Scientific Analysis on Casting Materials from Yaoheyuan, Ningxia: The approach of understanding technological choices in remoted workshop

    Ancient Chinese bronze casting industry primarily relied on Piece-mould Casting Technology, stone moulds and lost wax method were rarely used. This tradition is different from other ancient bronze cultures. The newly discovered site Yaoheyuan姚河塬, located in Pengyang, Ningxia province, represents the westernmost territory of the Western Zhou (1046-771 BCE) dominion. This site was identified by scholars as the capital of state Huo获, and was active throughout the Western Zhou period. Over 1000 casting relics were found at the site, mainly tool, horse ware, and weapon moulds. This study combined petrography, X-CT, SEM, and XRD analysis, conducted a preliminary discussion on 25 casting samples, 2 ceramics, 7 processed raw materials, and 55 soil samples from the workshop unearthed in this site.

    Firstly, some moulds were made directly with unprocessed soil, this is different from former research. Considering the existence of processed raw materials, craftsmen might have followed 2 different traditions and simplified the levigating procedure. Secondly, some dried or heated raw materials were mixed with wet ones for making moulds. The patterns were carved out and used directly for casting. This suggests that some models found earlier in other sites were possibly moulds. Thirdly, the technology of layering and coating was selectively applied, this step was omitted for moulds that didn’t require a smooth surface. Last, traces of using core box or mould for moulds were found, similar signs could also be seen at sites from Central Plain.

    To sum it up, Yaoheyuan site could cast bronzes and their technique comes from central plain of China (Anyang probably). Zhou dynasty’s controlling power might be shown with controlling the types of bronzes they could make. The craftsmen might adjust the mould-making technology with soil sources.