More Faulty Creation Science from The Insitutute for Creation Research
More Faulty Creation
Science from The Insitutute for Creation Research
Page Created
November 13, 2000
Updated February 6, 2003
J.G. Meert
he Institute for Creation Research is promoting a
new research focus aimed at discrediting radiometric dating methods. The group in charge of this recent effort
chose the acronym R.A.T.E. (Radioisotopes and the Age of The Earth). Their
'research' efforts are aimed at discrediting modern geochronologic methods (using flawed
experiments as discussed below) and replacing it with some form of miraculous isotopic
behavior. So what exactly is the RATE group attempting and who is in charge of the
research effort?
Point #1: Although the RATE group has undertaken a massive fund-raising effort amongst ye-creationists, none of its members has experience or training in experimental geochronology. Two members, Austin and Snelling have written a number of articles in creationist magazines, but neither has published articles using radiometric dating in the mainstream literaturea. Their IMPACT series articles, IMP326, IMP319, IMP309, IMP307, IMP301, IMP224 along with several 'technical articles' (eg. St Helen's Dacite) attempt to discredit radiometric dating based on 'anomalous' results. The problem is that the anomalies were all generated via experimental flaws on the part of the investigators or simply misinterpreting technical articles from peer-reviewed scientific literature. Refutations and discussions of these flaws abound (see, for example: Austin Grand Canyon study) and will not be repeated here. The main point to be made is that accurate radiometric dating requires certain analytical care. It's easy enough to collect a rock and send a check to Geochron Labs and have them produce a 'date' (which is exactly what Austin does). It is quite another thing to collect the proper sample, conduct the mineral separations (checking for possible inclusions and overgrowths), do the column chemistry, prepare the bombs and analyze the results. More on this in a moment--because the argument that no member of the RATE group has proper geologic training to conduct the studies is germane to several of their proposals. In fact, far from being an ad-hominem attack, it demonstrates a basic level of misunderstanding on the part of the RATE group that is sure to produce additional bogus science.
The RATE group proposes the following set of experiments to 'test' the vailidty of modern geochronologic methods. Note that the Group asks for money to conduct the research, but is vague on the specifics. Such a request for funding in the scientific world would be rejected out-of-hand. However, since the foregone conclusions form an integral part of the funding request, I suppose they will reach their goal!! The other problem with the proposed work is that the Group ignores a wealth of modern research and present flawed experiments for other parts. I will address each of their proposals below:
"Increase evidence for discordance among isotopic dating methods using isochrons for mineral components of flood related rocks. Based on the consistency of the discordance from this specimen (a flood gabbro) and others, infer the processes which led to the distribution of isotopes" (taken from ICR 314, see link above)"
I want to call your attention to several issues regarding their proposal. The first is that the RATE Group has pre-determined that the sample will be discordant (or, in this case will not produce an isochron). Therefore, the RATE Group has already reached their conclusion! Why even do the experiment? No doubt it will produce an imprecise alignment of minerals and whole rocks because of the sample they chose1. Why did they choose a flood gabbro? Although, I cannot be sure about the methods to be used by the RATE Group, I assume that the isochron method of choice will be either K-Ar or the Rb-Sr method simply because they are most affordable. There are a number of ways to produce bad data in geochronology1,2. The easiest is to apply the wrong method to the wrong rocks. A gabbro is not the ideal specimen for Rb-Sr/K-Ar dating (especially if it is a very young gabbro) for two reasons. Both methods rely on the presence of abundant K-bearing minerals (Rb substitutes for K in many minerals due to their similar ionic radii) and gabbros do not typically contain an abundance of K-bearing minerals1. The methods are also not particularly useful for young mafic rocks due to the lengthy half-life of 40K and 87Rb (see table here). That is not to say that these methods CANNOT be applied to mafic rocks, but there are better methods based on the mineralogies present in gabbroic and other mafic rocks (U-Pb on baddelyite for example).
The second issue has to do with the sample selection itself. The proposal states a conclusion without providing support. The RATE group claims this is a 'flood-related' rock! They provide no evidence for the flood nor has any creationist been willing to specify exactly what sequence of rocks represents the flood on earth. Furthermore, a gabbro is an intrusive igneous rock and therefore in order to be identified as 'flood-related', it must intrude sedimentary (or other) strata that are considered to be part of the flood. Of course, since these strata have never been formally recognized the argument is specious.
Bottom Line: The RATE group will produce discordant results because they have guaranteed discordance in their proposal. This does not represent research, it represents a planned confirmation of a faulty hypothesis and can not be called science in any sense of the word.
AN UPDATE (Feb 2001). A friend kindly faxed me the actual proposal in the RATE book. Austin's discussion of isochrons is rather naive, but he is seeking love donations to 'prove' something that is already known. Here is a point-by-point discussion of his proposal.
Point 1: Introduction to Isochron Dating: Whole-Rock Isochrons
Austin discusses the whole-rock isochron dating method. His discussion is accurate in that this method requires a co-genetic suite of rocks. The method was widely used in the past (particularly using the Rb-Sr method), but is not as frequent in the literature today because of the difficulty in finding truly co-genetic rocks. He then goes on to discuss the Cardenas Lava 'problem' which he created by misuse of data. Chris Stassen provides a lovely critique of this 'research'.
Point 2: Mineral Isochron Dating
Austin correctly notes that mineral isochron dating is a better approach because one can study a mineral suite in a single rock. If no metamorphism has occurred in the rocks, then the minerals can be assumed to be derived from the same isotopic reservoir. Furthermore, different minerals have different affinities for isotopes of Rb and K so that they will 'evolve' along different paths. In simple terms, minerals with more Rb will produce more daughter product over time than will a mineral with less Rb. When the parent/daughter ratios are plotted on a isochron diagram, they should form a linear array with an intercept that gives the level of daughter product already in the system and a slope which can be used to calculate the age of the rock. Austin, then incorrectly claims that this method is not used because it requires skill in the laboratory (column chemistry and separation). It is certainly tedious and it does require training (Austin has never done this himself), but Austin's claim that it is not used is simply false. Typically, the analyses are done using both whole rock and mineral isochrons and references to this type of dating are easy to find with a literature search. In fact, the database from eastern Gondwana (1050 age determinations) shows that about 50% of the Rb-Sr ages are whole rock and about 50% are whole-rock mineral isochrons.
Part 3-Applications
This is where Austin asks for money and sketches his plan. The 'proposal' itself covers 2.5 pages and asks for $50,000. One might wonder why Austin does not submit this proposal to the National Science Foundation. I can tell you why. Such a hastily sketched out plan, with no focus (such as his) would be rejected by any rational funding agency. On page 571 Austin makes the following statement:
"Ultimately, the mineral isochron method can be used as a partial test of the assumption of constant decay of radioisotopes in rocks. If the homogenization and closed system are assumed, then discordant mineral isochrons could argue for different decay rates between the various parent isotopes"
Of course, different isotopes have different decay rates and Austin is arguing that if his samples show different ages using K-Ar/Rb-Sr and Sm-Nd, then this would imply different decay rates for a-emitting (Sm) versus b-emitting particles (K, Rb). If all mineral isochrons showed a similar discordance, then Austin might indeed have a case. The problem is that there are already more concordant dates using various isotopes in the literature than Austin can possibly generate in this proposal. Austin develops this mystery by citing his own work on a Precambrian sill that gave older Pb-Pb ages than Rb-Sr ages. What Austin does not mention is that this Precambrian sill does not meet the criteria he outlined above. The Pb-Pb system is more resistant to thermal effects than is the Rb-Sr system and this region has been affected by several low-grade thermal events. Therefore, a more troubling result would be to find concordant Rb-Sr and Pb-Pb isochrons since this would negate the observed metamorphism in the region. Furthermore, I find the idea somewhat amusing since Austin has 'published' evidence for these metamorphic events himself. Of course, he failed to recognize these in his paper because he ignored the tectonic history of the region. Austin proposes to collect more data from this sill and he will no doubt get discordance (I guarantee it!). The problem is that the discordance will reflect metamorphism rather than some fundamental change in decay constants. His second sample is from the Beartooth Mountains in Wyoming. This is an amphibolite-grade metamorphic rock, but Austin gives no further details other than a reference to a 1982 Rb-Sr isochron age of 2790 Ma (Wooden et al., 1982). This age 'dates' the metamorphism of the rock. Austin asks the question:
"A mineral isochron analysis should be performed to test for concordance of the different radioisotopic clocks. Will the various mineral isochron ages agree with the Rb-Sr whole rock isochron?"
The answer is a resounding "NO!", but not for the reasons Austin would have you believe. As noted by Mueller et al. (1996, Precam Res., v. 78):
"The Beartooth-Bighorn magmatic zone (BBMZ) and the Montana metasedimentary province (MMP) are two major subprovinces of the Archean Wyoming Province. In the northwestern Beartooth Mountains, these subprovinces are separated by a structurally, lithologically and metamorphically complex assemblage of lithotectonic units that include: (1) a strongly deformed complex of trondhjemitic gneiss and interlayered amphibolites; and (2) an amphibolite facies mafic unit that occurs in a nappe that structurally overlies the gneiss complex. Zircons from a trondhjemitic blastomylonite in the gneiss complex yield concordant U-Pb ages of 3.5 Ga, establishing it as the oldest rock yet documented in the Wyoming province. Two younger events are also recorded by zircons in this rock: (1) an apparently protracted period of high-grade metamorphism and/or intrusion of additional magmas at approximately 3.25 Ga; and (2) growth of hydrothermal zircon at approximately 2.55 Ga, apparently associated with ductile deformation.
Depending on what minerals and what other isotopic systems Austin chooses for dating, he should get ages ranging between 2550 and 3500 Ma. The discordance is predicted because of the polyphase metamorphism in the area. Incidentally, one does not simply 'pick' a few minerals from such a location without noting the tectonic relationships, alteration observed and in the case of zircons, detailing the internal structure of the minerals using cathodoluminescence. Austin does include budgeting for chemical analyses of the minerals, but does not include cathodoluminscence which is imperative for detailing the zircon overgrowth due to subsequent events. Without that analysis, there is a definite risk of obtaining a 'mixed' age from the zircons that would have no significance.
Dating Chert and Dolomite Redwall Limestone
For the life of me, I have no idea why Austin is choosing to conduct such an investigation. He notes that the rocks have been altered and dating of sedimentary rocks using Rb-Sr is fraught with difficulty as is determining ages of sedimentary rocks via other methods. It CAN be done, but requires a lot of time and detailed mineralogical analyses. Austin claims an Rb-Sr isochron can be easily constructed. This is also true, but what is the significance of such an isochron? Once again, I predict that since Austin has no experience in dating these rocks, he will assure himself of discordant results. The problem is that such an effort will not add anything significant to our knowledge.
Dating of Lava Dams
Austin then wants to date olivine using K-Ar. Although olivine may entrap a small amount of excess argon, the structure of the mineral makes it useless for conventional K-Ar dating. It is no mystery that minerals such as olivine and pyroxene contain excess argon and for this reason, the minerals are avoided by conventional scientists. When attempting to overthrow the K-Ar method in this fashion, Austin should also use 40Ar/39Ar methods as these stepwise dating methods tend to reveal the presence of excess argon. For example:
This rock (from Madagascar) would give a K-Ar age of 1997 +/- 4 Ma. The problem is that it contains excess argon (note the extremely old ages at either end of the 'saddle'. Ar-Ar analyses clearly shows the presence of excess argon and the presence of excess argon makes dating of this sample difficult. Austin KNOWS that olivine is not suitable for precision K-Ar dating and he KNOWS that Ar-Ar dating would reveal the excess argon, but he will only perform K-Ar because it is guaranteed to give a spurious result. There is no science in this proposal and the results are guaranteed before conducting the experiments. I argue that $50,000 could be more wisely spent feeding hungry children in third world countries rather than perpetrating scientific fraud!
Since Gentry first published his observations on Po-haloes in micas, the radiohalo argument has become a long-lasting favorite among ye-creationists. The problem is that a number of articles explaining these 'anomalies' have been made and ignored by ye-creationists There are some very good on-line sources with references; for example visit Creation's tiny violences or Po-halo discussions. Here is the proposal by the RATE Group:
"Resolve the question if polonium haloes are special evidence for created rock only or could they also occur in flood rocks. This effort may also allow inferences about the process of radioisotope decay and halo formation"
Note that here too, the RATE Group has presented a false dichotomy. Polonium haloes may indicate that NEITHER of their proposals are correct! In fact, we see the RATE group again referring to flood rocks without specifying what rocks constitute flood strata. I keep harping on this point because no creationist will allow themselves to be pinned down on how flood strata are indentified and how to correlate flood strata. Furthermore, many of the Po-haloes are found in igneous intrusive rocks and therefore they must also intrude flood strata.
Bottom Line: The presence of Po-haloes in micas has been explained in the scientific literature. It is 'No tiny mystery' nor is it troubling to the concept of constant radioactive decay.
The proposal:
"Fission track estimates of nuclear decay are thought to be absolute following rock formation and do not inherit prior evidence of decay. It is important to know if decay rates were accelerated during the flood"
Case #3 where a flood is assumed without first supplying evidence for the flood and also no description of how flood strata are identified. Furthermore, fission-track dating is a difficult procedure and requires specialized training and experience. None of the RATE Group has any experience with fission track dating as is demonstrated by their lack of understanding of the process. This naiveté is obvious from their description of fission-track dating above. Fission-track1 estimates are not 'absolute' following rock formation, indeed one of the major uses of fission-track dating is determining the thermal history of rocks following their formation since the tracks are easily annealed at low temperatures3,4. The sample the RATE Group intends to use is a tuff bed in the Mauv Formation of the Grand Canyon. This is an interesting choice because conventional science indicates that there has been uplift (and hence thermal changes) of the region for the past 5-10 million years. Therefore, fission-track analyses most likely would not reveal the absolute age of this rock or even reflect processes at the time of its formation!
Bottom Line: Flawed experimental premise that fission-tracks are not affected by external thermal processes. In fact, the principle utility of fission-track dating is detailing thermal and uplift histories of regions rather than absolute dating of rocks.
The premise of the RATE work is this:
"Acquisition of data on which to base a claim that the amount of helium in rocks today should not be so high if it was produced by nuclear decay over millions of years. If helium was produced within the most recent thousands of years, it would be expected to still remain in the rocks as observed"
Mumbo-jumbo. The claim here appears to be that there is too much helium in the rocks today. The RATE Group does not provide an explanation of what is too much. It states rather matter-of-factly that it is too high. The rate of helium diffusion from minerals is not a simple linear process1,5,6. Once again, the RATE Group begins with a false premise that it intends to prove by misinterpretation of the data and an incomplete reading of the literature. Remember: Misinterpreting Science is not the same thing as disproving science. Humphreys takes issue with me on this at http://www.answersingenesis.org/docs2002/1030meert.asp
Humphreys claims that helium is not retained for any great time in zircons. He proposes that zircons close and 'then re-open" to helium diffusion shortly after their closure temperature. Dodson describes the concept of closure temperature as follows:
" It is assumed that, while the system is near to the temperature of crystallization, the daughter nuclide diffuses out as fast as it is produced by radioactive decay. As the system cools, it enters a transitional temperature within which some of the daughter product accumulates in the mineral and some is lost. Eventually, at temperatures near ambient, the losses are negligible, and the daughter product accumulates without any loss whatsoever.....Closure temperature can be given a precise definition namely the temperature of the system at the time given by its apparent age"
Humphreys work describes a number Q which he states is the 're-opening'. This re-opening is defined as marking a point where helium loss is balanced by helium production resulting in a steady state level of helium within the zircon. Unfortunately, Humphreys does not provide the critical analysis for defining what Q really is (he refers to equation 16, but did not bother to post it). Therefore, it is difficult to analyze exactly what Humphreys is talking about without providing the relevant equations. There certainly is a point in the cooling history of zircons where loss=gain, and this may even occur at temperatures below the 'closure temperature', but Humphreys assertion that the zircons would maintain this steady-state situation is not grounded in good science.
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