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.
Bill Illis
August 29, 2014 at 10:06 am
The same D/O Cycles & Heinrich Events are evident in previous glaciations & transitions to interglacials, along with Bond Cycles within the interglacials.
If there were an impact around the time of the YD (which I doubt on the flimsy basis of the evidence), there’s no reason to imagine that the putative event caused the YD.
Does only Kennett’s team find support for their hypothesis? Is no one else looking?
None of the other rapid changes in the D-O, the Heinrich events, nor the Bond events are coincident with a black layer with the nanodiamonds and other impact markers. (The only other layer with any similarities is the K-T boundary. And we know what that one did (we think).
The black layer shows up across N America from Alberta to the Carolinas and down to Blackwater Draw and other places, as well as in BELGIUM, and SYRIA, and in S America at the northern end of the Andes.
Like it says above, the black layer is found in an area that spans some 50 million square kms, so it was not small. It was not even medium nor Goldilocks-sized. This was the mother of all firestorms on one of the three biggest continents. And it reached across the Atlantic AND the Mediterranean, as well as the Gulf of Mexico and Caribbean. Obviously it sent monumental amounts of soot and smoke into the air, which if it laid down a layer in Syria stronly suggests that the smoke went around the world. We are talking of a smoke cloud that was
. That the impact “forensics” lie at the very bottom of that black layer at its interface with the next lower soils, indicates that the impact markers and the black layer occurred together. And that the black layer was added to, to make a thickness that averages about 10 cm (4″).
50 million km^2 is basically 10% of the Earth’s surface. That is far bigger than any natural event in the known history of mankind.
Greg sez: “Tom, this is basically climatology. Expect outrageous and unwarranted claims of certainty.”
Not at all. Multiple samples of the relevant strata–no magic single tree in Yamal. No tree rings, speleothems, or bat guano strata. No ad hominem arguments. No use of the terms “robust,” “consistent with,” “rigorous,” “transparent,” “open,” or “peer reviewed.” As near as I can tell, sufficient methodology is included to permit replication. But most of all, there is no de rigueur shibboleth/ecco la fica in the closing paragraphs stating that this study confirms CO2 as the source of all global warming.
Yes, it seems the unwarranted uncertainty was some editorial enthusiasm at WUWT. “Younger Dryas climate event solved via nanodiamonds – it was a planetary impact event”
Neither the press release nor the quotations from Kennet are making such claims. He always seems clear that it’s their hypothesis, not that it’s “solved”.
My criticism was misplaced.
Hahaha – “As near as I can tell, sufficient methodology is included to permit replication.” Yet the skeptics of this couldn’t follow simple protocols and screwed up their effort at replication – and then they ran with their bogus results, bad-mouthing the YDB scientists.
Am I the only one here who thinks some scientists got their degrees out of Cracker Jacks boxes?
ROFL – I didn’t think so. 🙂
Jimbo
August 29, 2014 at 10:13 am
CO2 over 400 ppm in the late Allerød. Who knew that there were so many SUVs at the end of the Paleolithic?
Germany had about 10,000 CO2 samplings in the early 1900s (up into the 1930s). It didn’t affect jack. Their weather was as crappy as it often is. And lest anyone thinks “Oh, what did they know way back then?” the sampling of CO2 was well refined by about 1850. Or so I’ve read.
Not an expert but 13,000 years is like geologic yesterday. Point me to the crater, please?
The Laurentide Ice Sheet was over 3km thick in places. Depending on the impact site, angle, energy etc. there may not have been a significant amount of crustal damage done and the melt alone could have erased it. There could have been no crustal damage done if it hit a thick area of ice. A bunch of unknowns here as the nanodiamonds would require the impactor be one of the more carbon rich meteorite types if terrestrial carbon was not the original source. Not enough data here to make that call but a missing impact site is not a falsification criteria here.
Peter Schultz did hyper velocity impacts experiments at NASA Ames. He got speeds of like 4 km/sec or so, and used super high-speed cameras. You are right – hitting dead center on about a 1 inch slab of ice. The loose sand underneath was still flat and basically unmarked. The ice? All OVER the place. It’s on a NOVA episode about the YD impact from about 5 years ago. One interesting aspect is that the highest velocity of ice was straight up, even with a 45° impact.
My best info is that the thickest ice at the Last Glacial Maximum was 2 km thick at its center – near the eastern edge of Hudson Bay. I assume that it tapered to the edges. But I have no idea how high at the edges. I don’t think anyone does. But certainly less than 2 km. If the calving ice at the edge of the Antarctic is any guide, the edge was maybe 100-200 meters, and maybe tapered sharply up to 500-1000 meters. (My guess.)
The hypothesis has the impact in the Great Lakes area. One guy – MIchael Davias – thinks that it was Saginaw Bay. And that the impactor was so big it made it THROUGH the ice sheet there and carved out the bay. With the ice being ejected along with bedrock, the rock probably ended up on the ice sheet not so far away. His idea has a lot of merit, but most scientists pretty much ignore it. After all, he’s talking about a catastrophe.
There’s no catastrophes in Gradualism!
It’s in the Southern Ocean, southeast of Madagascar. Open Google Maps (satellite view) or Google Earth.
I believe that was Shiva – an entirely different time and a really big one in its own right. The tsunami must have been prodigious.
Or maybe Mesolithic. More advanced than the Paleolithic, but still, how did they produce so much CO2? They hunted in the forests. They didn’t burn them down.
why just let them collaborated ‘mastodons’ stay away and talk ’bout
SCIENCE.
Asking. Hans
That is not the explanation because many events similar to the Younger Dryas have happened through out the historical climatic record as Don Easterbrook so clearly shows.
If this was a one time isolated occurrence the theory they advance might of had some merit but the Younger Dryas event is not an isolated unique climatic event when one reviews the data.
My question is why is it only in climate science that data is some how ignored?
A much better explanation is these abrupt climate changes had to do with sea ice dynamics when the initial state of the climate was not to far from boarder line threshold values for glacial versus non glacial conditions moderated by solar variability and all the associated primary and secondary effects.
Don Easterbrook says:
August 21, 2014 at 8:41 am
A big problem with computer models is that the results depend not only on what assumptions you put into the model, but also what you don’t put in.
Some major problems with this particular model include:
1. “The rapid climate changes known in the scientific world as Dansgaard-Oeschger events were limited to a period of time from 110,000 to 23,000 years before present. The abrupt climate changes did not take place at the extreme low sea levels, corresponding to the time of maximum glaciation 20,000 years ago, nor at high sea levels such as those prevailing today – they occurred during periods of intermediate ice volume and intermediate sea levels.”
This statement is dead wrong–both the oxygen isotope ratios and temperature curves from the GISP2 ice core show that the most sudden warming that brought the last Ice Age to a close occurred abruptly 15,000 years ago when ice sheets were at their maximum extent and sea level was at its lowest. The ice sheets had been at their late glacial maximums for several thousand years when, out of the blue, temperatures suddenly soared 13 C (23 F) in something like 100 years, causing wholesale melting of the ice sheets. Then, just as abruptly, temperatures turned around and cooled 10 C (18 F) by 14,000 years ago. Temperatures then fluctuated up and down( but not so intensely) at intermediate levels for about 1,000 years. 12,700 years ago, temperatures took another nosedive into the Younger Dryas cold period and remained at full glacial conditions for 1,000 years. During the Younger Dryas, temperatures repeatedly changed abruptly from cool to warm (the Dansgard-Oeschger events). 11,500 years ago, another great warming spike caused temperatures to soar 12 C (21 F) in about 100 years (at one point, around 20 degrees in 40 years), then continued warming at slower rates for a total warming of 17 C (30 F) from 11,700 to 10,000 years ago. (Keep in mind that these temperatures are for Greenland, not global, but they correlate very well with temperature conditions in the rest of the world). These abrupt, multiple, intense changes (back and forth) at full glacial conditions (not ‘intermediate’) hardly sound like changes caused by gradual changes in ocean/atmospheric conditions.
2. All of the five most significant colder temperature changes that occurred during the past 500 years (the Little Ice Age) coincided with low sunspot intervals, lower total solar irradiance, lower solar magnetic flux, and increases in the production rates of beryllium-10 and carbon-14 (isotopes created in the upper atmosphere by increase in cosmic ray flux rates). These are not mere coincidences–such good correlation is not random chance, but must be due to cause-and-effect circumstances. None of this, of course, made it into the computer model simulations.
There are other serious problems with the methodology in this paper, but the bottom line is that (1) their initial premise of changes occurring only during ‘intermediate’ glacial conditions is dead wrong, and (2) sunspot intervals, lower total solar irradiance, lower solar magnetic flux, and increases in the production rates of beryllium-10 and carbon-14 argue strongly for other factors not included in their models. Thus, their conclusions cannot be considered
“This statement is dead wrong–both the oxygen isotope ratios and temperature curves from the GISP2 ice core show that the most sudden warming that brought the last Ice Age to a close occurred abruptly 15,000 years ago when ice sheets were at their maximum extent and sea level was at its lowest.”
The standard model says that the Last Glacial maximum was between 22kya and 18kya, and that from 18kya to 12.8kya was the Allerod interstadial, when the ice sheets retreated. There is nothing about 15kya except it is in the middle of the Allerod. Nothing I’ve ever seen says the ice was at maximum at 15kya. And I’ve read scores upon scores of papers on this era. Glacial Max was at 18kya. THAT was when the big melt-off was.
The D-O events were spaced at an average of 1470-1500 years. You say that they happened repeatedly during the 1300-year-long Younger Dryas. That does not compute.
I agree that the abruptness and the magnitude of temperature changes are incredibly unlikely from internal forcings. For internal forcings, only when processes self-organize, like with the ENSO, can they cause changes, but the changes only amount to a few tenths of a degree C. Extrapolating 13°C or 10°C or more out of internal forcings is asking micro-forcings to do what need super macro forcings. So, yeah, you are thinking rationally there.
But I am befuddled as to where you got your dates.
I think there is a connection between D-O events, Bond events, and the YF onset. Some say that the D-O events prove that the YD was not an impact. But the “8.2 kya event” (google it) is considered both a Bond event and a probable impact, too (depending on who you ask). If one, maybe no connection. If TWO, then one has to think about it – what would THAT tell us?
http://youtu.be/kqDewaTvwfo
http://www.robertschoch.com/plasma.html
When I read this 3 years ago I found it interesting
“Candle flames contain millions of nanodiamonds”
http://phys.org/news/2011-08-candle-flames-millions-tiny-diamonds.html
Just food for thought.
Dude, not all nanodiamonds are equal. Cubic ones are in fires. Hex ones are the ones that come from off Earth. It has to do with pressures and temps.
Presumed hexagonal nanodiamonds aren’t, as this & other studies linked here show:
http://www.scribd.com/doc/201546452/Quantifying-the-distribution-of-nanodiamonds-in-pre-Younger-Dryas-to-recent-age-deposits-along-Bull-Creek-Oklahoma-Panhandle-USA
The arrow identifying the Little Ice Age is misplaced on the graph.
So is the Medieval Warming Period.
This appears to be a rerun of several earlier articles making the same claim–a cosmic impact caused the Younger Dryas. Four of these have appeared on WUWT (some with comments from me) at the dates listed below: You can read the articles in the WUWT archives by searching for ‘cosmic Younger Dryas.’
May 21, 2013 — (my comment) There are several compelling lines of evidence showing that the Younger Dryas (YD) was NOT caused by a cosmic impact or other single event. Aside from the fact that cosmic material in YD sediments doesn’t prove a cause-and-effect relationship (correlation isn’t proof of causation), the YD lasted for about 1,300 years, which is far too long for atmospheric dust not to have fallen to the ground. Even more compelling evidence is that the YD is not a simple, single climatic event–it was a series of repeated oscillations of climate each lasting several hundred years. In Scotland, Washington state, and various other places, glaciers advanced and retreated not only during the YD, but also during the preceding late Allerod cold period. The glaciers advanced and retreated as many as 8-12 times during Allerod/YD period and is thus not explainable by a single cosmic event. There were also a number of similar glacial oscillations during the preceding several thousand years. A cosmic event cannot explain the long duration (1,300 years) of the YD nor the multiple oscillations.
June 13, 2012 — (my comment) Before jumping on the comet bandwagon, a number of dots need to be connected and some critical questions need to be addressed. For example, how could a single event, even with multiple projectiles, cause an ice age that lasted for more than 1,000 years? Surely not from atmospheric dust and if not that, then what? The Younger Dryas is not the only climatic event during the post glacial maximum period—there are also a number of others spanning the time from 14,500 radiocarbon years (about 17,500 calendar years) to 10,000 14C years (about 11,500 calendar years). These are well known, well dated, and well documented in ice cores and in the global glacial record. So the question is, how could an impact event cause both multiple warming and cooling events over a 3,000 year period? Doesn’t seem logical at all for either impact or volcanic events.
Some other questions pertain to the evidence for the proposed cosmic event. Geologists are used to studying micro-images of rocks and looking at the two samples shown in the paper, it is obvious that both show definite flow structures that closely resemble glass flows from volcanic lava. The statement “Morphological and geochemical evidence of the melt-glass confirms that the material is not cosmic, volcanic, or of human-made origin. “The very high temperature melt-glass appears identical to that produced in known cosmic impact events such as Meteor Crater in Arizona, and the Australasian tektite field,” is very vague. What morphological and geochemical evidence? As for these specimens being identical to trinitite from atomic blasts, there is surely no flow structure in the photos shown so how can they be identical?
The bottom line here is—a lot more dots need to be connected and these critical questions (as well as a number of others) need to be addressed before concluding that the Younger Dryas was caused by a cosmic impact.
March 12, 2012 –(my comment) Before jumping on this bandwagon, consider the following:
1. There may well have been a meteorite impact near the beginning of the Younger Dryas (YD), but that doesn’t prove it was the CAUSE of the YDs. It’s the same logic as saying the cause of the 1978-1998 warming coincided with rise in CO2 so the cause must be CO2. Bad logic.
2. The YD is just the most prominent of many Dansgard-Oerscher abrupt climatic events.
3. The YD ended just as abruptly as it began a little over 1000 years later.
4. The YD corresponds with changes in 10Be and 14C production rates, suggesting changes in incoming radiation and pointing toward a Svensmark type cause.
5. The problem with single event causes (e.g., volcanic eruption) is that they cannot be sustained for the length of time of the climate change. If the idea is that the cooling was caused by ejection of dust into the atmosphere, that wouldn’t last for more than 1000 years.
6. If the YD was caused by dust in the atmosphere, it should show up in the Greenland ice cores (where even very small, annual accumulations of dust from summer ablation are well preserved). There is no such evidence of dust from an impact event throughout any of the well preserved YD ice core record.
7. The list goes on and on–too many to include them all here. Perhaps a longer response later. The bottom line is that a single event, meteorite impact event doesn’t prove the origin of the YD.
I also wrote two articles explaining the issues (posted on WUWT).
http://wattsupwiththat.com/2013/06/02/multiple-intense-abrupt-late-pleisitocene-warming-and-cooling-implications-for-understanding-the-cause-of-global-climate-change/
http://wattsupwiththat.com/2012/06/19/the-intriguing-problem-of-the-younger-dryaswhat-does-it-mean-and-what-caused-it/
The issues are clear cut and spelled out in these comments and articles. In a nutshell, the Younger Dryas includes so many very sudden, intense climate changes over a period of several thousand years that it couldn’t be related to a single cosmic event. Even if there was a cosmic event as the authors postulate, it certainly didn’t cause the Younger Dryas.
Exactly. The question should be what made the temperatures rise so suddenly 14,500 BP (nr 1) and 11,900 BP (nr 7). It are these two moments in time responsible for the abundance of these tiny diamonds.
http://www.robertschoch.com/plasma.html
http://www.squatterman.com/
Dr. Easterbrook,
You are trying to to take a scalpel to a gun fight! Trying to replace the “CO2” meme with the knowledge of “it’s the sun stupid” will take many more years. Remember the movies where the witch doctor points to an eclipse of the sun and everyone starts to dance and sing to the gods? IMHO this is currently how the “deniers” are being depicted.
My prediction is that it will take another 15 more years for the “climate science” departments and many others to be condensed and or elimated. This will only happen after the “old” scientists die or retire and when the newer scientists can publish without the obligatory bow to CO2. “It’s the sun stupid” is threatening to take food off of too many people’s plates! Follow the money!
I agree. It appears to this old geologist that two unrelated events are being conflated. The extinction event is much more likely due to impact of extraterrestrial material with the atmosphere – perhaps the Carolina Bays and other apparently time-equivalent impacts are related – think about 500+ concurrent Chelyabinsk events – and the resulting disruption in the atmosphere and on the ground below.
The climate shift was quite probably associated with other completely independent influences. That they appear at about the same time is purely coincidence.
Don Easterbrook, after each sizable cosmic impact on Earth always follow 3 phases: 1. A sharp downdip of temps, followed by 2. a temp rebound to a level substantially HIGHER than at the cosmic impact date and finally, the last phase, 3,. a temp regress back to the lower temp level of the impact date — this mechanics produces a Z-shaped or high-voltage sign e.g. in the Greenland GISP2 temp time series. More on relation on effects of cosmic impacts and Z-type temp evolution at
http://www.knowledgeminer.eu/climate_papers.html,
there is no point of wild speculating around with volcanoes, dust, time span without first doing some reading on the empirical relation and the effects of a cosmic impact on climate change…regards JS
Don –
“the preceding late Allerod cold period. ” Actually, the Allerod was not a cold period. It was the interstadial, when temps reached close to today’s.
NO, they have not addressed the question of the length of the YD. Yes, of course 1300 years is too long to have dust up in the air. By a factor of 100 or more. The YD researchers have been bogged down dealing with the carping of their skeptics on the impact materials – which are very real. As this paper shows. Saying that materials that MUST be heated above 2200C are not indicative of an impact (and not possible with any Earth processes on the surface), and all the different ones are all spiking right there – what does it take for you to even look at their data? It ain’t ONE material that convinces – it is the suite of materials. Right now the focus is on making the case for the impact materials. The other questions can’t be dealt with just yet. It’s not an excuse; it’s reality.
The black layer being on 3 continents and with some evidence of it in northern S America, too, indicates a natural event larger than any in known human history. With essentially the same suite of markers in Syria and Belgium, something happened that was big. Super big.
I myself think that the single biggest question is that 1300 years – and then the even more abrupt RISE in temps.
At the same time, I do not take Greenland ice now or 13,000 years ago as a valid proxy for the state of the climate. The D-O events may simply be an artifact of the location. The GISP2 core suggests very big changes in temps, over seemingly impossible time periods. Nothing within the climate can do changes that big. They are all micro-forcings, with no capacity to do much more than a few tenths of a degree. Either something (perhaps at multiple times?) from outside the system intruded or we should consider that we are getting a false picture from the ice cores. At least as it pertains to global climate.
At the same time, it was not Firestone and the other YDIH researchers who first made a big hoopla about the YD. It was biologists and climate guys. And they have been at it for DECADES, with no resolution on the horizon. Firestone and all of them can’t help it if their C14 numbers kept coming back with 12.9 kya written all over them. If the dates came back with 37 kya on them some other scenario would have had to be dealt with.
And when they found mammoth bones immediately UNDER the black layer – with the black layer draped ON the surface of the bones and staining them – what were they to think? No connection at all? Not even. There they are, at 12.9 kya (now 12.8 with IntCal13), black layer, mammoth bones, spikes in nanodiamonds, spikes in several other markers for impacts. ONE marker is one thing. A suite of them is a whole other ballgame.
The 1300 year conundrum will still be out there. First things first.
Don Easterbrrok is 100% correct. This is the wrong explanation.
Exactly Mr. Easterbrook.
I thought my first comment did not go through. Sorry for the duplicate.
I’m skeptical. The event was more likely caused by electrical interaction between the planets that scarred them all in a solar system upheaval.
https://www.thunderbolts.info/wp/2013/06/07/earth-cycles/
Can someone please vacuum off the frozen mastodon, the frozen one with food in the stomach, and find the dust and micro diamond.
This convincingly supports the impact theory: http://cometstorm.wordpress.com/2011/04/06/a-different-kind-of-climate-catastrophe/
One of the most interesting talks on catastrophies I’ve seen.
http://sacredgeometryinternational.com/cosmic-patterns-and-cycles-of-catastrophe-dvd-preview
Based upon what I have learned about extinction of mammoths and other mega fauna, I find the comet hypothesis woefully inadequate. It is hardly settled science at this point.
Correct. The pattern & timing of extinctions doesn’t support the impact hypothesis.
Dinosaures were killed by a comet; Mammoths were killed by a comet ; humans will be killed by CO2
Not a comet in either case. A meteor contributed to demise on the non-avian dinosaurs. The meteor hypothesis for the demise of the Pleistocene megafauna is thin at best. The same & similar species also went extinct outside the region allegedly affected by an ET impact.
Read Otto Muck’s work for a full explanation. This is old news
Megafauna extinctions in North America do not correspond closely with the YD, although C14 & calendar year comparisons make for difficulty. In any case, different species & populations went extinct at different times, as nearly as evidence can be resolved.
For instance, island populations of ground sloths survived for thousands of years longer than on the continent.
Actually, at Blackwater Draw there were mammoth bones immediately under the black layer – which has been dated to 12.8 ya on many occasions. Not only was the mammoth there, but the black layer lay over and conformed to the bone. Not only that, but the black material was in intimate contact with the bone and stained the bone.
Outside the pygmy mammoths, no mammoth in the world dates past that 12.8 kya.
C14 vs calendar dating is a simple matter of looking the carbon14 (calendar) date on the IntCal13 graphs. Or, if you are lazy, there is software to do the comparing. It’s not difficult at all.
As to the claims of different times, people say that. So far in all my reading of papers on that, no one has shown any that lived past 12.8 kya. That mammoths died earlier? If the LIVED earlier, then of course they DIED earlier.
Pleas can you point me to the ground sloths? I’d be quite interested.
1.) How is a North American event supposed to have caused South American extinctions but not, apparently, Eurasian or African?
2. How is an event which caused a blip in temperature indistinguishable from a great many others supposed to have caused extinctions even in areas in NA which were west of the supposed fallout area? (But not outside of NA.)
3.) Why does UofC@SB think ‘science is magic’/’science is settled’ reporting appeals to the public? “..until recently, could only speculate as to why.”
1.) and 2.) both good and very valid questions. And ones that the researchers are well aware of. I’ve been on this for about 7 years or so, and I can tell you that the researchers on it are bogged down just trying to get people to accept their “forensic” results. There is a small group of hacks that the researchers think they have to please, so they are spending all their time on that. They do not have unlimited manpower. Give it time.
There are considerably more PRO papers and researchers than there are CONs. Some of them came out of the blue. Like last year some researchers at Harvard and Princeton found supporting evidence.
If you go into the voluminous lab tests in the Appendices to the different papers, you will see that this is serious stuff, very real. Some of the materials are impossible to create without the super-high pressure and temps in a hyper-velocity impact. So, if not an impact, then what? If it looks like a duck, quacks like a duck, and has duck feet. . .
There are multiple lines of evidence.
At least in those days they had climate change you could believe in. I wonder if they too had high priest predicting the end of the world. When exactly did they have their tipping point.
I’ll tell you what:
If you ever get around to reading the accounts of some of the indigenous peoples, it is not hard to start thinking that something actually DID come out of the sky, with a tail like a dragon, blah blah blah and killed a whole lot of people and shook the earth and caused all kinds of havoc.
So humans didn’t hunt everything to extinction?
Evidence still suggests that we did indeed have a big impact among the naive megafauna of the New World.
Hahaha –
Yeah, the idea of a few thousand guys on foot scouring the entire N American continent – in 200 years – and were able to FIND all of them, much less kill them. That soudnds plausible to me.
Especially when they were killing something bigger than elephants and curing and hauling the 5 tons of meat back – still on foot.
And THEN consider this:
There are only 14 kill sites on the whole continent, and those are where? Basically, like 95% of the Clovis sites are in the SE of the USA. (A site comprises ANY Clovis point, even one – even a broken one.) Google “clovis sites map” THERE ARE A LOT OF SITES. And hardly ANY out west. Where the mammoth kill sites are.
But how many kill sites are in the SE of the USA?
None.
Their families were back east, and they were out in Texas and NM and Arizona, killing mammoths and butchering them. To take the food WHERE? Back to Alabama? From New Mexico?
And BTW, they came up with that Clovis, Extinctor of Mammoths thing when they assumed that the only hunting Clovis man did was for Mammoths.
And you know what they are only now beginning to find out? They hunted rabbits and deer and raccoons and foxes – stuff you can sling over your shoulder and take back to camp to cook for dinner tonight – just like all hunting societies did.
So, with 95% of Clovis in the SE and lots of deer and such to hunt there, what were they doing out west, 1500 mile away?
Global effects of comet impacts and volcanoes (which can be triggered by comet impacts) has been a topic I’ve followed with great interest. I’m convinced they are effecting things on this planet much more so than we realize. Not only effecting the weather, but civilizations.
The last major impact coincides with the time of the Pleistocene–Holocene, and the Holocene extinction event. It’s the 6th great extension event on the planet.
Wooly Mammoths, Saber Tooth Tigers, Giant Sloths, and so many other animals, were pushed into extinction. Or, in the case of the early human inhabitants, were nearly made extinct. Humans then re-populated the N America with a second wave of migration. That’s the one you were probably told about in your high school history books, but humans were here for much longer.
Also coinciding with the time of the impact was the end of the last ice age, when much of N America was covered by a glacier. As the ice melted it created a huge fresh water lake covering cover of Manitoba, northwestern Ontario, northern Minnesota, eastern North Dakota, and Saskatchewan. It made all the “great” lakes added together seem like ponds in comparison. It was approximately the size of the Black Sea, about 170,000 sq miles.
As the lake filled, it eventually broke through draining through the Mackenzie River and then into the Arctic Ocean. That’s a MASSIVE amount of fresh water pouring into the salt water in the Arctic. So much so it would be a likely source of flood myths. This water was even flowing south through the Mississippi River.
This must have altered the global climate, and it would have altered the Thermohaline Circulation (aka Atlantic Conveyor Belt). Then there was another great draining around 8,200 years ago (or 6200 BCE), after more ice had melted. This last great melt happens to coincide with the the 8,200 yr climate event. Evidence for this event can be found in Greenland ice cores.
These melts were so large they would have increased global sea levels (~6ft).
The disruption to the Thermohaline Circulation would have likely triggered global cooling. Possibly by as much as 10 deg F. The total duration of the cooling was ~150 years, with sudden cold periods of ~60 years. Even more curious, global CO2 levels dropped ~25ppm.
Such a dramatic impact on the Atlantic’s thermohaline circulation would likely cause a shift in the latitude of the jet stream. This is like the current Polar Vortext, which is when the jet stream has shifted south and pushes the colder air from the Arctic over warmer lands. It would also effect global precipitation. Some ares become much wetter, while others become much drier.
Africa went through ~500 years of drought. The event likely given Mesopotamia the support for their irrigation, which gave rise to agriculture and the surprise of food. This in turn gave rise to the advancements of civilization. But then very suddenly (~100 years) the global climate seems to have corrected itself, and ended this unique weather phenomena.
The Burckle Crater may be the result of comet impact around 2900BCE. It’s about 18 miles in diameter, and it’s under the Indian Ocean at 12,500 feet below sea level. If this does turn out to be an impact crater, it would have caused a mega-tsunami of biblical proportion (e.g. mythical flood event that would have wiped out civilizations along the coasts).
It’s another example of how natural causes come along every few thousand year and dramatically change the global climate. There are a number of comet impacts that has effected civilization. I wish the historians were talking with the paleo-climatologists, and comparing their timelines.
The end of the Medieval Warm Period (MWP) created the Great Famine of 1315. The rise to the population explosion as a result of the good climate during MWP. It all came to an abrupt end with the shift to cold weather. The end of the MWP saw millions died after as crops failed for several years. The following few decades were some of the worst weather on record.
Along with the cooler temperatures were heavy rains throughout Europe. So much so crops failed and people starved. Without the hay to feed livestock, the animals also died. People were more concerned with survival than enlightenment. It wasn’t until the global climate recovered that we enter the Renaissance.
Meat preservation during this period became difficult and unaffordable since it was based on the use of salt, which was produced by evaporation but became nearly impossible due to high humidity.
Natural forces effected civilization was the Dark Ages. It was actually “dark.” There was hundreds of years of vocalic eruptions triggering global cooling. Hekla blew its top in 1300 and continued to spew its guts for one full year! It was called the “Gateway of Hell” by the Europeans.
There’s a scale for measuring eruptions, the Volcanic Explosivity Index (VEI). When you get a VEI 4 you’re at the point where it will effect climate. Not only was Hekla a VEI 4, but it was spewing its guts throughout the Dark Ages. That’s just one volcano. Then in 1362 Iceland’s another monster blows it’s top and is bigger than the famous Mount Vesuvius that buried Pompeii. You can find a history of volcano eruptions throughout the Dark Ages.
The destruction of the very advanced Minoan civilization was caused by the Santorini eruption in 1645 BC. This monster was a mega-eruption at VEI 7. It was an island, and when it blew its top the island was gone. This left a crater below sea level, causing the ocean to rush into the gaping hole causing an even bigger explosion. All that water (~20 TRILLION gallons) was instantly vaporized, and thrown high into the atmosphere. Some of it froze and remained floating around the world as tiny particles of ice (mirrors). This reflected solar radiation for several years, causing an even longer and colder volcanic winter.
The Santorini eruption was seen in ancient Egypt. They even had a tsunami wave reach their coast. That eruption also triggered the expected famine and diseases. In fact, the story of the Exodus and the ten plagues of Egypt can be explained as a result of a volcano.
The Huaynaputina eruption in 1600 triggered a couple years of volcanic winter, causing the Russian famine of 1601-1603 when more than half a million people died.
I’m amazed by the irony of how Briffa’s work on tree ring and climate is so focused on CO2 levels and temperatures. That same data can be used to show the effect of volcanoes, which should be correlated to events in civilization.
The warm & cold centennial-scale climatic cycles observed during the Holocene & prior interglacials & glacials are not caused by volcanic eruptions.
Hekla for example was more active during the Medieval Warm Period (c. AD 900-1400) than it was during the Little Ice Age (c. 1400-1860) or so far in the Modern Warm Period (c. 1860 to present). Here are its VEI 3, 4 & 5 eruptions for each cycle. The year given is for when the activity began, but six lasted more than one year or included back to back annual eruptions.
http://www.volcano.si.edu/list_volcano_holocene.cfm
Medieval WP Eruptions of Hekla (~500 years):
1104: 5
1158: 4
1206: 3
1300: 4
1341: 3
1389: 3
Little Ice Age (~460 years):
1510: 4
1597: 3
1636: 3
1766: 4
1845: 4
Modern WP (~154 years to date):
1947: 4
1970: 3
1980: 3
1991: 3 (same year as Pinatubo)
2000: 3
If there be any correlation at all, it’s that great activity warms rather than cools the climate, which is indeed what researchers have generally concluded, despite short-term cooling of weather for a year or two, possibly a few years for the very biggest, tropical eruptions.
Just to be clear, I’m not claiming volcanoes are driving climate. I was talking about how comets and volcanoes can disrupt civilizations. They also effect weather, in a number of ways.
As for the large time scale changes in climate, my understanding is that it’s driven by the Milankovitch cycles.
Jim –
Good stuff. Keep at it.
But dump the Lake Agassiz thing. It didn’t happen. The ice was still too far south at the Holocene start. The ice was not retreated enough in time to do any of that. Wallace Broeker was the guy who came up with that idea, and he admitted a few years ago that he had to abandon the idea.
But he didn’t come out very very vocal admitting his mistake, and so many people don’t even know that he dumped the idea.
OTHERS, though, think that an outflow down the Mackenzie River and exiting into the Arctic Ocean up near Alaska is just as good. But that is like 4,000 miles and at the other far corner of Canada. Even f fresh water went that way, it had to make it past the Canadian Archipelago and Greenland in order to end up east of Iceland and screwing with the Gulf Stream.
Anyway, that is a dead horse.