A04_P01

“Here we go again”: the inspection of collagen extraction protocols and why compound specific radiocarbon dating matters

Devièse T¹

¹Aix Marseille University, Aix en Provence, France

The radiocarbon dating of archaeological bones is widely used across various fields of research, most notably by palaeontologists, palaeoecologists, archaeologists and geneticists. The radiocarbon dates obtained on fossils allow scientists to reconstruct ancient ecosystems and the rates of faunal change in these communities as well as human occupations. Reliable and accurate dating is therefore hugely important. However, there are major challenges when radiocarbon dating bone specimens over 30,000 years old and there is considerable uncertainty over some of the published data.

The method currently used by most radiocarbon laboratories to date archaeological bones was developed in the 1970s and consists of a succession of chemical treatments designed to extract and purify collagen before measurement on the Accelerator Mass Spectrometer. However, for radiocarbon results to be reliable, samples must be totally free of contamination, and this is not always possible, particularly when the contaminants are cross-linked to the collagen. An alternative is to use the so-called “compound specific dating approach”, focusing on a single amino acid, hydroxyproline (HYP) within the bone collagen. Extracting and dating HYP results in excellent levels of reliability that no other method can provide.

After a description of the method’s principle, this presentation will show, with several case studies, that many dates published in the literature and obtained after less robust pretreatments can be highly inaccurate. Such errors can then lead to incorrect interpretations of dispersal and rates of change in the archaeological, climatic, and evolutionary records, as the dates are the foundation of all these models.