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

American Airburst: Comet fragments destroy ancient Midwest culture

4th century AD impact would kill tens of millions today

The Washington Post
Smithsonian Magazine
University of Cincinnati press release

Comet Research Group member Ken Tankersley and his University of Cincinnati team published an astonishing paper this week in Nature’s Science Reports providing hard data suggesting that the Native American “Hopewell Culture” witnessed and suffered terribly from a cosmic onslaught just 1700 years ago.

The Cosmic Tusk is closely associated with the Younger Dryas Impact event 12,800 years ago. But regular readers know that this blog’s mandate is larger and includes all “comets and asteroids during human history,” as it says up topMany impacts and airbursts have occurred throughout the human experience, before and since the YDI, right up until modern times.

But impact deniers persist in their belief that NASA’s (flawed) impact frequency estimate are the final word, and that no one need go poking around for archaeological evidence of impacts during the human experience. Thank goodness for intrepid researchers like Tankersley and his team.

Look and ye shall find!

Did an exploding comet help end an ancient Native American culture?
The Washington Post
Feb. 4th, 2022

The earth was scorched and covered with ash. Buildings vanished, leaving nothing but charred marks in the soil where posts had been. Temperatures on the ground may have reached 1,400 degrees Fahrenheit.

Native Americans told of the sun falling from the sky and described a great horned serpent that dropped rocks from the heavens.

And after the event about 1,700 years ago, on a spot in what is now southwestern Ohio, scientists believe the Indians created a huge earthwork image of what they had seen: a streaking comet.

This week, experts at the University of Cincinnati said the explosion in the atmosphere of a piece of that comet — an “air burst” — could have led to the unexplained decline of the Hopewell culture, which flourished in the eastern United States from about 100 B.C. to about 400 A.D.

Their research was published Tuesday in the journal Scientific Reports.

The team, headed by anthropologist Kenneth Tankersley, described evidence of what must have been devastation among the extensive native communities of the Ohio River Valley, chiefly in southern Ohio.

But Tankersley said in an interview that the researchers could not determine how many people may have been killed.

“Without a time machine, we can’t say for certain,” he said Tuesday. “But everywhere we excavated … we found burned earth, fire hardened.”

He added, “We also found burned villages.”

At one site, he and his colleagues discovered “ash-covered surfaces with post-molds filled with wood charcoal,” they wrote.

At another site, the earth looked as if it had been exposed to heat from a blast furnace, and limestone “had been thermally reduced to lime,” a process requiring a temperature of about 1,400 degrees Fahrenheit, they reported.

“The Ottawa talk about it as a day when the sun fell from the sky,” Tankersley said, referring to a tribe from the northeastern United States and southeastern Canada. “It would have been that bright. If the air burst occurred during the daytime, it would have been as bright as the sun.”

If a similar event took place over New York or Washington, D.C., today, he said, “it would be mistaken as a thermonuclear device having gone off.”

The “air burst” happened roughly between 252 and 383 A.D., more than 1,000 years before major European contact with the Western Hemisphere.

“It’s not the idea that the air burst killed everybody,” Tankersley said. “But rather that it was a catastrophic event” that caused the socioeconomic breakdown of the culture.

Tankersley said the blast was probably similar to the explosion over the Tunguska River in Siberia in 1908, which flattened forests for hundreds of miles.

The Iroquois speak of a Sky Panther, Dajoji, which has the power to tear down forests. “That’s what happened in Tunguska,” he said. “It’s the exact same thing.”

The Hopewell are the genetic ancestors of the Iroquois, the Miami, the Lenape, the Shawnee and the Ojibway, said Tankersley, who is a member of the Piqua tribe of Alabama.

A drawing of the comet-shaped Milford earthwork based on E.G. Squier and E.H. Davis’s 1848 “Ancient Monuments of the Mississippi Valley.”

They built “monumental landscape architecture,” the authors of the study wrote, including the largest geometric earthen enclosures in the world, water management systems and massive burial mounds.

They also had a social network that reached from the Atlantic Ocean to the Rocky Mountains, and from Canada to the Gulf of Mexico, the authors wrote.

The name Hopewell comes from Mordecai C. Hopewell, who in the 1890s owned land where a massive earthwork complex that included 29 burial mounds had been found outside Chillicothe, Ohio, according to the National Park Service.

“The true tribal names of these people were lost over the millennia,” the Park Service says on a webpage about the Hopewell.

Tankersley said the Hopewell archaeological sites contained diverse material that probably came from the jumbled makeup of a comet, which is like a big, dirty snowball that picks up debris on its travels.

One day during the third or fourth century, based on radiocarbon dating, a chunk of a passing comet was broken off by Earth’s gravitational pull, he said.

It plunged into the atmosphere, where its frozen gases exploded and showered debris on the planet’s surface.

The suspected comet could have been any one of 69 believed to have passed close to Earth during that period, including Halley’s comet, which visited in April 295 and in February 374, Tankersley said.

He said excavation and research showed that the mysterious comet-like earthwork in Milford, Ohio, was built after the explosion because suspected comet remnants were found below the level of the earthwork.

The site is now beneath a local cemetery and has mostly disappeared, Tankersley said. But the earthwork had a flaring tail a half-mile long and a head more than a quarter-mile around, according to a U.S. Army Corps of Engineers map drawn in 1823.

It was also illustrated in a book published in 1848 by the Smithsonian Institution called “Ancient Monuments of the Mississippi Valley.”

“This is a great example of Native Americans documenting their own history,” Tankersley said — the Hopewell record of the disaster that may have ended its culture.

19 Responses

  1. From the Tankersley et al Nature Science Reports paper : ” Our interdisciplinary research focused on five comet airburst -related proxies including meteorites , Fe and Si rich microspherules , positive Ir and Pt anomalies and burned carbon rich habitation surfaces on Hopewell archaeological sites in the Ohio River valley …………………Twenty eight [ presumably calibrated ] radiocarbon ages place the Hopewell airburst proxies at 1699 -1567 BP [ 252-383 CE ]

    The Hopewell cataclysm must have left drifting residual evidence in Arctic ice cores and if we examine the NEEM records , 342 CE stands out as the most exceptional megafire year of the past two millennia exhibiting the highest concentrations of the pyro proxy levoglucosan and black carbon . To quote P Zennaro et al from their paper ” Fire in ice : two millennia of boreal forest fire history from the Greenland NEEM ice core ‘, Climate of the Past ,Oct 2014 :
    ” The [ megafire] peak at 342 CE contains by far the highest concentrations of both levoglucosan and [black carbon ] present in our datasets and corresponds to the largest fire event in the past 2000 years recorded by several charcoal records in the northern US and Canadian Rockies [ Brunelle et al ,2005 ; Hallet et al 2003 ] ” https://cp.copernicus.org/articles/10/1905/2014/cp-10-1905-2014.pdf

    I do not have the expertise , or access to refined high resolution ice core chronologies to explain the ammonium spike asynchrony in the lower chart of Figure 2 However the alignment is sufficiently compelling to warrant further scrutiny and tinkering from ice core researchers and paleo-climatologists . The approximate date of the American mid west bolide and conflagration can therefore be confidently narrowed to sometime between 342 CE and 383 CE .
    342CE is also intriguingly close to one of the sharp ‘blips’ [ Jonny’s ‘apparitions’ that we supposedly should have little confidence in ] in the H8 sequence of Franzen and Cropp’s Cobalt /REE peat mire index as the climate was deteriorating and the Roman Empire crumbling . The localized stratigraphical evidence for a meteor detonation that destroyed the Ohio River Valley Amerindian cultures compiled by Ken Tankersley and his colleagues is overwhelming.. Perhaps the best method for tightening the date lies in analysis of the ice cores.

  2. My initia reaction was that this earthwork was created in memory of the Bald Mountains impact (for which see “man and Impact in the Americas, 2005). This impact led to the destruction of the Mississippian peoples in the area which would become the Cherokee homeland.

    At the time of the climate collapse of 536 CE, the Algonquin stream (A mt DNA) of what would become the Shawnee people emigrated from the north, crossing Lake Erie. That emigration may account for the destruction levels that Tankersley has noted.

    Science progresses.

  3. HI Stuart,

    A couple of quick notes to bear in mind here. The Zennaro et al. paper was published in 2014, and as such use the NEEM dates of Sigl et al. (2013), those dates being tied to the erroneous GICC05 timescale (which has a chronological offset before AD 1100, the published dates being too old). Sigl et al. (2015) corrected this timescale (based upon cosmogenic markers in tree rings and ice cores, as well has historical documentation). Thus dates in the Zenarro et al. (2014) for the 4th century AD should be moved forward by 7-8 years, meaning their 342 Megafire date is actually around AD 349-50.

    I can see why you think there is an asynchrony in Figure 2, as at first glance I thought there was too, because our eyes are drawn to the massive ammonia spike (the one with a value in excess of 30 ng/g) in the late 300s. Closer inspection though shows there is no asynchrony between the Ammonia data (Figure 2 bottom) and the Black Carbon/Levoglucosan data above it. The ammonia spike that correlates with the BC/Levoglucosan spikes is to the right of the large (>30 ng/g) ammonia spike. This is confirmed in Table 1 of Zennaro et al. If you look at the ammonia concentration at “342” in Table 1, which is given a value of 15.83 ng/g and compare it to the ammonia data in Figure 2 of the paper you see that this value corresponds to the ammonia spike to the right of the large (>30 ng/g) ammonia spike.

  4. I observed Table 1 ….. I only meant a perceptible asynchrony in the juxtaposed ammonium [ It looks offset ] vis a vis the BC and levoglucosan values in Figure 2 …….Furthermore the black carbon chronology is sourced from the NEEM -2011 core adjacent to the deep NEEM core containing the ammonium and levoglucosan ….Yes are they are all one and the same event . The abnormal circa 350 CE megafire residues in the NEEM cores were almost certainly the fallout from the Ohio River Valley meteor blast and conflagration that may have extended into southern Canada and the Rockies .. The bolide may have been an inert stream relic that exploded in the atmosphere and not a chunk torn from a passing comet . Ethnographers , maverick talented researchers such as Bruce Massie EP Grondine and Native American lore keepers can now re-examine the old cataclysm myths of the Midwest Amerindian cultures to look for more clues. NASA has most definitely neglected and underestimated the impact hazard …Too fixated under Gavin Schmidt on Green ideology and climate change it would seem

    I see Jonny has not commented on the correlated [ 300 – 400 years ] H8 Cobalt /REE blip close to 350 CE in the “entire dataset” he received from Lars Franzen – apart from the missing data he belatedly admitted he did not analyze .

  5. The NEEM -2011-S1 core containing the black carbon values is a separate albeit adjacent column to the original deep NEEM core : ” BC was measured using a continuous ice core melter system ………in the 410 m NEEM -2011-S1 core collected adjacent to the deep NEEM core in 2011 ”

    Was the shorter adjacent NEEM – 2011-S1 core timescale adjusted forward precisely 7-8 years as well “Jonny “?

    At first glance the enormous ammonium , black carbon and levoglucosan spikes in Figure 2 seem to be conjunctive but that assumption is deceptive. To clarify , by asynchrony I meant there are two candidate dates visible in the Figure 2 datasets [ hence my prudent conjectural timeframe 342 CE – 383 CE ] that may be attributable to the Ohio River Valley cataclysm :

    [i] the 342 CE [ adjusted circa 350 CE ] event corresponding to the highest concentrations of the pyro -proxy levoglucosan and black carbon ‘present in the datasets’

    [ii] the later 300’s [ date uncertain ] standout ammonium pillar coinciding with another black carbon [ BCZ score 2 ] peak nudging 20 ng/g – slightly higher values than the registered 922 CE [ 930 ] peak .

    The conclusion of the Zennaro et al paper explains that ” Levoglucosan , NH4 and BC analyses in the NEEM ice cores provide a specific record of past biomass burning .Each biomass burning marker has a set of intrinsic strengths and limitations ,and so a combination of fire proxies results in a more robust reconstruction ” The circa 350 CE 15.83 NH4 value is too small to be of relevance as a bolide or megafire proxy …The prodigious ammonium spike to the left is the one of interest ..Both candidate dates – circa 350 CE and lets say circa 370 -380 CE – have two convergent megafire proxy peaks in the respective datasets .Hence the period of interest for determining the precise date of the Ohio River Valley impact : 342 CE [ 350 ] – 383 CE

    And to reiterate , the 4th century CE Hopewell impact is very close to one of the Cobalt /REE blips in Franzen and Cropp’s peat mire series just as the circa 1650 BC Jordan Valley air-burst that destroyed Dead Sea rim settlements is approximate to another Cobalt /REE peak that may be interpreted as one of Clube and Napiers ‘enhanced risk ‘ periods.

    ..I’m sure investigative efforts must be a matter of urgency for super – woke climate change obsessed space agency NASA under Gavin Schmidt who found time to advocate renaming the ‘Eskimo Nebulae ‘ and the Siamese Twin’s Galaxy

  6. Hi Stuart,

    Both the NEEM Deep core and the NEEM-2011- S1 timescales are tied to the GICC05 timescale, and so all published dates of these cores prior to July 2015 (the publication of Sigl et al. (2015), will be too old prior to circa AD 1100. In other words, the dates published in Zannaro et al. (2014) are all GICC05 timescale dates, and have not been corrected, and so must be moved forward 7-8 years in the the 4th century to better match a true calendar date.

  7. Sorry, the above anonymous comment is mine. I hit the post button before I remembered to put my name in the box.

  8. I apologise, Stuart, for the fact that I actually have a busy life outside the blog sphere and cannot devote whatever scarce free time that I may get to replying to every post, topic, comment and question on Cosmic Tusk. I am sorry if that is not satisfactory for you, but that’s the way it is.

  9. What a fabulously loaded question. That’s right up there with the likes of “Have you stopped beating your wife?”.

    As mentioned above (and elsewhere) I really do not have time to devote to this. I have replied out of courtesy, and answered your question about the NEEM Core timescales. I do not have time at this moment to get into protacted discussions, or into the nuanced arguments of chronological data, nor to dissect and critique what you, or I have said in previous posts. I know that’s what you want, but I simply do not have the time to engage with you, and I apologise for that. My posts are archived here for anyone to see and to judge on whether I have contradicted myself or not.

  10. ” My posts are archived here for anyone to see and to judge on whether I have contradicted myself or not ” .Oh but you have

    The Oldie but a Goodie thread Exhibit 1 : ” Lars was kind enough to send me his entire data set which I analyzed myself ”

    ” I was not provided the radiocarbon depth profiles or their tephrochronology analysis to verify their chronology ” In other words not the entire data set if you received it at all

    Exhibit 2 : ” Finally ,let us now turn to the presence of marine diatoms in the GISP2 core…..they have been found in a layer that Abbott et al date to 536 which would in fact be around 530 ….if the particles are not cosmic then the diatoms must have got there by a different mechanism …we can also propose other rare events . What about a large undersea eruption [ like the ‘rare event ‘ recently near Tonga ] ….of sufficient magnitude to inject sea water ….and thus diatoms into the atmosphere ,to be carried to Greenland ice cap ? ”

    ” So when you look in the correctly dated ice cores of Greenland and Antarctica ,there is no sulphate around AD 531 and so the AD 531 frost ring does not appear to have a volcanic origin ” 530 /531 CE ice layers are almost indistinguishable that far back in time . You ruled out a volcanic eruption yet proposed a ‘large undersea eruption ”

    Now either you were mentally tired or ,- as I suspect given you have not qualified and amended your arguments – you are deliberately dissembling

    Doublespeak : ” evasive ,ambiguous language that is intended to deceive or confuse ”

    “Jonny ” is also inclined to the Gish Gallop tactic – ” a type of logical fallacy ……that occurs when someone throws at you a myriad of half-truths and misleading statements in hopes of making their stance stronger ………The arguers aim is to quickly back their position with a large amount of ‘evidence ‘ .however it is typically hastily put together ,inaccurate and even irrelevant to the issue at hand ….the more arguments one can come up with ,and the vaguer they are ,the more effective the tactic becomes ” . https://fallacyinlogic.com/gish-gallop/

    For example : ” Now the reason to bring Antimony into the argument is not just to give an alternative potential variable for modelling the XDS spectra …….If lead from metallurgy can be transported to the Greenland ice cap then why not Tin and Antimony ? So one could hypothesis[e] that perhaps the grains that Abbott et al have identified as cosmic may actually be a signal of Tin and Antimony smelting/processing. One could also speculate that the iron rich particles …..may also have a human metallurgy origin ”
    Where is this parallel Antimony series if it is not a distractive non sequitur ? And why did Jonny comfortably discuss the Greenland ice core lead contaminant chronology but not anthropogenic lead deposition as a geochemical marker in the peat mire index ? [ That he has persisted in avoiding above ..Like some ‘taboo’] Furthermore, the Arctic lead residue datasets display a timescale depression – just as they do around the time of the Black Death and Antonine Plague – prior to the Justinian Plague outbreak and solar -veil years when barbarian tribes were over -running and ransacking the Roman Empire , millions died and industries were stagnating . This is difficult to reconcile with the observed 1600 % surge in particle volume at the start of Abbott et al’s 10 year window of study . What else is in the ice across the 6th century ? Abbott and her colleagues actually presented convincing evidence for the uniquely extraterrestrial features [ ie their ‘platy’ texture ] of the particulate assemblage in their 2014 paper that “Jonny’ neglected to acknowledge.

  11. Thank you, Mr. Howard, for bringing this drama to our attention back in October of 2021, when the paper by Tankersley, et al, was published by Research Gate, with the standard advisory that it had not yet been peer reviewed. The Washington Post article links to the same Research Gate publication, that has since been published seemingly intact under the imprint of Nature, after peer review by referees enlisted by Scientific Reports.
    Thanks also for providing the link to the Smithsonian Magazine article written by their correspondent Elizabeth Gamillo.
    It’s enlightening and humbling to plow through the meticulously prepared data that have been published by the various research teams investigating evidence of impacts and airbursts. Makes me appreciate better the dedication of those who have made the journey to completion of their dissertations.
    But it also underscores how much we depend on honesty and integrity in the process. It becomes clear in following the turbulent and sometimes acrimonious exchanges, that even the most respectable credentials do not always guarantee a person will be able to shed all pre-judgments in the course of re-tracing the steps of researchers whose conclusions and findings tend to overturn long-held articles of faith.
    The tragi-comic examples of Cope and Marsh remind us that personalities can sometimes drive the course of research as much as any other factor.

  12. Hi Will –

    If you think that’s bad, many people still refer to the Second Holocene Start Impact Event as the “YD Impact”, when the YD was separated by several thousand years from it. Knowledge of the First Holocene Start Impact Event is currently non existent among the unwashed.

    When I started working on the impact hazard in the 90’s, knowledge of recent asteroid and comet impacts was nil. At that time, I used Adomnan’s Life of Columba to try and disentangle volcanoes and impacts during this period. So I am quite pleased to see “vigorous” academic debate. I just wish I could sell refreshments. .

  13. The Levoglucosan value, the great fire, belongs to the cosmic impact in the Libyan sea at 365 AD. Zennoro is exactly 20 years too old in his paper, he is 20 years consistently too old calibrated for all his other peak events in his paper. Furthermore, if plenty of burned carbon were recovered in excavations, they could better do in age analysis of 14-C , then a huge spread of 130 years, a massif deficit, why is this? Anyway, there is not impact crater just a air blast without ground impact. For sure is that the Hopewell people were living over some 100s of miles, wiping out one place would not really male a hugh dent in the population. I rather bet that the end of Hopewell was at 700 – 750 AD, with the LALIA, the “antique little ice age” when agriculture over there in the North was impossible because of great cold and the connected short growing season.

  14. The Snake Den Mounds in Pickaway county have melted slag rock. I wonder if the rock is from the Southern Ohio air burst.

  15. Just one more question ‘ ” Jonny McAneney/ Anonymous ” , I seem to recall you quoting Duncan Steele’s Taurid stream calendrical precession rate of 22 days per millennium in a Cosmic Tusk comments thread……And yet in Victor Clube and Bill Napier’s Cosmic Winter the authors estimates are different : ” At present the Taurid meteors appear at night in middle and late November . Allowing for their slow orbital evolution and for the precession of equinox’s , one finds that going back in time they appeared about one week earlier per millennium assuming they derived mainly from Enckes Comet ……no great precision can be given since the structure is almost unknown ”

    22 days according to Steele’s calculations …. 7 days for the Clube/Napier model ….Which is it Jo ?

  16. Yes the accurate dating of impact events is crucial for human civilization …..As you can see I narrowed the Hopewell airburst dating probability range to 350 – 383 BCE just by analyzing the NEEM core black carbon ammonium and levoglucosan values ……….. You should familiarize yourself with the Straw Man fallacy ….I have never argued ” that a giant comet entering our solar system presents no possible threat ” Clearly 30 000 – 20 000 years ago the Taurid progenitor disintegrated and caused havoc in the inner planetary system ever since You either misinterpreted what I wrote or made that up and misrepresented me ….

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