New helium retention work suggests young earth and accelerated decay

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Originally posted by wehappyfew:
*note to edge: Humphreys' Tci equation is not made-up. He copied it from Wolf(1998) or independently derived it in a similar fashion. Either way, he should have given credit for it to Wolf (who called it the equilibrium age), and he uses it wrong (no surprise there, heh?).*

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Yeah, well, I figured I was going out on a limb there. But the whole argument is so contrived that I have to think that the closure interval business is just a red herring to cover up the fact that Humphreys really doesn't understand geological systems. I still don't see what it has to do with the ultimate age of the zircons. An equilibrium age may have been 1 minute or a million years... it really has nothing to do with how long the zircon has been around since the equilibrium age. If you have figured out what Humphreys is saying, I would love to hear an explanation. Somebody throw me a line...

edge,Read this:
http://www.agcrc.csiro.au/...cations/9900/melbourne/580.htmlIt looks like Humphreys' equations are correct, even if he doesnt use them right. If we plug in Reiners' diffusivity data, we get reasonable numbers for equilibrium age (millions to billions of years for the low temps, thousands to dozens for zircon above closure temp).
So we need to check Humphreys' diffusion constants against those reported by Reiners (which he claims as confirmation of the RATE experiments).All of Humphreys' paper boils down to a cumbersome restatement of the helium Partial Retention Zone concept, which is both age and temp dependent. Older means less helium (proportional to that produced), and hotter also means less helium is retained at an equilibrium of He production vs diffusion (assuming isothermal conditions). At a given temperature, the apparent age can never rise above the equilbrium age. It takes about 7.5 times the equilibrium age to arrive at that constant level. At that temp, older zirons appear to have retained less and less of the helium produced over their residence time at that temp.

"Somebody throw me a line..."
--I hope I don't get nailed for copyright infringment or something along that line, but these pages seem to be relevant:--Pgs 344-350; Radioisotopes & the age of the earth, Humphreys, 'Accelerated Nuclear Decay: A viable Hypothesis?'----------------->6. Helium retention supports fast nuclear decayOne of the strongest pieces of evidence I know of for accelerated decay is the high retention of radiogenic ⁴He in microstopic zircons. Figure 5 summarizes the data [Gentry et al., 1982b]. These zircons, about 75 microns long, are embedded in crystals of biotite (black mica). In turn, the biotite is embedded in hot Precambrian basement granodiorite (granitic rock) below the Jemez volcanic caldera near Los Alamos, New Mexico. Radioisotopic (Pb-Pb) dating of zircons recovered from deep boreholes in the formation give an age of "1.5 billion years" [Zartman, 1979].The surprising thing is this: although these zircons are tiny and were in hot rock, they have retained very large percentages of the 4He which the radioactive atoms in the zircons would have emitted by alpha-decay at normal rates over the alleged 1.5 billion years, as Table 3 shows. This is surprising to evolutionists because, over a billion years, they would expect most of the He to escape such small zircons by diffusion (He atoms wriggling through the crystal lattice), especially at high temperatures.Diffusion rates of radiogenic He through bare zircons, not embedded in other crystals, have been measured, as Figure 6 shows [Magomedov, 1970]. Those rates are too fast to retain the He for more than a few decades even at room temperatures. However, the biotite crystals in which the Jemez zircons were embedded could "bottle up" the He in the zircons, causing longer retention times. So the real question is: how fast does He diffuse through biotite?Unfortunately, I have found no measurement in the literature of He diffusion in biotite. However, there are measurements of argon diffusion in biotite, at least for high temperatures [Grove and Harrison, 1996]. Like He, Ar is a noble gas which does not chemically bond to other atoms. Argon atoms are larger and heavier than He atoms, so we would expect He to diffuse through a given material faster than Ar. That is, we can scale diffusion rates in any given mineral from the size and mass of the diffusing atoms [Fortier and Gilletti, 1989]. Argon and helium measurements on other materials support such scaling [Carrol, 1991]. From those data we can very roughly extrapolate the Ar-in-biotite data to He-in-biotite, getting a band of estimated He diffusion rates for biotite.We can then compare the scaled He-in-biotite rates to two simple models for the Jemez He retention:-Evolution model--steady low-rate radioactive decay, He production, and He diffusion for 1.5 billion years at today's temperatures in the formation.
-Creation model--a short burst of high-rate radioactive decay and He production, followed by 6000 years of He diffusion at today's temperatures in the formation.Next we can plug each of these models into the well-understood equations for diffusion [Carslaw and Jaeger, 1959, pp. 256-257]. For simplicity, I assume the zircons to be He-filled spherical cavities in the biotite. The cavity diameters are 44 microns, to match the surface areas of the zircons. Then for each temperature, I calculate what diffusion coefficient in the biotite is necessary to get the observed percent He retention in the zircons during the time allotted by each of the two models. Figure 7 exhibits the calculated model-required diffusion coefficients and their dependence on temperature. The small squares and finely dotted line show the He diffusion rates in biotite required by the evolution model to get the observed Jemez He retentions. The small filled circles and solid line show the He-in-biotite rates required by the Creation model to get the observed He retentions. The solid line at the left shows the observed high-temperature data for Ar in biotite. The dashed line joined to the solid line qualitatively shows the expected behavior of the low-temperature Ar data, excluding the effect of defects and impurities, which would reduce the slope of the right-hand part of the dashed line [Girifalco, 1964, p. 102]. The shaded band shows the estimated He-in-biotite data, and the Ar/He data in other minerals, especially muscovite [Lippolt and Weigel, 1988].The exciting thing about Figure 7 is this: the shaded band overlaps the Creation model and is far above the evolution model. That is, our estimates of what the experimental He-in-biotite rates should be are entirely consistent with a burst of accelerated nuclear decay only thousands of years ago. Moreover, the estimates exclude, by many orders of magnitude, the evolution model. That is, if the formation were really 1.5 billion years old, most of the He should have diffused out of the zircons.Of course, estimates are not as good as experiments. I propose that careful experimental measurements be done on He diffusion in the actual Jemez biotites. We can take the "He Creation Model" line in Figure 7 as an approximate prediction of what the experimental results would be if accelerated decay occurred. I say "approximate" because my Creation model is very simple. For example, it does not take account of possible changes in the formation temperature with time, nor does it take into account that the time since the burst of decay might be only 4300 years (from the Flood) instead of 6000 years (from Creation). But I would expect the simple Creation model to be within an order of magnitude of future experimental results if the accelerated decay hypothesis is correct.The evoluiton model I have used is also very simple; for example, it also does not account for temperature variations in the formation. But since the evolution model differs from the estimated He-in-biotite rates by four to five orders of magnitude, I seriously doubt whether any clever patches on the model could ever bring it into agreement with the shaded area.Figure 7 shows a clear difference between evolutionists and creationist predictions, one of which a well-performed experiment could resolve decisively. Future theoretical and experimental results on Ar-to-He scaling could also shed more light. In the meantime we have every reason to be optomistic. We could summerize the He retention data as follows:-Over a billion years worth of nuclear decay occured within thousands of years ago!
-Accelerated nuclear decay appears to explain the above summary very well.Figure 7
Predictions of yet-future experiments on He diffusion through biotite, using the observed He retention in Jemez zircons in two very different theoretical models. An evolutionist model (gigayear timescale) predicts the line with square points. A creationist model (kiloyear timescale) predicts the line with round points. The solid line shows experimentally-measured Ar diffusion in biotite [Grove and Harrison, 1996], extrapolated down by the dashed line from high temperatures to these temperatures. Rough extrapolations from those data using He and Ar diffusion observed in other minerals [Carrol, 1991; Lippolt and Weigel, 1988] suggest that the He-in-biotite measurements will fall into the shaded band shown. Thus He diffusion measurements in biotite are likely to reject the evolutionist model and confirm the creationist model.7. Other Data Support the Helium Retention Data
[Snip]

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Originally posted by TrueCreation:
--Pgs 344-350; Radioisotopes & the age of the earth, Humphreys, 'Accelerated Nuclear Decay: A viable Hypothesis?'----------

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"6. Helium retention supports fast nuclear decay

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"One of the strongest pieces of evidence I know of for accelerated decay is the high retention of radiogenic ⁴He in microstopic zircons. Figure 5 summarizes the data [Gentry et al., 1982b]. These zircons, about 75 microns long, are embedded in crystals of biotite (black mica). In turn, the biotite is embedded in hot Precambrian basement granodiorite (granitic rock) below the Jemez volcanic caldera near Los Alamos, New Mexico. Radioisotopic (Pb-Pb) dating of zircons recovered from deep boreholes in the formation give an age of "1.5 billion years" [Zartman, 1979].

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"The surprising thing is this: although these zircons are tiny and were in hot rock, they have retained very large percentages of the 4He which the radioactive atoms in the zircons would have emitted by alpha-decay at normal rates over the alleged 1.5 billion years, as Table 3 shows. ...

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Is Humphreys ignoring the fact that more He is constantly produced as uranium decays? Elsewhere, he has shown that the He concentration reaches an equilibrium state and can go no higher. So if the concentrations are so high doesn't that argue against his equilibrium limitation? Or does it mean that his diffusion calculations are way off?

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"This is surprising to evolutionists because, over a billion years, they would expect most of the He to escape such small zircons by diffusion (He atoms wriggling through the crystal lattice), especially at high temperatures."

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Actually, this is not surprising to me. I really do not see how the He concentration can depend solely on age. What is the driving force for He to 'wriggle through' the zircons? Does he realize that if He can exit the zircons, it can also enter them? Really, too many varibles for a dumb field guy to follow.

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"Diffusion rates of radiogenic He through bare zircons, not embedded in other crystals, have been measured, as Figure 6 shows [Magomedov, 1970]. Those rates are too fast to retain the He for more than a few decades even at room temperatures."

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But Humphreys has shown elsewhere that not all of the He diffuses away. It reaches an equilibrium concentration and stays there. Is there not a closure condition for He? If not then why are we even using this element as a clock?

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"However, the biotite crystals in which the Jemez zircons were embedded could "bottle up" the He in the zircons, causing longer retention times. So the real question is: how fast does He diffuse through biotite?"

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I'm not sure that I accept this as being the essential question.

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"...

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-Evolution model--steady low-rate radioactive decay, He production, and He diffusion for 1.5 billion years at today's temperatures in the formation.
-Creation model--a short burst of high-rate radioactive decay and He production, followed by 6000 years of He diffusion at today's temperatures in the formation."

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But above, we learned that the He could diffuse away from such small zircons in a matter of decades (Magomedov). Why is it now 6000 years?

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"...

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Over a billion years worth of nuclear decay occured within thousands of years ago!

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-Accelerated nuclear decay appears to explain the above summary very well."

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He must mean 'other than the fact that there is no evidence for accelerated decay.' How does it explain the heat generated by such accelerated decay? I'll try to look at this in more detail when I have more time. As yet, I do not see a compelling argument. Perhaps this is why He is not usually used to date rocks? Why are creationists suddenly attempting to do so?

edge,

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Is Humphreys ignoring the fact that more He is constantly produced as uranium decays? Elsewhere, he has shown that the He concentration reaches an equilibrium state and can go no higher. So if the concentrations are so high doesn't that argue against his equilibrium limitation? Or does it mean that his diffusion calculations are way off?

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Neither. Humphreys makes the case that these zircons are NOT at equilibrium. Given the diffusion rates he calculates and their current temps they must be currently losing more He than producing. Therefore we have a disequilibrium that can be dated.His diffusion calculations are correct, the question to ask is... where does he get his diffusion constants from (Ea and Do)?

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If not then why are we even using this element as a clock?

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Humphreys is trying to argue that the helium clock is good for only a few thousand years at these temps, therefore any zircons still containing He must be younger than that.

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But above, we learned that the He could diffuse away from such small zircons in a matter of decades (Magomedov). Why is it now 6000 years?

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Shhhh.... don't give away the ending.

Thanks for helping out TC,Is that an online or CD-based version or did you type all that in by hand?And what's the date on that edition? It mentions planned diffusion experiments that the ICR Impact 352 imply are already completed.I'd like to see that figure 6 that gives the 32 year old diffusion data from Magomedov. That is the only zircon diffusivity data mentioned anywhere in the several articles we have been discussing.Since TB seems uninterested, maybe you'd like to go over the calculations with us, TC? All we need is the most up-to-date zircon diffusivity data that Humphreys is using. Or we can use the Reiners data that Humphreys claims to confirm his experiments.Are you willing, TC?

"Thanks for helping out TC,Is that an online or CD-based version or did you type all that in by hand?"
--By hand, including the figures (yes they are accurate, give or take a pixel or two)."And what's the date on that edition? It mentions planned diffusion experiments that the ICR Impact 352 imply are already completed."
--We are approaching 2003 and the Radioisotopes & the age of the earth book is a 2000 publication. As the Impact-353 article hints on here:

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Two years ago it was reported that polonium (Po) radiohalos were still "a very tiny mystery."1 Since then, extensive research into the geological occurrence and distribution of Po, uranium (U) and thorium (Th) radiohalos has been undertaken as part of the RATE project,2 so now there are some preliminary results to report that are both significant and exciting.

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"I'd like to see that figure 6 that gives the 32 year old diffusion data from Magomedov. That is the only zircon diffusivity data mentioned anywhere in the several articles we have been discussing."
--Sure thing, here:
Figure 6. Helium diffuses very rapidly, within decades, out of bare zircons not embedded in biotite cyrstals Magomedov[/i], 1970. That suggests the surrounding biotite was the main restraint upon He diffusion out of the Jemez zircons.--Table 3 is also a reference in the above, so if it turns to be relevant:

Depth (km)	Temperature (oC)	Helium (cc/kg)	Retention (%)
0.95 ​ 1.17 ​ 2.90 ​ 3.50 ​ 3.93	105 ​ 151 ​ 197 ​ 239 ​ 277	86 ​ 36 ​ 28 ​ 0.72 ​ ~0.2	58 ​ 27 ​ 17 ​ 1.2 ​ ~0.1

"Since TB seems uninterested, maybe you'd like to go over the calculations with us, TC? All we need is the most up-to-date zircon diffusivity data that Humphreys is using. Or we can use the Reiners data that Humphreys claims to confirm his experiments.Are you willing, TC?"
--I can assess the problem, though I haven't fully been following the discussion as it pertains directly to He. Mind if you give a brief summery of the query & what progression has taken place?------------------

Thanks TC,It looks like those data are not the ones used in the recent Impact article 352. If we plug them into Humphreys equations from Humphreys refutes Meert, we don't get the same results. An activation energy of 15 kcal/mol is WAY too low for zircon, even for Humphreys.I've put out a call on several fora to try to get the latest diffusivity constants that Humphreys is using.But if you want to check Humphreys' results against Reiners data, look here:
http://www.geology.yale.edu/~reiners/zirconpaper040401.pdfTake the diffusivity measured by Reiners and plug them into Humphreys' equations.For more background, check out the rather technical discussion on T.O.
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In the thread titled:
helium in zircons means young earth?
The message number 43 (currently) by Chris Ho-Stuart 11/09/02 has a lot of good references.

wehappyIt's not that I'm uninterested I just have my doubts whether we'll be able to sort this out from the data we have. So, until its presented somewhere by Humphreys I was perpared to trust. If you can work out what's going on in between then that's great. If you really did present a carefully laid out summary of the ENTIRE story (and calcs you have done) I would be prepared to comment/check. I don't have time to do it completely independently however.

Fair enough TB,But since I am still learning all this myself, I don't have a comprehensive treatment prepared. And as you said, without Humphreys' raw data, we are kinda stuck.But we can evaluate Humphreys' claim that Reiners' data support his findings, can we not?What values do you get for equilibrium age (Humphreys calls it closure interval) using Reiners' data?

[QUOTE]Originally posted by wehappyfew:
For more background, check out the rather technical discussion on T.O.
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In the thread titled:
helium in zircons means young earth?
The message number 43 (currently) by Chris Ho-Stuart 11/09/02 has a lot of good references.[/B][/QUOTE]WeHappy...Thanks for the TO link. I think I can take consolation that at least some others were confused by Humphreys' byzantine logic and odd terminology. I really wasn't sure what he was saying. Now, perhaps, we can get down to the details.

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Originally posted by Tranquility Base:
wehappy

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It's not that I'm uninterested I just have my doubts whether we'll be able to sort this out from the data we have. So, until its presented somewhere by Humphreys I was perpared to trust. If you can work out what's going on in between then that's great. If you really did present a carefully laid out summary of the ENTIRE story (and calcs you have done) I would be prepared to comment/check. I don't have time to do it completely independently however.

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OK, time for an update. I suppose this will not be a "summary of the ENTIRE story", but we might consider it the first installment. As such, I hope you and TC will be kind enough to review it from the YEC perspective. I'm sure Joe and the rest of the evos will not be too shy to point out any errors I will surely make...The Story of Gentry and his ZirconsIn the beginning, a man named Gentry got ahold of some zircons from a geothermal energy test well in New Mexico. He measured the helium and lead contents, found no evidence of significant lead diffusion, and found helium concentrations like this (thanks to TC for the table):

Depth (km)	Temperature (oC)	Helium (cc/kg)	Retention (%)
0.95 ​ 1.17 ​ 2.90 ​ 3.50 ​ 3.93 ​ 4.31	105 ​ 151 ​ 197 ​ 239 ​ 277 ​ 313	86 ​ 36 ​ 28 ​ 0.72 ​ ~0.2 ​ ~0.2	58 ​ 27 ​ 17 ​ 1.2 ​ ~0.1 ​ ~0.1

From this data, he concluded that zircons would make a good place to store nuclear waste, since plutonium diffuses even slower than lead in zircon (which already diffuses incredibly slowly), and the lead hasn't had time to leak out even after 1.5Gya, as evidenced by the zircon data and calculated rates of lead diffusion.But the helium was another matter. The only diffusion data Gentry knew about was Magomedov(1970) whic gave an Activation Energy of 15 kcal/mol. Given a value this low, the helium should have quickly diffused out of these zircons at these temperatures. Apparently Gentry, working pretty far outside of his area of expertise, was unaware of even older research by Hurley(1952), Hurley (1954), Damon and Kulp(1957), and Damon and Green(1963) suggesting that zircon was pretty good at retaining helium at moderate temperatures except when heavily damaged by radiation.Regardless, Gentry, presented with the opportunity to re-evaluate his assumptions about zircon diffusivity, and thereby found a whole new branch of geology we now call thermochronology... instead chose to interpret this data as proof of his religious belief in a young Earth. Only five years later, Zeitler(1987) DID lay the foundations of thermochronology by studying apatite - another mineral that retains helium (although not quite as well as zircon).Fast forward a few years...
Gentry is still touting the "amazingly high" helium retention in his zircons...
and creationists like the Drs. Walt Brown and Russ Humphreys are citing Gentry's work as Young Earth evidence...
yet all the while, scientists like Zeitler, Wolf, Reiners, Farley, et al are applying the concepts of thermochronology to a wider array of new minerals and geologic settings and applications.Now here's where the story gets a little murky...Humphreys and his cohorts decide to study Gentry's zircons in more depth. They promise to commission new diffusivity experiments, construct elaborate mathematical models, make bold predictions based on those models, and gather it all up in a book called RATE. But the results of those promised experiments are yet to be published, the models are quite puzzling in their peculiar logic and obtuse language, and the predictions seem to bear little resemblance to real-world conditions.At this point it is difficult to discern what data Humphreys has gathered, what new data he has, what comes from very old sources like Magomedov(1970), and how he has combined it into a (presumably) coherent explanation of helium behavior in zircon.In the next installment, I will examine the few bits and pieces revealed so far by Humphreys in an effort to shed some light on what is going on behind the curtain at ICR.Stay tuned....
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.
.Refs:
Damon, P.E., and Green, W.D., 1963, Investigations of the helium age dating method by stable isotope dilution technique, Radioactive Dating: Vienna, IAEA, p. 55-69.Damon, P.E., and Kulp, J.L., 1957, Determination of Radiogenic Helium In Zircon by Stable Isotope Dilution Technique: Transactions of the Royal Society of Edinburgh, v. 38, p. 945-953.Gentry, Robert V., Gush, Gary L., and McBay, Eddy R., Geophysical Research Letters, Vol. 9, no. 10, p. 11291130, Oct 1982Hurley, P., 1952, Alpha ionization damage as a cause of low He ratios: Transactions of the American Geophysical Union, v. 33, p. 174-183.Hurley, P.M., 1954, The helium age method and the distribution and migration of helium in rocks, in Faul, H., ed., Nuclear Geology: New York, John Wiley and Sons, p. 301-329.Magomedov, S. A., Migration of radiogenic products in zircon, Geokhimiya, 2, 263267, 1970Zeitler, P.K., Herczig, A.L., McDougall, I., and Honda, M., 1987, U-Th-He dating of apatite: a potential thermochronometer: Geochimica et Cosmochimica Acta, v. 51, p. 2865-2868.

^ Nice summary (I think I would have been able to detect you are not a YEC from that discourse though ).

Double posting deleted.[This message has been edited by edge, 11-14-2002]

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Originally posted by edge:

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Originally posted by wehappyfew:
... But the results of those promised experiments are yet to be published, the models are quite puzzling in their peculiar logic and obtuse language, and the predictions seem to bear little resemblance to real-world conditions.

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And yet, we see on another thread that TC has written:

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"Catastrophic tectonics, flood surges, helium retention and a creationist cosmology IMO is the answer to your problems with YEC."

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Yep, proven!