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I few trivial searches disqualify your "watershed event": The "particles" you mention are most probably Highly siderophile elements (HSE) - which indeed only fo

I few trivial searches disqualify your "watershed event": The "particles" you mention are most probably Highly siderophile elements (HSE) - which indeed only form upwards of 2000°C. That doesn't mean they have to come from outer space, though, as they are also present in earth's upper mantle[0]. Surface HSE presence can therefore also be explained by volcanic activity. And indeed, a July 2020 publication has shown that the present evidence and thus the Younger Drias Event can also be explained by a series of volcanic eruptions[1]. [0] = https://doi.org/10.1016/j.chemer.2008.10.001 https://doi.org/10.1016/j.chemer.2008.10.001 [1] = https://advances.sciencemag.org/content/6/31/eaax8587 https://advances.sciencemag.org/content/6/31/eaax8587

jcranmer 6y ago
> The "particles" you mention are most probably Highly siderophile elements (HSE) From what I saw of some of the articles I was reading, it was nanodiamonds and magnetic microspherules. I'm getting this mostly from [1], which is definitely a strong critical take on the evidence, suggesting that the methodology for identifying these particles is sufficiently subjective that researchers knowing where the samples are to have occurred is biasing their interpretation of the results to find a sharp distinction around the Younger Dryas threshold that isn't corroborated if that context is removed. [1] https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0155470 https://journals.plos.org/plosone/article?id=10.1371/journal...
- ncmncm 6y ago
  You can quibble over this or that equivocal result, but the very sharp platinum concentration results at numerous sites are not so easily dismissed, and are (therefore?) notably not mentioned.
  - jcranmer 6y ago
    When I first poked at this hypothesis, I came away feeling that the best characterization was that it's an area of academic dispute where both sides have credibility and neither side can be accurately considered fringe or mainstream, in contrast to your initial comment. Nothing you have said has shaken that belief, and I have no relevant scientific expertise to offer in support of one side or the other. I have my personal opinion on which side I feel has the better evidence and prefer on the balance of probabilities, but what that opinion is is ultimately unimportant. That said, there is one thing that mildly concerned me when I read your first comment and that your later comments have only reinforced my impressions. You seem to be approaching this topic from an evangelical perspective, and not a scientific one: that there is a core belief, this needs to be disseminated to as many people as possible, and that anything that challenges that belief needs to be swiftly eliminated. Your rhetoric--"Neanderthal", "black eye for geology"--does not help your argument. I only bring this up because I saw a video over the weekend [1] discussing Flat Earthers and some of the argumentation style they used, and on reflection, it was striking how similar your comments were, just on an acceptable opinion rather than a loony idea. [1] https://www.youtube.com/watch?v=JTfhYyTuT44 https://www.youtube.com/watch?v=JTfhYyTuT44
    - ncmncm 6y ago
      Your comment amounts to namecalling, and offers nothing of substance to respond to.
ncmncm 6y ago
Trivial searches yield trivial results. That [1] really only examines ratios of osmium to platinum-group elements is telling. At only one place in the paper do they admit that the osmium/osmium isotope ratios found in their samples, from the one cave, do, in fact, match a known bolide. They very carefully avoid addressing the extreme Pt abundances found in the YDB layer at dozens of sites. This is akin to others complaining that iridium abundance at the strata is not especially elevated, without addressing platinum, which lacks other explanation. "Lack of clear consensus" cited in the paper is revealed to mean that certain individuals, like them, have disagreed, without addressing faulty details. Such individuals have made claims that spherules identified as carbon are spores, without having examined any of them, or that they are not present at all, but which turn out to refer to layers that do not coincide with the YDB. The European volcanic eruption mentioned is known to have occurred some centuries before the YDB. You can't refute results from dozens of sites with equivocal results from a single site.

jcranmer 6y ago

> The "particles" you mention are most probably Highly siderophile elements (HSE) From what I saw of some of the articles I was reading, it was nanodiamonds and magnetic microspherules. I'm getting this mostly from [1], which is definitely a strong critical take on the evidence, suggesting that the methodology for identifying these particles is sufficiently subjective that researchers knowing where the samples are to have occurred is biasing their interpretation of the results to find a sharp distinction around the Younger Dryas threshold that isn't corroborated if that context is removed. [1] https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0155470 https://journals.plos.org/plosone/article?id=10.1371/journal...

ncmncm 6y ago
You can quibble over this or that equivocal result, but the very sharp platinum concentration results at numerous sites are not so easily dismissed, and are (therefore?) notably not mentioned.
- jcranmer 6y ago
  When I first poked at this hypothesis, I came away feeling that the best characterization was that it's an area of academic dispute where both sides have credibility and neither side can be accurately considered fringe or mainstream, in contrast to your initial comment. Nothing you have said has shaken that belief, and I have no relevant scientific expertise to offer in support of one side or the other. I have my personal opinion on which side I feel has the better evidence and prefer on the balance of probabilities, but what that opinion is is ultimately unimportant. That said, there is one thing that mildly concerned me when I read your first comment and that your later comments have only reinforced my impressions. You seem to be approaching this topic from an evangelical perspective, and not a scientific one: that there is a core belief, this needs to be disseminated to as many people as possible, and that anything that challenges that belief needs to be swiftly eliminated. Your rhetoric--"Neanderthal", "black eye for geology"--does not help your argument. I only bring this up because I saw a video over the weekend [1] discussing Flat Earthers and some of the argumentation style they used, and on reflection, it was striking how similar your comments were, just on an acceptable opinion rather than a loony idea. [1] https://www.youtube.com/watch?v=JTfhYyTuT44 https://www.youtube.com/watch?v=JTfhYyTuT44
  - ncmncm 6y ago
    Your comment amounts to namecalling, and offers nothing of substance to respond to.

ncmncm 6y ago

Trivial searches yield trivial results. That [1] really only examines ratios of osmium to platinum-group elements is telling. At only one place in the paper do they admit that the osmium/osmium isotope ratios found in their samples, from the one cave, do, in fact, match a known bolide. They very carefully avoid addressing the extreme Pt abundances found in the YDB layer at dozens of sites. This is akin to others complaining that iridium abundance at the strata is not especially elevated, without addressing platinum, which lacks other explanation. "Lack of clear consensus" cited in the paper is revealed to mean that certain individuals, like them, have disagreed, without addressing faulty details. Such individuals have made claims that spherules identified as carbon are spores, without having examined any of them, or that they are not present at all, but which turn out to refer to layers that do not coincide with the YDB. The European volcanic eruption mentioned is known to have occurred some centuries before the YDB. You can't refute results from dozens of sites with equivocal results from a single site.