Talk:Radiometric dating/Archive 2

Archive 1

Archive 2

Sr -- Sm

The list of radiometric dating techniques at the end of the article includes

1. samarium-neodymium (Sr/Nd)
2. samarium-yttrium (Sr/Y)

Both items begin with samarium (Sm), but the chemical symbol shown is that of strontium (Sr) instead of samarium. I'd fix it, but I don't know what was intended. Mike Sarles

Fixed that (one was a duplicate) and removed the following for clarification and/or verification:

• strontium-neodymium-hafnium-lead (Sr-Nd-Hf-Pb)

if it's real it can be put back. Vsmith 18:25, 27 August 2006 (UTC)

These are ratios used in isotope dating of mantle plumes: "Popular with plume enthusiasts is the ratio of helium-3 to helium-4. A higher ratio is characteristic of deep mantle origin, they argue. Similar information can be gleaned from isotopes of the elements neodymium, strontium, lead, and hafnium. The ratio of 3He/4He increases over time as 4He is produced by the decay of uranium and thorium. The present day atmospheric 3He/4He ratio is 1.39x10-6, and is referred to as RA. Geochemists infer deep origins whenever 3He/4He are in excess of 9 to 10 RA. These ratios have been found at hot spot locations such as Hawaii, and are consistently different than the basalts of the mid-ocean ridges....A better interpretation would be that the high 3He/4He ratio arises from a deficiency in 4He in the upper mantle caused by low U+Th areas, and thus low rate of addition of radiogenic 4He." http://www.emporia.edu/earthsci/student/sedlacek2/mantle.htm It's also referred to in the book "Radioactive and Stable Isotope Geology" by Hans-Gunter Attendorn and Robert N.C. Bowen. Valich 00:18, 12 February 2007 (UTC)

"Radiometric" dating?

The section "Short-range dating techniques" in this article contain interesting descriptions concerning various dating methods such as dendrochronology, "varve analysis", "hydration dating" or "obsidian dating", and thermoluminescence.

Strictly speaking, however, those methods do not belong to the topic of Radiometric dating, the current title of this article. Therefore, in my opinion, one of three things should be done: (1) rewrite the section so as not to appear as overtly off-topic; (2) move those other techniques to their proper places and place a link in "See also" section; or (3) rename the article to reflect a more general topic such as "Dating techniques" or the like. What do others think about this? --HYC 21:32, 8 September 2006 (UTC)

Moved three paragraphs to Incremental dating, which was a stub needing more info. Vsmith 22:17, 8 September 2006 (UTC)

Sorry. My fault. I thought U/U, Sr/Nd, Sr-Nd-Pb were radiometric datings but on further research I see they are isotope ratios. Valich 21:15, 10 September 2006 (UTC)

Re: illogical: Supervening influences on half life of samples

I understand that the half-life of a radio-isotope is unaffected by temperature, pressure, etc. But don't other radiological sources have an effect? e.g. the atomic fallout from a meteorite or a supernova in a nearby star system. It seems such events could trigger substantial 'non-spontaneous' decay that would cause is discontinuity in the typical half-life curve and set dates off by an order of magnitude. Also the level of C-14 in the atmosphere could increase significantly in response to such events too: making a sample appear younger than it really is.

No? Are there any reliable sources research on this? Shortopinions 20:00, 29 March 2007 (UTC)

Go to talk/radiocarbon dating, make a "history" and read last week's comments. Jclerman 21:00, 29 March 2007 (UTC)

Same animal dates

Living things have been dated over 2500 years old. so the procedure is not fact. Also different parts of animals have been dated. Example some part is 20000 years old and other is 35000 years in same animal. Posted unsigned, at 06:01, on April 22, 2007 by User:84.249.188.213 (Talk) (5,028 bytes).

Cite the reference and we'll tell you what's wrong. Jclerman 13:43, 22 April 2007 (UTC)

IIRC, that was a creationist lie invented by Kent Hovind. --Robert Stevens (talk) 09:38, 3 January 2008 (UTC)

The procedure is inaccurate either way, since in order to use radiometric dating you have to make an assumption about how many isotopes were in the object being dated, don't you? ex: I'm dating a T-rex, and I find - I don't know - twenty billion isotopes. In order to know how old the rex is based on that data, I'd have to assume that it had a certain number of isotopes from the start. So if the isotopes had a half-life of fifty years, I could assume it started off with 80 billion isotopes and say it's a hundred and fifty years old. Please correct me if I'm wrong. Zillakilla (talk) 01:21, 3 January 2008 (UTC)

Um, yes, you're wrong. Each type of radiometric dating uses the radioactive decay of only one isotope of one element. We know how much of the isotope was present originally by several means: such as measuring the quantity of decay product, in cases where the decay product could not have been originally present (e.g. potassium/argon: argon is a gas, therefore it can't accumulate inside solid crystals except by radioactive decay of potassium-40 in those crystals). --Robert Stevens (talk) 09:38, 3 January 2008 (UTC)

I'm not trying to be obtuse and perhaps this isn't the place for such a discussion, but I don't really understand how, excepting cases like Argon, one could determine how much of the daughter element was present when the decay started. The procedure seems simple enough, but you would sort of need to know that to get an accurate ratio? J. David Sargent (talk) 19:54, 16 March 2008 (UTC)

Discussion of the Problems with Radiometric Dating

I find it curious that there is so little discussion in the article of some of the major problems with radiometric dating. Would anyone mind if I added some information detailing some more of the known problems with radiometric dating?BreshiBaraElohim (talk) 01:44, 18 October 2008 (UTC)

That would be helpful, as long as the information is accurate. I'd be willing to help with a number of methods, especially 14C (which has known problems, such as the variation in atmospheric carbon) and U-Pb (which is generally very accurate). However, I noticed that you've edited several young Earth creationist articles, and several of the problems young Earth creationists use against radiometric dating are suspect and/or taken out of context, so take care with your references. (I'm not saying that it is invalid to hold creationist beliefs, but I would like the science to remain accurate and not propaganda.) Awickert (talk) 02:22, 18 October 2008 (UTC)

Absolutely, that is my intention. I am only seeking to keep the information factual and contextually true. If I post something that is in error, please feel free to re-edit or inform me so I can fix it myself. I appreciate your candid views on the issue. I will not even bother to try and check your history, because I believe it to be irrelevant. The facts should speak for themselves. But yes, I do find some validity in some of the young earth creationist's arguments, and I think it a shame that we are so quick to dismiss them as "religious fanatics" without taking a serious look as any scientific evidence they may have. And it is true that all of the dating systems to date, rely on at least some "expert" interpretation. Often when paleontologists test material, and it does not meet with their presuppositions, they throw out the date as a "bad date". This by itself calls into question their entire methodology. If their presuppositions are ruling their interpretation of the evidence, then that is a problem we should consider, but that is another issue for another time. I am only seeking to provide some factual information as far as some of the known and accepted problems with the radiometric dating system in general. I thank you for your response, and hope you will help me to keep the information accurate and verifiable. BreshiBaraElohim (talk) 04:22, 18 October 2008 (UTC)

OK, perfect, that sounds great. I agree that throwing away data that one doesn't like basically means the method is useless, and is a completely ridiculous and un-scientific procedure - data can only be thrown away with a provable reason as to why the data are bad . . . and often, they show more information rather than less when there are discrepancies! I'm not an expert in dating methods, but I'll keep watching, or you can post on my talk page, for questions! I can also point you to references. I'm glad you're a non-militant creationist :) and I'll be a friendly scientist - and believe me, if the evidence I saw proved a young earth and erased the whole controversy, I'd be happy to see it go. The issue is that the data don't, and so here we are. Awickert (talk) 04:59, 18 October 2008 (UTC)

I am thinking of adding something like this, what do you think?

There are 3 main problems with the methodology of the radiometric dating system. Radiometric dating assumes that: 1. No parent or daughter isotopes were added or removed. 2. That we know for certain the starting point or levels of the parent and daughter isotopes at the origin of the material we are testing. 3. That we know for certain that the rate of decay has been constant throughout the life of the material. [1], [2]

None of these assumptions have been definitively proven, and there is evidence to suggest otherwise. [3], [4], [5], [6], [7]

One of the problems I am having is that there is not a single article on the subject of radiometric dating accuracy which does not clearly show a “young earth creationists” vs. “old earth/universe evolutionists” bias, on either side. As paleontology in general is an interpretive science, it seems it is left to us to interpret the partial and flawed picture of the past that we vaguely have. This creates a lot of conflict on either side, when one side or the other proposes absolute evidence, based on a system the other side finds flawed. It is an interesting dilemma.BreshiBaraElohim (talk) 05:07, 18 October 2008 (UTC)

Yep, those are the assumptions. I can address some of them quickly here, too-quickly and not doing them justice:

1. Yes - this is an important one. Open-system behavior is controlled by reaction kinetics, so most isotopic dating methods used in geology look at the age at which these rocks cool past the point at which they stop replacing the material. For low-temperature materials, like with 14C dating, things that die exit the carbon cycle, so that's well-constrained

2. We know this one pretty well for present-day mantle and melts. Carbon is another story, as that can fluctuate (see carbon calibration curves).

3. There is pretty solid evidence to believe that this is the case. You can check references on the early solar system, and you'll need to think about isotopes that decay very quickly and (if the earth were young) would be adding a ton of heat right now - enough to melt the Earth. So for a young earth, these rates would have to slow, and the other ones would have to change. This would a pretty big assumption!

In your description of the need for a long time constraint to account for the fact the earth is not burning up right now, aren't you making assumptions as to the amounts of parent and daughter isotopes that the earth begun with? If you are using the current level of daughter isotopes, and going back billions of years, and calculating the levels of parent isotopes that would be present, and then using this calculation based on billions of years and transferring those numbers directly to a 6000-10,000 year old earth, of course you would get strange results. Try taking the current level of daughter isotopes, going back 6,000-10,000 years, and calculating the levels of patent isotopes. You will get normal results. See what I mean? There is no way of knowing what levels of parent or daughter isotopes we had to begin with, so any calculations based on assumptions are only as accurate as the original assumptions. Its like this; if I assume that all marbles are red, then I am presented with an assortment of marbles of a variety of colors, then I will be forced to either change my assumption or deny that all of the other colored objects are marbles. My problem with radiometric dating is that they start by assuming all the marbles are red, and leave no room for any other interpretation.BreshiBaraElohim (talk) 07:29, 18 October 2008 (UTC)

For the short-lived oens, we're actually not calculating back billions of years, because there is no measurable parent isotope, as it decays too quickly. In general, scientists measure how much daughter product is in a material that would have started with very little or no daughter product (i.e., iron meteorites don't start with uranium or thorium). For these short-lived isotopes, I think (I'm no expert) that the amount of parent isotope is set by the fact that we observe atoms that form the decay products of these isotopes. Awickert (talk) 18:00, 19 October 2008 (UTC)

One semantic tip is to not talk about paleontologists, but to rather talk about geochronologists. Paleontologists are a standard target for creationists because of the visibility of fossils - but geochronologists are the people who date rocks isotropically - which is more immediately important. Are you familiar with dating methods for crystalline rocks (not sediments)?

I was not aware anyone was under attack. Paleontology is an interpretive science no doubt about it. There are old earth paleontologists and young earth paleontologists, so in my using of the word paleontologist I am assuming it covers both types. Are you assuming that one group are the "real" paleontologists and the other are not?

I was just trying to say that it would sound better if you used "geochronology", and I pointed out paleontology as a point of contention because the vast majority of paleontologists who use geochronology find that it seems that the Earth is old. Awickert (talk) 18:00, 19 October 2008 (UTC)

As far as the crystalline rock dating, are you familiar with radiohalos?[8]BreshiBaraElohim (talk) 07:29, 18 October 2008 (UTC)

I wasn't, but now I am, and I'm unconvinced. VERY tangentially, are you familiar with the fact that it takes on the order of 1 million years for photons to go from the core of the sun to the edge where we can see them? I think that one's really interesting, because a creationist could say that God created the sun in steady-state, but then how do we know that we weren't created just a second ago, in steady-state as well, except for faith? Awickert (talk) 18:00, 19 October 2008 (UTC)

Maybe another thing you could do to bring some of these up is to make an article for Christian Young Earth Creationist Arguments. (Does one already exist?) If the idea is to get as much info as possible out, we would probably reach some sort of an impasse here where we wouldn't be putting out as much info because of argument.

If you are attempting to label all "old earth" theories as science, and all "young earth" theories as something else, then you don't quite understand the dilemma I was referring to earlier. I think there are probably plenty of sites where people who already believe in young earth creation go to feed themselves, just as there are places where people who already believe in an old earth go to feed themselves. I thought Wikipedia was a place where we could reach agreement on some issues. At least the article here should provide factual information. And if the assumptions being made are assumptions, not proven, then it makes sense to label them as such. Just as it makes sense to provide other interpretations of the evidence we do have.BreshiBaraElohim (talk) 07:29, 18 October 2008 (UTC)

I hear where you're coming from, but the problem is that the definition of science is an epistimology based on unbiased investigations. In science, one doesn't go looking for proof for presuppositions. Therefore, the epistimological standpoint states that creation science cannot be pure scientific investigation, in spite of the fact that it uses some scientific methods, because it has already decided on the answer. More specifically here, scientists didn't go looking for an old earth - but they still found lots of evidence for it. Awickert (talk) 18:00, 19 October 2008 (UTC)

I'm going to be super-busy in the upcoming few weeks, and since this seems to be filling up and I actually study things that happen on 100-year time-scales (i.e., rivers), I'm going to sign off. Awickert (talk) 18:00, 19 October 2008 (UTC)

Something you could do is try to dig out landmark papers in geology and read and understand them. I could try to find things too. Unfortunately, I'm going to be super busy, so I might not have much time to do that.

Awickert (talk) 06:15, 18 October 2008 (UTC)

Sure, if you find any articles that you think scientifically support the parent daughter isotope presuppositions, then feel free to link them where I already linked two of such type. In the meantime, do you have any objections to me adding the information I suggested above?BreshiBaraElohim (talk) 10:09, 18 October 2008 (UTC)

I have added some of the information discussed, please feel free to add any aditional links to support the assumptions mentioned. BreshiBaraElohim (talk) 11:29, 18 October 2008 (UTC)

Explaining revert on problems

Awickert has pointed out the basis for the three issues that you describe as assumptions. To state there is no evidence is not true:

I did not state that there is no evidence, I said there is no "definitive proof". BreshiBaraElohim (talk) 11:27, 18 October 2008 (UTC)

1. This is an important assumption which is not always true: geological material can be added or lost. For this reason geochemists and geochronologists have developed ways to determine whether or not such alteration has taken place. There are also methods that can use data where geological material has been lost and still derive a highly accurate age, eg use of the concordia diagram.

2. There is a whole branch of isotope geochemistry and whilst minor improvements continue to be made, the models are robust.

3. This is not so much an assumption as fundamental nuclear physics and backed up by the whole wealth of that science, and I'm not really qualified to explain it. It's a fundamental property of matter. We could as well ask if it has always been the case that salt dissolves in water, or that gravity has always operated the same way. There is no scientific evidence to suggest any of these processes has changed over time. It would be a new discovery to suggest that any of them had changed and that would need evidence. Scientific endeavour works on the assumption that the processes we observe today worked the same way in the past - unless someone can provide evidence to the contrary. This is uniformitarianism. We cannot study any historical science (geology, archaeology etc) without making that assumption. Obviously if you have read evidence that nuclear decay (and thus decay rates and constants) varied in the past that would be fascinating. The claims published online [9] based on Genrty's work have been refuted [10] [11].

I'm not sure what you mean by "definitively proven" - by what standard do you mean? Nor do I follow the relevance of "paleontology in general is an interpretive science"? I mean, the issues you raise are unconnected with palaeolontology, which works from a different set of principles than radiometric dating, let alone evolution, which is part of a completely different science.

Hmm, now you recognize I said "definitively proven" rather than, "no evidence" as you misstated above. If you are unfamiliar with the term "definitive," or "proof," I suggest you consult a dictionary rather than wildly blanking out my edit.

It is unreasonable to expect "definitive proof" in the scientific sense. Nobody proves anything except mathematicians.

I have followed through your links: The link from detecting design [12] is fairly inaccurate, confuse isochrons and errorchrons and concordia. And the exclusing "except for the isochron methods" is hugely confusing - read the articles on different methods here and you will see almost all are isochron methods. And the link actually supports radiometric dating and its underlying assumptions! Read the conclusion[13]. Did you actually read through it completely? I commend that article to you. Babakathy (talk) 11:15, 18 October 2008 (UTC)

I listed quite a few links. If you have a problem with one of them, why not discuss its removal, instead of blanking out the entire edit?

I have been discussing making this change all day here, and the only person who joined the discussion seemed to lose interest, so I tried posting the edit. There is no need to blank out the entire edit. Let's discuss this like rational people.BreshiBaraElohim (talk) 11:27, 18 October 2008 (UTC)

Please don't take the lack of others in this discussion as implying agreement with you. Most people who seek to undermine radiometric dating do so in pursuit of a creationist agenda, and most people with a scientific training and limited time know from bitter experience that trying to discuss anything that contradicts Genesis with a creationist is like trying to teach a rhinoceros to tap-dance. I saw your original edit, followed your links to various creationist websites, and drew my own (erroneous?) conclusions. Your edit was removed before I got around to responding. Pterre (talk) 14:48, 18 October 2008 (UTC)

I reverted the edit because it was inaccurate. What you describe as assumptions are either (2) and (3) widely accepted and backed by all available evidence - the links you cite have been refuted or simply restate your claims. I have explained why citing (1) as a problem is erroneous. And of course one of your links refutes your claims anyway. The issue on evidence vs proof is about how physical sciences work - with evidence: geology cannot be proven like mathematics - instead we observe what the evidence tells us. Babakathy (talk) 11:34, 18 October 2008 (UTC)

This [14] is an excellent resource if you want to read more about the topic. [15] and for mantle chemistry issues (2) [16] [17] Babakathy (talk) 11:38, 18

October 2008 (UTC)

I am sure you are familiar with the logical fallacy of an appeal to popularity. Therefore, "widely accepted" is not proof in itself. And, you claim your theory is backed by all available evidence, but this is another example of a problem with the entire approach. Your "all available evidence" is all of the evidence left after all of the "bad evidence" that does not support the presupposition has been thrown out.

I did not post anything that was not true or erroneous, so to claim so is erroneous. I posted that A. the assumptions that radiometric dating assumes have not been "definitively proven", and B. there is evidence that these assumptions are wrong. If you don't like the evidence, that is more of an issue of your presuppositions that are in danger of being shattered. If the evidence has been refuted as you believe, why not add a statement to that effect with a link. Again, there is no need to wildly blank the whole edit.BreshiBaraElohim (talk) 11:47, 18 October 2008 (UTC)

As I explained above, your "assumption" (2) is neither always assumed, nor a problem for the method. On (2) I have given you links to sites which explain how this issue is studied and that it is not a problem. On (3) I have given you links which refute Gentry's claims. Furthermore, it is not appealing to popularity to say that this is fundamental physics. You should not expect me to provide detailed references for something so fundamental. Nevertheless, some of the links - including 'your link [18] do actually explain this. In sum: your edit claimed that radiometric dating is based on assumptions that are not definitely proven. This is not the case, thus the revert. I am going offline as I have other things to do but do not take this to mean "lack of interest". Babakathy (talk) 12:03, 18 October 2008 (UTC)

Look, the entire article is practically a shrine to the validity of the method, I think one small mention of some of the other interpretations of the evidence and some of the possible problems with it, is consistent with the spirit of Wikipedia. If you think an appeal to popularity is the answer, then you will win, because you are right, your position is more popular; I won't deny that. However, Have you given any serious thought to the problems with your approach using a predeclared outcome to determine if the results of the testing are "good" or not?BreshiBaraElohim (talk) 12:13, 18 October 2008 (UTC)

I removed the link you didn't like, feel free to add information of your own if you would like.BreshiBaraElohim (talk) 11:57, 18 October 2008 (UTC)

Assumption 1. This is already mentioned in the first paragraph of limitations, but I have added some text. It is only a problem if you do not check for alteration and contamination and not a problem at all for some methods. I have provided references.

Assumption 2. I have worked a sentence on this into the text. As I said before, mantle chemistry is well known and well-modelled by now. I have provided references.

Assumption 3. The constancy of radioactive decay is not an assumption, but is supported by evidence. Your own link says so 3. The half-lives of radioisotopes can be predicted from first principles through quantum mechanics.

Emery, G. T., 1972. Perturbation of nuclear decay rates. Annual Review Nuclear Science 22: 165-202

Shlyakhter, A. I., 1976. Direct test of the constancy of fundamental nuclear constants. Nature 264: 340

It is not an assumption and so it is misleading to put this claim on the article.

Your links:

[19] is about radiohalos and has been refuted extensively [20] [21] - as discussed on Radiohalo.

[22] claims that decay constants are not constant, invalidating radiometric dating. This is false: any differences are very small and your own link [23] says so. See comments above on assumption 3.

[24] are about whether or not distance from the Sun influences decay . The article speculates about what could be involved but the only facts relate to solar distance.

[25] Wiens refutes your claims and others - he does not support your argument

Differences in decay rate refered to in [26] are very small differences that will not affect age calculations. Babakathy (talk) 13:10, 18 October 2008 (UTC)

Wow, what you call "adding a few words" looks a lot like a blanking out another's entire factual edit, and an attempt to hide all of the scientific facts that don't support your interpretation of the data.BreshiBaraElohim (talk) 09:07, 19 October 2008 (UTC)

Do you actually read what you reply to? The 3 issues you raise are discussed and proper references provided: (1) see first paragraph of preconditions (2) Last paragraph of the age equation (3) third paragraph of radioactive decay. Please read the article! Babakathy (talk) 10:52, 19 October 2008 (UTC)

Age Equation and Restructure

I substitued the age equation from the USGS site with the more complete one. I was concerned that the current equation gives the impression you can calculate the age of a single measurement on a sample without information on original compositions. Of course, you never should calculate the age of a single measurement on a sample, you should use isochrons or concordia, which is of course what is done, but the equation I have put in is more complete.

I have also reorganised the first section as almost everything we were discussing in the two debates above was already there.Babakathy (talk) 17:37, 18 October 2008 (UTC)

Preconditions

I reverted this edit as (a) it is essentially vandalism to write in such a sarcastic tone and say ignore but add the links and (b) the issue of radiohalos has been discussed in the text page above this section and on the radiohalos article. Several authors have provided numerous links explaining why radiohalos do not show what you think they do. Read them before you put this text back. Babakathy (talk) 10:47, 19 October 2008 (UTC)

Good on ya, we wouldn't want those nasty radiohalos to interfere with our presuppositions.BreshiBaraElohim (talk) 12:07, 19 October 2008 (UTC)