Accelerated Radioactive Decay

Oh, yes indeedy-doo. It's one of the main focuses of the RATE group, and the Humphreys study of helium in zircons (on which Syslas is somewhat of an expert, and on which Kevin Henke has written a rebuttal paper that I think is as-yet unpublished) supposedly supports it. From RATE GROUP CONFIRMS FAST DIFFUSION OF HELIUM IN ROCKS:

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Dr. Humphreys reported on the results of laboratory measurements of helium diffusion as a function of temperature in biotites (containing helium from uranium decay in zircons) from two different rocks. The measurements confirm the RATE prediction that diffusion in biotite is rapid. ... The diffusion rate appears to agree closely with a young earth and recent accelerated decay. ... Dr. Snelling presented a preliminary report on the types and locations of radioactive halos in 18 samples from 11 different locations in the United States, Australia, and Europe ... These halos are also physical evidence that a lot of nuclear decay has occurred at some point during the earth's history. ... Dr. Eugene Chaffin presented some advances in his theoretical studies on possible mechanisms for accelerated nuclear decay. He has found a number of connections between nuclear and cosmic constants and accelerated decay. ... Some models appear to have the concept of accelerated decay rates built into them

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That was in 2001, and we haven't heard much more except about helium diffusion, which is discussed in Helium Diffusion Age of 6,000 Years Supports Accelerated Nuclear Decay and from a mainstream viewpoint at Claim CD015.This message has been edited by JonF, 03-16-2005 01:08 PM

I dug up an announcement about RATE at Answers in Genesis:

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A few years ago an initiative was undertaken to research thoroughly the whole area of Radioactivity and the Age of The Earth. The RATE project began as a cooperative venture between the Institute for Creation Research (ICR), the Creation Research Society (CRS) and Answers in Genesis (AiG). ...

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When physicist Dr Russell Humphreys was still at Sandia National Laboratories (he now works full-time for ICR), he and Dr John Baumgardner (still with Los Alamos National Laboratory) were both convinced that they knew the direction in which to look for the definitive answer to the radiometric dating puzzle.

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Others had triedand for some, the search went on for a while in the early RATE daysto find the answer in geological processes. But Drs Humphreys and Baumgardner realized that there were too many independent lines of evidence (the variety of elements used in ‘standard’ radioisotope dating, mature uranium radiohalos, fission track dating and more) that indicated that huge amounts of radioactive decay had actually taken place. It would be hard to imagine that geologic processes could explain all these. Rather, there was likely to be a single, unifying answer that concerned the nuclear decay processes themselves.

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Since, from the eyewitness testimony of God’s Word, the billions of years that such vast amounts of radioactive processes would normally suggest had not taken place, it was clear that the assumption of a constant slow decay process was wrong. There must have been speeded-up decay, perhaps in a huge burst associated with Creation Week and/or a separate burst at the time of the Flood.

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In HELIUM DIFFUSION RATES SUPPORT ACCELERATED NUCLEAR DECAY (PDF document), Humphreys et al write on page 3:

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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.

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Kevin Henke's reaction to this is at "RATE" Leaders Abandon Geologic Fantasies and Admit that Extensive Radioactive Decay has Occurred. His paper has now been posted at Young-Earth Creationist Helium Diffusion "Dates": Misconceptions Based on Bad Assumptions and Questionable Data.{Changed URL of Henke paper and simmediat4ely previous text}This message has been edited by JonF, 03-18-2005 08:00 PM

Where? I see it in .doc format, but mine appears to be the only one in PDF. I don't download .doc files. I got mine from Dr. Henke when he put it out for review.ABE: Never mind, I see it now, at Young-Earth Creationist Helium Diffusion "Dates": Fallacies Based on Bad Assumptions and Questionable Data.This message has been edited by JonF, 03-18-2005 07:57 PM

Yup, and Humphreys et al explicitly recognized that; see the end of Message 11. Of course 99% of creationists won't hear of it from creationist sources, or accept it when it's pointed out.

I am not an expert on the physics of crystallization. It's impossible for any significant amount of lead to be incorporated in the crystal lattice of zircon. Lead inclusions are possible (I think they are rare) but are easily detected (zircon is pretty transparent and lead is not) and are easily avoided (modern SHRIMP systems can measure samples that are disks about 5 μm [0.0002 inch] diameter and 1 μm [0.00004 inch] thick; that's pretty darned tiny).From Zircon: "the Key Mineral":

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Uranium and thorium are found in many minerals, of which, however, only a small number are suitable for dating using the U, Th-Pb approach. This is because only a few are adequately retentive towards them and of these the most retentive is zircon. Other useful minerals include pitchblende (or uraninite, U308), monazite, sphene and apatite. In zircon, the concentrations of U and Th average 1330 and 560 ppm respectively. When in pegmatites, zircons contain more of these elements than they do in normal igneous rocks. Uranium and thorium are found in zircon through the isomorphous replacement of Zr4+ (with an ionic radius of 0.87 ) by U4+ (1.O5 ) and Th4+ (1.10 ) as well as through the presence of thorite inclusions. Such substitution is restricted by the differences in the relevant ionic radii. Pb2+ is excluded altogether because its ionic radius is 1.32 and it bears a lower charge. The result is that zircon does not contain much lead at the time of its formation and has very high ratios for U/Pb and Th/Pb, making it a valuable geochronometer (Bowen, 1988). For this reason, this mineral is widely utilised in dating by the U, Th-Pb isotope method, for instance by C. J. Allgre et al. (1974).

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For pictures of samples, see SHRIMP Analysis - Part 2 and SHRIMP.

The well-known physicist Steve Carlip just posted and excellent summary of how we know that radioactive decay rates are and have been constant (or so close to constant as makes no differnce in the EvC controversy). Age Dating Question:

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The overall result is that no one has found any evidence of changes in fundamental constants, to an accuracy of about a part in 10^11 per year. There are some recent, controversial claims of observational evidence for changes in certain constants (notably the "fine structure constant") in the early Universe, but these are *tiny*, and would have minimal effects on radioactive decay rates.

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So the idea that decay rates could vary enough to make a significant difference to measurements of ages is ruled out experimentally.

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Edited by JonF, : No reason given.