La fracturation osseuse : du fait technique à l’essai d’interprétation sociétale : l’exemple de l’antilope saïga du gisement magdalénien de Saint-Germain-la-Rivière (Gironde)

EnglishBones collected on Palaeolithic archaeological sites are rarely found whole. While a range of natural factors and mechanisms can be the cause of this bone fragmentation (e.g. carnivores, weathering, and sediment compaction), human activity is often a major agent, as bone fracturing takes place in many operational sequences involving the transformation and exploitation of animal resources, particularly in terms of the use of bone marrow and the bone itself as a raw material. The bone marrow contained in the medullary cavity of long bones is an important food resource for many human groups, particularly in periglacial areas, such as among the Nunamiut of Alaska or the Siberian Koriak. These groups each use different processes to remove the bone marrow. This variability is partly explained by the technical traditions and modes of consumption specific to each group, which often lead to a standardization of fracturing techniques within the group. Can recurring patterns of this kind be observed in the Palaeolithic context? And if so, is it possible to demonstrate the transmission of such processes in terms of the removal of the bone marrow? To help answer such questions, we present in this article a detailed study of the percussion marks observed on saiga antelope (Saiga tatarica) long bones from the upper complex at Saint-Germain-la-Riviere (Gironde), attributed to the Middle Magdalenian. This includes an inventory of the number of impact marks on each fragment, their nature, their arrangement in relation to each other, and their location on the anatomical element. The degree of percussion has been calculated for the different parts of the anatomical elements in order to establish whether there were any preferred impact zones. The patterns observed were then compared with those described in publications in order to establish their specific characteristics and to assess the parameters that may have affected such distributions of marks. Saint-Germain-la-Riviere has already been the subject of a detailed taphonomic study (Costamagno, 1999) demonstrating the significant role of Magdalenian hunter-gatherers in the accumulation and modification of bone remains and the limited impact of carnivores. This homogeneity in the constitution of the assemblage reduces the risk of confusion between human and natural agents in the attribution of the marks observed. The corpus studied was composed of 640 bone remains, all of which were fragments of the main long bones containing bone marrow (humeri, radioulnae, femurs, tibias, and metapodials). The faunal remains at Saint-Germain-la-Riviere were intensely fractured and present numerous human percussion marks that can be attributed to this activity of fracturing the bone. Almost 19% of the corpus presented such marks. No correlation was observed between the distribution of the percussion marks and the conservation/identification of the different skeletal parts. Recurrences in the location of the impact points were nonetheless identified. These recurrences varied in relation to the skeletal elements considered and differed in degree. In the case of the radii, for example, the vast majority of impact marks were found on the proximal parts, in contrast with the humeri and tibias for which the distribution of percussion marks, although more variable, appeared to indicate a selection predominantly in favour of the distal parts. The preferred percussion surface also varied according to the element, mainly the anterior surface in the case of the radii but the lateral or medial surfaces in the case of the humeri. The existence of such recurrences indicates that the arrangement of the impact points results from deliberate choice. This choice of location to perform the fracturing of the bone does not appear to be dictated solely by mechanical constraints (e.g. bone structure) or ergonomic constraints specific to each skeletal element. If that were the case, the patterns observed for a specific species would be relatively similar from one level to another and one site to another. However this is not the case, as at Saint-Germain-la-Riviere, for a single taxon, the saiga antelope, the pattern observed in the upper complex (Middle Magdalenian) differs from that observed in the lower complex (Lower Magdalenian). The most striking case is that of the radii, as between the two complexes the arrangement of the impact points is diametrically opposed. This variability is not specific to this species as at other sites attributed to different techno-complexes, differences in the choice of the location of the percussion marks have also been observed, particularly for reindeer and ibex. This is also the case for sites attributed to the same period. Thus, while we cannot completely exclude the possibility of a preferential choice in relation to the bone structure itself, the existence of such inter and intra-species variability suggests choices dictated in part by cultural factors. Furthermore, the analysis of percussion marks has allowed us to highlight in some cases the presence of several impact points on the same bone fragment. Thus, some of the bone fragments have multiple percussion marks (up to eight identified), sometimes located over a small area and in the form of chopmarks. This type of mark is generally attributed to the disarticulation stage of the limbs during the butchery process. Given their location on the bone element, this does not however appear to be the case here. Moreover, they do not appear to be of a technical nature and cannot be attributed to retouchers. One of the hypotheses that we can put forward here is that several attempts were made at fracturing the bone. This then raises the question of the tenacity and mastery of the technique and could imply that these bones were fractured by novices. francaisLa fracturation osseuse est une pratique couramment observee sur les gisements paleolithiques, celle-ci intervenant dans diverses chaines operatoires de transformation et d’utilisation des ressources animales, notamment alimentaires. La moelle osseuse, contenue dans la cavite medullaire des os longs, est une ressource alimentaire non negligeable pour de nombreux groupes humains, en particulier dans les zones periglaciaires, tels les Nunamiuts d’Alaska ou les Koriaks de Siberie. Differents procedes sont mis en œuvre pour sa recuperation ; leur variabilite s’explique en partie par l’existence de traditions techniques et de modes de consommation de la moelle, propres aux differents groupes. Ces traditions entrainent souvent une standardisation des procedes de fracturation a l’interieur de chaque groupe. De tels schemas recurrents sont-ils perceptibles dans le registre paleolithique? Si oui, est-il possible de mettre en evidence une transmission des gestes relatifs a la recuperation de la moelle? Afin d’apporter des elements de reponse a ces questions nous proposons dans le cadre de cet article, une etude detaillee des traces de percussion observees sur les os longs d’antilope saiga (Saiga tatarica), provenant de l’ensemble superieur Magdalenien moyen de Saint-Germain-la-Riviere (Gironde). Les schemas observes ont ensuite ete compares a ceux decrits dans la litterature afin d’apprecier leurs specificites et de discuter des parametres ayant pu influer sur cette repartition des traces. Les vestiges fauniques de Saint-Germain-la-Riviere sont intensement fractures et presentent de nombreuses traces de percussion d’origine anthropique attribuables a cette activite de fracturation de l’os. Des recurrences dans la localisation des traces de percussion ont pu etre mises en evidence. Celles-ci varient selon les elements squelettiques consideres et sont plus ou moins marquees. L’existence de telles recurrences tend a prouver que la disposition des points d’impact depend d’un choix delibere. Ces choix ne semblent pas etre dictes exclusivement par l’existence de contraintes mecaniques (e. g. la structure osseuse) ou ergonomiques specifiques aux elements squelettiques. Par ailleurs, l’existence d’une variabilite inter- et intra-specifique, observable d'apres les donnees de la litterature laisse a penser qu’il s’agit de choix dictes en partie par un facteur culturel. L’analyse des traces de percussion a egalement permis de mettre en evidence, dans certains cas, la presence de plusieurs points d’impact sur une surface reduite. L’une des hypotheses que l’on peut emettre ici serait qu’il y ait eu plusieurs tentatives pour fracturer l’os. Ces pieces posent alors la question de l’acharnement et de la maitrise du geste et pourraient evoquer des os fractures par des novices.