No, they are not, at least not in any physically relevant situation.
And of course you haven't thought things through, you're just spewing any nonsense that comes into you head. If the decay of heavy isotopes has been slowed then the dates we are measuring are too young. That is, the samples would be significantly older that our measurements say they are.
I suggest you think that through. Rates are slow now. This means that they overestimate time periods when comparing ratios of parent to daughter isotopes. Without the slowdown, rocks would rapidly decay into daughter isotopes which I believe is what happened from about 4400 years ago until about 1700 years ago. (approximately).
Ah, I see. It's an incredibly stupid idea, but I see. So you think that what we see as 253 million years of decay is really 2,700 years of decay, or a factor of about 100,000 speed up.
Let's look at self-irradiation. From the link you're trying so hard to avoid, human self-irradiation today due to decay of
40K is about 100 or more μSv/year. Speeding up decay by a linear factor of 100,000 over those 2,700 years results in self-irradiation of 10 Sv/year. A 30 year old person would have been exposed to about 300 Sv. From the links in the message you are so afraid of, 4-5 Sv kills 50% of exposed people in 30 days, and 6 Sv results in a 90% death rate and more at higher levels. So we're looking at a level of self-irradiation that is on the order of 30 times the dose that kills 90% of the people. And you think that humans never noticed that high death rate from radiation poisoning with the attendant sores and vomiting and whatnot? And you believe the human race (and all other life) could survive that?
Making the decay speedup nonlinear would make it even worse.
Oh, and your scenario requires that Hezikiah's tunnel (
Wikipedia) was dug long before Hezikiah reigned. Got it.
There's more. Heat. Consilience between different methods using isotopes that decay by different mechanisms. Consilience with non-radiometric methods.
It just doesn't fly.
Edited by JonF, : No reason given.