Tracing copper mixing in the atlantic bronze age: A bayesian interpretation of lead isotope data

Abstract

This study re-examines metal provenance within the Atlantic Bronze Age (ca. 1300–700 BC). Despite clear typological links between objects found from Wales to Galicia, reconstructing the geochemical pathways of metal exchange has long been hindered, probably by the practice of recycling. Using a dataset of 337 copper-based artefacts and a robust set of lead isotope signatures from major Bronze Age copper-producing regions (Wales, southern Iberia, the Alps, Cyprus, and Tyrol), this paper applies a multivariate statistical model—a Bayesian mixing model implemented with the MixSIAR package—to estimate the probable contributions of various sources to each artefact. The results demonstrate that over 80% of the analysed artefacts are likely composed of copper from multiple sources. These mixtures are dominated by metals originating within the Atlantic complex itself, though contributions from Alpine and Cypriot sources are also detected. Temporal and regional variations suggest structured, rather than opportunistic, exchange dynamics.