How does one know that measurable amounts of argon (which there was in Austin example) are due to “slow decay” that you state? There isn’t any way to know, you assume it by super powers of magic eyesight, apparently.
Actually, due to the gaseous nature of argon it's virtually certain that 99% of the time the argon in appropriately selected and properly prepared samples is due to great age and radioactive decay of potassium. Argon tends to bubble out of liquids ...
But that notwithstanding, there
are ways to know that the measureable amounts of argon are due to slow decay, one ofwhich is the argon-argon method.
I suggest you learn something of how radiometric dating
actually works.
Radiometric Dating: A Christian Perspective is a classic and accurate resource.
Maybe a few of our dates are wrong because of the potential problem you cite. The vast majority of them aren't wrong.
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