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*To*: orion@mscc.huji.ac.il*Subject*: Re: orion-list Radiocarbon*From*: Tom Simms <tsimms@mailserv.nbnet.nb.ca>*Date*: Thu, 26 Aug 1999 12:55:51 AST*Reply-To*: orion@mscc.huji.ac.il

On Thu, 26 Aug 1999 13:47:54 +0200, gd@teol.ku.dk writes: [... snip ... noted ...] > There are indeed, of the nineteen Qumran texts which have > been radiocarbon dated, five which gave AMS measurements > whose two-sigma ranges are completely later than 63 BCE, > even at their earliest end, according to the most current > Seattle-Belfast calibration. That leaves fourteen samples dated earlier. If a First C CE date for the deposit is hypothesized, that argument is dead on its face. Howover, any argument for a First C BCE deposit can only be made if contamination of the samples was not taken into account or can be shown to have occurred. That argument has been made. We have no clear record of what samples were contaminated with modern oils ands what were not. Also, it appears that adequate decontamination protocols were not followed. Professor Jull suggests that for a clear answer more tests are necessary. I agree. [... snip ... noted ...] To add to the discussion, let me give a layman's view of how strongly modern contamination from oil or smoke can affect ancient meterials: Consider a fiber such as a strand of papyrus, diameter 1/1000th inch and coated with a film of smoke 1/10,000th inch thick: If a slice of the fiber is made, the area of the diameter of the fiber plus its coating is: Pi x (0.001 + 2 x 0.0001)Squared. (Remember that the film is on all of the surface of the fiber). The area of the fiber itself is: Pi x (0.001)Squared. So, the ratio of contamination to fiber is: Pi x (0.001 + 2 x 0.0001)Squared - Pi x (0.001)Squared ------------------------------------------------------ = Pi x (0.001)Squared Pi x (0.0012)Squared - Pi x (0.001)Squared ------------------------------------------ = Pi x (0.001)Squared Pi x 0.00000144 - Pi x 0.00000100 ----------------------------------- = Pi x 0.00000100 Pi may be factored out, so we have 0.00000144 - 0.00000100 0.00000044 44 ----------------------- = ---------- = --- = 44%!! 0.00000100 0.00000100 100 44% is no small figure. > Greg Doudna > Copenhagen > Instructive? See why taking contamination into account can be so important? Tom Simms http://pami.uwaterloo.ca/~reda/kings/kings.html For private reply, e-mail to Tom Simms <tsimms@mailserv.nbnet.nb.ca> ---------------------------------------------------------------- To unsubscribe from Orion, e-mail to majordomo@panda.mscc.huji.ac.il with the message: "unsubscribe Orion." For more information on the Orion Center or for Orion archives, visit our web site http://orion.mscc.huji.ac.il.

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