Yes, zircons have no significant amount of lead at crystallization because of the basic physics of crystallization. This is acknowledged by those few YECs who understand how it works, the RATE group. In
Helium Diffusion Rates Support Accelerated Nuclear Decay D. Russell Humphreys, Ph.D., Steven A. Austin, Ph.D., John R. Baumgardner, Ph.D., and Andrew A. Snelling, Ph.D. write:
quote:
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 (Humphreys, 2000, 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 worthat today’s ratesof 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.
They realize that the only hope for a young Earth is accelerated radioactive decay, and attempt to make a case for it and fail; see
RATE (Radioactivity and the Age of The Earth): Analysis and Evaluation of Radiometric Dating They admit that this scenarios would have a few problems, such as killing all life twice over by radioactiviy and heat, but they try to minimize it: see
RATE in Review: Unresolved Problems.
Creationists have reported cases in which a known-young sample dated as much older. All of these are frauds. Each and every one.
Cases in which dating methods produce old and very discordant dates do exist, but they are indeed relatively few and most can be explained and have been explained. Creationists just ignore the explanations.
Radiometric Dating: A Christian Perspective is a good introduction and has a section on YEC claims at the end.
An Index to Creationist Claims is a good summary of many claims, a bit dated in some entires.
{ABE} OK, you posted while I was composing.
Edited by JonF, : No reason given.
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