From: Mccarrick Alan D CRPH (MccarrickAD@nswccd.navy.mil)
Date: Fri Oct 03 2003 - 10:38:08 EDT
I don't think anyone directly cleared this up:
>Allen wrote: The way I understand the graph is that it displays the
> amount of C14 in some coal samples as a percent of modern carbon
>(meaning C12) . So 2 samples (as indicated on the graph) had the
> C14/C12 ratio of 0.1 percent (0.1%). Or 1 C14 atoms per 1000 C12
> atoms -- 1 C14 / 1000 C12. That seems pretty straight forward to me.
What is meant in the article "pmc" or "percent modern carbon" is the ratio of the C14/C12 ratio found in the sample to the C14/C12 ratio found in a "modern" sample. This is almost explained on page 9 of the RATE article "Measurable 14C in Fossilized Organic Materials..." The primary ratio of C14/C12 starts out as 10-12 for modern materials and drops from there. So a sample with 1 pmc would actually have 10-14 C14/C12 in it. Reporting pmc creates larger numbers easier to work with or think about.
The whole article is interesting and concluded that the persistent problem of residual C14 in "C14 dead" materials. The authors conclude that the evidence points to a young earth because of the presence of C14, but assumes "miracles" to explain old dates by U/Pb, K/Ar...
Al McCarrick
-----Original Message-----
From: allenroy [mailto:allenroy@peoplepc.com]
Sent: Wednesday, October 01, 2003 5:16 PM
To: John W Burgeson
Cc: asa@calvin.edu
Subject: Re: RATE
John W Burgeson wrote:
> Page iii of that monograph has a graphic which renames C14 as "modern
> carbon"
The way I understand the graph is that it displays the amount of C14 in some
coal samples as a percent of modern carbon (meaning C12) . So 2 samples (as
indicated on the graph) had the C14/C12 ratio of 0.1 percent (0.1%). Or 1 C14
atoms per 1000 C12 atoms -- 1 C14 / 1000 C12. That seems pretty straight
forward to me.
Allen
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