Wednesday, March 31, 2010

R.A.T.E. and Carbon-14 Dating

In the first RATE book (Volume 1), it was formally decided that any research into carbon-14 dating should not be done as it was not as relevant to the overall aim of researching radioisotopes with long half-lives. However, with a highly successful fundraising campaign, they apparently had a change of heart before the second book was to be published. Carbon-14 became a priority once again, and they did a research project on it that was probably the most interesting out of them all.

John Baumgardner did the presentation paper on 14C. To research the effectiveness of radiocarbon as a geologic clock, he turned to one of creationism’s oldest tricks: dating zero-sum samples. This is a tactic with a long tradition, going back to the 1960’s and 70’s, when recently deceased mollusks would be sent to laboratories to be carbon-dated, and they were found to be 2,000 years old, or more, in radiocarbon years.(1) (Isaac, 2005) Penguins or other Arctic/Antarctic creatures would sometimes also be used, ignoring the fact that ice is a repository for Carbon-12. For this test, however, a different kind of zero-sum was used. Instead of recently deceased samples, Baumgardner looked to the other end of the timeline, and dated extremely old samples. Coal, in fact.

It sounds absurdly simple: Do a radiocarbon date on a lump of coal, and because it’s so old, there should be virtually no 14C present. But the idea of doing a 14C date on a sample which should be completely radiocarbon-dead is not new. Creationists had claimed 14C trace-amount discrepancies inside coal and oil ever since at least the early 1970’s. (Whitelaw, 1970) But it had been noticed by other, more secular, scientists that trace amounts of radiocarbon were to be found in samples which are clearly far older than 50,000 years, even after the development of more accurate equipment, such as acceleration mass spectrometry, or AMS. Baumgardner has no end of fun in citing these sources in the opening sections of his paper. For example, he cites an article published by German scientists at the University of Kiel, stating how a barrier of 40,000 years could not be breached in dating the shells of foraminifera in sea-floor core samples due to apparent 14C contamination whose origin could not be determined. (Nadeau, et al., 2001) Another article cited openly states how “contamination” (Baumgardner’s quotation marks, not mine) is named as the cause of inaccuracy beyond the 40-50 thousand year mark. (Bird, et al., 1999). He even lists an exhaustive table detailing major scientific journals and the results of their radiocarbon measurements on samples deemed to be older than 100,000 years.

At this point, Baumgardner has successfully made his case, and no experiments really need to be done. But these cited sources do not simply establish the awareness among geochronologists of the problem. They also establish that the RATE team was well aware of this type of phenomenon, and saw an opportunity to use it.

For this study, samples of coal were obtained form the U.S. Department of Energy Coal Sample Bank maintained at Pennsylvania State University. These had previously been collected in 180kg quantities from recently exposed areas of active mines, placed in 115 liter steel drums, and then were purged with argon. The samples were then processed into representative 300g samples with .085mm particle size, and sealed under argon in foil multi-laminate bags. Ten out of 33 available coal samples were selected. These were then taken to “one of the world’s best AMS laboratories.” Baumgardner does not say which one, tacitly implying that there may be some legal consequences if it were named. The samples were combusted into CO2 and then converted to acetylene using a lithium carbide synthesis process. The acetylene was then dissociated in a high voltage AC electrical discharge to produce a circular disk of graphite on spherical aluminum pellets, which were to be the “targets” of the AMS system. Each target was then analyzed on 16 different spots as a variance check to help reduce any potential contamination of the sample. Four measurements were then done on each of the ten samples, with a standard background of 0.077±0.005 pMC (that’s percent of modern carbon) applied.

The results? Not surprisingly, trace amounts of 14C were found. In pMC the results ranged from 0.163 to 0.492. Faint traces, to be sure, but traces nevertheless.

So, Baumgardner showed that this discrepancy was much more than academic references to the scientific literature. It really was there. But the RATE team wasn’t quite done beating this dead horse just yet. Not content with their results on coal, they included another set of samples even more devoid of original radiocarbon – diamond!

About 50mg of sub-millimeter diamond chips were cut from a diamond obtained from the Kimberley district in South Africa. The sample had been shattered using a sapphire mortar and pestle. The diamond chips were then included with the ten coal samples sent to the unnamed AMS laboratory. These proved to be a challenge for the lab, since it had never before attempted to oxidize diamond. However, they were eventually successful, even though the results took considerably longer.

And those results? There were traces of 14C detected as well. This time, results on six measurements ranged from 0.1 to 0.15, ±.03, but no standard background correction was applied this time. These results, Baumgardner tells us, are statistically equivalent with the values given by the coal – approximately 0.12 pMC, or roughly the equivalent of 55,700 years. This, he says, confirms the accelerated decay model. Clearly, the reason these coals and diamonds are still showing some minute traces of age is because they aren’t the millions of years they are purported to be. Rather, they stem from the catastrophic geotectonic events surrounding the Flood event, with much of the coal stemming from the buried organic material which resulted.

The anomaly in 14C radiometric dating that Baumgardner helps unveil is interesting. But the conclusions he draws from them are questionable. The implication is that the 55,000 RCY produced in these 14C measurements somehow actually indicate a real age of something around 6,000. But Baumgardner cites the wrong sort of evidence for this. Were his scenario true, the accelerated decay, which he and every other RATE researcher seems to have decided took place during the Flood, and not the Creation Week, would have happened about 4,400 years ago – the time Biblical scholars have calculated that Noah’s flood happened. That means that 14C dating should show a consistent half-life pattern on all samples between modern-day and 4,400 years ago, but then suddenly leap into absurdly old ages on anything older than that. In other words, charcoal from, say, a Phonecian campfire, dated by other methods to be 5,000 years old, would yield a radiocarbon date of over 50,000 years! Baumgardner, however, cites nothing like this. Also, the trace amount of 14C does not quite fit the revised timeline of accelerated decay. As Baumgardner himself notes, any value of alpha decay large enough to produce 500 million years worth of decay in 87Rb with a half life of 48.8 billion years would entirely wipe out any and all 14C that might have been present before such an event occurred. In other words, coal and diamond should be radiocarbon dead anyway! His response?

"An important issue then arises as to how an episode of accelerated decay during the Flood might have affected a short half-life isotope like 14C. The surprising levels of 14C in fossil material from organisms that were alive before the cataclysm suggests that perhaps only a modest amount of accelerated 14C decay took place during the cataclysm itself, an amount insufficient to eliminate the 14C that existed in these organisms prior to the cataclysm. Accordingly, we here offer the tentative hypothesis that, whatever the physics was describing the decay acceleration, it did not operate in so simple a manner as to reduce temporarily the effective half-lives of all radioisotopes by the same factor." (Vardiman, et al., 2005:620)

The solution, it seems, is more fantastic than the puzzle!

Some procedural problems are noteworthy in Baumgardner’s work. For example, he doesn’t include the standard background of 0.077±0.005 pMC in his results for the diamond chips. Why did he do this? He fails to say, but one can surmise he did so in order to present results that looked more similar to his results on coal. Also, if a true test for contamination were intended, Baumgardner could have suggested a test be run upon a sample that is not only radiocarbon-dead, but outright carbon-devoid. Quartz would be an ideal choice, both because its structure is silicon dioxide, containing no carbon whatsoever, and because silicon has many properties which are similar to carbon, allowing a sample to be better prepared for the AMS. If, using quartz, some trace amount of 14C were detected, we would know the results were due to sample contamination from some outside source. This would have been a good control for Baumgardner’s experiments, and would have made his work a genuine bit of science instead of a deliberately planned foregone conclusion.

One thing bears noting: The RATE team does point out a legitimate anomaly in 14C dating techniques. Trace amounts of radiocarbon simply shouldn’t be present in coal or diamond. So how did it get there? The lack of information to be found on this matter seems to indicate that scientists have yet to adequately address this problem. But a likely answer, which is consistent with everything we already know, is that it’s simply a matter of trace amounts being detectable in anything, if the instruments are sensitive enough. Carbon 12 makes up 98.9% of all carbon, with Carbon-13 making up 1.1% The percentage taken up by Carbon-14 is already a trace element at today’s levels, only a million-millionth, or 10-8 %! The fact that we can do any radiometric dating at all with such tiny amounts is remarkable. The sources for the trace amounts of 14C could come from literally anywhere – the sweat of a coal miner’s brow, the oils secreted by fingers handling the sample without gloves, or even the CO2 exhaled by a nearby scientist. But even with painstaking precautions, the 14C seems to find a way into the AMS every time. It would be worthwhile to find out why.

Perhaps the most important lesson the RATE team has taught us, is that we oughtn’t be quite so smug. Even a blind squirrel may find a nut, and a legitimate criticism can come from any source, no matter how misguided. If nothing else, creationists force us to go over the data one more time, and that’s always a good thing.

(1) This was due, of course, to the reservoir effect, in which mollusks or certain benthics get the carbon in their shells from radiocarbon-dead source material, such as dissolved limestone.

2 Comments:

At 1:48 PM, Anonymous Anonymous said...

You give the RATE team a bit too much credit on pointing out discrepancies in radiocarbon; most of these effects are known and understood. I recommend these critiques of the RATE claims by the ASA: http://www.asa3.org/ASA/education/origins/rate.htm

 
At 3:45 PM, Blogger SaganJr said...

Thank you for the excellent link. And yes, I wasn't aware how well these trace background-amounts were known already. I'd revise my statement if I were re-writing this today. But my original critique -- that a quartz crystal should have been tested as a control -- is still quite valid.

 

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