Development of Metallurgy in Eurasia
Roberts, Benjamin W., Thornton, Christopher P., Pigott, Vincent C., Antiquity
Modern debates regarding the spread of metal use in Eurasia can be traced to the work of Theodore Wertime (1964, 1973), who argued that the expertise required to smelt metal was such that it could only have been discovered once, and to Colin Renfrew (1969), who proposed multiple independent centres of metallurgical invention. Whilst subsequent surveys highlighted the potentially deterministic role of regional geologies (Charles 1980), and the increased quantity of new data (Muhly 1988), they did not resolve the issue. In the 20 years since, there has been a flood of new data from fieldwork and laboratory projects, as well as far greater access to regions throughout Eurasia. These have been accompanied by new theoretical paradigms in archaeology that have challenged the purely technological perspectives of the debate and demonstrated how early metallurgy was shaped instead by cultural forces of the societies involved. The foundations of this new approach can be traced to the eminent materials scientist Cyril Stanley Smith (1981) who argued that the adoption of metallurgy derived not from some technical or economic necessity, but from aesthetics and specific socio-cultural desires. People did not need copper tools; they wanted copper tools. After all, the earliest metal objects were not necessarily superior to wood, bone, flint, obsidian or ceramics for performing everyday tasks, and these other materials continued to be used for thousands of years alongside metal tools.
Our aim is therefore not only to re-evaluate where and how early metallurgy occurred, but also to understand the broader processes underlying its transmission and earliest development. Within this there are several fundamental questions that we seek to address. Was metallurgy invented at a single place or invented independently in multiple locations throughout Eurasia? Is there significant variation when different metals are investigated and compared? What were the motivations for the invention and innovation of metallurgy and how did these occur throughout Eurasia?
We will show that metallurgy derived from the desire by the early agricultural and agro-pastoral communities in Southwest Asia (c. eleventh-ninth millennium BC) to adorn the human body in life and death using colourful ores and naturally-occurring metals. It is only in the subsequent millennia that the application of heat in a controlled reducing atmosphere led to the smelting of metallic ores to produce lead, copper, copper alloys, and eventually silver. The use of metals spread throughout Eurasia usually by the acquisition of metal objects as 'exotica' and often then by the movement of people possessing metallurgical expertise. However, the metals, production techniques and object forms used in each early region reflect local standards, implying a process of incorporation and innovation by the communities involved rather than a straightforward or inevitable adoption.
Metals, origins and chronologies
The development of metallurgy in Southwest Asia began long before the application of fire to naturally occurring metals. Indeed, the use of blue and green copper ores for beads, pendants and pigments was a critical step in the Neolithic, occurring at early agricultural and agro-pastoralist sites dating to the eleventh-ninth millennium BC (Figure 1a) at sites such as Shanidar Cave and Zawi Chemi in north-eastern Iraq, Hallan Cemi in eastern Turkey and Rosh Horesha in Israel (Yener 2000; Bar-Yosef Mayer & Porat 2008). The increased working of naturally-occurring or 'native' copper as well as copper and lead ores is demonstrated at sites such as Cayonu Tepesi in eastern Turkey, where metallographic analyses have shown evidence of annealing c. 8000 BC, indicating the early application of heat to the production process (Maddin et al. 1999). Native copper exploitation flourished in this core area through the seventh millennium BC while other metals, notably lead and (in the early sixth millennium BC) meteoritic iron, appear for the first time (Schoop 1999). …