Le Gravettien du Fourneau du Diable (Bourdeilles, Dordogne) : révision chronoculturelle des ensembles lithiques de la «Terrasse inférieure »

EnglishIn France, the Middle Gravettian (ca. 32-29 ka cal. BP) is characterized by two " facies " principally defined on the basis of their lithic industries: the Noaillian is recognized by the presence of Noailles burins and the Rayssian, which has become better recognized since the 2000s, is characterized by a particular method of reducing Raysse nuclei (formerly burins) to produce a type of armature termed the " la Picardie " bladelet. The Noaillian stratigraphically precedes the Rayssian in Northern Aquitaine archaeological sequences, and these two typo-technical traditions occupy partially overlapping territories. Whereas the Noaillian is observed primarily in southwestern France (from the Pyrenees to the southern Loire river), with extensions into Cantabrian Spain, southeastern France and Western Italy, the geographical distribution of the Rayssian extends into more northerly regions (northern Aquitaine Basin, the Centre region, Burgundy and Brittany). This has led many researchers to postulate that the Rayssian may be an adaptation to different environments than those exploited by the Noaillian. However, this view is potentially biased since a review of the published literature reveals a wide disparity in the types and quality of information available for individual archaeological sites. At Le Fourneau du Diable (Bourdeilles, Dordogne), for example, the existence of several Gravettian phases (initially " Perigordian ") has been proposed by different authors. Excavated between the 1910s-1930s by D. Peyrony, this site was successively attributed to the " Perigordian IV " (Lower Gravettian), the Lower Noaillian (Noaillian stricto sensu) and the " Recent Noaillian " (Rayssian). Recent excavations directed by M. Baumann make it possible to better evaluate these chronocultural attributions and to specify biases introduced by the excavation methods employed during the previous century. Our study consists of a typo-technical examination of the lithic industry recovered from a test unit (1 m.) excavated during 2015 on the site's lower terrace into the back dirt from previous excavations. A review of the Peyrony collection was also carried out in order to supplement and confirm previous studies' observations. The aim here is to identify the different chronocultural episodes present in the lower terrace's deposits, as well as to compare our chronocultural attributions to those proposed previously. The Solutrean is represented by various retouched artefacts attributable to the Upper or Final Solutrean (Laurel-leaves and shouldered points) and by debitage diagnostic of bifacial reduction (bifacial thinning flakes). The Gravettian can be divided into three groups: 1) an " unspecified " Gravettian component, represented by ubiquitous retouched elements common to most of its sub-phases (e.g., microgravettes, backed and truncated bladelets); 2) a Noaillian assemblage made up exclusively of Noailles burins and their diagnostic microlithic spalls; and 3) a discreet Rayssian assemblage, represented by a set of technical waste related to the " Raysse method " (Raysse spalls and bladelets, Raysse burin-cores, blades with " oblique lateral faceting " on the platform) and some fragments of retouched bladelets compatible with the " la Picardie " bladelet type Comparisons of the test unit assemblage to material present in the Peyrony collection show that, in the latter, the Noaillian and the Rayssian are significantly under-represented. It is likely the result of multiple factors, such as the low archaeo-stratigraphic resolution of the Peyrony excavations, or their selection of complete, well-made and easily recognizable retouched tools at the expense of smaller tools (e.g., bladelet armatures, Noailles burins) and unretouched artifacts. The fact that the Rayssian technical system was only formally recognized years later could also have played a role in its diagnostics being overlooked by Peyrony. Unfortunately, the effects of these potential biases on assemblage composition, along with the mixing of excavated materials do not allow one to reliably discriminate most artifacts by cultural phase, nor to characterize in detail the nature of the Fourneau du Diable's Gravettian occupations. Moreover, detailed interpretations are hindered by the fact that comparisons between the Noaillian and the Rayssian are difficult since the two sub-phases are not defined on the same typo-technical basis. The recognition of the Noaillian and the Rayssian in the Fourneau du Diable's lower terrace deposits demonstrates that attributing cultural designations to archaeological sites on the basis of tool type counts from old excavations can be affected by biases thus leading to inaccurate estimations of an archaeological phase's geographic distribution. In fact, many diagnostic artifact types have discreet characteristics that are sometimes difficult to recognize, and as a result their presence may go unrecognized in Gravettian levels at sites that were excavated with non-modern methods. Moreover, since little is known about the " Noaillian " technical system in regions outside of the Landes and the Pyrenees, it is possible that this archaeologically defined entity in fact groups together a number of discrete technical traditions that share the same form of burin (i.e., the Noailles burin). It is therefore important that future work include systematic and critical examinations of old collections, as well as new excavations at key sites. With such work, cultural attributions of site levels will be more accurate, the geographic distributions of the Noaillian and the Rayssian will be more accurately estimated, and such data will benefit the application of certain approaches, such as ecological niche modeling. francaisEn France, le Gravettien moyen est caracterise par deux facies lithiques : le Noaillien, marque par la presence de burins de Noailles, et le Rayssien, identifie par la reconnaissance de la « methode du Raysse ». Malgre un important recouvrement geographique, le territoire d'expression du Rayssien semble plus septentrional que le Noaillien, ce qui a ete a l'origine de nombreuses hypotheses. Cependant, il se peut que l'estimation de leurs aires de repartition geographique soit biaisee, puisqu'un examen de la litterature revele une forte disparite dans le degre d'informations disponibles pour chaque site. Le site du Fourneau du Diable (Bourdeilles, Dordogne) illustre ce biais. Fouille dans les annees 1910-1930 par D. Peyrony, ce site a ete successivement attribue au Gravettien ancien, au Noaillien stricto sensu et au Rayssien. La reprise recente des fouilles (dir. M. Baumann), permet de reconsiderer ces attributions et de preciser les biais induits par les methodes de fouilles anciennes. Notre etude consiste en un examen typo-technique de l'industrie lithique issue du sondage realise en 2015 sur la « Terrasse inferieure », et vise a reconnaitre les differents episodes chronoculturels identifiables dans la serie. Sans surprise, Solutreen et Gravettien y sont representes. Les pieces rapportees a ce dernier techno-complexe peuvent etre attribuees a une phase indeterminee du Gravettien, au Noaillien ou bien au Rayssien. Ces deux derniers ensembles sont largement sous-representes dans la collection Peyrony. Cet exemple invite a considerer les donnees issues de fouilles anciennes avec prudence. De par la discretion de leurs marqueurs, leur reconnaissance recente (pour le Rayssien) ou leur caracterisation insuffisante dans la region (systeme technique « noaillien » dans le Nord de l'Aquitaine), il apparait important de reevaluer des collections anciennes ainsi que de reprendre des fouilles sur certains gisements-cles afin de mieux apprehender les problematiques de cette periode.