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Author | Topic: Radiometric Dating and the Geologic Column: A Critique | |||||||||||||||||||||||||||
Loudmouth Inactive Member |
I have 2 major problems with Woodmorappes "bad dates".
Critique #1: Woodmorappe is infamous for misusing primary sources. He makes his sources say what he wants them to say instead of what they actually said. One example (found here) shows that Woodmorappe is incapable of honestly portraying the dat from a primary source.
Woodmorappe: "The Pharump diabase from the Precambrian of California yielded an RbSr isochron of no less than 34 b.y., which is not only 7 times the age of the earth but also greater than some uniformitarian estimates of the age of the universe. This superanomaly was explained away by claiming some strange metamorphic effect on the Sr." This would seem to be a problem, trying to throw out a good isochron just because it comes up with a bad date. However, this is far from the truth, as is mentioned by Dalrymple in 1984:
The data do not fall on any straight line and do not, therefore, form an isochron. The original data are from a report by Wasserburg and others [1964], who plotted the data as shown but did not draw a 34billionyear isochron on the diagram. The "isochrons" lines were drawn by Faure and Powell [1972] as "reference isochrons" solely for the purpose of showing the magnitude of the scatter in the data. ... The scatter of the data in Figure 6 shows clearly that the sample has been an open system to Sr87 (and perhaps to other isotopes as well) and that no meaningful RbSr age can be calculated from these data. This conclusion was clearly stated by both Wasserburg and others [1964] and by Faure and Powell [1972]. The interpretation that the data represent a 34billionyear isochron is solely Woodmorappe's [1979] and is patently wrong. Aha, Woodmorappe, by claiming that they threw out an isochron is in fact fudging the data. No isochron ever formed because the data points did not form a straight line. This date was mentioned in the original study because it was an example of the isochron method detecting a contaminated or unclosed system. If such dates are included in Woodmorappe's list of 450 "Bad Dates" then the list contains dates that are known to be wrong for real, testable and logical reasons. How many of Woodmorappe's dates are derived from known contaminated or unclosed systems? We don't know which does not lend credence to those dates. Critique #2: You are claiming that bad dates occur "frequently". What is frequently? 1%, 10%, or 50% of the time? If those 450 dates were pulled from 45,000 total dates, this means that bad dates only occur 1% of the time. I would hardly call that "frequent". So, without knowing the pool from which Woodmorappe pulled his bad dates from you can not make the claim that bad dates occur "frequently" or even at what rate they occur.
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Loudmouth Inactive Member |
quote: Even better, if creationists wanted to save money they could tag along on a geologic survey. They could witness the collection of rocks for dating. They could then travel with those samples to the lab where they are dated. They could ensure that the person doing the dating is blinded from the expected age, much like a double blind clinical trial. The creationist could watch the printers pump out the data and do his own critique of that minutes old data. I can't think of one reason why a geologist would not allow oversight and observation from a creationist organization. It would only cost the creationist organization plane fare and travel costs and spare them the cost of having the samples analyzed. Why don't we see this happening? Because it is easier to fool your audience with smoke and mirrors instead of doing the actual work of substantiating your claims with real evidence. This is why Woodmorappe uses supposed "bad dates", accuses geologists of conspiring to hide the skads of supposed "bad dates", and claims that radiometric dating produces random scatter. He is unwilling to do the work, and probably knows that radiometric dating has none of the flaws he claims it does.
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Loudmouth Inactive Member |
quote: Do you know what is meant by a "bad isochron"? It means that the ratio of the radionuclide and daughter product vary wildly in the same rock sample. A "bad isochron" is produced by movement of the parent and daughter products within the rock sample which indicates an open system. If you are familiar with statistics, a bad isochron will yield a poor r squared value. Bad isochrons are never used to give a date. The example I listed inserted a line representing the expected age to show how badly the scatter was. Dates from bad isochrons are thrown out for objective criteria since a bad isochron is a sign of an open system. Even if a bad isochron gives the expected age it is still thrown out.
quote: Firstly, if we removed radiometric dating there is still more than enough evidence to conclude that the earth is ancient. There is zero evidence that the earth is less than a 100,000 years old, much less 6,000 years. Secondly, there is nothing fallacious about finding metamorphisis in rocks and then applying this to the movement of parent and daughter isotopes in and out of the rocks. Why wouldn't this occur in rocks that have been reheated since their first closure? Why shouldn't geologists look for signs of post-closure modification? Even before an isotopic analysis is done, geologists are able to predict that argon concentration, for instance, has been affected by metamorphisis. Bad dates are not explained away ad hoc, but by observations of how rocks are affected in the present day by the very same forces that happened millions of years ago. First you say . . .
quote: And then you say . . .
quote: So which is it? Is it "impossible to know" or is it "clear"? At what rate do discordances occur? Are they limited to a few geologic features or do they happen with every feature dated? Why didn't Woodmorappe list the number of concordant dates that occured in the very same papers he took the discordant dates from?
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Loudmouth Inactive Member |
quote: Let's use an analogy, shall we? Let's pretend that I take a survey of 10,000 people. I ask them "what time does your watch say"? 9,900 people all give the correct time within 3%. However, 100 people give me an answer that are wildly discordant. Now, I take those 100 people and make a graph showing that watches can vary by almost 100%. I then conclude that watches are not trustworthy and should not be used to tell time. Is that a fair treatment of the data?
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Loudmouth Inactive Member |
quote: I second this suggestion. AC, in your replies to my posts, only focus on how we can determine the frequency of discordance (is it "impossible to know" or "clear" that it occurs frequently). Next, pick what you think is the most damning case of discordance that is well illustrated on the internet. I find it hard not to list examples of well supported concordance, but I can see how that would lead this topic astray. I think we can all wait for you to pick an example and we can work from there.
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Loudmouth Inactive Member |
quote: Willowtree? Anyway, you are right that Woodmorappe is hypocritical in his arguments. He claims that geochronologists are being deceptive by relying exclusively on hand picked results. What does Woodmorappe do? He collects a data set of 450 hand picked results. Is not Woody guilty of the same thing that he is accusing geochronologists of? It would seem so.
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Loudmouth Inactive Member |
quote: That's how I pronounce it. It's a pseudonym, so it really doesn't matter anyway.
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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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Loudmouth Inactive Member |
quote: The rock samples being tested are actually meteors from Mars, literally. They suspected metamorphosis from the shock of the meteor hitting the earth, not a bad assumption given the speed with which meteor can strike the earth. I am definitely not an expert in geologic methodologies, but assuming that shock metamorphisis could have occured is far from an ad hoc hypothesis, or "arbitrary" as AC seems to indicate.
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Loudmouth Inactive Member |
quote: They are out of context because they are taken out of context. It is not our fault that Woodmorappe twists other people work and words to fit his presuppositions.
quote: They DETECT it objectively. The leaching experiments with the martian meteorites is a perfect example. Differences between the samples was detected OUTSIDE OF THE RADIOMETRIC DATING METHODOLOGY. Metamorphosis also results in specific mineral deposits and detectable rearrangements. Metamorphic rocks are not labelled so because they fail to produce concordant dates. They are labelled metamorphic rock because the show outward signs of reheating.
quote: There is not such admission that ALL dating procedures FREQUENTLY produce discordant dates with EVERY sample. Some samples do pose distinct problems due to their history, but this does nothing to dismiss solid dating techniques that are accurate the vast majority of the time. So are discordant dates frequent in EVERY dating assay, or are discordant dates confined to a small number of geologic features? Can you also please define "frequent". Is "frequent" 1%, 10%, 50% or 90% discordant dates? If you don't know, then it wouldn't be innacurate to claim that discordant dates occur 1% of the time, now would it.
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