Analyzing Radiocarbon Reservoir Offsets through Stable Nitrogen Isotopes and Bayesian Modeling: A Case Study Using Paired Human and Faunal Remains from the Cis-Baikal Region, Siberia

Abstract

Dietary offsets in radiocarbon dates are becoming increasingly interesting to researchers, not only because of their impact on the reliability of chronologies but also because of the possibilities for extracting further dietary information from the ¹⁴C data itself.  This is the case with the cemeteries of the Cis-Baikal region being studied as part of the international Baikal-Hokkaido Archaeology Project set up to examine hunter-gatherer cultural dynamics in eastern Asia. Fortunately, to control for a freshwater reservoir offset, we were able to obtain a number of paired terrestrial herbivore and human material for ¹⁴C dating.  This article tests the correspondence between stable isotope evidence and the offsets seen in ¹⁴C values and the implications for the analysis of the ¹⁴C measurements as “chronometric dates.”  This is an unusually well documented example of freshwater reservoir offsets, providing an ideal case study to test different approaches to analysing such offset information.  Here, we compare a purely Bayesian approach with the more frequently applied linear regression analysis.

DOI: 10.2458/56.17160