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Author | Topic: Radiometric Dating and the Geologic Column: A Critique | |||||||||||||||||||||||||||||||||||||
Jazzns Member (Idle past 3933 days) Posts: 2657 From: A Better America Joined: |
*nod*
Point taken.
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JonF Member (Idle past 190 days) Posts: 6174 Joined: |
I think it would be more productive to focus on a case for which the paper in question is available on the Internet. But I am pretty sure that nobody, including Woody, has put any such paper (full of cherry-picked discordant dates) on the Internet. Even if somebody did, of necessity much of the detail would be contained in papers not available to non-academics on the Internet. From the last paragraph of STUDIES IN CREATIONISM AND FLOOD GEOLOGY it appears that the contents of "Studies in Flood Geology" (Anti-Climacus' reference)relating to radioisotope dating are nothing more than a reprint of "Radiometric Geochronology Reappraised" (Creation Research Society Quarterly, 16(2)102-29, 147; September 1979) which has been so extensively criticised and debunked in so many venues, including this thread.
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Anti-Climacus Inactive Member |
This thread has officially exploded with responses.
Don't worry though. I am preparing replies. Hopefully in an easier to read format. This, that a man’s eye cannot see by the light by which the majority see could be because he is used to darkness; but it could also be because he is used to a still clearer light, and when this is so, it is no laughing matter.
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JonF Member (Idle past 190 days) Posts: 6174 Joined: |
Reply: But you must look a little closer. How, exactly, did the geochronologist know that there was an open system? For isochrons, it's usually by sophisticated statistical analysis of how well the data fit a straight line. (Since the data does not fit the requirements for the common least-squares analysis to be applicable, much more sophistication is required). In this particular case no sophisticated analysis was required to see that there was no isochron line. Here's the picture again:
Was it by independent examination of samples for weathering or contamination? No. The invocation of contamination and closed system behavior is a purely ad hoc rationalization that can be called upon at any time the data points contradict the expected age of the samples. If there was truly an independent method of weeding out contaminated samples, discordances would not be computed as often as they are There is an independent method; statistical analysis of the fit to a straight line. There's some discussion of this on apge 21 of http://www.bgc.org/Isoplot3betaManual.pdf. Are you seriously proposing that the refusal to draw one straight line through the data points in the figure above is an "ad hoc rationalization"? Or do you agree that those points do not lie on a straight line?
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Loudmouth Inactive Member |
quote: Totally agree. His arguments stand on their own. I use a pseudonym on this very forum so I see nothing wrong with Woody using a synonym in non-peer reviewed publications.
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Harlequin Inactive Member |
Glenn Morton ploted the date from Woodmorappe's CRSQ article and here is the result:
Re: claims that geochronologists are tossing out "bad" dates which results in "consistent" radiometric dates. Those who actually work in the field are very clear that this is not the case. Now why should I not accept the word of thousands of workers involved with radiometric dating? It seems for more likely that a handful of YEC critics are full of it. And as Henke has pointed out the tests are not cheap enough to make the YEC claim viable. I might finally add a good link on the subject: Radiometeric Dating Does Work! by G. Brent Dalrymple. This message has been edited by Harlequin, 12-09-2004 07:41 PM
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NosyNed Member Posts: 9003 From: Canada Joined: |
Didn't someone hint that he referenced his own work without making it clear that it was? That isn't really invalid I suppose but it smells to me.
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edge Member (Idle past 1728 days) Posts: 4696 From: Colorado, USA Joined: |
quote: So, you took erroneous data and then computed averages, max and mins. Great. Just what does that give you? Do you really think you can get anything meaningful? What you are doing is taking the bulk of the data between two arbitrary deviations from the mean and simply throwing it out. And you are the one who says that geochronologists toss out data!
quote: Could you give us a sampling of what those sources are? As far as I know you are making this up.
quote: Most scientist would wonder why you are obsessed with erroneous information. This is an improper way to do statistics.
quote: Just my point. It produces a biased sample. A sample with a bias toward error. The only reason for a biased sample would be that you are selling something, usually something that cannot stand on its own merit. Go ahead and believe this if you want, but I repeat my question about analyzing only the data within one standard deviation of the average. Would you then accept my analysis?
quote: The fact that you stated your sample to be biased admits that your study is completely bogus. I repeat: no one does statistics like this (except, obviously, a wayward YEC).
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crashfrog Member (Idle past 1489 days) Posts: 19762 From: Silver Spring, MD Joined: |
This thread has officially exploded with responses. Maybe I'll bow out. I think others are making the points I wished to; clearer and deeper than I, to boot. Don't feel you have to respond to my posts if you don't wish to.
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crashfrog Member (Idle past 1489 days) Posts: 19762 From: Silver Spring, MD Joined: |
This is brilliant. Exactly what I was hoping someone would be able to do. You can see both the general, if imprecise, corellation preserved in the majority of the "discordinant" dates, as well as the big hole right down the center where the concordinate, valid dates would be.
I notice too that the hole gets wider as the dates get larger; this would be expected as the margin of error increases as the dates rise.
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JonF Member (Idle past 190 days) Posts: 6174 Joined: |
Glenn Morton ploted the date from Woodmorappe's CRSQ article and here is the result: And ... Woody also plotted that data in the same way (or at least a similar set of data) on the top of a left-hand page around the middle of "The Mythology of Modern Dating Methods" (my copy of which is a few thousand miles away right now). He then drew in a blob in the empty area at the lower right and a blob near the "400" on the Y axis and a blob in the empty area at the the top middle of the graph. In these blobs he wrote short derogatory statements about geologists not daring to publish the results that fell inside those blobs. No evidence that any such results existed, no discussion of why he believed such results existed ... just the claims. Ol' Woody. A real piece of work. (edited to add: Yippee! Just went over 1K posts in this thread!) This message has been edited by JonF, 12-09-2004 09:52 PM
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JonF Member (Idle past 190 days) Posts: 6174 Joined: |
Didn't someone hint that he referenced his own work without making it clear that it was? That isn't really invalid I suppose but it smells to me. New Educational Activities for Home Schooling Science: A Hands-on Science Activity that Demonstrates the Atheism and Nihilism of Evolution is the most commonly cited example of such activity. Woodmorappe has in the past threatened to sue people who identified him as Peczkis. Unfortunately for him, Tom McIver outed him in an obscure footnote in a book circa 1988 (probably in Anti-Evolution: An Annotated Bibliography, although I'm not sure) and apparently this made it "public domain" and removed his standing to sue others. I've seen claims that Tom did that and did it obscurely on purpose, for just that reason.
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Dr Cresswell Inactive Member |
quote:I'm not sure of the basis for your claim that "it is clear that many discordant ages are not published". Do you have a whole list of scientists who have said "oh, and we had an additional collection of dates that we didn't like, so they're unpublished"? quote:What I'm proposing isn't an assessment of the accuracy of the measurement of the true age. What I'm proposing is an assessment of the number of unreported discordant results. With measurements using one technique of rocks of a supposed similar age one would expect a smooth bell-like curve (a range in the actual dates would tend to flatten the top); the bit you'd be interested in are the tails of the distribution above and below the main part of the curve. If these follow a smooth decline with decreasing number of results at greater/lesser ages then the chances of discordant results being unreported is low, if there is a sudden step either in the distribution itself or a differential of that distribution then a significant number of discordant results have not been reported. Is that clearer?
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Dr Cresswell Inactive Member |
quote:Yes, you've understood correctly. I've just tried to explain what I proposed a bit more clearly. I was a bit tardy in replying due to other time constraints (I generally rely on the email notification of replies to my post to know if there's been a response ... but that only works if the "reply" button is used). Alan
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Anti-Climacus Inactive Member |
Hello all.
Before addressing your specific objections (which I will hopefully get to this weekend), I would like to provide an example of how geochronology is applied in practice. The radiometric study to be analyzed is related to Rb-Sr Isotopic Systematics of the Lherzolithic Shergottite Lew88516 by Borg et al. The study can be found here. The opening paragraph makes a forceful statement that is typical of geochronological studies, as well as uniformitarians/evolutionists:
quote: Here we see that two different dating methods applied by 4 different studies yielded ages concordant with the expectations of geochronologists. On the surface, this appears to be an outright victory for radiometric dating. We shall soon see, however, that this apparent victory is no such thing, but is instead a superficial camouflage veiling a mountain of rationalizations invoked for the sole purpose of explaining away contradictory data as mere coincidence. The two lines of contradictory evidence in this study are the following: (1) Isochron-yielding leachates producing an age of approximately 726 million years (discordant by about 400%); (2) Four separate mineral separate/leachate pairs yielding an age of approximately 90 million years (discordant by -50%). Borg et al recognize the discordant isochron and plot it in Figure 1. They write:
quote: The geochronologists attempt an explanation for the discordant isochron:
quote: They justify their explanation as follows:
quote: As is clearly seen, the geochronologist is sure to begin his experiment with rationalizations at hand, just in case. They proved to be of great value for this study in particular, because they were used to explain away samples Mask(L), Wr-2(L), Oliv(L), Mg-Px(L), and Fe-Px(L), which formed a very neat isochron that contradicted geochronological expectations. Such a distillation process is invoked frequently by geochronologists to easily discard non-preferable ages. If there is a scatter of unwelcome dates, the typical invocations of alteration, open system behavior, or re-heating events are deployed at a moment’s notice. If the unwelcome dates, however, form an isochron (a very common occurrence, as evidenced by the fact that it took me no more than 5 minutes on-line to find such an incident), then much more imaginative hypothetical geologic events are to be concocted. Hence, the references to secondary alteration and shock metamorphism (p. 1) by Borg et al, which can somehow magically produce analytically precise isochrons with no geologic significance whatsoever. But the dubious nature of such explanations doesn’t end there, as is evidenced by the following statements:
quote: So the very same alteration, open system behavior, re-heating, secondary alteration, shock metamorphism, etc. ad infinitum, that is used to disqualify the validity of discordant data somehow miraculously exempts concordant data from befalling the same fate. This state-of-affairs effectively destroys the concept of open system behavior as a reliability criterion, and instead establishes the concept as a convenient rationalization to be used by geochronologists. Borg et al also recognize the four separate/leachate pairs and plot their slopes in Figure 3. They write:
quote: The geochronologists attempt an explanation for the separate/leachate pairs:
quote: Again, we see how analytical precision of discordant ages requires the concoction of hypothetical geologic processes that allegedly occurred in the distant past. And again, the very reliability criterion — analytical precision — that is used to confirm the validity of concordant data is somehow magically transformed into a fortuitous event when applied to discordant data, for no other reason than the fact that it is discordant. This state-of-affairs effectively destroys the concept of analytical precision (consistency) as a reliability criterion, and instead establishes the concept as yet another convenient rationalization to be used by geochronologists. Another point of notable interest is that Borg et al reference another study where U-Pb isotopic systematics yielded an isochron of 212+-62 (p. 2). This study increases the range of isochrons to over 58 million years (over 32% of the expected age), with the lowest isochron age at 154 and the highest at 212. If we take the wider range that results from taking the max (212+62) and min (154-6), we end up with a range of 126 million years (over 70% of the expected age). This is a generous gap to be claiming agreement between isochrons. But have no fear, just as the geochronologist has a pool of excuses to assist him in narrowing the raw data to his liking, he has a pool of pretexts to justify the implementation of a large net for the designation of agreement between isochrons:
quote: Amazing. When isochrons are developed that exceed analytical uncertainty — even ranging up to 70% of the alleged age to be confirmed — the geochronologist is free to designate contemporaneous intrusions, or simply claim that some isochrons were produced from a slightly different mantle source, which conveniently allows isochrons exhibiting significant age differences to be considered in agreement while safely bypassing the need for analytical precision. In any case, I have seen many of these studies in the past few years, and they have greatly succeeded in not only convincing me of the invalid nature of radiometric dating, but of the fact that the long lists of concordant and consistent radiometric ages are simply the knavish product of completely invalid methodologies designed to confirm an outcome that was pre-determined at the outset. This, that a man’s eye cannot see by the light by which the majority see could be because he is used to darkness; but it could also be because he is used to a still clearer light, and when this is so, it is no laughing matter.
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