Change and continuity in metal technology: iron production in the first and second millennium CE in Mbinga, southwestern Tanzania

Abstract

Mbinga is one of many areas in Tanzania with deep-rooted evidence of archaeology. Archaeometallurgically, the area has remained terra incognita. This paper focuses on Mbinga’s technological change and continuity of iron production techniques in the first and second millennium AD. To achieve this, archaeological data were collected through ethno-history, archaeological survey, excavation, and physical attribute methods, while archaeometric data were generated through optical microscopy, electron microscopy, and metallographic techniques. The results indicate that over the last 1500 years, there has been technological change in iron smelting techniques in terms of furnace charging platform, slag-pit provision, slag tapping, use of multiple tuyeres per tuyere port, reduction efficiency, utilized iron ore, and final smelting product. While change took place, there has been technological continuity in the furnace construction materials, forced air supply, and spatial organization of iron smelting activities. The change and continuity in the technology of iron production in Mbinga were probably driven by demand for iron tools for socio-economic purposes, environment, technological efficiency, and the demand for production of carbon-rich steel tools.