Younger Dryas impact model confuses comet facts, defies airburst physics
Authors:
Boslough et al
Excerpt:
In PNAS, Wittke et al. (1) present evidence that they indicate supports major airbursts and/or impacts at the beginning of the Younger Dryas, as proposed by Firestone et al. (2). One of the major criticisms of the hypothesis has been the lack of any physics-based model for the hypothesized event (3). Wittke et al. (1) attempt to remedy this flaw by including a section entitled “Preliminary Impact Model.” Their model diverges significantly from the original but still provides no physics based argument and demonstrates a misunderstanding of comets, as well as the physics of airbursts.
Counterargument:
Reply to Boslough et al.: Decades of comet research counter their claims
Authors:
Napier et al
Excerpt:
Boslough et al. (1) offer no alternate explanation for ∼10 million tonnes of Younger Dryas spherules recovered from 18 sites across ∼50 million square kilometers of North America, Europe, and the Middle East (2). In addition, the authors claim that our hypothesis “demonstrates a misunderstanding of comets.” However, the misunderstanding is theirs alone, because the model they criticize is their own creation and not the one we adopt, which derives from a substantial body of comet literature (e.g., ref. 3).
And its getting personal...
3 comments:
What about Andrew Madden in Oklahoma, apparently he presented an abstract yesterday at the GSA meeting in Denver on independently quantified nanodiamonds across the Younger Dryas horizon and all the way to the present with confirmation.
Does anybody here communicate?
I follow the papers and press releases. I dont have a lot of time to communicate directly. I have a handful of researchers I talk to, but not many.
As soon s it gets published, I'll post it here. I'm completely open to an impact (or open the other way), but I have doubts about it being a killer.
Apparently Corossol is too old, but I have discovered a very large pseudo crater just south of lake Nipigon that appears to be in the exact right place to initiate an Agassiz Moorhead phase discharge event. So it is not as if possibilities of an unusual event are not plausible here. The trick is to falsify the hypothesized scenario. If the quantified nanodiamonds cannot be explained or falsified away, then most of these people have some distinct problems to explain, and this kind of acrimony is not particularly helpful. My scenario is fairly simple, explosive volatile impact onto the ice, subglacial drawdown of Agassiz through the lakes, and then erosive scouring of the resulting circular feature transposed onto the Canadian shield. Sparse silicate and metallic spherules due to embedded boulders, gravel, sand and rock flour and abundant nanodiamonds due to a carbonaceous impact. Now I don't believe that for a minute, but it explains a lot more than just the impact, as there are equally controversial problems with Agassiz at the Moorhead. I haved proposed taking another look at the remarkably sharp and thick grey mud sediments interrupting the red varves, that extend throughout Lake Superior all the way down into lower Lake Michigan, the Wilmette bed cores, which haven't been properly dated beyond the original work by Steve Colman. For volatile carbon ice impacts an ozone collapse in inevitable and that helps explain some of the megafaunal extinctions. Thanks.
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