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Research:Radioactive dating

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This page contains research notes for the Radioactive dating article.
See Research for more information on research pages.


General references

A Christian Response to Radiometric Dating, by Tasman B. Walker - This reproduces Radiometric Dating: A Christian Perspective, by Dr. Roger C. Wiens, and gives a blow-by-blow rebuttal.

Astronomical dating

  • K. F. Kuiper, A. Deino, F. J. Hilgen, W. Krijgsman, P. R. Renne, J. R. Wijbrans, Synchronizing Rock Clocks of Earth History, Science 25 April 2008: Vol. 320. no. 5875, pp. 500 - 504; DOI: 10.1126/science.1154339 - This is a research paper, so it is very technical. It is also very recent. There are several good illustrations. The correlation does not jump out and punch you in the eye, but reveals itself with careful study.
    • Two Geologic Clocks Finally Keeping the Same Time, Richard A. Kerr, NEWS OF THE WEEK (25 April 2008), Science 320 (5875), 434. [DOI: 10.1126/science.320.5875.434] - The associated news story, less detailed, more accessible. Makes clear that the dating of the sediments is done via minerals in volcanic ash layers interspersed in the sediments. Also discusses the implication for the dating of the large extinction events, their association with volcanic eruptions, and the agreement between K-Ar dating fo the sediments and U-Pb dating of the lava flows. The adjustment of 0.65% makes dramatically clear how much explaining critics of radiometric dating have to do.
    • Links to 13 articles that cite this one.
    • "We avoid these drawbacks by applying the single-crystal 40Ar/39Ar dating method to sanidine phenocrysts extracted from numerous silicic tephra layers intercalated in an astronomically tuned open marine succession from the Messinian Melilla Basin in Morocco."
  • has a series of pages providing brief and clear explanations of several aspects of ATS, Astronomical Time Scale
    • Absolute astronomical time - Figure showing data. "Sapropels and/or carbonate cycles in the Mediterranean Narbone Formation and Trubi Marls were tuned to summer insolation 65° North with a 3-kyr lag between insolation maxima and sapropel (or low-carbonate grey-layer) midpoint."
    • Floating astronomical time - Figure showing data. "Lower Cretaceous (Albian) deep-sea sediments (coccolith/globigerinacean marls) of the Umbria-Marche Apennines were drilled in 1979 near Piobbico, Italy. The drillcore revealed sustained, rhythmic sedimentary bedding, with drab facies representing normal stratified conditions, and red facies indicating downwelling warm saline waters. The drab facies is overprinted by cm- to dm-scale redox oscillations; these oscillations occur with a strong 5:1 bundling pattern."
    • Earth's Orbital Parameters
    • Orbitally Forced Insolation
    • Precision and Accuracy of the ATS - "At the present time, models of Earth's orbital variations are reliably accurate over the past 50 Ma (Laskar et al., 2004). Prior to this time, expectations for chaotic behavior in the solar system casts uncertainty on the modeled orbits."
  • Linda A. Hinnov and James G. Ogg, Cyclostratigraphy and the Astronomical Time Scale, stratigraphy, vol. 4, nos. 2/3, pp. 239-251, figures 1-2, 2007. - Another scientific paper (link provided by Part of an issue on BEYOND THE GSSP: NEW DEVELOPMENTS IN CHRONOSTRATIGRAPHY, with a number of interesting titles. Note also the reletively recent date.
    • "An important innovation in the International Geologic Time Scale 2004 is the use of astronomically forced stratigraphy, or cyclostratigraphy, to define geologic time over 0 to 23.03 Ma, much of it at an unprecedented resolution of 0.02 myr. In addition, ‘floating’ astronomical time scales with 0.10 to 0.40 myr resolution are defined for entire epochs and stages in the Paleogene and all three Mesozoic periods. Some of these calibrations use a new astronomical model with an hypothesized high accuracy over 0-250 Ma."
    • "FIGURE 1: Astronomical forcing of the ancient sedimentary record."
    • "The Cenozoic ATS is nearly complete. The scale is constructed from overlapping paleoclimate proxy records from the Mediter- ranean, Atlantic and Pacific basins, tied to the geomagnetic po- larity sequence and global biostratigraphic zones."
  • New Astronomical Results Refine The Geological Time Scale, ScienceDaily (Nov. 3, 2004) - another news article. A bit older than the others. Talks more about the astronomical calculations.

These are about establishing a connection between astronomical cycles and radioactive dating. It is work from the past decade and now covers dates as early as 32 million years ago. If the radioactive decay rates were miraculously increased during the flood, then the development of orbital parameters must have been accelerated in just the same way.

University of Waikato radiocarbon dating sample record sheet

Waikato Uni carbon dating form p.1.pngWaikato Uni carbon dating form p.2.png

Anomalous dates

This section lists examples of radiometric dates which are inconsistent with known dates, inconsistent with each other, seriously inconsistent with the uniformitarian timescale, or inconsistent with other evidence.

Inconsistent with known dates

The five examples listed here are all cited in

The first one (Mt. St. Helens) is the subject of the article. The other five are quoted from

  • Dalrymple, G.B., 40Ar/36Ar analyses of historic lava flows, Earth and Planetary Science Letters, 6:47–55, 1969.

In each case the K-Ar method is applied to a historical lava flow of known age less than 2200 years, and the radiometric age is calculated to be between a few hundred thousand and a few million years.

Mt. St. Helens
  • In 1996 rocks from the 1980s eruption of Mt. St. Helens were dated with potassium-argon dating to be 340,000 to 2.8 million years old.
  • Lava flows from eruptions in Hawaii in 1800/01 were dated with potassium-argon dating to 1.46 million to 1.6 million years old.
Mt. Etna
  • Basalt from a 122 B.C. eruption of Mt. Etna gave an age with potassium-argon dating of 250,000 years.
  • Basalt from a 1792 eruption gave an age with potassium-argon dating of 350,000 years.
Mt. Lassen (California)
  • Plaglioglase formed on Mt. Lassen in 1915 dated with potassium-argon dating to 110,000 years old.
Sunset Crater (Arizona)
  • Basalt formed in 1064-65 dated to 250,000-270,000 years of age.

Inconsistent with each other

Mexican quarry

A British team reported finding markings in a layer of volcanic ash in a Mexican quarry that they interpreted as human footprints. Their measurements on quartz crytals found in the ash using Optically Stimulated Luminescence (OSL) indicated an age of 39 +/- 9 thousand years, but subsequent measurements by a team from Berkeley using the Ar-Ar method yielded an age of 1.3 +/- 0.03 million years. OSL is a non-radioactive technology to determine the time since certain crystals were last exposed to sunlight or last heated above 400 degrees, and is typically applied to sediments thought to be 300 to 100,000 years. After further investigations of the markings, including statistical comparisons to other findings of human and hominid footprints, the claim that these markings were human footprints was withdrawn.

Grand Canyon

The Cardenas basalt at the bottom of the Grand Canyon was dated by the Rubidium-Strontium method to 1,070 million years (McKee and Noble, 1976), whereas lava which flowed into the canyon after it was cut—and therefore should be much younger—was dated with the same method to 1,340 million years (Austin, 1992). Whole rock samples from (in the first case) six or (in the second case) four different different lava flows were analyzed, a technique which only gives the age of the flows if they occurred at nearly the same time fed by an isotopically well-mixed source. Otherwise, the age returned, if it is meaningful at all, is the time since the material was last mixed, which might have been deep in the mantle. A more extensive study of the upper lava flows, with 20 samples, was done by Leeman already in 1974. He found a significant (>95%) correlation between the Sr87/Sr86 and Rb/Sr ratios (equivalent to an isochron) only for the four samples which showed independent signs of contamination from crust material. Mixing of two reservoirs with different compositions is one of the ways a straight line can be produced in an isochron plot that has no relation to the age of the material. Whether this has actually occured can usually be determined by plotting the data is a different way.[1]

Mungo Man

In 1969 over 175 bone fragments were found on the edge of dry Lake Mungo in New South Wales. They were the remains of a woman, and were carbon dated to between 24,500 and 26,500 years old. Five years later more remains, this time of a man, were found 300 metres away. It has not been possible to use carbon dating on these remains, but the initial publication by their discoverer, Jim Bowler, and Alan Thorne estimated the age to be 28,000 to 32,000 years on the basis of geomorphological criteria and stratigraphic association with the previous find. In 1999 Thorne argued for an age of 62,000 ± 6,000 years based on new results using three different techniques (uranium series, electron spin resonance, and optically stimulated luminescence). That study was criticized in the professional literature on a variety of grounds. In 2003 Bowler presented a review of the dating attempts, including OSL data from 25 new samples. His conclusion was an age of 40 ± 2 kyr for both finds, which seems to have become a durable concensus.

This story provides a case study of the difficulties and limitations of dating human remains, especially near the “event horizon”, which is now about 50,000 years with the best available technology. In retrospect, some of the controversy arose because various effects (like contamination of the bones with recent carbon) added systematic error to the dating results, and some arose because the age of related objects (like the layer of sand in which the body was buried) could not be directly transfered to the find itself. The intensity of the controversy was doubtless fueled by the significance the older date would have on the field of human origins, particularly in relation to the theory that had been proposed by Thorne. The ages proposed at various times differed by up to a factor of two, compared to the ±5% error estimate of the current consensus. The extreme value propagated by Thorne was in the end about three of his error bars removed from the value later accepted.

Dating around Mungo 3
author published method object age BP challenged by challenged because
Bowler and Thorne 1976 geomorphological criteria and stratigraphic association with Mungo 1 28,000 to 32,000
Caddie 1987 ESR bone 31,000±7000 Grün and Schwartz ESR should not be applied to bone
Thorne et al. 1999 ESR dental enamel 62,000 ± 6,000
(during or before oxygen isotope stage 4, i.e. 57,000-71,000)
"The bottom of the Mungo Unit from which LM3 was recovered has been securely dated to 43,000 years. Given that the grave of LM3 must have been dug from a higher, and therefore younger, land surface there is little possibility that the LM3 burial can be older than 43,000 years."[2]

Bowler et al. 2003: The OSL samples used to date LM3 by Thorne et al (1999) had little, if any, stratigraphic relationship with the original burial.

U-series calcite crust covering the skeleton
OSL sediment surrounding the skeleton
Bowler 2003 OSL 25 new samples 42,000 to 45,000
(or < 50,000)
Spooner ≥2003 ? ? 44,000

Java Man

The homo erectus fossils from Indonesia were dated in 1996 at 30,000 to 50,000 years of age, using analysis of radioactive elements in fossil-bearing sediment. However, new dates published in 2010 based on argon decay in rocks above and below the fossils gave their age as about 550,000 years.

Inconsistent with the uniformitarian timescale

Hawkesbury Sandstone
  • An item that appeared to be petrified wood was found by a local resident in a crack in a block of Hawkesbury Sandstone, believed by conventional geologists to be 225–230 million years old. He turned the sample over to creationist Andrew Snelling, who submitted it to Geochron Labs for carbon-14 analysis, which, when interpreted as an age, returned 33,720±430 years. The head of the Radiocarbon Group at Geochron Labs has expressed doubt that the sample was wood at all. 33,700 years is 5.9 times the half-life of carbon-14, and 25.9 is 60, so contamination with modern carbon at the 2% level would be sufficient to give this result. Contamination could occur, for example, through percolation of rainwater while the sample was still buried or through less than meticulous handling during sample collection.

Inconsistent with other evidence

Devils Postpile (California)
  • Basalt from Devils Postpile dates with potassium-argon dating to 940,000 years ago, although stratigraphic study puts the rock as being less than 100,000 years old.[3]
Keramim (Israel)
  • Basalt from Keramim dates with potassium-argon dating to 250,000 years ago, but has 'stone age' artefacts underneath it.[4]
Hornton Quarries (England)
  • Limestone in the Marlstone Rock Bed at Hornton Quarries was dated by index ammonite fossils at about 189 million years old, but has embedded wood dated with carbon dating between 20,000 and 30,000 years old.[5]

C-14 levels in ancient carbon

  • Fossils older than 100,000 years should have too little 14C to measure, but dating labs consistently find 14C, well above background levels, in fossils supposedly many millions of years old.21,22 For example, no source of coal has been found that lacks 14C, yet this fossil fuel supposedly ranges up to hundreds of millions of years old. Fossils in rocks dated at 1–500 Ma by long-age radioisotope dating methods gave an average radiocarbon ‘age’ of about 50,000 years, much less than the limits of modern carbon dating22 (see pp. 65–69 for why even these radiocarbon ages are inflated). Furthermore, there was no pattern of younger to older in the carbon dates that correlated with the evolutionary/uniformitarian ‘ages’.
  • Even Precambrian (‘older than 545 Ma’) graphite, which is not of organicorigin,contains14Cabovebackgroundlevels.22 Thisisconsistent with Earth itself being only thousands of years old, as a straightforward reading of the Bible would suggest.
  • Measuring notable levels of 14C in samples intended as procedural blanks or “background” samples is a phenomenon that has persisted from the earliest days of AMS down to the present time. For example, Vogel, Nelson, & Southon (1987) describe their thorough investigation of the potential sources and their various contributions to the 14C background in their AMS system. The material they used for the blank in their study was anthracite coal from a deep mine in Pennsylvania. An important part of their investigation was variation of the sample size of the blank by a factor of 2000, from 10 μg to 20 mg. They found that samples 500μg and larger displayed a 14C concentration of 0.44±0.13pmc, independent of sample size, implying this 14C was intrinsic to the anthracite material itself. For samples smaller than 500μg, the measured 14C could be explained in terms of this intrinsic 14C, plus contamination by a constant amount of modern carbon that seemed to be present regardless of sample size. After many careful experiments, the authors concluded that the main source of this latter contamination was atmospheric CO2 adsorbed within the porous Vicor glass used to encapsulate the coal sample in its combustion to CO2 at 900°C. Another source of smaller magnitude was CO2 and CO adsorbed on the walls of the graphitization apparatus retained from reduction of earlier samples. It was found that filling the apparatus with water vapor at low pressure and then evacuating the apparatus before the next graphitization mostly eliminated this memory effect. Relative to these two sources, measurements showed that storage and handling of the samples, contamination of the copper oxide used in combustion, and contamination of the iron oxide powder used in the graphitization were effectively negligible. And when the sample size was greater than 500μg, the intrinsic 14C in the coal swamped all the sources of real 14C contamination. Rather than deal with the issue of the nature of the 14C intrinsic to the anthracite itself, the authors merely refer to it as “contamination of the sample in situ”, “not [to be] discussed further.”
  • The laboratory claims most of their quoted system background arises from sample processing. This processing involves combustion (or hydrolysis in the case of carbonate samples), acetylene synthesis, and graphitization. Yet careful and repeated analysis of their methods over more than 15 years have convinced them that very little contamination is associated with the combustion or hydrolysis procedures and almost none with their electrical dissociation graphitization process. By elimination they conclude that the acetylene synthesis must contribute almost all of the system background. But they can provide little tangible evidence it actually does.
  • Other RATE projects are building a compelling case that episodes of accelerated nuclear decay must have accompanied the creation of the earth as well as the Genesis Flood (Baumgardner, 2000; Humphreys, Baumgardner, Austin, & Snelling, 2003; Snelling & Armitage, 2003). We believe several billions of years worth of cumulative decay at today’s rates must have occurred for isotopes such as 238U during the creation of the physical earth, and we now suspect a significant amount of such decay likely also occurred during the Flood cataclysm. 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 fact that significant amounts of 14C are measured routinely in fossil material from organisms alive before the cataclysm argues persuasively that only a modest amount of accelerated 14C decay occurred during the cataclysm itself. This suggests the possibility that the fraction of unstable atoms that decayed during the acceleration episode for all of the unstable isotopes might have been roughly the same. If the fraction were exactly the same, this would mean that the acceleration in years for each isotope was proportional to the isotope’s half-life. In this case, if 40K, for example, underwent 400Ma of decay during the Flood relative to a present half- life of 1250Ma, then 14C would have undergone (400/1250)*5730 years = 1,834 years of decay during the Flood. This amount of decay represents 1–2-(1834/5730)=20% reduction in 14C as a result of accelerated decay. This is well within the uncertainty of the level of 14C in the pre-Flood world so it has little impact on the larger issues discussed in this paper.
  • The data already present in the peer-reviewed radiocarbon literature suggests there is indeed intrinsic 14C in such materials that cannot be attributed to contamination. If this conclusion proves robust, these reported 14C levels then place a hard limit on the age of the earth of less than 100,000 years, even when viewed from a uniformitarian perspective.
  • Nadeau M-J, Grootes PM, Voelker A, Bruhn F, Oriwall A, 2001. Carbonate 14C background: Does it have multiple personalities? Radiocarbon 43 (2A), 169–176. (abstract)
  • Measurements of the radiocarbon concentration of several carbonate background materials, either mineral (IAEA C1 Carrara marble and Icelandic double spar) or biogenic (foraminifera and molluscs), show that the apparent ages of diverse materials can be quite different. Using 0.07 pMC obtained from mineral samples as a processing blank, the results from foraminifera and mollusc background samples, varying from 0.12 to 0.58 pMC (54.0-41.4 ka), show a species-specific contamination that reproduces over several individual shells and foraminifera from several sediment cores. Different cleaning attempts have proven ineffective, and even stronger measures such as progressive hydrolization or leaching of the samples prior to routine preparation, did not give any indication of the source of the contamination. In light of these results, the use of mineral background material in the evaluation of the age of older unknown samples of biogenic carbonate (>30 ka) proves inadequate. The use of background samples of the same species and provenance as the unknown samples is essential, and if such material is unavailable, generic biogenic samples such as mixed foraminifera samples should be used. The description of our new modular carbonate sample preparation system is also introduced.

Correlations between radiometric dates and incremental dates

"Radio isotope dating, using 210Pb (lead) (Crozaz & Langway, 1966), 32Si (silicon), 39Ar (argon) (Oeschger et al., 1977) and 14C (carbon) (Paterson et al., 1977) have all been used with varying degrees of success, over different time scales, to determine the age of ice cores."
Oeschger, H., Stauffer, B., Bucher, P. & Loosli, H.H., 1977. Extraction of gases and dissolved and particulate matter from ice in deep boreholes. In: Isotopes and impurities in Snow and Ice, International Association of Scientifc Hydrology Publication No. 118. IASH, Washington D.C., pp. 307-311.

Variability with time

Helium Diffusion Age of Zircons

Helium Diffusion in Zircons — Does it show that the earth is young? - links to articles on both sides



Radiohalos in Granites



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