The Characterization of Biologically Available Strontium Isotope Ratios for the Study of Prehistoric Migration

TLDR

Strontium isotope analysis of bone and tooth enamel is a promising new method for studying prehistoric migration, yet it is hampered by variable local strontium ratios and overlapping human values that obscure migrant identification. The authors use small animal bone analysis to obtain robust local strontium ratios and conservative confidence limits, demonstrating the approach with modern and prehistoric samples. Their regional data reveal substantial variability in strontium isotope values and lead them to recommend that future studies include small animal samples for comparative purposes whenever possible.

Abstract

Strontium isotope analysis of bone and tooth enamel from prehistoric human skeletons is an important new technique used to address questions regarding migration. Two problems arise in such investigations: (1) levels of strontium isotope ratios in local bedrock, soil, water, plants and animals are variable; and (2) a range of values in human bone and enamel data make it difficult to distinguish some migrants from locals. Analysis of the bones of small animals provides a robust measure of local strontium isotope ratios and a reliable, if conservative, means for determining confidence limits for distinguishing migrants. Data from various geographical areas are presented here in a discussion of variability in strontium isotope values. Examples are provided using modern and prehistoric materials. We conclude with the recommendation that studies involving strontium isotope analysis should incorporate small animal samples for comparative purposes whenever possible.