Archaeological Heritage of Salt: From a French archaeological site (Les Fontaines Salées, Yonne) to a European overview for the Prehistoric times

International audienceThe question is often asked about the origin of salt exploitation on ancient production sites. On historical or archaeological heritage sites, the answers often given are hypothetical or banal, such as « Since Prehistoric times » or « Since the Celt ». However, material evidence for such assertions is generally rare and, when it does exist, it is given very little emphasis. To approach the history of the archaeological heritage of prehistoric salt exploitation, we have chosen a symbolic site: the Fontaines Salées in Burgundy (Saint-Père-sous-Vézelay, France). After nearly a century of discoveries around these salt springs, we study how the archaeological heritage has been reshaped: from traditional Roman thermal baths to the unexpected discovery of Neolithic wooden wells (23rd century BC) still in place and visible. Discovered by chance under the Roman walls of a thermal bath (Fig. 1), genuine water collection wells were constructed between 2309/2299 and 2223 BC (dates are in close accord with the 14C AMS dates). The dendrochronological dates as well as the typological study of the 16 oak trees hollowed out and set over the spring-head to capture the brine, give additional and totally original information for the period in question. Certain oaks were collectively chopped down using copper or bronze axes, and different segments of a single trunk were used by at least two different groups, identified by means of dissimilar technical work-habits. The selection of these large and rare oak specimens probably implies that they were held in reserve over several generations. Given the total absence of charcoal sediments around and in these Neolithic wells, it is improbable that the brine was used to produce salt by evaporation or salt laden ash. During the Early Bronze Age, the site of Fontaines Salées was abandoned and the wells were rapidly filled by the riverine deposits of the Cure River. At the end of the Late Bronze Age IIa, some of the wooden well lining trunks were reused, probably to supply the farm animals with drinking water. The production of salt by evaporation can in fact only been demonstrated as from the early Iron Age. The function of these well lining logs over a feeble concentration of brine now needs to be interpreted using different hypotheses than the production of a "salt" which must have contained as much potash from the wood fire as genuine sodium chloride.This example illustrate how the Prehistory of salt is integrated into the cultural heritage as a result of chance discoveries at historical sites, destructions or reorganisations of space. But generally, far from the archaeological realities and their diversity (Fig. 2), in the absence of recent archaeological field studies, the hypothetical ancient data of the origins of salt exploitation is integrated into current discourses and used to justify decisions involving tourism, ecology or health (spas)