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Why were the carbon 14 samples invalid? Thermochimica Acta (Volume 425 pages 189-194, by Raymond N. Rogers, Los Alamos National Laboratory, University of California)
A paper in Thermochimica Acta, is available on Elsevier BV's ScienceDirect® online information site. Elsevier is one of the world's largest providers of ethical, peer-reviewed scientific, technical and medical literature. The paper,
The abstract in Thermochimica Acta reads in part:
Preliminary estimates of the kinetics constants for the loss of vanillin from lignin indicate a much older age for the cloth than the radiocarbon analyses. The radiocarbon sampling area is uniquely coated with a yellow–brown plant gum containing dye lakes. Pyrolysis-mass-spectrometry results from the sample area coupled with microscopic and microchemical observations prove that the radiocarbon sample was not part of the original cloth of the Shroud of Turin. The radiocarbon date was thus not valid for determining the true age of the shroud.
The problem is called material intrusion. It is an uncommon problem in some carbon 14 dating exercises. For instance, in dating peat bogs, which may be very old, the samples often contain miniscule roots from newer plants that grew in the peat. Sometimes the roots, having decomposed, are indistinguishable from the older peat. What is tested might simply be a mixture of old and new material leading to erroneous results. No one expected that material intrusion might be a problem with the Shroud of Turin. But it was. By some estimates, as much as 60 percent of the Shroud of Turin sample was new thread, the result of mending in the 16th century. This is sufficient to change the date of a 1st century shroud to the medieval date range arrived at by the carbon 14 dating.
Links to the Thermochimica Acta paper may be found at Carbon 14 Botched.
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© 2004 Daniel R. Porter, Bronxville, New York
