P_01

Radiocarbon Dating of Historic Sites in the Age of Single-year Calibration

Bayliss A¹, Marshall P¹

¹Historic England, London, United Kingdom

IntCal20 marks the start of the next era of radiocarbon dating, as high-precision single-year calibration is extended across the radiocarbon timescale. Increasingly precise ¹⁴C measurements on single-entity samples produced by Accelerator Mass Spectrometry, combined with archaeological and historical prior information using Bayesian chronological modelling, means that this new high-resolution calibration can be used to construct accurate chronologies that are precise to within a decade or two for many kinds of sites.

Producing such chronologies demands much of laboratory accuracy, and much of the kinds of samples and prior information provided by archaeologists. We are at the start of a journey to discover how such chronologies can be produced in practice. What kinds of quality assurance data do laboratories need to provide to ensure the necessary measurement accuracy? What kinds of samples should archaeologists submit for dating, and how do they construct the sampling strategies needed to make the most of the opportunities provided by single-year calibration? What kinds of sites and problems will produce substantively more precise and reliable chronologies using single-year calibration, and what kinds of sites will not? How do we weave those sites that do not into our wider narratives?

This paper provides some initial thoughts on these issues illustrated by a range of recent case studies.