NEW DATA ON THE LANDSCAPE OF MIDDLE OISE VALLEY DURING SUBBOREAL: STUDY OF THE ORGANIC SEQUENCE OF THOUROTTE (OISE, FRANCE)

The INRAP rescue excavation campaign at Thourotte "La Motte" (60), associated to the lansdcape development of the "SeineNord Europe" channel, revealed new archaeological and palaeoenvironmental information on the poorly-explored area of the Middle Oise valley, upstream of Compiegne. Geophysical and morpho-sedimentary survey of a palaeochannel that scraped a mound led to the implementation of a multidisciplinary approach (archaeology, sedimentology, pollen and wood analyses, dendrochronology, zooarchaeology, radiocarbon dating). While sediment analyses unveiled the evolution of the alluvial plain since the last glaciation, the other studies mainly dealt with the channel organic matter filling. This filling dates back to the Early Subboreal, between c. 3600 and 2700 cal BC. The local environment seems to be mainly composed of alder forest around which oaks tend to grow. Organic sedimentation starts during a period of forest surface recovery leading to a densification of tree cover. Around 3000 cal BC, the riverside vegetation is cleared and crops are cultivated. The presence of ruderal species indicates the practice of arable and pastoral farming. These agro-pastoral activities might originate from Late Neolithic populations, which left some scarce remains on the mound and in the channel.