Posted by: paulgarner | June 1, 2009

Are polonium radiohalos primordial?

Polonium-218 radiohalo. Photo by Mark Armitage. From:

Polonium-218 radiohalo. Photo by Mark Armitage. From:

A few weeks ago I wrote about the revolution in thinking concerning granite formation which has taken place in the last couple of decades. In that post, I alluded to Andrew Snelling’s work on polonium (Po) radiohalos, the formation of which seems to impose severe constraints on the cooling history of granite bodies.

It soon became evident that there’s a lot of confusion among creationists and others about Snelling’s model for the origin of these radiohalos and how it compares with the original model proposed by another creationist, Robert Gentry. Although Gentry’s pioneering work did so much to bring radiohalos to popular attention, it is important that we realise that his model for their formation is not the same as Snelling’s.

Basically, Gentry proposed that the Po isotopes (which decayed to generate the halos) were instantaneously formed by divine fiat during Creation Week and that the rocks bearing them were thus primordial, created rocks. However, as Snelling and others have shown, this hypothesis is inconsistent with the abundant evidence (from field relationships and petrological data) that Po radiohalo-bearing granites were formed by the crystallization and cooling of magmas. Often the host rocks into which such granites have been intruded (and which are therefore older than the granites themselves) originated as fossil-bearing sediments thought by most creationists to have formed during the global Flood.

Snelling’s model, by contrast, is a hydrothermal fluid transport model, in which the Po isotopes were produced by U-238 decay in zircon crystals found in the same biotite mica flakes as the Po radiohalos (Snelling 2005). The hydrothermal fluids released by the crystallizing and cooling granite magma flowed along the biotite cleavage planes and transported the Po isotopes from the U-238 radiocentres. The Po isotopes were then precipitated in lattice defects along the same biotite cleavage planes where sulphur, chlorine and other atoms chemically attractive to Po were located, within a millimetre or so of the U-238 radiocentres. These Po precipitation sites became the radiocentres for the Po halos.

As the Po in the radiocentres decayed, new Po atoms were supplied from the hydrothermal fluids flowing through the mica. Thus, provided the supply of Po isotopes was sufficient and the hydrothermal fluid flows were sustained and rapid, the required Po concentrations would have been supplied to the radiocentres to generate the Po radiohalos within hours or days, consistent with the fleeting half-lives of the Po isotopes.

A constraining factor on the preservation of the Po radiohalos is that the alpha-particle damage left by the Po decay is retained in the mica flakes only below 150 degrees C. Above this annealing temperature, the damage either doesn’t register or is obliterated. Thus, all the radiohalos in the granites had to form below 150 degrees C, which is relatively late in the cooling history of granite. (Granite magmas when intruded are at temperatures of 650-750 degrees C, and the hydrothermal fluids are released at temperatures of 370-410 degrees C after most of the granite and its constituent minerals have crystallized).

Snelling and Gates (2009 p.68) write:

“However, the accessory zircon grains with their contained 238U crystallize very early at higher temperatures, and may have even been already formed in the magma when it was intruded. Thus the 238U decay producing Po isotopes had already begun well before the granite had fully crystallized, before the hydrothermal fluids had begun flowing, and before the crystallized granite had cooled to 150ºC. Furthermore, by the time the temperature of the granite and the hydrothermal fluids had cooled to 150ºC, the heat energy driving the hydrothermal fluid convection would have begun to wane and the vigor of the hydrothermal flow would also have begun to diminish … The obvious conclusion has to be that if the processes of magma intrusion, crystallization, and cooling required 100,000–1 million years, then so much Po would have already decayed and thus been lost from the hydrothermal fluids by the time the granite and fluids had cooled to 150ºC that there simply would not have been enough Po isotopes left to generate the Po radiohalos …”

Thus, taking all these factors into account, Snelling has concluded that the granite intrusion, crystallization, and cooling processes must have occurred together over a timescale of only about 6-10 days. This is helpfully summarized in Figure 8 of Snelling (2008), reproduced here.

Schematic, conceptual, temperature versus time cooling curve diagram to show the timescale for granite crystallization and cooling, hydrothermal fluid transport, and the formation of polonium radiohalos. Figure 8 from Snelling (2008).

Schematic, conceptual, temperature versus time cooling curve diagram to show the timescale for granite crystallization and cooling, hydrothermal fluid transport and the formation of polonium radiohalos. Figure 8 from Snelling (2008).

So to summarize:

According to Gentry, granites are primordial rocks, formed by divine fiat during the Creation Week, and the radiohalos they contain were generated by primordial polonium created in situ.

According to Snelling, granites were formed by the crystallization and cooling of magmas, including during the global Flood, and the radiohalos they contain were generated by polonium separated by hydrothermal fluids from nearby uranium sources.

Only Snelling’s model is consistent with the variety of geological settings in which the Po halo-bearing rocks are found.


Snelling A. A. 2005. Radiohalos in granites: evidence for accelerated nuclear decay. In: Vardiman L., Snelling A. A. and Chaffin E. F. (editors). Radioisotopes and the Age of the Earth: Results of a Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California and Creation Research Society, Chino Valley, Arizona, pp.101-207.

Snelling A. A. 2008. Catastrophic granite formation: rapid melting of source rocks, and rapid magma intrusion and cooling. Answers Research Journal 1:11-25.

Snelling A. A. and Gates D. 2009. Implications of polonium radiohalos in nested plutons of the Tuolumne Intrusive Suite, Yosemite, California. Answers Research Journal 2:53-77.

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  1. Unfortunately it is by no means proven that these ring-shaped discoloration haloes in primordial granite rocks are actually due to Polonium-218 … Radon-222 is a more likely candidate.

    Lots of info here:

    • The suggestion by Brawley that the polonium-218 radiohalos are, in fact, misidentified radon-222 radiohalos does not stand up to critical examination.

      Brawley acknowledges that it takes 500 million to 1 billion alpha emissions to produce each visible ‘ring’ in a radiohalo. He also acknowledges that radon-222 is an inert gas. But therein lies the fatal flaw in his hypothesis. Since radon is chemically inert, there is no reason why it should concentrate into radiocentres and reside there long enough for all 500 million to 1 billion alpha emissions to occur.

      Of course, in Snelling’s hydrothermal fluid transport model, radon is part of the migration process that separates the polonium, and we see evidence of that in the radiation staining along the cracks through which the transport took place. But such staining just goes to show that the radon wasn’t concentrating into radiocentres.

      Polonium, by contrast, exhibits similar chemical behaviour to lead and so is particularly attracted to atoms such as the halides and sulphur. That’s why it’s not until the radon decays to polonium that the polonium has the chemical attraction to be concentrated in discrete radiocentres, and then goes on to produce the polonium radiohalos.

      In other words, the available evidence strongly suggests that the radiohalos have been correctly identified. I note in passing that Brawley’s article was written in 1992 and that it precedes all the data collected and published by Snelling and co-workers on this subject, e.g. the selection listed here.

  2. You dismiss Brawley’s argument (which I do not !), which means you still have to refute the arguments raised by professional geologist Tom Bailleul:
    This site was last updated in 2005, if you care about how recent these pieces have been written.

    My main point is that it is not at all proven that Polonium-218 *is* the cause of the radiohaloes. You present this as a given, whereas I point out that this is a theory, or even a hypothesis.

    • I’m pleased that you’ve retreated somewhat from your original claim that radon is “a more likely candidate” for the origin of these radiohalos, to the less definite claim that a polonium origin is not proven. Of course, science doesn’t deal with proof, but evidence, and the evidence strongly supports a polonium origin.

      In my first response I addressed Brawley’s web article because that was the one most relevant to Snelling’s hypothesis. However, let’s take a brief look at Baillieul’s article, in which he makes four main points. Here they are with my responses:

      1) Ballieul: Gentry’s samples do not represent primordial basement rocks. Response: Agreed. But that was the main point in my original post: Gentry’s hypothesis for the origin of the radiohalos is not the same as Snelling’s, and only Snelling’s fits with the variety of geological settings in which the halos are found.

      2) Ballieul: The halos are not the product of alpha decay damage. Response: Snelling (2000 pp.383-390) has reviewed the compelling evidence from many years of published investigations that the radiohalos are the product of alpha decay damage. Most importantly, the radii of the concentric spheres have been shown to correspond to the ranges in the host minerals of the alpha-particles from the alpha-emitting isotopes in the uranium-238 and thorium-232 decay series. If Ballieul thinks he has data to the contrary, he should submit it to peer-reviewed journals.

      3) Ballieul: The halos may be caused by radon, not polonium. Response: This is a restatement of Brawley’s hypothesis, which is not consistent with the fact that radon is chemically inert and cannot therefore concentrate into radiocentres for long enough to form mature halos. (Incidentally, I didn’t “dismiss” Brawley’s argument in my first response, I pointed to evidence suggesting that it is mistaken.)

      4) Ballieul: There’s lots of other evidence pointing to a great age for the earth. Response: Perhaps, and I’m happy to discuss such matters in other posts. However, I’d like to keep the discussion focused here on the polonium radiohalos.


      Snelling A. A. 2000. Radiohalos. In: Vardiman L., Snelling A. A. and Chaffin E. F. (editors). Radioisotopes and the Age of the Earth: A Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California and Creation Research Society, St. Joseph, Missouri, pp.381-468.

  3. I don’t think I retreated: I said *twice* that it is by no means proven that Polonium-218 causes the radio haloes. I also said in my first reaction that Radon-222 is the more likely candidate, which I did not repeat a second time. I still think that is the case, if you like me to repeat that.

    The main point is that it is not at all proven that Polonium-218 *is* the cause of the radiohaloes (irrespective of what would then be the cause). You pretend that the case for Polonium-218 is conclusive, whereas I point out that this is a theory, or even a hypothesis.

    As for Polonium-218 vs. Radon-222, the fact that Radon-222 is an inert gas is actually taken as evidence *for* the case that Radon-222 is the cause of the haloes.

    • Okay, you prefer the idea that radon is responsible, even though (1) it’s inert and there’s no known way for it to concentrate chemically in radiocentres for long enough to form halos, and (2) there’s no peer-reviewed data supporting that identification. I just think that the evidence is against you.

  4. But again, the fact that Radon-222 is inert is claimed to be evidence *for* it to be the cause of the haloes … that’s what Brawley (not me) claims:

    “Radon is an inert gas, the only gas in the Uranium-238 decay chain, having the thermodynamic ability and more than enough time to migrate about in the mica, a few atoms at a time. Also significant is the apparent impossibility of distinguishing Radon-222 halos from Polonium-218 halos under the microscope.”

    All I am saying is that this is not at all a resolved problem (i.e. what causes the radiohaloes), while you pretend it is.

    • But as I’ve already argued, Brawley’s claim doesn’t stack up.

      Of course radon can migrate through mica – no one is disputing that. In fact the migration of radon is part of Snelling’s hydrothermal fluid transport model and attested to by the radiation staining along cracks and cleavage planes in the mica.

      But the critical point is that there is no reason why 500 million to 1 billion atoms of inert radon should then chemically concentrate into radiocentres to form halos – it’s only when it has decayed to polonium that there are the necessary chemical affinities to allow that to happen.

      Therein lies the fatal flaw in Brawley’s hypothesis and the reason why we can confidently conclude that polonium, based on the available evidence, is the source of these radiohalos.

  5. Brawley’s claims do stack up very nicely indeed !

    If you stick to the alpha-decay hypothesis (which is by no means proven either !!), then Radon-222 is the best candidate for causing the minihaloes you showed, if you read Brawley’s arguments carefully:

    As Brawley puts it:
    “There was therefore no reason to think that Radon manufactured in any nearby Uranium mineral particle (uraninite, betafite, uranophane, etc.) would stay attached to the disintegrating particle; an atom with a filled outer shell would not ‘attach’ to the biotite crystal’s atoms, nor would it be likely to remain attached to the disintegrating Uranium mineral inclusion. Moreover, with about four days to move around as single atoms subject to thermodynamic gas laws, it could wander literally anywhere in the mica permitted by the slightest crack, cavity, lattice discontinuity, or separation between crystal planes, “pushed” along by new Radon atoms forming back ‘behind’ it in the inclusion.”

    • I think you’re missing the point again. Brawley is right that the radon would not ‘attach’ to the biotite or anything else, and so would migrate. This is a point of agreement and part of Snelling’s model. However, for the very same reason that the radon will inevitably migrate (i.e. its chemical inertness), 500 million to 1 billion radon atoms would not be able to concentrate in one site in order to form a radiohalo. Unlike radon, polonium can concentrate in this way because of its chemical attraction to sulphur and other atoms, and we may therefore logically conclude that polonium, not radon, is the source of the halos.

  6. Brawley’s point is that the Radon atoms all migrate to the same place or places (away from where they were formed as a decay product), which is then the centre of the radiohalo. Where they go is determined by cracks, cavities, etc., as Brawley says. If they can’t go anywhere they contribute to the Uranium-238 halo (one of the rings).

    That’s his point, which I think you missed.

  7. What I said in my critique regarding the radon migration hypothesis is: “Migration of radon along fractures with hold-up points at tiny structural traps would result in exactly the same concentric ring pattern assigned by Gentry to polonium alone (because polonium is a daughter isotope of radon decay).” Brawley and Collins both noted that ring type halo structures lined up on visible fractures in the host mica. This is a physical, not a chemical process. It is well known that radon is a highly mobile atom – and hold-up of movement due to microscopic structural traps has many analogs in the geological world.

    Another problem with Gentry’s work is the assignment of specific alpha decay energies to measured rings of different sizes. Assume that you have an alpha emitting source in a crystal, and the the Bragg Effect causes the emitted alpha particles to deposit most of their energy in a narrow zone at a specific radial distance from the source. Over time you will get a spherical “damage” shell. Alpha particles of several different energies would be expected to form damage shells of differing diameters. When you cut through these shells, as in a thin section, you see circular structures – Gentry’s halos. You can only assign alpha decay energies (and their associated isotopes) to a specific circular halo if you know that you were looking at a radial cross section of the spherical damage shell. A radial cross section passes through the center of the sphere and thus shows the maximum diameter for the circular section. It is possible to cut a sphere along an infinite number of planes (e.g., thin sections) that don’t pass through the sphere’s center, and that result in circular features of smaller diameter than the maximum.

    Gentry never demonstrated that his measured halos were radial sections, and thus his assignment of alpha particle energies to any feature is hugely suspect.

    Regarding the incompatibility of proposed young-Earth models and the overwhelming evidence from radiometric age-dating, Gentry notes the problem and solves it by declaring that a miraculous event occurred. That miracle kept the decay rate unchanged for those Polonium isotopes Gentry used in his study, while accelerating the decay rates for every other radioactive species by orders of magnitude – and by widely differing amounts depending on the isotope. This acceleration would even have affected the uranium decay series of which Gentry’s polonium isotopes were a part. This scenario of course is patently absurd and has not one shred of evidence to back it up.

    Gentry’s hypothesis fails on multiple grounds.

    • This is in response to the two previous comments. We will examine, firstly, the claim that radon formed these halos, not polonium, and that it did so by accumulating in structural traps, and, secondly, the claim that the halos might not be radial sections and therefore the rings cannot be assigned with any certainty to particular steps in a decay chain.

      We have already established that radon is inert and there is therefore no chemical process by which it could have accumulated in radiocentres to form radiohalos. That point is now conceded. But what about the suggestion that radon might have accumulated in structural traps instead? Think about what is being proposed here. Some kind of unspecified structural trap in the halo-bearing mineral would have to stop the radon in a single spot (approximately a micron in width) for millions of years in order for 500 million to 1 billion radon atoms to accumulate and decay to form each radiohalo. But precisely how could that happen, especially in the case of a mineral such as mica? Mica has very strong cleavage planes along which radon would inevitably migrate, particularly in the presence of hydrothermal fluids. The evidence for the movement of hydrothermal fluids along the cleavage planes of halo-bearing biotite flakes is ubiquitous, including the presence of former fluid bubbles and the alteration of biotite to chlorite. In other words, Baillieul’s hypothesis is extremely far-fetched and really amounts to little more than ‘hand-waving’. We certainly need more specifics (preferably from published, peer-reviewed sources) before such an idea can be seriously considered.

      It’s also worth noting that many of those who have argued with Gentry in the past have not disputed his identification of the radiohalos. For example, G. Brent Dalrymple, former Deputy Director of the U. S. Geological Survey, famously testified in 1989 at the Arkansas creation trial that the polonium radiohalos were “a very tiny mystery”. Had Gentry misidentified the halos, here was the perfect opportunity for an expert to say so. The fact that Dalrymple did not do this, but rather conceded that Gentry had correctly identified the halos, speaks volumes. No doubt Gentry and Snelling themselves will be dismissed because they are creationists, but between them they have studied hundreds of thousands of halos and have accumulated far more expertise in this field than most of their critics.

      Next we come to Baillieul’s claim that the measured radiohalos have never been shown to be radial cross-sections, and therefore the concentric rings in the halos cannot be confidently identified with specific alpha particle energies. In fact, this criticism is easily countered by an examination of the experimental procedures involved.

      Snelling (2005) describes how the sheets composing the halo-bearing biotite flakes were progressively pulled apart using adhesive Scotch tape, and mounted on microscope slides. Tens of microscope slides were prepared for each sample, each with many (at least twenty to thirty) thin biotite flakes mounted on it. A minimum of thirty (usually fifty) microscope slides was prepared for each sample (at least 1,000 biotite flakes) to ensure good representative sampling statistics.

      Each slide was then carefully examined under a petrological microscope in plane polarized light and all radiohalos present were identified, noting any relationships between the different radiohalo types and any unusual features. The numbers of each type of radiohalo in each slide were counted by progressively moving the slide backwards and forwards across the field of view, and the numbers for each slide were then tallied and tabulated for each sample. Snelling notes: “Only radiohalos whose radiocentres were clearly visible were counted.” (p.114)

      This last point is very important for two reasons. Firstly, because it ensured that individual radiohalos were not counted more than once, and, secondly, because it ensured that the identified radiohalos were complete radial cross-sections. In other words, Baillieul’s statement is without foundation. Ironically, it is further refuted by the very photographs of Gentry’s radiohalos that are included in Baillieul’s own article, because in those photographs the halos’ radiocentres can clearly be seen, demonstrating beyond any doubt that they indeed represent radial sections.

      To sum up, there is no evidence that radon, rather than polonium, is the source of the observed radiohalos, because there is no viable physical or chemical mechanism by which radon could have produced them. Neither is there any substance to the claim that the measured radiohalos might have been misidentified because they do not represent radial cross-sections. Attempts to dismiss the radiohalo evidence for rapid granite formation and accelerated nuclear decay have once again failed to stand up to critical analysis and, from a uniformitarian perspective, Dalrymple’s “very tiny mystery” remains unsolved.


      Snelling A. A. 2005. Radiohalos in granites: evidence for accelerated nuclear decay. In: Vardiman L., Snelling A. A. and Chaffin E. F. (editors). Radioisotopes and the Age of the Earth: Results of a Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California and Creation Research Society, Chino Valley, Arizona, pp.101-207.

      • Snelling’s claim that he he has measured radial cross-sections needs to be taken with a large grain of salt. The statement that he chose only circular halos with observable centers does not mean that he found a radial cross-section – a small spherical or irregular grain may give the appearance of a point even at a significant distance away from the center of the halo sphere. When talking micron distances, the tape approach used by Snelling is like using a bowie knife to perform brain surgery.

        Also, Snelling doesn’t convincingly describe how he has determined the correlation of halo size with alpha decay energy. Biotite crystals have a range of densities and trace element abundances which will affect the depth of penetration by alpha particles. Gentry attempted to use a tunable alpha beam emitter at Oak Ridge National Laboratory to measure the penetration of alpha particles of specific energies into both fluorite and biotite. His results do not match the fine detail characteristics of the observed halos, nor is it possible to ascribe any depth penetration to a specific energy because of the diffuse nature of the “damage” zone Gentry created in his samples.

        Thus, the radon migration hypothesis is still a much more reasonable concept than that proposed by Snelling/Gentry.

        Oh, one other point. Having done extensive field work in the area of the Great Smoky Mountains that Snelling used as his sample area, I can state with confidence that these are not “primordial” rocks. Of course, the RATE group does not really define the term “primordial” (which is a century or more out of date and is not used by Geologists); Snelling’s assignment of rock units to specific ages is arbitrary and does not recognize the very large amount of research which has unraveled the geology of this region..

        Note from moderator: My reply to this post is lower down the page dated 30 June, 3.27 pm. It starts, “With the greatest respect…” For some reason that I can’t fathom, my reply won’t stay connected with Tom’s original post!

        • Note: This is in reply to Tom Ballieul’s post dated 29 June, 9.02 pm which begins, “Snelling’s claim that he has measured…” For some reason that I can’t fathom, my reply won’t stay connected with Tom’s original post!

          With the greatest respect, Tom, it is easy for “armchair experts” to dismiss the research of other scientists with hand-waving arguments, but you have yet to show that you can make a case that can stand up to peer review. Andrew Snelling has a proven track record in geological research, including the careful preparation, study and description of thousands of radiohalo-bearing specimens. Robert Gentry’s work on radiohalos was extensively presented in the peer-reviewed literature, including his work on correlating halo diameters with specific alpha-decay energies. Significantly, his identification of the halos was not challenged once by any of his peers at that time or since. If you think you have evidence contra Gentry, you ought to publish it in a recognised peer-reviewed journal rather than on TalkOrigins.

          I also wonder whether you have carefully read and digested the very research that you are seeking to criticise. I say this because your remarks about the rocks in the Great Smoky Mountains seem so off the mark. Where in any of his published material does Andrew Snelling ever claim that these rocks are “primordial”? Your comments also suggest that you have not properly read or understood my original blog post which was written expressly to point out that Snelling does not agree with Gentry that these are “primordial rocks”. The radiohalos are found in granites and metamorphic rocks that we think are Flood rocks, not Creation Week rocks as originally claimed by Gentry.

          To sum up, the claim that the polonium radiohalos were in fact produced by radon remains completely unsubstantiated, and has never passed peer review in any established scientific journal. By contrast, Gentry’s research was published in recognised peer-reviewed journals, and not one scientist who disagreed with Gentry’s interpretations ever in a peer-reviewed journal questioned his identification of the halos. Until such time as that case has been established, the polonium radiohalos remain a strong challenge to the conventional understanding of both the constancy of nuclear decay rates and the timescales required for granite formation.

          • Paul, I chose to review and critique Gentry’s work because I have specialized education and research experience in topical areas related to his work. Similarly, I have a professional background at least comparable to Snelling, and have done field work in the Great Smoky – Blue Ridge region. I can perform my critiques from my “armchair” because the young Earth arguments presented by these individuals can’t even pass a first reading.

            In Snelling’s work and publications on uranium for his Australian clients, he did not apply any of his Young Earth ideas. Why? Because they don’t describe reality. Snelling’s creationist writings – whenever they have been reviewed by his geological peers – have been thoroughly discredited. In this vein, Snelling’s arguments about the Geology of the Great Smoky Mtns area ignores the century or more of geologic field research by hundreds of geoscientists regarding the field relationships between the various rock units, depositional and emplacement history, tectonic movements, alteration history, etc. He ignores how long it takes for a sedimentary rock to be deposited, lithified, buried, altered to a metamorphic rock (whatever grade of metamorphism), maybe melted to form a migmatite or granite, and then exhumed from thousands of feet below the surface by the processes of tectonics and erosion. In short, his arguments are plain silly.

            Yes, Gentry’s initial studies on polonium halos were presented in several minor research articles in the journal Science. They attracted little attention because the phenomenon he described was just a curiosity, with no suggested application to the larger world of Geology or Mineralogy. Certainly Gentry avoided making claims that he had discovered evidence for a young Earth.

            The fact that there was no immediate critique of Gentry’s work in the 1970s is a reflection of the inconsequential nature of what he presented. It was only when the Creationist community started touting Gentry’s work as proof of a young Earth that scientists such as myself, Lorence Collins, and Richard Wakefield took a closer look. From different lines of reasoning we all found Gentry’s work to be fatally flawed. My critique was extensively peer reviewed both before and after being posted in the Talk Origins archive, as described on my web site (

            • First of all, let me apologise for taking so long to moderate and respond to your comments sent back in July. I’m rather behind with certain things, having spent several weeks over the summer away from home on field research, conferences and family holidays.

              As it happens, your messages arrived after I’d closed this thread to comments. I’d done that for three reasons. First, I was about to go away and knew I wouldn’t have time to moderate further comments for a while. Second, the issues on all sides seemed to have been pretty well aired by then and we were starting to go around in circles. Third, my intention has always been to keep discussions focused on the specific topic at hand (in this case, models for halo formation) and we were in danger of drifting away from that. I must confess that I’m reluctant now to re-open the thread, but in the interests of fairness I thought I would approve your comments and make just a few observations by way of response.

              If true, your hypothesis that the polonium radiohalos are, in fact, misidentified radon halos would have far reaching implications. I’m sure that G. Brent Dalrymple, for one, would be glad to have a solution to the problem that he described as a “very tiny mystery” back in 1981. However, your claims about the halos have yet to be made in the professional literature and subjected to peer review and informed criticism. Informal review for the Talk Origins website isn’t the same thing at all. Until such time as the evidence for this hypothesis is presented formally I find it difficult to take it seriously, especially when no obvious mechanism for concentrating radon into radiocentres is known to exist.

              Your claim that Andrew Snelling has simply ignored 100+ years of geological field research in the Great Smoky Mountains is likewise unsubstantiated. Indeed, the paper to which you allude actually describes the geology of the region based on precisely that kind of descriptive work. It was obvious from your earlier comments on that paper (29 June) that you had not read it properly or had misunderstood it, because you apparently confused Snelling’s hydrothermal fluid transport theory with Gentry’s ‘fiat creation’ hypothesis (which we agree is not consistent with the field data). Nor is it fair to say that Snelling simply ignores “how long it takes for a sedimentary rock to be deposited, lithified, buried, altered to a metamorphic rock”. He has, in fact, written on such subjects in a number of papers, e.g. here, here and here. Indeed, his radiohalo work (see here) sheds further light on the startling rapidity of the processes involved.

  8. Nice to have Tom Baillieul responding here on this blog – so I don’t have to repeat his arguments from the archive anymore.

    To me the evidence clearly stacks up to single out the Radon-222 isotope as the cause for the minihaloes discussed. I am not convinced at all by the arguments Paul Garner brings up.

    One thing Tom Baillieul brought up, and which is also discussed in Snelling’s piece, is the existence of Uranium radiohaloes. Quoting Snelling:
    “At today’s measured rates of radioactive decay, it has been estimated that uranium would have to decay for 100 million years to produce the uranium halos. That is at today’s decay rates.”

    So how does this fit in with the young-earth belief that this whole story is all about ?

    Snelling then says:
    “Alongside the uranium halos within granites, there is powerful evidence that uranium once decayed much faster during a global geological catastrophe! Let’s see that evidence.”

    And the evidence then is supposed to be …. the Polonium radiohaloes ! I do not get this at all – the existence of Polonium radiohaloes (which are not caused by Polonium but by inert Radon, as argued) does not mean the Uranium radiohaloes no longer exist.

    They are stil there! And they still took 100 million years to form, whether you have other types of radiohaloes or not, unless you start to play with Uranium decay rates (which physics does not allow you to do).

    • I think you’ve hit upon one of the reasons why there is such resistance to accepting the data collected by Snelling and others.

      In order to form, the polonium halos require an abundant supply of polonium – equivalent to millions of years’ worth of uranium decay at present-day rates. However, because the half-lives of the polonium isotopes are very short (Po-210 = 138 days, Po-218 = 3.1 minutes, Po-214 = 0.000164 seconds), the polonium had to be separated from the parent uranium very quickly before it could decay away. The implication is that millions of years’ worth of uranium decay had to take place in just a matter of days – millions of times faster than the same amount of decay would take to occur at presently-measured rates.

      The hypothesis of accelerated nuclear decay in the earth’s past is also supported by the documented systematic discordances between dating methods applied to the same rocks and minerals (Sm-Nd > U-Pb > Rb-Sr > K-Ar), and the retention of helium (a by-product of alpha-decay) in crustal rocks despite the rapidity of helium diffusion over geological timescales. To find out more, you’ll need to read the two technical RATE volumes (Vardiman et al 2000; Vardiman et al 2005), the layman’s summary (DeYoung 2005), or consult the various papers available on the Institute for Creation Research website.


      Vardiman L., Snelling A. A. and Chaffin E. F. (editors). 2000. Radioisotopes and the Age of the Earth: A Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California and Creation Research Society, St Joseph, Missouri.

      Vardiman L., Snelling A. A. and Chaffin E. F. (editors). 2005. Radioisotopes and the Age of the Earth: Results of a Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California and Creation Research Society, Chino Valley, Arizona.

      DeYoung D. 2005. Thousands…Not Billions: Challenging an Icon of Evolution, Questioning the Age of the Earth, Master Books, Green Forest, Arkansas.

    • Snelling’s statement – “At today’s measured rates of radioactive decay, it has been estimated that uranium would have to decay for 100 million years to produce the uranium halos. That is at today’s decay rates.” – raises several questions about the RATE claims in general.

      For radioactive decay rates to have varied over time means that the strong and weak nuclear forces which control alpha and beta decay would have had to vary. As these forces are two of the four fundamental forces in nature, their variation (especially to the extent that Snelling requires) means that matter itself would have been different (if it existed at all) in the very recent past. Of course, Snelling offers no evidence of this – because there is none, nada, zip.

      Also, Snelling fails to address the fact that you can’t have variation in the decay scheme for one radioisotope without it being systematic across all radioactive isoptopes (because of the fundamental forces controlling all radioactive decay). This means that the decay rates of hundreds of radioisotopes would have had to be accelerated by widely differing amounts to bring their decay schemes into agreement with a 6,000 – 10,000 year old Earth. There is no conceivable way for this to happen – and no evidence of any such occurrence. And as I pointed out in my critique of Gentry’s hypothesis – once you start proclaiming variable radioactive decay over time, you can’t arbitrarily hold one set of isotopes immune. Polonium decay rates and energies would have been affected along with every other radioactive species – and by unknown amounts. Thus, if Snelling claims that radioactive decay was significantly greater in the past, then he can’t ascribe his observed haloes to present-day alpha particle energies, nor conclude that they are due to polonium decay. Snelling’s arguments don’t hold up.

      Then there’s the little problem of heat. Geologists have known for decades that the interior heat of the Earth is largely the result of the continuing decay of the natural radioelements Uranium, Thorium, and Potassium (and all their radioactive daughter products). Energy in the form of heat is given off during every decay event, and the more rapid the decay rate, the greater the amount of heat generated. This is why reactor fuel elements continue to generate high levels of heat even after being removed from a reactor core. Under Snelling’s accelerated decay scheme to support a young-Earth hypothesis the Earth would still be completely molten – no oceans, no atmosphere, no people!

      This is why the scientific community doesn’t pay attention to the RATE group; their analyses don’t make sense.

      • Tom, if you’d like to find out what proposals the RATE group made concerning possible physical mechanisms for accelerated decay, I suggest that you read Eugene Chaffin’s contributions on that subject. He wrote a chapter in the original RATE volume (Chaffin 2000) and a follow up chapter in the results volume (Chaffin 2005). He also presented a number of interim reports in the literature and in conference presentations, for example here and here.

        You’re right to say that if decay was accelerated then different isotopes would have been accelerated to different degrees. In fact I addressed this point briefly in my earlier response to WebMonk. Among the evidence supporting the hypothesis of accelerated decay are the systematically discordant results yielded by different isotopic dating methods which were documented by the RATE group. Systematic discordances (not occasional discrepancies) are predicted by the hypothesis of accelerated decay, but difficult to explain if decay rates have been constant throughout geological history.

        It’s also true that short-lived isotopes such as polonium would likewise have been affected by accelerated decay, but as I pointed out in my reply to WebMonk, the acceleration factor would have been dependent upon both the type of decay (alpha versus beta) and the half-life of the particular isotope (the longer the half-life, the greater the acceleration). Thus, the decay rates of short-lived isotopes such as polonium would have been accelerated much less than longer-lived isotopes such as uranium.

        You also raise the question of whether the energies of the emitted alpha particles, and thus the radii of the resulting halos, would have been affected by accelerated decay, thus preventing us from correctly identifying the source of the halos. In fact, the alpha decay rate is extremely sensitive to the range of the strong nuclear force (Humphreys 2000 pp.357-362). What this means is that even a modest change in the range of the strong nuclear force might have resulted in order-of-magnitude changes in decay rates while the energies of the emitted alpha particles (and thus the size of the halos) would have been hardly affected (Snelling 2000 p.397).

        Like the previous objections, the issue of heat dispersal is also addressed at some length in the RATE publications. The RATE group see the generation of heat as a serious issue, though not necessarily an insurmountable problem. In the standard Big Bang model of the universe, an inflationary expansion of space is said to have occurred very early in cosmological history. Humphreys (2005 pp.67-74) has tentatively proposed that a similar episode of expansion might have occurred alongside the accelerated decay, resulting in cosmological cooling. In effect, the expansion of the fabric of space might itself have acted as a sink for the generated heat. It is hoped that creationist scholars with the necessary expertise will continue to investigate this and other possible solutions in order to construct testable models. At the present time, though, the mechanism of heat dissipation is one of the greatest outstanding questions raised by the hypothesis of accelerated decay – or indeed any young-age creationist model of earth history.


        Chaffin, E. F. 2000. Theoretical mechanisms of accelerated radioactive decay. In: Vardiman L., Snelling A. A. and Chaffin E. F. (editors). Radioisotopes and the Age of the Earth: A Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California and Creation Research Society, St. Joseph, Missouri, pp.305-331.

        Chaffin E. F. 2005. Accelerated decay: theoretical considerations. In: Vardiman L., Snelling A. A. and Chaffin E. F. (editors). Radioisotopes and the Age of the Earth: Results of a Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California and Creation Research Society, Chino Valley, Arizona, pp.525-585.

        Humphreys D. R. 2000. Accelerated nuclear decay: a viable hypothesis? In: Vardiman L., Snelling A. A. and Chaffin E. F. (editors). Radioisotopes and the Age of the Earth: A Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California and Creation Research Society, St. Joseph, Missouri, pp.333-379.

        Humphreys D. R. 2005. Young helium diffusion age of zircons supports accelerated nuclear decay. In: Vardiman L., Snelling A. A. and Chaffin E. F. (editors). Radioisotopes and the Age of the Earth: Results of a Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California and Creation Research Society, Chino Valley, Arizona, pp.25-100.

        Snelling A. A. 2000. Radiohalos. In: Vardiman L., Snelling A. A. and Chaffin E. F. (editors). Radioisotopes and the Age of the Earth: A Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California and Creation Research Society, St. Joseph, Missouri, pp.381-468.

  9. First off a comment on your moderation policy. You seem to have the habit of only accepting a post *after* you’ve written a response to it. You do not accept a post on its own merit, i.e. a valid argument that is on-topic, and contains no swearing, spam, etc. etc. (the latter being the reason most people moderate).

    I find that a bit irritating: it seems that if you cannot find an answer, you’ll simply ignore the response until you have one. You therefore do not allow others to read this *before* you reply.

    Anyway, back to the radiohaloes. You now wish to explain the Uranium radiohaloes by (radically) changing the decay rates over cosmic time. There is no physical evidence for this, nor compelling reason to do so.

    Again, radon is producing what you call “polonium radio-haloes”, which are not caused by polonium, and the problem you indicate therefore does not exist.

    I’m afraid that your references are not scientific publications, so I have no access to these, unfortunately (they are not in our library).

    • I’m sorry that you feel irritated by my moderation policy. However, if I feel that a comment warrants a reply I tend to hold off approving it until I’ve written one. I’d rather that visitors to the blog had the opportunity to read both together. But I have applied that policy even-handedly – whether the comment is critical of something I’ve written or not. Occasionally, a comment comes along that doesn’t require a reply and I just approve those straight away. Of course, delays are also inevitable sometimes simply because I have lots to do besides keeping the blog going. That, I’m afraid, is just a fact of life and I’ll have to beg everyone’s patience!

      To be honest, I don’t really see much profit in continuing our discussion about radiohalos, because you’re obviously convinced that they must have been formed by radon, rather than polonium, despite my best efforts to explain the evidence to the contrary. If the RATE volumes aren’t available in your library (and the evidence for accelerated decay is developed at length in those volumes), perhaps you could request them via an interlibrary loan?

  10. I appreciate your responses here Paul. Given your rebuttals to the counter-arguments, it must take a lot of effort to insist that you (and Snelling) are wrong. I can’t get past the fact that Radon is inert and there cannot accumlate in such concentrations as would be required to form radiohalos.

    Baillieul’s assertion that the Radon collected in cracks and such would require those collection sites (cracks) to remain undisturbed for millions of years. Sorry, that’s just not gonna happen.

  11. @Paul:
    Your moderation policy is not common in blogspace – why do you feel “that visitors to the blog had the opportunity to read both together.” ?
    That would mean you do not trust readers to be able to make up their own minds about responses from others, but that you need to help them somehow …

    And yes, I think radon is far more likely to be the cause of the radiohaloes, after reviewing all the arguments given.

    You state that collection sites cannot remain undisturbed for millions of years, with the argument “that’s just not gonna happen”.
    “Just” is not an argument, so could you elaborate on this ?

    Lots of things have remained undisturbed for millions of years, including dinosaur bones (not as strong as mica, I’d say).

  12. Eelco,

    Your complaint about Paul’s moderation policy is silly. You seem more concerned about securing an appearance of ‘being right’ – albeit temporary – than actually being right. In other words, you want to run around on the internet- for the few days that Paul would take to formulate an informed response – claiming a ‘victory’ in the debate because Paul ‘has no answer’ to your challenge.

    Think about it – you are complaining about having to engage in an informed debate. That speaks volumes…

  13. Paul:

    Count me as another person who greatly appreciates the moderation policy on this website.

    Posters here need to remember that this website serves to promote your book and your ideas, and the blog is a nice addition which allows people to publicly interact with you.

    If someone wants to post a question or criticism, it serves no purpose for that post to appear on your blog unanswered for an unspecified time, leaving the (false) impression that you have no answer for the issues raised.

    The fact that you screen all questions promotes civility (if the poster wants to see their post on your blog, that is). The kinds of discussions you are hosting on this blog often become heated, which needlessly muddies the debate. I am for any policy which encourages courtesy in these matters.

    Your policy also promotes thoughtful arguments, since any would-be posters know that their statements may be immediately followed by your rebuttal. Many blogs suffer from posters who overwhelm the discussion with sheer numbers of lame arguments or repetitive statements. Your blog encourages people to make their best case right off the bat.

    If you were in any way abusive, someone might have a complaint, but I have observed you to be very fair in presenting opposing arguments, and actually addressing the argument of your opponent, instead of getting sidetracked by their manner of address.

    Most Creationist forums are infested with Trolls, flooding the forum with excessive posting, attacking regular posters, making fatuous arguments, trying to impress others with their knowledge, making rude comments and badgering the moderator. In short, these types attempt to harass Creationists into silence rather than interacting with their ideas.

    Your blog encourages rational discussion, and discourages Trolls, and has thus been a pleasant oasis (so far). Don’t change a thing!

    God bless,

  14. I’m still picking up a lot of stuff, but something just occurred to me. Maybe this is a “well duh dummy” question, but I’ve made lots of them before and I’ll probably keep making them still.

    If there was a massive amount of accelerated decay, on the order of 100 million years in one year, wouldn’t this have an effect on the polonium decay too?

    Po-210 has 138 day half-life, normally. If that were cranked up by a factor of 100 million, that’s a half-life of 0.12 seconds, then 0.00000186 seconds for Po-218. There wouldn’t be any Po radiohalos at all away from their parent uranium atom.

    The fact that we do find Polonium (or Argon, whichever, same issue) well away and on their own puts the kabosh to the accelerated decay theory, doesn’t it?

    This seems like such an obvious thing that I must be missing something. If I see something stupidly obvious that everyone is missing, then I have usually found that I’m the stupid one.

    What’s going on here that I don’t see?

    • The answer is that the subatomic scale mechanisms for accelerated decay proposed by the RATE team would have produced different rates of variation for different isotopes.

      The amount of acceleration would depend on the type of decay involved (alpha versus beta decay) and the length of the half-life of each parent isotope. The longer the half-lives of the isotopes the greater the acceleration factor would have been. For short-lived isotopes, such as Po-210, Po-214 and Po-218, the acceleration of decay would have been negligible compared with, say, the acceleration of a long-lived isotope like U-238.

      This is consistent with, and confirmed by, the systematic trends in radiometric dating results observed by the RATE group, such that Sm-Nd > U-Pb > Rb-Sr > K-Ar.

      • You said there were suggested differences in the effect of the accelerated decay rate according to (1) whether or not it was alpha or beta decays and (2) the length of the parent’s half-life.

        The U, Ra, Po, and most of the other U238-chain decays are all alpha decays, so that’s not a difference. Where did something mention a difference in acceleration effect according to half-life? I didn’t see any statements by the RATE study that suggested alpha decay in U would be sped up more than alpha decay in Po.

        They even used the decay of Ra226 (three million times shorter half-life than U238) as an example of how much the alpha decay would be sped up. (pg 360) It certainly seems that if the accelerated decay sped up both U238 and Ra226, then it would also speed up Po210 (half-life only 4000 times shorter than Ra226). Why would Po be so much different than Ra in the effect seen from the acceleration?

        The mechanism they use there (the expansion of the atomic radius) would apply equally to all elements which undergo alpha decay, not just elements that have a “fast” alpha decay half-life. If anything it would vary according to the radius of the nucleus, not the parent’s half-life.

        Do you have some locations for information on why people suggest different elements’ alpha decay rates would vary from each other? All the stuff I read in RATE 1 seems to indicate that they would not vary from each other.

        Note from moderator: My reply to this post is lower down the page dated 30 June, 4.08 pm. It starts, “The mechanism for accelerated decay…” For some reason that I can’t fathom, my reply won’t stay connected with WebMonk’s original post!

        • Note: This is in reply to WebMonk’s post dated 29 June, 10.20 pm which begins, “You said there were suggested differences…” For some reason that I can’t fathom, my reply won’t stay connected with WebMonk’s original post!

          The mechanism for accelerated decay favoured by the RATE group would have produced different rates of variation for alpha-decay and beta-decay but would also have been proportional to the respective half-lives of the decaying isotopes. The longer the half-lives of the isotopes the greater would have been the acceleration factor; the acceleration would also have been greater for alpha-decaying isotopes compared with beta-decaying isotopes. It might help to take a look at the discussion on pages 5 to 6 of this interim report from 2003, and particularly figure 5 which sets things out graphically.

  15. Well, on the moderation policy: any positive response gets posted straight away, any critical one does not. This is very odd. Of course moderation needs to be done, to filter out spam, aggresive posts, swearing, etc., I am not complaining about that.

    Even though my response are polite and to the point, still my responses do not appear straight away, while others do, without reply from Paul.

    The comment from ‘Scott’:
    “You seem more concerned about securing an appearance of ‘being right’ – albeit temporary – than actually being right. In other words, you want to run around on the internet- for the few days that Paul would take to formulate an informed response – claiming a ‘victory’ in the debate because Paul ‘has no answer’ to your challenge.”
    is a very odd allegation. I would never run around the internet ‘claiming victory’, because ‘Paul has no answer’. Even if Paul would not have an answer does not mean there is no answer! It would be odd to claim that. Also, someone else could supply the answer. Paul’s moderation policy prohibits that.

    Finally, neither Paul nor myself can claim ‘victory’ in a scientific debate, as there *is* no victory to be had. Science is not politics.

    Then on to the accelerated decay: you say there is a subatomic scale mechanism for this. Does that mean you have some new physics in mind regarding quarks and gluons ? This really is non-standard physics, which of course is interesting, but there is no need for this. I would also like to see the motivation for such drastic changes to the physics of elementary particles …

    • Eelco, there’s really no conspiracy to approve positive posts and delay critical posts. I have applied the same moderation criteria across the board. Posts which don’t require a reply tend to get posted sooner (at least as soon as I get to them), whereas posts that need a reply, whether they’re positive or negative, usually take a bit longer so that both post and response can appear together.

      On the matter of possible mechanisms for accelerated decay, I refer you to one of my earlier replies to Tom Baillieul, which cites Eugene Chaffin’s research in this area. However, I would ask readers of the blog to direct any further questions about that particular aspect of the RATE research to Dr Chaffin himself. Theoretical subatomic physics really is above my pay grade!

  16. As ‘another reader with an opinion’ here’s what I think of the commenting policy. First, it’s great that you have commenting! It’s really annoying when blogs don’t, ’cause then you can’t see the any disagreements or controversy behind the post, so can’t really judge whether it is correct or not. Personally I trust posts (on a controversial topic like creationism) much more if I can read a discussion below it, as the post could be full of the author’s spin, or just plain wrong. So yeh, I was really pleased when I saw you allowed comments. And I see that moderation of comments is probably going to be essential to get rid of trolls.

    But I’ve got to agree with Eelco. Maybe it’s because I read a few blogs, but when I see a comment (especially a recent one) with no reply, I don’t think “that can’t be answered”, rather “I should wait for the reply for that” (unless I have something to say, although normally when I do I should shut my big mouth and wait for people who actually know things to say anything).

    The ‘only allowing comments when you have replied’ makes me a little suspicious that you could end up leaving a comment which you can’t reply for another day, and then another, and then forever. After all, we’re all human. For completeness I should probably say that it’s at least partly a gut reaction against what I *feel* is too much control and the stifling of discussion – although that’s blatantly not what you’re intending, and I fear I’m just be trying to back up my gut reaction with arguments, rather than consider both sides.

    Oh, and can I express my happiness that you have comments again?

    I have another point to make (unless it all makes sense while I’m half way through writing the post), but it’s about the subject in hand, rather than this tangent, so I think I’ll make that into a separate post. I hope that’s allowed.

  17. Actually, there are no systematic variations in decay rates – if there were they would have been noticed years ago by both nuclear physicists and geochronologists. There aren’t even systematic discrepancies between radiometric age dating results, because if there were, they would be obvious in ALL instances where radiometric dates with one isotopic decay scheme has been used to confirm another. From personal experience, I can confirm that this has never been observed. In fact, the Geologic community is working towards ever increasing sensitivity and accuracy in age dating.

    It appears that the RATE Group is up to their old tricks of culling through the literature to find age dates that appear to be discrepant, and for which the original researchers discussed why there may have been data outliers. They then ignore the reasonable explanations, and the very large number of data sets that have no discrepancies.

    Also, the explanation you (and the RATE group) give for variable decay rates over time makes no sense when held up against science’s current understanding of nuclear physics. You need much more than a few apparent discrepant age dates (because there are many factors which can affect the isotopic ratios within a rock unit or mineral grain). I also note that you don’t have a response to the comments that greatly accelerated decay rates would have changed the very nature of matter, or generated so much heat that organic life could never have formed. These have to be part of any RATE explanation.

    • Your claim that there are no systematic discordances between dating systems is not supported by the data collected and analysed by the RATE group. The RATE scientists collected samples from many different rock units. Following careful preparation, they were sent to conventional radioisotope dating laboratories for analysis. The results revealed clear discordances between the various radioisotope dating methods, such that the oldest ages were usually given by samarium-neodymium (Sm-Nd), followed by uranium-lead (U-Pb), then rubidium-strontium (Rb-Sr), with the youngest ages coming from potassium-argon (K-Ar). There is an identifiable pattern here: the isotopes which decay by alpha emission tend to give older dates than the isotopes which undergo beta decay, and the isotopes with longer half-lives seem to give older dates than those with shorter half-lives.

      Note that we are not talking about the RATE group “culling the literature” for discrepant dates as you allege; that comment suggests somewhat disconcertingly that you have not actually read the RATE research that you are criticising. Neither are we talking about an occasional discrepant result, or random scatter, but rather systematic trends in the data. Such trends surely cry out for an explanation. Of course you could, with some justification, point to the limited number of studies conducted by the RATE group and ask whether their conclusions are really more widely applicable. However, it does appear from closely examining other published literature that discordance is more prevalent than concordance. Wise (2002 p.256) has pointed out, for example, that a careful study of the National Geochronological Database (USGS Digital Data Series DDS-14, 1995), which contains thousands of examples of rocks dated with multiple methods, suggests that the methods rarely yield the same ages. It is possible that a statistical analysis of the radioisotope dates recorded in that database would confirm the systematic pattern of discordances reported by the RATE group, although such an analysis has yet to be done.


      Wise K. P. 2002. Faith, Form, and Time: What the Bible Teaches and Science Confirms about Creation and the Age of the Universe, Broadman and Holman, Nashville, Tennessee.

  18. Right. Actual question. What’s the nature of these cleavage planes wot radon migrates along? Could I ask for a far more detailed description?

    As far as I see it, an (I presume) far too simple model of them would be as perfectly smooth planes. Then the radon would spread out along the plane around cracks which it migrated to the plane by. You would get a circle of radon in the plane around the cracks, and enlarged radiohalos. These wouldn’t look like the radiohalos you’re talking about.

    If there was, say, a triangular area in a plane which radon could migrate around (with an open base), and an upward force acting on the radon, then you would get a radiohalo at the uppermost corner of the triangle. That would similar to a polonium radiohalo, wouldn’t it?

    So surely the nature of the cleavage planes, and any forces on the radon would determine if radon is a possible cause of the halos.

    Have I understood okay so far? And what are the planes like? And the forces on radon?

    P.S. Eelco, when Paul refers to the 2000 edition of “Radioisotopes and the age of the earth”, this can be found here. However, the 2005 edition (which is the useful one, as that actually contains the results) doesn’t seem to be on the internet. Annoying non-open-access-but-frequently-referenced publications.

    • I think these are good questions that need to be answered by those proposing the radon hypothesis for the radiohalos. Mica is a mineral exhibiting perfect cleavage, and radon would easily be transported along such cleavage planes, especially in hydrothermal fluids. Indeed, there is abundant evidence of hydrothermal fluid flows along the cleavage planes of the radiohalo-bearing biotite flakes examined by Snelling. However, we have not been presented with any evidence for structural defects in biotite that could act as radon traps in the way that would be required. Remember that these traps would have to stop 500 million to 1 billion radon atoms in exactly the same spot (only a micron in width) for millions of years to form each mature radiohalo. There is no chemical reason for the radon to be captured at these sites, and so far no-one has proposed a good structural reason either.

  19. I also find the moderation policy to be a bit of an inconvenience, but I understand why Paul has to do it. Without moderation, I fear the trolls would take over and overwhelm the civil discussions that take place here.

    I do find the “structural trap” idea to be a possibility that needs to be more thoroughly investigated. The fact that there are mica grains in Precambrian rocks that are virtually unaltered indicates that if such structural traps exist, they could persist for very long periods of time.

  20. Okay, folks, I’m getting ready to go away to the USA for a few weeks of field research and conference speaking, so I think it’s time to start drawing this thread to a close.

    It’s been very busy here over the last few days and this morning I woke up to find another ten comments on this thread needing moderation, several of which I’d like to respond to. What I propose to do is work my way through those ten posts, replying where necessary, and then we’ll call it a day on this subject (at least for now).

    Quickly browsing the comments in moderation, I think we’ll have aired the issues on all sides pretty well by that point anyway. I hope that sounds fair to everyone, and that no-one will feel cheated, but I’ve still got a conference paper to finish!

  21. Eelco:
    My point about the ‘collection sites’ not remaining for millions of years is pretty simple. For Tom’s argument to work, not only the cracks & crevices that he posits as the Radon ‘collection sites’, but also the ‘fluid migration paths’ that purportedly channeled the Radon-bearing fluid to them would have to remain all but absolutely static. This is because, as Paul has pointed out repeatedly, Radon is inert thus the only forces that would cause it to concentrate are physical (as opposed to chemical). Thus if the rock at these sites were to shift even a bit, these collection sites and ‘fluid migration paths’ would have been disrupted and concentration of Radon would thus cease at those sites.
    As for dinosaur bones remaining ‘undisturbed’, I think the issue of scale is important. The rocks in which dinosaur bones are embedded could shift some without destroying them whereas a shift of the same scale would disrupt Radon collection sites preventing further concentration due to the microscopic scale of the phenomena in question.

    This is reminiscent of the claims that some the layers of rock at the Grand Canyon are separated by millions of years, despite the fact that the boundaries between these layers are often knife-edge straight. The problem is that if the surface of a particular layer were exposed for any appreciable period of time (much less millions of years), erosion and other surface deformation would take place, precluding the possibility of the knife-edge boundaries that we in fact see.

    • Scott:
      so why should the mica *not* be able to remain intact (cracks in the same place and all) for millions of years, while dinosaur bones do ? The latter are far more fragile than the former, I would say.
      So I do not see why radon collection sites would be destroyed, while dinosaur bones would not. What difference in scale do you have in mind ?

      • Eelco,

        Regarding my comments about your ‘running around the internet claiming victory’, I was trying to make sense of your objection to Paul’s moderation policy (in my own mind). I don’t understand why it is a problem that Paul would postpone posting someone’s comment until he had a response. What do you (or any other reader) gain from seeing it immediately as opposed to a bit later with Paul’s response? I’m not saying your opinion is ‘wrong’, I just don’t see what the big deal is. From Paul’s point of view, I can see it as a means keeping an orderly comments section.

        Paul’s moderation policy doesn’t prohibit someone else from answering your question (I’m answering one of yours right now), it just prevents someone from answering your question before he does. Someone else can easily follow up after that.

        As to the scale issue I mentioned. Simply put, dinosaur bones are much larger than radioisotopes. A shift of a foot or so in a rock unit might well damage dinosaur bones but will not destroy them. The same shift would easily alter fluid migration paths and alter or destroy physical collection sites for Radon.

  22. Okay, I’m calling time on this discussion at this point. I think the main issues have been well aired from various perspectives. Of course, we may come back to the radiohalos again at some future date, but I won’t be approving any more posts on this thread. Now for that conference paper that I really ought to be working on!

  23. You could say then that radiohalos represent a case for the rapid coming into being of the earth, but don’t address the question of the age of the earth. Is that correct? Please comment on the significance of the radiohalos found in coalified wood Gentry reported. Is this a flood phenomenon?

    • The radiohalos provide evidence that the host rocks were formed rapidly, but do not imply instantaneous fiat creation of those rocks as per Gentry’s original hypothesis. The radiohalos reported by Gentry et al (1976) from coalified wood samples came from Mesozoic sandstones of the Colorado Plateau. Most creationists think these rocks were Flood-deposited. Gentry argued that the underdeveloped or embryonic nature of the uranium halos suggested that only a short time (thousands of years) had passed since the uranium infiltrated the wood. However, the time of infiltration from a conventional perspective must have been tens to hundreds of millions of years ago.

  24. [...] For a look at the differences between the two models, see Paul Garner’s discussion of them. [...]

  25. According to Gentry, there was no nearby sources of Uranium, that´s why he was confussed at first.

    • As discussed in Snelling (2000 p.447-449), there is a correlation between Po halos and immediately adjacent U sources, suggesting a secondary origin by short distance fluid transport of Po.


      Snelling A. A. 2000. Radiohalos. In: Vardiman L., Snelling A. A. and Chaffin E. F. (editors). Radioisotopes and the Age of the Earth: A Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California and Creation Research Society, St. Joseph, Missouri, pp.381-468.

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