Help Me Understand

[Thumpalumpacus]

As for radiometric dating, I'll have to get home and on my computer. It's a little too complex to handle on my phone without clear references handy.

Given that we have several different checks on the accuracy of radiometric dating, the fact that a few percent of those samples return anomalous dates is quickly discovered -- that is exactly where the data touted by YECers comes from: double-checking.

Firstly, many rocks are susceptible to multiple types of radiometric dating. In the vast majority of cases, the different decay cycles agree with each other. In order to argue that one method is wrong, you would have to argue that all the other methods used on a given rock were not only wrong, but somehow produced the same error.

Secondly, we can observe radiometric decay in progress by viewing supernovae. Such stellar explosions produce copious amount of decaying elements, and by spectrographic analysis over time, we can mark the decay of one element into another. Not surprisingly, since all elements heavier than lithium we created in the bowels of such an explosion, we can see the decay rates of radiometric yardsticks used here on Earth out in space, where they aren't affected by climate of terrestrial geology. The decay rates we see in supernovae support what is seen here on Earth.

Thirdly, it is true that anomalous geology can affect decay rates. However, if our understanding of decay rates were so badly off, what would we expect to see with the dates extrapolated? What are the odds that every mistake the world over just happened to produce an older age, and moreover, roughly the same error? If would seem more reasonable to me that the dates would be more widely scattershot, given the varied geology from which samples are collected. After all, if, say, vulcanism produces pressures and heat which advances the decay of potassium into argon, why should K-Ar errors from non-volcanic regions mirror that error, in the absence of such influences?

eta: By the way, Roadrunner, thanks for getting me to dig back into the matter. It's been a couple of decades since college geology, and the rereading was good brainfood. Thanks.