North America comet theory questioned

Nature ^ | 12 Oct 2009 | Rex Dalton

[BGHater]

No evidence of an extraterrestrial impact 13,000 years ago, studies say.

An independent study has cast more doubt on a controversial theory that a comet exploded over icy North America nearly 13,000 years ago, wiping out the Clovis people and many of the continent's large animals.

Sediments at the San Jon site, in eastern New Mexico, contained very low abundances of magnetic spherules said to be evidence of an impact.Vance Holliday

Archaeologists have examined sediments at seven Clovis-age sites across the United States, and did not find enough magnetic cosmic debris to confirm that an extraterrestrial impact happened at that time, says the report in the Proceedings of the National Academy of Sciences (PNAS)¹. It is the latest of several studies unable to support aspects of the impact hypothesis.

In 2007, a team led by Californian researchers announced a theory² that a comet or asteroid had exploded over the North American ice sheet, creating widespread fire and an atmospheric soot burst followed by a cooling period known as the Younger Dryas. Sometime after this, the Clovis people, sophisticated large-animal hunters known for their spear points, mysteriously disappeared; the team linked their vanishing to the environmental effects of the proposed impact.

Key evidence came in the form of magnetic microspherules discovered in sediments at 25 locations, including eight Clovis-age sites. Richard Firestone, of Lawrence Berkeley National Laboratory in California, and his colleagues argued that the microspherules were remnants of cosmic debris from an explosion.

But in more than 18 months of sedimentary analysis, a team led by Todd Surovell, an archaeologist at the University of Wyoming in Laramie, was unable to detect microspherule peaks. Two of the seven sites the group studied were places where Firestone's team identified spherule peaks.

"I spent hundreds of hours at the microscope examining sediment samples," says Surovell, "and I didn't find any physical evidence to support their theory."

Standing firm

The other team isn't backing down. "Their study doesn't negate our hypothesis," says James Kennett, a palaeoceanographer at the University of California at Santa Barbara and one of Firestone's co-authors. Another co-author, avocational geophysicist Allen West of Prescott, Arizona, says that Surovell's group didn't use the correct technique to extract, identify and quantify the microspherules.

Several other groups have been unable to support important aspects of the comet theory.

In a PNAS article published in February³, Jennifer Marlon, a doctoral geography student at the University of Oregon in Eugene, and her colleagues found no systematic burning of biomass — as would have occurred if continent-wide fires had happened — at the time of the Younger Dryas in pollen and charcoal records at 35 sites. And at the Ecological Society of America meeting in Albuquerque, New Mexico, in August, Jacquelyn Gill, a palaeoecology doctoral student at the University of Wisconsin-Madison, reported finding no evidence of massive burning in sediment cores taken from lake beds in Ohio and Indiana.

Kennett, however, calls these studies "flawed". In August, his team published a report⁴ saying they had found nanometre-sized diamonds, purportedly created during an impact, and soot in sediments dated to the Younger Dryas on Santa Rosa Island, off the coast of California.

More studies of the theory — both critical and supportive — are in the publishing pipelines at other journals.

Surovell's co-author Vance Holliday, an archaeologist at the University of Arizona in Tucson, and his colleagues have an article in press at Current Anthropology that says the archaeological and geochronological records don't support a collapse of Clovis people at the time of the purported impact.

[BGHater]

-shrug-

[cripplecreek]

Dueling theories.

[dog breath]

It is so difficult to understand clearly what happened sometimes a hundred years ago let alone thousands of years ago. I don't think that the Clovis people disappeared but got absorbed into some of the newer tribes which got absorbed again by even newer tribes. It is hard to determine the difference between genetic traces of early fur traders in studies and stone age Frenchmen. As to the large fauna disappearing, well people get hungry and something extra large sized could feed a whole village for awhile. Combine that with environmental stresses and things disappear. I don't think that a single spectacular event can be blamed for the changes that occurred.

[SunkenCiv]

---

The Cycle of Cosmic Catastrophes: Flood, Fire, and Famine in the History of Civilization by Richard Firestone, Allen West, and Simon Warwick-Smith

---

• What killed the mammoths and other behemoths?
• Ancient Atomic Warfare - Religious texts and geological evidence
• Supernova debris found on Earth
• Deep freeze dealt death knell to bison (Ice Age)
• Supernova Storm Wiped Out Mammoths?
• Supernova Storm Wiped Out Mammoths?
• Scientist: Comets Blasted Early Americans
• Terrestrial Evidence of a Nuclear Catastrophe in Paleoindian Times
• Did comet start deadly cold snap?
• Diamonds tell tale of comet that killed off the cavemen
• Catastrophic Comet Chilled and Killed Ice Age Beasts (and Clovis people)
• Oregon Researchers Involved In New Clovis-Age Impact Theory (More)
• Comet May Have Doomed Mammoths
• Ice Age Ends Smashingly: Did A Comet Blow Up Over Eastern Canada? (More) (Carolina Bays)
• Climate alarmists lose another piece of evidence
• Comet Theory Collides With Clovis Research, May Explain Disappearance of Ancient People
• NSF Press Release: Comet May Have Exploded Over North America 13,000 Years Ago
• Research Team Says Extraterrestrial Impact To Blame For Ice Age Extinctions (More)
• Cosmic blast may have killed off megafauna: Scientists say early humans doomed, too
• Cosmic blast may have killed off megafauna: Scientists say early humans doomed, too
• Evidence for an extraterrestrial impact 12,900 years ago
• Site Provides Evidence For Ancient Comet Explosion (Topper - SC)
• The End of Eden: The Comet That Changed Civilization
• Great beasts peppered from space
• Did Comets Cause Ancient American Extinctions?
• Al Goodyear And The Secrets Of Ancient Americans
• The mysterious forest rings of northern Ontario
• Life Survived Catastrophic Space Rock Impact [Chesapeake Bay area]
• Research Casts New Light On History Of North America
• Exploding Asteroid Theory Strengthened By New Evidence Located In Ohio, Indiana
• First Humans To Settle Americas Came From Europe, Not From Asia....
• Diamonds Rained Down During Ice Age
• Diamonds Rained Down During Ice Age ($$$)
• First Humans To Settle Americas Came From Europe, Not From Asia Over Bering Strait -
• Tracking down abrupt climate changes (Rapid natural climate change 12,700 years ago)
• Mammoth Mystery: The Beasts' Final Years
• Scientists find signs of 13,000-year-old extinction event
• Scientists say comet killed off mammoths, saber-toothed tigers
• Diamonds Linked to Quick Cooling Eons Ago
• Six North American sites hold 12,900-year-old nanodiamond-rich soil
• Did a Comet Hit Earth 12,000 Years Ago?
• Mammoths wiped out by 'perfect storm?'
• Laser mapping may help solve the mystery of the Mima Mounds
• Humans to Blame for Extinction? - Not Necessarily So ...
• Did a Comet Cause a North American Die-Off around 13,000 Years Ago?
• Carolina bays gouged into the ground at a magnetic reversal
• North America comet theory questioned

[SunkenCiv]

Thanks BGHater.

· join · view topics · view or post blog · bookmark · post new topic · subscribe ·

[SunkenCiv]

· join list or digest · view topics · view or post blog · bookmark · post a topic · subscribe ·
	Gods Graves Glyphs	Thanks BGHater. To all -- please ping me to other topics which are appropriate for the GGG list. GGG managers are SunkenCiv, StayAt HomeMother, and Ernest_at_the_Beach
·Dogpile · Archaeologica · ArchaeoBlog · Archaeology · Biblical Archaeology Society · · Discover · Nat Geographic · Texas AM Anthro News · Yahoo Anthro & Archaeo · Google · · The Archaeology Channel · Excerpt, or Link only? · cgk's list of ping lists ·

[bigheadfred]

All your links give me a 404

[Grimmy]

404 for me too.

[Fred Nerks]

The requested document does not exist on this server.

bummer.

GREAT BEASTS PEPPERED FROM SPACE

The discovery follows on from the group's previous research which claimed a more recent space collision - some 13,000 years ago.

...The researchers reported the discovery of sediment at more than 20 sites across North America that contained exotic materials: tiny spheres of glass and carbon, ultra-small specks of diamond and amounts of the rare element iridium that were too high to be terrestrial.

The scientists also found a black layer which, they argued, was the charcoal deposited by wildfires that swept the continent after the space object smashed into the Earth's atmosphere...

[naturalman1975]

There’s an extra /focus in each of them.

[Grimmy]

“There’s an extra /focus in each of them.”

Ok, assume I’m a techtard, since it’s a mostly true condition.

The extra focus, whatsat mean? Should I stare at it extra hard to make it work?

[naturalman1975]

Click on the link.

The page will open (with the error message saying it doesn’t exist) but the address will be in the address bar of your browser.

In that address will be a part that reads /focus/focus

Click on the address to edit out one of the /focus and now the address should take you to the page.

So

http://www.freerepublic.com/focus/focus/news/2020430/posts

which doesn’t work.

Becomes

http://www.freerepublic.com/focus/news/2020430/posts

which does.

[Grimmy]

very cool. thanks.

[Fred Nerks]

Diamonds tell tale of comet that killed off the cavemen
Guardian ^ | 5-20-07 | Robin McKie

http://www.freerepublic.com/focus/news/1836898/posts

It works! Thanks.

[bigheadfred]

Work, work, work... :-)

Thanxs, Man! :-)

[SunkenCiv]

Wow, I did it again... [blush]

[SunkenCiv]

Thanks naturalman1975.

• What killed the mammoths and other behemoths?
• Ancient Atomic Warfare - Religious texts and geological evidence
• Supernova debris found on Earth
• Deep freeze dealt death knell to bison (Ice Age)
• Supernova Storm Wiped Out Mammoths?
• Supernova Storm Wiped Out Mammoths?
• Scientist: Comets Blasted Early Americans
• Terrestrial Evidence of a Nuclear Catastrophe in Paleoindian Times
• Did comet start deadly cold snap?
• Diamonds tell tale of comet that killed off the cavemen
• Catastrophic Comet Chilled and Killed Ice Age Beasts (and Clovis people)
• Oregon Researchers Involved In New Clovis-Age Impact Theory (More)
• Comet May Have Doomed Mammoths
• Ice Age Ends Smashingly: Did A Comet Blow Up Over Eastern Canada? (More) (Carolina Bays)
• Climate alarmists lose another piece of evidence
• Comet Theory Collides With Clovis Research, May Explain Disappearance of Ancient People
• NSF Press Release: Comet May Have Exploded Over North America 13,000 Years Ago
• Research Team Says Extraterrestrial Impact To Blame For Ice Age Extinctions (More)
• Cosmic blast may have killed off megafauna: Scientists say early humans doomed, too
• Cosmic blast may have killed off megafauna: Scientists say early humans doomed, too
• Evidence for an extraterrestrial impact 12,900 years ago
• Site Provides Evidence For Ancient Comet Explosion (Topper - SC)
• The End of Eden: The Comet That Changed Civilization
• Great beasts peppered from space
• Did Comets Cause Ancient American Extinctions?
• Al Goodyear And The Secrets Of Ancient Americans
• The mysterious forest rings of northern Ontario
• Life Survived Catastrophic Space Rock Impact [Chesapeake Bay area]
• Research Casts New Light On History Of North America
• Exploding Asteroid Theory Strengthened By New Evidence Located In Ohio, Indiana
• First Humans To Settle Americas Came From Europe, Not From Asia....
• Diamonds Rained Down During Ice Age
• Diamonds Rained Down During Ice Age ($$$)
• First Humans To Settle Americas Came From Europe, Not From Asia Over Bering Strait -
• Tracking down abrupt climate changes (Rapid natural climate change 12,700 years ago)
• Mammoth Mystery: The Beasts' Final Years
• Scientists find signs of 13,000-year-old extinction event
• Scientists say comet killed off mammoths, saber-toothed tigers
• Diamonds Linked to Quick Cooling Eons Ago
• Six North American sites hold 12,900-year-old nanodiamond-rich soil
• Did a Comet Hit Earth 12,000 Years Ago?
• Mammoths wiped out by 'perfect storm?'
• Laser mapping may help solve the mystery of the Mima Mounds
• Humans to Blame for Extinction? - Not Necessarily So ...
• Did a Comet Cause a North American Die-Off around 13,000 Years Ago?
• Carolina bays gouged into the ground at a magnetic reversal
• North America comet theory questioned

[SunkenCiv]

http://www.freerepublic.com/focus/chat/2361358/posts?page=18#18

[Grimmy]

Thanks but sheesh. We ain’t so lazy that we can’t delete a bit of /focus from a addy.