Bioavailable strontium isotope baseline for the Novotemirskiy Bronze Age mine

To assess the mobility and provenance of ancient populations, it is necessary to compare their 87Sr/86Sr isotopic ratios with the local bioavailable strontium baseline (background), characteristic of each specific location or potential provenance region of an individual or artifact. Its definition requires a comprehensive approach to the analysis of heterogeneous samples («proxies») characterizing the ecosystem of the archaeological site under study, the identification of the most suitable proxies, as well as the unification and standardization of the sampling and analytic protocols. A pilot study is presented devoted the definition of the local range of bioavailable strontium by the example of the Novotemirskiy Bronze Age mine (Southern Urals). 87Sr/86Sr isotope ratios were determined in surface and underground water, bedrock (serpentinite), clay from the mine wall, and steppe polecat’s bone, as well as in grass and a bivalve shell from the lake. The lowest range of strontium isotope ratios relative to each other is characteristic of surface and groundwater, shell and grass, which allows them to be used to determine the combined baseline of bioavailable strontium. Multi-proxy (surface and underground water, grass and a bivalve shell) local bioavailable strontium baseline for the Novotemirskiy ancient mine (Southern Urals) is 0,7096 ± 0,0003 (2σ, n = 5).