[Replying to otseng in post #1812
The TS was C-14 dated using accelerator mass spectrometry. However, using AMS, it has detected C-14 in coal deposits. This means according to AMS, coal deposits cannot be older than 40,000 years.
There is a lot more to this story as well, as you'd expect. C-14 dating is no different from other sophisticated methods and requires properly working and calibrated equipment, properly trained operators, and critically ... samples that are not contaminated and are prepared correctly. There are known scenarios where it doesn't work because of issues with the samples. One common example is the reservoir effect:
https://agupubs.onlinelibrary.wiley.com ... 17RG000588
https://heritagesciencejournal.springer ... -7445-1-24
This can impact dating of marine and freshwater specimens, as well as animals (including humans) who consumed them before death. Nuclear tests in the 1940s and 1950s also created the "bomb effect":
https://www.radiocarbon.com/carbon-dati ... carbon.htm
As for C-14 in coal, the common suspects are production of C-14 by radioactive decay of other atoms in the vicinity (expecially uranium/thorium), as well as potential production by fungal and bacteria action. Like the reservoir effect, these would violate the basic assumption in C-14 dating that the sample has remained in equilibrium with the environment continuously so that when it was living (as a plant, or animal, or something made from them) it consumed carbon compounds that were metabolized in the body and as a result the distribution of carbon isotopes in the living organism should match those of the environment. At death, there is no more intake of food, water, air, etc. so the C-14 present at death decays according to is half-life while C-12 concentrations remain stable.
I don't think the C-14 in coal issue is a strong argument against AMS and the dating process for the TS samples. AMS has proved reliable in far too many other cases to discredit it due to an effect that may result in more C-14 in the sample that is independent of the AMS process (ie. AMS measures C-14 correctly, but there is simply more of it in cases where it is produced outside of the basic assumption above for C-14 dating, such as the marine reservoir effect).
To me, a bigger concern might be the fact that so few TS samples were tested, and all from a single "patch" about 3" x 1" in size. The fact that three indpendent labs all obtained similar results is certainly supportive of the results, but I would have thought more samples from different locations would have been taken if they really wanted to get the best results and put the issue to rest. Using one example where AMS (or C-14 dating in general) produces anamolous results in coal does not outweigh the much higher rate of "normal" results the method has produced. If one wanted to cast doubt on the C-14 dating, it seems to me the target should be not the C-14 dating process itseld, but in the limited area that was tested (although presumably this patch was chosen in the belief that it best represented the original shround and not a later repair effort, obviously).