On Wed, 26 Mar 2008 08:08:36 -0000, "Paul Nutteing (valid email
address in post script )" wrote:
>So how do they use C14 dating with such confidence, for recent carbonaceious
>material?
>http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2008/03/25/njersey225.x
>ml
>"Stories of abuse - physical, .ual and psychological - as well as claims
>of solitary confinement have continued to emerge since a child's skull was
>discovered at the home in February.
>
>Mr Harper said carbon dating was still being carried out on the skull, but
>he added that it does not date back to earlier than the 1920s."
>
>AFAIK C12/14 dating is very poor when you go outside of range 10 halflives
>to 1/10 half life of 5,700 years or so.
>So late mediaeval is about the most recent with any useful confidence,
>perhaps pushed to 200 years (19C) with modern techniques/ calibration
>curves.
There may of course be significant inaccuracies in the media reports
as to exactly what is being done to what and how conclusions are
arrived at.
I should think it likely that the "no later than 1920s" conclusion was
reached by examining tooth fillings rather than carbon dating - which
as you have stated is not the correct tool to use for timescales of
that small magnitude.
--
Cynic
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