Computer Applications and Quantitative Methods in Archaeology (CAA), Atlanta, 2017

Enhancing Archaeological Material Provenance Studies by manipulating Isoscapes

Till F. Sonnemann (Universiteit Leiden, Universität Bamberg), Jason Laffoon (Universiteit Leiden), Termeh Shafie (Universität Konstanz)

The availability of worldwide isotope variation data offers a new possibility to spatially display the likely origin of archaeological finds. Isoscapes, developed from these data sets, differ for each element, being dependent on particular attributes such as geology, distance from water, altitude and latitude, to name a few. The variation provides a particular opportunity, to narrow down the origin of potentially non-local material by correlating the distribution of (initially two) different isotopes. Originally applied in ecology to understand bird migration by sampling feathers, two approaches were tried to develop and test more standardized and quantitative approaches in archaeology. An exclusionary approach uses a defined range of fixed isotopic variation per location, removing any area in which one of the isotope measurements are not within the error range; and a probabilistic assignment approach, using univariate and bivariate probability density functions, to present likelihoods of provenance. First tests were conducted from results of 87Sr/86Sr and δ18O samples retrieved from modern and archaeological enamel, the hard mineralized tooth surface. The tests show both its potential and limitations. The dual-, and in future studies multi-isotope, approach in combination with continuously improving isoscape maps offer a possibility to better geo provenance archaeological samples.