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Re: Ink and paper analysis?
John Bush comments on what Jim Reeds said: >>Jim Reeds wrote:
>Dating of parchment, for instance, cannot be reliably done by C-14
analysis, someone told us early on.< - Yes, I recall reading this in
disbelief on someone's VMS page. Has anyone followed up on this with an
expert, or is it just someone's opinion?<<
Carbon 14 is a naturally radioactive form of carbon with a half life of
around 5,000 years. Dating of carbon-containing artifacts is accomplished by
measuring the amount of carbon 14 present in a sample.
Measurement used to be done by counting radioactive decay events. More modern
methods employ mass spectrometry, which sorts out isotopes of different
atomic weights (99% stable carbon 12, 1% stable carbon 13, and a trace of
radioactive carbon 14) - so that you don't have to wait for the decay event.
Mass spectrometry is more precise than decay counting, and the sample size
required is a great deal smaller. The infamous Shroud of Turin, for example,
has been dated by this newer method.
Even with this refinement, the precision and accuracy of carbon 14 dating
would not be good enough to be likely to yield useful information,
particularly because there was a good bit of fluctuation in carbon 14
production during the time period we're interested in (these fluctuations are
the result of variations in solar radiation, which produces carbon 14 from
nitrogen 14 in the upper atmosphere).