Retouched or not retouched: the impact of hammerstone morphology on the percussion marks to recover yellow marrow

International audienceIn many Paleolithic sites, the faunal remains are systematically broken by percussion, especially to recover the marrow. Indeed, the fact of yellow marrow was an important nutritional resource to many human groups, particularly during glacial and periglacial periods. Many studies highlighted the importance of percussion marks to identify and characterize anthropogenic occupations. Numerous studies based on experimental and ethnographical observations have focused on these percussion marks to recover the marrow of long bones both to understand the percussion techniques and to characterize their morphology. Currently, percussion marks are employed to approach the subsistence behavior of human groups during the Paleolithic. New methodologies are used for their analysis, for example, GIS or deep learning, which highlight the importance traces equally to the cutmarks. The lithic tools used for bone fracturing are subject to analysis. However, although this activity can be carried out with a simple raw pebble, choppers show traces of wear on their cutting edge, indicating their use for this activity. However, few experiments are interested in the link that may exist between the morphology of percussion marks and those of the hammerstone. We want to test the percussion mark variability depending on whether it is retouched or not and its raw material (basalt and quartzite). We performed an experiment focus on the long bone (bovids) breakage to extract marrow using the hammerstone on anvil technique to figure out this morphological relation. Four experimenters involved used the same tool each time to fracture 20 femurs, humerus, tibias and radio-ulnas (N=80 bones). This allowed comparison of both inter and intra element, and experimenter variations. Moreover, the use of an anvil and the systematization of the blow location made it possible to question both the formation and the morphology of the marks due to counterblow. Here we present the first results obtained concerning the suitability of raw or shaped edges for bone fracture. As well as the traces produced and their variability according to raw material. For the bone, our first results tend to show that there is a relationship between the morphology of the hammerstone and marks created during fracturing. The analysis of counterblow marks highlights the difficulty to characterize these marks. The results concerning bone fracturing are presented in more detail in an associated poster ("Justiniany et al." Poster title). This better characterization of percussion marks according to the type of tools used to provide a better understanding of the subsistence behaviors of Paleolithic populations. The future comparison with archaeological data will enhance