From the University of California at Santa Barbara -By Julie Cohen |
Most of North America’s megafauna — mastodons, short-faced bears, giant ground sloths, saber-toothed cats and American camels and horses — disappeared close to 13,000 years ago at the end of the Pleistocene period. The cause of this massive extinction has long been debated by scientists who, until recently, could only speculate as to why.
A group of scientists, including UC Santa Barbara’s James Kennett, professor emeritus in the Department of Earth Science, posited that a comet collision with Earth played a major role in the extinction. Their hypothesis suggests that a cosmic-impact event precipitated the Younger Dryas period of global cooling close to 12,800 years ago. This cosmic impact caused abrupt environmental stress and degradation that contributed to the extinction of most large animal species then inhabiting the Americas. According to Kennett, the catastrophic impact and the subsequent climate change also led to the disappearance of the prehistoric Clovis culture, known for its big game hunting, and to human population decline.
In a new study published this week in the Journal of Geology, Kennett and an international group of scientists have focused on the character and distribution of nanodiamonds, one type of material produced during such an extraterrestrial collision. The researchers found an abundance of these tiny diamonds distributed over 50 million square kilometers across the Northern Hemisphere at the Younger Dryas boundary (YDB). This thin, carbon-rich layer is often visible as a thin black line a few meters below the surface.
Kennett and investigators from 21 universities in six countries investigated nanodiamonds at 32 sites in 11 countries across North America, Europe and the Middle East. Two of the sites are just across the Santa Barbara Channel from UCSB: one at Arlington Canyon on Santa Rosa Island, the other at Daisy Cave on San Miguel Island.
“We conclusively have identified a thin layer over three continents, particularly in North America and Western Europe, that contain a rich assemblage of nanodiamonds, the production of which can be explained only by cosmic impact,” Kennett said. “We have also found YDB glassy and metallic materials formed at temperatures in excess of 2200 degrees Celsius, which could not have resulted from wildfires, volcanism or meteoritic flux, but only from cosmic impact.”
The team found that the YDB layer also contained larger than normal amounts of cosmic impact spherules, high-temperature melt-glass, grapelike soot clusters, charcoal, carbon spherules, osmium, platinum and other materials. But in this paper the researchers focused their multi-analytical approach exclusively on nanodiamonds, which were found in several forms, including cubic (the form of diamonds used in jewelry) and hexagonal crystals.
“Different types of diamonds are found in the YDB assemblages because they are produced as a result of large variations in temperature, pressure and oxygen levels associated with the chaos of an impact,” Kennett explained. “These are exotic conditions that came together to produce the diamonds from terrestrial carbon; the diamonds did not arrive with the incoming meteorite or comet.”
Based on multiple analytical procedures, the researchers determined that the majority of the materials in the YDB samples are nanodiamonds and not some other kinds of minerals. The analysis showed that the nanodiamonds consistently occur in the YDB layer over broad areas.
“There is no known limit to the YDB strewnfield which currently covers more than 10 percent of the planet, indicating that the YDB event was a major cosmic impact,” Kennett said. “The nanodiamond datum recognized in this study gives scientists a snapshot of a moment in time called an isochron.”
To date, scientists know of only two layers in which more than one identification of nanodiamonds has been found: the YDB 12,800 years ago and the well-known Cretaceous-Tertiary boundary 65 million years ago, which is marked by the mass extinction of the dinosaurs, ammonites and many other groups.
“The evidence we present settles the debate about the existence of abundant YDB nanodiamonds,” Kennett said. “Our hypothesis challenges some existing paradigms within several disciplines, including impact dynamics, archaeology, paleontology and paleoceanography/paleoclimatology, all affected by this relatively recent cosmic impact.”
– See more at: http://www.news.ucsb.edu/2014/014368/nanodiamonds-are-forever#sthash.Jz8DHJU3.dpuf
h/t to David Hagen.
The historical temperature graph at top, if accurate, shows the Younger Dryas could not be an impact event as the temperate drop was in stages over hundreds of years — an impact event would be abrupt. A sensible cause would be that the Bering Strait opened up giving the Pacific access to the totally frozen Arctic ocean, and when an undersea current connected the Pacific and the Atlantic underneath the miles-thick Arctic ice cap, then the oceans were inundated with new cold water which caused the cooling of the Younger Dryas. Thus the stages of the Younger Dryas shows the progress of that progressive melting out of the Arctic ice.
As for large animals, it astounds me how scientists are still looking for fairy tales to explain the mass deaths, when it was obviously human hunting. Where people went, the large animals were hunted to extinction — this is not hard. Of course the Clovis hunting culture and the large animals vanished at the same time. Here in NZ there is the same pattern: the Maori arrived c1100 and their first culture is known as the “moa hunter” culture as they hunted the native giant birds. About 300 years later the moa went extinct and the “moa hunter” culture ended. This is not hard.
By the way, the historical temperature graph at top mis-identified the MWP, it’s the next little hill to the right.
Don’t be too hasty. That “temperature” graph is not measured temperature. It is INFERRED. And not just the temps, but the timing also, all of it is VERY low resolution. Ice cores CANNOT DO high resolution – i.e., 200 years.
So don’t think that those curves are real. Even the data points – the line you see? It can be doing all sorts of things in between the data points as they’ve inferred from the 18O proxies. Most of these have straight lines and when it drops really fast, and the next point is 200 years later – did it drop even MORE straight down from the upper point? Or did it go flat first an THEN drop straight down? The LINE is a guess, when you start looking at short time periods. When you zoom in. YOU can zoom in, but the data can’t.
As to the humans hunting EVERY single mammoth on the ENTIRE continent –
(Most people don’t know most of this…)
1. 95% of Clovis people lived in the SE USA (based on the number of Clovis sites, which are QUITE numerous)
2. There are ZERO mammoth kill sites in the SE USA.
3. Wouldn’t you think that they would have killed afew mammoths near where they lived?
4. Why would they go out to Arizona and Montana from Georgia or Alabama, just to kill a 5-ton animal – to carry 3 tons home? ON FOOT?
5. There are at last count FOURTEEN Clovis kill sites.
6. N America is like 98 MILLION square miles.
7. Clovis entire history in the world only lasted about 250 years.
8. Lifespans back then were about 25 years.
9. The Overkill Hypothesis was thought of when it was assumed that Clovis ONLY hunted and ate Mammoths and other megafauna.
10. Anthropologists only now are discovering that Clovis hunted and ate rabbits and deer and elk and bear and foxes and raccoons, etc. They ARE revisiting their Mammoth extinction machine understanding of Clovis.
11. Clovis points did NOT come from over the land bridge at Beringia. The tool technology in NE Siberia is another tech altogether.
12. The only close relative to the CLovis point is the Solutrean point from Spain and France. As long as the Clovis Barrier existed (saying that no one was in the Americas before Clovis at 13,300 years ago) there was a 5,000 year gap between Solutrean points and humans in the New World. Since 1997, when the Clovis barrier was broken, human evidence in the New World has been pushed back to more than 20,000 years – about a 2,000 years overlap with Solutrean points – plenty of time for Clovis to develop from Solutrean. So now there are researchers who assert that the Solutrean point came with people from Europe, and the people came much earlier. And if they did, they would have most naturally come to the SE USA – right where we find 95% of the Clovis sites.
So, don’t be so certain. Evidence is coming up all the time that keeps changing our understanding of the settlement of the New World and about Clovis.
Verbiage is no substitute for logic. Consider the Petri dish if you think the North American continent is “vast” — no more vast than is the Petri dish to a single yeast bacterium which fills it up in a day. As I said, “this is not hard” — full stop.
“Lifespans back then were about 25 years.”
That’s an average (and a very low estimate I find dubious, to begin with: most papers give 34 or 35 average) between a big peak at the range 0-5 and a rising tail beyond the age of 60. Reconstructed modal age from primitive hunter-gatherer is 62 to 64 years old. 80-years-old were merely uncommon.
Similar story in Australia:
“New evidence based on accurate optically stimulated luminescence and uranium-thorium dating of megafaunal remains suggests that humans were the ultimate cause of the extinction of megafauna in Australia. The dates derived show that all forms of megafauna on the Australian mainland became extinct in the same rapid timeframe — approximately 46,000 years ago …” (Wiki).
Seriously? This is news? Otto Muck detailed the event over 50 years ago.
http://www.amazon.com/The-Secret-Atlantis-Otto-Muck/dp/0006355587
This answered all the questions – why has it been supressed?
Major upsets to the world like this one would not be a comet. More likely a glancing blow from something bigger and a shower of accompanying debris. There was a period where humans almost became extinct, being adaptable as we are the event must have been severe and affected the entire globe.
Sure. And comet Shoemaker-Levy 9 didn’t hit Jupiter in 1994. Comets never hit planets. Everybody knows that.
Except Jupiter has been hit by two other comets.
Something bigger? They can’t even find the crater for THIS one.
Actually, I think it is MUCH more likely to be a big, solid meteor. But one as big as the biggest piece of Shoemaker-Levy would do us in. How big was that? 1.3 km. And that WAS a comet.
It’s plume was bigger than Earth.
And there were THREE of them of 1 km or bigger. Three would do us in.
For the large impact area with no crater, it could have been the near passing of one of the gas planets of an inbound large loose comet that was gravitationally fragmented into hundreds of thousands of smaller pieces, that impacted the earth over several hours upon arrival, starting in the SW USA/Mexico area moving North East as the earth revolved and the last of it swept into Europe.
The resulting shock wave moved as a front with the central bulk of the material striking the Glacial Ice sheets, blasting most of the polar Ice into the Siberian area of frozen standing mammoths and mastodons covering them instantly with meters of snow and ice chunks. There is some research that shows the southern trajectory ice chunks so liberated fell in a swath of the South Eastern USA and formed the Carolina Bays as they splashed impacted, along the southern rim of the secondary ejecta pattern.
“For the large impact area with no crater, it could have been the near passing of one of the gas planets of an inbound large loose comet that was gravitationally fragmented into hundreds of thousands of smaller pieces, that impacted the earth over several hours upon arrival, starting in the SW USA/Mexico area moving North East as the earth revolved and the last of it swept into Europe.
The resulting shock wave moved as a front with the central bulk of the material striking the Glacial Ice sheets, blasting most of the polar Ice into the Siberian area of frozen standing mammoths and mastodons covering them instantly with meters of snow and ice chunks. There is some research that shows the southern trajectory ice chunks so liberated fell in a swath of the South Eastern USA and formed the Carolina Bays as they splashed impacted, along the southern rim of the secondary ejecta pattern.”
At this time no one knows if the proposed YD impact was perhaps a fragmented body with multiple impacts. Some people think so. If so, it is far too early for figuring out what multiple impacts would have done or where. It is probably premature to go in that direction, but who knows?
One of the important peripheral questions DOES have to be, “If the impact was in N America, then that could explain the extinctions in N America, but how did that make mammoths in extreme northern Siberia also go extinct?” If this all goes that far, then your conjecture is going to be one of many to answer that question.
As to the Carolina bays, yes, because of the non-hyper-velocity nature of the bays, some other process must have caused them than a full-speed body from space.
For those that don’t know, those are nearly 44,000 elliptical depressions, mostly in the SE USA, in an arc from FL to NJ. They are aligned in each region – north to south – and the alignment changes gradually, in such a way that they all seem to point to the centroid of the arc that they seem to form. They have been known about since about 1930, and NONE of the posited explanations so far has worked. Despite it failing as an explanation, the people who advocate winds claim to have the answer. This explanation has been ruled out as a FAIL on more than one occasion, but it doesn’t stop the “aeolian” people from claiming they have the answer.
As to secondary impact – of ejected materials landing far from the initial impact site – that IS being studied by some people, with me on the periphery of that. I can say that I favor that, but it is a LONG way from being accepted. (When I use the term “arc” above, I DO mean it, too. It is, in fact, a very tight arc – amazingly. Both the alignments and this arc show a centroid near the Wisconsin border with Illinois. This dual alignment is something that the aeolian folks couldn’t explain, even if they wanted to. They would only be able to invoke “coincidence” to explain it.) The aeolian people claim the high ground, but when I look at their work, I see many assumptions that are not sustainable.
Another thing about the Carolina bays is the difficulty in getting a date for them. Depending on where the dating samples came from, the dates range from about 11,000 to about 300,000. One guy I know says it is either 40,000 or 130,000. And this is in the times when we have REALLY GOOD dating techniques! C14 may or may not be useful, because it is only good up to about 55,000 years ago. But there is precious little organic material to work with. The sampling issue comes from the assortment of sampling locations. Almost all are just outside of the bay rims, but some ore ON the rims, and some under.
The bays have one more interesting feature. There is a layer of very pure quartz sand, draped over the bays. It tends to be about 1 meter thick, at the bays, but in the surrounding region the sand layer is up to about 10 meters thick. The sand is so pure that it can be scooped straight out and made into very good glass – even without any further processing. It is thinkc enough in other places that fully grown, fallen, bald cypresses are found deep inside the layer. And these cypresses are hoisted out and made into furniture – even though they are perhaps 40,000 years old. The quartz sand is perfect for OSL dating, but they keep getting WAY different ages.
So, for now, the Carolina bays are, IMHO, undated. They MAY be connected to the proposed YD impactor, but those around me are all skeptical of that. I don’t know, myself. Obviously, if they go back to 40,000 years, there is no connection.
I read this book maybe 20, 25 years ago, after finding it browsing in the local library, and for ME, the “secret” of Atlantis was pretty much a resolved question from that point forward… Not that Muck necessarily had all his science right (especially considering he wrote this book at a time not even the Big Bang theory had been “proven” over the Steady State theory of the universe), but that I DO believe he proved a small comet or meteorite hit in North America and probably bouncing into the Atlantic 10-12,000 years ago.
I JUST finished watching a new, 2-hour show on the History Channel about the origins of Clovis Man on North America and the “curiosity” about why and how both Clovis AND 80% of all large land mammals on North America suddenly VANISHED about 13,000 years ago, and then about 2,000 years later, they start seeing human artifacts again… Ice cor samples revealed that just as the ice age was retreating, allowing humans to setle North America, a second, shorter “ice age” of about 1,000 years QUICKLY descended upon the planet, and Alan West of the University of Michigan has discovered microscopic metalic balls and “microdiamonds” at the level at that EXACT point in the geologic layer ALL OVER NORTH AMERICA that indicate the distribution of materials from a comet or meteorite — materials that RARELY exist anywhere but in OUTER SPACE.
Of course he apparently never heard of Otto Muck, and he thinks his idea is ALL NEW and that said meteorite hit the ice mass in Canada, and he could be right — or they BOTH could be wrong…
It seems highly unlikely that the stories from antiquity were simply made up. more likely there were catastrophic events over large areas; and that we simply assume all were local events. how long ago they happened, passed from generation to generation, none can say with certainty. however, they were large enough to remain with us many generations later.
two events stand out. the great flood and the day/night that took too long. Perhaps we underestimate how long ago these events happened. 13,000 years is what, 650 generations?
“In the section “A Collective Amnesia” of Worlds in Collision, published in 1950, Velikovsky outlined his principal psychological thesis. His theory of collective amnesia explains the inability of people to look at the overwhelming evidence of global catastrophes — from all parts of the world — that is unequivocally there, and the unwillingness to see the implications of that evidence. Velikovsky put this as follows in Worlds in Collision:
The memory of the cataclysms was erased, not because of lack of written traditions, but because of some characteristic process that later caused entire nations, together with their literate men, to read into these traditions allegories or metaphors where actually cosmic disturbances were clearly described.”
All of these attempts to explain away impacts stem from the collective trauma buried in our racial memories. We need to feel we are important and have some control over our lives and the world, however the delusion of human control is snuffed out by the uncaring destruction that is unleashed on the world by what have been repeated impacts of celestial bodies. So, they didn’t happen, and we live in a very slowly changing world where we are important and powerful beings.
It could also be argued that the irrational fixation on anthropogenic climate change is the other side of this collective mental illness. We need to feel important and find it almost impossible to believe we are not, so, anthropogenic climate change that can destroy the planet.
““In the section “A Collective Amnesia” of Worlds in Collision, published in 1950, Velikovsky outlined his principal psychological thesis. His theory of collective amnesia explains the inability of people to look at the overwhelming evidence of global catastrophes — from all parts of the world — that is unequivocally there, and the unwillingness to see the implications of that evidence. Velikovsky put this as follows in Worlds in Collision:
The memory of the cataclysms was erased, not because of lack of written traditions, but because of some characteristic process that later caused entire nations, together with their literate men, to read into these traditions allegories or metaphors where actually cosmic disturbances were clearly described.”
All of these attempts to explain away impacts stem from the collective trauma buried in our racial memories. We need to feel we are important and have some control over our lives and the world, however the delusion of human control is snuffed out by the uncaring destruction that is unleashed on the world by what have been repeated impacts of celestial bodies. So, they didn’t happen, and we live in a very slowly changing world where we are important and powerful beings.
It could also be argued that the irrational fixation on anthropogenic climate change is the other side of this collective mental illness. We need to feel important and find it almost impossible to believe we are not, so, anthropogenic climate change that can destroy the planet.”
A good observation. And true, about the written accounts, though many were pre-writing and were kept as oral traditions until writing came into vogue. Those ancient accounts WERE very clearly describing big, bright, burning objects descending to the earth and causing havoc – quakes, huge explosion sounds, rains of fire, inundations, many or most of the people being killed.
The amnesia was willful on the parts of the first western readers of/listener to those accounts – insisting that the ancient peoples were all illiterates with minds like infants, and isn’t it a shame how they make things up?
Well, if it was one account out there in isolation, no problem – it is someone’s fantasy. When the same kinds of accounts show up in hundreds of ancient societies, scientists need to wake up and smell the commonality in the accounts.
Yes, the amnesia is there, – and it occurred in the last two centuries or so. And it has gotten in the way of us learning our own history, by replacing it with the silly transliterations of the early archaeologists.
Velikovsky did a decent job of accumulating these accounts, as well as pointing to things like the mammoths in Siberia, the erratic boulders, the bone caves – even if his astronomy was way off course. Like early archaeologists trying to prove the literal truth of the history in the Bible, Velikovsky seemed to be trying to do the same thing, about the Exodus and manna, etc. And all he did was embarrass himself – though Harlow Shapley of Harvard was an asshole in the way he dealt with it.
when it was obviously human hunting.
=========================
hunting does not explain the sudden demise of Siberian mammoths 12000 years ago, with the rapid freezing of many specimens.
Proceedings of the National Academy of Sciences PNAS
vol. 106 no. 43, Todd A. Surovell et al, 18155–18158
October, 2009
An independent evaluation of the Younger Dryas extraterrestrial impact hypothesis
Use the Data Supplement page link beneath the PNAS abstract for a PDF download providing lab procedures, sample sites details, and data table.
Ted –
Yes. This is the Surovell paper in which he failed to follow the proper methodology when taking samples, so he screwed the pooch. This work was well rebutted. Surovell hasn’t tried gathering samples again, from all appearances.
For some reason the YDB skeptics still haven’t enlisted an archaeologist who know how to take proper samples from a dig.
Steve Garcia,
Are there sources for these objections to the Surovell et al work & qualifications?
I have one somewhere from 2009 or 2010, but am finding it hard to locate. In its stead, I will provide 3 or 4 others.
Blog post with the main thing being the LeCompte paper just below here…
http://cosmictusk.com/wittke_pnas_younger_dryas_clovis_comet/
The first one LeCompte et al 2013 Evidence for deposition of 10 million tonnes of impactspherules across four continents 12,800 y ago has this:
One fully independent one, with the link broken to the article, but much of the article pasted into the post (Sept 2012):
http://cosmictusk.com/surovell-comet-asteroid-impactyounger-dryas-edward-vogel-oregon-south-carolina-topper-spherules/
Here is another blog post. With post comments by George Howard who is sometimes a co-author Unfiltered: Surovell – Holliday in PNAS, 2009:
http://cosmictusk.com/unfiltered-unsorted-surovell-holiday-et-al-in-pnas-2009/
–An earlier rebuttal to more failures to replicate–
The full paper Lecompte et al 2012 “Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis.”:
http://www.scribd.com/doc/106210252/Independent-Evaluation-of-Microspherule-Results-From-Younger-Dryas-Impact-Hypothesis
Also you might want to take a watch of the slide show presented by Malcolm LeCompte (astrophysicist at Elizabeth City State University in North Carolina)………..
— Abbreviated YDB evidence at 2011 Bern, Switzerland, INQUA Conference:
http://cosmictusk.com/swiss-bliss-2/
I think these will give you a good picture.
Thank you! Off to recharge, but will go over these carefully tomorrow.
Fascinating topics – both the Younger Dryas, and the lively debate!
People and camps can & do disagree and debate, sometimes on large demographic scales over long spans of time, without it being necessary for anyone to have “screwed the pooch”, or to not “know how to take proper samples from a dig”.
I – we – needed to see real support for denouncing the competence of Surovell – and several others, and their many coauthors – and that isn’t addressed at CosmicTusk. George Howard, Steve Garcia et al simply have other work-results, interpretations and opinions … none of which puts a dunce-cap on Surovell.
On the contrary; to all indications Surovell is the solid professional, academic career scientist that he appears to be, and so are the others who publish findings & work at odds with the proposal that a large impact initiated the Younger Dryas.
=====
I certainly have no basic personal aversion to the general idea of a big strike at 12,800 ya. I once ventilated excessively at the Carolina Bays phenomena … and am still sentimentally attached to their mystery. Reluctantly, I removed the Bays from the evidence-table.
The problem with this strike-hypothesis, is the lack of impressive, widespread, compelling evidence of it. The necessity to fuss over details of the sampling procedure, to wax pedantic on the use of the microscope and lab-techniques for sorting tiny artifacts, is inauspicious to the point of irony.
We’re talking about the virtual obliteration of our world, figurative, geologically, late last week some time’, yet the aftermath of this cataclysm is not glaringly obvious and perfectly well-known to every Junior High kid? I believe the event described would in fact leave “overwhelming” evidence, “most everywhere”, yet the evidence offered is more tentative than thundering.
I live on the Olympic Peninsula, which was the site of a major terminus lobe and spectacular transition to the Holocene. We don’t have to indulge in fine argumentation to show convincingly the evidence of events 14,000 or 11,000 years ago. They are glaringly and even hair-raisingly clear, even to young children. Tweens soon learn to spot ‘fossil’ shorelines of the extinct Lake Elwha, and labor through Olympic National Park brush, following their contours across the rugged, densely-forested hillsides. They point across the valley and correctly identify where the far shoreline of the now-gone ice-dammed montane Lake would have been.
And our part of the planet was severely smote 12,800 ya, yet we aren’t all perfectly aware of it, from ubiquitous & prominent evidence?
Nooo … we know of other events & processes at the same time, and evidence of them is sophomoric to find, assess and understand. Eg, many early-Holocene volcanoes far & wide left big & little calling-card layers in every local bog, and all the lakes. So should have a major extinction-strike in the same time-frame … yet it isn’t there, although it should be easily spotted between other datable horizons. Same story, all across the continent.
Ted –
“I – we – needed to see real support for denouncing the competence of Surovell – and several others, and their many coauthors”
You obviously did not even bother reading the papers and their “real support”. It’s called laboratory tests – empirical science.
How Surovell couldn’t even give Daulton proper samples to work with. How Surovell did sloppy science, as opposed to the volumes of testing done by Kennett et al. The lab results mean nothing. Lab results aren’t science to those who don’t want to see actual test results. And Surovell’s bad science put up against Kennett’s – Ted, there is no comparison.
Ah, but Ted, Surovell and Pinter and Daulton – they are the ones who put the dunce cap on the YD “team”. Oh, they have mocked. And EVERY time they talk to a science editor, it is with derision and disrespect – always a “Requiem” or “bury the YD impact.” Kennett et al are just trying to do the science.
And it isn’t a mattre of opinion alone, or interpretation. When nothing terrestrial can achieve 2200°C but the evidence says it got that hot, is it interpretation to say it wasn’t a volcano and wasn’t a forest fire? No, it is admitting what the physics tells you.
And then Surovell et al are quiet about that – until they have a 50-year difference they want to quibble over – and decalre the wole thing dead again – because of THEIR not wanting anyone to “interpret” anything along lines they don’t approve.
No, the interpretation b.s. is coming from the other side, while the “forensics” is done over and over and over again – to try to get past this impasse with these “skeptics, without evidence”. People in these comments ask “Well why did it last 1300 years, when no dust can stay in the atmosphere that long?” Exactly! And there is no capacity to address such questions, not yet, not when the basics are beclouded by people who can’t do science right and then take their own inadequacies and declare them superior. So Kennett et al go out and spend another year on ANOTHER “forensic” refutation of their nonsense rebuttals.
Also, don’t take comments (even by George) at CosmicTusk as more than commentary. The real work is being done by others.
“The problem with this strike-hypothesis, is the lack of impressive, widespread, compelling evidence of it. The necessity to fuss over details of the sampling procedure, to wax pedantic on the use of the microscope and lab-techniques for sorting tiny artifacts, is inauspicious to the point of irony.”
The only real “compelling evidence” of a strike that the world will certaiinly accept is a crater. Nothing short of that will convince anyone. And with it seeming to have been in a location that was under maybe half km of ice, a crater may never be found. In case you don’t know it, an impact was NOT what the Kennett et al crowd were thinking about at the beginning. It was the impact material spikes in the black layer – specifically at the BOTTOM of the black layer – that led them to it. Firestone originally was simply looking for why the C14 curves were weird at certain times. Nobody went out and said, “Let’s go out and find some evidence we can claim to have been a comet!”
If you FIND such materials, just as Luis Alvarez found the Iridium in the K-T boundary, what do you DO with it. BTW, those two layers are the only ones in the geological record, it seems, that are narrow, quite visible layers. That makes them both exceptional and significant. But that layer was an accidental discovery of the whole thing. Like I said, Firestone was just wondering why C14 levels were weird. Then other stuff started showing up as well, and all at 12.9 kya.
“You go where the evidence takes you.”
Ted: “We’re talking about the virtual obliteration of our world, figurative, geologically, late last week some time’, yet the aftermath of this cataclysm is not glaringly obvious and perfectly well-known to every Junior High kid? I believe the event described would in fact leave “overwhelming” evidence, “most everywhere”, yet the evidence offered is more tentative than thundering.”
Actually, Ted, you are wrong on this, this degree of obviousness. The biologists and climatologists have been working on the YD for a LONG time, wondering WTF???? It’s VERY obvious to them, the ones who have to deal with it professionally. They have been trying to explain it since it was first discovered. It was a VERY significant change in the flora – very noticeable. And if junior high kids were out sampling stuff one to six meters under the ground, YES, they would find it. Find the black layer and wonder about it.
The evidence is NOT tentative. The understanding of it is, but not the evidence. Those spikes are not tentative. That they all come at the same age – that is not tentative. That they are materials previously always associated with impacts – that is not tentative, either.
What you have is a group of skeptics who can’t do their own science worth a damn and THEY play little pouting games about how they don’t WANT it to mean what it means to anyone who has dealt with impacts before. They claim it doesn’t mean what it DOES mean. The Pinter people used to work on floods on the Mississippi River and such and forest fires. They have about as much expertise in this as President Obama – yet they don’t WANT it to be true, so they deny any clear presentation of the evidence, pouting all the way.
Muck’s thesis accounts for the Frozen mammoths
I liked Muck’s book. I think I had a first edition, too. But Muck totally missed it on the Carolina bays. There is zero evidence that they were comet pieces. The shallowness of them precludes hyper-velocity impacts. It doesn’t preclude much slower impacts, like from the ejecta from an impact elsewhere, but a hyper-velocity event has far too much energy to produce the bays.
And BTW, someone has done an actual count of them, using LIDAR imaging – which shows up ones that are completely invisible to the naked eye. And a LOT of them are invisible like that. They total 43,900. Some people believe there are as many as 500,000, which seems reasonable, but it is only 43,900.
DirkH – 8.2kya is not when Plato dated Atlantis. Plato was about 520BC, Atlantis, by his account, 9000 years earlier = 11.5kya just around the Younger Dryas warming, more or less.
Platos account would be consistant with a neolithic civilization on the shores of the Med. being inudated by the YD warming.
Plato’s account is easily understood by dividing everything by 10, the years, the size of the city walls, etc, which shows that Atlantis was Thera and the destruction was that of the Minoan culture by the Theran volcano. Remembering that 900 years before Plato, the “Pillars of Hercules” referred to the Sicilian pass (later called “Scylla and Charbides”). The Egyptian accounting which Plato recorded in “Timaeus” used units which interchanged by 10.
It’s rather funny the way everybody assumes that Plato meant this when he said that, and all on different aspects of his tale. It’s created an industry – “Let’s second-guess Plato!” Some do it on location, some on dating. Like Plato, perhaps the most educated man of his time, didn’t know where the Pillars of Hercules were. And like he didn’t know how to count.
What caused the 11 degree warming in 100 years at the end of the Younger Dryas?
Doc –
That is one of the $64,000 Questions. I am the only one who has even tried to answer that, that I know of. But don’t take that 100 years at face value. No matter what chart you see, the only source we have for temps and timing is GISP2 and other ice cores – and they are LOW res proxies, as are all ice cores. Even TWO hundred years s too high res for them – they can’t really do that. It’s the nature of the bubble migrating a little up or down within the core. Kind of like fuzzy vision. So if you see a ONE hundred year number, you can look at it a s guess.
Not only that, when you see those steep slopes, they have a straight line between the two points. But the actual line might go straight down from the upper point and maybe even go past the lower one and come back up to it. So that slope is shown at its MINIMUM slope. That 100 years may be 100 days or 100 hours coming up from the lower temp to the upper one.
In fact, the latest I read on that one was that it was less than a year – and a shorter time even than the drop INTO the YD. Based on what? They start with the one graph, maybe this one, and then maybe find with some other proxy that there should be another point – or maybe the one had a point straight up from the lower one. OR NOT. Who KNOWS?…LOL
But the short time coming out of the YD seems to have quite a bit of support. If someone knows they haven’t told anybody I know. And the people I know would say if THEY knew.
I reckon it was the completion of the melting of what had been a solid Arctic ice cap which started out at miles thick.
The sudden end of the Younger Dryas is not unique or mysterious, within the broader Pleistocene, which shows a continuous record of sudden cooling followed by sudden warming, ‘on all time-scales’.
Events like the Younger Dryas decorate the history of the Ice Ages. That any one of them starts with suspicious suddenness, and/or ends strangely-abruptly, in neither suspicious nor strange, within the overall climatic regime of the Pleistocene.
Looking at the Ice Ages overall, there is no call for any ‘special dispensation’ on the Younger Dryas. Either to start or end it.
Explain the Younger Dryas, and we explain the Ice Age.
“The sudden end of the Younger Dryas is not unique or mysterious, within the broader Pleistocene, which shows a continuous record of sudden cooling followed by sudden warming, ‘on all time-scales’.
Events like the Younger Dryas decorate the history of the Ice Ages. That any one of them starts with suspicious suddenness, and/or ends strangely-abruptly, in neither suspicious nor strange, within the overall climatic regime of the Pleistocene.
Looking at the Ice Ages overall, there is no call for any ‘special dispensation’ on the Younger Dryas. Either to start or end it.
Explain the Younger Dryas, and we explain the Ice Age.”
You can deny it all you want. People are coming around. See this NatGeo article with eminent Wallace Broeker (the oceanic conveyor) prominently included:
http://news.nationalgeographic.com/news/2013/09/130910-comet-impact-mammoths-climate-younger-dryas-quebec-science/
BTW, PNAS is a journal that the Pinter side has used themselves in the debate.
Steve Garcia:
Little wonder that Wallace Broeker is attracted to the well-falsified YDIH, since he believes that humans caused the natural slight warming from 1977 to 1996, & are still warming a cooling world.
Anyone who has managed to convince himself that the Modern WP needs a special explanation, while the LIA, Medieval WP, Dark Ages Cool Period, Roman WP, Greek DA CP, Minoan WP, Holocene Climatic Optimum & 8.2 Ka cooling event don’t, would naturally be attracted by special pleading for the totally natural & terrestrial YD.
Actually, Broeker is getting smarter in his old age. He has abandoned the Lake Agassiz flood, for example, because the recognized that the ice front had not receded enough and that that drainage path was not open in time.
In addition, the scouring that would have occurred – there was no evidence whatsoever, anywhere near the southern end of Lake Agassiz.
That has not prevented others from pushing the same issue, with the outwash going UP NORTH along the Mackenzie River and out into the Arctic Ocean near Alaska. HOW they could think that an outpouring of fresh water into the western Arctic is going to magically stay fresh all the way to the N Atlantic east of Iceland and only THEN sink, it buggers the imagination. I see it as being retarded, myself.
But I have not seen that Broekers is part of that.
I had the same attitude toward Broeker as you do. When he backed off the Lake Agassiz ice dam breakup, I was impressed.
Meant Broecker. Sorry. Followed Steve’s misspelling.
Proceedings of the National Academy of Sciences PNAS
vol. 109 no. 19, Jeffrey S. Pigati et al, 7208–7212
April, 2012
Accumulation of impact markers in desert wetlands and implications for the Younger Dryas impact hypothesis
A Data Supplement page is linked beneath the PNAS abstract for a PDF of methology & data.
Fine point, Ted, I remembered seeing that but could not think where to find it. About the impact event, as Laplace said, “there is no need for that hypothesis”, and Occam’s razor says throw it out.
I think it probably hit the ice sheet, that is why there is not evidence of a crater in the crust. The ice took the hit. melted water ran into the gulf stream, and across the continent.
iron brian
Re the very rapid warming, watch the video posted above by Robert Schoch.
http://www.robertschoch.com/plasma.html
Solar storm.
Dont forget the eruption of mount Toba induced a thousand year cooling.
Archeology in Bahamian Blue Holes has revealed massive African dust storms inundating the islands then. This would be in agreement with massive American fire storms, drawing air and dust from Africa.
The Toba and 1,000 year assertion is interesting. May I ask where you got that? If Toba’s effect lasted 1,000 years that would mean the YD lasting 1,000 years is not impossible.
I will be looking into that myself, but if you have a source it could help.
The effect of Toba did not last 1000 years. Its effect on weather, not climate, might have lasted six years. Lane, below, finds a mild (1.5 degree C) effect for 20 to 30 years, which would get it into the climatic range.
In any case, Toba occurred while earth was already well into its cooling process during a major glacial phase, not coming out of one & previously warming, as with the YD.
And its eruption would have produced far more powerful gas & particle effects than the hypothesized but essentailly evidence-free comet impact.
http://www.newscientist.com/article/dn23458-supervolcano-eruptions-may-not-be-so-deadly-after-all.html#.VAIi3aNupmc
http://www.sciencedirect.com/science/article/pii/S0277379101001548
Yep, and 1.3 km Fragment G of Shoemaker-Levy 9 had a plume bigger than the planet Earth – in the gravity of Jupiter. The gravity of Jupiter is about 2.5 times that of Earth.
So, how little of a plume do you think a 1.3 km impact on Earth would be? And that is not to even mention the after effects. And not to mention the smoke from the nearly continent-wide firestorm – of which the black layer is clear evidence.
Yep, the black layer being all the way over in Belgium is to be completely ignored. And Syria.
It was just your everyday garden variety brush fire. It didn’t mean anything, and it didn’t have any effects anywhere.
Book your seats.
ANALYZING A COMET IMPACT AND ITS EFFECTS USING GOOGLE MAPS AND GOOGLE EARTH
https://gsa.confex.com/gsa/2014AM/webprogram/Paper241481.html
I think alot of the megafauna drowned when all that ice was melting at its most rapid rate. They got stuck on islands that flooded, they died trying to ford across the massive rivers that all flowed south at the time.
At certain times during the ice sheet collapse lasting more 1,000 years, no animal was getting across the Mississippi river for example unless it had a canoe. The North American continent was isolated into three parts, the ice-sheet north, the west and east.
It only takes a small change in survival rates, or the number of surviving herds to make a megafauna species become susceptible to extinction.
The Bolling-Allerod (Northern hemisphere warming at 14,600 yrs ago) and Younger Dryas (subsequent 1000 yr cold interval) were parts of the last deglaciation which were driven by oceanographic processes. There is no need for an atmospheric deus ex machina. Over the deglaciation starting as early as 22yrs ago the general picture is steady changes in Antarctica contrasting with unstable fluctuations in the NH driven by the Atlantic Meridional Overturning Circulation (AMOC). The root cause of this is an instability in the AMOC arising from a positive feedback which it possesses.
Cold water formation and downwelling in the Norwegian sea drives the gulf stream – reactive flow of Carribean warm and – critically – saline water across the Atlantic to north west Europe. This gulf stream water has high salinity, and this makes the cold water formed in the Norwegian sea even more dense than would result from its temperature alone. So this cold and saline water sinks all the way to the Atlantic floor and is one of the principal drivers of the global thermo haline circulation (THC). Now more of this “deep water formation” at the Norwegian sea actually speeds up the gulf stream – something has to replace all that sinking cold super-salty water so this is supplied by the gulf stream. Thus the positive feedback – more gulf stream leads to more cold supersaline Norwegian sea downwelling leading to more gulf stream etc.. Where you have a positive feedback in the system you have the conditions for nonlinear oscillation. This is directly analogous to the ENSO in the Pacific, the positive feedback of the Bjerknes mechanism (cold upwelling strengthens trade winds strengthening cole upwelling etc.) giving rise to the ENSO nonlinear oscillator, although the AMOC operates over much longer – century and millenial – timescales than ENSO (decadal).
So a basic oceanographic feature comparing the NH with the SH in the palaeo record is more fluctuation and instability in the NH and more stable, gradual changes in the SH. The nonlinear instability of the AMOC is the root of this. Also, there is a clear signature of interhemispheric bipolar seesawing, whereby when the NH moves in one direction, the SH moves in another. This is not universal however – sometimes at the moments of biggest transition, NH and SH move together.
About 22 kYa (thousand years ago) Antarctica started warming. The NH at the same time slightly cooled. However at about 14 kYa the “Bolling-Allerod” (BA) happened, i.e. the NH abruptly warmed, as evidenced by Greenland cores. This caused a reciprocal pause and slight reversal in the (already long established) gradual Antarctic warming – the bipolar seesaw again. At the time of the BA there was a sharp rise in global sea level – 20 meters in 500 years. Weaver et al 2003 (link below) show that this was caused by a collapse of the gradually warming Antarctic ice sheet. The pulse of fresh meltwater from Antarctica had the effect of speeding up the AMOC and the gulf stream in the NH, bringing rapid warming to the NH and the BA.
The bipolar seesaw continued – as the NH became sharply warmer, there followed in the SH the “Antrctic reversal” where temperatures went slightly into decline. However down in the deep ocean, interactions between cold bottom water formed in the Antarctic and Arctic caused – about a thousand years later – an abrupt stoppage of the AMOC and the gulf stream. In fact the cuplrit was Antarctic Intermediate water (AAIW) – see again Weaver et al. With the interruption of the gulf stream the NH went cold again – the Younger Dryas. In response – by now you get the picture – the Antarctic turned to gradual warming. After about 1000 years of NH cold with no gulf stream, the effect of the Antarctic collapse subsided allowing the AMOC and the gulf stream to resume. Now followed an exception to the bipolar seesaw – both NH and SH warmed together, around 12 kYa. This marked the final end of the last glacial and the Beginning of the Holocene.
http://rockbox.rutgers.edu/~jdwright/GlobalChange/Weaveretal_Science_2007.pdf
http://epic.awi.de/15280/1/Lam2004a.pdf
The scariest thing about the graph is: That the Earth’s temperature maybe many, many degrees cooler on average than we’ve experience over the last 20,000 years?
Yes. For most of the last 2.5 million years it has been MUCH cooler. And as recently as 11,500 years ago. The end of the Last Glacial Maximum was at about 18,000 years ago.
Dust from an impact event could have initiated rapid melting by decreasing albedo of the icecap. Even if the dust fall lasted only a short time the decreased albedo would be effective long-term, resulting in the rapid melting and meltwater discharge discussed above, extending for hundreds of years. An impact event (or volcanism) could definitely be a part of this picture. It’s dangerous to attribute these rare events to a single cause when a confluence of factors may be (and probably are) at work. Also, the marked temperature decrease indicated in the ice cores could be an artifact caused by repeated fractionation of O16 away from O18, first by freezing of the glaciers, then by evaporation over the meltwater pool, followed by precipitation onto Greenland.
http://judithcurry.com/2014/06/04/explaining-abrupt-climate-change/#comment-583781
The trouble with dust-driven melting is that once a thin layer of new snow falls on the dust, it ceases to cause melting. Buried dust has zero effect on albedo.
Glaciers and icefields commonly contain many dark layers, buried beneath recurring new snowfall. The amount of plant-pollen alone that becomes visible on ice & snow over the course of each summer, can be downright startling.
Melting is indeed driven by dust, but fresh dust has to be laid down each spring, after the winter snowfall stops. Either that, or snowfall in the cold season has to cease.
You can see the effect of tire dust every spring. While precipitation exceeds melting, the dust is indeed buried, but when melting exceeds precipitation the dust layers collect and the snow along side the road melts much more rapidly than elsewhere. That is the effect I am talking about. When insolation is reduced below a certain point and precipitation exceeds melting, the albedo effect accelerates the advance of glaciers. When insolation favors melting over precipitation, a “tipping point” of sorts, than buried dust will be exposed at the surface and a reverse albedo effect will accelerate melting. It is often said that the Milankovitch effect is inadequate to produce the glacial cycles. With the albedo effect working to advance glaciation and the dust accumulation effect working to destroy them, there are powerful amplifying forces at work.
Comets are thought to bring bad luck. What is the origin of this superstition?
A large comet impact in the ocean could throw thousands, perhaps millions of cubic miles of water high into the stratosphere. Much of this would fall back to earth as ice.
Good question. In many, many ancient peoples there are accounts of burning objects or “stars” or “suns” blazing down and causing great noise and quakes and fires. These objects didn’t just appear in the sky one day – they were seen on their way here, as what we call comets, and the archaeologists have normally transliterated as “gods”.
Any connection with “not having a good day”?
As to an oceanic impact, we don’t WANT one of those. Hills and Goda tried to calculate the size of tsunami from stony or iron meteors impacting the ocean. The worst case – at 1500 km away – was about 2 km of run-up from the tsunami. I don’t have the source in front of me, but can find it if you’d like.
Something about that dispersal pattern that bothers me. It almost seems backwards. In other words, imagine the winds in the Northern Hemisphere were backwards from what they are today and then look at the pattern. It would look like an impact around Turkey somewhere then dispersed these things across the rest of the Northern Hemisphere. The shape of the pattern given almost defies physics with winds going mainly west to east. One would expect to see relatively little material to the west of the impact site with the amount of debris fanning out as it is dispersed by winds to the east.
Also, there are a large number of places where such an impact could have occurred but have been completely erased by natural forces. For example, much of what is now under water in the Gulf of Mexico was dry land at that time as the glaciers had not yet melted enough to raise sea levels enough yet. Sea levels would have been about 200-ish feet lower than today so everything that is currently under about 200 feet of water would have been land.
The Mississippi River would have transported an absolutely incredible amount of sediment from glacial till and loess. You think it is muddy now? When the glaciers were retreating it must have been extremely thick with extremely fine silt.
One way to find the location of impact might be to sort the debris by weight assuming that the heavier samples settled out of the atmosphere closest to the event.
It is possible you are misunderstanding that dispersal map.
1. The area in N America is not where the wind was taking the dust. That was the area that was burning.
2. Those only happen to be the areas SO FAR where they’ve found the black layer.
3. In addition (my guess here) the Heinrich events (of which the YD onset is considered H0) are universally interpreted as “ice rafted debris”. The evidence for the Heinrich events is layers on the N Atlantic, layers of dust. (I originally thought it was talking about full-sized rocks, but then found out it was dust. Given the timing of H0 at the same time as the YD onset, which is the same time as the BOTTOM of the black layer on land, and since the dust reached across to Belgium and to Syria , it seem logical to assume that the dust also fell onto the N Atlantic and sank. If this happened at the same time as H0, then the dust should either be mixed with the H0 dust – or it could BE the H0 dust. It might be an interesting thing to do – to compare, or to see if these same materials are in the Heinrich dust. It is certainly a falsifiable hypothesis, and falsifiable conjectures are what solid science is built on. Of course, if found to be true, this would definitely have repercussions about all the other spikes in the ice cores and the other layers of Heinrich dust.
So there was no new snowfall for hundreds of years that coated the ash and dust with immaculate white stuff.
Other glacial-interglacial transitions during the Pleistocene show the same pattern as the onset of the Holocene.
The YD & the rapid 8.2 Ka cooling are nothing unusual during deglaciations. In fact, they’re similar to Heinrich Events during glacial phases, the periodic armadas of icebergs launched into the North Atlantic from the Canadian, Greenland, British & Scandinavian Ice Sheets.
I agree – its about ocean circulation driven bipolar seesawing plus the effect of freshwater pulses from ice cap collapse during deglaciation. See my post 8 posts upstream.
At the same time, you should understand that nobody knows the causes of those other “nothing unusuals” during deglaciation. But you should also include the D-O events BEFORE the deglaciation.
Saying that they are there in the ice cores is one thing. Saying that these two are explained because of the existence of the others – which are unexplained – doesn’t answer anything.
As to the Heinrich events, the YD onset is pretty much accepted as Heinrich event H0. The YD caused dust to fall across the Atlantic. Heinrich events are interpreted as due to “ice rafted debris” – DUST – in the N Atlantic sediments, one of which, H0, coincides with the YD onset. Both are about dust. Could there possibly be a connection? Even if it isn’t accepted as such, if both happened at the same time then there should be YD onset dust mixed in with H0 dust. And that could mean what? Among other things, the idea that the H0 dust is ice rafted debris may need reinterpreting. (DO NOT take this as part of Kennett et al and their YD research; this is just my own thinking.)
Heinrich Event ice rafted debris is not “dust”. It’s referred to as gravel, ie greater than 2mm in diameter, although the sediments might contain “sand” as well.
http://scholar.google.com/scholar_url?hl=en&q=http://epic.awi.de/28213/1/Polarforsch1987_3_1.pdf&sa=X&scisig=AAGBfm1A3-qZBjBZCznvm7JKNTUCvy_Nyg&oi=scholarr
There are good physical climatological explanations for D/O events during glacial phases & Bond Cycles during interglacials. No special explanation is needed for the YD, any more than for the Medieval & Modern Warm Periods or Little Ice Age.
“Other glacial-interglacial transitions during the Pleistocene show the same pattern as the onset of the Holocene.
The YD & the rapid 8.2 Ka cooling are nothing unusual during deglaciations. In fact, they’re similar to Heinrich Events during glacial phases, the periodic armadas of icebergs launched into the North Atlantic from the Canadian, Greenland, British & Scandinavian Ice Sheets.”
No. You are only going by the ice cores. These are not just things that show up on that curve.
The YD IS a very unusual and unique period in the Pleistocene. It was first noticed by climate scientists and biologists, and tehy have tried to identify its causes for a very long time.
The 8.2kya is not just about cooling. It is about the impact it had on forest fires, vegetation response, sea levels, etc.
BOTH of these periods have a long way to go before we fully understand what happened. It isn’t just pointing at a graph and noting that there was a blip.
Similar to Heinrich events? Do we really know what caused Heinrich events? They say “ice rafted debris.” And where did that come from? It was dust settling to the bottom of the N Atlantic – at the same time the (proposed impactor caused) continent-wide conflagration in N America was sending smoke and dust across to Belgium and Syria. If both happened at the same time, then there should be N American continental dust in the Heinrich dust.
And that is exactly what is there.
But they looked around for a mechanism within Gradualism and decided it was icebergs.
“nanodiamonds, the production of which can be explained only by cosmic impact..”
I suppose it is redundant to say the diamonds are made from plants and animals – a kind of grisly observation to comtemplate – this is real climate change impact!
Steve Garcia
August 29, 2014 at 1:50 pm
“none of their “requiem” team was an archaeologist, with experience taking careful samples from the side of a pit.”
Geologists probably taught archeologists this skill. Indeed for a job like this, I’d go with the geologist/paleontologist.
Not so. Archaeologists have to get more precise samples. One inch can be 500 years. For geologists, what do they care about 500 years? For archaeologists 500 years is twice the life of the USA.
Suffice to say for now that this premise has been on the table for a long time. I even wrote a book on the event in 2009 “Sudden Cold” An Examination off the Younger Dryas Interval. Also Steve Garcia is correct when he states there were other lesser impacts likely at about 4200 BP and 8200 BP., and too at 3600 BP, 500 A.D. and 1500 AD. I also think that in addition to the map of YD coverage that Africa was also affected by the 12800 BP, as many animals became extinct there also. I am just in the process of writing a book on the Ice Age mammal extinction as well. Thank-you Rod Chilton, http://www.bcclimate.com
Hey, Rod. For those who don’t know, Rod is an actual climatologist.