Pratiques alimentaires au Néolithique moyen : nouvelles données sur le site de Pontcharaud 2 (Puy-de-Dôme, Auvergne, France)
Authors: André Guy , Cabut Sandrine , Loison Gilles , Herrscher Estelle , Schmitt Aurore , Goude Gwenaëlle 
Published: February 2017

This paper presents new stable isotope data (δ13C and δ15N) on the Middle Neolithic human group from Pontcharaud (Puy-de-Dôme, Auvergne, France), in order to determine a dietary pattern for both individuals and the entire group. The region considered is particularly interesting for its environmental diversity and for the possibility of exploiting various food resources. The acquisition of new Neolithic palaeodietary data in a geographic area not studied until now, and different from previous research, allows the development of a comparative approach to understanding foodstuff choices including social and environmental aspects. Indeed, data are analyzed within the environmental and social context, which helps to establish a regional comparison with other contemporary populations in the south of France, characterized by various subsistence economies. This comparison aims at understanding possible dietary differences between southern human groups and populations from central France during the second half of the 5th millennium BC, and checking if diet could be linked to a specific environment and/ or to cultural choices. The site of Pontcharaud 2 is located in Clermont Ferrand in Central France (Auvergne). It is composed of a large funerary complex from which radiocarbon dates from bones indicate a chronological range between 4460 and 4030 BC cal. (LY7916 : 5640 ± 70 BP ; LY7918 : 5330 ± 55 BP ; LY 7917 : 5430 ± 50). In our study, two other radiocarbon dates were performed on human bones from the multiple deposit. The results (5350 ± 40 BP Poz-41914 : 4324-4051 BC cal. ; 5380 ± 40 BP Poz-41915 : 4335-4059 BC cal.) also indicate that this specific group belongs to the same period as the rest of the necropolis. The number of burials and the preservation of human remains allowed much information to be obtained regarding bioarchaeological aspects as well as funerary practices. Indeed, osteological work was carried out prior to the isotopic analysis. According to the growth stage, different methods were used to estimate individuals’ age at death. Immature subjects were divided into three subgroups in order to apply statistical processing : [ 0-4], [ 5-14] and [ 15-19] years old. These subgroups were defined according to biological criteria. Sex assessment was performed on adult remains thanks to the ’ DSP’ method (probabilistic sex diagnosis) established on the basis of metric data. Archaeological criteria considered for this study are, on the one hand, the presence or absence of perennial funerary architecture, and, on the other, the distinction between individual or multiple burials. δ13C and δ15N were analyzed on bone collagen from humans and animals in order to obtain individual dietary data, more particularly on the environments exploited (e. g. marine vs. terrestrial), and on the position of the individual within the trophic system (e. g. herbivore vs. carnivore). Adult (n = 37) and immature (n = 21) bones were selected with associated faunal material such as sheep/ goat, cattle and pig (n = 7), and the collagen extracted was measured by EA-IRMS. Results are consistent with the consumption of terrestrial animal protein for most of the individuals. The major part of the group seems to have consumed a significant quantity of herbivore meat coming from local resources. However, the wide nitrogen isotope range indicates different access to animal protein according to individuals. Thus, we suspect several subjects consumed 15N enriched resources. Among 15N enriched resources, and considering the local environment (semi-mountainous with an accessible fluvial network), freshwater fish and/ or young animals could be good candidates. Isotopic variations seem not to be linked to sex or age, but could reflect social variations in relationship with burial practice specificities (individual burial vs. multiple burial or deposit). Indeed, statistical tests applied to compare individuals buried in single or double graves and individuals from the multiple deposit highlight a significant isotopic difference for both carbon and nitrogen. The seven subjects from this specific deposit seem to have had less animal protein intake than the other members of this community, and/ or they had consumed food resources from a distinct isotopic environment. Seven individuals were excavated from this deposit : five adult men and two children. The status of these subjects comparatively to the rest of the group was widely debated and still commented. Our results underline the particularity of these people and suggest a link between their diet and their social status and/ or their exogenous geographic origin. A comparison with other Middle Neolithic sites from the southern region highlights various dietary patterns according to the region and the environment. The human group from Pontcharaud 2 shows the highest δ15N values compared to groups located inland (Garonne), and those located close to the Mediterranean coast (Languedoc). To explain these differences, we propose the hypothesis of more animal protein intake and/ or more 15N enriched protein intake (freshwater fish, young animals such as calf) for the Pontcharaud human group. This dietary pattern could be linked to local particularities such as climate and the semi-mountainous landscapes. Unfortunately no zooarchaeological study which could support our results is available for the moment. However, based on stable isotope analysis we can suggest regional trends in subsistence economy patterns : on the one hand, human groups living inland, in a hilly/ semi-mountainous landscape, more mobile and consuming more wild resources (aquatic/ terrestrial), considered as herders, and, on the other hand, a population located more on the plain, more sedentary, consuming no/ few wild resources, considered as farmers.