Archaeological and Archeometrical Approaches of the Chaîne Opératoire in Iron and Steelmaking: Methodology for a Regional Evolution Study

International audienceOver the last twenty years, archaeological and archaeometrical research implemented in Francehas made it possible to define the various stages of the chaîne opératoirein iron and steelmaking as wellas the indicators which are linked to them (archaeological structures, wastes). These studies revealthat the chaîne opératoiremay (or may not), split in space and time, but may also contain variousdegrees of intensity (mini-maxi production). This implies that the production sites can be of differ-ent natures : they may include partial or complete chaînes opératoires, and are part of a social context(e.g., rural, urban, specialized or domestic craft). The relationships within the chaîne opératoirecreatelinks between the sites and form a technological, economic and social network through trade in semi-finished and manufactured products. The evolution of these networks must be studied by taking intoaccount the cultural and political contexts of each period (e.g., hierarchical networks of sites andindividuals, consumption practices with respect to the metal) to draw up a coherent comprehensionof this organization. The determination of site activities (smelting, refining, elaboration, consump-tion, recycling), as well as intensity, enables realization of a dynamic cartography of these activities,both synchronic and diachronic. The physicochemical linkages between the ore, the smelting slag, thepost-smelting slag and the produced metal allow, eventually, comprehension of the connectionbetween sites which are part of the same exchange network. This, in turn, reflects the regional devel-opment of metallurgical organization and the trade in iron semi-products and manufactured goods.The typological attribution (morphology, impurities level, iron / carbon composition) of semi-products worked on the elaboration sites also permits refining the vision of what circulates and of whatthe sites acquire. Thus, an archaeological and historical study of these data can structure the relativeimage we have of these relations in the various epochs (Mangin et al.2000a).The synthetic flow chart presented in Fig. 1summarizes the various approaches. After presentingthe characteristic indicators of the stages of the chaîne opératoire, we shall set out the results obtainedby applying this methodology to iron and steelmaking activities in the North of the Paris Basin duringthe Iron Age II