Mediterranean Late Bronze Age copper ingots: A new lead isotope-based synthesis

Within the dynamic exchange networks of the Mediterranean Late Bronze Age, copper ingots are central to reconstructing the scale, organization, and intensity of economic and cultural contact. Yet, whether Late Bronze Age copper ingots derived from a single copper source or were mixed among sources has remained largely unresolved, obscuring their provenance. This study re-examines the extensive corpus of lead isotope data from 752 copper ingots recovered across the Central and Eastern Mediterranean to reconstruct Late Bronze Age raw copper circulation. To interpret this corpus, we introduce a five-step provenance protocol, tailored to Mediterranean copper ores, that groups ingots by their alignment along Stacey-Kramers chords. Each group is then matched to the isotopic and Pb values of relevant ore regions, while ingots deviating from the chords are flagged as candidates for mixing. Our findings reinforce the position that unmixed Cypriot raw copper dominated Mediterranean markets during the period and also circulated alongside minor quantities of copper from other sources. Significantly, only a small percentage of ingots exhibit evidence for mixing, suggesting that the majority of known ingots are products of primary smelting activities. This synthesis helps to resolve long-standing debates regarding Bronze Age metallurgical practices and provides a robust framework for interpreting future copper-based provenance data.