How to test the dating system

11 Oct 2021

Revisionists have issues with C14 as it contradicts their ideas on revising downwards, ancient history. In the November issue of Current Archaeology 380, we have a one page piece under the title of Science Notes [a regular feature on a variety of subjects but usually from a science angle]. The idea this time is combining C14 dating with aDNA data. It promises to yield some interesting results if it ever becomes operational. Will the radiocarbon people allow the genetic types to interfere with their carefully constructed calibration curve?

What will happen when it confronts the Hallstatt Plateau, where archaeologists struggle to get a definite date. Or any plateau event, come to that. If one suspects, as some do, that Egyptian chronology was used as a baseline for the calibration curve, might this all come to light if genetics are integrated into the system? The benefits of ancient DNA and radiocarbon dating are undeniable, that is a clear statement of fact. Ancient aDNA provides information about genetic relationships, population movements, and health etc. Radiocarbon is a tool for dating organic remains. New research by Jakob Sedig, a member of the David Reich team at Harvard, is looking at how aDNA might be useful in helping refine C14 dating methodology - see https://doi.org/10.1016/j.pnas.2021.105452 ... the premise here being that humans only live for so long so if two individuals are identified as closely related genetically there can only be so many years between the dates of death [as they are known primarily from burials]. This can obviously be used to refine C14 dates. The team, therefore, set out to test the hypothesis and examined genealogical data and found that the mean value between parent and child was 28.84 years etc. The team applied this to genetically related individuals from the Reich Laboratory database of 5700 published ancient genomes [which are derived from across the globe]. Within that database there were 837 individuals that have at least one identified relative. 203 of these have been C14 dated. They homed in on samples from two Bell Beaker mounds in Britain - at Amesbury and Porton Down. Two individuals, one from each site, were found to share 50% of their autosomal genoma but had different mitochondrial DNA haplotypes, suggesting they were father and daughter. Their previous C14 dates were 2480-2280and 2140-1940 cal BC, respectively - a biological impossibility. The older was re-dated by the latest C14 methodology with a revised date of 2200-2030 for the father which therefore fell in line with the date for the daughter.

Why was the earlier C14 date so wide of the mark. It depends on how long ago the dating took place and which variety of IntCal was involved. Anyway, the fact that aDNA can lead to more accurate dating is all that matters here, and potentially, it could open a can of worms. Obviously, archaeologists are working in a framework in which there are a lot of dates taken yonks ago when the methodology was not as sophisticated as it is now. Clarity can in some ways be gained by using aDNA - but of course, there are only a limited number of fathers and daughters on the genome database.