Les pointes polies alpines des IVe et IIIe millénaires av. J.-C. : caractérisation expérimentale de la chaîne opératoire de fabrication

Abstract

Flat and piercing tips made of polished rock and bone are typical of the Late Neolithic in the Western Alps. Most of them, realised in tenaceous rocks (serpentinite and amphibolite), come from the internal valleys of the Alps in Switzerland (Valais), Italy (Val D’Aosta, Western Piedmont) and France (Savoy). Production sites have been identified at Bessans (Savoie) and Roreto (Piedmont), whereas unfinished tips are known on several sites of the Western Alps. Contextual examination allows it to be demonstrated that production occurred on the outcrops, or in their immediate neighbourhood. According to the archaeological facts, the operative process is simple: flat blanks (thin plates) were shaped out by retouching, then polished. The obtaining of the blanks and the manufacturing process are difficult to understand on the archaeological artefacts, so an experimental approach was necessary; this was done in 2003. The results allow us to argue that only one «chaîne opératoire» was used. In summary: the blanks are obtained from small massive blocks; these blocks offer a small but discernible schistosity; the use of heat is not required; obtaining blanks is the decisive step of the «chaîne opératoire»: their regular thinness conditions the regularity of the tip and the working time required for shaping; shaping is quite quick (half an hour to one hour), executed by retouching with a stone hammer, followed by more or less covering polishing. All the shapes and the dimensions known in archaeological contexts can be reproduced with no real variation in the difficulties. The levels of know-how appear in the symmetry of the tip and the straightness of the lateral edges. Manufacturing of the tips in polished rock does not require highly developed know-how for people who are familiar with working tenaceous rocks for axeheads. However, obtaining the best results calls obligatorily for the use of rocks from autochthonous or sub-autochthonous outcrops.