Talk:Radiocarbon dating/Archive 5

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AD or CE?

The very first edit using one of these conventions is here. And it's the BC/AD convention. Until then, editors used BP as per the usual convention with radiocarbon dating. Rklawton (talk) 18:48, 12 March 2010 (UTC)

ultra-filtration carbon dating

Does anyone know anything about ultra-filtration carbon dating? does it have its own article or a sub set of this one - perhaps by another name? This newspaper article says the technique "Perfected by scientists based at Oxford University's radiocarbon accelerator unit, it allows researchers to pinpoint the ages of ancient bones and other organic material with unprecedented accuracy." I would like to be able to link to it from Gough's Cave where bones (from 14,700 years ago) were found which have now been dated by this method.— Rod ^talk 09:54, 20 June 2010 (UTC)

It appears to be a method to reduce contamination in bone samples for radiocarbon dating, resulting in greater accuracy, see [1][2]. It works by isolating the larger pieces of bone collagen in a sample (but still very small - the second article refers to fragments >30 kDa (kilo Daltons)), giving more reliable results. Mikenorton (talk) 12:08, 20 June 2010 (UTC)

Ultrafiltration was developed at Oxford University to improve Accelerator Mass Spectrometry dating and was described by Higham, Jacobi, and Bronk Ramsey in Radiocarbon 2006, vol. 48, no2, pp. 179-195, (see abstract). A cautionary article about the claimed reduction of contamination by Hüls, Grootes, and Nadeau appeared in Radiocarbon 2009, vol. 51, no2, pp. 613-625, (see abstract). --17:44, 20 June 2010 (UTC)

Thanks both for the extra info, but I'm now convinced there is now specific article (or sub head) to link to so I've edited Gough's Cave & just linked to Radiocarbon dating. If you wanted to add anything further that would be great.— Rod ^talk 17:49, 20 June 2010 (UTC)

Hallstatt plateau

I'm a 'new page patroller', and was just looking over and making some links and portals on a new page: Hallstatt plateau. After reading 'Radiocarbon dating', I am wondering why the topic the new page claims is so important isn't mentioned here. Could someone please take a look at the new page, and either link to it or deal with it approprately if they have more information about its notability? Or, let me know and I can work on it. I'll hold off on any more 'wikifying' on Hallstatt plateau until I hear. Thanks--Nihola (talk) 18:54, 4 August 2010 (UTC)

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This was put onto my talk page, but I thought it more useful to put it here.

My take on your question is this: The article on dating dals with the method and it does mention the problem plateaus pose. If reading that article on its own you think that section needs more explanation, I might try too add some.

The Hallstatt plateau is just one of many, but it is an especially prominent and well known one. While the dating article explains the l9mits of the method, the Hallstatt one deals with the consequences of the lack of dating during those 400 years for archaeology.

Both are separate and both are adequately dealt with as far as I can see. Axel Berger (talk) 23:54, 8 August 2010 (UTC)

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If the 'dating' article you are referring to is Radiocarbon dating, then I did find this, under the calibration section:

"There are also significant plateaus in the curves, such as the one from 11,000 to 10,000 radiocarbon years BP, which is believed to be associated with changing ocean circulation during the Younger Dryas period. Over the historical period from 0 to 10,000 years BP, the average width of the uncertainty of calibrated dates was found to be 335 years, although in well-behaved regions of the calibration curve the width decreased to about 113 years while in ill-behaved regions it increased to a maximum of 801 years. Significantly, in the ill-behaved regions of the calibration curve, increasing the precision of the measurements does not have a significant effect on increasing the accuracy of the dates.[13]"

This doesn't clarify the questions that arise after reading the Halstatt plateau article. Why would changing ocean circulation create this? Why in ill-behaved regions of the calibration curve would increasing precision of the measurements not increase data accuracy? Maybe it's as simple as 'not yet known'.

If we need other pages information to understand the topic, we should make sure it can be easily located.

If something is a 'catastrophe', it should be carefully, simply and clearly explained. If I seem suspicious, it's because the article words this plateau as a catastophe, and yet also states that accurate dates can be attained by wiggle matching. How can it be both a disaster and something that can be solved by another technique? I do think clarification is needed, and I hestitate to work on this page unless it can be shown why this plateau is a 'disaster', or why the people who are being quoted as saying this felt that way. Nihola (talk) 18:22, 9 August 2010 (UTC)

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Though I think the Radiocarbon Dating article is not especially easy to understand now (too many small edits, no red thread? :-) I think your questions are already answered. However, if you(ever) consider something of the following helpful you can copy some of it to the main article.

Changes in ocean circulation can release large amounts of "old" marine CO2 into the atmosphere. This old CO2 will be incorparated by living organisms, which will reveal an older radiocarbon age than they "should". They might even have a lower C-14 concentration while they still live than their ancestors a few decades or centuries ago (and have already lost some of their initial C-14 by decay). These are the "wiggles", actually reverting the true and the apparent age.
A "plateau" appears if, over a certain time interval, the change in the atmosphere (due to production changs, reservoir exchange, etc.) BY CHANCE matches the decay-driven change in already dead organisms. All samples from this time interval will finally reveal the same radiocarbon content. If all samples yield the same measurement result independent of their age, dating is impossible (i.e. the uncertainty is the length of the plateau, 800 years for the Hallstadt, independent of the precision of the C-14 measurement). Naturally, perfect plateaus never exist, but the Hallstadt and the Younger Dryas are relatively flat.
I do not know who invented the "Hallstadt desaster". I think this was just a scientist cursing over his useless radiocarbon data from that period. The Hallstatt culture did certainly not perceive it as such. The term "desaster" should probably be omitted. Peter.steier (talk) 16:22, 13 February 2011 (UTC)

While agreeing with your last paragraph in principle, the "desaster" has been a well established and common term for decades and it is now far too late to do something about it. Axel Berger (talk) 02:55, 6 March 2011 (UTC)

New article?

I am an evolutionary microbiologist and for some reason in the past few years the number of people futilely attempting to convince me why evolution is wrong has increased. However, Irriated from having been found to be a tad ignorant on the front of carbon dating, I read it up here — nice article by the way —: I think a respectable fraction of the 1,000+ daily viewers must read it too to find the flaws in either side of this annoyingly fatuous argument. Maybe a separate article for the controversy may be good — keeping that logical/ubiased may be tricky, but it would divert attention. If it is any consolation, a small article about a kingdom in an obsolete classification system of bacteria called Monera just keeps getting POV vandalisms... --122.62.144.13 (talk) 11:40, 27 January 2012 (UTC)

I do not because i'm agree with Darwin theory, intead I think it lasts longer than what's official. C-14 dating is faulty due to climatic conditions and atomic degeneration among othe issues, as told in the article. I presume all sciences based on this method as is archeology or paleontology, fell too short dating ages. 2.138.126.148 (talk) 03:53, 19 March 2012 (UTC)

Check the section on calibration methods - C14 alone may be faulty in some (many?) cases but dates are done on things with known dates to calibrate the results and make them much more accurate, aside from cases of old wood or samples of marine origin. Most of the dating issues relating to the industrial revolution etc. are known and accounted for by things like objects with known dates. 65.128.144.216 (talk) 22:29, 8 April 2012 (UTC)

Archiving is too frequent

I think it should be more than 90 days. 6 months or 12 would be better. --Harizotoh9 (talk) 07:45, 21 February 2012 (UTC)

Maybe I was a bit hasty - was mainly going for archiving threads where discussions seemed closed. I note guidelines says archive at 50 kb and this page was only half-way there. Babakathy (talk) 09:02, 21 February 2012 (UTC)

Editing the code on this page for the bot to arhive less frequently simple, but is it suggested that some material I archived should be de-arhived? (Have no objection to this). Babakathy (talk) 13:12, 21 February 2012 (UTC)

Calibration Curve

I could not make any sense of the Calibration Curve graph, and what I did understand seemed to imply that raw radiocarbon dates overestimate actual age, which is the opposite of the truth. The graph and explanation may have been correct, but they were confusing to me. I made a new graph, based on a graph published in the new citation (same journal five years later). It is now less confusing, at least to me. Someone who knows more about this than I do should take a look at my changes. HowardMorland (talk) 14:21, 2 July 2012 (UTC)

Rewritten lede

I have attempted to simplify the lede so that people I know can understand it. This required fewer technical details (which are provided later in the article), such as references to "radiometric", "radio-isotope", years "Before Present" & 1950, etc. Ease of reading was my aim. I hope that is ok with all editors. -- spin|^control 01:22, 27 January 2013 (UTC)

Upper Age Limit - Strange explanation

Under "Measurements and Scales"

"Samples older than the upper age-limit cannot be dated because the small number of remaining intrinsic 14C atoms will be obscured by 14C background atoms introduced into the samples while they still resided in the environment, during sample preparation, or in the detection instrument. As of 2007, the limiting age for a 1 milligram sample of graphite is about ten half-lives, approximately 60,000 years.[12] This age is derived from that of the calibration blanks used in an analysis, whose 14C content is assumed to be the result of contamination during processing (as a result of this, some facilities[12] will not report an age greater than 60,000 years for any sample)."

The way this is explained does not make much sense. Why is there only worry of contamination by "C14 background atoms" in samples older than the upper-age limit? Would not this same contamination affect any sample, regardless of age? For example,: a sample actually 5,000 years old being contaminated by an influx of background carbon atoms over that time, and thus dating much older.

Also the [12] Woods Hole reference to this statement is broken. 184.153.187.119 (talk) 02:09, 29 September 2012 (UTC)

There is only worry of contamination in especially old samples because in samples that are younger than the upper-age limit, the quantity of contaminating ¹⁴C atoms is negligible compared to the surviving genuinely ancient ¹⁴C in the object. Let me give you an example: say you've got an object containing 10,000 ¹⁴C atoms. Let's say also that it's gone through a single half-life (5,730 years). If it gets contaminated by one single ¹⁴C atom, the error margin is only 1 in 5,000, or 0.02%. Now, if we put that same 10,000-atom object through ten half-lives (57,300 years), that will leave it with only about 19 or 20 atoms of ¹⁴C. If a single ¹⁴C atom then contaminates it, the error margin is now around 1 in 20, or 5% (which is often taken as a conventional upper bound on statistical significance). Thefamouseccles (talk) 06:30, 4 February 2013 (UTC)

If a sample gets contaminated by more C14, then dating would show it to be younger, not older. And also, I agree with Thefamouseccles. It is a matter of precision. The older a sample is, the wider the precision range. Vmelkon (talk) 00:35, 13 April 2013 (UTC)

¹⁴N to ¹⁴C -> 1 Electron?

What happens to the seventh electron of N14 while it turns to C14?

What happens to the 7th electron?

Aloha2009 (talk) 03:23, 4 November 2012 (UTC)

It combines with the proton produced during the reaction to make a hydrogen atom [3]. Mikenorton (talk) 09:51, 4 November 2012 (UTC)

Thank you for this information.

Can I imagine it this way?

By the way, atoms appear to be marvelous toys :-)

--Aloha2009 (talk) 19:35, 10 November 2012 (UTC)

When a neutron hits a nitrogen nucleus, a proton is ejected at high speed. It doesn't grab one of the electrons from the same atom. The carbon atom that is formed remains charged and who knows what happens to it. The proton that was ejected eventually slows down sufficiently because it encounters various atoms in its path and either binds to some atom or steals an electron from some atom. Vmelkon (talk) 22:26, 12 April 2013 (UTC)

C14 Controversy

This article lacks information about the controversy surrounding C14 dating as already published on other websites and in reference books. See, for example, http://www.answersingenesis.org/articles/nab/does-c14-disprove-the-bible .

It lacks information on it because the controversy is not genuine. It's a bunch of liars and know-nothings thinking they understand, happily claiming there's a controversy when there is none.Farsight001 (talk) 14:29, 2 November 2012 (UTC)

You might want to read these two articles as well then: http://www.answersingenesis.org/articles/cm/v21/n3/dating-dillema and http://www.answersingenesis.org/articles/cm/v22/n2/geology as well as the 28 footnotes including academic references provided for all three articles. After you've finished those, take a look also at http://trueorigin.org/dating.asp and then reply with something more credible than the unfounded attack you did last time. We should be able to agree that this Wikipedia article falls short of its true potential by ignoring scientific records, data and other facts highlighting a a credible and real controversy surrounding C14 dating. — Preceding unsigned comment added by 182.239.164.103 (talk) 20:18, 2 November 2012 (UTC)

I've read them already. They are written by the very people I was talking about in my first post above - a bunch of liars and know-nothings thinking they understand when they don't.Farsight001 (talk) 21:01, 2 November 2012 (UTC)

As an example of their idiocy, I refer you to the first article, where they say they sent a sample of a supposedly 200+million year old fossiliferous wood for C14 dating. Two big problems - real fossils have no carbon in them to C14 test with. Results would be, 100% of the time, due to contamination. Or, on occasion as creationists seem to enjoy doing, they will send in a processed and professionally preserved fossil with something like a polyeurothane sealant on the surface, in which case, the test would measure the sealant, not the sample. Second, C14, dating, as is well established by the scientific community, due to C14's decay rate, is only good up to about 60,000 years. After that, it will return gibberish results. So what moron thought it was a good idea to try to use it on something that's supposed to be 200 million years old? And what moron thought you could C14 date something without carbon in it? Only the people at AiG... Farsight001 (talk) 21:07, 2 November 2012 (UTC)

A lot of those "morons", as you call them, are professors and/or have PhD's. Look at your tone in your messages here; you are so incredibly aggressive and bitter. Doesn't that tell you something about the belief system you put your faith in? (Whether it be atheism or other). Oh, and here's another link for you which includes another long list of credible references in its 44 footnotes: http://www.christiananswers.net/q-aig/aig-c007.html . — Preceding unsigned comment added by 182.239.166.141 (talk) 06:54, 3 November 2012 (UTC)

So what? A lot of stupid and ignorant people have schooling. That doesn't change the fact that they're being stupid and ignorant. And I've seen your other article too. It, also, is based on a complete ignorance of C14 dating. I'm not being aggressive or bitter. You're just failing to grasp the extent of their ignorance. Now if you have nothing to contribute to the article, please stop wasting our time.Farsight001 (talk) 12:55, 3 November 2012 (UTC)

Arrogance and bullying are not virtues. I am contributing to the article by pointing out its key flaw as supported by numerous credible and scientifically supported articles written by experts in the field. Could you please cease this personal, vicious and bias attack which is in breach of Wikipedia's rules and is a reportable offense which has in the past led to attackers being suspended and banned. As evidenced herein, my proposition is supported by numerous credible sources such as: http://www.missiontoamerica.org/genesis/radiometric-dating.pdf for example. In your own words, "Now if you have nothing to contribute to the article, please stop wasting our time".

None of the links that you give are to reliable sources, there is no genuine controversy concerning radiocarbon dating (and why YECs concentrate on that rather than the myriad other radiometric dating techniques and things like surface exposure dating, which all give results consistent with each other, I've never really understood). I've moved this thread to the bottom of the page again as this is the norm for talk page discussions Mikenorton (talk) 13:59, 3 November 2012 (UTC)

Snelling, geologist extraordinaire PhD, found fossil "branches" preserved in situ in limestone brimming with ammonites and belemnites. All of latter obviously point to a marine environment, so what kind of wood was it? Mermaid trees? Yet instead of questioning the nature of their supposed "wood" fossil, he instead questions the nature of everything else around the rock he thinks is fossil wood. Not only that, his fossil "wood" all serendipitously preserve original wood tissue, a monumental discovery which was apparently as pedestrian to the author as merely scratching away at a few rocks... if it was real. Indeed, he doesn't even remark on the uniqueness of his discovery, merely mentioning it offhand as if Triassic and Jurassic original wood tissue was an everyday occurrence. Why do I get the feeling that Snelling either dug out some old but quite recent remnants of plant roots, if they were even plant material at all, or has deliberately been contaminating his specimens for the single-blind experiments. The latter depends on the subsequent full replicability, disclosure, and access to the original specimens for the study to maintain reliability. Peer review. None of which has been provided. And none of them ever will.

It may sound convincing to layman, but Snelling actually says nothing on how he decided it was fossil wood in the first place, nor how he arrived to such conclusions as the tree being in situ or another specimen being Dicroidium. Listen to how he identifies his specimens as fossil wood: "woody internal structure was clearly evident, thus the samples were not the remains of roots that had grown into this weathered rock from trees on the present land surface". Eh? He also conveniently fails to mention that the laboratories he sent these samples to failed to identify it as wood but iron concretions. Neither does he actually provide the detailed results of the labs, instead merely letting readers take it on good faith that this was the conclusion. His assurances of the lack of contamination is not backed up even by a description of the original deposition, how he collected the "fossils", preparation, etc. Everything is hurriedly mentioned and quickly dismissed. Pretty words, vacuous information content. Notice that the pictures provided are also mere thumbnails discouraging closer inspection.

He also uses real academic studies for his factual enough introductions. Then deceptively weaves it around creationist journals and biblical references while using big science words. Common strategy. If it was Wikipedia, it would have been known as WP:SYNTHESIS and source padding. Akin to referencing NASA in describing Mars, but then suddenly switching to UFOlogists with crystals and claiming that Mars is inhabited by three-foot green men living in invisible palaces. Hoping that the reader will see you used reliable NASA information and subsequently conclude that all your other references are similarly reliable when they are in fact, not. His conclusions are breathlessly repeated by various religious sites only, especially ones he controls which also sing praises to his glittering career. None of which justify your characterization of his studies as "scientifically supported".

Real science looks for answers, even if it means rejecting obsolete ones. Modern geology and paleontology has undergone several shifts from earlier versions as more information has been gathered. Mistakes have been made, acknowledged, and corrected.

Creationism, in contrast, has not and never will. How could they? They already have an answer decided arrogantly in a ~4000 year old book by an anonymous goatherder to be absolute truth. An inviolable answer that they are forbidden from proving wrong. It's not a search for answers. It's a search for excuses. -- OBSIDIAN†SOUL 15:56, 3 November 2012 (UTC)

To 182.239.164.103: You need to know that all creationary sources are by definition unreliable sources simply because they are creationary sources and so cannot be used on WP. HerbertHuey (talk) 22:21, 3 November 2012 (UTC)

I thought Wikipedia claimed to have a No Point of View Policy and one would think that with so much debate surrounding the topic and across so many credible sources that a section titled Controversy Surrounding C14 Dating would make this page more credible than presenting a blatantly bias point of view which only promotes ignorance in the wider community. See http://creationwiki.org/Carbon_dating . — Preceding unsigned comment added by 219.90.244.129 (talk) 02:11, 4 November 2012 (UTC)

No, wikipedia has a neutral point of view policy. It means that we reflect the consensus of reliable secondary sources. As a result, a bunch of morons blovating and basically flat out lying about a subject they are clearly not experts on would not make the page more credible, but less credible.Farsight001 (talk) 02:52, 4 November 2012 (UTC)

RealTalk1000 (talk) 17:01, 5 December 2012 (UTC)

Quite a high-minded academic debate going on this Talk section here.

Those who propose a dissenting argument on a subject are stupid, idiot, poo-poo heads? End of debate? Please...

I am a Political Scientist and would label such methods of shutting down communication and debate among two individuals "religious zealotry" and "dogmatic".

For the record, my point of view on this subject is as follows: I was taught throughout the years in school that carbon dating is accepted consensus scientific view, and therefore my default viewpoint has been to accept this as truth.

I cannot speak to whether or not there is an actual scientific debate on this issue or not. I have no clue. I have expertise in Project Management and in the Social Sciences, not the Physical Sciences. Yet while I can not speak for a scientific debate, I will definitely assert that there is a debate among people and in our society on this issue. The social controversy is real, the social debate is real, and denying this fact is illogical and a denial of reality.

There are social controversies on, for example, the Indian/Pakistani border. While there is no controversy on this issue in the scientific community, it is a very real social controversy. Is it Wikipedia's policy to ignore the controversy altogether and act like it does not exist? Any individual who would like to read commentary and happenings of a social controversy are denounced and insulted? I would hope not.

There is a respectable man in my city council who brought up this controversy to me at lunch the other day. I simply came to visit the wikipedia page to find out the credibility. Instead of informing me, wikipedia was silent. Rather, this Talk page the debate was full of insulting language towards a person with an opposing viewpoint. I am college educated, but like most people, I am rather unlearned and untrained in the Physical Sciences. In my ignorance on this subject, this whole ordeal has simply made me rather suspicious of wikipedia as actually being riddled with bias, censorship, and unprofessional amateurs armed with school-yard insults. As opposed to a place of high-minded, civil discourse and academics.

I think most would consider what I have just stated as sound reasoning, and therefore the social controversy on carbon dating should be addressed by wikipedia authors. My proposal to deal with it, is as follows:

The goal of the proposal is essentially twofold:

1) Allow wikipedia vistors to read an article on this carbon dating debate featuring all sides of what appears to be a social controversy, and restrain ourselves from Censorship.

2) At the same time, we want to preserve the scientific integrity and credibility of Wikipedia. We would not want to misinform people and feature quack science that does not meet or exceed a certain standard.

To accomplish this:

The social controversy should possibly have a separate article as suggested above by another contributor, so as to not upset the credibility of the scientific article. The proposed article should discuss the different viewpoints. Issues discussed would include the credibility of the science or lack thereof, and if there is indeed an actual scientific controversy that even exists.

I am unfamiliar with wikipedia's standard on publishing what is considered credible science, but if the controversy ends up meeting or exceeding the standard, than no doubt the scientific controversy should make its way into this carbon dating article.

Is this proposal out of line or is this quite reasonable?

RealTalk1000 (talk) 17:01, 5 December 2012 (UTC)

You come here and to other talk pages only to push your agendas (due to boredom I am guessing, and with the mistaken view that this is a debating society or something), and then lament the fact that no one takes your flame bait. You have absolutely no edits (as in zero), yet you go about insulting the editors. You have exactly as much credibility as anyone else with a pulse and an internet connection; you admit you come here only to shake things up, but yet moan when no one takes your flamebait. Give it a break, because as I am proud to point out, no one is biting. Marteau (talk) 07:09, 11 December 2012 (UTC)

An editor dismissing the creationist POV here is being extremely uncivil, but he also happens to be correct. There is no serious dispute among genuine experts, and to include the religious dissent in a page about the scientific process would be giving it undue weight, violating Wikipedia's NPOV policy. I suggest reading Wikipedia:Neutral_point_of_view, particularly the sections on Due and Undue Weight, Making Necessary Assumptions, and Controversial Subjects. It may also help to see Wikipedia:Identifying_reliable_sources, particularly the guidelines in the Scholarship section. If you disagree with any of those standards, feel free to argue for a change on the talk pages for those articles. Unless the standards change, however, they're set at a higher level than this article, so arguing about it here is an entire waste of time; no matter what argument you make, changes based on creationist sources will be reverted. Elmo iscariot (talk) 13:53, 30 April 2013 (UTC)

Thank you, Real Talk, for your support. You actually get my point, unlike everyone else on hear - that a scientific source cannot claim to be credible through arrogance and bullying, and that there is actually a scientific debate here which cannot be denied or ignored. Related to this topic, read "Evolution Impossible" by Dr. John F. Ashton. Dr. John Ashton is Adjunct Professor of Biomedical Sciences at Victoria University, Melbourne, and Adjunct Professor of Applied Sciences at the Royal Melbourne Institute of Technology (RMIT) University, the largest Australian tertiary institution. He holds a BSc (Honors) with prize in chemistry and PhD in epistemology (a branch of philosophy dealing with the limits of knowledge), also with prize, from the University of Newcastle and an MSc in chemistry from the University of Tasmania. Dr. Ashton is a Chartered Fellow of the Royal Australian Chemical Institute, and a former Honorary Associate in the School of Molecular and Microbial Biosciences at the University of Sydney. — Preceding unsigned comment added by 182.239.167.47 (talk) 00:44, 16 May 2013 (UTC)

Elmo iscariot has correctly pointed out the two key policies that should be understood in this context. If there is a specific statement from Ashton that is relevant, show that the source qualifies as a reliable source and suggest it here. But please first check if its something that's already been debated and discussed above. For example, the main issue in his Ch10 has been explained clearly above. Babakathy (talk) 05:46, 16 May 2013 (UTC)

Some criticism.

There is one fact that makes it highly unreasonable to believe that the proportion of C-14 to C-12 was the same in the past as it has been in recent history: It is not in equilibrium.

The rate of C-14 production today is 18% higher than the rate of decay (Whitelaw). This means that today we are experiencing a net increase in the proportion of C-14 in the atmosphere. It is impossible to determine whether it has always been increasing (as argued by some creationists) or whether it has undergone cycles of increase and decrease (as argued by other creationists and evolutionary scientists). But one thing is certain: there is no reason to believe that the C-14:C-12 proportion has been constant throughout time, and good reason to believe it has been different, and often lower, in the past than it is today.

If the C-14 content of the atmosphere was lower in the past, that means that Carbon dating results today are inflated, because the calculations will mistake the absence of C-14 in the original sample as years which passed by causing the C-14 to decay.

Recognizing this, many uniformitarian scientists calibrate their dating efforts to the early 19th century, in the belief that today's C-14 increase is due to the industrial revolution. This assumes, however, that today's C-14 increase is only the result of the industrial revolution (which is unfalsifiable) and that the proportion was in equilibrium prior to the 19th century (which is also unfalsifiable). In other words, while acknowledging the problem posed by the increasing C-14, the uniformitarian scientists have failed to solve it, and yet continue to use the methodology. 76.120.17.197 (talk) 19:14, 13 April 2013 (UTC)

We know all this already, and those who do C14 testing compensate of these things when they do the math. So scientists have no failed to solve it. You just don't have a clue.Farsight001 (talk) 21:07, 14 April 2013 (UTC)

Agreed. 76.120.17.197: the section "Calibration" in the article addresses the issue. Zero^talk 15:37, 30 April 2013 (UTC)

What is a evolutionary scientist? Scientists who study evolution? They don't deal with radiocarbon dating since it is too limited. What is a uniformitarian scientist? I have no clue. The industrial revolution didn't cause an increase in C14. That is just none sense. The nuclear age caused an increase in 1945 and onwards when nuclear weapons were tested since various isotopes are generated when a uranium or plutonium atom splits. Therefore, during those time periods there was a burst of C14 in the environment. Yes, obviously the production of C14 in the upper atmosphere isn't constant. I think A LOT of people have A LOT of opinion on the subject due to religious reasons. That is why you are here. Vmelkon (talk) 01:48, 6 July 2013 (UTC)

C-14 production dependent on geomagnetic latitude/carbonic acid production

I'm about to cut down these two sentences:

The highest rate of carbon-14 production takes place at altitudes of 9 to 15 km (30,000 to 50,000 ft), and at high geomagnetic latitudes, where C-14 then reacts relatively rapidly with oxygen to form carbon dioxide (CO2). The carbon dioxide containing the C-14 species spreads evenly throughout the atmosphere and the oceans, reacting with water to produce carbonic acid (CO2 + H2O → H2CO3).

I can't find a source for the statement that the production is higher at high geomagnetic latitudes, though it seems sensible enough; if anyone has a good source for this please re-add it or leave a note here. I'm also going to cut the comment about carbonic acid; that's not really relevant to the topic -- just saying "dissolved" seems enough to me.

If I have time I'm going to work through the article as far as I can get with a view to cleaning up and tightening, and perhaps going for Good Article status eventually. Any comments or assistance would be welcome. Mike Christie (talk - contribs - library) 01:49, 17 July 2013 (UTC)

Explaining the use of the Libby half-life

I've added this sentence: "This approach has the advantage of maintaining consistency with the early papers, and also avoids the risk of a double correction for the Libby half-life value." I'd like to point out that quoting radiocarbon years has the additional advantage that changes in calibration can be applied easily; essentially the radiocarbon date is the raw data that will not change as calibration improves, so it's the number that should be made available for future re-analysis. However, I can't find a source that makes this point. Is this sufficiently obvious that we don't need a source? Or does someone have a source we could use? Mike Christie (talk - contribs - library) 13:13, 20 July 2013 (UTC)

Use of template:chem

Recent edits have removed some occurrences of the template {{chem}} and added a lot of direct formatting. For example {{chem|14|C}} replaced by <sup>14</sup>C. It makes the formatting inconsistent. Was this done for a special reason? −Woodstone (talk) 17:14, 21 July 2013 (UTC)

I took out some examples of {{chem}} because of the line spacing problem -- see here for a discussion. I only did the ones on the text I was working on, since I'm planning on working my way through the whole article; I figured I'd get to the others later. If others think {{chem}} is better than using superscripts/subscripts I'll go along with the consensus, but I do think it makes a paragraph look ugly. Mike Christie (talk - contribs - library) 17:33, 21 July 2013 (UTC)

In the subtemplate in {{su}} of {{chem}}, I have changed the default sub/superscript size to 70%, eliminating the extra line spacing. Also fixed passing the fontsize parameter, in case this appears too small for other applications. −Woodstone (talk) 09:01, 22 July 2013 (UTC)

Thank you. Fixing the template is better than simply removing it. The template makes it trivial to find chemical formulae in a page's source, allows formatting to be uniformly changed without manually searching out each occurrence, etcetera. There are many cases where people overuse templates, this is not one of them. This is exactly the situation where templates should be used.  —Sowlos  10:05, 22 July 2013 (UTC)

I've switched everything back to using {{chem}}; thanks for the fix. Mike Christie (talk - contribs - library) 10:50, 22 July 2013 (UTC)

The change to the general purpose {{su}} was reverted. I have now implemented the change directly in the special case of {{chem}}.−Woodstone (talk) 07:52, 23 July 2013 (UTC)

Removed section on in situ production and production at altitude

I just took out a paragraph on local variations caused by altitude and varying field strength. The citations are from 1958; the article now includes text citing more recent sources on both in situ production and latitudinal variation, both of which say the effect is negligible. Bowman also says that the altitude effect is negligible; I'll add that shortly. I think the more recent sources indicate that we don't need to reference the 1958 papers any more. Mike Christie (talk - contribs - library) 11:56, 26 July 2013 (UTC)

Methods

What does a negative pressure (-25psi) mean? Without some context (such as this possibly being a differential pressure between the two tubes) the statement has at best little, and likely, no meaning. Vacuum has an absolute floor. I propose striking this part of the methods section. Dan Watts (talk) 16:56, 29 July 2013 (UTC)

I'm fine with cutting it. Mike Christie (talk - contribs - library) 23:22, 29 July 2013 (UTC)

The effects of human activity

The section starts with "Fossil fuels, such as coal and oil, have no detectable ¹⁴C; they are so old that almost all the ¹⁴C has decayed." while http://geology.gsapubs.org/content/19/3/253.abstract purports ¹⁴C ages of petroleum that "range from 4240 to 5705 B.P." Perhaps a less fixed stance is warranted. Dan Watts (talk) 13:24, 30 July 2013 (UTC)

I've reworked that paragraph a bit, and added a bit more information. I was misrepresenting the source slightly; it only said that coal was that old, though the other source I've now added makes the same claim for oil. I think it's clear that oil young enough to have detectable ¹⁴
C is unusual; I could add something to that effect in a footnote, but I'm not sure it's necessary. Mike Christie (talk - contribs - library) 23:34, 30 July 2013 (UTC)

Switching some specialist refs to survey texts

There are a few references that seem like overkill to me; for example, citing:

McNichol AP, Schneider RJ, von Reden KF, Gagnon AR, Elder KL, NOSAMS, Key RM, Quay PD (October 2000). "Ten years after - The WOCE AMS radiocarbon program". Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms 172 (1–4): 479–84. Bibcode:2000NIMPB.172..479M. doi:10.1016/S0168-583X(00)00093-8

for the statement:

When CO2 is transferred from the atmosphere to the oceans, it initially shares the 14C concentration of the atmosphere. However, turnaround times of CO2 in the ocean are similar to the half-life of 14C (making 14C also a dating tool for ocean water).

This is a commonplace statement, and I think the reader is better served by having this referenced from a survey book like Bowman or Aitken, or from a college textbook -- something a reader is reasonably likely to have access to, instead of a journal or more obscure reference. I'm going to change these where it's convenient to do so; if someone doesn't think this is a good idea, please say so. Mike Christie (talk - contribs - library) 22:10, 1 August 2013 (UTC)

Removing section on ISGS details from 1973

There's a section on methods partly referenced to Coleman, Dennis (1973). "Illinois State Geological Survey Dates IV". Radiocarbon. 15 (1): 75–85. {{cite journal}}: |access-date= requires |url= (help), which I am about to cut. It's very specific to one particular preparation method, and is only partly sourced. I doubt if we would go into that much detail unless we had pages of information about methods. If we get to that ponit we can consider re-adding this, but I would rather use a methods handbook (such as Gillespie's Radiocarbon Users' Handbook) that discusses different approaches than pick a description of a setup from a single source. Mike Christie (talk - contribs - library) 22:23, 4 August 2013 (UTC)

Also removing this: Wang, Hong (8). "Pyrolysis-combustion 14C dating of soil organic matter" (PDF). Quaternary Research. 60: 348–355. Bibcode:2003QuRes..60..348W. doi:10.1016/j.yqres.2003.07.004. Retrieved 2012-04-23. {{cite journal}}: Check date values in: |date= and |year= / |date= mismatch (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help) since it is used to cite only a fairly obvious fact; however, if someone has access to it I would be interested to see if it contains anything else about soil dating that could be used for this article. Mike Christie (talk - contribs - library) 22:23, 4 August 2013 (UTC)

If you send me email, I'll give you a copy. Zero^talk 00:20, 5 August 2013 (UTC)

Done; thank you! Mike Christie (talk - contribs - library) 00:57, 5 August 2013 (UTC)

And received; thanks again. It's a review of a new method of dating soil by splitting it into two components via pyrolysis. The results are interesting but probably too specialized for this article; I suspect that by the time this article is done it will be too long and will have to be split via summary style. The sub-article on measurement methods would be a good place. I did also notice that the sentence that was included here was a direct copy of the first sentence of the article, so we'd have had to remove it anyway as a copyvio. Mike Christie (talk - contribs - library) 01:21, 5 August 2013 (UTC)

Question about current accuracy of AMS vs. beta counting

In Science-based Dating in Archaeology, Aitken says "...for the present at any rate, the highest precision of all ((± 0.25% or better, corresponding to less than ±20 years in age) is obtainable by beta counting -- in one of a few special high-precision laboratories." This is from 1990, so I don't know if it's still true. The Belfast lab, one of the most accurate in the world, now uses AMS, so I suspect it's no longer the case that beta counting can outperform AMS. Does anyone have a source that addresses this? I don't think it's worth putting in unless we have a more recent source, since Aitken makes it clear ("for the present") that it might change. Mike Christie (talk - contribs - library) 15:07, 10 August 2013 (UTC)

Also posting this to Wikipedia talk:WikiProject Science. Mike Christie (talk - contribs - library) 15:09, 10 August 2013 (UTC)

This review indicates that it is a matter of sample size. Beta counting is still more precise for large samples, but for tiny samples beta counting is useless. Zero^talk 15:17, 11 August 2013 (UTC)

That's a very useful source; thanks for that link. It has some survey-type comments that I think will be usable in the article. Re precision: he says "Beta counting labs probably can still claim, at their best, to generate dates with smaller errors than AMS labs (although the gap is closing quite fast)–but any further improvements in the future will surely be made by AMS labs" so as you say, it was still the case in 2000 that beta counting is better, but as with Aitken he indicates the likelihood that that will change. Still, 2000 is recent enough that I think we can use the statement in the article, with an "as of" qualifier, until we find a more recent source commenting on this. Mike Christie (talk - contribs - library) 15:39, 11 August 2013 (UTC)

British spelling?

I'm about to revert a couple of spelling changes (artefact/artifact) on the grounds that this article is in British English. I looked at the version of the article just before I began editing it and the only evidence I can see there is the choice of realise over realize, so I'm picking British. If anyone thinks that isn't the right choice, please say so. Mike Christie (talk - contribs - library) 10:41, 2 October 2013 (UTC)

Fractionation

There must be some kind of error. The formula clearly indicates the more ¹³C in a sample the higher the δ 13 value. But the text somehow describes the opposite. Also the sentences are wrong: "Measured δ 13 C values for marine plankton range from −10‰ to −31‰" should be written like this: "Measured δ 13 C values for marine plankton range from −31‰ to -10‰". Or am I missing something here?? --178.197.226.139 (talk) 14:24, 3 November 2013 (UTC)

Can you give an example of where the text seems to contradict the formula? It's a confusing area and I may have made mistakes in the text. I agree on switching the order of the terms and will do that later today if you don't do it first; I thought it would look odd that way but in fact it's misleading to have it the way it currently is. Mike Christie (talk - contribs - library) 14:37, 3 November 2013 (UTC)

The problem is caused by the term "fractionation". Does it mean a higher or lower δ 13 value? If it means a higher value, the text is wrong, e.g. "Under these conditions, fractionation is reduced, and at temperatures above 14°C the δ 13 C values are correspondingly higher, reaching −13‰. At lower temperatures CO 2 becomes more soluble and hence more available to the marine organisms; fractionation increases and δ 13 C values can reach −32‰." Here the δ 13 value decreases (from -13 to -32‰) but the fractionation increases, that's quite strange. I would say that more fractionation means a higher δ 13 value, so the δ 13 value should go up from -32 to -13‰. Actually I just checked the mathematical formula but I'm no biologist, so I won't edit the article. --178.197.236.230 (talk) 18:12, 3 November 2013 (UTC)

Just a hint: the formula is not "delta"-negative (e.g. y = -x), it just contains a "-1" that makes the absolute value negative (e.g. y = x - 1), but not the changements of the value (see @derivation). So an increase in ¹³C always means an increase in δ 13. And since we are in negative numbers, we get such an increase e.g. from -32 to -13. It's quite similar to the negative values of the decibel unit. Hope this helps. By the way, the trick with any mathematical equation is to draw it in the cartesian coordinate system, then you'll immediately understand it...and after a while you can draw it in your head. Math is so easy if only the teacher would understand to teach math the same as it was invented by Descartes, Leibniz et al: Just by drawing. We should learn to draw functions at the age of 10, then we'd all be mathematical geniouses at 20. ;) --178.197.236.230 (talk) 18:36, 3 November 2013 (UTC)

Fractionation refers to ¹³C being taken up in a process less readily than ¹²C, so if there is more fractionation in a process, the result is less ¹³C, or a more negative (lower) value for δ¹³C. When fractionation is reduced, ¹³C is taken up faster, and there is more of it, so the δ¹³C is higher. -13‰ is a higher value than -32‰, so I think the confusion stems partly from having the ranges written the wrong way round, as you pointed out. I've fixed that -- does that help?

Clearly this is a difficult paragraph to follow, so I'll think about ways to rewrite it more clearly. Mike Christie (talk - contribs - library) 22:10, 3 November 2013 (UTC)

Keenan, Calibration of a radiocarbon date

I just removed a mention of a statistical critique of current methods of deriving calibrated dates from radiocarbon dates. I contacted the paper's author, Douglas Keenan, who told me there has been no response to the paper in the peer-reviewed literature. The paper looks like it might be a significant contribution but I don't think we can include it here until there is more discussion of the result in reliable sources. Mike Christie (talk - contribs - library) 16:56, 3 January 2014 (UTC)

While I'm not proposing to put it back at the moment, I question your justification. The paper itself is in the peer-reviewed literature and I don't see why waiting for a published response is required. That is not a standard criterion in wikipedia. Zero^talk 01:01, 4 January 2014 (UTC)

Fair enough. Here's what I was thinking. The paper argues that one of the key modern statistical techniques is flawed. The rest of the community appears to be continuing to use that technique without paying any attention to the criticism. Including mention of a single paper that has drawn no response despite a significant claim seems to me to be undue weight; there are thousands of papers each year that relate to radiocarbon, and I think it's best to include only topics that are covered in secondary sources. Once the decision is made to cover the topic then papers can be cited but this is a claim with no coverage at all as far as I can tell. In addition, it's not yet clear how dramatic the effect is -- the real impact seems likely to be on Bayesian analysis but the paper doesn't give examples of Bayesian analysis giving different results. (I plan to ask Keenan about that, and may be able to get a data set from an archaeologist I know to try running it through his analysis, but of course nothing I get back will count as an RS.) Mike Christie (talk - contribs - library) 04:18, 4 January 2014 (UTC)

Ok. Zero^talk 05:21, 4 January 2014 (UTC)

Speleothem Science?

Does anyone have access to Speleothem Science by Fairchild and Baker? I can see enough of it on Google Books to guess that it would be a good source for how speleothems have been used to extend calibration curves, and for the accuracy of the most recent work which has helped in extending the INTCAL curves. Mike Christie (talk - contribs - library) 00:52, 2 January 2014 (UTC)

Send me mail (link at my home page). Zero^talk 06:11, 4 January 2014 (UTC)

Done; thanks. Mike Christie (talk - contribs - library) 13:20, 4 January 2014 (UTC)

Suess's curve

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? Zero^talk 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. Zero^talk 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. Zero^talk 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)

Parenthesis?

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 (talk • contribs)

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. Zero^talk 00:38, 9 May 2014 (UTC)

Recent undo

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)

Next steps for the article

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 [4] 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)

Revised list of next steps

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

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)

cal BP

Neither this article nor the article Calibration of radiocarbon dates mentions the abbreviation "cal BP", also written as "calBP". Is it standard? I have seen it often. Also, does the "cal" stand for "calibrated" or "calendar (years)"? Both interpretations are possible and make sense, after all. Is there an "official" expansion? Any statement in the literature? --Florian Blaschke (talk) 20:21, 6 November 2014 (UTC)

Yes, it should be included. My understanding is that "cal BP" means "calibrated age expressed in years before AD 1950". There is also "cal kyr BP" which is the same but expressed in thousands of years. Zero^talk 22:17, 7 November 2014 (UTC)

I've added a sentence about this to the section "Reporting dates". Mike Christie (talk - contribs - library) 23:26, 17 February 2015 (UTC)

Planning to take this to FAC

I am planning to nominate this as a featured article candidate some time in the next month or so. I am going through Taylor & Bar-Yosef's Radiocarbon Dating to see what changes need to be made, but so far have found little that needs to be updated. I've also asked another editor to do a copyedit; and I'll wait till the section naming question is settled before nominating. I've asked three archaeologists, including a radiocarbon specialist, to look over the article and comment, and I've had some useful feedback from them; I may still get a little more off-wiki. Is there anything else that looks to be necessary before a nomination? Mike Christie (talk - contribs - library) 23:50, 17 February 2015 (UTC)

References should be called References, not Footnotes Suggestion

The article's headings can be a named a number of different titles, but it should match the common naming for science articles since this is an important article. According to the Council of Science Editors, the list of works cited should be called "References". The list of books should be called Bibliography. Frmorrison (talk) 20:55, 17 February 2015 (UTC)

I brought this up at the PR. I also think "References" would be better than "Footnotes" - and having both "Notes" and "Footnotes" seems very odd to me. Aa77zz (talk) 21:57, 17 February 2015 (UTC)

I prefer the existing titles, but if nobody else comments in a few days then I've no problem with changing them. Is there a consensus on WP anywhere about this? I've mostly written humanities articles so perhaps that's why the current titles look more natural to me. I can see the point re "Notes" and "Footnotes"; I've seen this done as "Notes" and "Citations" (e.g. at Middle Ages) and as "Endnotes" and "Notes" (can't quickly find an example). Looking through FAs for both science and humanities articles I see a great deal of variation on these headings. I'm used to seeing "References" as the list of sources used in an article; what I don't like about "Bibliography" is that in cases where the subject of the article has published works, that's the natural title for a section listing them. Mike Christie (talk - contribs - library) 23:19, 17 February 2015 (UTC)

You could name the current "References" section "Further reading" instead. — Preceding unsigned comment added by Frmorrison (talk • contribs) 15:43, 18 February 2015 (UTC)

Limited Test Ban Treaty

Ref. 29 was: "Limited Test Ban Treaty". Science Magazine. Retrieved July 26, 2013. but the url pointed to [5] - a web page entitled "Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water" from the US Department of State. This seems a solid source. I've changed the cite to this page. Aa77zz (talk) 13:52, 27 February 2015 (UTC)

Et al.

I noticed this edit to Radiocarbon dating: [6] and the accompanying edit summary. I just want to point out that, according to WP:Manual of Style#Miscellaneous shortenings, "et al." should only be used in references and should not be italicized. See the table in "Miscellaneous shortenings" and compare to cf. and viz., which are italicized. CorinneSD (talk) 15:13, 27 February 2015 (UTC)

Thanks for pointing this out. I've now removed the italics from all the "et al." and substituted "coworkers" in the body of the article. I struggled to follow your MOS link but found it on different page: WP:Manual of Style/Abbreviations#Miscellaneous_shortenings. Aa77zz (talk) 15:47, 27 February 2015 (UTC)

Archaeology

I see this edit to the Archaeology section, second paragraph in the Interpretation sub-section: [7]. I'm glad et al. was changed back to "et al.", but "coworkers" should be "co-workers". However, I thought before I change it I would ask whether "colleagues" might be more appropriate here. It depends upon the particular relationship between Higham and the others. CorinneSD (talk) 16:54, 27 February 2015 (UTC)

If you prefer "co-workers" please go ahead and change the article but I believe both forms are acceptable - for example see the Merriam-Webster definition here. I don't have a strong preference. To me the word "colleagues" implies that the authors are from the same institution and work together. Note that the Nature article has a large number of authors that come from many different institutions. It is very likely that they don't all know one another. Aa77zz (talk) 17:36, 27 February 2015 (UTC)

Regarding "coworkers" vs. "co-workers", it may be true that both spellings are acceptable, but I think "coworkers" slows the reader down because he or she has to figure out that it's "co" and not "cow", so I much prefer the hyphenated spelling. Regarding "colleagues", a colleague can simply be a person who works in the same field. See [8]. The main definition is, "an associate in a profession or in a civil or ecclesiastical office". Sometimes, people who work in the same profession but in different institutions/universities collaborate on research and on writing and publishing the results. They would be colleagues. A co-worker would be a person who works in the same company or organization, regardless of the position that each holds. - CorinneSD (talk) 20:42, 27 February 2015 (UTC)

I've added a hyphen. I also considered "collaborators" but this term may not be appropriate for the three co-authors that work in Higham's lab. Aa77zz (talk) 21:27, 27 February 2015 (UTC)

Two Creeks

Seems there is a problem, an error in the reference. Two Creeks Buried Forest State Natural Area is in Wisconsin on the west shore of Lake Michigan. However the reference states Two Creeks, Minnesota, (USA), a locality on the western shore of Lake Michigan Taylor & Bar-Yosef (2014) p. 35. As it is an obvious error, I'll change it & make the link blue. Vsmith (talk) 12:56, 14 March 2015 (UTC)

About to go get on a plane, but the source does say Minnesota -- I double-checked. I'll see if I can find the original paper when I get back. Looks like my secondary source is in error. Mike Christie (talk - contribs - library) 13:42, 14 March 2015 (UTC)

Precision, precision!

An otherwise excellent article is spoiled by a poor treatment of precision. According to the article carbon-14 the half-life of ¹⁴C is 5730 ± 40 y. The magnitude of the ± figure is important because it limits the number of significant figures that are meaningful. In the case of t_½ this shows that the last digit (0) is not known with any certainty. Therefore a maximum of four significant figures may be shown; three would be better In the equation

$t=8267\cdot \ln(N_{0}/N)years=19035\cdot \log(N_{0}/N)years$

19035 has too many sig. figs. and, arguably, so does 8267.

I assume that ± 40 represents one standard deviation, a measure of the precision of the measurement. Check? I am surprised that in this day and age the value is still so high (0.74%). Be that as it may, the significance of the figure is how it impacts on the error in dating. As the date gets older its precision of its measurement decreases. This is what puts a limit on the age that can be determined. One could use error propagation to calculate when the error would reach 100%, say, of the value.

In summary, radiocarbon dating is a quantitative technique. All quantitative measurements are subject to experimental error and this should not be glossed over. Petergans (talk) 16:10, 8 July 2015 (UTC)

@Petergans: I follow your reasoning, but the sources I have use these figures, and I'm hesitant to change them without a source. Searching for "19.035" and "radiocarbon" in Google Books shows that this is the figure that appears to be generally used. Mike Christie (talk - contribs - library) 11:53, 15 July 2015 (UTC)

Is the lead too long?

G8j!qKb just added a tag to this article indicating that the lead needs to be shortened. I've read through the lead a couple of times, and with the exception of the sentence that Aa77zz has already removed I don't see anything that seems excessive. It's certainly a long lead, but it's a complicated topic and I think the current lead is appropriate. I'd like to get other opinions here; any comments from other editors of the article? Mike Christie (talk - contribs - library) 14:25, 23 July 2015 (UTC)

The lead breaks the rule in WP:LEAD that it should be no more than four paragraphs, but that is a matter of arrangement rather than length. I would leave out the definition of BP, which is a technical point not specific to radiocarbon dating. The last paragraph seems to me unsatisfactory on re-reading. It mentions the minor matter of the Turin shroud but not does not give examples of key dates which have been established for the first time. As it is mentioned below, the start of the Holocene would be far better choice in my view. Overall, I do not think the lead is too long. Dudley Miles (talk) 16:56, 23 July 2015 (UTC)

I'd like to get other opinions on both points. Johnbod suggested that the lead explain how dates are presented, which is why I added the definition of BP. The mention of the shroud of Turin is more to point out that the method sometimes gets applied in situations of popular interest than to give an example of a scientifically important application -- I think it would be hard to do justice to e.g. the Two Creeks example in a single sentence in the lead. Mike Christie (talk - contribs - library) 12:55, 25 July 2015 (UTC)

I did not mean mentioning Two Creeks. I would suggest something like "Radiocarbon dating has allowed key transitions in prehistory to be dated, such as the end of the last ice age, and the beginning of the Neolithic and Bronze Age in different regions."

I like that formulation. If nobody else comments here in the next day or so let's make that change. Mike Christie (talk - contribs - library) 15:05, 25 July 2015 (UTC)

I've never liked the reference to the Turin shroud in the lead and I'm happy with the proposed replacement. The definition of BP is a technical detail that could easily be omitted from the lead. Aa77zz (talk) 17:17, 26 July 2015 (UTC)

I've made the first change. If nobody else comments we can cut the BP sentence too, though I think Johnbod had a point when he said that the definition of the date notation is one of the things that people will come to the article looking for. Mike Christie (talk - contribs - library) 21:56, 26 July 2015 (UTC)

No further comments, so I've cut the BP definition. Mike Christie (talk - contribs - library) 12:26, 28 July 2015 (UTC)

Not everyone is convinced ..

"Radioactivity did not exist in earlier times and could not therefore be discovered. It has only existed for a few thousand years, because now the atoms split up more and more."

Rudolf Steiner, 1905-10-05 — Preceding unsigned comment added by 87.66.108.229 (talk) 19:10, 6 July 2015 (UTC)

I think you'll need a better source than a mystic, philosopher, social reformer, architect, and esotericist (to quote our article) - he was clearly not a physicist. Mikenorton (talk) 19:17, 6 July 2015 (UTC)

Claiming that radioactivity did not exist in earlier times is like claiming that gravity did not exist in earlier times; or magnetism, or chemical reactions. It's simply a silly statement. BeŻet (talk) 10:23, 8 July 2015 (UTC)

Is this for real? That people actually embrace such absolute nonsense in this day and age is utterly astonishing. An American colleague recently told me that well over 25% of his countrymen actually believe that the earth is <= 6000 years in age. That is simply amazing. To be fair, in my own country, we certainly have our fair share of those who are not terribly well educated, at a rate of occurrence which is probably quite similar to theirs, but I think that ours mostly just sit around and complain about the weather or talk about car parts and such, not embrace superstition and mysticism to such a degree.

I think it might be time to join the rest of us in the 21st century. — Preceding unsigned comment added by 208.103.255.174 (talk) 18:34, 21 September 2015 (UTC)

Recent changes to date format

User Frozenprakash recently changed the date formats in some places in the article to CE rather than AD. I reverted, citing WP:BCE, and Frozenprakash reversed my revert, levaing a note on my take page that the Common Era article provided support for changing the date formats to CE. I'm inclined to prefer the AD format, given that that's what I see in the sources. Any comments from others? Mike Christie (talk - contribs - library) 11:20, 3 September 2015 (UTC)

Agreed that it should stay as it was - I've reverted again. There needs to be a compelling reason to make this change. Mikenorton (talk) 11:36, 3 September 2015 (UTC)

Agree with Mikenorton. Corinne (talk) 22:13, 3 September 2015 (UTC)

Article should be BCE, since this isn't an article about Christian calendars. ldvhl (talk) 00:56, 4 September 2015 (UTC)

True, All the scientific notation uses BCE/CE rather than BC/AD, which is quite secular and not related to christian calendar. Even all the notations from recent major science magazine shifted to BCE/CE format from BC/AD quite a couple of years ago, so i hope apart from christian history and cultural stories, at least in the scientific articles the more secular and more common BCE/CE notations should be used.
Frozenprakash (talk) 05:06, 4 October 2015 (UTC)

Recent IP edit re brackish waters

I just undid this edit, which added a sentence about brackish bodies of water such as the Black Sea and the Baltic Sea having "relatively younger river runoff water". I don't think this should stand as is, partly because no source was given when it was added, but mostly because there are cases where the river water has less 14C, rather than more. This can happen where the river water contains leached carbonates, for example; Taylor and Bar-Yosef explicitly mention this as a possibility (pp. 130-132) and say that in general each lake environment and coastal area should be evaluated independently as there can be a good deal of variation. I don't think the general statement added is precise enough; if something along those lines is worth adding it should mention the caveats, and of course it should be sourced. Mike Christie (talk - contribs - library) 19:16, 10 January 2016 (UTC)

Maximum age under 4400 years

I just undid this edit; the edit summary said that it was meaningless to refer to a maximum of under 4400 years. Here's what needs to be conveyed; I'm open to improving the phrasing. The tests that were done included some that did not overlap (at 1σ confidence) at all. The graph I'm citing from doesn't give me exact values for the error bars, but it's clear that the maximum age of one reading was under 4400 years, and the minimum age on another reading was over 4500 years. The point is that it's tempting to think of 1σ intervals as containing the correct value, but they often don't, and this makes it clear. The original graph shows 26 error bars for the 26 experiments that were done; just glancing at them makes the point quite clear. It's on page 126 of Taylor, Radiocarbon Dating, (1987); his source is Barker (1970), "Critical assessment of radiocarbon dating", Philosophical Transactions of the Royal Society of London A269:23-26. If someone can produce that original article I can recreate the graph and that would probably be the clearest way to explain it. Mike Christie (talk - contribs - library) 18:56, 23 April 2016 (UTC)

I do not understand what was wrong with the IP's edit. It changed "maximum age of under 4400 years" to "maximum age of 4,400 years". The first means maximum of 4,399 years, the revised version maximum of 4,400 years. Similarly with the minimum of 4,500 years. Doesn't the edit just express what you mean more clearly? Dudley Miles (talk) 20:00, 23 April 2016 (UTC)

One of the result bars that sentence refers to extends from around 4250 to 4390 years ago; the other from around 4520 to around 4690 years ago. Those are 1σ confidence intervals. The 4390 and 4520 are approximate figures, because the graph isn't that precise, but it's clear that the maximum is less than 4400 -- it's not 4400. Similarly the other is clearly more than 4500. It looks like more or less like this:

          |------*------|
                      |------*------|
     |------*------|
            |------*------|
                            |------*------|
                                       |------*------|
          |------*------|

.........................X..........X.........................

                      4400       4500

Does that make it clear what's going on? The maximum on the third row is not 4400; it's less than 4400. Mike Christie (talk - contribs - library) 20:19, 23 April 2016 (UTC)

I do not understand confidence levels (apart from a notion that 7 sigma is one in several million and the gold standard - is that right?). I think that the problem is that "The extreme measurements included one with a maximum age of under 4,400 years, and another with a minimum age of more than 4,500 years." sounds tautological. How about "The extreme measurements included one under 4,400 years old, and another over 4,500 years old"? Dudley Miles (talk) 20:46, 23 April 2016 (UTC)

Yes, I can see it sounds odd. I think your suggestion doesn't quite work, because the measurements are ranges, not single ages. The point the sentence is trying to make is that one measurement's result was so recent that even the maximum age of that range was under 4,400 years old, and another measurement's result was so old that even the minimum age of that range was over 4,500 years old. Does that make it clear? I think that phrasing is too clumsy to use, but is it clear what it's saying? Mike Christie (talk - contribs - library) 22:02, 23 April 2016 (UTC)

It was not clear to me (until you explained) that you were talking about ranges. I think you need to spell it out. You could say between 4250 to 4390 years. I am however not clear how conclusive the result is. 1 sigma is only 68%, so there must be a significant probability that the real figure is over 4400. Dudley Miles (talk) 22:40, 23 April 2016 (UTC)

Absolutely; in fact that's the point. Say the real figure is 4,420 years old. Then only two of the ranges I sketched above actually include the real age in the 68% probability range. In the actual example in the source, 6 of the 26 results had ranges that did not include the likely real age. The paragraph in this article says "This obscures the fact that the true age of the object being measured may lie outside the range of dates quoted" and then goes on to describe the experiment we're discussing. Can you think of a better way to say this? I admit I'm having trouble, but then I think it's a complicated point. I think it's worth quoting, though, because it vividly brings home how wrong it is to assume that the true value is in the 1σ range. Mike Christie (talk - contribs - library) 22:48, 23 April 2016 (UTC)

I was just looking at that one sentence in isolation. I will have to look at it properly tomorrow. Dudley Miles (talk) 22:56, 23 April 2016 (UTC)

Suggestions which may (or may not) make things clearer to the non-expert reader. 1. "usually represented by the Greek letter sigma: σ". Change to "usually represented by the Greek letter sigma as 1σ". 2. "This obscures the fact that the true age of the object being measured may lie outside the range of dates quoted". Change to "However, 1σ represents a modest 68% confidence, so the true age of the object being measured may lie outside the range of dates quoted" (I see you mention 68% confidence above. I think either here or above you need to spell out that 1σ is 68% confidence.). 3. Link normal distribution. 4. "The extreme measurements included one with a maximum age of under 4,400 years, and another with a minimum age of more than 4,500 years" Change to "The measurements included one with a range from 4250 to 4390 years ago, and another with a range from 4520 to around 4690." Dudley Miles (talk) 15:14, 24 April 2016 (UTC)

I took your suggestions with a couple of minor changes; how does that look? Mike Christie (talk - contribs - library) 17:40, 24 April 2016 (UTC)

It looks fine to me. Dudley Miles (talk) 17:52, 24 April 2016 (UTC)