Spatial Approaches to Assignment

Abstract

This chapter introduces the spatial approaches which are used to determine the likely geographic origins of humans and animals and which in turn are used to understand mobility and migration. Two approaches are outlined -the first based on the calculation of residuals, and the second based on Bayesian statistics and maximum likelihood estimation. Both approaches compare the observed isotope measurement for an archaeological sample to the expected isotope measurement from baseline data for the area of interest. These approaches are applied to case studies from Annaghmare in Northern Ireland and Duggleby Howe on the Yorkshire Wolds. The case studies highlight the uncertainty implicit within the process of assigning an individual to a geographic region and the importance of using baseline data which adequately accounts for all of the factors that influence the spatial variation of the measured isotope tracer.

Strontium (87Sr/86Sr) mapping: A critical review of methods and approaches

“…The two main methods of interpreting strontium results, the calculation of residuals (or basic comparison of biosphere and sample values) and the use of Bayesian statistics, are outlined and illustrated in Pouncett (2020). Either method is generally more straightforward when provenancing the source that was used to build the isoscape, such as when wines of various origins are compared against wines of known origins (Durante et al 2015).…”