A Quick Note About Dating Methods

One of the most common Creationist claims is that the dating methods used to determine the ages of rock layers and fossils are highly faulty, amounting to little more than a vague guess. I’d like to point out some more of the hidden assumptions and implications of this claim, before demolishing it with the all-powerful two minute Google search. (I’d be very interested in any Creationist claims that can’t be remedied by an ordinary search enginge; I’ve yet to find any. As always, I’d like to point out that I’m not a scientist and have no access to specialised knowledge or resources; all of this is just lying around for anybody at all to find.)

Radiometric dating methods are an obvious target for Creationists, particularly those of the Young Earth variety. If the Earth and all of the fossils contained within are significantly younger than scientists believe, evolution as we know it is impossible (so their reasoning goes, at any rate). Actually think about that for a moment, though; the current estimate of the age of the Earth is about 4.5 billion years. A lot of Creationists won’t tell you exactly how old they think it is (guess why!), but the Biblical literalists will usually churn out something between six and ten thousand years. They’re not only suggesting that radiometric dating methods are faulty, but that they’re so faulty as to consistently give results that are off by several orders of magnitude – and Creationists are the only ones who have noticed this.

Or have they? Scientists like to be pretty sure that their tools work, and if AiG can get it together enough to realise that radiometric dating is bunk, you can be pretty certain that geologists everywhere would quickly come to the same conclusion. This implies that scientists are fully aware that their methods are hopelessly, hopelessly wrong, but continue to use them anyway.

Think about that for a moment. What possible reason would scientists have to consistently cover up their own shortcomings? I don’t want to use the phrase ‘massive Darwinist conspiracy’, but, well…that’s what the more audacious Creationists like to call it. Scientists are apparently working with faulty tools on a daily basis because they don’t like religion and think evolution is the greatest thing ever.

This is all nonsense, of course. As always, Creationists are targetting a grossly over-simplified version of science based on their own misunderstanding and ignorance.

Rock strata are dated in two different ways: relatively and absolutely. Relative dating involves determining which strata in the geological column are older or younger than the others, and usually means looking at their positions relative to each other – the younger layers sit on top of the older ones. Fossils are also used for relative dating, since certain types of fossils are associated with certain strata. (Note that the geological column and its associated fossils were determind before evolution became a dominant theory in science.)

The more contentious type of dating is absolute, in which a samples actual age is determined. Even without Creationists yammering away on the sidelines, dating isn’t easy. The Earth’s rock is constantly recycled due to tectonic activity (which is why meteorites were used to date the solar system and Earth), and there are many factors that can invalidate a result from an apparently normal sample. Thankfully, scientists are aware of these limitations and know what to look out for.

Radiometric dating works by measuring the nuclear decay of certain elements in a rock sample (the ‘parent nuclide’) into another form (the ‘daughter nuclide’).  Nuclear decay occurs according to several constants (such as an element’s half-life) which, contrary to what Creationists seem to believe, are not altered wildly according to the enviroment a rock simple finds itself in. That’s one major objection to radiometric dating; the other is that any such dating requires an assumption about the amount of the daughter isotope present when the rock sample formed.

This is actually true…to a point. While many dating methods can be thrown off by contamination, there are ways to work around it. (And again, keep in mind that the contamination is implied to be so great as to consistently give results that are wrong by billions of years.) Isochron dating is a method that does not require any assumption to be made about the amount of the daughter isotope present in a rock sample, and can be used to date igneous rock layers (among other things).

The link in the above paragraph leads to a TalkOrigins article on Isochrong dating, the result of the aforementioned two minute Google search. You’d think more Creationists would find their way over to that site, but I guess it’s kind of an internet backwater. (Either that or it’s just too darn complicated; it doesn’t seem as if Creationists are half as interested in science as they claim to be.)

So, that’s another tired Creationist claim that doesn’t hold any water. It will probably persist for a while yet, but I’ve done all I can do in that regard. Incidentally, if you’re a Creationist who buys into the faulty dating methods argument, ask yourself this: have you ever talked to a geologist or nuclear physicist about it? Have you even heard of a Creationist who has?

(NOTE: If anyone reading this is a geologist/just knows more about the subject than me, please comment with corrections for any mistakes I’ll inevitably have made.)

One Response to A Quick Note About Dating Methods

  1. […] Radiometric dating is highly flawed. I’ve covered this one before, but I’ll go over it again briefly. Radiometric dating is the measure of naturally occurring […]

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