Buz's refutation of all radiometric dating methods

I don't know about Mull, but Rb-Sr isochrons sometimes give wildly inaccurate results; luckily, such cases are usually easy to detect. It is possible to get a line on an isochron diagram that has no age significance but rather is a consequence of incomplete mixing of isotopically varied sources; see Isochron Dating: Mixing of two sources. This does happen; I don't have a reference off-hand but I know I've seen articles declaring an isochron false because of mixing. It's possible to come up with pathological and in-practice essentially impossible cases in which three sources could mix to form a straight line on an isochron diagram and pass a mixing test, but we can be sure that no noticeable number of such cases have occurred.You can also run into a situation in which an isochron line indicates either the original solidification event or a metamorphic event after solidification or even both; see Isochron Dating: Violation of cogenetic requirement.The most trustworthy radiometric dates are measured by two or more independent methods, and mixing won't give you both a good isochron and a concordant U-Pb date. It's common to use multiple methods (sometimes in different studies): see Radiometric Dating and Consistent Radiometric dates for some examples.FYI, Rb-Sr isn't used much in geochronology anymore, although it's used a lot in isotope geochemistry. The dates, while good within a couple of percent or so, aren't good enough for modern geochronologists. This is partly because the isotopes are a tad more mobile in the solid than we would like (leading to slight open-system behavior)and the slight uncertainty in the decay constant. U-Th-Pb methods are probably the most popular, partly because of the many powerful techniques available in such a complex system of nuclides and partly because the decay rate of U is known far more exactly than any other (bombs and reactors, you know). Ar-Ar probably comes in second, because of its wide applicability.Dr. Ken Ludwig of the Berkeley Geochronolgy Center recently did a survey, which may well be published by now. He sent me some pre-press information, including:"... a few months ago I did a quick literature search of articles presenting new geochronology (excluding rocks of Pleistocene age. for which methods such as radiocarbon, uranium series, optical luminescence.... are important) in a variety of different journals (Geology, Geol. Soc. Amer. Bull., Canadian Jour. Earth Sci., Contrib. Mineralogy & Petrology) for the past 5 years. Of the 164 articles I selected at random, more than 80% were done by either U-Pb (54%) or Ar-Ar/ K-Ar (30%). with less than 5% each were done by Rb-Sr or Sm-Nd. In other words, both Rb-Sr and Sm-Nd are now minor methods in modern geochronology (though they remain extremely important in studies of petrology and crustal evolution)"

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Ar-ar dating is contaminsted from the earth's mantle so as to render it unreliable.

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Your reference is wrong. Snelling is ... er, how shall I put this ...not reliable.He starts with "According to the assumptions foundational to potassium-argon (K-Ar) and argon-argon (Ar-Ar) dating of rocks, there should not be any daughter radiogenic argon (40Ar*) in rocks when they form. When measured, all 40Ar* in a rock is assumed to have been produced by in situ radioactive decay of 40K within the rock since it formed."That's flat-out wrong.K-Ar dating can be in error due the the effects he discusses, but Ar-Ar dating cannot. Ar-Ar absolutely does not assume that there is no 40Ar present when the rock solidifies; it's an isochron method that compensates for initial daughter. Indeed, the rocks from the historic eruption of Vesuvius that were accurately dated using Ar-Ar contained initial daughter. From Just a moment...:"Laser incremental heating of sanidine from the pumice deposited by the Plinian eruption of Vesuvius in 79A.D. yielded a 40Ar/39Ar isochron age of 192594years ago. Close agreement with the Gregorian calendar-based age of 1918years ago demonstrates that the 40Ar/39Ar method can be reliably extended into the temporal range of recorded history. Excess 40Ar is present in the sanidine in concentrations that would cause significant errors if ignored in dating Holocene samples."It is also possible to estimate the amount of initial daughter argon in the K-Ar method, and this is regularly done, in the few K-Ar analyses that are done today. Those who wish to criticise dating methods should criticise concordia-discordia and argon-argon methods, since those are by far the most widely used mthods today.Of course, the fact that so many K-Ar dates agree with other dates indicates that the problem of initial daughter argon is rare.There's some more discussion of Snelling's terrible article near the end of http://members.cox.net/ardipithecus/evol/lies/lie024.html.

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I am not an authority on dating methods and must rely on what I can assimilate from others.

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Unfortunately, you've been assimilating from unreliable sources. Woodmorappe, Snelling, Austin, the ICR, AIG, Plaisted ... they've all been caught telling half-truths and outright lies, attempting to spin-doctor reality.However, reality as mainstream science understands it contradicts your beliefs. I don't know what you want to do about that. Yes, science is tentative and changes ... but we know a lot about the age of the Earth and the life on it, and the evidence is clear; the Earth is old, and life on Earth is almost as old. Honest creationist scientists reached this conclusion long before Darwin and long before radioactivity was discovered.

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I still don't understand how fossils can be dated by dating sediments around them as the materials in the sediments that eventually became sedimentary rocks were so much older than the living organisms fossilized in them.

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Mostly, fossils aren't dated by dating the sediments around them, although that's not universal, and progress is being made on dating sedimentary rock.Yup, if you date the grains of a sedimentary rock, you get a date older than the sedimentary rock (usually the date of solidification of the igneous rock from which the sediment eroded). However, the material that cements the grains together solidifed when the sedimentary rock formed, and there are chemical changes and processes going on during lithification ... and that presents opportunities. And, with ion microprobes and suchlike, we can date incredibly small samples.However, most "radiometric dating of fossils" to date has been performed by dating igneous formations above and below the fossil-bearing sedimentary rock. If you find a 62 million year old lava flow above a fossil and a 64 million year old lava flow below that fossil and no evidence of disturbance of the order of the layers, then the most likely explanation is that the sedimentary rock and the fossil are between 62 and 64 million years old. Do this thousands of times, across the world, cross-correlate the results, and you have a pretty solid and unambiguous body of evidence.

First, note that the vast majority of fossils which have been absolutely dated by radiometric methods have not been dated by dating sedimentary rocks; they've been dated by examining solid, unweathered igneous rocks that happen to lie above and below the fossil. If you wish to argue that our determinations of fossil ages are in error by millions to billions of years, this is the kind of dating you should be examining. As someone else pointed out already, most methods of dating of sedimentary rock is new and experimental, and the few currently solidly useful methods aren't widely applicable.

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But if the organic material is young and the inorganic material it is fossilized in is old, wouldn't the organic young permeate the old grains making up some of the "cement" which solidifies the inorganic. And by the same token, wouldn't the old inorganic permeate the fossil, leaving a false appearance of age on the test for the fossil? I don't see how the test can separate the old from the new when they are more or less fused together. For example, it seems that the fat, blood, water, etc from a young dead dinosaur would permeate into the old sediment particles around it tending to make the whole area, including the bones homogenous in the dating process. And if the dino was only five to six thousand years old, it seems that the sediment dating method wouldn't even factor in such a young thing. Where am I going wrong here?

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It appears that you are going wrong in not having the slightest conception of how the methods might work. No offense meant, the vast majority of people in this world don't have the slightest conception of how the methods might work, and they can be good people and lead happy lives in spite of that.I don't intend to write the book that would be required to get you a real understanding. And the book doesn't exist because the information is so new it's only in the technical literature. And I don't understand it well enough to teach it.But, metaphorically looking at it from 50,000 feet, radiometric dating methods work by measuring amounts and ratios of various elements. The methods work because the amounts and ratios change in certain ways over time before the rock solidifies (or the "cement" lithifies sedimentary rock) and change in other ways over time after the rock solidifies (or the "cement" lithifies sedimentary rock). One major source of the differences is the fact that atoms are more mobile in liquids than they are in solids. The source of the atoms just doesn't matter. It doesn't matter whether the atoms came from dinosaur blood or came in dissolved in the interstitial water or were leached out of the grains that were being lithified; what does matter is that there's different characteristics of the pre-lithification and the post-lithification state.There's a brief Web description of one technique under development: dating grains of xenotime that grow on zircons that are just about to be incorporated into a sedimentary rock. See R&D Development of a Breakthrough Method for Dating Sedimentary Sequences: U-Pb SHRIMP Dating of Diagenetic Xenotime

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How many creationist geologists do you know of that believed this two centuries ago?? How about naming a few.

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In addition to those mentioned already, Hugh Miller. See Hugh Miller -- 19th-century creationist geologist.

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The following link goes into much more detail than could be covered posting each item, about problems which could affect the various radiodating methods. Some of these were hinted at in statements I've made in this thread such as atmospheric changes, etc. If anyone would care to hone in on some of these in rebuttal it might prove to be interesting.

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Well, it does get pretty tiresome refuting the same old silly errors, but what the heck, I'll hit some of them.The article is a collection of misleading half-truths and outright lies."Each system has to be a closed system, that is, nothing can contaminate any of the parents or the daughter products while they are going through their decay processor the dating will be thrown off. Ideally, in order to do this, each specimen tested needs to have been sealed in a jar with thick lead walls for all its previous existence, supposedly millions of years!"Wrong in two ways. First, the system must be sufficiently close to a closed system, not an absolutely closed system. Second, the vast majority of modern dating methods detect when the systenm has not been sufficiently closed, and some (concordia-discordia) can produce a valid date when the system has not been closed."Each system must initially have contained none of its daughter products. A piece of uranium 238 must originally have had no lead or other daughter products in it. If it did, this would give a false date reading"Incorrect for isochron methods, which make up about 40% of the date measurements being done today. True for other methods, but almost always a good assumption for a particular case. For example zircons reject lead so strongly when solidifying that it's essentially physically impossible to get any non-radiogenic lead into a zircon (one of the reasons why U-Pb dating of zircons is the most popular method today)."The process rate must always have been the same. The decay rate must never have changed."True. However, if the decay rate ever had changed that would have physical consequences. The Oklo reactor, supernova 1987a, and may other physical measurements indicate that there were no significant changes in decay rates under natural conditions. The few changes in decay rates that have been obtained in the lab are far too small to change dates significantly, involve elements that are not used in radiometric dating, and involve conditions that are incompatible with the existence of a solid Earth, much less life." One researcher, *John Joly of Trinity College, Dublin, spent years studying pleochroic halos emitted by radioactive substances. "I can't trace this down. I note that Joly lived at the end of the 19th century, around when radioactivity was first discovered, and any of his researches are almost certainly way out of date." If any change occurred in past ages in the blanket of atmosphere surrounding our planet, this would greatly affect the clocks in radioactive minerals"Just plain wrong. It would affect the rate of C-14 production, but would not affect any other radiometric dating in any significant way."The Van Allen radiation belt encircles the globe. It is about 450 miles (724 km) above us and is intensely radioactive. According to *Van Allen, high-altitude tests revealed that it emits 3-4,000 times as much radiation as the cosmic rays that continually bombard the earth.""Any change in the Van Allen belt would powerfully affect the transformation time of radioactive minerals."Again just plain wrong. It would affect C-14 production and nothing else."A basic assumption of all radioactive dating methods is that the clock had to start at the beginning. It is assumed that no daughter products were present; only those elements at the top of the radioactive chain. For example, all the uranium 238 in the world originally had no lead 206 in it, and no lead 206 existed anywhere else. But if either Creationor a major world-wide catastrophe (such as the Flood) occurred, everything would begin thereafter with an "appearance of age.""Yes. If there is a God, and she wanted to trick us into believeing the Earth nd life are old by carefully setting it up so every evidence we look at indicates an old Earth and life, that God could do it. Do you believe in a God that it purposefully trying to trick us?"FIVE RADIOMETRIC DATING INACCURACIESHere are some of the reasons why we cannot rely on radioactive dating of uranium and thorium:(1) Lead could originally have been mixed in with the uranium or thorium. This is very possible, and even likely."Incorrect. In zircons and a few other minerals, it is essentially impossible for any significant amount of lead to be incorporated. Those are the minerals used for U-Pb dating."Leaching is another problem. Part of the uranium and its daughter products could previously have leached out. This would drastically affect the dating of the sample. Lead, in particular, can be leached
out by weak acid solutions."Leaching can happen, although it's easy to select samples in which there has been little leaching. It's not a problem. In isochron methods it's virtually certain that leaching will be detected, and the method will not produce a date. In concordia-discordia methds, it's virtually certain that leaching will be detected and it's very likely that the method will still produce a valid date (otherwise it won't produce a date)."Then there is the problem of inaccurate lead ratio comparisons. Correlations of various kinds of lead (lead 206, 207, etc.) in the specimen is done to improve dating accuracy. But errors can and do occur here also."Yup, they can. And few percent error is possible. You need something that produces much greater errors."Yet a fourth problem concerns that of neutron capture. *Melvin Cooke suggests that the radiogenic lead isotope 207 (normally thought to have been formed only by the decay of uranium 235) could actually have been formed from lead 206, simply by having captured free neutrons from neighboring rock. In the same manner, lead 208 (normally theorized as formed only by thorium 232 decay) could have been formed by the capture of free neutrons from lead 207. Cooke checked out this possibility by extensive investigation and came up with a sizable quantity of data indicating that practically all radiogenic lead in the earth's crust could have been produced in this way, instead of by uranium or thorium decay! This point alone totally invalidates uranium and thorium dating methods."I don't know Cooke's work (did he publish in a real journal?), but neutron capture has been investigated, and the above claims are false."A fifth problem deals with the origin of the rocks containing these radioactive minerals. According to evolutionary theory, the earth was originally molten. But, if true, that would produce a wild variation in clock settings in radioactive materials."This doesn't even make sense.""Why do the radioactive ages of lava beds laid down within a few weeks of each other differ by millions of years?"Glenn R. Morton, "Electromagnetics and the Appearance of Age, " in Creation Research Society Quarterly, March 1982, p. 229."Now, that's amusing. Glenn Morton has examined the evidnece and changed his mind and repudiated all his YEC writings. See http://home.entouch.net/dmd/dmd.htm.

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I'd be willing to bet that he was dating recent lava flows-- within a few hundred or thousand years of the present-- with something like potassium-argon. This trick seems to be very popular.

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That could well be. Certainly Austin does it all the time. Don't forget the xenoliths (older un-melted rocks stuck in the lava); they're just great for generating ridiculously old ages.(Real geologists have no difficulty separating out xenoliths).

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Hmmmmm.........Your statement here seems to be highly supportive of my contention earlier that the flood deposited sediments around fossils are tainted by various old materials deposited near the young to give an old reading.

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Nope. Xenoliths in lava are an entirely different situation, and are easily detected.And you have not yet addressed the facts; the vast majority of fossil dates are not obtained by dating sediments. They are obtained by dating igneous rocks above and below the fossils. Your focus on sediments is a red herring.{edited for spelling}[This message has been edited by JonF, 07-06-2003]

There's a good exposition on Sedgwick in A Flood Geologist Recants.

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I think that Buz is doing a good job of showing us the creationist mentality.

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Yup, a clear case of Morton's Demon.

And the point that many have been trying to make is that you are wrong.C-14 dating requires calibration, and we have that calibration, from several different sources thgat all agree.The vast majority of other radiometric dating methods used today do not rely on any assumptions about chemical make-up or quantity at any time. (Note that K-Ar dating is not widely used today, forming less than 5% of the current analyses, and is essentially always checked by an independent method).One point that I haven't seen made is that the radioactive decays used in radiometric dating occur by wildy different and independent processes (alpha decay, electron capture, beta decay). Nobody has ever succeeded in proposing any possible mechanism that could alter these different processes in just the manner required to make the methods agree as they do.Finally, I love heat .. it's such a problem for creationists. If radioactive decay were accelerated by some process that made a 10,000-ish old Earth appear 4.4 billion years old, the heat released would have fried all life and left today's Earth as a red or even white hot ball of molten rock.