Revisiter le paradigme du « sol néolithique disparu » : géoarchéologie des modes d’occupation de la fin du Néolithique dans le sud-ouest du Bassin parisien. Le cas du site « les Grands Noyers » à Gas (Eure-et-Loir)

EnglishThe sedentary lifestyle of Neolithic societies places the settlement at the heart of archaeological issues. In northern France, research has mainly focused on sites with negative structures, whereas the frequent presence of clusters of artefacts was not considered as a potential element of the settlement structuration. However, the archaeological floor carrying essential data does approach this research question. Historically, at the beginning of the research on early Neolithic settlements in the Aisne Valley and throughout Eastern Europe, the soil, as an archaeological entity, was not identified. Also, it was considered, except for a few isolated cases, as not preserved. Since then, this observation has been challenged and the lack of detecting floors has limited our understanding of Neolithic settlements. The south-west of the Paris basin provides a relevant framework to investigate Neolithic soils and to question their absence. The end of the Neolithic in this region is still poorly culturally defined and building plans are largely unknown: buildings on posts of small modules and one monumental building. Nevertheless, numerous sites not stratified with artefact clusters (35 among the 79 sites identified) are discovered. In this context, where settlements are largely still poorly documented, it seems necessary to test if the cluster of artefacts constitutes a witness to the floor. We engaged an original geoarchaeological approach based on soil micromorphology to examine the sediment that contains these artefacts and thus characterise the formation processes of these archaeological layers. These elements then allow us to question ourselves on: -- the nature of the Neolithic floor and its variability to document the construction and functioning of inhabited spaces? -- the way in which they contribute to characterising the dynamics of occupation of sites at the end of the Neolithic period? To answer these questions, the study material comes from five sites located in the Beauce (Sours, Gas and Poupry) and Touraine (Pussigny and Maille) regions. The methodological approach is related to the geoarchaeology using soil micromorphology as a toolset. The strategy of sampling is twofold: stratigraphic sampling integrating all the thickness of the stratigraphy and the transition with the substrate and associated with a spatial sampling (37 sedimentary sequences). The study of thin sections allow to identify sedimentary organisations defined as "micro-ethnofacies". Resuming the patterns introduced since the 1990s and according to the constants observed, a first qualitative model of the Neolithic floor expressed by a classification of micro-ethnofacies is proposed according to layout and functioning. Then, the phasing of the set of micro-ethnofacies sequence from microstratigraphy analyses allows to restitute the partition of space according to the nature of the activities and trace its evolution depending on time. To illustrate the potential of the geaoarchaeological study, we rely on the example of the "les Grands Noyers"site at Gas with a thin stratigraphy which allows to propose a reconstitution of its functional history. The establishment of the settlement is characterised by extensive earthworks activities and levelling of the field beforehand to the construction of a building whose architectural foundations are in cob. The floors of the building are regularly spread screeds and recorded a high trampling. A courtyard floor develops on the outside above a slab of earth that creates a platform. Courtyard floors are sometimes maintained which underlines a rotation in the functioning of the activities that are dedicated to it. Once the space has been abandoned, the earthen architecture, subject to temperate climatic conditions, breaks up and ended up in its collapse. These original results confirm the preservation of human acts and practices in Neolithic floors. The identification of floors, constructed or not, and of their division in the space testifies, on the contrary, of the well conservation of the recorded information. According to the first observations, this is probably related in large part to the collapses of the cob construction or to rapid overlays such as colluvium. These results also contribute to highlight the informative potential of these thin stratified sites with clusters of artefacts which are a settlement with cob buildings and structured outdoor spaces of the courtyard type. Soil analysis demonstrates that Neolithic settlements had a though-out project involving earthworks and levelling activities. The floors are in most cases built according to several construction techniques. The relationship between the bases of the walls and the cluster of artefacts leads to the formation of wall effects (internal and external) and the walls can therefore be considered as structuring elements of occupying grounds. The sedimentary archives are true cultural documents and the results obtained bring new palethnographic data. They emphasise an important variability between the soils which belong to a partition of the space where the floor is characterised according to the nature, the time and the organisation of the activities. For the inner space, the typical floor is a very heavily used (intense trampling) constructed floor. However, the absence in most cases of microartefacts does not make it possible to specify the nature of the activities practised, perhaps because of conservation problems or waste management. These soils are distinguished by the maintenance they show as they are regularly maintained. The typical outer floors are courtyard floors where the cluster of artefacts reflects a space frequented and maintained at an irregular pace. Here again, the rarity of microartefacts tends to limit the identification of the activities practised. The paradigm of the 'disappeared Neolithic soil' is fading away, opening up rich palethnographic perspectives. francaisAu regard «de l'absence» des sols d'occupation neolithiques, les recherches sur l'habitat dans le Nord de la France sont basees sur des plans de bâtiment a partir de l'organisation des trous de poteau. Pourtant la presence dans le Sud-Ouest du Bassin parisien de sites peu stratifies a concentration de mobilier suggererait la preservation de sols d'occupation. En questionnant la relation entre le sediment et l'artefact, la demarche geoarcheologique, fondee sur la micromorphologie, vise a determiner les processus de formation de ces sites pour interroger la preservation des sols d'occupation ainsi que la nature des activites humaines qu'ils enregistrent. Cinq sites a concentrations de mobilier (Gas, Sours, Poupry, Pussigny et Maille) decouverts en Beauce et en Touraine ont ete etudies. La strategie d'echantillonnage etablie sur le terrain est double : stratigraphique, en integrant la transition avec le substrat, et spatiale entre coeur et peripherie des concentrations de mobilier. L'elaboration d'un modele qualitatif du sol neolithique, exprime par une classification de micro-ethnofacies d'amenagement et de fonctionnement a permis d'identifier sa nature. L'analyse microstragraphique contribue a restituer la partition de l'espace selon la nature des activites et de retracer son evolution dans le temps. Le site «les Grands Noyers» a Gas permet d'illustrer le potentiel de l'approche geoarcheologique engagee sur le sol neolithique et de proposer une reconstitution de l'histoire fonctionnelle de ce site : construction d'un bâtiment aux bases de mur en terre massive apres terrassement et nivellement du terrain, puis amenagement et fonctionnement des sols interieurs domestiques et exterieurs qualifies de cour. Les resultats acquis confirment la preservation, au sein des sols d'occupation neolithiques, des gestes et des pratiques humaines. Ainsi, le paradigme du « sol neolithique disparu » s'estompe ouvrant de riches perspectives d'ordre palethnographique pour l'habitat neolithique.