NOVA: Last Extinction. (Hat tip: Anaconda).
Watch it here.
"...12,900 years ago a comet slammed into the Earth. This cosmic catastrophe would have devastated the great land animals."
"This lead to wildfires over great areas."
"The larger the animal the more devastating the effects of this would have been. It would have been hell on Earth. And a very bad day."
Thus the extinction of the Biblical giants.
So how do the mathematicians react? By quoting Carl Sagan of course!
"...it's just extraordinarily improbable. And when you're making an extraordinarily improbable claim you need extraordinary evidence. And I haven't seen any extraordinary evidence." -- Mark Boslough, physicist, 2009
Hmmm. So I guess mass extinction of giant megafauna isn't extraordinary evidence? What would constitute extraordinary evidence?
"You have improbability stacked upon improbability. We're talking about something that may happen only once in the entire age of the Earth." -- Mark Boslough, physicist, 2009
So what left giant impact craters all over the face of the Earth? And what wiped out the dinosaurs? And what caused the KT boundary? These science deniers are hilarious. It's amazing they're employed.
"And I have a hard time accepting something like that happened that recently." -- Mark Boslough, physicist, 2009
So what wiped out the megafauna? The tooth fairy?
"It seems a little far fetched. There's a lot of species that did not become extinct which would be hard to explain why weren't they afffected if all these other large mammals were why weren't deer and elk and bear affected? Why did they survive?" -- Gary Haynes, archaeologist, 2009
Hmmm. OK ... so I guess that means that there are no impact craters on the Earth. No impact craters on the Moon. No impact craters on Mars. Shooting stars are mass hallucinations. The tooth fairy wiped out the dinosaurs. And the KT boundary is actually Dark Matter.
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36 comments:
@ OilIsMastery:
Apparently, you liked it. I thought you might.
I mean the documentary laid out so many different lines of scientific evidence that you posted on and was discussed, here, on this website.
In a way, it was like a review of already covered material.
It is gratifying to have issues and scientific evidence presented on mainstream T.V. which you are already familiar with.
A point of interest from the program. At the 12,900 year boundary, not only did the large animals disappear, but also the evidence of the Clovis people disappeared, too.
It is well worth watching the documentary if you have interest in this area of science.
Anaconda,
Loved it. Thanks for the headsup...=)
@OIM "So what wiped out the megafauna? The tooth fairy?"
OIM, you seem to be under the incorrect impression that only an asteroid strike can cause a mass extinction. For example, there is growing evidence that the largest mass extinction in Earth's history, the Permian-Triassic extinction of ~250 million years ago may have been caused by volcanism - specifically the massive lava fields called the Siberian Traps which were formed at this time.
Other extinction events of megafauna had nothing to do with asteroid impacts, but rather with Homo sapiens, the arch-predator. For example, the giant flightless bird known as the Moa inhabited New Zealand for thousands of years. Then the Maori people, the first human beings to arrive in New Zealand, arrived in c. 1300 CE. By 1400 CE the Moa was extinct. Just a coincidence, right? Where is the asteroid impact in New Zealand at this time?
Tom,
So what caused the giant impact craters all over the face of the Earth?
And what caused the KT boundary and the black mat?
@OIM "So what caused the giant impact craters all over the face of the Earth?"
These are asteroid impacts IMHO. I guess according to you EU folks these are "electric arc scars" which are presumably the locations where interplanetary Birkeland currents connected with the earth. Needless to say I don't subscribe to that viewpoint.
"And what caused the KT boundary and the black mat?"
An asteroid impact most likely. I'm not saying that asteroid impacts can't cause mass extinctions. All I'm saying is that there are also other causes, including the actions of mankind.
Your argument appears to be a rather elementary syllogistic fallacy of the form:
All A cause B
Therefore all B are caused by A
Tom,
"I guess according to you EU folks these are "electric arc scars" which are presumably the locations where interplanetary Birkeland currents connected with the earth. Needless to say I don't subscribe to that viewpoint."
You shouldn't paint all EU folks with the same brush. I don't paint all you creationists with the same brush.
"An asteroid impact most likely."
Not much difference between an asteroid and a comet imo.
"I'm not saying that asteroid impacts can't cause mass extinctions. All I'm saying is that there are also other causes, including the actions of mankind."
Mankind domesticates animals and saves animals from extinction.
"Your argument appears to be a rather elementary syllogistic fallacy of the form:
All A cause B
Therefore all B are caused by A"
It's not my argument. The argument was published in the Proceedings of the National Academy of Sciences.
@ Tom Marking:
Have you read the abstract provided by link from the Proceedings of the National Academy of Sciences?
How you watched the NOVA documentary?
I didn't get from the post that OilIsMastery attributed all extinctions to meteorites or comets. Or that Man couldn't cause extinctions in certain instances.
So why the false atrribution, Marking?
Marking, you are on the wrong end of this stick.
Perhaps, if you weren't simply out to contradict, you would have been more circumscribed in your comment. And limited it to what OilIsMastery did say instead of going off into a tangent on what he didn't say.
@OIM "I don't paint all you creationists with the same brush."
All you CREATIONISTS? ROFLMAO. That's a good one. Very funny.
"Mankind domesticates animals and saves animals from extinction."
Have you ever heard of the Dodo bird or the Passenger Pigeon?
"It's not my argument. The argument was published in the Proceedings of the National Academy of Sciences."
As usual, what you say the URL says is NOT what it says. Nowhere in the abstract does it say that all mass extinctions are caused by asteroid impacts.
@Anaconda
"Have you read the abstract provided by link from the Proceedings of the National Academy of Sciences?"
Yes, I read the abstract.
"How you watched the NOVA documentary?"
No, but I plan to, soon.
"I didn't get from the post that OilIsMastery attributed all extinctions to meteorites or comets. Or that Man couldn't cause extinctions in certain instances."
Hmm, perhaps you need to pay attention. My comment was "I'm not saying that asteroid impacts can't cause mass extinctions. All I'm saying is that there are also other causes, including the actions of mankind." OIM's response was "Mankind domesticates animals and saves animals from extinction." So you see the dichotomy, don't you? I acknowledge explicitly that asteroid impacts can cause mass extinctions. OIM has not explicitly stated that human activity can cause extinctions. That may be your assumption of his views but he has not stated it.
"So why the false atrribution, Marking?"
What false attribution are you talking about, SnakeMan?
"MODERN" ASTRONOMY CAUGHT DOCTORING PICTURES
The Chandra X-ray Observatory has put out a press release photograph that is doctored, yes, faked.
And Harvard is proud of their deceit.
Whoa, Anaconda -- you've made some pretty stiff charges before, but to charge Harvard, that ivory tower of academic respectability as deceitful -- you must be out of your mind...
Not at all really.
Here is the press release from the Chandra X-ray Observatory.
The picture in the press release has been doctored, faked.
No better than a picture of the Loch Ness Monster, I'm afraid.
Whatever does Anaconda mean?
Link to the press release and look at the picture, see the central area of pink and the two side areas of blue. The pink is where x-rays were detected, the blue is were...nothing was detected, but the Chandra people are "infering" the blue is "dark" matter.
That's right the blue WAS NOT detected.
As the press release in the fith pragraph states: "...the team was able to infer the distribution of the total mass (colored in blue) -- dark and..."
This is intellectual dishonesty at it's highest.
Now, it's okay to doctor photographs.
Especially if that will help carry scientifically dubious so-called "dark" matter.
Nothing was detected. Blue was painted in.
That's dishonest.
It's clear "modern" astronomy wants to create an echo chamber effect where they can claim "dark" matter has been discovered.
It's disgusting.
Read the press release, it's quite clear what the intent is behind the press release.
For another take on the intellectual fraud going down at Harvard (one of the authors is from Stanford), check this link.
Tom,
"Have you ever heard of the Dodo bird or the Passenger Pigeon?"
Not mass extinctions.
"As usual, what you say the URL says is NOT what it says."
What did I say the URL says that it doesn't say?
"Nowhere in the abstract does it say that all mass extinctions are caused by asteroid impacts."
So why do you think it says that?
@ Tom Marking:
Does OilIsMastery say anywhere in the original post that ALL mass extinctions are caused by meteorites or comets?
OilIsMastery does not.
Yet, in your first comment you imply that OilIsMastery thinks all mass extinctions are from meteorites or comets?
That's called a false attribution.
Also, you imply that OilIsMastery doesn't believe there have been extinctions of large animals at the hands of Man.
Again, he didn't write that in the post and I don't recall him writing that anywhere else.
Marking, that's called a false atribution.
And, yes, you are smart enough to know that.
Please, it diminishes your credibility when you engage in such behavior.
@Anaconda "Does OilIsMastery say anywhere in the original post that ALL mass extinctions are caused by meteorites or comets?"
O.K. This is getting tedious. Let OIM answer the following 2 questions which will resolve this issue:
1.) Are all mass extinctions caused by asteroid impacts?
2.) Are any extinctions caused by mankind?
Tom,
1.) Are all mass extinctions caused by asteroid impacts?
No.
2.) Are any extinctions caused by mankind?
Possibly, but in this case it's a red herring.
To Tom Marking,
Regarding the P/T extinction and the formation of the Siberian Traps, there is a 500 km diameter circular gravity anomaly in Wilkes Land Antarctica. Ralph von Frese has recently published an article analyzing the gravity field evidence. I do not have a link to the new article but here is a link to an older one:
http://researchnews.osu.edu/archive/erthboom.htm
Is there any other evidence? Maybe:
http://www.sciencemag.org/cgi/content/abstract/302/5649/1388
The interesting thing about the latter article is the meteoric fragments at Graphite Peak are found precisely at the P/T boundary. If the Wilkes Land structure proves to be an astrobleme, it very well may have formed right at the P/T boundary. This would have profound implications for earth sciences. It would be the third dramatic example of impact structures correlating with antipodal volcanism. The fact that the oldest extant ocean floor on the planet has almost exactly the same age... is unlikely to be a coincidence.
Forgive the digression, but regarding the extinction of the Pleistocene megafauna and whether man did the dirty work:
Quoting from Dr Hibben's book, "The Lost Americans" :
"In many places the Alaskan muck blanket is packed with animal bones and debris in trainload lots."
"Within this mass, frozen solid. lie the twisted parts of animals and trees intermingled with lenses of ice and layers of peat and mosses. It looks as though in the middle of some catacystimic catastrophe. . . the whole Alaskan world of living animals and plants was suddenly frozen in mid- motion in a grim charade" (Frank C. Hibben, The Lost Americans, New York; Apollo Editions, 1961. pp. 90, 91).
Mammal Massacre .. Special Thanks to the author of this site for providing Dr. Hibben's account.
"Tendons, ligaments, fragments skin and hair, hooves - all are preserved in the muck. In some cases, portions of animal flesh have been preserved. Bones of mammoths, mastodons, bison, horses, wolves, bears and lions are hopelessly entangled! One author counts 1,766 jaws and 4,838 meta- podials from ONE species of bison in a small area near Fairbanks, Alaska, alone. Archaeologist Hibben saw with his own eyes - and smelled with his own nostrils - the specter of death. North of Fairbanks, Alaska, he saw bulldozers pushing the melting muck into sluice boxes for the extraction of gold. As the dozers' blades scooped up the melting gunk, mammoth tusks and bones "rolled up like shavings before a giant plane." The stench of rotting flesh -tons of it - could be smelled for miles around.
Hibben and his colleagues walked the pits for days. As they followed the bulldozers they discovered perfect bison skulls with horns attached, mammoth skin with long black hair and jumbled masses of bones.
Appalling Death in Alaska
But let Hibben continue his grisly account:
"Mammals there were in abundance, dumped in all attitudes of death. Most of them were pulled apart by some unexplained prehistoric catastrophic disturbance. Legs and torsos and heads and fragments were found together in piles or scattered separately" ((ibid., p.97). Logs, twisted trees, branches and stumps were interlaced with the mammal menagerie. The signs of sudden death were legion.
For example, in the Alaskan muck, stomachs of frozen mammoths have been discovered. These frozen stomach masses contain the leaves and grasses the animals had just eaten before death struck. Seemingly, no animal was spared.
"The young lie with the old, foal with dam and calf with cow. Whole herds of animals were apparently killed together, overcome by some common power" (ibid, p. 170).
Sudden and Unnatural Death
The muck pits of Alaska are filled with evidence of universal and catastrophic death. These animals simply did not perish by any ordinary means. Multiple thousands of animals in their prime were obliterated.
On reviewing the evidence before his eyes, Hibben concluded:
"We have gained from the muck pits of the Yukon Valley a picture of QUICK EXTINCTION. The evidences of violence there are as obvious as in the horror camps of [Nazi] Germany. Such piles of bodies of animals or men simply do not occur by any ordinary means" (ibid, p 170).
end excerpt....
If man did this to those beasts, they must have really pissed him off. :)
@OIM "1.) Are all mass extinctions caused by asteroid impacts? No"
We are in agreement then on that issue.
"2.) Are any extinctions caused by mankind? Possibly"
Only possibly? Are there no clear examples of human-induced extinction of other species? The dodo bird is a clear-cut case.
Just watched the program. I will have more comments manana.
@ diatreme:
Thank you for providing the passages from Dr. Hibben's account.
The account is vivid and pungent in detail.
diatreme, as you stated, this jumble of animal parts didn't happen in the normal course of things.
Something cataclysmic happened.
Strange how Marking seemingly takes up the Uniformitarian banner. It's not conscious, as Marking allows that geology is not his main interest, just the same that's the impression one gets from his comments.
diatreme, thanks, again. The passages of Dr. Hibben you provided add to the evidence from the documentary to make a more complete and compelling picture of what happened 12,900 years ago.
Thanks for following the website and contributing your valuble information at the appropriate time and place.
I watched the NOVA program online last night. A couple of comments I have are these:
1.) I wasn't sure what the explanation for why the "dark mat" layer separating the layers containing the megafauna and the layers where they are gone was dark. Was it because it contained charred vegetation from a vast forest fire induced by the comet impact? Not sure what they were saying concerning that issue.
2.) They said the Iridium signature of the impactor was considerably smaller than the dinosaur killer (Chicxulub). I would have thought they could estimate the volume of the 12.9 kA impactor based on this ratio of Iridium but they never mentioned it. The only estimate of size I heard in the program was from the Sandia National Laboratories (Yay!, my former employer) dude who was a skeptic - I think he mentioned a 1-km diameter impactor but I have no idea where he got that number from. Obviously the size of the impactor makes a great deal of difference in terms of the devastation.
3.) The Greenland ice cores. I find it puzzling that someone like OIM can trumpet a program like this which finds clear evidence of a 12.9 kA impactor in the Greenland ice cores (nanodiamonds, etc.) while at the same time ignoring the lack of evidence in these same Greenland ice cores for the Velikovsky cataclysms of ~1500 BCE and ~750 BCE which should have been much worse than a comet impact. Very curious.
4.) The comet versus asteroid impactor and the comet swarm versus solitary comet ideas mentioned in the program were clearly designed to avoid the obvious question - where is the impact crater? By switching from 2.5 gm/cm^3 asteroid material to 1.0 gm/cm^3 comet material the cratering is less. By switching from a single comet to a swarm of smaller comets the cratering is reduced further. Also, impact onto the continental ice sheet reduces lasting evidence even more. This is all highly plausible but that doesn't mean it happend that way. There was no evidence presented that the impactor had to be a comet rather than an asteroid.
5.) The disappearance of Clovis Man was not highlighted that much in the program. As I've posted before this is highly questionable which raises the question of why Homo sapiens wasn't wiped out along with the megafauna?
6.) The program mentioned that up to 35 species of mammals went extinct. This still does not qualify as a mass extinction since it only represents about 0.6 percent of the total number of mammal species existing today.
@Anaconda "Strange how Marking seemingly takes up the Uniformitarian banner. It's not conscious, as Marking allows that geology is not his main interest, just the same that's the impression one gets from his comments."
Sounds like a false attribution to me. Where did I ever support uniformitarianism?
It's interesting that the megafauna species in South America went extinct at roughly the same time as their North American brethren. What explains that? They were thousands of miles away from the impact zone in North America.
http://news.nationalgeographic.com/news/2005/
08/0810_050810_iceage.html
"Until about 11,000 years ago, at least 19 different sloth species lived in North and South America in a variety of ecosystems. Only a few small, tree-dwelling sloth species survive today.
Steadman and his colleagues argue that if ecosystem shifts resulting from climate change caused the sloths' demise, then all extinctions—on both islands and the mainland—should have taken place at the same time, as the last Ice Age ended between 15,000 to 9,000 years ago.
Radiocarbon dates of bones, dung, and other tissue of extinct sloths place their last appearance in North America at around 11,000 years ago and at about 10,500 years ago in South America, Steadman says.
But on the islands of Cuba and Hispaniola—shared today by modern-day Haiti and the Dominican Republic—sloths survived until about 4,400 years ago.
Their subsequent extinction coincided exactly with the arrival of the first humans on the islands, Steadman says.
"What [this study] shows us is that there's this great big suggestive pattern that we find: Wherever human beings first appear all around the world, these large mammals pretty quickly become extinct," said Gary Haynes, an archaeologist at the University of Nevada at Reno, who was not involved in the study."
@diatreme "Regarding the P/T extinction and the formation of the Siberian Traps, there is a 500 km diameter circular gravity anomaly in Wilkes Land Antarctica."
Thanks for the URLs. BTW, blogspot clobbered your 2nd URL. You'll have to separate it into 2 lines. As I understand the article the Antarctic mascon is only roughly dated to ~250 million years ago so it either may or may not relate to the Permian/Triassic mass extinction. Either way, it must have been a significant event in geological history.
"It would be the third dramatic example of impact structures correlating with antipodal volcanism."
I was aware of the Chicxulub - Deccan Traps concordance. What is the 3rd example?
"In many places the Alaskan muck blanket is packed with animal bones and debris in trainload lots.
Within this mass, frozen solid. lie the twisted parts of animals and trees intermingled with lenses of ice and layers of peat and mosses. It looks as though in the middle of some catacystimic catastrophe. . . the whole Alaskan world of living animals and plants was suddenly frozen in mid- motion in a grim charade" (Frank C. Hibben, The Lost Americans, New York; Apollo Editions, 1961. pp. 90, 91)."
Are the jumbled remains of various animals what we would expect from a comet impact? I can think of at least one alternative explanation:
http://www.pbs.org/wgbh/nova/transcripts/3211_megafloo.html
How's that for my supposed uniformitarianism? :)
Blogspot got me too:
http://www.pbs.org/wgbh/nova/
transcripts/3211_megafloo.html
@ Tom Marking:
It would be helpful if you would specify what alternative senario you are referring to. And what part of the transcript you are referring to.
I stand by my comment, where I used the words, "seemingly" and "impression" as qualifiers. I also wrote, "It's not conscious..."
And, yes, I remember your comments from prior post topics similar to this one, and there is a marked preference for non-catastrophic explanation exhibited.
In other words: Uniformitarianism.
Mind you, there is nothing wrong with that preference, as long as it doesn't fly in the face of the available scientfic evidence.
@Anaconda "It would be helpful if you would specify what alternative senario you are referring to."
The alternative scenario is this. A glacial dam holding back a glacial lake gave way and a torrent of water was released. All animals in its way would have been carried away. Trees would have been uprooted and carried downstream. Eventually where the flood petered out it would leave a huge debris field containing trees, various animals, boulders, etc., etc. all mixed together. I doubt a comet impact could do that.
http://hugefloods.com/LakeMissoula.html
Lake Missoula, currently the biggest of these glacial dams that burst that we know of, emptied out an entire lake of 500 cubic miles at a rate of 8-10 cubic miles per hour (10 times the combined flow of all the current rivers in the world). It moved more than 50 cubic miles of earth and rock in only a few days. Any megafauna in its way would have perished.
"And, yes, I remember your comments from prior post topics similar to this one, and there is a marked preference for non-catastrophic explanation exhibited."
Really?, maybe in your dreams. What do you think the Lake Missoula flood was if not a catastrophe?
@ Tom Marking:
Point noted and accepted. The Missoula floods are a good example.
Tom,
"The disappearance of Clovis Man was not highlighted that much in the program."
If they highlighted the disappearance you wouldn't be able to blame Clovis Man's extinction on mankind.
@OIM "If they highlighted the disappearance you wouldn't be able to blame Clovis Man's extinction on mankind."
LOL. That's a good joke. But seriously, how does the comet impact theory explain that there was a thriving big-game hunting culture in North America known as the Folsom culture from 10,500 BCE to 9,000 BCE? They hunted bison for a living. I thought the comet impact was supposed to have wiped out humans.
http://archaeology.about.com/od/fterms/qt/folsom.htm
@ Tom Marking:
Obviously, not all Mankind was eliminated from the Western Hemisphere, and I don't think anybody claimed that, nor did anybody claim all animals were exterminated.
Notice the Folsom site is in New Mexico. I note the reference you cited, in turn had a citation listing Oklohoma. And noted these were mobile, specialized hunters.
Who is to say these "Folsom" hunters didn't migrate North, out of Mexico and parts farther South.
Folsom hunters weren't able to exterminate bison, North American hunter/gatherers were likely fairly spread out. In fact, science has little evidence to derive a human population estimate of Clovis hunters or Folsom hunters in North America, is that right?
Perhaps, bison ranged farther South and migrated North in the wake of a comet/meteorite impact.
You still haven't addressed the nano-diamond evidence, which was the evidence the NOVA documentary placed the most emphasis on.
Regarding islands, it must be remembered that sea temperature moderates average climate on islands, so it would not be surprising that isolated island populations would survive as opposed to continental populations. And doesn't that also possibly work against your contention because if Man was on those islands, it apparently took much longer in a limited geography to cause mega fauna extinction.
If Man is the primary cause of the mega fauna demise, as you suggest, then wouldn't island populations of mega fauna be the first to go extinct (assuming humans reached the islands) because of the severely restricted territory?
Marking states:
"The Greenland ice cores. I find it puzzling that someone like OIM can trumpet a program like this which finds clear evidence of a 12.9 kA impactor in the Greenland ice cores (nanodiamonds, etc.) while at the same time ignoring the lack of evidence in these same Greenland ice cores for the Velikovsky cataclysms of ~1500 BCE and ~750 BCE which should have been much worse than a comet impact. Very curious."
This is a deflection -- it's really beside the point that OilIsMastery supports the Velikovskian contention of cataclysms of ~ 1599 B.C. and ~750 B.C. The point is the nano-diamonds and their identifiers as impact/extraterrestial origin were detected in the Greenland ice sheet, isn't it?
And as I pointed out, above, you never address that specific scientific finding.
Do I correctly assume then that you don't deny an impacter of some sort fell 12,900 years ago?
And if so, what role do you assign to the impacter in any possible senarios you would have the readers consider?
Your mission should you decide to accept it, is to construct an alternative senario that takes into account all the available evidence.
@Anaconda "Notice the Folsom site is in New Mexico. I note the reference you cited, in turn had a citation listing Oklohoma."
Last time I checked both New Mexico and Oklahoma were in North America. The NOVA program stated that the comet impact was somewhere in North America. So yes, either New Mexico or Oklahoma could have been ground zero.
"Who is to say these "Folsom" hunters didn't migrate North, out of Mexico and parts farther South."
Or who is to say the Folsom hunters weren't the direct descendants of the Clovis hunters? Without more evidence it could go either way.
"Folsom hunters weren't able to exterminate bison, North American hunter/gatherers were likely fairly spread out. In fact, science has little evidence to derive a human population estimate of Clovis hunters or Folsom hunters in North America, is that right?"
It's true that the bison did not go extinct either through human predation or being in the kill zone of the comet.
"You still haven't addressed the nano-diamond evidence, which was the evidence the NOVA documentary placed the most emphasis on."
Well, the NOVA program just assumed that nanodiamonds can only be formed via extraterrestrial impacts. As far as I recall, no evidence was presented for that position. It would be nice to see nanodiamonds associated with known impact craters such as Meteor Crater in Arizona, but the NOVA show didn't present any such evidence. I'm not a geologist. It certainly sounds plausible which is about all I can say at the moment.
IMHO, there is much better evidence for the 4,800 kA asteroid impact in the Indian Ocean. We have an actual impact crater (Burkle crater) at the bottom of the Indian Ocean.
"Regarding islands, it must be remembered that sea temperature moderates average climate on islands, so it would not be surprising that isolated island populations would survive as opposed to continental populations. And doesn't that also possibly work against your contention because if Man was on those islands, it apparently took much longer in a limited geography to cause mega fauna extinction."
You misread the article. The giant sloth went extinct on Hispaniola roughly 4,000 years ago. That is roughly the same time as the first evidence of human habitation. So there is a correlation in time between the arrival of man and the extinction of the giant sloth. The same holds true for the Moa in New Zealand, the giant lemur in Madagascar, etc., etc.
"If Man is the primary cause of the mega fauna demise, as you suggest, then wouldn't island populations of mega fauna be the first to go extinct (assuming humans reached the islands) because of the severely restricted territory?"
No, the islands are isolated. The earliest humans were not sea faring. As soon as the humans event watercraft and reach these islands the megafauna is doomed.
"This is a deflection -- it's really beside the point that OilIsMastery supports the Velikovskian contention of cataclysms of ~ 1599 B.C. and ~750 B.C. The point is the nano-diamonds and their identifiers as impact/extraterrestial origin were detected in the Greenland ice sheet, isn't it?"
No, it's not a side point. If you are a committed Velikovskian (which I know you are not) you can not use Greenland ice core data of any sort because you have already rejected Greenland ice core data because it doesn't show the Velikovskian cataclysms.
"Do I correctly assume then that you don't deny an impacter of some sort fell 12,900 years ago? And if so, what role do you assign to the impacter in any possible senarios you would have the readers consider?"
No, I don't deny that there was an asteroid/comet impact in North America roughly 12,900 years ago. I accept the Greenland ice core data. As to what role it played it all depends on what size it was and where it landed exactly. Neither of those points were addressed by the NOVA program.
I'll present evidence on what a 1-kilometer wide comet would do if it impacted the earth.
Program to compute effects from an asteroid or comet impact
Target planet or moon = Earth
Diameter of the impactor = 1.0 kilometers
Density of the impactor = 1.50 gm/cm^3
Initial velocity of the impactor = 30.00 km/sec
Initial elevation angle of the impactor above horizon = 45.0 degrees
Density of the target surface = 2.50 gm/cm^3
Land strike
Distance of observer from surface impact point = 500.0 km
Gravitational acceleration at surface of planet = 9.81 m/s^2
Minimum velocity of an impactor = 11.2 km/sec
Maximum velocity of an impactor = 71.9 km/sec
Atmospheric pressure at surface = 1.013E5 pascals
Atmospheric density at surface = 1.226E-3 gm/cm^3
Surface temperature = 15.0 deg C
Atmospheric scale height (isothermal) = 8.43 km
Initial kinetic energy of impactor in outer space = 3.53E20 joules
= 8.45E4 Megatons TNT
An impact of this size occurs once every 4.32E5 years
Atmospheric entry:
Velocity of the impactor at the surface = 29.59 km/sec
Elevation angle of the impactor at the surface = 45.1 degrees
Amount of energy dissipated in the atmosphere = 2.71%
Duration of the atmospheric entry = 3.98 sec
Kinetic energy of impactor at the surface = 3.44E20 joules
= 8.22E4 Megatons TNT
= 7.82 Richter scale
Cratering effects:
Width of transient crater at the surface = 1.07E1 km
Depth of transient crater at the surface = 3.79E0 km
Volume of transient crater at the surface = 1.71E2 km^3
Width of final crater at the surface = 1.47E1 km
Depth of final crater at the surface = 8.95E-1 km
Volume of final crater at the surface = 7.57E1 km^3
Thermal effects:
The fireball cannot be seen by the observer
Radius of the fireball generated by the impact = 1.40E1 km
Maximum distance that fireball can be seen = 4.22E2 km
Time for thermal radiation to reach its peak = 4.74E-1 sec
Duration of the thermal radiation = 1.82E2 sec
Distance out to which 1st degree burns happen = 288.0 km
Distance out to which 2nd degree burns happen = 243.0 km
Distance out to which 3rd degree burns happen = 205.0 km
Seismic effects:
Magnitude of ground shaking experienced by observer = 4.26 Richter scale
Time for the seismic waves to reach the observer = 1.00E2 sec
Observer's experience: Shaking felt by nearly everyone; some dishes and windows are broken
Distance out to which everyone feels ground shaking = 398.0 km
Distance out to which buildings partially collapse = 85.0 km
Distance out to which most private houses collapse = 24.0 km
Distance out to which most buildings collapse = 0.0 km
Air blast effects:
Peak overpressure of blast wave at the observer point = 7.09E3 pascals
= 7.00E-2 atm
Time for the air blast wave to reach the observer = 1.47E3 sec
Peak wind velocity at the observer point = 1.65E1 m/s
= 5.95E1 km/hr
Observer's experience: Glass windows shatter
Distance out to which glass windows shatter = 510.0 km
Distance out to which wood-framed houses collapse = 219.0 km
Distance out to which steel-framed buildings collapse = 68.0 km
Distance out to which highway girder bridges collapse = 58.0 km
Estimated human death toll:
Estimated non-tsunami death radius = 219.0 km
Population density = Australia avg : number of deaths = 3.92E5
Population density = Russia avg : number of deaths = 1.27E6
Population density = USA avg : number of deaths = 4.67E6
Population density = World avg : number of deaths = 6.73E6
Population density = China avg : number of deaths = 2.08E7
Population density = UK avg : number of deaths = 3.71E7
Population density = India avg : number of deaths = 5.06E7
Population density = Bangladesh avg: number of deaths = 1.57E8
Percent of deaths caused by cratering effects = 0.06%
Percent of deaths caused by thermal effects = 46.38%
Percent of deaths caused by seismic effects = 0.64%
Percent of deaths caused by air blast effects = 52.93%
So wrote a Java program to compute the effects of a 1-kilometer diameter comet strike on land. The density of the comet is assumed to be 1.5 grams per cubic centimeter. It's impact velocity is assumed to be 30 kilometers per second at an angle of 45 degrees above the horizontal.
An impactor of this size is expected to hit the earth once every 430,000 years. Thus, the odds of something this size hitting the earth during the last 12,900 years is 32 to 1 against. The comet's atmospheric entry lasts only 4 seconds and it looses less than 3 percent of its kinetic energy passing through the atmosphere.
It hits the surface with an energy of 82,000 megatons of TNT (more than 1,500 times more energy than the greatest nuclear weapon ever exploded). It creates a crater in the groun 14.7 km wide by 0.895 km deep gouging out 75 cubic kilometers of rock.
It generates a fireball which can be seen out to a distance of 420 kilometers. People caught out in the open will experience third degree burns out to a distance of 205 kilometers. An observer at a distance of 500 kilometers will experience a mild earthquake of magnitude 4.2. If it happened today the blast effects would cause glass windows to shatter out to a distance of 510 kilometers. Wood-framed houses would collapse out to a distance of 220 kilometers. The death toll might go anywhere from 400,000 people in sparsely populated Australia to 50 million people in densely populated India. The death radius would be something like 200 kilometers. Every living human, dog, horse, etc. within that radius would perish.
Now take this event back to 12,900 years ago. The human death toll would have been much lower than 400,000 people due to the very sparse population. Would death and destruction within a radius of 200 kilometers be enough to cause 35 species to go extinct? I somehow doubt it, at least not from the direct effects.
So a 1-kilometer wide comet does not seem big enough to accomplish the extinction. Of course, making the impactor bigger makes the odds of it happening during the last 12,900 years that much smaller.
So yes, there are grounds for skepticism concerning the linkage of this event to the extinction of the megafauna.
@TM "Would death and destruction within a radius of 200 kilometers be enough to cause 35 species to go extinct?"
A kill radius of 219 km is an area of 151,000 square kilometers. North America has an area of 24,700,000 square kilometers. Thus, assuming equal area distributions of the megafauna if you are a typical Woolly Mammoth or Saber-toothed Tiger you have a 0.6 percent chance of being in the kill zone of this 1-kilometer comet.
@ Tom Marking:
I can appreciate the detail, but it's a computer program.
What matters is the actual evidence that scientists have to work with.
By your own admission, the human population would be sparse, therefore it can easily be questioned whether enough hunter/gatherers were on the North American continent to effectuate an extinction of that magnitude.
Also, totally unadressed is the effect on climate that an impact would have and apparently there was a rapid climate shift -- whether this was caused by the impact is unknown.
What you have done, Marking, is avoid the evidence at hand and attempted to set up your own evidence.
Wrong!
But totally in keeping with "modern" astronomy's tendency to create their own "evidence" to suit their mathematical equations.
I got news for you Marking: That doesn't wash outside of "modern" astronomy.
You have to deal with the observations & measurements as found in the geological record.
Again, you are twisting out of a direct question, which is so common from you.
Do you dispute the proposition that an impact occured 12,900 years ago?
If so, what evidenciary evidence to you rely on.
Computer programs are not evidence in geology.
If you don't dispute an impact occured then how does that play into an alternative senario considering all the evidence.
So far, you have declined your mission, you have not provided and alternative senario.
It is probably too early to firmly conclude that the end-Clovis event was induced by an impact. New methods of analyzing the physical evidence appear regularly and there is no need to rush to a conclusion.
The one thing that arouses my curiosity is the so-called Black mat layer. I have seen and handled the coal layer that sits above the K/T boundary layer in southern Colorado and would like to do the same with that end-Clovis layer.
@Anaconda "Again, you are twisting out of a direct question, which is so common from you. Do you dispute the proposition that an impact occured 12,900 years ago?"
Anaconda, are you having trouble with your reading comprehension yet again? I've already answered that question. Please reread my last few posts.
@ Tom Marking:
I stand corrected, you did answer in the affimative on the impact question. I missed that response -- my bad.
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