Subdivision of culture and resources: raw material transformation and cultural exchange reflected by bronze poleaxes from the Warring States sites in the Chengdu Plain

An ancient and well-developed late Shu culture was discovered in the Sichuan Basin in southwest China. For a long time, the evolution of the resource utilization of the late Shu culture has been shrouded in mystery, and it is under considerable controversy when it comes to the relationship between the late Shu culture and the Chu culture of the middle reaches of the Yangtze River. Therefore, in this paper, bronze poleaxes with characteristics of different periods, which were excavated from the Shuangyuan cemetery of the Eastern Zhou Dynasty in the Chengdu Plain, were studied by archaeological typology, portable X-ray fluorescence spectrometry (pXRF), and multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). In contrast to previous studies, this paper achieves a further distinction among the mineral sources of a very short historical period within the long history of the late Shu culture by analyzing the local bronze poleaxes. The results show that the Shu ancestors used the same kind of lead material from the early Warring States Period to the early stage of the middle Warring States Period. However, the mineral sources of the late Shu culture underwent a significant shift in the late stage of middle Warring States Period, which was closely related to the historical background of cultural exchanges between Chu culture and Shu culture. This work indicates that the exchange between Shu and Chu gradually deepened over time during the Warring States Period.