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Junior Member (Idle past 5053 days) Posts: 18 From: Los Angeles,California,USA Joined: |
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Author | Topic: Radioactive carbon dating | |||||||||||||||||||||||
JonF Member (Idle past 195 days) Posts: 6174 Joined: |
Fossils are not dated using carbon dating. Carbon dating is applicable only to organic remains, which describes very very few fossils, and applicable only to things less than 40,000 to 50,000 years old, which again describes very few fossils. (Older things will still have a little radioactive carbon in them, but the amount does not indicate the age). There's a very good description of the carbon dating method, by a creationist, at How does the radiocarbon dating method work?. Carbon dating is tremendously well validated by comparison with other methods, some involving other radioactive methods and some not involving radioactivity. THer's a nice discussion at Lake Varves.
Fossils are dated by using other radioactive methods. The most commonly used methods are U-Pb concordia-discordia methods, followed by Ar-Ar methods, followed by various isochron methods. Usually the fossils themselves cannot be dated, and usually the rocks (typically sedimentary) in which the fossils are encased cannot be dated. Mostly we date igneous or metamorphic rock above and/or below the fossil-bearing formation. Luckily there are lots of such circumstances, enough to put together a pretty comprehensive and cross-checked picture. There's a very good explanation of how radiometric dating methods weork at Radiometric Dating: A Christian Perspective. But you seem to be asking why we think that the decay rate of radioactive material is constant. There are many reasons, both theoretical and experimental. See Re: summing up, & one more question for a brief list of the major lines of evidence. See Claim CF210 for a more detailed discussion with several references. Sorry, Ned, I can't see how to restrict this to just carbon dating and still address his major question.
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JonF Member (Idle past 195 days) Posts: 6174 Joined: |
Do not weather climates and such things matter? No, they do not matter. There's been lots of investigation and experiments. As Bill Murray said:
quote: This message has been edited by JonF, 05-07-2006 04:51 PM
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JonF Member (Idle past 195 days) Posts: 6174 Joined: |
Have you read much of the research carried out by the RATE Project, in particular the investigation into C14 in diamonds? Yes. They are either ignorant or deliberately misleading, and I think it's unlikely that they are ignorant. 14C is produced by high-energy particles ineracting with 14N. Most of it is produced in the upper atmosphere; the high-energy particles are cosmic rays. But it's also known that decay of uranium produces some appropriate particles. So, wherever there is 14N (and we know there's 14N in diamond) and uranium (which might well have been near or in the diamonds; we don't know for sure, but it's quite possible) there is going to be a little 14C. Their claim that diamonds cannot be contaminated with modern carbon (" ...a diamond has remarkably powerful lattice bonds, so there is no way that subsequent biological contamination can be expected to find its way into the interior.") is not supported or reasonable; natural diamonds have flaws and cracks into which groundwater can intrude, no matter how powerful the atomic bonds. The RATE group made no rational scientific estimate of how much 14C should be present in diamonds. I doubt that we have enough data on their history to do so, but I could be wrong. But the RATE guys assumed, without explicitly stating so, that the only source of 14C is the atmosphere; and we know that's not true. So their "study" is worthless, being based on an obviously faulty assumption that they didn't state.
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JonF Member (Idle past 195 days) Posts: 6174 Joined: |
example is K-Ar ”dating’ of five historical andesite lava flows from Mount Nguaruhoe in New Zealand. Although one lava flow occurred in 1949, three in 1954, and one in 1975, the ”dates’ range from less than 0.27 to 3.5 Ma. Well no shit. The lower range of today's K-Ar technology is around 200,000 years, some of the very best systems may read down to 100,000 years. The people at AIG know that. Read the age of something that is 100,000 years old and you will get a reading of about 100,000 years using today's very best methods and equipment. Test something that is 10,000 years old and you will get a reading of 100,000 years. Test something that is 1,000 years old and you will get a reading of 100,000 years. Test something that is 100 years old and you will get a reading of 100,000 years. They knew that before they did the tests. They were not looking for truth but rather the answer they wanted. But this case is an even greater example of them lying. One thing that happens during volcanic activity is that there are inclusions, pieces of older material broken off and carried in the magma. Again, if they are scientists or even educated laypersons, they know that. Those inclusions will test older than the surrounding magma because, guess what???? They ARE older. But AIG does NOT post those facts on their website because their goal is to con Biblical Creationists and they know that Biblical Creationists are so ignorant that they will not spot the flim-flam. Xenoliths (older inclusions) aren't omnipresent and don't always pose a potential problem, but they are omnipresent in Nguaruhoe lava (as acknowledged by Snelling, the author of the "study"). He specifically asked for a "whole rock" analysis, meaning all the constituents ground up together and then tested, which was guaranteed to produce an age older than the eruption of the lava. From ANDESITE FLOWS AT MT NGAURUHOE, NEW ZEALAND, AND THE IMPLICATIONS FOR POTASSIUM-ARGON "DATING":
quote: Most if not all creationist "studies" of radiometric dating are frauds. This particular one is the most blatant fraud of all of them Edited by JonF, : Fixed tag
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JonF Member (Idle past 195 days) Posts: 6174 Joined: |
xplain to me how it's been proven wrong.. You know, you're starting to sound like you're making this up as you go along.
It's off topic here, and there's far too much information to cover adequately here, but History of the Collapse of "Flood Geology" and a Young Earth is a good place to start.
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JonF Member (Idle past 195 days) Posts: 6174 Joined: |
but it does seem to imply that any given magma containing potassium-argon was hot enough to produce short half-life k40 isotopes which are hard to distinguish from full half life k40 isotope elements They must be really hard to distinguish; they've never been detected, even in experiments measuring half lives. Of course, if there were such a thing, K-Ar dates and Ar-Ar dates would often disagree with other dating methods. Such disagreement is rare and usually explainable by other phenomena, therefore short half life isotopes probably do not exist and, if they do exist, are rare enough to be insignificant. Examples of methods agreeing: Are Radioactive Dating Methods Consistent With Each Other?, Consistent Radiometric dates, Radiometeric Dating Does Work!, Radiometric Ages of Some Early Archean and Related Rocks of the North Atlantic Craton (PDF document).
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JonF Member (Idle past 195 days) Posts: 6174 Joined: |
I would be suprised if Ar40/Ar39 isn't the preferred method of choice.
Actually, U-Th-Pb dating, mostly U-Pb in zircons, is used in over half the geologic dating studies. K-Ar and Ar-Ar combined are around 30%. YECs don't like to address U-Th-Pb dating 'cause it's so robust. K-Ar has the potential of error, especialy when purposefuly misappied by YECs, but it's well-understood and low cost, so it's still useful.
Think volcanic surface and the impossiblity of old rock being on it. OK, I'm thinking. Let's see; lava often contains xenoliths, so it is not impossible to have old rock on and in recent lava; in fact it's fairlyh common. Satisfied?
Dr.Henke thinks Steve Austin somehow included old rock in his dating by accident. If you are referring to Young-Earth Creationist 'Dating' of a Mt. St. Helens Dacite: The Failure of Austin and Swenson to Recognize Obviously Ancient Minerals, then he did mention xenoliths as one of segveral possibilities for the anomolous dates.
Somehow, I doubt it. Obviously. Do you have any rational reasons for your doubt, or is it just because of your preconceptions? Note that we actually have data that indicates that dating of recent lava flows is often accurate: Ar-Ar Dating Assumes There Is No Excess Argon?. YECs need not one erroneous date, not a hundred erroneous dates, not ten thousand erroneus dates; they need 100%, hundreds of thousands if not millions, of erroneous dates every single one of them. A few anomolies are irrelevant in this context.
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JonF Member (Idle past 195 days) Posts: 6174 Joined: |
Ar-Ar is also very robust. My former colleagues used this for crater dating studies; they ONLY used Ar-Ar dates, not K-Ar, because Ar-Ar can give narrow and reliable error bars (much better than K-Ar). I've never seen the YEC's address this method, either.
Yup. Wher applicable, U-Th-Pb gives even smaller error bars, partly because the decay rates are known more exactly than for any other systems (bombs 'n breeders, you know). Woodmorappe gave a couple of feeble swats at concordia-discordia dating in Mythology of Modern Dating Methods, but they were even feebler than the rest of the book, and that's pretty bad.
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JonF Member (Idle past 195 days) Posts: 6174 Joined: |
I notice you've dropped any pretense of having defndable claims.
No, I don't agree with the assumption the xenoliths are old They're older than the lava flow. And their age is not an assumption. It's a measurement.
I have rational ones; I assume you have yours unlike your other paranoid opponents. Are yours secret?
I checked out the article and wasn't very impressed. Why not? I find it impressive that 70% of recent lavas give accurate K-Ar dates and the remaining 30% have small errors. What's unimpressive?
Granted you guys got really lucky with neo-Roman city of pompeii, but given it's stone structures, I would say it isn't as old as the argon-argon date. Boy, are you confused. The date is for the lava that covered Pompeii, not the city's structures.
so I have to give you credit for defendy the crappy method of Potassium-Argon dating decently. Alas, I can't give you or the YECs any credit for attacking any kind of radiometric dating; they're frauds, and you are at least awesomely ignorant of the field and have no basis for any evaluation.
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JonF Member (Idle past 195 days) Posts: 6174 Joined: |
Radioactive carbon dating and its accuracy is not based on any claim on constancy of solar flare activity.
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JonF Member (Idle past 195 days) Posts: 6174 Joined: |
Carbon dating was the first and only method of dating for 10 years. Way off. Rutherford dated the first rock in 1905, and the field was developed continuously from then. Libby invented carbon dating in 1949.
You cannot date any fossil properly without knowing how much of the parent substance there was to begin with. Any fossil rich in the parent substance (be it argon, or potassium, etc.) would give inaccurate data. You can't know how much time has passed if you don't know how much sand was in the hourglass to begin with. This is pretty basic. Sorry, wrong. In fact, many methods produce the amount of the parent substance that was initially present as a side effect of the method. E.g. isochron methods and the Ar-Ar method. By far the most widely used method, U-Pb, takes advantage of the fact that significant amounts of lead physically and electrically can't get into minerals such as zircons at solidification; the atoms just don't fit. The only significant source of lead in zircons is radioactive decay. This is acknowledged by the few YECs who have some knowledge of the facts:
Humphreys, Baumgardner, Snelling and Austin writes: Samples 1 through 3 had helium retentions of 58, 27, and 17 percent. The fact that these percentages are high confirms that a large amount of nuclear decay did indeed occur in the zircons. Other evidence strongly supports much nuclear decay having occurred in the past [14, pp. 335-337]. We emphasize this point because many creationists have assumed that "old" radioisotopic ages are merely an artifact of analysis, not really indicating the occurrence of large amounts of nuclear decay. But according to the measured amount of lead physically present in the zircons, approximately 1.5 billion years worth at today’s rates of nuclear decay occurred. Supporting that, sample 1 still retains 58% of all the alpha particles (the helium) that would have been emitted during this decay of uranium and thorium to lead. {emphasis in original} We all would appreciate it if you would learn something about the subject before making claims about it. HTH. TIA.
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JonF Member (Idle past 195 days) Posts: 6174 Joined: |
When Zircons (or other gems, such as monazite) form, they exclude lead, but can have considerable levels of Uranium. As the Uranium decays, lead is produced. Sounds logical. Except you still do not know the levels of Uranium to begin with.
And the initial level of uranium is not part of the equation. I.e., it's irrelevant. Pb-Pb and U-Pb isochrons aren't used all that often. The majority of all dates performed in the last decade or so, and probably before that, are concordia-discordia dates. Address the consilience between different dating methods, proving their reliability, at Age Correlations and An Old Earth (ver 2 no 1).
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