Do Radiohalos in Tertiary rocks point to accelerated radioactive decay?

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That is a phenomenal article. Gentry was actually doing experiments. Give him serious credit for this!

Gentry’s own attempts to duplicate alpha particle damage in minerals using a helium ion beam illustrates this problem. An ion beam irradiates an “area” and has luminosities (particles per beam cross section per unit time) many orders of magnitude higher than the “spherical” volumetric emission of alpha particles from radioactive centers in mineral grains. Short exposure to an ion beam can create damage patterns equivalent to millions of years of low-level natural alpha exposure. Gentry (1974) notes the problem of beam intensity required to achieve a specific level of discoloration. In these experiments, the ion beam intensity was adjusted to produce a discoloration pattern in the irradiated mineral, with the extent (or depth) of the discoloration then being compared to the measured halo diameters in his thin section specimens. The pattern produced by Gentry through ion beam bombardment was a zone of discoloration, faintest near the source, and increasing in intensity up to a relatively sharp termination. Gentry’s ion-beam work, however, was not able to produce multiple bands or the sharply defined concentric ring structure of certain haloes. It is likely that intense alpha particle bombardment disrupts the crystallinity of the target mineral (a well known natural radiation effect), changing its physical properties along the particle path. This would tend to broaden the Bragg Effect rather than creating a narrow zone of disruption (that is, a “ring”).

And points to some really interesting open questions:

Odom and Rink (1989) examined giant radiohaloes in mica and proposed an alternative hypothesis for their formation. They compare the circular halo structures in mica with radiation-induced color halos (RICHs) in quartz. In the quartz crystalline structure, aluminum can occasionally substitute for a silicon atom, creating a slight charge imbalance. Alpha particles from uranium decay create hole-trapping centers around the aluminum atoms. This in turn creates a semi-conductive area where beta particles (also resulting from uranium decay) can cause diffusion and discoloration over a fairly large area. The width of the resulting halo can be correlated with migration of valence-band holes along a radiation-induced charge potential in the host crystal. While this is an attractive hypothesis, Odom and Rink cautiously note that the crystal structures and chemical composition of quartz and mica are significantly different. Quartz is known to have natural piezoelectric properties missing in the mica group minerals. Without further investigation, haloes caused by migrating hole trapping centers is speculative for minerals other than quartz.

Clearly, more work is required to resolve all of these questions. The association of ring-type haloes with any specific energy of alpha decay must be considered speculative.

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Found a good paper on the subject:

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I have one more question which relates to this topic:
I don’t fully understand how 214Po radio halos could be formed by radon migration or chemical replacement processes. The presence of only two rings in those samples indicates that they were formed by 214Po but this isotope decays so fast (half-life of only a few microseconds) that it cannot be transported anywhere. Its parent isotopes can travel through microscopic cracks but if this were the case, should we not expect to see more than two rings?
image

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Because the center of the ring is a radon trap. The radon doesn’t stay very long at any place along the crack except at the trap spot. You should also know that there is some question about how the rings were formed, and whether it involves polonium at all.

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This is from John Joly’s publication of Radioactivity and Geology in 1909. Fantastic work for the time, but the final paragraph in the chapter includes “Solar theory shows that the present supply of solar heat is difficult to account for even over this period”, meaning this work was done prior to even understanding solar fusion as the source of the sun’s warmth and the discovery of the neutron. That Joly’s chapter is a better introduction that what else is out there is an indication that an survey and synthesis update is probably in order.

I tend to agree somewhat. Sure he eschews pretty much all of geology to focus in on his particular area of study, but in contrast to most creation scientists armchair research which consists of misrepresenting the papers of other scientists, Gentry actually produced data which bears some investigation. These rings seem to have a story to tell, and without all the YEC pretensions, further work might add to the consilience of geological understanding. There does not seem to be a lot of recent, contemporary study brought to bear on these rings and their production. If that is because our understanding is already complete, I would love to see a synthesis which puts it all together.

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Well that is a diagram. What is it meant to represent?

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@swamidass It represents a naturally occurring Polonium-214 radio halo. Here’s a real life photo of a 214Po halo in biotite:
image
(provided by Lorence Collins).

Polonium 214 decays to Polonium 210, thereby creating the large concentric outer ring.
The decay of Polonium 210 creates the inner ring.

Polonium 214 has a half-life of only 164 µs. It decays so fast that it cannot survive granite crystallization. But the halo itself must have been created when the granite had already solidified. Robert Gentry used these halos to argue for the instantaneous creation of the granitic rocks in which they occur. Critics of this idea, like Thomas A. Baillieul, Lorence Collins and even Andrew A. Snelling pointed out that Polonium isotopes (and hence the radio halos produced by them) were likely derived from their parent isotopes (most notably Radon-222) which often intrude the rock via hydrothermal fluids during late stages of crystallization, travelling along fractures.

The decay chain looks like this: Rn222>Po218>Po214>Po210. The radio halo produced by the decay of Rn222 looks just like a Po210 radio halo - they are indiscernible from each other, even under a microscope. But here’s the problem: Po218 does create its own radio halo. So if the Po214 was truly derived from its parent isotopes which later came into the rock, why is the Po218 radio halo missing?

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Answer seems to be here: Do Radiohalos in Tertiary rocks point to accelerated radioactive decay? - #23 by T_aquaticus

They blurred together?

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Back to the point of the thread here. There seems to be a problem which needs to be addressed. Snelling says this,

“According to standard estimates, uranium must eject at least 500 million alpha particles to form a single dark radiohalo.”

Then this,

“…rare conditions were required to form the polonium radiohalos, and those conditions had to remain the biotite flakes for more than 100 million years at current rates of uranium decay, and this had to happen in granites all over the globe.”

Is this true? If true, then the entire so-called explanation given here is nothing more than a long-winded gloss:

http://www.csun.edu/~vcgeo005/revised8.htm

…because the author fails to address the proper concern raised by Snelling. True enough, Lorence Collins, the author, seems to accept the “transport theory” but he glosses over how conditions remained in place for 100 million years – time enough to transport the required radioactive particles to produce the haloes.

But apparently, even if such an explanation were provided, Snelling then brings up another problem. He says

“To dissolve and transport radon gas requires high temperatures, but such high temperatures would remove any evidence of alpha-particle decay. (In essence, the minerals were so hot the tracks left by alpha decay were erased.)”

Is this also true? If yes, then 100 million years of high temperatures utterly fails as an argument because apparently it would cancel the halo effect altogether.

I think I read somewhere years ago that geologists still do not have a good explanation for the presence of these radiohaloes. Can you offer one or cite a thorough explanation by a professional that addresses all points of concern raised?

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As we noted, there is no reference for this:

And of note, the is no reason to think:

Because this need not take place constantly for 100 million years. But this also neglects that we are talking about solid rock here. If the right configuration for transport exists, it will exist for as long as the rock exists. So…

That’s not true. Think fissures.

@r_speir, read this: http://apps.usd.edu/esci/creation/age/content/creationist_clocks/polonium_halos.html

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I found the following article to be an interesting discussion of the geological context in which halos are found. The gist of it is that Gentry’s claim is that polonium circles are evidence that the polonium was created complete with the rock in which it is found, but that cannot be, as there is evidence of prior history which attends the rock formations, “such as clastic grains, cobbles, ripple marks, mudcracks, bedding plains, and, most important, stromatolites.”
Gentry’s Tiny Mystery Unsupported by Geology

Snelling’s claims for halos are different, and he and Gentry did not see eye to eye on some of the implications of halos for creationism. I have not looked closely at Snelling’s views, but from what I have read of Snelling in the past leads me to say that I find Gentry to be sincere.
Gentry published some of the correspondence here:
Open Letter to ICR
As for as Collins’ article goes, boulders and terranes can easily be intact for >100 million years.

I think these halos are generally accommodated in conventional geology, with some interesting prospects for further investigation. They are far from some age of the earth take down. Imagine if the vast repository of geology and all the hundreds of thousand radiometric date measurements from the numerous isotope methods all converged to actually support a young earth. Then some old earth evolutionists found halos of uncertain origin and pronounced that all of that radiometric dating and geology supporting recent creation to be overturned on their basis. I would expect not many to recant their young earth conviction. In actuality, there is such depth and breadth to the geology around these halos which support an ancient earth that I would not indulge questioning the broader picture in contemplating them.

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This is what happens with the Rn222 and Po210 halos: They blur together. But why do we find three-ring Po218 halos and two-ring Po214 halos?
image
As Snelling said, Polonium-214 is gone in the blink of an eye! How can it be seperated from its parent isotope (Po-218) so that only two rings are produced? Or does this have something to do with the amount of Polonium that decayed in a given sample and the degree of discoloration created by this decay?

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From what @BrushyCanyon has explained, the differences could be explained by differences in the precise way the stones are displayed and the material of the stones. To really compare those photos, a lot more work would need to be done to ensure that it was properly controlled. As it is, that isn’t enough to make sense of the data.

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@Timothy_Horton To come back to the initially discussed question, what makes you think that Gentry made this stuff up? It’s been shown in this thread that he used experimental procedures to investigate how radio halos might be produced.

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I won’t. The whole thing is ridiculous given all the other evidence we have against accelerated radioactive decay. Just counting tree rings easily falsifies his position or other things like varves or ice cores. Or the entire history of geology. He has a presupposition that overwhelms other evidence and then he cherry-picks some random small phenomenon writing off other evidence.

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I agree that Gentry should not get serious credit. His investigation did not sufficiently explore alternative hypotheses, and completely ignored other sources of geochronological data.

That said, he was at least conducting experiments relevant to geochronology, which is more than can be said for many in the YEC camp. So I would say @swamidass has a point worth consideration, and Gentry should get some credit.

Best,
Chris

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My favorite, a quip I swiped from @paulbraterman:

For what it’s worth, radioactive decay constants are not free variables. They depend on things like time-dependent quantum mechanics, and the fundamental constants of nature such as Planck’s constant, the speed of light, and the charge on the electron. If any of these things had changed, so would the laws of chemistry, and we wouldn’t have rock formations laid down with recognizable structures. All this has been known since around 1928.

IIRC, these new laws of chemistry also would not allow life as we know it, killing everything before the released heat turned the Earth into a ball of molten magma.

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