Sunday, November 21, 2021

How Carbon Dating is Done, Why My Calibration is Possible

Forrest Valkai to the Rescue of Radiometric Dating (Or Not?) · L M and Comparative Religion to the Rescue of Forrest Valkai? · subductionzone to the rescue of Forrest Valkai? Or Keith Levkoff? Deus-Stein? · How Carbon Dating is Done, Why My Calibration is Possible

Dating - the Radiocarbon Way
12 March 2010 | GNS Science

1:38 "we know how much should have been in the sample when it was alive"

For samples where the carbon age can be cross checked with historic age, and by extension, for samples with same carbon age, even without the cross check - yes.

How about the rest of the cases?

We find 25 pmC - did the sample breathe two halflives ago, or did it breathe approx. one halflife ago in an atmosphere having approx. 50 pmC?

I happen to think the latter, how would you prove me wrong?

1:46 While the equation can be simplified, the full version involves taking into account an original 100 pmC as starting point.

25 pmC only corresponds to "decay by two halflives" (0.5 * 0.5 = 0.25) if original ratio was 100 pmC.

1:56 On this part, all of my criticism of carbon dates conflicting with the Bible grants (usually, not Turin shroud) full confidence to the labs.

You say the sample has c. 25 pmC, I grant it has c. 25 pmC.

Like, charcoal from Göbekli Tepe, lowest layer carbon dated to 9600 BC, upper to 8600 BC = 11,600 to 10,600 years ago, and two halflives (which should give 25 pmC exactly) is close to the lower layer, 11460 years ago being closer to 11600 than to 10600 years ago.

As 11460 years ago is not an actual age, in Biblical chronology, I posit, what is dated like this breathed an atmosphere with less C14.

Like 42-43 pmC for lower charcoal layer and 48-49 pmC for the upper one. That gives each sample exactly as many extra years when it started out, as a sample having 42 - 49 pmC now would be dated to years ago. The equation remains the same, even if the way it is implemented in real time isn't (obviously, sth carbon dated 2000 years ago cannot be 1000 years old, since there we have good cross checks with historical dates of objects).

3:03 I am noting : the reason why one cannot carbon date things that are beyond 57 000 years old is, after that you have only 0.0009765625 "of the original amount" left, and that cannot be accurately measured.

What you mean is 0.09765625 pmC is too small amount to accurately measure.

I agree.

The thing is, when fossils not fully permineralised have been dated to 35 000 years ago, the amount remaining has obviously been above 0.09765625 pmC, since with a date of 35 000 years ago we have a remaining amount or ratio of 1.45 pmC, which can be accurately measured

8:11 Didn't you mean carbon 14 to carbon 12?

8:36 And calibration means, the original amount was not always exactly 100 pmC, it fluctuated.

For instance, on the Cambridge calibration from the nineties, made by dendro as check, the calendar years 750 to 450 BC mostly give about the carbon age 550 BC. Or, if you prefer, 2550 carbon years, or if you count backwards from 1950, 2500 carbon years.

When 750 BC carbon dates as 550 BC, we have more C14 in original ratio than 100 pmC, and when 450 BC carbon dates as 550 BC, we have less.

Back when it happened, the ratio in the atmosphere would have gone from 102.449 to 98.798 pmC.

When I claim an original ratio of 43 pmC for lower layer of Göbekli Tepe, I am doing same thing, except I use Biblical history rather than dendrochronology as check.

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