Did China Import Metals from Africa in the Bronze Age?

Abstract

The origins of the copper, tin and lead for China's rich Bronze Age cultures are a major topic in archaeological research, with significant contributions being made by archaeological fieldwork, archaeometallurgical investigations and geochemical considerations. Here, we investigate a recent claim that the greater part of the Shang-period metalwork was made using metals from Africa, imported together with the necessary know-how to produce tin bronze. A brief review of the current status of lead isotopic study on Shang-period bronze artefacts is provided first, clarifying a few key issues involved in this discussion. It is then shown that there is no archaeological or isotopic basis for bulk metal transfer between Africa and China during the Shang period, and that the copper and lead in Shang bronze with a strongly radiogenic signature is not likely to be from Africa. We call for collaborative interdisciplinary research to address the vexing question of the Shang period's metal sources, focusing on smelting sites in geologically defined potential source regions and casting workshops identified at a number of Shang settlements. KEYWORDS: LEAD ISOTOPES, HIGHLY RADIOGENIC LEAD, SHANG BRONZE, PROVENANCE INTRODUCTIONMost major Bronze Age civilizations developed in the catchments of large rivers that were sustaining a high population density through intensive agriculture. These areas, however, are almost always devoid of mineral resources, which are typically exposed only in mountainous areas, remote from the centres of agricultural civilization. Thus, these centres were dependent on distant areas to provide their strategically important metals, primarily copper, tin and gold, but also lead and silver. Substantive research has identified major copper sources for Egypt, Mesopotamia and Chen et al. 2009Chen et al. , 2016Pollard et al. 2017). Among these, Shang-period bronzes dated between the 16th and 11th centuries BCE stand out due to their highly distinctive isotopic and chemical compositions. The identification of the geological source(s) of this metal is a long-standing issue in Chinese archaeology, which has attracted considerable research interest from many scholars of various disciplinary backgrounds. A recent paper by Sun et al. (2016) is a new, but unconvincing, attempt to answer this question. It not only claims that 'the Yin-Shang people may have learned bronze technology elsewhere and brought it to China ' (Sun et al. 2016, 5), but it also concludes that 'both the Yin-Shang and the Sanxingdui bronzes were obtained in Africa, bearing the highly radiogenic lead isotopic signatures of Africa's Archean cratons. Alternatively, some ancient people might have come to China from Africa, carrying tin and/or bronzes with them' (Sun et al. 2016, 6). These hypotheses are undoubtedly bold and eye-catching, but unfortunately are also fundamentally flawed. In this paper, we offer a brief summary of currently available research on highly radiogenic lead found in ancient Shang bronzes, clarifying a few key issues that were m...

Comment on ‘Did China Import Metals from Africa in the Bronze Age?’

“…Liu et al . () claim our conclusion that ‘Yin‐Shang bronze with highly radiogenic Pb isotopes may came from Africa’ (Sun et al . ) is ‘fundamentally flawed’.…”

Lead isotope and metal source of Shang bronzes: a response to Sun et al.’s comments

“…The seventh paragraph in Sun et al .’s comments continues to mislead readers in the following statement: ‘The only difference is that we proposed Yin‐Shang bronzes may come from Africa, whereas three out of the four papers cited by Liu et al () proposed an origin based on the Eurasian Steppe.’ It is alarming to see that Sun and collaborators know so little about Chinese prehistory that they failed to realize that these metallurgies are of quite different ages. What we discussed in our paper is the origin of early copper and bronze metallurgy—dated to the early second millennium bce —that has shown a strong connection with the Eurasian Steppe, while the focus of Sun et al .…”

“…, Liu et al . ). This suggests that the copper and lead sources of these bronzes both have similar (and highly radiogenic) lead isotope ratios.…”

“…We have never claimed that the Shang people had no knowledge of other metals, but stated clearly ‘that the source of the highly radiogenic lead in the alloy is indeed a copper ore with variable lead content’ (Liu et al . , 107). As noted in our paper, Shang artefacts with highly radiogenic lead isotope ratios are known to show a wide range of lead contents, and the scatter plot of 206 Pb/ 204 Pb‐Pb reveals no correlation between their lead isotope ratios and lead contents (Meyers et al .…”

“…The southern African copper and bronze samples that are highly radiogenic ( 206 Pb/ 204 Pb > 20) do not match the Shang bronzes. Sources: Data from Jin ( ), Molofsky et al ( ), Sun et al ( ) and Liu et al ( ) . [Colour figure can be viewed at wileyonlinelibrary.com]…”