Assumptions baked into the VMS carbon dating

[oshfdk]

Sure, but to combine those ranges into a smaller range by assuming they are the same object is not correct. If these were 4 samples from 1 folio, I would totally agree. But it's not. The individual results have FAR larger ranges, and those ranges are falsely shortened based on assumptions that aren't true.

The individual results do not have far larger ranges in the actual metric that was measured (y axis). All these samples are grouped together quite well, and I think the conclusions in the paper are the right ones - this strongly suggests a single object with a single narrow range of years. Suppose, the calibration curve was monotonous throughout this period, and we get the following results for the time period:

   

Would you rather think that the object was created somewhere in the yellow range, which would be consistent with all 4 measurements, or would you say that there likely were two different time ranges hidden there?

But this above is exactly what the actual values measured in the lab show, before it's artificially split in a bimodal distribution by the double-humped calibration curve. These curves above are what we should use to assess whether it's a single object or not, and not the computed time range.

Also, consider the radical shift in the curve of f68 depending on which chemical processing was used, I've made the other 3 curves transparent in the image below, the two remaining curves are two versions of f68, the results for the very same sample, just differently processed. Basically, f68 lies on the opposite sides of the spectrum of all the samples depending on how much of the possible contamination with modern carbon was removed. Which means the error potentially produced by inconsistencies of the source material is nearly as high as the observed range of results.

   

I don't think it makes sense to pay a lot of attention to this bimodal distribution of dates, it's not very likely actual 50 years passed between one folio and the other.