A fragment of metallurgical waste buried with a young craftsman at Castillo de Huarmey in Peru may have originated hundreds of kilometres away in present-day Bolivia, according to research reported by HeritageDaily Archaeology. The evidence suggests that pre-Inca communities maintained long-distance networks for moving metal and potentially sharing technical expertise.
Castillo de Huarmey was a major Wari necropolis on Peru’s northern coast more than 1,300 years ago. Excavations at the site have uncovered the graves of specialised craftspeople, including the burial of a man estimated to have been about 20 years old. More than a dozen bronze tools and objects accompanied him, among them a saw, axe, knives and chisels.
Researchers also found a small dark fragment in his hand. It was identified as speiss or matte, a by-product formed during the smelting of metal ores. Although the piece was visually plain, its composition offered clues about the geological source of the material used by the community.
Scientists from institutions including the University of Warsaw, the University of Silesia, the Polish Academy of Sciences, the University of Florida and Juniata College examined the fragment using lead-isotope analysis. Because ore deposits have distinctive ratios of naturally occurring lead isotopes, those ratios can be compared with geological materials and archaeological objects from across the Andes.
Several possible sources emerged during the comparison, including locations in southern Peru and Bolivia. When the isotope findings were considered alongside chemical and mineralogical evidence, however, the Pulacayo region of Bolivia became the most likely origin. Earlier analyses of other metal objects from Castillo de Huarmey had also indicated connections with that area.
The researchers suggest that communities may have processed ore near its source before transporting it, since moving large quantities of heavy ore would have been inefficient. The material could have reached the Peruvian site in partially processed form, as semi-finished products or as completed objects intended for remelting. Llama caravans may have carried some shipments through the Andes, while maritime transport is also a possibility raised by the research.
The fragment itself may have been produced during metalworking at Castillo de Huarmey. Researchers say it could have served as a reference for quality or technique, or represented the deceased man’s profession and status. That interpretation remains uncertain: no furnaces or substantial accumulations of metallurgical waste have yet been found at the site, so there is no definitive evidence that primary smelting occurred there.
The results nevertheless add to evidence for economic and technological connections spanning the Andes centuries before the rise of the Inca Empire.
