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Comet May Have Doomed Mammoths
Red Orbit ^ | 5-26-07 | Betsy Mason

Posted on 05/26/2007 6:12:53 AM PDT by Renfield

mammoth some 12,900 years ago. A team of two dozen scientists say the culprit was likely a comet that exploded in the atmosphere above North America.

The explosions sent a heat and shock wave across the continent, pelted the ground with a layer of telltale debris, ignited massive wildfires and triggered a major cooling of the climate, said nuclear analytic chemist Richard Firestone of Lawrence Berkeley Laboratory, one of the scientists who presented the controversial new theory Thursday at a conference of the American Geophysical Union in Acapulco.

At least 15 species, mostly large mammals including mammoths, mastadons, giant ground sloths, camels and horses, were wiped out about the same time. Firestone and his colleagues think some may have been killed by the explosions, and the rest died off after fires burned the vegetation they depended on.

"It seems awfully coincidental that the mammoths died at exactly the same moment where we find this impact layer," said Allen West, a member of the team from GeoScience consulting in Dewey, Ariz.

The scientists are bracing themselves for fiery reaction to their theory.

The extinctions were already a hotly debated event with scientists split between two theories. The leading theory is that man hunted the animals into extinction soon after arriving in North America, but some scientists think climate upheaval as the earth warmed up from the last ice age was the killer. Others think it was more of a one-two punch with climate change weakening the animal populations and hunters delivering the final blow.

But the impact theory has the advantage that it would explain why the Clovis hunting culture disappeared along with the animals, said archeologist Douglas Kennett of the University of Oregon.

For 300 years, Clovis people hunted mammoths and other animals with distinctive spear heads with fluted ends known as Clovis points.

The team visited archaeological sites containing Clovis points across North America and collected samples of the sediment that covered the last signs of Clovis people and the last mammoth bones.

They found many distinctive signs of an extraterrestrial impact, including rounded magnetic grains that formed when pieces of the comet were thrown back into space after the explosion and then melted into round grains as they re-entered the atmosphere.

They also found high levels of iridium and titanium, a special form of carbon molecules known as fullerenes that had helium atoms trapped inside, and microscopic diamonds called nanodiamonds. They also found strange rounded carbon grains and glass-like carbon that looks like hardened black taffy. Lots of soot and charcoal are evidence of the ensuing wildfires.

"We really have found the mother lode of impact material," Firestone said.

Above this layer of strange sediment there are no signs of mammoths or many of the other large mammal species of the day, or of the distinctive Clovis points. At many of the sites there is a gap in evidence of humans for several hundred years before new types of spear heads show up.

Just like the mammoths, many of the Clovis people could have been killed by the comet. Those who lived would have struggled to survive once many of the animals they hunted died. The remaining people may have delivered the final blow to the last of the large mammals. These people made it through, and slowly the human population rebounded.

Post-Clovis people were more culturally diverse, as reflected by an array of different spear heads, Kennett said. "This may suggest population fragmentation."

The survivors could have been separated into smaller groups across the continent that developed differing cultural traditions and spear head designs.

The explosion may also be the key to an enigmatic episode of cooler climate, known as the Younger Dryas, that began about the same time and lasted about 1,000 years. The earth had been steadily warming up after the last ice age due to cyclical changes in the planet's orbit that brought it slightly closer to the sun. Then suddenly, the climate started cooling for no obvious reason at a time when it should have still been warming up.

Previously, the leading theory for the cause of the cooling was that as the ice sheet that covered most of North America retracted to the north, the meltwater that had been flowing to the south switched to the east as eastern river drainages were uncovered. This surge of fresh water into the Atlantic caused a change in the ocean circulation that shut down a northward flow of warm water that had acted as a heater for the northern hemisphere.

"Earth was warming and then suddenly went back into cooling for 1,000 years," Firestone said.

The evidence for a change in ocean circulation fits with the comet theory as well, said paleoceanographer James Kennett of UC Santa Barbara. He argues that the massive explosion above the North American ice sheet would have caused a huge amount of melting and destabilization around the edges of the ice that would have sent a torrent of fresh water into the Atlantic Ocean that could have affected circulation.

The new theory will undoubtedly come under fire from several directions, including the scientists that study the North American extinctions as well as from those who study extraterrestrial impacts.

Princeton University paleontologist Gerta Keller studies impacts and is skeptical that the explosion 12,900 years ago was big enough to have had such a big effect on climate and animals.

Keller has found evidence that much larger impacts did not cause any major extinctions. According to her, even the asteroid that left a massive crater on the Yucatan Peninsula known as Chicxulub and is thought to have killed off the dinosaurs did not actually cause their extinction.

"If Chicxulub didn't cause extinctions, then how could something this piddling cause these extinctions, and how could it have changed climate for 1,400 years?" she asked.


TOPICS: Miscellaneous
KEYWORDS: catastrophism; clovis; clovisimpact; comet; comets; extinction; gertakeller; godsgravesglyphs; impact; paleontology

1 posted on 05/26/2007 6:12:55 AM PDT by Renfield
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To: blam; SunkenCiv

Ping


2 posted on 05/26/2007 6:13:24 AM PDT by Renfield
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To: Renfield

And I thought it was global warming cause by climate change - got all the buzz phrases in one sentence.


3 posted on 05/26/2007 6:14:22 AM PDT by WorkerbeeCitizen (I Relieve Myself In Islam's General Direction While I Deny Global Warming.)
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To: Renfield
At least 15 species, mostly large mammals including mammoths, mastodons, giant ground sloths, camels and horses, were wiped out about the same time.

The species Albertus Goreasaurus was wiped out by this catastrophe too, but its descendants live to this day.

4 posted on 05/26/2007 6:19:13 AM PDT by rickmichaels (God Bless America, Land That I Love)
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To: Renfield

Yawn. More worthless speculation masquerading a science. Gotta publish, gotta publish.... even if it’s pure conjecture.

I can make stuff up too. Mine is more interesting. How’s this? The mammoths were wiped out by.... Bush!!


5 posted on 05/26/2007 6:21:41 AM PDT by Seruzawa (Attila the Hun... wasn't he a liberal?)
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To: WorkerbeeCitizen
And I thought it was global warming cause by climate change, causing El Nino and other weather anomolies putting women and minorities at risk.

A minor correction, and I'm sure we're still missing a few more buzzwords. :)

6 posted on 05/26/2007 6:38:12 AM PDT by theDentist (Qwerty ergo typo : I type, therefore I misspelll.)
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To: WorkerbeeCitizen
And I thought it was global warming cause by climate change - got all the buzz phrases in one sentence.

Damn, beat me to it by a nano second!

7 posted on 05/26/2007 6:49:51 AM PDT by org.whodat (What's the difference between a Democrat and a republican????)
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To: theDentist
:)

Of course the Earth priests and priestesses will never read a piece of research like this.

8 posted on 05/26/2007 6:55:19 AM PDT by WorkerbeeCitizen (I Relieve Myself In Islam's General Direction While I Deny Global Warming.)
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To: Renfield
Sorry for stepping on this thread ... but I could not resist!

The extinctions were already a hotly debated event with political scientists split between two theories. The leading theory is that illegal immigrants drove the U.S. Republic into extinction soon after arriving in North America, but some political scientists think political upheaval as the U.S. warmed up from the 2007 riots was the killer. Others think it was more of a one-two punch with illegal immigration weakening the U.S. population and Senators delivering the final blow.

Again I apologize.

9 posted on 05/26/2007 7:41:50 AM PDT by Red_Devil 232 (VietVet - USMC All Ready On The Right? All Ready On The Left? All Ready On The Firing Line!)
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To: Renfield
At least 15 species, mostly large mammals including mammoths, mastadons, giant ground sloths, camels and horses, were wiped out about the same time.

Guess that's why we don't have horses, camels and mastadons (whatever those are) today.

10 posted on 05/26/2007 7:49:01 AM PDT by sionnsar (trad-anglican.faithweb.com |Iran Azadi| 5yst3m 0wn3d - it's N0t Y0ur5 (SONY) | UN: Useless Nations)
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Did comet start deadly cold snap?
Canada.com | Monday, May 14, 2007 | Margaret Munro
Posted on 05/16/2007 6:00:33 PM EDT by Mike Darancette
http://www.freerepublic.com/focus/f-news/1834769/posts

Diamonds tell tale of comet that killed off the cavemen
Guardian | 5-20-07 | Robin McKie
Posted on 05/20/2007 7:50:33 PM EDT by Renfield
http://www.freerepublic.com/focus/f-news/1836898/posts

Catastrophic Comet Chilled and Killed Ice Age Beasts (and Clovis people)
Live Science | 05/21/07 | Jeanna Bryner
Posted on 05/22/2007 1:16:48 AM EDT by TigerLikesRooster
http://www.freerepublic.com/focus/f-news/1837610/posts

Oregon Researchers Involved In New Clovis-Age Impact Theory (More)
Eureka Alert
Posted on 05/23/2007 5:30:19 PM EDT by blam
http://www.freerepublic.com/focus/f-news/1838660/posts


11 posted on 05/26/2007 8:00:41 AM PDT by SunkenCiv (Time heals all wounds, particularly when they're not yours. Profile updated May 22, 2007.)
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Keller has found evidence that much larger impacts did not cause any major extinctions. According to her, even the asteroid that left a massive crater on the Yucatan Peninsula known as Chicxulub and is thought to have killed off the dinosaurs did not actually cause their extinction.
Keller is full of it.
12 posted on 05/26/2007 8:01:20 AM PDT by SunkenCiv (Time heals all wounds, particularly when they're not yours. Profile updated May 22, 2007.)
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The Cycle of Cosmic Catastrophes: Flood, Fire, and Famine in the History of Civilization The Cycle of Cosmic Catastrophes:
Flood, Fire, and Famine in
the History of Civilization

by Richard Firestone,
Allen West,
Simon Warwick-Smith


13 posted on 05/26/2007 8:01:42 AM PDT by SunkenCiv (Time heals all wounds, particularly when they're not yours. Profile updated May 22, 2007.)
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Catastrophism
· join · view topics · view or post blog · bookmark · post new topic ·

14 posted on 05/26/2007 8:01:57 AM PDT by SunkenCiv (Time heals all wounds, particularly when they're not yours. Profile updated May 22, 2007.)
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To: Renfield
Thanks Renfield. No ping, just adding to the catalog.

To all -- please ping me to other topics which are appropriate for the GGG list. Thanks.
Please FREEPMAIL me if you want on or off the
"Gods, Graves, Glyphs" PING list or GGG weekly digest
-- Archaeology/Anthropology/Ancient Cultures/Artifacts/Antiquities, etc.
Gods, Graves, Glyphs (alpha order)

15 posted on 05/26/2007 8:02:23 AM PDT by SunkenCiv (Time heals all wounds, particularly when they're not yours. Profile updated May 22, 2007.)
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To: sionnsar
mastadons (whatever those are)

Furry elephants.

16 posted on 05/26/2007 8:12:57 AM PDT by PAR35
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To: Renfield

We’re gonna’ have to find Cheney’s Commet-O-Matic Machine and destroy it before the Republicans start using that with their Hurricane-O-Matic Machine!

>:-(


17 posted on 05/26/2007 8:15:07 AM PDT by bannie
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To: Renfield

Mammoths were reported in Canada 400 years ago, and the youngest recovered carcass (Alaska) is about 4000 years old.


18 posted on 05/26/2007 8:15:56 AM PDT by RightWhale (Repeal the Treaty)
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To: Renfield

There may have been horses in America before the Spaniards introduced them. Some Natives have been reported to be riding horses already by then.


19 posted on 05/26/2007 8:18:12 AM PDT by RightWhale (Repeal the Treaty)
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To: Renfield

The extinction seems a little too selective yet widespread to be caused by a single impact event.


20 posted on 05/26/2007 8:43:17 AM PDT by Mike Darancette (Democrat Happens!)
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To: Renfield

YEC INTREP


21 posted on 05/26/2007 8:55:36 AM PDT by LiteKeeper (Beware the secularization of America; the Islamization of Eurabia)
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To: Seruzawa
More worthless speculation masquerading a science.

Worthless speculation? Did you read the article? Did you notice the part about what they found in soils overlying the Clovis layers?

22 posted on 05/26/2007 9:06:59 AM PDT by Coyoteman (Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.)
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To: Renfield; blam; SunkenCiv
"Chicxulub ....(snip) ....did not actually cause their extinction" (dinosaurs).

What's up with this? I thought this was a done deal.

23 posted on 05/26/2007 9:07:00 AM PDT by jpsb
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To: Coyoteman
Going to play your flute again? LOL.
24 posted on 05/26/2007 9:23:14 AM PDT by ASA Vet (Pray for the deliberately ignorant.)
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To: Seruzawa
Yawn. More worthless speculation masquerading a science. Gotta publish, gotta publish.... even if it’s pure conjecture. I can make stuff up too. Mine is more interesting. How’s this? The mammoths were wiped out by.... Bush!!

I have a better theory. These large mamals were so flatulant that a thick layer of methane settled down on the continent depriving them of oxygen, so they all suffocated. How's that for a theory?

25 posted on 05/26/2007 9:31:49 AM PDT by calex59
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To: calex59

Oops, post 25 mamals=mammals.


26 posted on 05/26/2007 9:32:17 AM PDT by calex59
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To: rickmichaels

What about RINOs?


27 posted on 05/26/2007 9:36:36 AM PDT by dvan
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To: Renfield

Comet!
It makes your teeth turn green.

Comet!
It tastes like gasoline.

Comet!
It makes you vomit!

So have some Comet and vomit today!


28 posted on 05/26/2007 9:38:09 AM PDT by dfwgator (The University of Florida - Still Championship U)
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To: Coyoteman
Worthless speculation? Did you read the article?

It would be even better if people actually read the actual original scientific papers with all the documentary evidence.

People seem to be under the impression there's no fieldwork or research for stuff like this, that it's some guy in an office waving his arms.

29 posted on 05/26/2007 10:21:04 AM PDT by Strategerist
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To: Seruzawa
worthless speculation masquerading a science

You are a idiot. The science is the hard data that they recorded and reported, including the coincidence in age of the depostion layers of the cometary remnants that they report. Whether or not this explains the extinction is, of course, an open question, but one that is solveable by others looking for confirmatory or contradictory data.

This is how science is done, my man. These are world-class researchers and it doesn't get any better than this.

Of course there is competition to publish. But, we are conservatives / libertarians who believe that the world is better off when you have free market competition, and that goes for ideas as well as goods. So, we are supposed to chear this stuff.

30 posted on 05/26/2007 10:28:26 AM PDT by AndyJackson
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To: jpsb

Yes, the Debate is Over. ;’) There aren’t any really new objections to mass extinction, merely those who refuse to accept it on a priori grounds.


31 posted on 05/26/2007 11:16:14 AM PDT by SunkenCiv (Time heals all wounds, particularly when they're not yours. Profile updated May 22, 2007.)
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To: Strategerist
It would be even better if people actually read the actual original scientific papers with all the documentary evidence.

People seem to be under the impression there's no fieldwork or research for stuff like this, that it's some guy in an office waving his arms.

This is a good follow-up to the report a few weeks ago by Waters and others about the actual age of Clovis.

Science builds up incrementally, with occasional breakthroughs.

My favorite line of research now is mtDNA and the early coastal migration problem.

32 posted on 05/26/2007 12:59:04 PM PDT by Coyoteman (Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.)
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To: AndyJackson

Yeah whatever, professor.


33 posted on 05/27/2007 10:36:49 AM PDT by Seruzawa (Attila the Hun... wasn't he a liberal?)
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