Le site moustérien d’Andance (Saint-Bauzile, Ardèche) : un habitat de hauteur en contexte basaltique dans la moyenne vallée du Rhône

The open-air site of Andance (Saint-Bauzile, Ardèche, France), located on the left bank of the Rhône river, is perched upon a basaltic dome (552 m) that has become isolated from the Coirons plateau by erosion. The site, jeopardised by the open-air mining of Miocene diatomite, was the object of a rescue excavation over some 3 500 m2 undertaken by Paléotime in 2008 and is comprised of a valley fill-sequence bearing a Middle Palaeolithic industry at its base, though in a secondary position among geliflucted megaforms with basalt blocks. Stratigraphic, use-wear and petro-archaeological approaches underline the considerable impact of postdepositional processes on the artefacts and highlight their significant redistribution. The technological study confirms the assemblage was reworked as well as sorted, but not contaminated by more recent industries. All the raw materials used at Andance were imported to the plateau as it is completely devoid of flint sources. These raw materials comprised quartz and quartzites collected from one or more drainage systems in proximity to the site, but mostly Barremo-Bedoulian flint selected from reworked formations associated with the Oligocene conglomerate which covers the limestone formations of the Barrès plateau, roughly 5 km from the site. They bear witness to regular access to a local mineral source. However, the local basalt was not exploited, which is in contrast to the documented behaviour of Neanderthals from the same period in the Massif Central. The main chaîne opératoire, represented from start to finish, focuses on the production of non-Levallois blanks, seldom retouched. The principal products obtained are éclats débordants (continually, partially, or cortically backed) as well as different flake forms normally associated with a discoid production method. One or several other chaînes opératoires are attested by the presence of Levallois products displaying diverse techno-morphological criteria and by a significant percentage of elongated products. Part of this production was carried out elsewhere and imported to the site. Tools (n = 62) compose 4.6 % of the total pieces with the Mousterian group being largely dominant with a scraper index of 94. Retouching, often located on the thickest edge of the piece, is generally scaled, short, or semiabrupt tending towards marginal and only slightly modifies the morphology of the blank. On the other hand, bifacial shaping and pebble tool reduction sequences are essentially carried out in quartzite ; these are probably incomplete and spatially fragmented. Quartz and quartzites, whose use is always limited on other sites of the region, play a distinct and determinant role : quartz represents a backup material whose exploitation is almost identical to that of flint, yet less diversified, probably due to its structural and textural properties. Quartzites are employed as part of a ‘ complementarity economy’ (Huet, 2006) where they occupy a particular function and may be used in specific activities. The combined importation of shaped pieces and pebbles reinforces the distinct economic and functional status of this material. The assemblage is assigned to a Mousterian techno-complex rare in bifaces and with a discoidal knapping method, which lies at the transition between early and late Middle Palaeolithic, probably earlier than OIS 5. The analysis of the pedosentimentary microfacies suggests that the basalt blocks and the industry were deposited before isotope stage 5. A thermoluminescence date obtained on a burnt flint has provided a terminus ante quem for the occupation of around 93 ka. This natural promontory offered numerous advantages and certainly played a decisive role in the choice of occupation for the Mousterians of Andance (i. e. protection and observation). We cannot precisely reconstruct the everyday landscape of the Neanderthals who camped here ; we may however presume the existence of a basaltic grit of blocks in the course of being exposed on the highest points and an occasionally humid small valley at the foot of the site. The geographic configuration was clearly paramount in the choice of location and it was around this base that seasonal activities were organized. The strategy of lithic provisioning adopted by the Mousterians of Andance seems to support this and corresponds to a ‘ provisioning of places’ as defined by Kuhn (1995). Rare exotic pieces such as silcretes demonstrate longer displacements outside of the normal economic territory. The different approaches and analyses developed for this site allow us to further our regional understanding of Neanderthal behaviour and shed new light on research perspectives for open-air sites. The geographic proximity and similar chronology to the site of Payre (dir. Moncel, 2008) offers potential for comparison, especially concerning questions of raw material economy and the spatial exploitation of a particular territory.
Le site moustérien de plein air d’Andance (Saint-Bauzile, Ardèche) est perché sur un dôme basaltique isolé du plateau des Coirons par l’érosion, en rive droite du Rhône. Le site actuel, menacé par une exploitation à ciel ouvert de diatomites miocènes, a fait l’objet d’une fouille préventive en 2008 par la SARL Paléotime. Il correspond à une séquence de comblement de vallon qui livre à sa base une industrie du Paléolithique moyen en position secondaire au sein de mégaformes gélifluées à blocs de basalte. Les approches stratigraphiques, tracéologiques et pétroarchéologiques soulignent l’importance de l’impact des processus postdépositionnels sur le mobilier, témoignant de sa forte redistribution. L’étude technologique confirme le caractère remanié et trié de la série, mais également l’absence de pollution par des industries plus récentes. Les matières premières employées à Andance sont toutes importées sur ce plateau qui est dépourvu de gîte siliceux. Celles-ci sont constituées de quartz et quartzites collectés dans un ou plusieurs réseaux hydrographiques à proximité du site, mais surtout de silex barrémo-bédouliens prélevés dans les formations remaniées associées au conglomérat oligocène qui recouvre les formations calcaires du plateau de Barrès, à environ 5 km du site ; elles témoignent ainsi de la fréquentation régulière d’un domaine minéral proche. La chaîne opératoire principale, entièrement réalisée in situ, est orientée vers une production de supports non-Levallois, rarement retouchés. Les chaînes opératoires de façonnage de pièces bifaciales et de galets aménagés se manifestent essentiellement sur quartzite et sont probablement incomplètes et fragmentées dans l’espace. La série est rapportée à un technocomplexe moustérien à rares bifaces et à débitage Discoïde situé à la charnière entre Paléolithique moyen ancien et récent, probablement antérieur au stade isotopique 5. Ce promontoire naturel offrant de multiples avantages a sans doute joué un rôle déterminant dans le choix des installations moustériennes. Les différentes approches et analyses développées sur ce site permettent d’enrichir nos connaissances régionales sur les comportements néandertaliens et procurent une vision nouvelle sur les perspectives de recherche en contexte de plein air.
Bernard-Guelle Sébastien, Rué Mathieu, Fernandes Paul, Courty Marie-Agnès, Piboule Michel, Coudenneau Aude, Argant J., Picavet Régis, Dawson Marie-Claire. Le site moustérien d’Andance (Saint-Bauzile, Ardèche) : un habitat de hauteur en contexte basaltique dans la moyenne vallée du Rhône. In: Bulletin de la Société préhistorique française, tome 108, n°4, 2011. pp. 671-695.