Extraterrestrial impact caused Younger Dryas?

[JusDennis]

Ok, I read the mans paper. I don't agree.

Time will tell

 

[Evo]

Here is another paper that disputes the extraterrestrial impact theory.

Abstract - Paleoindian demography and the extraterrestrial
impact hypothesis

Briggs Buchanan*, Mark Collard, and Kevan Edinborough

Recently it has been suggested that one or more large extraterrestrial
(ET) objects struck northern North America 12,900 100
calendar years before present (calBP) [Firestone RB, et al. (2007)
Proc Natl Acad Sci USA 104: 16016–16021]. This impact is claimed to
have triggered the Younger Dryas major cooling event and resulted
in the extinction of the North American megafauna. The
impact is also claimed to have caused major cultural changes and
population decline among the Paleoindians. Here, we report a
study in which 1,500 radiocarbon dates from archaeological sites
in Canada and the United States were used to test the hypothesis
that the ET resulted in population decline among the Paleoindians.
Following recent studies [e.g., Gamble C, Davies W, Pettitt P,
Hazelwood L, Richards M (2005) Camb Archaeol J 15:193–223), the
summed probability distribution of the calibrated dates was used
to identify probable changes in human population size between
15,000 and 9,000 calBP. Subsequently, potential biases were evaluated
by modeling and spatial analysis of the dated occupations.
The results of the analyses were not consistent with the predictions
of extraterrestrial impact hypothesis. No evidence of a population
decline among the Paleoindians at 12,900 100 calBP was found.
Thus, minimally, the study suggests the extraterrestrial impact
hypothesis should be amended.

http://www.hecc.ubc.ca/pdf/PaleoDem_PNAS2008.pdf

 

[JusDennis]

Ok

Buchanon et al. disagrees with Firestone et al.

I am not qualified to be the arbiter in that debate. I'm an old ex GI who still knows his place in the firing line. I ‘m not sure how it fits into all of the different scientists pet theories, or research. I think, after all of the fur stops flying, it will turn out that they are all absolutely correct. But each holding a different part of the elephant.

 

[matthyaouw]

Thank you for your opinion. In fact I see no evidence of any uplift whatsoever.

I have to wonder where (if anywhere) you have looked and if you indeed know what evidence for uplift would look like. On page 2 of http://www.gly.fsu.edu/~holm/Tull and Holm.pdf you will see that there are a series of thrust faults around the area you describe. Take note.

I do, however, see compelling visual evidence of massive surface compression shock waves.

I am still waiting for you to present it, but I have a feeling my wait will be indefinate.

To say that it did so without trace is much more of a stretch than pointing to the obvious epicenter of a giant blast zone and saying it happened right there.

I am not saying there was not an impact. I am not saying there is not an impact site somewhere in the US. I am saying there is no evidence for one wher you claim.

I have stated my qualitifacations for recognizing a blast zone. I haven't heard anything from you on that account. What do you know of the ground effects of powerful explosions? Did you learn it in a classroom? Or on a battlefield?

Classroom, of course. And in the course of my learning I would bet that I learned a hell of a lot more than you about how rock responds to heat, pressure and ET impacts on such large scales.

You, my good man are starting to sound a bit strident. Like the Wizard of Oz. Frantically trying to cover while shouting into the microphone "Pay no attention to the old man behind the curtain." And since you clearly have no idea what a blast zone looks like your opinion in this matter is wholely useless.

And you are starting to sound like every other nutjob that ever brought their own pet theory along to an internet forum. By your own admission you have no evidence beyond what you have gathered from a cursory glance at google earth, yet you are convinced to the point of certainty that you are right and seem to be ready to defend your position to the death. You clearly have no evidence to support your position or refute anyone elses therefore your opinion in the matter is useless.


Seriously, if what you say is true, you will find evidence for it if you look in the right places. Never mind trying to tell everyone else they are wrong. Their being wrong would not automatically make you right. What you need to fucus on is supporting your positon. Go away and find out how rock would respond to the heat and pressure you describe, or what telltale signatures an ET impactor may leave. Then go and look for these things. Come back if you find them. You have already stated your case, and until you have something to add in support of this, the discussion will not progress any further.

 

[Mk]

Evo, I do not quite understand your logic or what you mean by, "the Firestone paper has been thoroughly debunked." How? Do you mean the hypothesis of an extraterrestrial impact impacting the Clovis culture itself, or also the supporting original research published in the paper?

 

[Evo]

Evo, I do not quite understand your logic or what you mean by, "the Firestone paper has been thoroughly debunked." How? Do you mean the hypothesis of an extraterrestrial impact impacting the Clovis culture itself, or also the supporting original research published in the paper?

There are several papers. One was sent to me by the author himself, I will need to check if I can post it. He is an authority on Clovis and has shown why what they propose did not happen, the archeological evidence isn't there.

Here is a good paper.

http://www.gsajournals.org/perlserv/?request=get-document&doi=10.1130%2FGSAT01801GW.1

 

[Andre]

As far as I can see it, there may or may not have been an extraterrestrial event but it can be considered refuted that this hypothetical event had any significant impact on climatological changes and extinctions of species.

 

[Mammo]

As far as I can see it, there may or may not have been an extraterrestrial event but it can be considered refuted that this hypothetical event had any significant impact on climatological changes and extinctions of species.

How do you come to that conclusion? A micrometeorite bombardment which persisted long enough to leave a blanket deposited layer, which is still magnetic enough to deflect a compass (I saw it on TV), must have been a spectacular event. It seems reasonable to assume that it is possible that the event did cause climate change. Here is a paper which discusses this type of subject: Violette 2005 report.

 

[Andre]

How do you come to that conclusion?

Please reread the thread then. Essentially all isotope indications of the start of the Younger Dryas (YD) match the isotope indications of the 20+ Dansgaard-Oeschger (D-O) events in the last ~70 Ka. So the YD can be seen as just another end of a D-O event, which was bound to happen regardless of any extra terrestrial event.

Second, there is no indication of the predicted wild fire spike at 12,900 y BP. (Marlon et al 2009 Wildfire responses to abrupt climate change in North America, PNAS doi10.1073pnas.0808212106 early edition)