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Woodmorappe's Subjective Creationism and Not So Subjective Radiometric Dating
Dr. Kevin R. Henke

The following material may be freely copied and distributed as long as the author is properly acknowledged
and the material is not altered, edited or sold.


YECs would like nothing better than for the public to mislabel radiometric dating as a subjective, irrational, arbitrary, dogmatic, closed-minded and frail 'religion', in much the same way that scientists view young-Earth creationism.  To achieve this libelous goal, Woodmorappe (1999, p. 8 and elsewhere) attempts to portray radiometric dating as being 'subjective' by quoting statements from the radiometric literature.  As an example, Woodmorappe (1999, p. 8) quotes the following statements from Harrison (1990, p. 227):

'Subjective influences on a scientist are clearly exposed when evaluating an experiment design and deciding which parameters are constant and which are variable.  Because of the extreme challenge of geological time, geologists are often confronted with more ambiguous scenarios than the norm, amplifying the contribution of personal taste or philosophy. ... It can be surprising how different are the approaches of geochronologists to essentially identical problems, and not surprising that many misunderstandings arise as a result.'

Woodmorappe (1999, p. 8) fails to mention that Harrison's (1990) article emphasizes the use of the 40Ar-39Ar method on feldspars.  The above quotations may or may not apply to other minerals and radiometric methods.  Nevertheless, Harrison (1990) sees widespread strengths in the 40Ar-39Ar method, which Woodmorappe (1999) repeatedly ignores.  Harrison (1990, p. 227) even argues that investigators would not have the tendency to be overcritical of the 40Ar-39Ar method if they would simply avoid faulty assumptions and not try to 'find global consequences in the failure of particular samples to yield straightforward results'.  In particular, Harrison (1990, p. 219) states:

'In matters related to excess Ar, anomalous age spectrum shapes, slow cooling effects and radiogenic 40Ar (40Ar*) loss, internally CONSISTENT, TESTABLE models are AVAILABLE which appear to WELL describe end-member phenomena.  Simultaneously, however, criticisms have appeared which challenge the very basis of the method in providing chronological data, let alone thermal histories.   The resolution appears not to lie in differing experimental approaches, but rather in the PERSISTENCE OF ARGON FOLKLORE AND A TENDENCY FOR SOME TO ENDOW A SIGNIFICANCE TO THEIR RESULTS BEYOND THE SCOPE OF THE SAMPLING.' [my emphasis]

Harrison's warnings about extrapolating unusual results to other samples and believing in 'argon folklore' are particularly relevant to Woodmorappe's common tendency to comb the literature to find unusual and difficult samples and then misapplying them to all other situations!  In particular, Woodmorappe (1999, p. 8) cites portions of Harrison's (1990) article on the application of the Ar-Ar method to feldspars, somehow claims that these statements apply to radiometric methods in general, and then ignores Harrison's (1990) clear condemnation of such misapplications and inappropriate extrapolations. 

Woodmorappe (1999, p. 8) also quotes Baksi (1990, p. 985) to argue that radiometric dating methods are 'subjective':

'Subjective and, in many instances, incorrect use of radiometric data has become endemic in the earth science literature... [rest of paragraph omitted by Woodmorappe, no ellipses used]. Mathematical analysis of imperfect and in, many cases, highly subjective data sets leads [sic] to dubious conclusions.'

Rather than denouncing the current state of radiometric dating methods or even the dates themselves, Baksi (1990) is criticizing the subjective USE of radiometric data by some researchers to argue that mass extinctions occur in cycles of 26 to 33 million years.  In his abstract, Baksi (1990, p. 983) further states:

'Periodicity hypotheses for various global events over the past ~250 m.y. are reevaluated following rigorous inspection of the radiometric data base utilized therein.  I suggest that these periodicities of ~26 to ~33 m.y. result from SUBJECTIVE USE of radiometric data in the literature.'  [my emphasis]

Baksi's (1990, p. 985-986) statements, which were partially quoted by Woodmorappe (1999, p. 8), are listed below in greater context:

'Subjective and, in many instances, incorrect use of radiometric data has become endemic in the earth science literature.  Dalrymple and Lanphere (1969) summarized the problems in putting the K-Ar clock to work.

'Mathematical analysis of imperfect and in, many cases, highly subjective data sets leads [sic] to dubious conclusions.  Further search for periodicity in global events should be postponed until high-quality radiometric data become available for the various events under consideration.  Recent advances in analytical techniques make the acquisition of the required data sets RELATIVELY STRAIGHTFORWARD. Thus, Tucker (1989) in his U-Pb study of zircons from ash beds, using techniques by Krogh (1982), obtained ages with 2 sigma errors of < 2 m.y. for different stages of the Ordovician Period [about 500 to 440 million years ago], improving upon the precision obtained in earlier studies by an order of magnitude. Laser probe 40Ar/39Ar dating...[reference omitted] has been used WITH SUCCESS to date impact craters and ash beds... [references omitted]. Both of these techniques permit the DETECTION AND ELIMINATION of spurious data resulting from the presence of detrital grains in the material under study...[reference omitted], and they open up new avenues for PRECISE and ACCURATE calibration of the geologic time scale.' [my emphasis]

As shown by the more complete quotations from Baksi (1990, p. 985-986), Woodmorappe (1999, p. 8) leaves out some very relevant information. In particular, Baski (1990, p. 985) states that long ago Dalrymple (the main target of Woodmorappe's, 1999, wrath) and Lanphere helped geologists to identify some of the earlier problems in K-Ar dating.  Also, Baksi (1990) is optimistic that future data sets will be able to evaluate the periodicity hypothesis. 

Woodmorappe's own lack of objectivity can be readily seen in how he (1999, p. 37-38) misuses the following quotation from Marshall et al. (1986, p. 451) to claim that scientists use 'posterioritic reasoning' to subjectivity select some radiometric dates and reject others:

'In the following analysis, several criteria are used for interpreting the reliability of K-Ar dates.  First, any date with a high error (i.e., the +/-) is treated permissive, but not diagnostic of age.  Second, the geologic context and/or study of mineral separates may indicate the possibility of an older detrital component which COULD correspond to anomalous results. ... Third, the overall interpretation of a suite of dates is made by comparing all the dates, taking into consideration their stratigraphic relations, analytical quality, and their internal consistency on dates for different minerals.  THIS PROCESS INEVITABLY REMAINS SOMEWHAT SUBJECTIVE and it is therefore important to have, whenever possible, multiple dates for each mineral and to date as many phases per sample as possible.  The multiple dates presented in this study thus establish a more objective basis for rejection of some dates, particularly IF suspect dates correlate with observable problems such as alteration and/or contamination.' [Woodmorappe’s emphasis]

By using different rational criteria, Marshall et al. (1986, p. 451) shows how to minimize subjectivity when evaluating the reliability of radiometric dates. Furthermore, as indicated by the ellipse in the above quotation, Woodmorappe (1999, p. 38) omits the following statements, which indicate that the reasons for rejecting certain dates as being anomalously young are often obvious and are far from being subjective:

'Thus, if replicate dates are available for a particular sample of reworked tuff, then the younger date(s) is (are) more likely correct. Some minerals, particularly biotite and glass, are often suspect because of possible air argon loss resulting from post eruptive alteration.  This alteration is READILY apparent when the sample is analyzed under a light microscope and the degree of alteration often correlates with anomalously young ages.' [my emphasis]

Sometimes, unaltered and uncontaminated rocks and minerals are not available and scientists must date less-than-ideal samples (e.g., Sinton et al., 1998; Lamb and Cox, 1998; Baksi, 1999). Depending upon whether the samples are altered or contaminated, the radiometric dates may represent minimum or maximum ages.   Nevertheless, how can scientists’ reasoning be 'posterioritic', when scientists know that visibly altered materials may only provide minimum ages?  Furthermore, if the Earth is only '10,000 years old', why is it that the chemistry of many samples provides MINIMUM dates of millions of years?  Without invoking groundless miracles, where did all of the daughter products come from? Considering how this section undermines his agenda, it's not surprising that Woodmorappe (1999, p. 38) edited it out of his quotation.

Woodmorappe (1999, p. 37) further argues that the credibility of radiometric dates is just a matter of 'opinion'.  To 'prove' his accusations, he (1999, p. 37) quotes Magaritz and Taylor (1986, p. 2194) and states that the reliability of their dates is not obvious:

'It is very difficult to separate the K/Ar effects of intrusive (plus hydrothermal) events versus simple uplift events.'

The quotation, in context, is not as serious as Woodmorappe (1999, p. 37) would have us believe:

'In some cases, it may be justified to use the K/Ar method to give us the age of the youngest intrusive or thermal event and thus date the age of the youngest hydrothermal system in a given area ...[references omitted].  In fact, middle to early Tertiary intrusions are widespread in southern British Columbia, Washington, and Idaho.  However, during the early Tertiary, wide areas in south central British Columbia were also affected by a thermal event recorded by K/Ar resetting in regionally metamorphosed rocks ... [references omitted].  It is very difficult to separate the K/Ar effects of intrusive (plus hydrothermal) events versus simple uplift events.  In some cases they operate simultaneously... [reference omitted].'

When Magaritz and Taylor's (1986, p. 2194) comments are read in context, Woodmorappe’s (1999, p. 37) conclusions become non-sequitur, that is, his conclusions do not follow from the quotation.  Firstly, Magaritz and Taylor (1986, p. 2194) are referring to a very complex geological terrane in southern British Columbia and the sentence that Woodmorappe quotes may not apply to other areas with less complex geological histories.  Secondly, just because the causes of K-Ar dates are difficult to identify that doesn’t mean that the research is subjective guesswork.  Sometimes, through hard work, difficult problems are solved and the solutions provide objective, reliable and conclusive results. In particular, Magaritz and Taylor (1986) were able to successfully unravel some of the complex geologic history of the region by using radiometric dating, stable isotope analyses and other techniques.

Woodmorappe (1999, p. 37) also quotes Gale and Beckinsale (1983, p. 297) and sees 'evidence' of 'subjectivity' when calibrating the 'Phanerozoic' time scale:

'There is no radiometric date yet reported which has been proved to be so completely reliable that it can be used as an anchor point in calibrating the Palaeozoic time scale. Such a calibration must instead be based on all available reliable data...'

A more complete quotation of Gale and Beckinsale (1983, p. 296-297) states:

'There is an unfortunate emphasis... [reference omitted] on the Rb-Sr whole rock isochron date for the Stockdale Rhyolite... [reference omitted].  There is no radiometric date yet reported which has been proved to be so completely reliable that it can be used as an anchor point in calibrating the PALAEOZOIC time scale. Such a calibration must instead be based on all available reliable data... [references omitted]  [new paragraph] Though undue weight should not be given to the Stockdale Rhyolite age of 421 +/- 5 Ma [million years ago] (2 sigma error) for the Ashgill, nevertheless Ross et al. have presented no data which refutes it.' [my emphasis, Paleozoic NOT Phanerozoic]

While Woodmorappe (1999, p. 37) sets up a strawperson argument and criticizes scientists for failing to agree upon 'absolute' values for the Phanerozoic time scale, Gale and Beckinsale (1983, p. 296-297) states the obvious.  That is, all data must be independently verified.  Furthermore, contrary to Woodmorappe's (1999, p. 37) mistaken views, there are NO absolute values anywhere in science.  No analytical data have such absolute certainty that they can stand by themselves in perpetuity.  All scientific data have errors and uncertainties, including the measured distance from the Earth to the Moon at any given time and the dates that are used to calibrate the geologic time scale (Harland, 1983).  Correctly, scientists are always striving to improve the accuracy and precision of their analytical methods.

A decent time scale calibration involves the careful use of a variety of independent radiometric and non-radiometric data (e.g., Harland et al., 1990).  In the past few years, the uncertainties associated with the boundaries between the periods in the Phanerozoic time scale generally have been reduced to below 5%.  See Radiometric Dating and the Geologic Time Scale.  In contrast to Woodmorappe's (1999, chapters 5 and 9) serious misunderstandings about the basic nature of science and how radiometric dates are derived and interpreted, Dr. Andrew MacRae concisely states at Radiometric Dating and the Geologic Time Scale:

'Skeptics of conventional geology might think scientists would expect, or at least prefer, every date to be perfectly consistent with the current geological time scale, but realistically, this is not how science works. The age of a particular sample, and a particular geological time scale, only represents the current understanding, and science is a process of refinement of that understanding. In support of this pattern, there is an unmistakable trend of smaller and smaller revisions of the time scale as the dataset gets larger and more precise... [reference omitted]. If something were seriously wrong with the current geologic time scale, one would expect inconsistencies to grow in number and severity, but they do not.'


For decades, very powerful statistical methods and other highly objective criteria have been available for interpreting radiometric data. Nevertheless, ALL data interpretation has a subjective component.  This is not only true for geochronology, but also for predicting the weight limit of a bridge, measuring pollutants in groundwater, performing X-ray diffraction analyses on a sediment, counting fish in the ocean, and mapping rock types.  Specifically, no two people will contour elevations on a topographic map in exactly the same way. 

Powder X-ray diffraction is often used to identify minerals in rocks and sediments. Computers may not always find peaks on X-ray diffraction diagrams that are obvious to the human eye, and some individuals may see 'peaks' that are really background noise. 

Nevertheless, as with drawing contours for topographic maps or interpreting peaks on X-ray diffraction diagrams, there are general rules to guide and restrict the interpretations of radiometric data and minimize subjectivity (e.g., McDougall and Harrison, 1999, chapter 4).  Because Woodmorappe (1999) is so concerned about the validity and objectivity of radiometric dates, from my laboratory experience, I hope that he is at least as concerned about the far less thorough and less accurate chemical and biological analyses that are routinely used to verify that his drinking water and packaged food are free of harmful concentrations of toxins and bacteria.


Clearly, radiometric dating methods are not as 'plastic' as Woodmorappe (1999) would have us believe.  Furthermore, when we review the articles that Woodmorappe (1999) cites, we see that the authors of these articles widely recognize that radiometric dating methods are very useful and reliable (for a few examples, see Important Statements on Radiometric Dating in Woodmorappe's References that He Doesn't Want You to See.  Obviously, Woodmorappe (1999) is blatantly biased and is grossly exaggerating the problems with radiometric dating and totally neglecting the numerous strengths of these methods.

Any problems with subjectivity in radiometric dating are minuscule when compared to the subjectivity and inconsistencies in young-Earth creationism and other aspects of fundamentalist Christianity.  If a Bible verse vaguely guesses or accidentally pokes at some scientific discovery, the Christian fundamentalists loudly proclaim it as evidence of 'divine inspiration' (e.g., Job 26:7; Is 40:22; Morris, 1986).  If the verses (e.g., the Earth has 'pillars' according to Job 9:6 and the 'immoveable Earth' of 1 Chronicles 16:30; Is 45:18 and Psalms 93:1, 96:10 and 104:5) conflict with well-known, popular and indisputable scientific facts, the verses are either ignored or YECs use their boundless imaginations to remold the interpretations of the verses to conform to popular science (e.g., Morris, 1986).  The new interpretations are then proclaimed as the perpetual 'Truth'.  This 'tails, I win; heads, you lose' approach to interpreting the Bible gives the book a false air of inspiration and infallibility. 

The constant in-fighting among fundamentalist Christians over infant baptism, the 'gifts' of the Holy Spirit, keeping a Sunday 'Sabbath', salvation by grace alone, and countless other issues clearly demonstrates that their biblical interpretations are far more 'plastic', subjective, and unreliable than radiometric dating (Matthew 7:3-5).  Specifically, conservative Lutherans and conservative Baptists quote the same Bible and derive opposite conclusions about infant baptism.  Furthermore, YECs can't even agree about whether or not a 'vapor canopy' existed before the 'Flood'.  YECs Kofahl (1977) and Johnson (1986) cite Genesis 1:7 as 'evidence' of a 'vapor canopy', yet they admit that miracles would have been needed to prop up this mythical structure.   At the same time, YECs Brown (1995, p. 174-179) and Whitelaw (1983) read the same Bible and reject the existence of a 'Pre-flood canopy'.

Bob Jones 'University' is located in Greenville, South Carolina.  This 'Christian university' is ultrafundamentalist and strongly supports young-Earth creationism.

In a radio speech on April 17 1960, Bob Jones Sr., founder of the 'university', attacked desegregation as being 'anti-God' (see "Preaching the Anti-Evolution Propaganda".) According to Jones, Acts 17:26 states that God has 'set' boundaries between the different 'races' (nations) and that desegregation is a 'violation' of these boundaries. Later, when minorities were admitted to the 'university', interracial dating was prohibited, probably on the basis of this racist interpretation of Acts 17:26. 

For decades, leaders in the Civil Rights Movement, sensible theologians, and more liberal Bible-quoting evangelicals could never succeed in convincing the leaders of Bob Jones 'University' to change their archaic and racist policies.  However, after a series of scathing speeches by Senator McCain during the 2000 Presidential campaign and pressure from television talk-show host Larry King, Bob Jones III of Bob Jones 'University' forgot about his grandfather's uncompromising pronouncement on Acts 17:26, denied that segregation was 'scriptural' and dropped the 'university's' decades-old prohibition on interracial dating.  Without using a Bible and over the course of just a few days, Senator McCain, Larry King and other secular critics did what sensible Christians couldn't do.  They persuaded the 'university' leadership to abandon one of its racist policies.  So much for fundamentalists' claims that the Bible is an 'objective', straightforward', 'powerful', 'steadfast' and 'never-ending' standard.  In contrast, when was the last time that a YEC Senator succeeded in using public and political pressure to persuade the United States Geological Survey to change its views on the age of the Earth?


Baksi, A.K., 1990, 'Search for Periodicity in Global Events in the Geologic Record: Quo Vadimus?', Geol., v. 18, p. 983-986.

Baksi, A.K., 1999, 'Reevaluation of Plate Motion Models Based on Hotspot Tracks in the Atlantic and Indian Oceans', J. of Geol., v. 107, p. 13-26.

Brown Jr., Walter T., 1995, In the Beginning..., 6th general edition, Center for Scientific Creation, Phoenix, AZ.

Dalrymple, G.B. and M.A. Lanphere, 1969, Potassium-Argon Dating, Freeman, San Francisco.

Gale, N.H. and R.D. Beckinsale, 1983, 'Comments on the Paper "Fission-track Dating of British Ordovician and Silurian Stratotypes" by R.J. Ross and Others', Geol. Mag., v. 120, n. 3, p. 295-302.

Harland, W.B., 1983, 'More Time Scales', Geol. Mag., v. 120, n. 4, p. 393-400.

Harland, W.B.; R.L. Armstrong; A.V. Cox; L.E. Craig; A.G. Smith; and D.G. Smith, 1990, A Geologic Time Scale 1989, Cambridge University Press, Cambridge.

Harrison, T.M., 1990, 'Some Observations on the Interpretation of Feldspar 40Ar/39Ar Results', Chem. Geol. (Isotope Geosci. Sec.), v. 80, p. 219-229.

Johnson, Gary L., 1986, 'Global Heat Balance with a Liquid Water and Ice Canopy', Creation Research Society Quarterly, v. 23, September, p. 54-61.

Kofahl, Robert E., 1977, 'Could the Flood Waters have Come from a Canopy or Extraterrestrial Source?', Creation Research Society Quarterly, v. 13, March, p. 202-206.

Krough, T.E., 1982, 'Improved Accuracy of U-Pb Ages by the Creation of More Concordant Systems Using an Air Abrasion Technique', Geochim. et  Cosmochim. Acta, v. 46, p. 637-642.

Lamb, M.A. and D. Cox, 1998, 'New 40Ar/39Ar Age Data and Implications for Porphyry Copper Deposits of Mongolia', Econ. Geol., v. 93, p. 524-529.

Margaritz, M. and H.P. Taylor, Jr., 1986, 'Oxygen 18/Oxygen 16 and D/H Studies of Plutonic Granitic and Metamorphic Rocks Across the Cordilleran Batholiths of Southern British Columbia', J. Geophys. Res., v. 91, n. B2, p. 2193-2217.

Marshall, L.G.; R.E. Drake; G.H. Curtis; R.E. Butler; K.M. Flanagan and C.W. Naeser, 1986, 'Geochronology of Type Santacrucian (Middle Tertiary) Land Mammal Age, Patagonia, Argentina', J. of Geol., v. 94, p. 449-457.

McDougall, I. and T. M. Harrison, 1999, Geochronology and Thermochronology by the 40Ar/39Ar Method, 2nd ed., Oxford University Press, New York.

Morris, H.M., 1986, Science and the Bible, Moody Press, Chicago.

Sinton, C.W.; K. Hitchen and R.A. Duncan, 1998, '40Ar-39Ar Geochronology of Silicic and Basic Volcanic Rocks on the Margins of the North Atlantic', Geol. Mag., v. 135, n. 2, p. 161-170.

Tucker, R.D., 1989, 'Time-scale Calibration Employing the High-precision U-Pb Zircon Ages of Interstratified Tephras of the Ordovician Stratotype of Britain', GSA Abs. Prog., v. 21, n. 6, p. A134.

Whitelaw, Robert L., 1983, 'The Fountains of the Deep, and the Windows of Heaven', in Science at the Crossroads: Observation or Speculation?, papers of the 1983 National Creation Conference, Bible-Science Association and Twin Cities Creation-Science Association, Minneapolis, MN, p. 95f.

Woodmorappe, J., 1999, The Mythology of Modern Dating Methods, Institute for Creation Research, El Cajon, CA.

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