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

Copper provenance in Bronze Age China has long been hindered by the ternary alloying (Cu-Sn-Pb) of Shang bronzes, which masks the geochemical signatures of copper sources. Here we circumvent this problem by analyzing copper ore assemblages from two Upper Erligang period (ca. 1400 BC) bronze casting sites, Chuangxinjie School North Campus and Xiaoshuangqiao, associated with the Shang capitals at Zhengzhou. Through a multi-proxy geochemical approach combining garnet U-Pb dating and chemical composition, lead isotopes, and chalcopyrite trace elements, we systematically determine that the Shang capitals at Zhengzhou obtained copper from the Jiurui district in the Middle Yangtze Valley, ~700 km to the south. This confirms one of the earliest long-distance copper supply networks in East Asia, demonstrating that the Yangtze and Yellow River basins were linked through metal resource exchange during the formative period of Chinese civilization. The multi-proxy ore fingerprinting approach presented here also offers a transferable framework for resolving the copper provenance questions in other archaeological contexts worldwide. The origin of copper used by China’s Shang dynasty civilization (Bronze Age) has long been debated. This study uses multi-proxy ore fingerprinting to identify a 700-km copper supply network linking Middle Yangtze mines to the Shang capitals.