The features as a county of Chu State: chemical and metallurgical characteristics of the bronze artifacts from the Bayilu site

Twenty bronze samples from the Bayilu site (Nanyang City, Henan Province) were analyzed and compared to contemporaneous bronze artifacts. This study attempts to find out metallurgical and isotopic characteristics of the Bayilu bronzes. The results suggest the bronze artifacts are Cu-Sn-Pb alloys. Most of the bronzes were cast without secondary processing. Five samples were forged and annealed after casting, and three samples might be annealed and forged. Lead isotope data of the samples display a large range. High amount of Ag and Sb may be a trace elemental signature of the Bayilu bronzes. The major elements, the manufacture process, the lead isotope ratios, and the trace elements all have diversities. Compared to contemporary bronze artifacts, some of the samples show characteristics of the bronzes of Chu State. It indicates Shen County might be involved in the political and economic system of Chu State. It is also possible that some of the Bayilu bronzes are imported from somewhere outside Chu State. Combined with the historical background of Shen County, the diversity of the bronzes may be a signature as a border county.