Exploring abrupt climate change induced by comets and asteroids during human history

YDB impact researchers cite confirmations in recent PNAS paper

The PNAS paper has a helpful bibliography of recent publications supportive of the hypothesis. It’s worth a separate block quote below.

Nice how the links take you to the cites themselves at the PNAS website.

“Some independent workers have been unable to reproduce earlier YDB results for MSp, CSp, and NDs (68), as summarized in a “News Focus” piece in Science (9), which claims that the YDB evidence is “not reproducible” by independent researchers. Refuting this view, multiple groups have confirmed the presence of abundant YDB markers, although sometimes proposing alternate hypotheses for their origin. For example, Mahaney et al. (1012) independently identified glassy spherules, CSps, high-temperature melt-rocks, shocked quartz, and a YDB black mat analogue in the Venezuelan Andes. Those authors conclude the cause was “either an asteroid or comet event that reached far into South America” at 12.9 ka. At Murray Springs, Arizona, Haynes et al. (13) observed highly elevated concentrations of YDB MSp and iridium. Abundances of MSp were 340 × higher than reported by Firestone et al. (1) and iridium was 34 × higher, an extraordinary enrichment of 3,000 × crustal abundance. Those authors stated that their findings are “consistent with their (Firestone et al.’s) data.” In YDB sediments from North America and Europe, Andronikov et al. (2011) reported anomalous enrichments in rare earth elements (REE) and “overall higher concentrations of both Os and Ir [osmium and iridium]” that could “support the hypothesis that an impact occurred shortly before the beginning of the YD cooling 12.9 ka.”. Tian et al. (14) observed abundant cubic NDs at Lommel, Belgium, and concluded that “our findings confirm … the existence of diamond nanoparticles also in this European YDB layer.” The NDs occur within the same layer in which Firestone et al. (1) found impact-related materials. Similarly, at a YDB site in the Netherlands, Van Hoesel et al.§observed “carbon aggregates [consistent with] nanodiamond.” Recently, Higgins et al. independently announced a 4- to 4.5-km-wide YDB candidate crater named Corossol in the Gulf of St. Lawrence, containing basal sedimentary fill dating to 12.9 ka. If confirmed, it will be the largest known crater in North and South America within the last 35 million years

Because of the controversial nature of the YD impact debate, we have examined a diverse assemblage of YDB markers at Lake Cuitzeo using a more comprehensive array of analytical techniques than in previous investigations. In addition, different researchers at multiple institutions confirmed the key results.”

One Response

  1. I just edited the Younger Dryas entry on Wikipedia. The end of the “History of the hypothesis” section now ends with:

    In March 2012 a study of a layer directly beneath a 10 cm thick carbon-rich layer of lake sediment from Lake Cuitzeo in the central Mexican state of Guanajuato showed that immediately below the layer were carbon spherules, magnetic spherules, and three allotropes of nanodiamonds (including lonsdaleite), all of which “are consistent with” an impact event around 12.9 kya and “cannot be explained by any terrestrial mechanism”.[13]

    I also edited the section now labeled “Controversy over the hypothesis,” from its previous label “Criticism of the hypothesis.”

    I also added to the end of that section:

    Attention should also be addressed to the section above “History of the hypothesis” in which are listed papers rebutting skeptical work. (Duplication of these other papers in this current section is deemed unnecessary.)

    I also edited the “Lonsdaleite” entry on Wikipedia to include Lake Cuitzeo.

    I don’t make a habit of editing WIkipedia. Maybe 5-10 edits a year on varying subjects. These are my first on the YDB.

    If anyone here has a problem with me doing this, let me know your concerns.

    I do NOT intend to use Wikipedia as a battleground with the Pinters, Daultons and Hollidays of this world. I assume they are also gentlemen and want a full accounting of the advancement of the “controversy.” I won’t delete anyone else’s additions, nor twist their meaning in any way. They have their right to put their two cents in.

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