The evidence comes from copper-ore assemblages associated with two Upper Erligang-period bronze-casting sites dated to about 1400 BC: Chuangxinjie School North Campus and Xiaoshuangqiao. Both sites were associated with the Shang capitals at Zhengzhou. By comparing their ores with geological material from the Middle Yangtze Valley, the researchers traced the copper supplied to these casting locations to the Jiurui district.

Determining the origins of Bronze Age Chinese copper is difficult because Shang bronzes were produced as ternary copper–tin–lead alloys. Alloying masks the geochemical signature of the original ore, making finished bronze objects less reliable for straightforward provenance comparisons. The researchers instead analysed copper-ore assemblages directly, applying a multi-proxy fingerprinting method designed to identify geological links that could otherwise remain obscured by alloy composition.

The approach combined uranium–lead dating of garnet with the chemical compositions of garnet and chalcopyrite and the lead-isotope signatures of the ores. The garnet dates established the ages of individual ore assemblages, while the compositional and isotopic measurements supplied complementary evidence for matching deposits. Together, these proxies supported the conclusion that copper used at the two Zhengzhou casting sites came from Jiurui, roughly 700 kilometres away.

This is a provenance study of a defined archaeological context, not a measurement of ancient trade volume. It documents a geographically extensive supply connection between ore sources in the Middle Yangtze Valley and Shang casting sites associated with Zhengzhou in the Yellow River region. The result supports metal-resource exchange between the two basins during the Shang state’s formative period. The authors also present their multi-proxy ore-fingerprinting strategy as a potentially transferable framework for resolving copper-provenance questions in other archaeological contexts, although the reported source assignment is based on the investigated sites, period and combined mineralogical and geochemical evidence.

Subject of Research: Provenance of copper used at two Upper Erligang-period Shang casting sites near Zhengzhou

Article Title: A 700-kilometre copper supply network in Bronze Age China revealed by multi-proxy ore fingerprinting

Article References: Sun, Z., Li, J., Yang, S., Li, S., Chen, J., Li, D., Zhong, R., & Liu, S. (2026). A 700-kilometre copper supply network in Bronze Age China revealed by multi-proxy ore fingerprinting. Nature Communications. https://doi.org/10.1038/s41467-026-78864-4

Image Credits: AI Generated

DOI: 10.1038/s41467-026-78864-4

Keywords: Bronze Age China, Shang dynasty, copper provenance, ore fingerprinting, archaeometry, geochemistry, Zhengzhou, Jiurui district, Middle Yangtze Valley, metal exchange, kilometre, copper