Posted on 10/17/2005 8:57:32 AM PDT by Fzob
Sept. 28, 2005— A supernova blast 41,000 years ago started a deadly chain of events that led to the extinction of mammoths and other animals in North America, according to two scientists.
If their supernova theory gains acceptance, it could explain why dozens of species on the continent became extinct 13,000 years ago.
Mammoths and mastodons, both relatives of today's elephants, mysteriously died out then, as did giant ground sloths, a large-horned bison, a huge species of armadillo, saber-toothed cats, and many other animals and plants.
Richard Firestone, a nuclear scientist at the U.S. Department of Energy's Lawrence Berkeley National Laboratory, who formulated the theory with geologist Allen West, told Discovery News that a key piece of evidence for the supernova is a set of 34,000-year-old mammoth tusks riddled with tiny craters.
The researchers believe that in the sequence of events following the supernova, first, the iron-rich grains emitted from the explosion shot into the tusks. Whatever caused the craters had to have been traveling around 6,214 miles per second, and no other natural phenomenon explains the damage, they said.
They think the supernova exploded 250 light-years away from Earth, which would account for the 7,000-year delay before the tusk grain pelting. It would have taken that long for the supernova materials to have showered to Earth.
Then, 21,000 years after that event, the researchers believe a comet-like formation from the supernova's debris blew over North America and wreaked havoc.
Firestone said they think the formation created superheated hurricanal winds in the atmosphere that rolled across North America at 400 kilometers per hour (about 249 mph).
"The comet (-like event) was followed by a barrage of hot particles. If that didn't kill all of the large animals, then the immediate climate changes must have," said Firestone.
Firestone said smaller animals could have sought shelter more readily, by going into caves or underground.
The findings were presented at last weekend's "World of Elephants" international conference in Hot Springs, S.D.
In addition to the tusk evidence, the scientists said arrowheads from North America's prehistoric Clovis culture, which went extinct around 13,500-13,000 years ago, Icelandic marine sediment, as well as sediment from nine 13,000-year-old sites in North America, contain higher-than-normal amounts of radiation in the form of potassium-40 levels.
Potassium-40 is a radioactive isotope, meaning a molecule that emits radiation.
Magnetic particles also were unearthed at the sites. Analysis of these particles revealed they are rich in titanium, iron, manganese, vanadium, rare-earth elements, thorium and uranium.
These elements all are common in moon rocks and lunar meteorites, so the researchers think the materials provide additional evidence that North America was bombarded 13,000 years ago by material originating from space.
Luann Becker, a University of California at Santa Barbara geologist, told Discovery News she was not surprised by the new supernova theory, since extinction events have been linked to similar comet or asteroid impacts before.
"What is exciting about Dr. Firestone's theory is that it can be easily tested," Becker said, and indicated she hopes future research will yield additional clues from North American and other sediment layers.
LOL! Look, we're not talking about million year old monkey bones here. C-14 dating is generally reliable for anything less than 50,000 years old. I say "generally" because it does vary slightly based on surrounding environmental conditions, and older samples can be off by a couple thousand years (a whisker by the timescales we're discussing). Still, sometimes flukes do happen, which is why generalized statements like "the humans wiped out the sloths" have to be backed up by numerous datings from geographically diverse sites.
In this case, the fossil record is heavy enough to corroborate this theory and offer useful averages. We can tell, for instance, that North America wasn't widely populated by humans 50,000 years ago because the bones dug up so far are almost exclusively newer than that (yes, I know about the flukes, but those could be misreads or even examples of very early explorers). We also know that sloth bones used to be common. We know that the C-14 shows that human remains start showing up around point X, and that sloth remains stop showing up shortly afterward.
It's really not important whether Date X happened 20,000 years ago or 15,000 years ago, but simply that the dating techniques show that the two sets of events happened at the same time.
So as the world turned, it was being hit with a hail storm of death and only those in caves or small enough to miss getting hit survived.
Bush's fault for sure!
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alas:
Supernova Storm Wiped Out Mammoths?
Discovery News | 09/28/05 | Jennifer Viegas
Posted on 10/04/2005 11:47:27 PM PDT by planetesimal
http://www.freerepublic.com/focus/f-news/1496844/posts
related:
Supernova debris found on Earth
NEWS@NATURE.COM | 02 November 2004 | Mark Peplow
Posted on 11/24/2004 1:22:08 PM PST by Phsstpok
http://www.freerepublic.com/focus/f-news/1287848/posts
Mammoth remains unearthed in California (SoCal - Moorpark)
Monterey Herald | 4/7/05 | AP
Posted on 04/07/2005 9:28:36 PM PDT by NormsRevenge
http://www.freerepublic.com/focus/f-news/1379623/posts
Mammoth, Tusks Found by Los Angeles-Area Builders
Reuters | April 8, 2005
Posted on 04/10/2005 5:48:12 AM PDT by billorites
http://www.freerepublic.com/focus/f-news/1380816/posts
and from the "Just when you thought it was safe to go back to the Stone Age" dep't:
Frozen Woolly Mammoth Arrives in Japan
yahoo news | 11/18/04 | some fool from AP
Posted on 11/19/2004 7:35:37 PM PST by satchmodog9
http://www.freerepublic.com/focus/f-news/1284407/posts
Scientists Aim to Revive the Woolly Mammoth
live Science | 11 Apr 05 | Bill Christensen
Posted on 04/18/2005 8:08:56 AM PDT by Drew68
http://www.freerepublic.com/focus/f-news/1385950/posts
Russians have Cloned the Woolly Mammoth
MIT Technology Review | May 17, 2005 | Dr. E.M. Bécile
Posted on 05/18/2005 2:57:52 PM PDT by Boondock_Saint
http://www.freerepublic.com/focus/f-chat/1405928/posts
Dead Wooly Mammoth Ping
Uh, well, er ah, they evidently haven't named the star......but the Truth is Our There *yeah, right*
With this story, methinks Art Bell will find the origin of all those aliens that have been visiting.
I miss the giant ground sloths the most, I think.
God was definately NOT happy with these giants and rid the world of them for man. Thank God huh? LOL
Why did the humans kill only animals that weighed over 250 pounds, on average? There may be an explanation but as the article says:
"What is exciting about Dr. Firestone's theory is that it can be easily tested," Becker said, and indicated she hopes future research will yield additional clues from North American and other sediment layers."
I'll wait for the research.
I've gone through the same thought process although I'm the opposite of a Rousseau fan. I keep running aground on the problem of why large "easy" animals were hunted to extinction only in certain parts of the world. The "pissed-off" elephant theory doesn't reverberate with me: I presume mastadons got "pissed-off" too.
Maybe Clovis hunters were simply more efficient as killers than hunters in other parts of the world like Africa and India, etc., where large mammals survived. But that doesn't seem to fit with the evidence, particularly in places like Australia. The theory that massive human-set fires were used in Oz to destroy the large mammals has been floated but I have nagging questions about that as well. More modern Amerinds used fire in their hunting but at the time of Lewis and Clark (see Journals) there were still plenty of buffalo left.
What's wrong with considering whatever evidence Firestone has to offer?
I did, thanks.
Nothing at all, but as a confirmed sceptic, I'm a fan of Occam's Razor.
Occam's shaves pretty closely, I agree. But I don't think it's 100% accurate. Nothing wrong with looking at new evidence IMO. It can be sent to the junk heap quickly if it doesn't prove up.
My theory is that our ancestors combined the atlatl (100 yard range and good penetration but poor accuracy) with Clovis points (grooves hold the poison) and a simple poison like nicotine or aconite (from Monkshood flowers). Large herd critters like mammoth would be easily dispatched from a safe range and the tribe would feast for a week. Smaller, harder-to-hunt critters like elk and deer were spared.
We're dealing with the last 50,000 years, so most of the dating is probably Carbon-14 dating.
Where do you see the inaccuracies in this method? It seems to work fine for me.
"Don't tell me,...the next World of Elephants international conference will be held in ....Tuscany?"
Of course in Alabama, the Tuscaloosa.
I won't tell you what I think.
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