New scientific analyses reveal mixing of copper sources in the early Iron Age metal production at Ili, western China

Abstract

The crucial role that Xinjiang played in cultural communication across the Eurasian steppe in prehistory is evidenced by the large number of copper-based objects that represent the early metallurgical technologies found across this region. Our research adds new chemical and isotopic analyses of 44 copper-based objects dated to the early Iron Age of Ili in Xinjiang, western China. As noted in a number of publications, tin bronze and arsenic copper/bronze were the dominant alloying types across Xinjiang during the second and first millennium BC, whereas some specific types of objects such as cauldrons are often made from pure copper. The western Tianshan Mountain, including the well-known mining site Nulasai, is the most likely copper source for the Ili metalworking. Meanwhile, a combination of lead isotopes, lead concentrations and trace elemental data reveals new evidence for the mixing and recycling of different sources of copper.

Separation or integration? Further insights from a study on chemical datasets of ancient bronze drums from South and Southeast Guangxi, China

“…The Oxford Group Bray and Pollard conducted a series of studies on the presence/absence classification system based on the above four elements [30][31][32] and classified them into 16 copper groups based on the content of each element: > 0.1% (presence), or < 0.1% (absent), arguing that this approach presents the full potential of the chemical space that these elements afford [33]. Moreover, it is shown to be equally applicable to any set of analytical data for copper alloys regardless of region and time period [34][35][36][37][38][39][40]. Characterization, rather than provenance of archaeological alloys, is the most important reason for the choice of analytical method in our paper, although there seems to be much controversy over the choice of elements and their fixed threshold of 0.1 wt.% [16,18].…”

Research on copper production of the Bohai Kingdom in Northeast China

“…The isotope investigation was the most popular for the provenance research [27], but in this study, the embraced prill in the processing slag has reflected the remelting and remixing/recycling of different copper raw materials. This scenario was not commonly supported by archaeological discoveries in the bronze age but could not be continually neglected in the iron age [28]. And what is noteworthy is that some of the gilt artefacts contained a pretty high level of silver (lower right Fig.…”

Separation or Integration? Further Insights from a Study of Chemical Datasets on Ancient Bronze Drums from South and Southeast Guangxi, China

“…6c,d). Since lead concentration is a major concern when using lead isotope analysis to investigate the provenance of copper-based metals in antiquity [24], this close correlation between the two types can be mathematically expressed and proved by plotting lead isotope data against 1/Pb(%) [25] (Liu et al, 2022). In Fig.…”