Constellations of practice in copper ingots from Zambia and northern Zimbabwe, cal. AD 500–1700

ABSTRACT

Rectangular, fishtail and croisette copper ingots have been found in many locations in Central and southern Africa where excavated samples date to between the fifth and eighteenth centuries cal. AD. For more than fifty years, scholars have debated whether these ingots were all made in the Central African Copperbelt, where there are many finds of matching moulds, or if moulds found in Zimbabwe show that copies were produced locally. Lead isotopic and chemical analyses have recently confirmed that the Copperbelt supplied copper ingots to both southern Congo-Kinshasa and the Zimbabwe Plateau between the ninth and eighteenth centuries, but that one HXR ingot can tentatively be sourced to the Magondi Belt copper deposits in northern Zimbabwe. We expand this discussion here by linking ingot chemistry and isotopic provenance with distribution patterns and ingot morphologies. The combined evidence suggests that groups making Luangwa Tradition pottery were responsible for transporting HIH and HXR ingots, and the technological styles for making them, far to the south of the Copperbelt. These croisette ingots link constellations of practice in the Copperbelt and Zimbabwe, possibly through the movement of specialised traders and metalworkers. We identify some of the individuals buried at Ingombe Ilede and Chumnungwa as possible examples of these specialists.

RÉSUMÉ

Des lingots de cuivre de forme rectangulaire, en queue de poisson ou en croix ont été découverts en de nombreux endroits d'Afrique centrale et australe, et les échantillons issus de fouilles datent du cinquième au dix-huitième siècle après J.-C. Depuis plus de cinquante ans, les chercheurs se demandent si ces lingots ont tous été fabriqués dans le ‘Copperbelt’ d’Afrique centrale, où l’on a trouvé de nombreux moules correspondants, ou si les moules trouvés au Zimbabwe indiquent que des copies furent produites localement. Des analyses isotopiques du plomb et des analyses chimiques ont récemment confirmé que le Copperbelt a fourni des lingots de cuivre à la fois au sud du Congo-Kinshasa et dans le plateau du Zimbabwe entre le neuvième et le dix-huitième siècle, mais que l’un des lingots HXR peut être provisoirement attribué aux gisements de cuivre de la Ceinture de Magondi, dans le nord du Zimbabwe. Nous élargissons cette discussion en établissant un lien entre la chimie et la provenance isotopique des lingots, d’une part, et les schémas de distribution et les morphologies des lingots, d’autre part. L’ensemble de ces éléments suggère que les groupes qui fabriquaient des poteries de la tradition Luangwa étaient responsables du transport des lingots HIH et HXR, ainsi que des styles technologiques utilisés pour les fabriquer, loin au sud de la Copperbelt. Ces lingots croisettes relient des constellations de pratiques dans le Copperbelt et au Zimbabwe, peut-être par le biais du mouvement de commerçants et de métallurgistes spécialisés. Nous identifions certains des individus enterrés à Ingombe Ilede et à Chumnungwa comme de possibles représentants de ces spécialistes.

KEYWORDS:

• croisette ingots
• ingot moulds
• technological style
• Copperbelt
• Zimbabwe
• Zambia

Acknowledgments

We thank Dr George Mudenda, Director of the Livingstone Museum, Zambia, and Dr Godfrey Mahachi (Executive Director) and Mr Godhi Bvocho (Regional Director) of the Museum of Human Sciences, Zimbabwe, for granting us access to their collections. We are grateful for the dedicated work of the staffs of the Livingstone Museum and of the Museum of Human Sciences to preserve these archaeological collections for researchers, especially Rutendo Komborayi, Nyararai Mundopa, Kelvin Mukabeta and Kundishora Chipunza for their assistance with our work on them. The National Heritage Conservation Committee in Zambia and the National Museums and Monuments Board of Zimbabwe are thanked for granting us permission to export small sub-samples of copper objects for analysis. At the University of Arizona we thank Dr Joaquin Ruiz for access to his laboratory and Drs Mark Baker and Jason Kirk for training and assistance in running the MC-ICP-MS. Dr Mary Kay Amistadi was invaluable in measuring the trace element concentrations. We thank ARMI-MBH Analytical for providing materials to evaluate our dissolution procedure, and Dr Stephanie Martin for her work in ArcGis to produce the map figures. We also thank Dr Terry Childs for commenting on an early version of this manuscript and the two anonymous reviewers for their time and comments.

Notes

1 Although rectangular and fishtail ingots are included as the ‘Ia’ category in de Maret’s (1995) croisette typology, they are not croisette ingots as they are not cross-shaped. We maintain the distinction between these ingot types in this paper.

2 The model of ‘eastern’ and ‘western’ stream migrations into southern Africa is currently being re-evaluated from a linguistic standpoint. The various population movements into southern Africa are now labeled ‘Central-Western’, ‘West-Western’, ‘South-Western’, and ‘Eastern’ following Grollemund et al. (2015). We currently await archaeological evaluation of this model, and thus keep the ‘eastern’ and ‘western’ stream classification.

3 We were unable to inspect this object personally. Descriptions by Bent (1896) and Caton-Thompson (1931) describe only one face.

4 At Chumnungwa, an individual was found buried between the boulder in the main wall and the 12-foot (∼3.65-m) wall on the eastern end of the enclosure. This person was buried with gold ornaments (gold bangles and large gold beads), smelted gold, an HIH copper ingot, a pair of double iron bells, a ‘rosette’ of beaten gold and a large soapstone bowl (Hall and Neal 1902: 229).

Additional information

Notes on contributors

Jay Stephens

Jay Stephens is a post-doctoral research fellow at the University of Missouri Research Reactor Center (MURR) and received his PhD in 2022 from the University of Arizona. His research applies geochemical and archaeometric methods to infer the provenance of inorganic archaeological materials and to reconstruct the technologies employed during their production. He has worked on projects in southern Africa, Central Asia, Greece, Italy and the southwestern United States.

David Killick

David Killick retired in 2023 as Professor of Anthropology at the University of Arizona in Tucson, where he had taught since 1991. He studies the history of mining and metallurgy and also employs petrography and heavy isotopes to infer the provenance of inorganic materials such as non-ferrous metals, pottery, turquoise and lead minerals. He has worked on projects in South Africa, Botswana, Malawi, Cameroon, Senegal, Madagascar and Kenya, as well as in Peru, the northeastern and southwestern United States and New Caledonia.

Shadreck Chirikure

Shadreck Chirikure is Edward Hall Professor of Archaeological Science and British Academy Global Professor in the School of Archaeology at the University of Oxford. Previously, he was Professor of Archaeology in the University of Cape Town where he directed the Department of Archaeology’s Materials Laboratory.

Michael Bisson

Michael Bisson has been a Professor of Anthropology at McGill University, Montreal since 1974 and is currently on a post-retirement appointment there. His initial research (1971–1982) was on pre-colonial copper mining in Zambia. After that, his focus changed to the Middle and Upper Palaeolithic of western Eurasia. He has worked on projects in the United States, Canada, France, Italy, Spain, Portugal, Israel and Jordan. He is currently investigating the Early/Middle Stone Age transition in the upper Luangwa Valley of Zambia.

Maggie Katongo

Maggie Katongo was the curator of the archaeological collection at the Livingstone Museum, Zambia, until 2020 and is now a PhD student at Rice University, Houston, Texas. Her research studies human subsistence strategies and how animal agencies help shape human behaviour in the Iron Age period of southern Africa.

Fortune Munetsi

Fortune Munetsi is the assistant curator of archaeology at the Museum of Human Sciences in Harare, Zimbabwe. He is interested in landscape use and the cultural heritage management of rock art sites in southern Africa.