Clovis Comet paper #1 read article in Geology

Papers finding "consistent with" data and chemistry are necessary, in the long slog until a real impact event is found and vetted. Some (Daulton, etc.) will never be convinced, but objective results like this are stones in the foundation. Thanks for finding this, George.

The full Melott et al 2009 paper is at http://geology.gsapubs.org/content/38/4/355.full.pdf It probably was linked long ago, but... Carlson refers to a 2010 Melott paper.

Carlson: "Ultimately, the bolide-forcing hypothesis predicts that the Younger Dryas is a unique deglacial event, as suggested by Broecker (2006)." Ed here, for one, will argue the YD isn't unique, though its "deglacial event" qualities and forcings may be unique (though the YD was, as we and they all know, not a deglaciation event at all). The point being that with other impacts, other ammonia spikes should be in the ice record - if the relatively small Tunguska event is - and to the non-catastrophists these would be used to confuse the ammonia-YD argument. On the contrary, this ammonia record may now possibly be used to identify those other (likely Encke progenitor fragment) bolides/impactors in their Holocene periods.

correction: ..."in their proper Holocene periods."

Carlson picked up on this use in his last paragraph, as I read him. But I should also extend that "Holocene" period to include the Pleistocene. It would, of course, be interesting to see how well those ammonia spikes (when all are identified) line up with Bond Events and D-O Events. One would expect reasonable alignment - enough to predict a correlation, even.

Okay, the Merlott et al abstract was submitted in 2009 and accepted in 2009, but the paper was published in 2010.

Hello for All George, does the amount of ammonia coming from comet fragments explosions would be sufficient to contaminate the water accumulated in the new lagoons (craters), and poison the surviving animals? It is common to find megafauna fossils in these palaeolagoons. https://sites.google.com/site/cosmopier/impact-craters/end-pleistocene-palaeolagoons regards pierson

A pre-print of the Mellot paper was submitted to the Physics ArXiV server and is free to download on this link http://arxiv.org/ftp/arxiv/papers/0907/0907.1067.pdf. The one Steve links to is only available to subscribers.

Chicken, the article you refer to can be downloaded free from this site: http://geology.gsapubs.org/reports/most-read The articles are all OPEN ACCESS. I just downloaded three, including the Carlson (2010) paper on the YDR.

Also downloaded from the GSA site: Matthew J. Fouch, "The Yellowstone Hotspot: Plume or Not?" (May 2012) At issue is the Morgan Mantle Plume theory for Yellowstone: Morgan, W.J., 1971, "Convection plumes in the lower mantle": Nature, v. 230, p. 42–43. The paper argues against this, similar to the website mantleplumes.org Actually, the hotspot probably resulted from a comet impact in the Modoc Plateau, NE California during the Miocene, 17 Ma BP. There, as caldera was discovered in a Colorado School of Mines MS thesis. Years ago, I happened to come across a GSA abstract by the author and his adviser. The impact is easily recgnized by its rebound, the typical central uplift in the innermost ring in diatomaceous earth, then at the cratonal margin, known locally as Chalk Mountain, map coordinates 40.994,-121.809. For the Yellowstone hotspot track leading from the Modoc Plateau, CA, to the present day National Park, WY, see this map: http://www.mantleplumes.org/images/YellowstoneGeol600.gif

Thanks, Jenkoul, for a provocative link and duscission.I'm certainly not expert enough to weigh in here on the science itself, but I would think National Geographic would have caught the problem noted by Jack Adler before publishing if Adler's claim were credible.Adler seems to have a dog in this fight, but he also produces what looks like credible evidence. Still, it doesn't seem that he publishes in refereed journals or top magazines. Why not?On those grounds, I'm inclined to favor the National Geographic article. Apparently, the sponsors of the researchers also seem to have that inclination since they are talking about sending a team back for a bottom search. That should settle the issue once and for all.I love this kind of duscission, because it illuminates how science unfolds in the real world.Readers, do you have anything to add?Fred Bortz Science and technology books for young readers (www.fredbortz.com) and Science book reviews (www.scienceshelf.com)

I like a good glass of merlot as much as the next guy. And I'm sure Adrian Melott is a fine scientist. But I wouldn’t go so far as to confuse him with a fine wine. (Pun intended)

Came upon the following: a disintegration of an asteroid caught by the Hubble telescope. It's believed two asteroids collided and the debris trail was then created by light pressure on the various fragments and sweeps off to one side of its orbit. It is far more likely that a comet broke apart from an asteroid collision than with another type of object because there are so many asteroids. It's possible the comet was struck by only a small piece of space debris; not enough to explode it, just enough to shatter it so it broke into many pieces. If a debris trail like this was created it would have provided a far larger target for the earth to plow through than debris trailing a comet in close to the same orbit. The two orbits wouldn't have had to intersect exactly. http://www.jpl.nasa.gov/images/asteroid/20100203/asteroid20100203-full.jpg