Radiocarbon dating error margin
Most mineral materials, including the constituents of pottery, have the property of thermoluminescence (TL), where part of the energy from radioactive decay in and around the mineral is stored (in the form of trapped electrons) and later released as light upon strong heating (as the electrons are detrapped and combine with lattice ions).
It is an absolute dating method, and does not depend on comparison with similar objects (as does obsidian hydration dating, for example).
This is a naturally occuring isotope that is found in bones among other things). I think that a old creationist canard should have been explicitly mentioned: You do not expect accurate C-14 dates from carbon samples that come from under the ocean.
Sr-90 can be used to date bones (not fossils) but the increase in Sr-90 levels have to be accounted for. You can't date jack with C14 if it's younger than 500 years. If your saying that all C14 dates are correct for 1950, not 2000, that's true, but again, the difference is too small to count. (Like the "living 20,000 year old" molluscs that creationists keep bringing up.
Reviewing recent Shroud literature of all persuasions, I find little awareness of the limitations of the C-14 method, an urge to "date first and ask questions later," and a general disregard for the close collaboration between field and laboratory personnel which is the ideal in archaeometric projects.
Regarding the Shroud, consultations should take place among archeologists, historians, conservationists, cellulose chemists and of course radiocarbon scientists in order to formulate a specific C-14 sampling and dating procedure.
The thermoluminescence technique is the only physical means of determining the absolute age of pottery presently available.
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Note that the margin of error in dating the Shourd of T is plus or minus 65 years, and we're dating back almost 700 years ago. [Edited by CKDext Havn on at AM]The isotopal change that occurred with the advent of A-bomb testing is Strontium-90.In this paper I shall examine the issue of the reliability of C-14 testing to produce an "absolute date" on the linen sheet known as the Holy Shroud of Turin and believed by some to be the gravecloth of Christ.I have previously (Meacham 1983) treated the question of the Shroud's authenticity at length and shall confine my remarks here to the applicability and ultimate reliability of radiocarbon as an "authenticity test" of the relic.As I shall endeavor to demonstrate below, the radiocarbon measurement of the Shroud is a complex issue, and the inclusion of all relevant expertise is highly important.In May, 1985, I submitted such a proposal to Cardinal Ballestrero, Archbishop of Turin and official custodian of the relic, in the hope that the ecclesiastical authorities would consider appointing a scientific panel to plan and implement a C14 testing program.