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I read about deriving the oxygen content in the atmosphere in the Cretaceous by analyzing the air trapped in bubbles in amber from that period, but I have also found papers disputing the study's methods and showing that air isn't actually trapped in the bubbles because it's capable of diffusing through the amber (the amber isn't a perfect sealant), and thus the air found in that amber isn't necessarily as ancient as the amber itself.

My problem is is that almost all the relevant papers are from the late 80's; all those I've found are pro- or con-, I don't have the background to tell who is right, I haven't found a source that describes an actual consensus the field would have come to since then, and I see the claim about the original study showing what oxygen levels were in the Cretaceous cited in various places, but I find it hard to tell if it's because the objections were dismissed or if it's because it's a zombie claim.

Some sources:

Does anyone know if a consensus was arrived at on this question, and/or if one side is clearly more right than the other?

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  • $\begingroup$ There's another paper here - droyer.web.wesleyan.edu/Royer_2014_Treatise.pdf - the telling thing is that it dosen't mention amber at all in a recent review of the topic. $\endgroup$ – Andrew Jon Dodds May 11 '17 at 12:22
  • $\begingroup$ Berner and Landis wrote another interesting paper that refers to their work from 1988 in May 2018 that can be found here ajsonline.org/content/318/5/590.abstract DOI:10.2475/05.2018.06 $\endgroup$ – Jojostack Jan 30 at 9:18
  • $\begingroup$ @jojostack Thank you very much ! On the one hand it's frustrating that again it's the same original authors addressing the question, but on the other hand the fact that they're still working to support their hypothesis in 2018, and (according to the abstract) came to a more tentative conclusion this time, suggests that the claim is at least not consensual in the field. $\endgroup$ – Oosaka Feb 4 at 18:42
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There is at least a fair degree of consensus (there will always be naysayers) that the results that were performed back in the 80s and 90s by Berner and Landis were false positives that could not be confirmed by further investigations. A good historical account of this can be found for instance in Nick Lane's book "Oxygen" (first published in 2002). Quoting from this book:

The overall consensus, which has now persisted for more than a decade, was that the air trapped in amber could not have been ancient [...]

That "could not have been" has an air of finality about it, and you can probably take this book's word as accurate. However, all of the amber in the world has not been examined, so I would say chances may be slim but not none that some will be found containing traces of an ancient atmosphere. Probably part on the answer depends on how old the amber is, and how it was preserved. A very different question is whether gases in the amber can be regarded as representative of the atmosphere of origin, or useful. Perhaps reactions with the amber (oxidation) during burial have altered it beyond recognition.

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