More on radioactive dating problems
A further response to Reasonable Faith Adelaide
Published: 20 June 2015 (GMT+10)
We previously reported an event organized by the Adelaide, Australia, Chapter of Reasonable Faith where Dr Justin Payne, a lecturer within the School of Earth and Environmental Sciences at the University of Adelaide, sought to ‘disprove’ objections to long-age radiometric dating. At their request, physicist Dr Jim Mason, of CMI Canada, reviewed the material from the meeting and his response was published on 2 April 2015 (see Response to Geochronology: Understanding the Uncertainties, a presentation by Dr Justin Payne). Kevin Rogers submitted a comment to that article (reproduced below, edited to focus on substantive issues), to which Dr Jim Mason replies.
Radioactive Dating Methods
I am Kevin Rogers and am the director of Reasonable Faith Adelaide. Last year we held a number of meetings on the young/old earth issue and gave YECs numerous opportunities to speak. Andrew Kulikovsky spoke on one occasion and John Hartnett spoke on 2 occasions. However, we are a house divided. About half those who are on the committee are YECs and the others doubt the YEC position to various degrees.
Jim raised some interesting points but I don’t believe that he addressed the central points that Justin raised.
Jim stated that “uranium is preferentially encased in these [zircon] crystals while lead is preferentially excluded” but did not fully explain the significance of this. It can be experimentally confirmed that molten Zircon rejects lead. This is highly significant, as it means that the initial conditions are known to a high level of confidence.
The other point that Justin made was that the dating for Uranium/Lead can be derived from 3 sources: U238 decay, U235 decay and the lead isotope ratio. These 3 methods can be checked against each other, especially using the Concordia line/diagram. Jim Mason made no reference to the Concordia line and I could not find any reference to the Concordia line on any articles on the CMI website, even though it is well known (e.g. see Wikipedia article on “Uranium-lead dating”).
Jim raised the issue of Helium concentrations in Zircon. This is interesting, but it was not discussed at the meeting and I do not know how Justin would respond.
Justin is not a Christian but does not particularly seem anti-Christian either. He is just a scientist who is doing his job and he doesn’t seem to have any particular axe to grind. He was invited to our meeting as a guest speaker solely for his expertise on radioactive dating. Justin has practical experience in U-Pb dating. He often goes on field trials dating rocks in various regions of the Australian outback. He has equipment at the University of Adelaide and does the dating analysis himself. Thus he has the knowledge of an experienced practitioner and is not just an armchair theoretician.
Director, Reasonable Faith Adelaide
Dr Jim Mason replies:
It seems to me that your comment contains the following issues:
- the mineralogy of lead in zircon crystals
- the Concordia technique,
- the credentials and competence of Dr Payne,
Taking each of these points in turn …
1. Mineralogy of zircon crystal formation
My comment about the inclusion of uranium and exclusion of lead during the formation of zircon crystals was just a repeat of an assertion made by Dr Payne. Not being a chemist, a mineralogist or a metallurgist, I have no reason to dispute this claim and, hence, did not include any further discussion. I would note, however, that the efficiency of the exclusion was not mentioned (i.e. is 100% of any lead excluded from the crystal or, perhaps, less than 100%). Nor was there discussion about how well the experimental conditions that have been mentioned would have represented the situation within crystallizing magmas. Uniformitarians assume magmas crystallized slowly over millions of years under conditions of thermodynamic equilibrium. However, the biblical scenario suggests magmas crystallized quickly, and anticipates non-equilibrium conditions, and this would affect the way lead would have been incorporated in the zircon crystals. Geologists now recognize that granites formed very rapidly, which is consistent with the biblical scenario. As I pointed out in the article, when the isotopic abundances are being measured very near time zero and the half-life of the radioactive parent is very long, then even a small amount of radiogenic daughter being present at time zero will result in a large erroneous ‘age’ calculation.
Furthermore, a recent article “Metallic lead nanospheres discovered in ancient zircons”1 says (in the introductory “Significance” section): “The heterogeneous distribution of Pb can, however, affect isotopic measurement by microbeam techniques, leading to spurious age estimates.” This raises significant questions for the technique and casts doubt over its robustness.
2. Concordia line/diagram technique
I did not discuss this technique because it seems a pretty straightforward combination of various parent-daughter relationships. The Wikipedia article that you reference would seem to confirm this. The technique does have the added advantage that if the ‘ages’ from both the 238U and 235U chains agree with each other, it adds support to the hypothesis that both chains have experienced the same effects during the formation and lifetime of the crystal.
A colleague, Dr Tas Walker, advises that, “the Concordia technique arose from the fact that the two U decay series should give the same ‘age’ but almost always they didn’t—i.e. they were discordant. So the question is, ‘Why?’ The claim is that if a rock undergoes a metamorphic process then some of the U or Pb from the zircon would be lost, which means the ages would no longer be concordant. So, where the top part of the line through the zircons intersects the Concordia curve is said to be the ‘age’ of the zircon. Where the bottom part intersects the Concordia curve is said to be the ‘age’ of the metamorphic event. However, this only works if there is one metamorphic event. If there is more than one metamorphic event, and for almost every situation there would be many, the intersection of the line with the Concordia is meaningless.”
I note that in the Wikipedia article that you identify,2 the opening sentence refers to “precisions in the 0.1–1 percent range” (my emphasis) for this technique, confirming the point I made in my article that the uncertainties quoted for radiometric ages (and indeed all other quantities) are a measure of precision (or repeatability) of the measurement technique and not accuracy of the age. I also note that the last sentence in the lead-in section identifies someone as “having used it [this technique] to obtain one of the earliest accurate estimates of the age of the Earth.” However, I would question how it is known that the age estimate is accurate. To make such a claim, one would need to know independently and unarguably just what the age of the Earth actually is. I submit that there is no such independently and unarguably known age—unless one is prepared to accept the age that is derived from the Bible, that was provided to us by God, an eyewitness, and some reliable scribes.
In any event, a discussion of the Concordia technique would have been peripheral to the point that I was trying to make. That is, that while U-Pb dating gives an ‘age’ for certain zircon crystals (the same type of crystals used by Dr Payne) of 1.5 billion years, using another product (alpha particles) from the same radioactive decay chain (238U) and a property of the crystal that is unconnected to radioactive decay (diffusivity) gives an age for the zircon crystals of just 6,000 years. Assuming that the measurements in both cases were appropriately done—and I see no reason to suspect otherwise since they were both done by independent, third-party labs—and that the uncertainties were appropriately estimated—and, again, I see no reason to suspect otherwise since these would be dependent on the equipment and procedures used by the labs—these two results cannot be considered to be the same, or an aberration of the equipment and/or technique. So at least one of them—and perhaps both—is incorrect.
It is not possible to choose between them based on the measurements themselves. However, as I noted, and listed, in the article there is much evidence from a variety of different sources and scientific disciplines that indicates the Earth cannot be billions of years old and/or that it is just a few thousand years old. Consequently, it seems reasonable to conclude that the 6,000 year determination is correct—or, at least, closer to the truth than the 1.5 billion year one.
That, of course, leads to the conclusion that at some point in the past there was a period of accelerated nuclear decay.
Of course, I said all this in the article, so I apologize for repeating myself. I have done this in order to relate back to the Concordia technique.
The graphs of 238U abundance that I presented in the article for these two situations illustrate that the isotopic abundances in the present (indeed at any point after the accelerated decay period) would be identical. Of course, the isotopic abundances of decay products, especially lead, would follow a 1 – 238U curve. As with the 238U, the abundance of lead in the present for the two situations would be identical.
Now to establish an ‘age’, uniformitarians effectively use the ratio of Pb to U to define a point on the uniformitarian curve, which, in turn determines the time since time zero based on the uniformitarian assumptions. Each point on the uniformitarian curve has an identical point on the accelerated decay curve. At this point, the Pb-U ratio is identical to that for the uniformitarian curve. However, the translation of this into an elapsed time from time zero is different because of the different assumptions used to effect the translation.
In the case of the Concordia technique, which uses two U-Pb decay chains, since the two decay chains start and end with the same elements and both are dominated by alpha decays, it is reasonable to assume that both would be affected in the same relative manner by any mechanism that accelerated the decay rate. Consequently, for any particular crystal, we would see the same result on the diagram.
Thus, it seems to me, that the Concordia technique does not possess any additional ‘strength’ with which to claim accuracy or improved robustness over any of the other radiometric dating techniques.
3. Dr Payne’s credentials/competence
I certainly did not intend to question Dr Payne’s credentials or competence. Just as I would assume that he would not question the credentials or competence of Dr Snelling, whose work he criticized in the presentation, nor any of the other scientists who did the RATE research. Dr Payne did make that one factual error about fission tracks that I felt should be corrected to avoid possibly confusing others.
Nor did I assume that he had a particular axe to grind. However, he undoubtedly has a set of presuppositions and assumptions that he brings to his analysis of data in his U-Pb dating. While three of these assumptions were explicitly dealt with in his talk and my response, there are others of which he may not even be consciously aware and that have, perhaps, a more profound impact on his analysis of data and his conclusions.
One of these is the philosophy of naturalism, the impact of which I discussed in my article. Another is the assumption of uniformitarianism—in particular the assumption of uniformity of rate across time and space. Although it can be dangerous to use Wikipedia as a reference source (see, for example, the National Post article “The story of Jar’Edo Wens, the longest-running Wikipedia hoax”,3 which documents a just-recently-detected hoax, embedded in Wikipedia, that went undetected for nine years and even made it from Wikipedia into non-Wikipedia sources), the Wikipedia article on uniformitarianism4 states:
“Uniformity of rate (or gradualism) is what most people (including geologists) think of when they hear the word ‘uniformitarianism’, confusing this hypothesis with the entire definition. As late as 1990, Lemon, in his textbook of stratigraphy, affirmed that ‘The uniformitarian view of earth history held that all geologic processes proceed continuously and at a very slow pace’. Gould explained Hutton’s view of uniformity of rate; mountain ranges or grand canyons are built by accumulation of nearly insensible changes added up through vast time. Some major events such as floods, earthquakes, and eruptions, do occur. But these catastrophes are strictly local. They neither occurred in the past, nor shall happen in the future, at any greater frequency or extent than they display at present. In particular, the whole earth is never convulsed at once.” (emphasis added)
So, in the study of geology (Dr Payne’s discipline), it is assumed a priori, that the global Flood described in the Bible never happened. Consequently, any explanation of the evidence that uses a global flood is automatically ruled out—no matter how well the explanation actually fits the data. I think that this assumption was on display in Dr Payne’s dismissal of the RATE explanations that involved the Flood and in his closing slide that noted “not a Flood ‘Geology’ scenario”. In fact, as a secular geologist, he is not allowed to entertain the possibility of a global flood.
These two philosophical presuppositions/assumptions—naturalism and uniformitarianism—which have been unnecessarily imposed on the scientific establishment are, it seems to me, restrictive and exclusionary. That is, they arbitrarily restrict the solution space and, thereby, exclude certain solutions/explanations and, as a result, often force “unsubstantiated just-so stories” (as Lewontin put it) that seem to get accepted without question. It is analogous to allowing only right-hand turns during a trip. Such exclusion is not because left-hand turns do not exist, because they do and, in fact, may provide the shortest—or even the only—route to the destination. Rather they are excluded simply because one doesn’t like them—they are ‘sinister’ after all.
This, it seems to me, is what has happened in the scientific culture. Explanations have been limited to natural processes, even though we know, as I pointed out in the article, natural process cannot provide the correct explanation for the origin of the Boeing 747. This has not been required by the data but rather is imposed on the data because people don’t like the alternative. Similarly, in geology, explanations have been limited by uniformitarianism, although now with the occasional introduction of a spatially and temporally isolated catastrophe. However, consideration of a global catastrophe is explicitly excluded—notwithstanding the fact that it might provide a comprehensive and coherent explanation of the observed data. Certainly Nicolas Steno, one of the pioneers of geology, thought so. Again, this restriction is not required by the data but is imposed a priori on the interpretation of the data because people don’t like the implications of a global flood.
In your response you also said, “However, we are a house divided. About half those who are on the committee are YECs and the others doubt the YEC position to various degrees.” Can I suggest that these differences arise because people have different starting points as I have just discussed. There are two basic starting points:
- The Bible reveals to us the true history of our planet: God created this world, which was very good without death, disease or suffering, in six days about six thousand years ago by supernatural processes. This world has subsequently 1) been spoiled by the first man’s sin, which introduced death, disease and suffering, 2) been destroyed and remade by the global Flood about 4,500 years ago.
- Naturalism, by which the origin and development of this planet is to be explained entirely by natural laws and processes observable in the present. This leads to the conclusion that the earth must be billions of years old, God is not necessary to explain the world, and the events of the Bible, particularly Genesis chapters 1–11 did not happen as described.
Many people think, and this is the important point, that they can prove which worldview is correct simply by looking at the scientific evidence, such as radiometric dating. However, it is not quite that straightforward.
Data (evidence) do not ‘speak for themselves’. They need to be interpreted and this interpretation needs an interpretive framework that, in turn, will depend on presuppositions. Two of these interpretative frameworks are identified above along with their presuppositions.
However, people, in general, have not been taught how to distinguish between scientific evidence (i.e. that which is measured and verified using the scientific method of repeated experimentation) and the interpretation of the evidence. In the case of radiometric dating, the evidence consists of the relative isotopic abundances in a sample, measured today, using devices such as Accelerator Mass Spectrometers. One’s worldview would not be expected to influence the measurements so obtained. However, the interpretation of these measurements, i.e. the assignment of an ‘age’ to the sample, depends on one’s assumptions/presuppositions about the past.
In the case of palaeontology, say, the evidence is the fossil and the rock layer in which the fossil was found. The assignment of an age to the fossil is an interpretation based on the rock layer in which it was found, which, in turn, is based on the presuppositions of uniformitarian geology and naturalism. Yet, when people hear the newscast about the latest find of a fossil said, for example, to be some 200 million years old, how many of them understand that the asserted age is not a scientific fact but just speculation?
While evidence can’t prove a worldview correct, it can, in my opinion, be used to assess the veracity of a worldview or, if you like, the relative veracity of two worldviews, in particular the two identified above. As I noted in the original article, this is akin to what a jury does in a criminal trial, especially when there was no eyewitness to the crime. The jury looks at the evidence and assesses which of the two interpretations of the evidence (the one given by the prosecution or the one given by the defence) provides the most comprehensive and coherent explanation of the evidence and, therefore which underlying presupposition is correct, i.e. whether the defendant is guilty or innocent.
When one looks at the totality of evidence—not the interpretation, but the evidence—across all the scientific disciplines, it seems to me that the interpretation based on the naturalistic/evolutionary worldview provides a very unsatisfactory explanation, requiring many hypothetical and unverifiable entities and processes, some of which actually contradict known laws of physics and chemistry, as well as numerous ad hoc, disjointed just-so stories. On the other hand, the explanation based on a biblical worldview, is comprehensive, coherent and robust.
For example, the scientific evidence from chemistry, genetics and biology does not support, and in many cases actually contradicts, the naturalistic/evolutionary worldview whereas the evidence from these disciplines is what would be expected from the biblical worldview. Evidence supporting the naturalistic/evolutionary worldview is generally absent from palaeontology and the associated explanation of what evidence there is requires many just-so stories, which, it seems, continually need to be revised with almost every new fossil find. On the other hand the paleontological evidence is quite consistent with a biblical worldview. Similarly, the scientific evidence from geology and cosmology does not fit well within the naturalistic/evolutionary worldview explanation but requires many just-so so stories and numerous hypothetical entities/processes. But this evidence is consistent with the biblical worldview without the need to resort to such rescue devices.
When this assessment of the scientific evidence, which attests to the veracity of the Old Testament, and Genesis 1–11 in particular, as accurate history, is combined with an archeological and historical assessment of the New Testament such as described in The Case for Christ by Lee Strobel, Evidence that Demands a Verdict by Josh McDowell and Cold Case Christianity by J. Warner Wallace, all of which attest to the veracity of the Gospel accounts as accurate history, then it seems to me, there is clear and compelling evidence that the biblical worldview is correct.
And unlike the decision about which clothes to wear or which car to buy, the decision about which worldview is correct has eternal significance.
This exercise has been a good opportunity to think about what one is going to take as one’s starting point and to what one will ascribe ultimate authority (God and His Word or man and his ideas). I appreciate the opportunity to have been able to participate in that.
References and notes
- Kusiak, M.A., Dunkley, D.J., Wirth, R., Whitehouse, M.J., Wilde, S.A., and Marquardt, K., Metallic lead nanospheres discovered in ancient zircons, PNAS 112(16): 4958–4963, 21 April 2015; doi: 10.1073/pnas.1415264112; Abstract: pnas.org. Return to text.
- Uranium-lead dating, en.wikipedia.org. Return to text.
- Dewey, C., The story of Jar’Edo Wens, the longest-running Wikipedia hoax, and why it’s so hard to police the free encyclopedia, Washington Post, 16 April 2015; news.nationalpost.com. Return to text.
- Uniformitarianism, en.wikipedia.org. Return to text.