UPDATE 3/12/12 – a new study presents very strong evidence for the comet theory, see here
Bishop Hill alerts us to this news item in Miller-McCune, a policy and research website. It seems the scientific claims can’t be replicated by others…but wait for the kicker.
OK, having read that primer, it looks like a slam dunk for falsification, right?
Yet, the scientists who described the alleged impact in a hallowed U.S. scientific journal refuse to consider the critics’ evidence — insisting they are correct, even though no one can replicate their work: the hallmark of credibility in the scientific world.
…
“We are under a lot of duress,” said Kennett. “It has been quite painful.” So much so, that team members call their critics’ work “biased,” “nonsense” and “screwed up.”
…
“It is very peculiar,” Holliday said. “They propose an idea, a study contradicts it, then they criticize the scientists or the work.”
Hmm, where have we seen this sort of behavior before? Man o’ mann, I wish I could remember where contradictory peer reviewed scientific replication was dismissed as “biased,” “nonsense” and “screwed up.”.
But it reminds me of what might go on in scientific circles above Monks restaurant:
The news item in Miller-McCune is highly recommended reading
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Murray says:
May 18, 2011 at 3:45 pm
Personally, I like this variant of the theory http://cometstorm.wordpress.com/
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Yes, that site is absolutely fascinating & a must read. It’s getting to the point where it’s quite convincing.
Thanks too, to Feet2theFire for your links & comments. This is an evolving story. I’d bet 20 yrs from now geologists will wonder how they didn’t make the connections to this evidence earlier, just like continental drift. The prospect of a firestorm of fragmented comet-strikes devastating a continent in minutes so recently in the past is rather sobering.
Funny thing, those asteroids, that only kill the big game animals and leave the little critters largely untouched. And another thing, the extinctions didn’t occur all at once: they disappeared mostly within a couple of thousand years after the arrival of humans, some early, some late. And another thing, everywhere humans went, big animals went extinct within centuries: in Madagascar, Australia, lots of Pacific islands, including big birds in Hawaii andNew Zealand–everywhere humans went they wiped out the biggest animals.
This meteoric explanation is a pathetically unscientific fairy tale. Of course I said that a few times about the K/T event too, but we know when humans arrived in Australia and Madagascar and Hawaii, and North America, and hundreds of islands, and as close as the archeologists can tell, their arrival spelled almost immediate doom for ecologically naive game. See:
http://en.wikipedia.org/wiki/New_World_Pleistocene_extinctions
…which tells how most of the surviving species in North America were those which had evolved together with humans in the Old World, and had only recently migrated to the New. They knew enough to keep their distance from the two legged hunters. And there do appear to have been regional extinctions and eventual domestication of bison.
This all reminds me of the “discovery” of the “Flood” boundary in Mesopotamia a century ago. Problem was, they later discovered older flood accounts on tablets beneath the flood layer. And likewise, New Wrold species that went extinct did so on both sides of the Younger Dryas. The asteroid theory is an explanation in search of a problem–the correlation between human arrival and game extinction is very high. I could believe in CAGW by way of an annual 3mm sea level rise more easily than in ET Pleistocene extinction.
–AGF
Peter Kovachev, What I was trying to communicate was that with the current spotlight on “intellectual property” protections . . .
http://news.google.com/nwshp?hl=en&tab=wn&q=%22intellectual%20property%22%20protection
That if I access this book via a library . . . I have complied with C.Y.A. protocals. /sarc
It appeared to me that there was a common law copyright on the link I provided . . .
http://creativecommons.org/publicdomain/zero/1.0/
That’s all!
lowercasefred said :
“Stones do not fall from the sky.”
Says who?
So many thousands of years and they still haven’t been able to kill all the kangaroos..
http://australianmuseum.net.au/Megafauna-extinction-theories-patterns-of-extinction
Climate change what done it. When the food source disappears. As later with the Younger Dryas and the Irish Elk.
The Australian story should be particularly noted by those who want to blame everything on human destruction – it wasn’t the Aboriginal natives burning all the trees which then changed the landscape etc., it was the end of a climate cycle which dried up the lakes in summer, or completely. This also affected the humans who had been living with these mega beasts for some 30,000 years.
This a typical blame the natives site – http://www.convictcreations.com/aborigines/megafauna.html
Perhaps it makes some whities feel better for stealing their land ..
Very simple. Kangaroos don’t need water. That means they can go where people can’t. Try another species. –AGF
This Australian Museum website supposes that the the last ice age was worse than the previous ones, which we know to be nonsense. Big ice ages wipe out much of the evidence of the smaller ones, and the last one was the smallest of the four main ones. Why didn’t the earlier ice ages wipe out the megafauna? Because there were no people there. –AGF
@AG Foster –
The overkill hypothesis is somebody’s wet dream. it is very difficult for people in this world of 6.5 billion people to comprehend how sparsely the population of, say, Crystal Lake, Illinois (around 20,000) would fill 8 million square miles of North America. With half of them being women and half of the males being under the age of 12, it leaves about 5,000 hunter-age adult males. If each one covered five square miles a week (very doubtful), it would take 32 years (probably 125% of a lifespan – and 175% of a hunting career) to cover the entirety of NA, if they didn’t go over the same ground twice. And all the megafauna would have to not wander into the already covered area, which would give them 32 years of protection (0n average) from bumping into one of the 5,000. And if the hunters missed any, by the time they returned to a habitat, the megafauna would have 32 years on average to reproduce.
The idea of them scouring every habitat of every large animal in that area is so silly, I can’t believe that academics could ever have fallen for that. Don’t they have any common sense at all? It is Einstein’s Random Walk, with a dead carcass at every juncture.
I won’t even go into WHY they would kill such large beasts in such numbers. They certainly couldn’t have eaten them all. I get the impression that modern scientists believe that Clovis man was as carnivorous as modern day capitalists. It is just one of those forms of “Man, the evil creature, the one that has no right to live on Bambi’s planet.”
Laurie Bowen says: “Peter Kovachev, What I was trying to communicate was that with the current spotlight on “intellectual property” protections . . .” (May 19, 2011 at 9:51 am)
Oh, I see, sorry, didnt get it. I did notice too that it’s a Commons license, and wondered why as the book would still be protected.
It took the whitey to wipe out the food source of the Native Americans..
Back to Oz: http://www.abc.net/au/science/ozfossil/megafauna/climate/climate.htm
This is ridiculous. There were hardly any people at all in any numbers in any one place – a population around 5 million globally at the beginning of the Holocene – and these mega animals were in vast areas for all practical contact, empty of humans. Humans no doubt hunted them on the edges, or followed herds as did the Native Americans, but to think that so few with primitive weapons, though effective, killing for their immediate food requirements, could wipe out all these mega animals globally, is just absurd.
And on foot!
If you don’t know anything about the Bushmen of the Kalahari, well worth getting to know. They still hunt, those that haven’t been forcibly moved off their land.., in traditional ways.
Here’s an Attenborough on their hunt: http://video.google.com/videoplay?docid=-490028831040819475#
And do keep to the end, because you’ll find a common theme among hunter gathers the world over, respect.
There is nobody on the planet who has any notion what the population was 10,000 years ago. You all parrot the most hopelessly specious guesswork. Try to put together some reasoning to back up your wild figures! You can’t, because neither you nor anyone else has any basis by which to estimate ancient populations. Let me let you in on a little bit of info. The population of North Africa was about as great as the population of Europe only 2000 years ago. How do we know this? Take one tiny example. History tells us that three philosophers in the Roman period believed the earth was flat. None of the three were from Europe. Two were from Africa and one from the Near East (not Africa). One, Lactantius, became tutor to Constantine’s son. Lots and lots of famous “Greeks” and “Romans” came from Africa, like Augustine, and Eristosthenes, who calculated the size of the earth. In fact if you were to do a census on the provenance of famous Hellenistic thinkers you would find that about half were not from Europe. Leptis Magna provided the wheat for the Roman dole, and one emperor, Septimius Severus. Thousands of years ealier much or most of the Sahara was savanna, as the ubiquitous rock art proves. You can even find in the deserts of Sudan pictographs of people lassoing a giraffe, about 7000 years ago.
You might want to take a look at the book “1491” to get some idea how densely populated the Americas were before 1492–tens of millions, probably close to a hundred million natives. Traditionally low numbers are based on a perfect absence of data, and an absence of any sophistication in population studies. This “noble green savage” nonsense is truly a kindergarten fairy tale. All humans in all ages have been multiplying at the expense of the animal competition. Hundreds of perfectly factual examples may be provided, where we know with certainty that climate had nothing to do with the extinctions. And I repeat, do you people really think the climate did something in the Holocene that it had never done before? What utterly preposterous nonsense. You are welcome to retain your belief but don’t flatter yourselves into thinking you’ve got a lick of science to back it up, ’cause you don’t. Every passing year piles up more evidence against it, and it’s only the most irrationally precommitted who insist on defending it.
Why don’t you sit down and make a list of animals you can admit were wiped out by humans, just to show you are able to approach the subject rationally, and we’ll go from there. –AGF
AGF,
I don’t know this for a fact, but I’d guess your first sentence is wrong.
@AG Foster –
I think you may have mis-typed. Did you mean “North Africa”? Or North America?
Yep, read “1491.” Great book. Terra preta may be the single best development in the history of agriculture – one that the ancient South Americans created, yet today’s scientist are having a great deal of trouble translating into something real for today. But when we do, watch out.
But A., the numbers in the book are not agreed to by many, though I tend to agree with them in principle, intuitively. (But where are all those skeletons, or graveyards?) You reading the end result of 11,000-12,000 years of population growth and saying that the population was in the millions at that time is unfounded in the extreme.
ALL of the population figures for past centuries – not to mention previous millennia – are mostly guesswork, even by those who think they are. You are correct about that.
But I would put a lot more money down as a bet on 20,000 (+/- 2 magnitudes) people using Clovis points than some substantial percentage of the “1491” numbers.
Look up populations for cities and countries from just 200 years ago. In 1800, no city had 1 million people. The world population was only 2.5 billion about the time I was born (around 60 years ago). It is up about 2.3 times that now. The numbers for farther back in the past did not grow nearly as fast as now, due to sanitary conditions and lack of medicines. Until the Industrial Revolution, population was a slow grower, but 10,000 years is a lot of years of slow growth. When centralized civilization happened, populations grew (subject to epidemics, though).
Without centralized civilization and its infrastructure, please explain to me how the population was more than a few score thousands, only 1,000 years after the Asian influx over Beringia? If the people were much more than nomads, please tell us what you base such logic on. They had to be somewhat nomadic, after all, if they were to have covered all the bases in order to kill all the megafauna in North America. They certainly didn’t do that while rocking on the porches of their mansions.
Those “1491” numbers were based on high and centralized civilizations, even if they were assembled in smaller communities than we have today. Please, show me where millions could inhabit the Americas without an infrastructure tied in with a centralized civilization.
I don’t look on peoples of the past as noble savages, not in the slightest. Being in a world without infrastructure, they were so much closer to the realities of the functioning world than we are now, and that to me speaks volumes about how tough-minded and hard-nosed they had to be, in VERY practical ways, all across the board. Hard-nosed is not noble. Living close to the land isn’t either. Ask any hippies who lived on communes in the 1970s. Given a comparable infrastructure, I feel confident the ancient indigenous peoples would have been able to keep up with what we do today. I laugh up a storm when arkies treat them like village idiots, fearful of the skies and supposedly referring to insignificant dots of light in the night sky as “gods.” That is a fiction of the arkies. And I think they were no more noble than we are, either – just less disconnected from the world around them.
If you assert that the climate did NOT do something at the beginning of the Holocene, you are as ill-informed as you suggest I am. The Younger-Dryas Stadial lasted for about 1,100-1,200 years, and the temps dropped by about 25-30F, in a matter of less than 20 years – and stayed that way for almost the entire duration of the stadial. That is not me talking, but the scientists. You’re blowing it out your nether orifice. I am not one of the scientists, but I’ve been informing myself about this period for quite some years. I don’t know everything, nor do I know any part of it in full – but I am a well-informed lay person. You claiming that nothing happened to the climate at the Pleistocene-Holocene threshold is totally non-informed (the formal definition of ignorant). There is much more than a lick of science backing up what I have discussed here. When I give an opinion, I try to spell that out. When I talk about the science, I source it when I can.
And, Smokey’s guess is correct: There ARE people who have a pretty fair guess about what the population was 12 kya. Do I think they got it within 50%? Probably. Do I think they are off by 3 or 4 magnitudes? No.
You talk about the Overkill Hypothesis like it is God, then because I say it was never as sound idea in the first place, you make ad hominem attacks on me. Nice science. There might be a place for you with Michael Mann.
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A G Foster says:
May 18, 2011 at 8:26 pm
After all, the Caucasion population of North America required only 400 years to reach 300 million.
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Either a bad joke, or a typo that’s too high by 2 orders of magnitude.
Well sorry, AG, I misread your line. But 3 million is about right for the native US & Canada population when Columbus arrived. Mexico & Central America might have had an additional 3-4 million with their relatively advanced agrarian cultures.
Re.: Feet2theFire says:
May 19, 2011 at 10:39 pm
@AG Foster –
I think you may have mis-typed. Did you mean “North Africa”? Or North America?
Nope, I meant North Africa. Just trying to show how little the climatologists know about the historical effects of climate on population. Try to find an anlysis which acknowledges that climate change was responsible for the decline of Islam and the rise of Christianity. The population of North Africa hit a minimum in about 1900, and began to rise again.
When you speak of a 30 degree temperature change, you can only be referring to the local effect of newly established but permanent snow cover–not a global rise; that would be more like 3 degrees. And true, ice does drive out most species, as in the trivial case of the Irish elk: ice melts, elk move in; ice returns, elk starve. But you seem to have no idea what you’re up against when you speak of climate change extinction.
I never denied the suddenness of the Younger Dryas, but if freezing is invoked as an extinction agent, how do you explain the fact that mammoths survived only in the northernmost islands, except by supposing that they were apparently out of human reach? Mammoths survived on Wrangel Island up till 4000 years ago, about the time Eskimo technology allowed humans to penetrate so far northward. Clearly mammoths survived the two Dryas events. And if you invoke climate change as the cause, how do you explain the relative lack of extinctions in Eurasia at the same time, where the big game animals evolved together with the bipedal hunters?
As for population growth, the rules are simple. Where the supply of food is in excess the population increases until the supply is no longer in excess. Any time land bridges are formed, like the Isthmus of Panama or Beringia, animal crossings lead to great ecological disruption and extinctions ensue. But successful colonization in either direction may occur. So horses and camels which evolved in North America colonized Asia, and camelids earlier crossed into South America. So did lots of species, which wiped out hundreds of indigenous marsupial and edontate species, through predation or competition. As we speak feral iguanas are wreaking havoc on native Puerto Rican birds.
Humans are no different. Presented an easy supply of “ecologically naive” game, which have no more fear of humans than did the dodo, they killed them, ate them, and multiplied. And kept multiplying until the mortality rate of the big game surpassed its birthrate, at which point they are lucky to survive on remote northern islands. When the big game are gone the hunters turn to smaller game, and when food becomes scarce they turn on each other, and the population plummets. Disease was not a problem in North America. At that point the carnivores starve and die off as well.
So…try to explain the survival of mammoths on Wrangel Island while insisting on their extinction further south due to glaciation or “grassification” or meteors. I’m curious. –AGF
Feet2theFire,
This thread is still going? Cool. I’ve been so busy with my new project that I have not had time to properly read your comment, process it, and formulate a response. I have just completed a review of the latest research in carnivore evolution which included some data relative to this discussion. I think I can make a pretty strong case for the Grey Wolf being partly responsible for the Mega-fauna extinction, which, BTW, is not all that unique. I just don’t have the time right now, but this afternoon I should.
Al Gored,
I think you might have misunderstood what I am trying to say. I am not claiming that Humans were not a factor, but rather that they had help from the conversion of grassland/prairie to forest/woodland and another predator, like themselves who not only can take game bigger then itself, but is not dependent on that game, and also likes to live in forests, but has no problem hunting in grassland.
There’s an elephant in the room!
There was once an elephant in a room. The beast was the subject of lifetimes of careful study, and speculation, by skilled, and dedicated, specialists of precise, but very limited, vision. The man who studied a leg said the elephant is like a pillar. The one who studied the tail said the elephant is like a rope. The one who studied the trunk said the elephant is like a tree branch. The one who studied the ear said the elephant is like a hand fan. The one who studied the belly said the elephant is like a wall.
The nature of the beast was all very contentious, and controversial. And even the fleas on the elephants backside joined in the debate, with the assertion that “This is our ever unchanging world, you fools!”. Until one day, a person came along who could see the whole beast from a distance, and he explained to them:
“All of you are right. The reason every one of you is telling it differently is because each one of you has perceived a different part of the elephant. So, actually the elephant has all the features you mentioned. But there is so very much more to the beast than any of you know. You just need to get enough distance to see it all in context”
The blind scholars all dismissed the new viewpoint as heresy. They argued that it had never been established among them, that ordinary vision was a valid tool of science. So, since this new, and heretical, viewpoint flew in the face of all they had so carefully, and painstakingly, confabulated about the the beast, they quickly resolved to ignore the new viewpoint. And to get on with their life’s work of studying, debating, and confabulating theories as to the true nature of the elephant in the room.
Gradualism, and Uniformitarianism, only work until something sudden, and chaotic happens.
One of the biggest mysteries I’ve ever confronted lies in the question of how theoretical geology could be so far removed from the empirical reality now clearly visible, and legible, in modern 21st century satellite images.
It didn’t take much digging in the history books to figure out where the Earth sciences went wrong.
The root problem with the thinking in the Earth sciences goes all the way back to Gottfried Leibniz, in the early 18th century, and his slogan of ‘Natura Non Facit Saltus’, (Nature does not jump). Leibniz may have been a mathematical genius. But he wouldn’t even pass a 5th grade geology test of today. Yet he had the full backing of governments, big business, and the big churches. Because he believed, and taught, that the Great God of the Universe had created planet Earth, with all its flora, and fauna, just for us, and to do with as we damn well pleased.
The old clichés like ‘buying a pig in poke’, ‘don’t let the cat out of the bag’, and ‘empty sack of lies’ all have their roots in the same old con. It went something like this: At an old country fair, a con artist would approach a likely looking mark to sell him a piglet in a ‘poke’ bag. But it’s not really a pig in the bag; it’s a cat. The cat wiggles, and squirms, just like a little pig when you poke him through the bag. And as long as the bag stays closed, the con works just fine. But as soon as the bag is opened, the cat escapes. And the victim is left holding nothing but an empty sack of lies.
Carl Linnaeus, and Charles Darwin, loved Leibniz. And they both quoted him verbatim. He managed to almost completely eliminate any academic consideration of episodic worldwide catastrophes from western thinking. And by the time James Hutton, and Charles Lyell, came along, most geologists were well-conditioned followers of his way of thinking. Hutten gets the credit for the origin of Uniformitarianism. Charles Lyell just popularized his ideas in 1830, when he published his book ‘Principles of Geology’. But Hutten, and Lyell, just picked up on Leibniz’s thinking, and ran with it.
They weren’t brilliant geological thinkers either. But their unquestioned uniformitarian/gradualist assumptions, based on the idea that the earth was shaped only by slow-moving forces still going on around us today, and expressed in the slogan of “The present is the key to the past”, has become the foundation postulate of the Earth Sciences ever since. Governments, and big institutions, loved it. And they bought it like a pig in a poke with generous funding packages that came with rules that shut the door to any consideration, or publication, of theories of sudden catastrophic events, as a possible driving force in the geo-morphology of this world for more than 150 years. That’s a cruelly long time time to leave the poor kitty in a bag.
But the questions of just what the hell happened around 13,000 years ago that caused the extinctions of the mega fauna in North America, the disappearance of the Clovis culture, and a return to Ice age conditions that lasted more than a thousand years, has caused us to take a closer look, and I’m afraid we’ve let the cat out of the bag.
The most glaring flaw in the Younger Dryas Impact theory as written is that it is impossible to construct an impact model with a 4 mile wide bolide that has enough time in the atmosphere to break up completely, and scatter fragments over a continent sized area without making a good sized crater somewhere. And “where’s the crater?” has become the rallying cry of opponents of the hypothesis. But from Comets, Catastrophes, and Earth’s History by W. M. Napier we read ,
The astronomical data on the Taurid complex is as good as anything you can dig up with a pick, and a trowel. So, if he’s correct, then we should expect to see the planetary scarring, somewhere on this continent, of a very large cluster impact event of smaller fragments. We’re not looking for a single large crater, or impact structure.
What if we set Sir Charles’s unquestioned 19th century, gradualist, assumptive reasoning aside for a minute and see what we can find? Anyone ever hear of the Odessa crater, in west Texas? What about all the other craters in the area? Don’t take my word for it. Look for yourself. In the world according to Google Earth, the Odessa impact was only one in a vast cluster event that produced thousands of them in a wide area that includes most of eastern New Mexico, and west Texas. Set your eye height to about ten miles, and liberally scattered among the oil fields of west Texas, and eastern New Mexico, you’ll find too many craters in very good condition, and averaging 100 meters wide, to count.
Anywhere else in the solar system no one would hesitate to call them impact craters. But here on Earth, the academic community will entertain almost any fantastical theory for their formation. As long as that geologic theory does not evolve a catastrophic event.
If those thousands of pristine craters in the south west aren’t impact craters, then how did they form in such a wide variety of terrains?
Gradualism was in large part an appeal against a biblical creation of seven days or seven thousand years, and against the Noachian Flood, and was a vast and indispensable stride forward. And the neo-catastrophists mostly took their cues from Vellikovsky. It took some time to get the K/T event any respect but it has it now. Likewise it took a little time to understand that more sediment is deposited during a hundred year flood than in the hundred years in between. But many still see in Pangea vindication for the post-deluvian Peleg, who was named after a dividing earth (read “land”) –that is, Pangea broke up only a few thousand years ago.
The circumpolar current is a shadow of what was before the Isthmus of Panama arose, which was in turn a shadow of what was before Africa crashed into Asia. Consider what a homogonizing effect on climate such a current would have had, and consider what a cooling effect on climate the rise of Panama had. A very slow geological process gradually switched of a nearly global system of circulation. Such events seem to be more common than global extinctions due to asteroids, once every hundred million years or so. We are fortunate to have Jupiter and Saturn out their sweeping up the comets, keeping our little earth safe, most of the time. Recent ET events are certainly possible, but inherently unlikely as explanations for recent events–they should remain at the bottom of the probability list as agents of change.
Humans should remain at the top. –AGF
AGF said:
Pure uniformitarian assumptive reasoning. What about the craters mentioned above? Who did some real science on them?
The moon shows how common craters must have been on this geologically active earth, but the fact remains that planetoids and smaller masses have aggregated in the course of the solar systems history, making annihilating impacts more rare all the time. Shoemaker-Levi showed LaPlace was right in the way Yuri Gaganov showed the earth was round. That comet had been orbiting Jupiter for several decades before it impacted. It takes the gravity of two bodies to capture a third, and Jupiter is the bad boy that helps the sun do it. Jupiter is also capable of propelling a comet clear out of the solar system, but if and when it captures one, its moons make sure it won’t stay in orbit for long.
So no, this is hardly idiosyncratic speculation–the class of “Jupiter comets” are taken by current theory to have become such through Jupiter’s tremendous gravity. We may have been very lucky to have lived in the time of a comet impact on Jupiter, but it is probably no coincidence that that is what we have seen rather than an impact with the sun. Jupiter is like its own little solar system, with moons as big as earth, waiting out there like a spider to trap the comets, and leave earth safe enough for life to evolve and flourish, most of the time. –AGF
Word salad sucks. Give us a break!
Leave off the condescending, and impertinent, uniformitarian preaching, and gradualist inter-assumptive confabulation. Believe it or not some of us went to school too. And we are well aware what ‘Most geologists agree’ about regarding the grand uniformitarian assumption. And the naïve fantasy that catastrophic impact events don’t happen. And in spite of the fact that it was adopted without question as the foundation postulate of the Earth Sciences in the early 19th century, we remain to be convinced that all geomorphology is the work of slow, and steady processes we see going on around us today, or that ‘The present is the key to the past’. Or that impacts happen at a slow, and steady, rate. The astronomical data does not support those silly, and naive assumptions. Nor does the geological record. But that’s beside the point.
You’re completely dodging, and ignoring, the question. What about all the small craters in New Mexico, and West Texas? The empirical fact, obvious for all to see, is that they do exist, and in vast numbers, and they are in very good condition. Anywhere else in the solar system no one would hesitate to call them impact craters. Yet here on Earth, the academic community will entertain almost any fantastical theory for their formation. As long as that geologic theory does not involve a catastrophic impact event.
But if those thousands of pristine craters in the south west aren’t impact craters, then how did they all form at dang near the same time? (The surfaces they’re in all date to the late Pleistocene.) And in such a wide variety of terrains? Can anyone show me where someone has done some real science on them?
Or are we supposed to go along with the high priests of the church of the Grand Uniformitarian Confabulation, who’ve always taught that we should assume without question that such things do not happen at all? And ignore the simple empirical fact that the planetary scarring of a geologically recent super cluster impact event in the American Southwest is as obvious as spilled paint in a driveway?
Heck, they’re not even the only ones. There is also a whole slew of oblique impact craters from a cluster of objects the hit the late Pleistocene/Early Holocene sediments of the Red Rock River valley in Southwest Montana. That cluster of fragments hit at a very low angle coming from the southwest. And they produced oval impact craters. And if someone should want to actually do some science there, the ejecta from the oval crater at 44.642265, -112.077185 was blown over the top of, and is blanketing, one of the ancient meanders of the river at 44.644033, -112.076880. The stratigraphic horizon at the interface between the material of that ejecta splash and the ancient riverbed should give us materials we can get a C14 date from.
There is much science that remains to be done. And much data to be collected. But rumors that the Younger Dryas Impact hypothesis has been disproven are premature, and greatly exaggerated.
The existence of a bunch of craters in the desert that haven’t been studied makes for a pretty poor theory for Pleistocene extinctions. Until they’ve been dated why should I be expected to think they have anything to do with the problem. You seem to be assuming they are the same age. I would assume they are there because of the slow rate of desert erosion, not because they constituted a single event.
If you are claiming that both Dryas events were caused by meteors that landed in the same South West desert, well that really stretches my credulity. Sorry, but a bunch of unstudied craters, whether they landed in rapid succession or centuries apart, doesn’t explain the disappearance of species which seem to have gone extinct one by one over a period of several thousand years. –AGF
beng says:
May 20, 2011 at 6:29 am
“Well sorry, AG, I misread your line. But 3 million is about right for the native US & Canada population when Columbus arrived. Mexico & Central America might have had an additional 3-4 million with their relatively advanced agrarian cultures.”
Huh? Where did you get your numbers?
The one for Mexico+ is not even close to the estimates I have seen.
And many Native North Americans, notably in the southwest and eastern US, also had advanced agrarian cultures.