Guest “geology lesson” by David Middleton
Fire from the Sky
Researchers find evidence of a cosmic impact that caused destruction of one of the world’s earliest human settlements
By Sonia Fernandez
Friday, March 6, 2020Before the Taqba Dam impounded the Euphrates River in northern Syria in the 1970s, an archaeological site named Abu Hureyra bore witness to the moment ancient nomadic people first settled down and started cultivating crops. A large mound marks the settlement, which now lies under Lake Assad.
But before the lake formed, archaeologists were able to carefully extract and describe much material, including parts of houses, food and tools — an abundance of evidence that allowed them to identify the transition to agriculture nearly 12,800 years ago. It was one of the most significant events in our Earth’s cultural and environmental history.
Abu Hureyra, it turns out, has another story to tell. Found among the cereals and grains and splashed on early building material and animal bones was meltglass, some features of which suggest it was formed at extremely high temperatures — far higher than what humans could achieve at the time — or that could be attributed to fire, lighting or volcanism.
[…]
Abu Hureyra lies at the easternmost sector of what is known as the Younger Dryas Boundary (YDB) strewnfield, which encompasses about 30 other sites in the Americas, Europe and parts of the Middle East. These sites hold evidence of massive burning, including a widespread carbon-rich “black mat” layer that contains millions of nanodiamonds, high concentrations of platinum and tiny metallic spherules formed at very high temperatures. The YDB impact hypothesis has gained more traction in recent years because of many new discoveries, including a very young impact crater beneath the Hiawatha Glacier of the Greenland ice sheet, and high-temperature meltglass and other similar evidence at an archaeological site in Pilauco, located in southern Chile.
[…]
UC Santa Barbara
The biggest problem with Younger Dryas impact crater hunters is their insistence on describing everything as evidence for their pet hypothesis. This is the most egregious example I have seen so far:
The YDB impact hypothesis has gained more traction in recent years because of many new discoveries, including a very young impact crater beneath the Hiawatha Glacier of the Greenland ice sheet…
The Younger Dryas fits right into a well-established warming and cooling cycle exhibited throughout the Northern Hemisphere during the final Pleistocene glacial stage. Approximately every 1,500 years, Northern Hemisphere, occasionally global, temperatures sharply rose (Dansgaard-Oeschger events) and then rapidly cooled back to full glacial stage levels. The cold episodes are called glacial stadials and the warm episodes are called glacial interstadials. The final pair was the Bølling–Allerød glacial interstadial and Younger Dryas glacial stadial. The Bølling–Allerød interstadial was particularly warm, as warm as the Little Ice Age in Central Greenland. Setting aside the fact that the Younger Dryas stadial doesn’t really require a unique explanation, some of the evidence for a significant Younger Dryas impact event is actually quite compelling. The platinum anomalies (Petaev et al., 2013 and Moore et al., 2017) comprise the first (and just about only) relatively unambiguous pieces of evidence for a significant bollide event(s) at, or near the transition from the Late Pleistocene Bølling–Allerød interstadial to the Younger Dryas stadial (AKA the Younger Dryas Boundary (YDB)). The GISP 2 anomaly (Petaev et al., 2013) is most compelling.
The most recent paper by the intrepid crater hunters alleges YDB impact evidence from an archaeological site at Abu Hureyra, Syria. For anyone interested, the full text is available. The paper cites Petaev et al., 2013, regarding a YDB platinum anomaly in the GISP2 ice core, as supporting evidence, which it isn’t. The paper also mentions the Hiawatha crater in Greenland. While it doesn’t specifically link it to the YDB, the UCSB press release does. The subject of this post is limited to the reasons why the GISP2 platinum anomaly and Hiawatha crater do not support any version of the YDB impact hypothesis.
GISP2 YDB Platinum Anomaly
In this paper, the term “airburst/impact” refers to a collision of a cosmic body with the Earth’s atmosphere, after which numerous smaller fragments may strike the ground forming transient surface craters. These studies propose that such an impact event triggered a cascade of secondary effects, including a brief impact winter and severe Younger Dryas (YD) climate change (span: ~12,800–11,500 cal BP)1,13,14, along with possible contributions to the megafaunal extinctions and human population declines23. Moore and Kennett24 concluded that impact-triggered climate change caused the prehistoric villagers at Abu Hureyra to transition from hunting/gathering to cultivation, indicative of earliest agriculture, one of the most significant cultural transformations in human history.
Moore, Andrew (not Christopher), et al., 2020
Petaev et al., 2013 comes just about as close as you can get, short of finding a crater, to unambiguous evidence of a significant YDB impact event. Unfortunately, it contradicts one of the favored hypotheses: The bolide triggered widespread fires, triggering a sort of nuclear winter, sinking Earth into the Younger Dryas cooling period.
Until the question about the nature of Pt-rich material and the means of its delivery to the ice is resolved, an extraterrestrial source of Pt appears likely. For example, the Pt anomaly could be explained by multiple impacts of an iron meteorite like Sikhote-Alin or Grant (21, 26); the former is a large crater-forming meteorite shower. Assuming a global anomaly, the 62.5-cm-thick ice layer with the average Pt concentration of 30 parts per trillion (ppt) (Fig. 1) would require an iron meteorite like Sikhote-Alin of ∼0.8 km in diameter to account for the Pt budget at the YDB. Because complete disintegration of such a large iron meteorite during its atmospheric passage seems unlikely, the event is expected to form a crater of a few kilometers in diameter. No such crater at YDB has been found so far.
The main conclusion of our study is the detection of an unusual event during the Bølling-Allerød–YD transition period that resulted in deposition of a large amount of Pt to the Greenland ice. The Pt anomaly precedes the ammonium and nitrate spike in the GISP2 ice core (2) by ∼30 y and, thus, this event is unlikely to have triggered the biomass burning and destruction thought to be responsible for ammonium increase in the atmosphere and the Greenland ice (11). Although the data do not allow an unambiguous identification of the Pt source, they clearly rule out a chondritic origin of Pt. One of the plausible sources of the Pt spike is a metal impactor with an unusual composition derived from a highly fractionated portion of a proto-planetary core.
Petaev et al., 2013
The YDB platinum anomaly is not consistent with a cometary or chondritic airburst. The platinum anomaly is consistent with a Pt-rich, Al-poor, Ir-poor iron meteorite, which would have left a significant crater. Furthermore, Pt anomalies have not been found in any other Greenland ice cores, nor has any ejecta material been observed in any Greenland ice cores.
So, where’s the YDB crater?
Hiawatha Crater
What he brought home clinched the case for a grand discovery. Hidden beneath Hiawatha is a 31-kilometer-wide impact crater, big enough to swallow Washington, D.C., Kjær and 21 co-authors report today in a paper in Science Advances. The crater was left when an iron asteroid 1.5 kilometers across slammed into Earth, possibly within the past 100,000 years.
Though not as cataclysmic as the dinosaur-killing Chicxulub impact, which carved out a 200-kilometer-wide crater in Mexico about 66 million years ago, the Hiawatha impactor, too, may have left an imprint on the planet’s history. The timing is still up for debate, but some researchers on the discovery team believe the asteroid struck at a crucial moment: roughly 13,000 years ago, just as the world was thawing from the last ice age. That would mean it crashed into Earth when mammoths and other megafauna were in decline and people were spreading across North America.
The impact would have been a spectacle for anyone within 500 kilometers. A white fireball four times larger and three times brighter than the sun would have streaked across the sky. If the object struck an ice sheet, it would have tunneled through to the bedrock, vaporizing water and stone alike in a flash. The resulting explosion packed the energy of 700 1-megaton nuclear bombs, and even an observer hundreds of kilometers away would have experienced a buffeting shock wave, a monstrous thunder-clap, and hurricane-force winds. Later, rock debris might have rained down on North America and Europe, and the released steam, a greenhouse gas, could have locally warmed Greenland, melting even more ice.
The news of the impact discovery has reawakened an old debate among scientists who study ancient climate. A massive impact on the ice sheet would have sent meltwater pouring into the Atlantic Ocean—potentially disrupting the conveyor belt of ocean currents and causing temperatures to plunge, especially in the Northern Hemisphere. “What would it mean for species or life at the time? It’s a huge open question,” says Jennifer Marlon, a paleoclimatologist at Yale University.
A decade ago, a small group of scientists proposed a similar scenario. They were trying to explain a cooling event, more than 1000 years long, called the Younger Dryas, which began 12,800 years ago, as the last ice age was ending. Their controversial solution was to invoke an extraterrestrial agent: the impact of one or more comets. The researchers proposed that besides changing the plumbing of the North Atlantic, the impact also ignited wildfires across two continents that led to the extinction of large mammals and the disappearance of the mammoth-hunting Clovis people of North America. The research group marshaled suggestive but inconclusive evidence, and few other scientists were convinced. But the idea caught the public’s imagination despite an obvious limitation: No one could find an impact crater.
Proponents of a Younger Dryas impact now feel vindicated. “I’d unequivocally predict that this crater is the same age as the Younger Dryas,” says James Kennett, a marine geologist at the University of California, Santa Barbara, one of the idea’s original boosters.
Science Magazine, 2018
There is little doubt that this is an impact crater, a fairly big one. There is also little doubt that it is, geologically speaking, fairly young, almost certainly less than 2 million years old. There’s just one problem with it having occurred at the onset of the Younger Dryas: There is no evidence that the ice sheets were affected.
The full text of Kjær et al., 2018 is also available. The paper is well-worth reading. While it does not assert that the impact occurred at the YDB, it notes that the radar imagery below the Holocene is “either poorly expressed or absent stratigraphic layering”. We can see in Figure S5, from the Supplemental Material, that the Younger Dryas reflector is not present in at the location of the nearest ice core, Camp Century, and that the Pleistocene ice is poorly imaged. A similar pattern is observed at the most distant ice core, DYE-3.
Radar imaging of the Younger Dryas and Pleistocene is poor at both outboard (Camp Century & DYE-3) core locations. These are also where the most ice has been lost since the end of the Pleistocene.
A massive impact 13-14 ka would have left a very clear mark in the Late Pleistocene-Early Holocene ice record, however there is no indication of a disruptive event in any of the ice cores, not even the nearby (~130 miles) Camp Century…
Radiostratigraphy (MacGregor et al, 2015) indicate there there is a continuous ice column from 11.7 ka down to 29 ka very close to Hiawatha crater, and the edge of the full Holocene to Last Glacial Maximum column is no different anywhere else along the northern edge of the Greenland Ice Sheet.
The closest Greenland ice core to Hiawatha, Camp Century, encountered a full section through the Last Glacial Maximum, including the Younger Dryas. It exhibits a nearly perfect correlation to the most distant, Dye 3.
Furthermore, the area near Hiawatha crater was covered by ice up until at least 10,000 years ago (Dyke, 2004). There is no indication that this portion of the Greenland coastline was uncovered any earlier than about 10,000 years ago. The Hiawatha impact most likely occurred, prior to the onset of the final Pleistocene glacial stage, possibly during the Eemian interglactial stage, more likely in an earlier warm interglacial stage.
So, while it is young, geologically speaking, the Hiawatha impact predated the Younger Dryas, most likely before the Last Glacial Maximum.
Proponents of the YDB impact theory would be better served by sticking to the less ambiguous evidence. The fact that they insist on hammering every “square peg into a round hole” undercuts their cause… Which is another problem, science shouldn’t have causes.
References
Kjær, Kurt, Larsen, Nicolaj, Binder, Tobias, Bjørk, Anders, Eisen, Olaf, Fahnestock, Mark & Funder, Svend & Garde, Adam & Haack, Henning & Helm, Veit, Houmark-Nielsen, Michael, Kjeldsen, Kristian, Khan, Shfaqat, Machguth, Horst, Mcdonald, Iain, Morlighem, Mathieu, Mouginot, Jeremie’ Paden, J., Waight, Tod & MacGregor, Joseph. (2018). “A large impact crater beneath Hiawatha Glacier in northwest Greenland”. Science Advances. 4. eaar8173. 10.1126/sciadv.aar8173.
MacGregor, J. A., Fahnestock, M. A., Catania, G. A., Paden, J. D., Prasad Gogineni, S., Young, S. K., Rybarski, S. C., Mabrey, A. N., Wagman, B. M. and Morlighem, M. ( 2015), “Radiostratigraphy and age structure of the Greenland Ice Sheet”. J. Geophys. Res. Earth Surf., 120: 212– 241. doi: 10.1002/2014JF003215.
Moore, A.M.T., Kennett, J.P., Napier, W.M. et al. Evidence of Cosmic Impact at Abu Hureyra, Syria at the Younger Dryas Onset (~12.8 ka): High-temperature melting at >2200 °C. Sci Rep 10, 4185 (2020). https://doi.org/10.1038/s41598-020-60867-w
Moore, C., West, A., LeCompte, M. et al. Widespread platinum anomaly documented at the Younger Dryas onset in North American sedimentary sequences. Sci Rep 7, 44031 (2017). https://doi.org/10.1038/srep44031
Petaev, Michail I., Shichun Huang, Stein B. Jacobsen, Alan Zindler. “Large Pt anomaly at the onset of the Younger Dryas”.
Proceedings of the National Academy of Sciences Aug 2013, 110 (32) 12917-12920; DOI: 10.1073/pnas.1303924110
Day 13 of America Held Hostage by ChiCom-19
Since Harris County (Houston) is now locked down like Dallas, pretty well the entire company is working from home. Because oil companies are deemed “critical infrastructure”, we can go to the office if necessary, we just have to get a letter from the company, just in case the “authorities” stop us and want to see our permission slips… Is this next?
In the meantime…
| Dallas County | CHICOM-19 | |
| Population | Cases | Deaths |
| 2,637,772 | 367 | 7 |
| % of population with | 0.0139% | 0.00027% |
| % without | 99.9861% | 99.9997% |
| % without rounded | 100.0% | 100.000% |
The county is ramping up drive-through testing. It’s still mostly limited to people with symptoms, medical professionals, first responders and Parkland Hospital (the county hospital) patients and employees. About 10% are testing positive. I’m still working on a “when a coronavirus gets its lime” meme.
Featured Image
I work for an hour on a post and it just disappears. If this keeps up I’ll have to give up on WUWT. –AGF
David,
I’m with you on the overboard response to a tiny number of cases. In my county, we currently have 96 confirmed COVID-19 cases and 1 death. The estimated population of the county is 658,000, meaning that approximately .014% are confirmed to be infected, similar to yours. Be still, my beating heart! Even if the real number is 10 times that, it’s hardly cause for alarm, yet people around me are genuinely alarmed.
Middleton, if the cavalry were coming for your motley band you would take target practice at their horses. The Younger Dryas Impact Hypotheses knocks the legs out of the fearsome claim that “abrupt change” results from mysterious “tipping points.” It also demonstrates that (while I do not fear monger on either subject) that concern for +1.4 degrees over the last 150 years is like arguing about the radio station while sitting on the train tracks.
Ill address some of your technical misunderstandings of the Kjaer paper in separate comments. But for this one I’d like to point out how your jihad on the YDIH is shamefully counter-productive to your own mission, and your readers mission, to unravel the sham that is climate fear communication.
I was at AGU 2010 in San Francisco when the high priest and “grandfather of climate science” Wally Broecker’s position regarding the YD impact was quite clear. He addressed the YDIH team and assembled and struck Comet in his slides as the cause of the climate period he had built his career studying. It was devastating to our study of the period. (I have over 600 co-author citations on the YDIH.)
In fact, my very first blog was concerned that conference: https://cosmictusk.com/hello-world-2/
However, not long before he died last year, Wally Broecker sent a memo to his team at Lamont-Doherty admitting that his iconic period – the Younger Dryas – was indeed the result of a globe cooling impact.
He said in the memo,
“Although I don’t for a minute believe that this impact did in the mammoths and the Clovis people, I do think that it triggered the YD.”
See Broecker’s entirely unreported internal memo here: https://cosmictusk.com/wally-broecker-says-a-cosmic-impact-caused-the-younger-dryas/
To say this was a profound reversal is an understatement.
So, here’s my question: If an octogenarian at the end of a hagiographic climate career can admit he was dead wrong about his most important claim – which had been pimped in print, film and TV as a fearful example of abrupt climate change – why can’t a climate truth pajama blogger like you?
And if you support the traditional understanding of the YD as an earthly forced period – but were proven wrong – wouldn’t that conclusion nonetheless further your efforts to base climate science on facts and not hysterical anti-science fearmongering?
Your effort to take down an enemy of your enemy with unbalanced, drive-by attacks is not helpful to your cause or to science. You have joined the legion of climate fear pimps that regularly attack the (damn difficult to get published) YD impact science. Both you and Anthony need to sit down and carefully read our heretical work (see last sentence), perhaps reach out to some of the authors (we don’t hide our work or data), and explore this theory as an opportunity to “change the conversation.”
Or, at the very least, lower your rifle and see if we can help save you.
(As a matter of record, I am a conservative climate skeptic, a position which is financially and politically dangerous for me. As CEO of http://www.restorationsystems.com, one of the world’s largest environmental credit traders, I have more to gain from “carbon trading” than anyone on earth — and I wouldn’t sell an ounce. I worked in the US Senate for six years (three for Jesse Helms) and three in the Environment and Public Works Committee. I fought the battle for eco-realism on the front lines, preceding Marc Morano of Climate Depot at that Committee. I have an extensive background in the difficult world of truthful environmental science messaging and maintain every YDIH paper and a comprehensive bibliography at my pajama blog here: https://cosmictusk.com/younger-dryas-impact-hypothesis-bibliography-and-paper-archive/)
(whoops caught a typo)
Middleton, if the cavalry were coming for your motley band you would take target practice at their horses. The Younger Dryas Impact Hypotheses knocks the legs out of the fearsome claim that “abrupt change” results from mysterious “tipping points.” It also demonstrates that (while I do not fearmonger on either subject) concern for +1.4 degrees over the last 150 years is like arguing about the radio station while sitting on the train tracks.
Ill address some of your technical misunderstandings of the Kjaer paper in separate posts. But for this one I’d like to point out how your jihad on the YDIH is shamefully counter-productive to your own mission, and your readers mission, to unravel the sham that is climate fear communication.
I was at AGU 2010 in San Francisco when the high priest and “grandfather of climate science” Wally Broecker’s position regarding the YD impact was quite clear. He addressed the YDIH team and assembled and struck Comet in his slides as the cause of the climate period he had built his career studying. It was devastating to our study of the period. (I have over 600 co-author citations on the YDIH.)
In fact, my very first blog concerned that conference: https://cosmictusk.com/hello-world-2/
However, not long before he died last year, Wally Broecker sent a memo to his team at Lamont-Doherty admitting that his iconic period – the Younger Dryas – was indeed the result of a globe cooling impact.
He said in the memo,
“Although I don’t for a minute believe that this impact did in the mammoths and the Clovis people, I do think that it triggered the YD.”
See Broecker’s entirely unreported internal memo here: https://cosmictusk.com/wally-broecker-says-a-cosmic-impact-caused-the-younger-dryas/
To say this was a profound reversal is an understatement.
So, here’s my question: If an octogenarian at the end of a hagiographic climate career can admit he was dead wrong about his most important claim – which had been pimped in print, film and TV as a fearful example of abrupt climate change – why can’t a climate truth pajama blogger like you?
And if you support the traditional understanding of the YD as an earthly forced period – but were proven wrong – wouldn’t that conclusion nonetheless further your efforts to base climate science on facts and not hysterical anti-science fearmongering?
Your effort to take down an enemy of your enemy with unbalanced, drive-by attacks is not helpful to your cause or to science. You have joined the legion of climate fear pimps that regularly attack the (damn difficult to get published) YD impact science. Both you and Anthony need to sit down and carefully read our heretical work, perhaps reach out to some of the authors (we don’t hide our work or data), and explore this theory as an opportunity to “change the conversation.”
Or, at the very least, lower your rifle and see if we can help save you.
(As a matter of record, I am a conservative climate skeptic, a position which is financially and politically dangerous for me. As CEO of (www.restorationsystems.com) I have more to gain from “carbon trading” than anyone on earth — and I wouldn’t selling an ounce for $10,000. I worked in the US Senate for six years (three for Jesse Helms) and three in the Environment and Public Works Committee. I fought the battle for eco-realism on the front lines, preceding Marc Morano of Climate Depot at that Committee. I have an extensive background in the difficult world of truthful environmental science messaging and maintain every YDIH paper and a comprehensive bibliography at my blog http://www.cosmictusk.com)
This post is about the Hiawatha Crater and Pt anomalies associated with the YDB, the closest things to unambiguous evidence of an impact…. Not bizarre conspiracy theories. I am happy to discuss the subject of this post. If you want to write a rambling narrative on hammering square pegs into round holes, please submit it as a post. Anthony is usually open to publishing guest posts and WUWT has posted numerous articles both supporting and criticizing the YDIH. If asked, I would certainly recommend publishing your submission.
YDIH is totally unrelated to the causes of modern climate change or cyclical Quaternary changes. So the “enemy of your enemy” bit is beyond bizarre. Science is not about picking sides or supporting causes.
Broeker also acknowledged back in 2000 that his thermohaline circulation catastrophe theory was probably wrong because Bond noted that the millennial scale fluctuations continued on into the Holocene, albeit in a muted fashion.
Note the pattern in the GISP2 ice core:
The most anomalous feature is not the Younger Dryas stadial. It’s the preceding Bølling–Allerød interstadial. No one knows for certain what drove the ~1,500 year Late Pleistocene climate oscillation. The Younger Dryas is simply not anomalous in the context of the final Pleistocene glacial stage.
Except that ~250 species went extinct. You are rallying the wise to defend the ignorant. Just because you may have personal history of calling the YD unexceptional, does not undermine the evidence something profoundly significant happened at that moment. That’s why we split geological epochs there, do you use the terms Holocene and Pleistocene? To say nothing significant happened ~12,877 years ago may be an early trope of climate communication, but it does trump the fact that very few people agree with you, or mammoths.
Except that ~250 species went extinct. You are rallying the wise to defend the ignorant. Just because you may have a personal history of calling the YD unexceptional, does not undermine the evidence something profoundly significant happened at that moment. That’s why we split geological epochs there long before climate hysteria. Do you use the terms Holocene and Pleistocene? To say nothing significant happened ~12,877 years ago may be an early trope of your climate communication, but it does not trump the fact that very few people agree with you — or mammoths.
Is the hypothesis that an impact caused the Younger Dryas? Or that an impact might have played a role in some extinctions? It seems to frequently change.
While the Younger Dryas and the transition from the last Pleistocene glacial stage to the current interglacial stage (the Holocene) may have been unremarkable from a climatology perspective, about 90 genera of megafauna (mammals weighing at least 44 kg) became extinct during the transition from the Pleistocene to the Holocene (Late Quaternary).
The Late Pleistocene-Early Holocene megafauna extinctions took place over 10’s of thousands of years at different times on different continents (Koch & Barnosky, 2006).
“Australia lost 14 of its 16 genera of Pleistocene mammalian megafauna along with “all megafaunal reptiles” (Koch & Barnosky, 2006). By 40,000 years ago, Australia had already lost more than 90% its larger species (Prideaux et al., 2010).
North American (Rancholabrean) extinctions appear to have occurred much later and possibly in at least two phases. While 16 of 35 Rancholabrean genera extinctions took place during the terminal Pleistocene (~2,000 yr period coincident with the Younger Dryas), the other 19 genera disappeared from the North American fossil record thousands of years earlier (Faith & Surovell, 2009).
2,000 years is a geological blink of the eye. Something catastrophic may have happened in North America during the terminal Pleistocene. This was also when the Folsom culture replaced the Clovis culture. A bolide is certainly a possibility in explaining some of the Rancholabrean extinctions. The Pt anomalies, particularly the one in the GISP2, provide strong evidence that a significant, crater-forming iron meteoroid/asteroid impact event occurred at YDB time.
https://wattsupwiththat.com/2018/05/14/poking-a-hole-in-the-latest-younger-dryas-impact-paper-uniformitarian-impact-craters-part-trois/
Much of the evidence cited in the various YDIH papers could be evidence of an impact, but it is ambiguous – subject to a wide range of interpretations.
https://wattsupwiththat.com/2018/06/27/the-single-biggest-problem-with-the-younger-dryas-impact-hypothesis-uniformitarian-impact-craters-part-cinq/
Some of the “evidence” cited is just crackpot psuedo-science.
https://wattsupwiththat.com/2018/04/25/uniformitarian-impact-craters-same-as-it-ever-was/
https://wattsupwiththat.com/2018/05/03/uniformitarian-impact-craters-part-deux-carolina-bays-edition/
And has been pointed out so many times here, wherever people go, big animals disappear in a hurry: in Australia, North America, South America, New Zealand, Madagascar, Wrangel Island, Crete, Komodo, etc. It must be those big game diseases the newcomers carry. –AGF
Funny since Africa, the continent with the longest continuous human presence, is the only one that retains its diversity of megafauna…
Of course. In Africa, and to a lesser extent in Asia, humans and animals evolved together. Did Africans eat elephants? –AGF
Humans and megafauna evolved together in Africa. From about 4 MYA to about 1.4 MYA, they hunted our ancestors, that all changed when Homo erectus started making stone tools…
https://owlcation.com/stem/The-African-Megafauna
–
The African climate and landscape wasn’t as seriously impacted by Pleistocene glacial cycles as North America, Europe and Asia were. When humans began spreading into the Americas, the megafauna would have already been experiencing habitat disruptions related to deglaciation, further complicated by the Bølling-Allerød interstadials and Dryas stadials. Our ancestors in Europe, Asia and the Americas benefited from more advanced weapons and tools, improved hunting methods and, perhaps most importantly, domesticated wolves (AKA dogs). With these advantages, they ran headlong into what were likely limited populations of megafauna, with no instinctive fear of humans.
Humans weren’t the sole cause of the megafauna extinctions… We were more like the “straw that broke the Camelops’ back.
Yeah, I know, I am since 1997 “the Carolina Bay man”. And still I believe those features are relatively poor evidence for the #YDIH, which more than shared by the lead authors and why they discarded the bays as we make the better case — more than a decade later. Science doesn’t require a perfect first draft. (Nonetheless, Carolina Bays are adequately explained, even by you, David). The unambiguous evidence is over 100 sites on multiple continents presenting material at well dated strata that could not be without hellish temps >2200 C. That’s a fact and probably why in your post above, you lead with a sensational reporting of the fact, but do not address the journal article that inspired the news article. And turn to bays and craters not featured in our papers.
I know how it is, I don’t read a lot of papers that disagree with my beliefs, but then again I don’t then proceed to write drive by posts without mention of the papers I didn’t read. You, Anthony and Morano et al. need to drop back a bit on this subject and read the papers, and the quality of the critiques, much more carefully. It is in your interest.
And mine.
I doubt you are open minded, David, but perhaps your misinformed readers are. Here is a post on how I perceive the relationship between “global warming” and the Younger Dryas Impact Hypothesis: https://cosmictusk.com/science_communicators_global_warming_hiawatha_crater_greenland_younger_dryas_cosmic_tusk/
EMP? I’ll let the Air Force worry about that. If an A-bomb fries my laptop I’ll have worse things to worry about than EMP. Superstar Bill Nye? They don’t come any dumber. –AGF
Good work, Mr. Middleton, and thanks for the bit on African paleontology. As for the climate contribution to megafauna extinction, it reminds me of the war for oil myth: it’s never explained whether the motivation is keep the price of gas high or low, that is, whether to benefit Big Oil or the gas guzzling consumers. Likewise the assumption that a warming climate was detrimental to mammoths and the dozens of other species that disappeared over a few millennia doesn’t make much sense to me; what was bad for the woolly mammoth should have been good for the Columbian mammoth and vice versa if temperature were the prime consideration, and if habitat, the same should go for mammoths versus mastodons.
Woolly mammoths disappeared from Wrangel Island at around the date of the first Eskimo archeological site, and a thousand years earlier on St. Paul Island, maybe when the Aleuts came around. Channel Island mammoths disappeared along with those on the mainland, not at all safe from the arrival of the mainlanders. Big and little elephants went extinct on islands in the Mediterranean and Indonesia, usually in association with human colonization, or at least modern (neolithic or thereabouts) human colonization. And the same goes for all the other megafauna that disappeared in Australia and South America. Blaming it even a little on climate change seems like politically correct hand waving: those noble savages were worthy caretakers of the land, nothing like us moderns.
But the pattern is clear; when the hunter moves in the hunted move out. Regards, –AGF
Yeah, I know, I’m the “Carolina Bay guy” since 1996. And still I believe those features are relatively poor evidence for the #YDIH, which more than shared by the lead authors and why they discarded the bays as we make the better case — more than a decade later. Science doesn’t require a perfect first draft. (Nonetheless, Carolina Bays are inadequately explained, even by you, David).
The unambiguous evidence is over 100 sites on multiple continents presenting microscopic and atomic materials at well dated strata that could not be, without hellish temps >2200 C. That’s a fact and probably why in your post above, you lead with a sensational reporting of the fact, but do not address the journal article that inspired the news article. And turn to bays and craters not featured in our papers.
I know how it is, I don’t read a lot of papers that disagree with my beliefs, but then again I don’t proceed to write drive by posts without mention of the papers I didn’t read. You, Anthony and Morano et al. need to drop back a bit on this subject and read the papers, and the quality of the critiques, much more carefully. It is in your interest and mine.
George,
I have written a lot of WUWT posts on this subject. I have read and referenced many, if not most, of the papers supporting and criticizing the YDIH. Each post generally deals with a specific aspect because…
“It is beyond the scope of this study to present” everything.
And…
In each post, I highlight a specific “experiment” that failed.
Petaev et al., 2013 and, to a lesser extent, Moore (Christopher) et al., 2017 pretty conclusively demonstrate that a significant impact event occurred at or near YDB time. Scoria like objects (SLO), basically volcanic glass, also support an impact, or impacts, near YDB time. Hiawatha Crater is a clear example of a relatively large, geologically young impact crater, probably older than 50,000 years ago and almost certainly younger than 2 million years ago. The timing of at least half of the Rancholabrean extinctions is also consistent with a catastrophic event.
The YDIH papers have presented evidence of biomass burning and potentially high temperature fires. However, this evidence is ambiguous. It has been interpreted in other ways. Almost all of the YDB sites have low chrono-stratigraphic resolution. The site with the highest chrono-stratigraphic resolution, the GISP2 ice core, clearly shows that the biomass burning occurred about 30 years after the impact, therefore the impact didn’t cause the biomass burning. Furthermore, like the Younger Dryas itself, the YDB biomass burning was not anomalous…
https://wattsupwiththat.com/2018/06/27/the-single-biggest-problem-with-the-younger-dryas-impact-hypothesis-uniformitarian-impact-craters-part-cinq/
David, I am having trouble understanding the central claim of your post, which I have read a dozen times. Are you saying that, since the ice cores distant from Hiawatha still show the YD and layed ice above and below, this means there was no impact at the YD-start? Is your underlying assumption here any impact would have removed the ice across the entire island? Help me out.
I’d add an anecdotal understanding that Kjaer et al. believed the crater dated to 12.9 based on the remaining ice at the location being, in their informed opinion, no older than 12.9. It is heard the Science reviewers struck all 27 original references to the YDIH, and not one remained, which is clearly suppressive. A paper such as this should be allowed to discuss whether their evidence comports with other published theories. But no, it endures the same repression encountered by evidence which undermines AGW. Here is the author of the Science magazine popular article on difficulties encountered by the Kjaer et al. https://cosmictusk.com/intrigue-at-science/