Every quotation below was checked character-for-character against the file named with it. Where a source could not be obtained directly, that is stated. Full citations are in the literature review.
D. Russell Humphreys, in his own words
The 2000 prediction, which was about biotite
"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."
RATE Vol. 1 ch. 7, p. 346.
"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."
Same, p. 347.
"The theory needs to be worked out in detail, but we can already make some predictions. In particular, experimental He diffusion rates in Jemez biotite should turn out to be within an order of magnitude of the 'Creation model' line in Figure 7."
Same, pp. 374-375. The formal prediction.
"Predictions of yet-future experiments on He diffusion through biotite, using the observed He retention in Jemez zircons in two very different theoretical models."
Figure 7 caption, p. 348. The panel title inside the plot area reads "Diffusion in Biotite."
Moving the barrier from the mica to the zircon
"[The similarity Farley remarks upon made us decide that the biotite data were approximately correct. Because these data below 300 ºC were also about an order of magnitude higher than our creation model, we supposed that zircon might be a more significant hindrance to helium loss than biotite, so we turned our attention to zircon. It turned out that our supposition was correct, which makes it less important to have exact biotite data.]"
ICC 2003, Appendix B. RATE's own bracketed comment, and the hinge of the whole story.
"As we mentioned at the end of section 4, in our first Creation model we wrongly assumed that the zircons were a negligible impediment to the He diffusion. In this section we construct a new Creation model."
RATE Vol. II ch. 2, p. 46.
"This new model turns out to be very close to my previous Creation model—within 0.5% for sample 1 and 0.05% for the others—despite the different assumptions and equations. The effect of two changes (going from cavity in biotite to solid in biotite, and increasing the effective radius from 22 µm to 30 µm) almost completely canceled each other out. Thus my previously published predictions [Humphreys, 2000, p. 348, Figure 7] of diffusion coefficients still happen to be numerically valid—no thanks to me! But the numbers should be re-interpreted to apply to zircon, not biotite."
Same, p. 51. Humphreys correcting himself in print, on a point that costs him.
What the two model curves are
"In summary, the fifth column shows the zircon diffusion coefficients that would be necessary for the Jemez zircons to retain the observed fractions of He (third column) for 6000 years at the temperatures listed in the second column."
Same, p. 51.
"The points of that model are the values of diffusivity required to retain the observed amounts of He for 1.5 billion years at today's temperatures in the rock unit."
Same, p. 54. Neither curve is a prediction from physics; both are the same retention data divided by two assumed times.
How the defect line was drawn
"In Figure 15, the right-hand four points, the 175°C experimental point (solid dot) and the three points deduced from retentions and a 6000 year age (hollow squares and star) appear to make a fairly straight line. That suggests that below 175°C, the 'defect' slope has established itself."
Same, pp. 60-61. One measured point; three back-calculated from the age the line is used to support.
"Because our lowest measured value for D is at 175 °C, we extrapolated 24 °C down to the temperature of sample 2 but not further down to those of samples 2003, 1, or 2002."
Same, p. 56.
The claim, at its most confident
"Even in the defect region, the data agree quite well with the model. It is not often in science that experimental data so clearly validate a pre-published numerical model."
Same, p. 54.
"The average was 5681 years with a sigma (square root of variance) of 1999 years. We round off those numbers to 6000±2000 years."
Same, p. 56.
"Our assumption of constant temperatures is generous to the uniformitarian model."
Same, p. 52.
The blinding
"Through a small mining company, Zodiac Minerals and Manufacturing, we contracted with Kenneth A. Farley of the California Institute of Technology (Division of Geological and Planetary Sciences) to measure the diffusion coefficients of the zircon and biotite from the Jemez site. He is a recognized expert on helium diffusion measurements in minerals, having many publications related to that field. As we wished, Zodiac did not tell Farley they were under contract to us, the goals of the project, or the sites of the samples. We have encouraged him to publish his measurements and offered to send him the geologic site information if he does so."
ICC 2003, §5.
The failed runs, reported by RATE itself
"However, the values of D/a² he then obtained were over fifty times higher than all previous zircon data, both ours and data published by others. Scanning electron microscope images (Figure 10) revealed severe pitting and cracking in the HF-treated zircons."
RATE Vol. II ch. 2, pp. 42-43.
On Q0
"In his Appendix A Henke derives his value for Q0, 41 ncc/g ... He is in the right ball park, but he is probably using too small a value for the percentage of alpha particles ... The percentage came from Gentry's paper, but Gentry may have misstated what he meant by the number. From our own measurements of lead in zircons and my own very rough estimate of alpha particle losses, I got a Q0 considerably less than 25 ncc/µg. Gentry's original calculations are no longer available. But after discussing the matter with him, I'm inclined to think that even if he had an error in Q0, the error canceled out when he calculated the ratio Q/Q0."
Reply to Henke, trueorigin.org, 27 April 2005, item 6. The last sentence cannot work: Q0 is the denominator of Q/Q0.
On pressure — and an admission worth having
"All these factors strongly suggest that the diffusion rates in our zircons were influenced far less than one percent by removing them from underground pressures to a vacuum chamber."
Reply to Henke, trueorigin.org, 5 January 2006.
"As far as I know, nobody has measured the effect of pressure on helium diffusion in zircon."
Same. Still true in 2026.
On the heat, and on his own solution
"If Tmin were about 300 K during the Genesis Flood, then creatures aboard the Ark could stay warm. Though this is sheer guesswork now, I am confident that a good explanation exists (whether or not we can find it). That is because (a) the evidence convinces me that accelerated nuclear decay did indeed occur, and (b) as one of Noah's descendants, I know that his family did not freeze to death aboard the Ark!"
RATE Vol. II ch. 2, p. 74.
"The real problem is how to keep non-radioactive materials from getting too cold at the same time. I have not had time to pursue this part of the idea further, so here I can only outline a speculation that may turn out to provide a good explanation later."
Same.
"However, ⁴⁰K is a problem. Even though ⁴⁰K represents only about 0.01% of all the K we have in our tissues today (the other 99.99% is ³⁹K), that would be enough to kill Noah if he underwent more than a few million radioisotopic years worth of nuclear decay."
RATE Vol. 1 ch. 7, p. 373.
On the critics
"After seven years, the 'dogs of war' attacking a recent item of scientific evidence for a young world seem to have stopped barking."
Journal of Creation 24(1):14 (2010). Loechelt's 37-page technical paper had appeared thirteen months earlier and is item 12 of the article's own table.
"Amazingly, in his entire fifty pages he specifies only two real errors of mine: (a) I misspelled a name in one of my references, and (b) I was not precise enough in my geological description of a rock formation."
Reply to Henke, 2005.
The RATE group, collectively
"If God caused a period of accelerated decay during the Genesis Flood, it would have generated a massive pulse of heat in the earth. The RATE group estimates that the heating would have been equal to that produced by about a half billion years of decay at today's rates. But, it would have been generated over the period of only one year of the Genesis Flood. The heat would have melted the crustal rocks many times over unless there was some mechanism for simultaneously removing it quickly. How did the earth survive such a massive dose of heat without vaporizing the oceans and melting the rocks? How did Noah and his family survive such an environment on the Ark?"
RATE Vol. II ch. 10, p. 761.
"Humphreys' postulated explanation represents only a beginning attempt to understanding the complicated events of the Genesis Flood and may not, in fact, be the correct mechanism."
Same, p. 763.
"Had the granite plutons with their high concentrations of radioactive elements cooled at sufficiently high rates to form and persist as crystalline rock, then the oceans would have frozen solid had they cooled by the same amount. Likewise, Noah and his family on the Ark would have been in danger of freezing."
Same, pp. 763-764.
"However, at second glance there is a problem. It turns out shielding from the increased radiation dose from outside the Ark is not sufficient. Noah and his family may have had sources of radiation within their own bodies. For example, plants and animals today contain ⁴⁰K, which is radioactive. If nuclear decay rates were accelerated to the levels the RATE group believes occurred during the Genesis Flood, the radiation dose from similar levels of ⁴⁰K within Noah's body likely would have been lethal."
Same, pp. 764-765.
"The RATE group does not have a conclusive answer to this question, even after eight years of consideration."
Same, p. 760, on the theological problem.
"There are, of course, many questions and issues which the RATE project has not resolved. Although the problems were discussed at numerous times during project deliberations, adequate time and resources were not available to solve them."
Same, p. 758.
"This does not mean that we have solved all the problems, far from it. The primary concern openly admitted by the RATE group is the disposal of the large amount of heat if the decay processes were multiplied by a factor of one million or so during the Flood."
PSCF 60(1):36 (2008).
"To accuse the RATE group of deception and lack of integrity for concluding that the earth is young based on our evidence is like requiring Isaac Newton to delay publishing his law of Gravity because he could not explain the mechanism of gravitational attraction."
Same.
Eugene Chaffin, RATE's nuclear theorist
"For a 5 MeV change in the potential well depth, with the α-energy held exactly constant, the computer program shows that the decay constant will change by only one power of ten. If the α-particle is allowed to change by 10% or so, then the decay constant changes by about 10⁵. In Chapter 2 by DeYoung, it was shown that a change in the decay constant of the order of 10⁹ may be required, if the accelerated decay is restricted to the one year period of the Genesis Flood. Thus, these considerations seem to indicate that a one year episode of accelerated decay at the time of the Flood may not be enough."
RATE Vol. 1, p. 307. RATE's own theoretician conceding a four-order-of-magnitude shortfall, in RATE's own first volume.
Robert Gentry, whose data started it
"For the other zircons from the granite and gneiss cores, we made the assumption that the radiogenic Pb concentration in zircons from all depths was, on the average, the same as that measured (Zartman, 1979) at 2900 m, i.e., ~80 ppm ... this means there should be ~7.7 atoms of He generated for every Pb atom in these zircons."
GRL 9(10):1129 (1982). The Q0 recipe, in full, as published.
"The uncertainties in our estimates of the zircon masses and compensation factors probably mean these last values are good only to ±30%."
Same.
"In fact, considering the Precambrian age of the granite cores (Zartman, 1979), our results show an almost phenomenal amount of He has been retained at higher temperatures, and the reason for this certainly needs further investigation for it may well turn out to have a critical bearing on the waste storage problem."
Same, p. 1130. An honest flag of an anomaly. Not a young-earth claim.
"In fact, at present we are not certain whether the minute amounts of He recorded from the deepest zircons (3930 and 4310 m) are actually residual He in the zircons or derived from some other source."
Same. Those are RATE's samples 5 and 6.
"Because it has been suggested that temperatures in the granite formation are rising, we do not know precisely how long the zircons have been exposed to the present temperatures."
Science 216:296 (1982). The most important sentence in the whole dispute, written by the man whose data the argument rests on, twenty-three years before RATE assumed a constant temperature.
"Frequently, there were significant differences in the U and Th concentrations from two different locations on the same zircon."
Same, p. 296.
"The near equality of the He concentrations in the surface and 960 m depth zircons is not particularly meaningful because the surface zircons were from an entirely different geological unit and doubtless have different U—Th—Pb concentrations than the zircons from the core samples."
GRL, 1982.
Gary Loechelt
"below 300 °C, which is the temperature region of interest, the diffusivity of helium in biotite is 2-3 orders of magnitude higher than that of zircon."
"Fenton Hill Revisited," §3.3. RATE's own biotite data, against RATE's own boundary condition.
"Yet, in a classic bait and switch maneuver, this approximation is applied only to their young-earth creation model, and not to their old-earth uniformitarian model. In the old-earth model, the effect of the surrounding biotite is neglected altogether."
Same.
"Ironically, the helium diffusion study and the polonium radiohalo study are published as consecutive chapters in the same book."
Same, on RATE needing the same biotite to be permeable to radon and impermeable to helium.
"Therefore, the figure depicts a heating (not cooling) event in which the temperature rises to maximum at a square root time of 600. Humphreys apparently read this figure backwards, supposing that time advanced from right to left instead."
Same, §3.4. The original figure could not be obtained for this article.
"The combination that best fits the measured data is a multi-domain diffusion model in the context of an old earth with multiple thermal events occurring over the last 1.44 billion years."
Same.
"The young-earth model goes from excessive depletion to excessive retention. With the more retentive multi-domain diffusion model, there is now insufficient thermal budget in a young earth to cause enough helium loss."
Same. Loechelt reporting that his own kinetics break the young-earth model in the opposite direction.
"This value is not well constrained by the experimental data, and reasonable fits could be obtained for fractions ranging from 0.1% to 10%."
Same, on his own key parameter.
"these choices for the geometry and boundary conditions have the effect of accelerating the loss of helium from the crystals, effectively making the diffusion age appear younger. Therefore, one cannot accuse me of being biased in my choice of corrections to the RATE model."
Same.
"Without a failed old-earth model, the case for accelerated nuclear decay becomes a circular argument: assume accelerated nuclear decay, match the retention data, and thereby conclude that accelerated decay has occurred."
Same.
"For a highly tunable model to exactly match a preliminary dataset is suspicious, not impressive."
2009 response.
"The very thing that Humphreys criticizes, multiple people who are unrelated and unknown to each other bringing their different and sometimes conflicting ideas to the table, debating and even disagreeing with one another, is how true science works!"
Same.
"The editor strung me out for over a year, leaving me the impression that my manuscript would be accepted as long as I agreed to certain changes. However, whenever I submitted a revision for his approval, he would raise new objections to the paper. After over a year of effort it became clear that the CRSQ was not going to publish my paper under any circumstance. Incidentally, the physics section editor at the time was also one of the three main editors for the RATE books, which raises serious conflict of interest concerns."
Same. A first-person allegation about the Creation Research Society Quarterly, reported here as such.
Kevin Henke
"Using the available information from Gentry et al. (1982a) and ignoring the possibility of extraneous 4He and 3He, I was unable to derive a Q0 of 15 ncc STP/µg for the zircons. Instead, I found that the assumptions in Gentry et al. (1982a) yield a Q0 of 41 ncc STP/µg."
June 2010 essay.
"In contrast, Reiners et al. (2004, p. 1859) describe a as the 'average half-width of the tetragonal prisms' ... The width of a tetragonal prism may be readily determined by sieving, whereas the lengths cannot (this is why you can push a long strand of uncooked spaghetti through a window screen, but not a piece of typing paper)."
Same.
"While Wolfe and Stockli (2010) recently demonstrated that helium diffusivities determined by measurements in a laboratory vacuum were able to suitably predict helium retention in their zircons, Dr. Humphreys has yet to show similar results for his defect curve and its associated creation model."
Same. A concession more decisive than Henke allows.
"Dr. Humphreys falsely believes that if the helium concentrations in surrounding biotites are now relatively low, then these concentrations must have always been low in the past."
Same.
Rodney Whitefield
"The reported U and Th content values for 3,930 and 4,310 meters can be averaged and compared with the averaged values reported for the 960 meters depth. When this is done the result indicates the Uranium and Thorium content at 960 meters is 9.17 times greater than the averaged content at those lower depths. Applying this factor to increase the amount of helium to be expected at 960 meters, one obtains a smaller retained helium fraction of 0.062."
"22,000 °K? Really?" (2008).
"As a consequence, the 102 million year cooling age date for the zircon is consistent with the 62 million year apatite fission track cooling age. Sphene fission track data indicate that the rock had not been hotter than about 250 °C for the last 1,300 million years."
Same. The cross-check that did not have to come out right.
"The closeness of these two values, and the known presence of biotite as an attached contaminate on the zircons, reveals that the major portion of the helium measured below 255 °C derives from biotite."
Same, on 13.9 kcal/mol for the zircon low-temperature segment against 11.4 for GT-2 biotite.
Timothy Christman
"The results of helium measurements from these detrital samples are significant because there is no conceivable scenario for those zircons to have been exposed to elevated temperature (>100 °C) during the last 6000 years. These sediments must have been eroded from near the surface in the mountains of northern India."
2005 critique.
"RATE certainly has no grounds to declare the entire science of radiometric dating to be invalid based on a study that apparently involved only two published diffusion tests (only one of which actually showed the low temperature fast diffusion rates essential to their 'theory')."
Same.
Randy Isaac
"However, the data presented were taken in conditions of laboratory vacuum and actual diffusion rates in field conditions are known to be considerably lower, by as much as a factor of one thousand or more."
PSCF 59(2):145 (2007). The 2007 essay review contains no footnotes and no references of any kind. The figure is asserted without a source, and cannot be recovered from the physics.
"However, claims that scientific data affirm a young earth do not meet the criterion of integrity in science. Any portrayal of the RATE project as confirming scientific support for a young earth, contradicts the RATE project's own admission of unresolved problems. The ASA can and does oppose such deception."
Same, p. 146. The line RATE reacted to hardest.
"It is not at all clear that Gentry's theoretical concentration of helium can correctly be interpreted as an initial concentration Qo of helium. If so, how did Gentry make that calculation? What were his assumptions?"
PSCF 60(1) (2008).
The mainstream literature
"In summary, the zircon (U-Th)/He thermochronometer has a closure temperature of 170 –190°C for typical plutonic cooling histories"
Reiners et al. 2004, abstract.
"Between 1.2 × 1016 α/g and 1.4 × 1018 α/g, the frequency factor, D0, measured in the c-axis parallel direction decreases by roughly four orders of magnitude, causing He diffusivity to decrease dramatically (for example by three orders of magnitude at temperatures between 140 and 220 °C). Above ~2 × 1018 α/g, however, activation energy decreases by a factor of roughly two, and diffusivity increases by about nine orders of magnitude by 8.2 × 1018 α/g."
Guenthner et al. 2013, abstract. The Fenton Hill dose computes to 1.98 × 10¹⁸ α/g.
"Experiments at 20 kbar yield diffusivities lower by about an order of magnitude and correspond to an activation volume of 14 cm3/mol."
Harrison et al. 2009, abstract. The measurement that ends the vacuum objection — in Humphreys' favour.
"Annealing of the haloes is first observed in samples from a depth of 1850 m (134°C present temperature) and is complete in samples from a depth of 2120 m (151°C). The observed temperature of annealing of the haloes is in good agreement with earlier observations of fission track annealing in apatite from the same core samples."
Laney & Laughlin 1981, abstract. Two independent thermometers in the same cores, both saying the deep rock is hot now.
"A much more drastic reduction of apatite fission-track ages occurs whereby all samples below a depth of 6000 feet (1800 m) have effectively been reset to 0 m.y."
Zartman 1979, p. 4.
"No reasonable fits to the measured geotherm were obtained for source ages significantly in excess of 40 ka. Thus, if the deep gradient increase in EE-2 is due to conductive heating from a source below Fenton Hill, the source is constrained to be young, much younger than the Valles caldera."
Harrison, Morgan & Blackwell 1986, quoted verbatim by Loechelt. The paper itself is paywalled and was not obtained for this article.