The Politburo Diktat

Helium Diffusion Rate Dating

The latest Creationist "study" that claims to prove that the Earth is only 6,000 years old was performed by Ross Humphreys and his colleagues. He uses the diffusion rates of helium, escaping from some ancient zircons to "prove" a Young Earth. In a highly technical paper, he compares the diffusion rate of helium to the rates predicted: 1) by his "creation model," versus 2) what he calls the "uniformitarian model." Unsurprisingly, he claims that the data matches his creation model, and that the two differ by a factor of 100,000. In other words, if the earth is billions of years old, the data would match the red line (the "uniformitarian" or "evolution" model) . If only 6,000 years old, then the data would match the green line.

Isn't that an impressive chart?

But his paper is filled with errors and incorrect assumptions. It's bogus.

It took me, an educated layman, not a scientist, a long weekend to unravel them, which I could only do with Kevin Henke's detailed response. Following are the biggest problems with Humphreys' helium rate diffusion paper. Note that while 100,000 seems like a big number to explain, five compounding errors of a factor of ten can account for it (10 x 10 x 10 x 10 x 10 = 100,000) .

1. INTERNALLY INCONSISTENT MATH

Humphreys uses one set of equations for his "creation model" and another set for the "uniformitarian (or 'evolution') model." He should use the same equations for both models. He also uses an incorrect ratio of the measured-to-expected helium (the Q/Q_O ratio). Without correcting any of Humphrey's other errors, Henke used this internally consistent math and came up with an "ages" as high as 3,100,000 years. (See Table 6 near the bottom of Henke's document for the diverse “dates” that are possible from Humphreys’ equations.) Note that Henke does not accept any of these dates as the age of the Earth; they’re simply numbers that measure Humphreys' internal math errors and inconsistencies.

Internally consistent math could result in "dates" up to 3.1 million years. (While some of Humphreys' data may change again, at this writing, an average of the dates produced, using consistent math, gave 140,000, not 6,000 years, a factor of 20.)

2. CHANGED SOURCE DATA

Humphrey relies on source data that Gentry produced in 1982 in his study of these Fenton Hill, New Mexico bore site zircons. He blithely changes Gentry's helium measurements by a factor of 10.

Humphreys claims that he’s just correcting some “typos” in Gentry et al. (1982), but he never explains how and when these typos were discovered. It’s just so amazing that after Gentry’s data are “corrected,” they fall in line with Humphreys results.

3. IGNORED SOURCES OF EXTRANEOUS HELIUM

The study was all about residual helium found in zircons since they were formed. The idea is that a certain amount of helium was in the zircons originally, and that over billions of years, almost all of it would have diffused out by now. (Actually the zircons in question are dated at about 1.5 billion years old.) But Humphreys finds "too much" helium in them, and uses that to back into an age of 6,000 years for the zircons.

Sorry, but the Earth is a dynamic place. The Fenton Hill borehole site (where the zircons came from) is only one kilometer from the volcanic and helium-bearing Valles Caldera. The caldera formed 1.12 - 1.45 million years ago. The most recent volcanism associated with the caldera occurred roughly 130,000 years ago. Even "Young Earth Creationist" (YEC) Vardiman admits that volcanic events may release helium. Studies of the fluids in the caldera show that helium is still present. YEC Gentry, who gathered a lot of this data in 1982 even admitted "We are not certain whether the minute amounts of Helium recorded from the deepest zircons ... are actually residual Helium in the zircons or derived from some other source."

How much extra helium could have this nearby volcano have introduced? Five times as much? Ten times as much? One hundred times as much?

4. LABORATORY DIFFUSION RATES

This one is very good. Humphreys selected tiny zircons. Tiny? With a typical radius of 50 microns. Very tiny. Then the lab tested the helium diffusion rates of these samples, at various temperatures, in a vacuum. Reams and reams of data. But wait. Obviously, helium will more readily escape from a bare zircon in a rapidly heated laboratory vacuum than a deep subsurface zircon that is surrounded by minerals and high-pressure fluids. Furthermore, vacuums may decompose minerals and open fractures, which would allow helium to more readily escape than under natural subsurface conditions. Humphreys' own experimenter, Ken Farley warns that laboratory diffusion data must be carefully applied to natural situations:

"It is important to note that such laboratory measurements may not apply under natural conditions. For example, diffusion coefficients are commonly measured at temperatures far higher than are relevant in nature, so large and potentially inaccurate extrapolations are often necessary. Similarly, some minerals undergo chemical or structural transformations and possibly defect annealing during vacuum heating; extrapolation of laboratory data from these modified phases to natural conditions may lead to erroneous predictions."

In other words, diffusion rates obtained in a lab can't be compared to natural diffusion rates.

What's the error factor here? How much more rapidly will helium escape from tiny zircons isolated in a vacuum, than when surrounded by solid rock? Ten times as fast? One hundred times as fast? A thousand times as fast?

5. METAMORPHIC versus IGNEOUS ROCKS

This one is a little hard to believe. Gentry's original source data recognized that both igneous (granitic) and metamorphic rocks (gneiss) were included. The granitic "granodiorite" is below 2500 meters; gneisses and other metamorphic rocks occur above. Gneisses and granodiorites have very different origins, chemistries, and histories. The metamorphic gneisses, which have undergone high temperatures and pressures after the formation of their precursor rocks, would not resemble the granodiorites -- in helium retention or other properties.

Once again, one wonders what order of magnitude error is introduced by confusing metamorphic and igneous rocks. Five times? Ten times? One hundred times?

Remember the "factor of 100,000?"

   20 - for internally inconsistent math (20, or perhaps much more)
x 10 - for changed source data
x 10 - for extraneous helium
x 10 - for unrealistic lab diffusion rates
x   5 - for igneous vs.metamorphic differences
-----
100,000

Let me be clear. Apart from the first two errors, I cannot really quantify the order of magnitude of Humphreys' gross mistakes. He should. In the past, Humphreys has deflected criticism by claiming that such criticism is immaterial and insignificant. Or by suggesting that his critics perform their own studies, preferably peer-reviewed! Guess what? I am just some bozo on the internet. Based on that error-ridden study, that makes me Humphreys' peer. And that study has just been "peer-reviewed." If Humphreys' wants to do research on helium diffusion rates, it is his responsibility, no one else's, to apply scientific standards in that research.

All of the errors noted here were documented in much more precise, more extensive terms by Dr. Kevin Henke here.

For reference: Humphreys' 2003 study (pdf document) and Humphreys' rebuttal to Henke's criticism. Blogger Pigilito notes that the journal that published Humphreys' study "so lacks credibility that it is not listed in a database for determining publication impact factors."

Note: Humphreys' paper also claims to prove that the uranium lead (U/Pb) dates used by scientists are the result of 'accelerated nuclear decay" that supposedly occurred during "Creation Week" or "Noah's Flood." Since the U/Pb data incontrovertibly show A LOT of uranium has decayed into lead, the Young Earth Creationists have concocted an explanation of recent "accelerated nuclear decay." But, of course, this special event DID NOT affect helium, only lead. Got it? God turned on the magic nuclear decay machine early in earth's history, applied it selectively to some elements, but not others, and then HE shut it off. Right? ... I guess you had to be there.

Posted by Stephen at May 30, 2005 07:58 AM | TraktorBack (4)
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