Sequential multi-isotope sampling through a Bos taurus tooth from Stonehenge, to assess comparative sources and incorporation times of strontium and lead

Abstract

The aim of this paper is to use the sequential nature of enamel deposition in hypsodont teeth to study the relationship, in time and source, of strontium and lead isotopes to better understand the use of this pairing of elements for studies of movement and migration. Carbon and oxygen isotope analysis were included to place the data in their seasonal and dietary context. The study was undertaken on an M3 from a Neolithic cattle tooth excavated from Stonehenge. The animal was female based on peptide analysis. The tooth records c. six months of enamel deposition from winter to summer, based on δ¹⁸O_carbVSMOW compositions, and changes in δ¹³C_carbVSMOW that reflect a shift from forest to grassland food sources. ⁸⁷Sr/⁸⁶Sr varies from a winter value of 0.7144 to 0.7110 in summer. Lead concentrations and isotope composition shows peaks and troughs which contrast with the unidirectional change in the ⁸⁷Sr/⁸⁶Sr. We suggest that whereas the Sr is wholly derived from dietary sources the Pb represents a balance between diet and skeletal reservoirs, the latter being scavenged during a time of metabolic stress attributed to calving and lactation. It is thus important to consider skeletal reservoirs as a source of Pb when using this element to track movement and migration. This study demonstrates the value of using the complementary isotope systems of lead and strontium in tandem, but also highlights that their integration must be undertaken with caution and with full consideration of alternative drivers of variation.