Production and provenance of gold and tin in the protohistoric and antique Occident – MINEMET

Abstract ANR 2011 - MINEMET

The acquisition and the exchange of metals constitute one of the economic poles structuring ancient societies since the beginning of the Protohistory. To find and to document the centres of production of metals it is necessary to have technical, chronological and constrained data on the different workshops, which constitute the mines.
In this project, we suggest characterizing by the chronology, the dynamics of working, the physics and the chemistry of materials, new mining territories exploited from Protohistory up to Antiquity. The project is going to be developed on three mining regions having been exploited for their precious alluvial deposits by different Celtics tribes i.e. gold in the Lemovices (Limousin, France) and the Petrocores (Périgord / Limousin, France) and to Cerretanes (Cerdagne, France), finally for the tin in the Eduens (Morvan, France).
The mining archaeology is a recent discipline, which is practised in connection with the earth sciences and the physico-chemistry. By the elemental and isotopic chemical characterization of ores, metallurgical wastes and metal pieces it is possible to propose geographical location of mining production. This systematic approach aims to follow the metal throughout the Chaîne Opératoire (mining districts to ingots/objects). But this approach is relevant if the selected samples result from coherent and well-informed archaeological contexts and it is rarely the case, specifically for the ores. The study is going to concern mines, opened in alluvial deposits. Although still visible on the field, these ancient works, vestiges of intense mining through hydraulic power of alluvial gold or tin (cassiterite), were mostly interpreted as evidences of natural erosion. These alluvial deposits are rare in Gaul, still little studied and they had only recently discovered. Their study is a tremendous challenge, because they brutally burst into historic contexts where the mining and the contribution of rare metals were totally ignored data, especially for the Protohistory.
A characterization of the mining districts and the associated metallurgical residues will be made using geochemical, elementary analyses and multi - isotopic on the alluvial gold and tin. We wish to evolve towards a finer characterization of the ancient mines in passing to the multi - isotopic approach (Pb, Ag, Fe, Cu) on the territory of the Gaul between the Iron Age and the Roman time when no research exist for the moment.
Furthermore, this project could allow to use LIDAR technique to map them and the still experimental one of Indoor/GPS to mapped them rapidly and in details. Finally, alluvial mines have very rarely been the object of excavations and have been generally dated in an excessive and uncontrolled way only by spatial association with classic archaeological sites located in their vicinity. A detailed knowledge of the relative chronology of the mining works will allow us to locate the best areas for archaeological surveys aiming to date and to document by a relevant approach the different phases of the mining activity on these sites.
Three CNRS laboratories (NATIONAL CENTER FOR SCIENTIFIC RESEARCH, France) are included in this project. They have the experiences to drive the studies regarding mining archaeology (TRACES), geology - geomorphology (GET) and geochemistry (LGL, ENS-Lyon). Furthermore, we are strongly supported by the European Archaeologic Centre of Bibracte. Thus, this ANR combines all the necessary conditions to resolve our study.