Talk:Radiocarbon dating

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Suess's curve[edit]

Taylor, in Radiocarbon Dating page 133, refers to the calibration curves of Seuss from 1967 and 1970. Akin, in Science-based Dating in Archaeology, p. 67, says that the first results were in the 1970 paper. Does anyone have access to the 1967 paper to see if there is a calibration curve in it or just the raw data? The 1967 paper is "Bristlecone pine calibration of the radiocarbon time scale rom 4100 BC to 1500 BC", in Radiocarbon Dating and Methods of Low-Level Counting, Vienna, International Atomic Energy Agency, pp. 143–150. The 1970 paper, for comparison, is "Bristlecone-pine calibration of radiocarbon time 55200 BC to present", in Radiocarbon Variations and absolute chronology, edited by I.U. Olsson, Stockholm, Almqvist & Wiksell, pp. 303–312. Thanks for any info on these. Mike Christie (talk - contribs - library) 18:31, 1 January 2014 (UTC)

The 1967 paper seems to be very rare, see here. The 1970 paper is easy to get, but do you have it already? Zerotalk 05:37, 4 January 2014 (UTC)
I don't have it and would be interested in seeing it, if it's easy to get. For one thing, it might provide an internal reference to the 1967 paper that would make it clear whether the graph appeared there first. Mike Christie (talk - contribs - library) 13:24, 4 January 2014 (UTC)
I'll get it soon. Meanwhile, if you ask for the 1967 paper at WP:REX you might get lucky. Btw, you have mail. Zerotalk 19:43, 4 January 2014 (UTC)
I posted the request at WP:REX. Got the email and have replied; thanks! Mike Christie (talk - contribs - library) 20:06, 4 January 2014 (UTC)
The 1970 paper and its calibration curves are in your mailbox. There is mention of a preliminary curve in the 1967 paper. Zerotalk 13:11, 6 January 2014 (UTC)
Received; thanks! The mention of the curves in the 1967 paper is enough for me to get the story right in the article, I think. Mike Christie (talk - contribs - library) 13:40, 6 January 2014 (UTC)

Next steps for the article[edit]

FYI for other editors, here's what I think are the next steps on the article.

  • Finish revising the calibration section -- needs some more details on the process of developing calibration curves, and on how they are used -- simple intercepts, probabilistic methods, and Bayesian analysis for multiple data points.
  • Add a section on archaeological practice -- the secondary sources spend a good deal of time discussing how radiocarbon dating is useless without good field practice to ensure association of the sample with the context to be dated.
  • Add a section giving some examples of how radiocarbon dates have had a dramatic impact on the field, leading to a significant revision in understanding. The Chauvet Cave is one I would like to cover and maybe a couple of others. I would eliminate the list of examples; it's better to have a short list and discuss their impact.
  • Once that's done, do a pass through for consistency and make sure the article is balanced.
  • Review for what can be cut and moved to subarticles -- the article is really too long as it now stands. Create the subarticles and shrink the main article by summarizing them.
  • Copyedit pass.
  • Submit for peer review with a view to GA and FA.

-- Mike Christie (talk - contribs - library) 04:38, 4 January 2014 (UTC)

More notes:
  • This looks like a good source for one of the subarticles; just removed it from the reflist here as it's unused.
  • Would like to expand the short para on Bayesian analysis but haven't yet found a good source.
  • Have moved the calculation details to a subarticle; the section on samples should probably go too.
  • Have removed unused sources; need to go through footnotes next and ensure everything is listed in the refs.
  • Need to go through Currie's article and see what else can be used before taking this to PR.
-- Mike Christie (talk - contribs - library) 11:03, 1 July 2014 (UTC)
  • My thoughts: the article could really use a summary/overview after the lead of what carbon dates in their different forms mean, and the pitfalls of assuming they are all the same. For reasons I entirely understand, at the moment the lead is followed by an exposition from scratch of the physics which will throw most readers. The section headings lower down could also be made more explicit. Johnbod (talk) 14:11, 19 July 2014 (UTC)
    @Johnbod: I think I see your point, but I'm not entirely sure what the contents of an overview section would be. Wouldn't this duplicate the lead to some extent? Or are you saying that the overview section should focus on the method's use in archaeology? If you could give me a couple of bullet points to show what this section would say, that would be helpful. For the section headings, are you suggesting changes such as "Samples" -> "Sample materials and preparation", or "Calibration" to "Converting radiocarbon dates to calendar dates"? Mike Christie (talk - contribs - library) 10:23, 20 July 2014 (UTC)
    No, it would summarize what is below, especially in "Reporting dates", and perhaps add to it. It would explain what the notations around dates encountered in texts actually mean, and the different conventions. The section below should probably explain older conventions, some of which I think are not yet extinct. Also the need for calibration, which I don't think is really clearly explained in that section (that is covered in the lead). Or perhaps just move that section up to below the lead, even though that is well out of logical sequence. A lot more people need to know what datings they encounter actually mean than how to do the lab or calculation work. Overall the article is not very accessible; a lot of the material is very technical and fiddly, but simpler section introductions would help. Johnbod (talk) 13:00, 20 July 2014 (UTC)
    Sorry I'm being slow, but I still don't really understand what you're saying. I took a look at a couple of recent papers; the reporting conventions are quite complicated (see [1] for one I looked at) and I don't think would make much sense without some context given first -- e.g. mentions of CALIB and OxCal, and "calibrated dates". I take your point that a reader is likely to be thrown by the way the article jumps right into the physics, and I'm open to the idea of an explanatory section to start the article, but I'm not sure what it would contain. You suggest that an overview would be a version of the "Reporting dates" section, with some added material, but I think if we talk about what is reported without giving enough context to explain what it means it won't be informative.
    I confess I'm probably too deep in this article to find it easy to think about how a new reader would approach it (though CorinneSD is currently doing a very helpful peer review from a lay point of view). CorinneSD, could you comment here? Given that you didn't have any background knowledge on this topic, do you think an overview section of the sort Johnbod describes would help, and if so, what would go into such a section? Mike Christie (talk - contribs - library) 11:27, 22 July 2014 (UTC)
  • A few more thoughts from an archaeologist by request, @Mike Christie: This article is terrific, I think, and although I am not a radiocarbon expert seems very thorough. I agree with the suggestion to expand the Bayesian stats section -would these refs help? Bronk-Ramsey article or this chapter. I would also include a link at the end of the article to the optically stimulated luminescence page, see this recent review. Finally, and this is a very minor point, the paragraph on the "second radiocarbon revolution" reads a bit dated, perhaps changing "invasion of tribes" to "invasion of peoples" might be better? Hope this helps, even a bit. Ninafundisha (talk) 20:07, 7 August 2014 (UTC)
    @Ninafundisha: thanks -- this is very helpful, particularly the linked articles. I'll fix the "tribes" point, and work on the other areas. I appreciate you taking the time to look through the article. Mike Christie (talk - contribs - library) 21:57, 7 August 2014 (UTC)

Parenthesis?[edit]

In several places a left parenthesis appears to have been used in place of the "C" for "carbon". Shouldn't these be changed to "C"? If not, why not? Also, the illustration caption refers to an equation and an inequality, neither of which appear in the illustration.— Preceding unsigned comment added by 74.95.43.249 (talkcontribs)

Can you say where the parentheses appear, and which illustration you're referring to? Mike Christie (talk - contribs - library) 20:58, 8 May 2014 (UTC)
Probably anon is referring to syntax like (14C), but that is correct; the "14" is attached to the "C" not to the "(". Also the first figure does have an equation and an inequality in it. Zerotalk 00:38, 9 May 2014 (UTC)

Recent undo[edit]

I just undid this edit by Buried forest; I think the editor misunderstood that section of CALIB -- they're saying that if the correct half-life value (5,730) is used, it won't give radiocarbon years in a form CALIB can use, because CALIB expects the Libby half-life to be used. Mike Christie (talk - contribs - library) 00:22, 11 July 2014 (UTC)

Revised list of next steps[edit]

Based on various input and some comments above.

  • Expand the sentence on Bayesian analysis based on the Bronk-Ramsey article listed above. Not much more needs to go in this article; most of the extra detail could go into calibration of radiocarbon dates.
  • There is a new edition of Taylor's Radiocarbon Dating: An Archaeological Perspective coming out in September; I've ordered a copy. When it arrives I need to go through that for updates. With luck it can be used to cite the specific points below.
  • For AMS vs. beta counting, AMS standard deviations are now smaller than for beta counting; need source for this. Also cost is now apparently competitive with beta counting.
  • Would like to know what labs are left that do beta counting -- are most/all now AMS?
  • Fractionation is done by ordinary mass spectroscopy; this can either be mentioned in the section on fractionation or in the subarticle on radiocarbon dating considerations.
  • Consider reversing the axes on the INTCAL graph
  • Make sure "σ" is properly glossed when introduced.
  • Possibly use this link as a cite for the mention of the Withy Bed Copse trackway.

-- Mike Christie (talk - contribs - library) 01:44, 19 August 2014 (UTC)

Neanderthal dates[edit]

I have added a couple of sentences to the Wikipedia article based on the recent article in Nature by Higham et al. on dating Neanderthal artefacts. Higham et al. claim that many of the C14 dates obtained for Neanderthal sites are too young as a result of contamination by "young carbon". I think it is useful to mention this article as it demonstrates that the technique is still evolving and that sample preparation is extremely important, particularly for very old samples where the fraction of remaining C14 is very small. It appears that some of the dates published for very old archaeological specimens may be suspect.

I initially thought of adding the text to the Contamination section - but as archaeology is only mentioned later in the article, I've placed it in "Use in archaeology/Interpretation". I'm aware that the new paragraph is very short and doesn't fit perfectly. I've deliberately not said that the earlier measurements were incorrect as Higham et al. is a primary source. The Supplementary Information file associated with the Higham article is 162 pages long and contains much useful discussion. The same issue of Nature also contains a News and Views article by William Davies discussing the Higham article here, and a News in Focus article here. Note that a subscription to Nature is required to view the links. Aa77zz (talk) 10:20, 21 August 2014 (UTC)