Dryas Boundary 12,900 years ago.
“The so-called extra-terrestrial impact hypothesis adds to the mystery of what happened at the YDB with its sudden and unexplained reversion to an ice age climate, the rapid and seemingly simultaneous loss of many Pleistocene animals, such as mammoths and mastodons, as well as the demise of what archaeologists call the Clovis culture,” Goodyear said. “There’s always more to learn about the past, and Topper continues to function as a portal to these fascinating mysteries.”
Goodyear joined USC’s College of Arts and Sciences and its South Carolina Institute for Archaeology and Anthropology in 1974 to pursue prehistoric archaeology.
The Topper story
Albert Goodyear, who conducts research through the University of South Carolina’s S.C. Institute of Anthropology and Archaeology, began excavating Clovis artifacts along the Savannah River in Allendale County in 1984. It quickly became one of the most documented and well-known Clovis sites in the United States. In 1998, with the hope of finding evidence of a pre-Clovis culture earlier than the accepted 13,100 years, Goodyear began focused excavations on a site called Topper, located on the property of the Clariant Corp.
His efforts paid off. Goodyear unearthed small tools such as scrapers and blades made of the local chert that he believed to be tools of an ice age culture back some 16,000 years or more. His findings, as well as similar ones yielded at other pre-Clovis sites in North America, sparked great change and debate in the scientific community.
Goodyear reasoned that if Clovis and later peoples used the chert quarry along the Savannah River, the quarry could have been used by even earlier cultures.
Acting on a hunch in 2004, Goodyear dug even deeper into the Pleistocene terrace and found more artifacts of a pre-Clovis type buried in a layer of sediment stained with charcoal deposits. Radiocarbon dates of the burnt plant remains yielded ages of 50,000 years, which suggested man was in South Carolina long before the last ice age.
Goodyear’s findings not only captured international media attention, but it has put the archaeology field in flux, opening scientific minds to the possibility of an even earlier pre-Clovis occupation of the Americas.
Since 2004, Goodyear has continued his Clovis and pre-Clovis excavations at Topper. With support of Clariant Corp. and SCANA, plus numerous individual donors, an expansive shelter and viewing deck now sit above the dig site to allow Goodyear and his team of graduate students and public volunteers to dig free from the heat and rain and to protect what may be the most significant early-man dig in America.
The Topper timeline
1998 Goodyear and his team dig to a meter below the Clovis level and encounter unusual stone tools up to 2 meters below the surface.
1999 Team of outside geologists visit Topper site and propose a thorough geological study of the location.
2000 Geological study done is by consultants; ice age sediment is confirmed for pre-Clovis artifacts.
2001 Geologists revisit Topper and obtain ancient plant remains deep in the Pleistocene terrace. Optically stimulated luminescence (OSL) dates sediment above ice-age strata show pre-Clovis is at least older than 14,000 years.
2002 Geologists find new profile showing ancient sediment lying between Clovis and pre-Clovis, confirming the age of ice age sediment layer between 16,000 – 20,000 years.
2003 Archaeologists continue to excavate pre-Clovis artifacts above the Pleistocene terrace. New and significant Clovis artifacts are found.
2004 Goodyear discovers major Clovis occupation on the hillside. Additionally, radiocarbon dates for sediment associated with pre-Clovis artifacts come back at 50,000 years.
2005 “Clovis in the Southeast” conference held in Columbia, S.C., with tours of Topper and Big Pine Tree sites.
2006 The 3,500-square-foot roofed structure is built over pre-Clovis excavations.
2007 Firestone study about a possible Clovis comet is published in the Proceedings of the National Academy of Sciences, including evidence from Clovis age sediments from Topper.
2008 PBS “Time Team America” spends a week at Topper filming for an hour-long television special devoted to Topper.
2008 SCETV broadcast of “Finding Clovis,” a public television presentation of Topper Clovis. 2009 PBS “Time Team America” program airs.
2011 Topper and Big Pine Tree included in a study of post-Clovis Paleoindian decline/reorganization that is published in the journal “Quaternary International.”
2011 The first permanent exhibit of Topper artifacts installed at the University of South Carolina Salkehatchie.
2012 Independent study of micro-spherules related to an extra-terrestrial impact hypothesis is published in the Proceedings of the National Academy of Sciences using Clovis-age sediments from Topper that confirm the original 2007 Firestone study.
2013 The pre-Clovis occupation of Topper will be presented in October at the international conference on the peopling of the Americas, titled “Paleoamerican Odyssey,” in Santa Fe, N.M. http://www.paleoamericanodyssey.com/
=====================================
h/t to Dennis Wingo
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Great article. The whole pre-Clovis ‘heresy’ debate fractured American science deeply through the end of the 21st century. Glad to see a paper that addressed why the initial findings weren’t easily replicated. Good science articles like this make WUWT a greg must read site.
Interesting. Everybody should read The First American by Hardaker. http://www.amazon.com/The-First-American-Suppressed-Discovered/dp/1564149420 It caused a big controversy back in the old days due to dating (250,000 years!). I wonder if they’re going to start looking into that now. Even 50,000 years old was very tough for people to accept back then too. It took 30,40 years to get to 50,000 years old. Talk about slow progress!
Maybe OT, but “The scientific community is rarely quick to accept new theories”.
Didn’t take the warmists long, though.
This will be of interest to people investigating the younger Dryas
http://tallbloke.wordpress.com/2011/06/24/comet-storm-a-hypothesis-explaining-megafauna-extinction-and-the-younger-dryas/
oldseadog says:
Didn’t take the warmists long, though.
Acceptance is way easier when your check depends on it.
The presence of the black spherules of terrestrial origin means a major ground impact. OK. I presume that based on a search for Iridium concentrations in various N American sites of the right age, it may be possible to locate the impact site. I understand that is how the Yucatan impact site 65m years ago was located.
Perhaps it was in Hudson Bay which is quite shallow. Being so recent it would otherwise have left a very rather obvious mark.
Is there any evidence for a simultaneous change in the sea level around the 40-50 degrees latitude mark? That would indicate that the Earth wobbled and settled on a slightly altered axis. If this is the case then it would change the ‘expectable’ future of climate, in effect putting us forward or back on the Milankovich Cycle. High latitude, high speed impacts are quite capable of altering the length of the day and the tilt of the earth and the precession rate. It sounds as if this may have been one. Perhaps we have broken out of our 500k year pattern. Interesting.
Goodyear & Firestone , hmm .
Yet another reason to provide the most detailed account possible of one’s experiment.
@Nerd
Excellent link.
“‘…the dates were so old that to take them seriously would impugn their own scientific credibility.”
So it is not for the first time that people discovering scientific truths turn silent in order to protect their positions from those contollling the dominant paradigm.
The difference with ‘climate science’ is that the evidence for a CO2 hypothesis never dominated anything – it was just a hypothesis. At least the Clivis First supporters had plenty of evidence, they just rejected other evidence.
Surely is it interesting to note that the Reis Map of Antarctica (the original was painted on animal skin) shows what the shoreline was about 250,000 years ago, a similar age? Here we go again…
Hmmmm…I notice a complete lack of references to “peer review” and lots of work trying to independently replicate the earlier study / studies.
Who would have thought of that…..real science in this field, unlike certain others (cough…AGW / warmists…..cough). Could it be that these folks actually understand the scientific method while our warmist friends don’t?
vukcevic says:
September 20, 2012 at 10:50 am
>> Goodyear & Firestone , hmm .
Yes, you have to wonder is someone is having a laugh sometimes. Why is no one mentioning Dr Dunlop’s noteworthy research on this period 😉
“The so-called extra-terrestrial impact hypothesis adds to the mystery of what happened at the YDB with its sudden and unexplained reversion to an ice age climate,… ” Goodyear said/
So is it now common practice to misuse the term “ice age” instead of glacial period ? Or are these guys archeologists who do not understand the terms they are using?
I presume these “black spherules” have also been found at non-quarry sites, else they would only some kind of soot related to tool manufacture.
Crispin in Waterloo says:
September 20, 2012 at 10:49 am
Perhaps it was in Hudson Bay
Nastapoka (http://en.wikipedia.org/wiki/Nastapoka_arc) was most likely hit by a huge lamp of iron which is slowly sinking into the upper mantle, as both the Geoid depression and the strong magnetic field intensity indicate.
http://www.vukcevic.talktalk.net/Hudson.gif
Crispin:
Would a comet have much iridium?
NZ Willy:
Just how much soot does chipping chert produce?
Is there any evidence for a simultaneous change in the sea level around the 40-50 degrees latitude mark? That would indicate that the Earth wobbled and settled on a slightly altered axis. If this is the case then it would change the ‘expectable’ future of climate, in effect putting us forward or back on the Milankovich Cycle. High latitude, high speed impacts are quite capable of altering the length of the day and the tilt of the earth and the precession rate. It sounds as if this may have been one. Perhaps we have broken out of our 500k year pattern. Interesting.
kg. The mass of a kilometer radius comet is ballpark 
kg. The ratio of the masses is thus ballpark of 
(comet to planet). Even comet with a diameter of 4 kilometers would still have only one ten billionth the mass of the Earth, and would have a one part in a billion impact on any macroscopic aspect of the Earth’s orbit or rotation rate or inclination. I’m not seeing that having much impact on length of day or precession rate or any Milankovitch cycle behavior — I doubt that one could detect its influence compared to other natural sources of “noise” (nutation, tidal coupling, orbital resonance with the gas giants, movement of the continents, continental-scale uplift and downfall, melting of icepacks (which alters the moment of inertia tensor, not just its magnitude. A largish comet would have roughly the same sort of effect on tensor moments than the eruption/explosion of Tambora, which caused 16 cubic miles of mountain to basically blow away into the atmosphere, and there are literally dozens of Tambora-scale events likely to have occurred over the last 12,000 years.
Crispin, “altering” is difficult to argue with, but “measurably” or “significantly” altering requires some defense, does it not? The mass of the Earth is ballpark
Even if the comet was considerably larger — say, 5 km in radius (and hence 125 times more massive) it would barely perturb the Earth’s orbital properties. The Earth is small compared to stars and gas giants, but it is enormous compared to most observed comets or probable candidate asteroid sizes.
I may be making some sort of arithmetic or conceptual error here, so please feel free to correct me — this is back of the envelope stuff — but I’m having a hard time agreeing with you that alteration of axial tilt or length of day or eccentricity of orbit due to any likely comet impact at any latitude would have any serious effect on the climate beyond the obvious, and extreme, short-and-medium term effects of releasing a few gigaton-of-TNT-equivalents of energy, cubic miles of vaporized or pulverized matter, and a supersonic shock wave of pyroclastic flow sufficient to blow down and/or ignite or bury or flood any structure within a million square kilometers or so of land surface area. Which might well be enough, but which isn’t orbital.
Having meditated upon Tambora (and Krakatoa) and its (their) apparent LACK of clearly visible long term impact on the climate, I’m increasingly inclined towards the belief that the Earth’s negative feedback is more than sufficient to cope with even gigaton-scale explosions involving cubic miles of ejecta. There is a “suspected” impact site for a crater large enough to dwarf Krakatoa or Tambora in Hudson Bay, although AFAIK there is no hard evidence that proves it to be such a site or (obviously) a site that has the right age to have been associated with the YD.
I’ve read a number of articles suggesting a meteoric cause for the YD, and there is “some” evidence that supports it. So far, though, I don’t think there is smoking-gun-specific evidence that e.g. includes the probable impact site or any sort of hint about how large it was. It might not have had to be very large, of course, if the Earth was still in the critical regime in between warm and cold phase where small fluctuations would have been nonlinearly amplified by the critical instability, or if it (for example) broke an ice dam and caused the OTHER major suggested YD cause, sudden freshwater dilution of the North Atlantic that interrupted the thermohaline circulation for a thousand years or so.
rgb
vukcevic says:
September 20, 2012 at 11:28 am
“was most likely hit by a huge lamp of iron ”
Was there a genie in the lamp?
rgbatduke says:
September 20, 2012 at 11:55 am
Is it possible that since the Younger Dryas impact occured at a time of climate transition, that the climate could have been more sensitive to pertubations?
The other events that you mention all occurred when the climate was solidly within the inter-glacial.
Strange coincidence: BBC4 (UK) is at this moment transmitting ‘Horizon’ about the asteroids, there are apparently 900 of 1 km or larger diameter.
So how does this timeline work?
16,000 years ago there was an ice age culture in NA. It started to warm up. Until that ignorant ball of rock about 13,000 years ago, cooled things off a bunch. When the dust from that settled, it started to warm up. Something happened about 600 years ago, cooled things off a bunch, we call is the LIA. When the dust from that settled, it started to warm up. Again.
I conclude from the available evidence that the internal combustion engine was invented 16,000 years ago. There’s no way that the earth could have been warming for 16,000 years punctuated only by the YD and the LIA from just natural causes could it?
Oh wait. This was a North America thing, not a global thing. Probably only “regional”. Never Mind.
@rgbatduke first
There is an important assumption you make in your reasonable back of the envelope analysis that must be dropped: that when it comes to changing the pole or rotation, the Earth is basically lke a solid ball, cricket ball if you will. It is not.
There are three poles for the Earth, the lithosphere, the core, and everything in between. They rotate slightly differently and the lithosphere can be perturbed independently of the other two. They are not, at present, aligned. They were disturbed 3200 years ago and probably again in about 1650 BC. The flooding of the Dogger Bank was probably a single-day event. Ditto the civilisation that farmed what is now the floor of the Irish Sea. There are stove walls around fields in Wales that go into the sea and continue across the seafloor. This is describe in detail in a book: Atlantis of the west: the case for Britain’s drowned megalithic civilization”, by Paul Dunbavin, 2003. The first three chapters are relevant to the axes and their relative motion. He postulates there was a 7 year long cylical wobble that was significant enough to be visible to humans. It has now damped down considerably but is still detectable (to about 10 inches I think).
Basically a high latitude impact or as described in http://cometstorm.wordpress.com/2011/04/27/a-different-kind-of-climate-catastrophe-2/ ( h/t Tallbloke) can make the lithosphere wobble without immediately affecting the major % of the mass of the Earth. It is one reason why the theory that enough ice piling up on the poles, asymetrically, can make the ‘earth flip’ (in fact, move the lithosphere relative to the mantle). My reference to the Milankovich Cycle was really made while thinking about the precession of the tilt. To be clearer, I was thinking of the change in insolation between summer and winter which goes through a cycle. I was not thinking about moving the Earth from its orbital path, just that the effect is the same.
@vic
That iron is consistent with most of the theory in the link above, but only if it is really recent.
@MarkW
Iridium is very rare on Earth and much more plentiful in asteroids and rocky comets. It is used as one of the proofs that some lump is extra-terrestrial. When blasted all over the show, a layer of iridium indicates an inmpact, the thicker the layer, the closer it is assumed to be. That is how the Yucatan impact site was located, first generally then confirmed from the air.
A definite impact site is the crater around Sudbury Ontario, but it is old. They are mining the nickel from the bolide and it used to provide 95% of the nickel in the world. Most of the world’s nickel is in the core out of reach. 🙂
So, a comet’s impact set off an ice age that lasted a 1300 years; and all of this took place over 12K years ago.
So, what caused this ice age to end and warming to begin?
Let’s see, oh, it must have been elevated levels of CO2, because THE DEBATE IS OVER – CO2 CAUSES GLOBAL WARMING. THERE IS A SCIENTIFIC CONSENSUS ON THIS FACT.
What you say, CO2 levels were not elevated at the time the YD ice age ended and the climate warmed up.?
Well then , if you believe that you are fascist/commi pig s**t on the payroll of big oil.
So why a comet ? Is the core of a comet not simply a meteorite ? Presumably the ice coating would leave not a trace; the old tired worn out who dunit ice dagger murder mystery.
Re Mark W: “Is it possible that since the Younger Dryas impact occured at a time of climate transition, that the climate could have been more sensitive to perturbations?”
Good question. Problem is that nobody knows (to my knowledge) what the sensitivity is and what drives the move to and from glaciation. The thing that makes the YD so interesting is that it marked a strong move back to glaciation for a millennium after the climate was coming out of the last ice age. After the YD, the warming trend resumed, so you have 4 different moves in the direction of climate within the period of a couple thousand of years – a strong move toward warming starting around 15k years ago, a sudden and sharp cooling trend around 12,900 years ago, steady state during the cold, followed by a resumption of the warming trend 10,500 years ago. How do you explain any or all of these? The suggestion of an impact event answers the middle two.
And the YD event is thought by some to be a series of multiple impacts / airbursts centered about two sites in North America – Michigan and central Mexico. Think of thousands of Tunguska sized airbursts over the course of an hour as the earth rotates underneath a thick part of a incoming debris stream. Think continental extinction event. And there may be another center of impact. It is all very new and the discussion is very loud. The significance of this paper is that one set of critics have been shown to be wrong. Cheers –
http://www.whoi.edu/science/GG/paleoseminar/pdf/broecker88.pdf
One thing you need to know about such studies in areas like paleontology and such ancient studies of man, critters, and such is that the evidence is often fragmentary in the extreme, small fragments of bone and the like, similar to here. The evidence is so fragmentary that it is subject to a huge range of interpretations. Once someone digs up some such, they often spend decades arguing about what it actually means. This often runs into entrenched (to an extreme degree) interests which fight to keep their previously “established” theories intact to preserve their own prestige and standings in the academic community. An example was where some guy suggested that dinosaurs were warm blooded. He was attacked and basically saw his career take a big hit, and now, 20 years later, pretty much everyone agrees that dinosaurs were warm blooded. http://en.wikipedia.org/wiki/The_Dinosaur_Heresies .
I would not be surprised to see this new study, as well as any evidence for mankind in the Americas before about 13,000 years ago treated pretty much like a Watt on PBS interview.