What Should Christians think of radio-isotope dating? Part II

Updated: Mar 22

In part I, I discussed the importance of God’s creative strategy—to frame a world in literally six days. Such a strategy would require vast amounts of process condensed into a narrow window of time. Since humans interpret process in terms of time, then unbelievers (those who do not accept God’s revelatory Word) will ONLY interpret these processes in terms of time.

A little more difficult is accounting for accelerated radioisotope decay in rocks that formed during the Flood and/or in the Pre- and Post-Food worlds. Most creationist models fall very short here. Nevertheless, the RATE group has provided some data that tentatively support this model.

Of particular interest is radioisotope discordance (differing “ages” dependent upon differing isotope systems). In order to test this, the RATE group took over a hundred samples from ten different geologic “time periods” spanning more than two billion years. Importantly, the rocks from these various geologic time periods had already been dated using various radioisotope decay systems. These are K-Ar, Rb-Sr, Sm-Nd, and Pd-Pd. Each of these systems has a parent isotope, for example potassium (K), and a daughter isotope, for example argon (Ar). Simplistically, obtaining “dates” is a matter of calculating the parent/daughter ratios and then applying the corresponding decay constant.

Their results persuasively show that different systems of radioisotope pairs furnish different “ages.” This is called “discordance.” For example, in the figure below (adapted from Snelling 2005, p. 414), the Cardenas Basalt was originally dated using the Rb-Sr system at 1103 million years old. Yet when the Sm-Nd system was used on the same rocks, the “age” increased to 1588 million years. Even taking statistical error into consideration (not included in the table), the “ages” differ by about 250 million years. That’s a difference of about 20%. The K-Ar system fared even worse with an “age” of 516 million years. That’s about 50% difference!

These discordances were common across these data as a whole, and tended to trend older “ages” for heavier isotope systems (see figure below). Despite the 15 years that have elapsed since the RATE project was published in 2005, no one has cogently offered a serious rebuttal. After scanning the Internet, the best defense I could find came from Randy Isaac’s Assessing the RATE project (, “Discordances are not at all unusual and the source of discordance is not always understood but these fail to invalidate the vast amount of concordance.” I hope you caught that. To concede that discordance is not always understood while at the same time saying the results “fail to invalidate the vast amount of concordance” is nothing more than question begging. THAT was the whole point of the exercise. We must keep in mind that radioisotope dating is expensive. Only selected rocks are dated and typically only once or twice. These “ages” then set the bar for all future research at that exact location.

RATE’s results deserve better than this. I think they have truly stumbled upon an anomaly that is not being taken seriously by the secular scientific community. The discipline of geochronology has had over a hundred years to hone its methodology. And, the rest of the world are told that absolute dating is, mind the pun, “rock solid.” Yet clearly there are issues.

Ok, so where does that leave us? Scientifically, it should lead to humility not hostility. Opposing naturalists with false statements such as, “all radioisotope dating techniques are bogus” is just plain wrong. Radioisotope “ages” are factually based on geochemical relationships that do suggest millions of years’ worth of decay has occurred. However, as we have seen, Christians must allow God the right to supernaturally accelerate certain rates of change, especially when those rates pertain to earth’s structural origin (Creation Week). This is why the writer to the Hebrews says, “By faith we understand that the universe was created by the word of God” (Hebrews 11:3 ESV).

The same rationale could also be applied to the Flood since this event changed the earth's physical character. This is extremely important in light of supernatural revelation that expressly reveals God’s intervention during both of these periods. Having said that, I think supernaturally accelerated rates of radioisotope decay during the Flood be limited to a theoretical possibility rather than a theological certainty. Unlike Creation Week where all geologic rates of change were altered supernaturally, rates of change associated with the Flood were natural. This means creationists should never default to supernatural-only explanations for Flood events, even though such solutions might reflect reality. Creationists should, therefore, always be seeking naturalistic explanations for all geologic phenomena that has occurred subsequent to the Fall (the Fall altered the physical universe as did Creation Week).

Snelling, Andrew. 2005. “Isochron Discordances and the Role of Inheritance and Mixing of Radioisotopes in the Mantle and Crust.” In Radioisotopes and the Age of the Earth: Results of a Young-Earth Creationist Research Initiative. In L. Vardiman, A.A. Snelling, and E.F. Chaffin, 49-94. Dallas Texas: Institute for Creation Research, and Chino Valley: Creation Research Society. Figure adapted from the their figure on page 414.

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