What are the equal percentages of parent isotope in relation to time?

For carbon dating, the half life is 5730 years. This is roughly speaking testable, or better, the combined presumption of this halflife along with a not radically rising carbon level in the atmosphere during the last 2500 years (I could have gone one step further but was lazy) is. 477 BC to 1523 AD are historical dates. For all of this time, we have lots of detailed information of who was what and when and where, so we can state "this coffin belongs to so and so" or "this table was commissioned for so and so" and so on.

This corresponds to carbon 14 levels given with pmC values. The abbreviation pmC stands for "percent modern Carbon" and could be further explicitated as "percent modern Carbon 14 corrected to pre-Industrial Values" but that's too long to use in even abbreviated form.

Alternative to the combined assumption of 100 pmC (roughly) and 5730 years halflife, at least for this kind of test, one could imagine twice as long a halflife, but Carbon 14 still on the rise, so that back in 1180 BC it had 80 pmC rather than 100 pmC, and then a steady rise from then. That would cause a kind of "bulge" on the calibration curve, but it would be covered by the other bulges and wiggles of it.



Now the point is, these exact same percentages in Potassium dating would involve totally uncheckable (at least historically, which I consider the main go to about the past) ages. How do you check an age "108 million years ago" without a Time Machine?

The abbreviation here is for "percent original K" or "percent original potassium" (K is for the alternative name Kalium, found in German and in Nordic languages). Both methods ideally compare the % to the original content. But they arrive there different ways. In carbon dating, it's presumed the atmosphere has been at least roughly stable, so it is actually the pre-Industrial present that's key to this past original content of the parent isotope. In carbon dating, the daughter isotope isn't used at all, it doesn't matter if carbon 14 decays to nitrigen 14 or to carbon 12, I have seen both of these assumed. But in K-Ar, the original content of K (potassium) is verified by adding the current contents of K and Ar (argon).

This is not the only fudge factor about K-Ar dating. The more important one is, the dating method presumes we get all argon from either air or previous reactions before eruption nullified by the argon escaping before lava solidifies. If the lava solidifies quickly and this can happen due to lots of cold water, argon will be trapped, and it will skew the results heavily.

In the Flood (I said history was my main go to for the past, didn't I?) lots of water could cool down the lava lots quicker than it cools normally now, and trap lots more of argon.

So, when I see a date of "2 mill. years" or "4 mill. years" I think I can calibrate that too. But in a much simpler way. With that much cool water, the date is 2958 BC (or whatever date you prefer setting as the Biblical date of the Flood.)

Hans Georg Lundahl
Paris
St. Apollonia of Alexandria
9.II.2024