Re: [asa] Polonium Halos

That was sharp using the word lying!!

Are you referring to the Granite Controversy of the late 40s . The book of the title was written by HH Read a devout Christian and an Anglican Lay Reader (preacher). It was a good reed (sic)!

Michael
  ----- Original Message -----
  From: David Campbell
  To: asa@calvin.edu
  Sent: Monday, June 19, 2006 5:55 PM
  Subject: Re: [asa] Polonium Halos

    I know that this has been answered before on this forum, but I didn't save
    it. What is the fallacy in the YEC argument about polonium halos? Someone
    in the Sunday School class that I attend has forwarded an e-mail to the
    class from some YEC organization entitled "Polonium Halos: Unrefuted
    Evidence for Earth's Instant Creation!", and so I would be interested to
    know if there is a simple way to explain what is wrong with the argument
    besides that it comes from a source that is not credible.

  http://www.csun.edu/~vcgeo005/revised8.htm deals with some of the technical geological evidence.

  The basic problem is that Gentry is a physicist with no particular geologic background and so has no competence to support his claim that these are primordial unmodified rocks. Not only (as the article points out) is the occurrence of the halos very localized, in specific geologic settings and not in all granite, but it is in uranium-rich granite that clearly shows, through cross-cutting relationships and mineralogy, that it is younger than other rocks. Gentry would have to endorse an Omphalos-like scenario of God creating the rocks with evidence of history in place, thereby contradicting his claim that they show evidence of no history.

  I saw a bit of video by Gentry supporters claiming that several other features of granite fit with his scenario and are unexplained by conventional geologic ideas. As these features are explained by conventional geologic ideas, those responsible for the claims (I don't know if Gentry himself makes these claims) are either lying about conventional geology or lying about having checked conventional geology. They could claim to have a better explanation (though they need to be honest about their criteria for "better"), but to claim that conventional geology is mystified is untrue.

  Another problem is that, for Gentry's argument to hold, radiometric dating must be valid. He would actually prove that granite formed very quickly very long ago if he were consistent. In order to show that a halo is actually a polonium halo, and to show that polonium should have all decayed before the granite could form conventionally, the laws of radiometric decay must not have changed since the halo formed. In order to show that the halo has anything to do with the formation of the rock, it is necessary to be able to rule out later contamination or modification. If the laws of radiometric decay have not changed, and contamination and alteration can be ruled out, then radiometric dating is valid.
  There's also a problem with the assumption that, in a conventional geologic model, the polonium had to be present in the initial melt and would have all decayed away by the time of crystallization of the granite. Since polonium is continually produced by radioactive decay of longer-lived isotopes, there would be a little Po being formed as long as crystallization occurred. The above article claims that the halo-rich granites were formed through modification of existing rock, rather than crystallizing directly from melt, so the formation time was not overly long. I'm not much of an igneous expert myself, so I can only say that there was a big fight about cooling magma versus replacement origin of granite about 50 years ago or so, and I would not be surprised if it in part reflected some granites being replacement and some being cooled magma.

    --
    Dr. David Campbell
    425 Scientific Collections
    University of Alabama
    "I think of my happy condition, surrounded by acres of clams"

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Received on Mon Jun 19 13:52:09 2006