Comet or gamma burst 13k years ago?

[Dr Mordrid]

A two parter; evidence of a catastrophic impact event in paloeindian N. America at nearly the same time as a possible supernova or gamma ray burst event documented in 2001 by researchers at Lawrence Berkeley.

A gamma ray burst is the focussed energy beam given off by the poles of supernovae and "feeding" black holes.

IMO this gets very weird....and just a bit too coincidental

Link....

Did a comet wipe out prehistoric Americans?

The Clovis people of North America, flourishing some 13,000 years ago, had a mastery of stone weaponry that stood them in good stead against the constant threat of large carnivores, such as American lions and giant short-faced bears. It's unlikely, however, that they thought death would come from the sky.

According to results presented by a team of 25 researchers this week at the American Geophysical Union meeting in Acapulco, Mexico, that's where the Clovis people's doom came from. Citing several lines of evidence, the team suggests that a wayward comet hurtled into Earth's atmosphere around 12,900 years ago, fractured into pieces and exploded in giant fireballs. Debris seems to have settled as far afield as Europe.
>
Exactly where the explosion might have occurred is uncertain, but several clues point to the north of the continent. Levels of the apparent extraterrestrial debris, for example, are highest at the Gainey archaeological site in Michigan, just beyond the southern reach of North America's primary ice sheet 12,900 years ago. Moreover, levels decrease the further you go from Gainey, suggesting that the comet blew up largely over Canada – perhaps over Ontario or the Hudson Bay region.

However, this cosmic wallop does not seem to have left behind any obvious crater.
In all probability, says Arizona-based geophysicist and team member Allen West, "whatever hit us was a low-density object" that fragmented as it entered the atmosphere. The disintegrating pieces could then have blown up in a series of massive aerial explosions. Alternatively, some might have crashed into the 3-kilometre-thick ice sheet. West notes that such craters "would have been ice-walled and basically melted away at the end of the last ice age", leaving few traces.

If the team's impact theory holds up under scrutiny it could help explain three mysterious events that coincided around 12,900 years ago.
>
>

Now here's what really got me going; in 2001 there was a paper documenting an event in the same area near the same time frame;

Paper by Richard B. Firestone, Lawrence Berkeley National Laboratory, and William Topping, Consultant, Baldwin, Michigan

TERRESTRIAL EVIDENCE OF A NUCLEAR CATASTROPHE IN PALEOINDIAN TIMES

THE PALEOINDIAN OCCUPATION of North America, theoretically the point of entry of the first people to the Americas, is traditionally assumed to have occurred within a short time span beginning at about 12,000 yr B.P. This is inconsistent with much older South American dates of around 32,000 yr B.P.1 and the similarity of the Paleoindian toolkit to Mousterian traditions that disappeared about 30,000 years ago.2 A pattern of unusually young radiocarbon dates in the Northeast has been noted by Bonnichsen and Will.3,4 Our research indicates that the entire Great Lakes region (and beyond) was subjected to particle bombardment and a catastrophic nuclear irradiation that produced secondary thermal neutrons from cosmic ray interactions. The neutrons produced unusually large quantities of 239 Pu and substantially altered the natural uranium abundance ratios ( 235 U/238 U) in artifacts and in other exposed materials including cherts, sediments, and the entire landscape. These neutrons necessarily transmuted residual nitrogen ( 14 N) in the dated charcoals to radiocarbon, thus explaining anomalous dates.
>
The Paleoindian catastrophe was large by standards of all suspected cosmic occurrences. Normal geomagnetic conditions would focus cosmic rays towards the magnetic poles, concentrating their severity in those regions. However, low magnetic field intensity during a geomagnetic excursion may have allowed excessive cosmic rays to strike northeastern North America. (Whether the geomagnetic excursion admitted cosmic radiation, or the radiation caused the excursion, is uncertain. Given our present state of knowledge, cause and effect in this instance are unclear.) The presence of a nearby small and dense interstellar cloud may explain the origin of the particle bombardment.50 The size of the initial catastrophe may be too large for a solar flare, but a sufficiently powerful nearby supernova or cosmic ray jet could account for it. It appears that the catastrophe initiated a sequence of events that may have included solar flares, impacts, and secondary cosmic ray bombardments.

A devastating effect on Earth

The enormous energy released by the catastrophe at 12,500 yr B.P. could have heated the atmosphere to over 1000°C over Michigan, and the neutron flux at more northern locations would have melted considerable glacial ice. Radiation effects on plants and animals exposed to the cosmic rays would have been lethal, comparable to being irradiated in a 5-megawatt reactor more than 100 seconds.

The overall pattern of the catastrophe matches the pattern of mass extinction before Holocene times. The Western Hemisphere was more affected than the Eastern, North America more than South America, and eastern North America more than western North America.51,52,53 Extinction in the Great Lakes area was more rapid and pronounced than elsewhere. Larger animals were more affected than smaller ones, a pattern that conforms to the expectation that radiation exposure affects large bodies more than smaller ones.54,55 Sharp fluctuations of 14 C in the Icelandic marine sediments at each geomagnetic excursion are interesting; because global carbon deposits in the ocean sediments at a rate of only about 0.0005 percent a year, a sudden increase in sediment 14 C may reflect the rapid die-off of organisms that incorporated radiocarbon shortly after bombardment.

Massive radiation would be expected to cause major mutations in plant life. Maize probably evolved by macro-mutation at that time,55,56 and plant domestication of possibly mutated forms appears worldwide after the Late Glacial period. For example, there was a rapid transition from wild to domesticated grains in the Near East after the catastrophe.
>

[Dr Mordrid]

More on this event indicating the "comet" may have been a supernova remnant;

Article....

Supernova Explosion May Have Caused Mammoth Extinction

Contact: Dan Krotz, 510-486-4019, dakrotz@lbl.gov

BERKELEY, CA – A distant supernova that exploded 41,000 years ago may have led to the extinction of the mammoth, according to research conducted by nuclear scientist Richard Firestone of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab).

Firestone, who collaborated with Arizona geologist Allen West on this study, unveiled this theory Sept. 24 at the 2nd International Conference "The World of Elephants" in Hot Springs, SD. Their theory joins the list of possible culprits responsible for the demise of mammoths, which last roamed North America roughly 13,000 years ago. Scientists have long eyed climate change, disease, or intensive hunting by humans as likely suspects.

Now, a supernova may join the lineup. Firestone and West believe that debris from a supernova explosion coalesced into low-density, comet-like objects that wreaked havoc on the solar system long ago. One such comet may have hit North America 13,000 years ago, unleashing a cataclysmic event that killed off the vast majority of mammoths and many other large North American mammals. They found evidence of this impact layer at several archaeological sites throughout North America where Clovis hunting artifacts and human-butchered mammoths have been unearthed. It has long been established that human activity ceased at these sites about 13,000 years ago, which is roughly the same time that mammoths disappeared.

They also found evidence of the supernova explosion’s initial shockwave: 34,000-year-old mammoth tusks that are peppered with tiny impact craters apparently produced by iron-rich grains traveling at an estimated 10,000 kilometers per second. These grains may have been emitted from a supernova that exploded roughly 7,000 years earlier and about 250 light years from Earth.

“Our research indicates that a 10-kilometer-wide comet, which may have been composed from the remnants of a supernova explosion, could have hit North America 13,000 years ago,” says Firestone. “This event was preceded by an intense blast of iron-rich grains that impacted the planet roughly 34,000 years ago.”

In support of the comet impact, Firestone and West found magnetic metal spherules in the sediment of nine 13,000-year-old Clovis sites in Michigan, Canada, Arizona, New Mexico and the Carolinas. Low-density carbon spherules, charcoal, and excess radioactivity were also found at these sites.

“Armed with only a magnet and a Geiger counter, we found the magnetic particles in the well-dated Clovis layer all over North America where no one had looked before,” says Firestone.

Analysis of the magnetic particles by Prompt Gamma Activation Analysis at the Budapest Reactor and by Neutron Activation Analysis at Canada’s Becquerel Laboratories revealed that they are rich in titanium, iron, manganese, vanadium, rare earth elements, thorium, and uranium. This composition is very similar to lunar igneous rocks, called KREEP, which were discovered on the moon by the Apollo astronauts, and have also been found in lunar meteorites that fell to Earth in the Middle East an estimated 10,000 years ago.

“This suggests that the Earth, moon, and the entire solar system were bombarded by similar materials, which we believe were the remnants of the supernova explosion 41,000 years ago,” says Firestone.

In addition, Berkeley Lab’s Al Smith used the Lab’s Low-Background Counting Facility to detect the radioactive isotope potassium-40 in several Clovis arrowhead fragments. Researchers at Becquerel Laboratories also found that some Clovis layer sediment samples are significantly enriched with this isotope.
>

[Technoid]

Heh, and up to now the official PC reason for the Mammoth Extinction has been the "Evil humans"

Anything bad that happens, blame it one the "Evil humans"