Archaeometallurgical evidence from Sagzabad in regional perspective: preliminary insights into second-millennium BCE copper-based metallurgy in North-Central Iran

Abstract Late Bronze Age and Iron Age I contexts at Sagzabad have yielded copper-based artefacts and metallurgical debris, but production practices and metal supply remain poorly characterised. This study analyses a selected assemblage of twelve artefacts, seven slags fragments, and one ore fragment by optical microscopy, SEM-EDS, ICP-OES, and WDXRF; Pb-isotope analysis was undertaken for the artefacts only. Eight artefacts are compositionally unalloyed copper and four are tin bronze, although the small and unevenly distributed sample does not support a site-wide diachronic trend. Metal inclusions and slag microstructures provide evidence for metallurgical and solidification processes but do not independently identify the original ore type. Micro-area analyses of slags’ glassy matrix and associated phases provide qualitative constraints on slag formation. Pb-isotope signatures of the artefacts are heterogeneous and show limited compatibility with several Iranian ore datasets, including Veshnaveh, but the absence of isotope data for the slags and ore prevents testing cogenesis or assigning a specific source. The results therefore provide preliminary evidence for alloy variation and metallurgical activity, while raw-material provenance and the route of tin alloying remain unresolved.