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Generally speaking, charcoal analysis is based on identifying and counting charcoal fragments in order to calculate the relative variations in taxa frequency. All post-depositional processes are likely to induce fragmentation of the anthracological material, raising the question of the representativeness of taxa. Based on an innovative experimental approach combining both charcoal analysis and biomechanics, this paper explores how the mechanical properties of charcoal can influence the fragmentation and the quantification of species in anthracological assemblages. We carried out standardized laboratory compression tests on 302 samples issued from 10 taxa, charred at three different temperatures, in order to characterize the mechanical properties of common species in temperate and Mediterranean Europe. Our results highlight the differential responses of the tested species in terms of resistance to compression and fragmentation, two processes which do not appear to be correlated. Charcoal is very resistant to pressure (up to 22.5 MPa). Our results show that significant fragmentation differences exist between taxa. The total number of fragments after compression is largely dependent on the species, regardless of the charring temperature. However, this interspecific variability is more significant for small fragments [1e2 mm], than for larger fragments [2e4 mm] and >4 mm, with the exception of Quercus, which displays differential reactions to compression. Finally, a multifactorial analysis brings to light the impact of the physical and anatomical characteristics of the different species on charcoal fragmentation.

Birch bark tar, the oldest adhesive known in Europe, was widely used during Prehistory. This material, produced by the dry distillation of birch bark, has been identified in various spheres of activities and provides valuable information on the know-how and technical and territorial systems of past societies. This biomaterial can also provide evidence on socio-economic networks and mobility. However, very little is known about the production systems of birch bark tar during Prehistory, including the Neolithic period. The lack of findings in the archaeological record necessitates the development of an approach that combines experimental archaeology and biomolecular chemistry. We present here (1) the results of experiments in which different birch bark tar production systems were tested and (2) the molecular signatures of the birch bark tars produced according to different processes based on the use of ceramic vessels. The key role of bark quality is highlighted for the first time. This study also details direct archaeological inference of the experimental results obtained: a total of 23 samples from the site of Nice-Giribaldi (France, second part of the fifth century BCE) was investigated. Different categories of birch bark tars were identified during Neolithic in the south of France, providing evidence for the existence of complex manufacturing systems and procurement networks.

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a b s t r a c tWe present here a new approach combining the microscopic characterization of fungal decay features and the fragmentation degree of the charcoal remains from Middle Palaeolithic combustion structures: features H4 and H11 from Abric del Pastor, unit IV (>75 ka BP) and features H50 and H57 from El Salt, unit Xb (ca. 52 ka BP), Eastern Iberia. The observation of wood degradation patterns that occurred prior to charring followed by their quantitative analysis according to previous experimental studies revealed differences between the alteration degrees of the firewood used in the hearths, highlighting the existence of firewood acquisition criteria based on dead wood gathering and also suggesting smoke-related functions. Coupled with fragmentation analyses, this method highlighted possible post-depositional processes affecting the higher degraded charcoals. These results lead us to propose a quantitative analysis of the fungal decay patterns on Middle Palaeolithic charcoal reinforcing the previous hypotheses about dead wood gathering among Neanderthal groups as an accessible and available resource in the surroundings. These data have significant implications for the interpretation of firewood use and management by Palaeolithic hunter-gatherers which was traditionally defined as an opportunistic activity according to the absence of selection criteria based on specific taxa.

Economie des combustibles (bois et lignite) dans l'abri moustérien des canalettes De l 'expérimentation à la simulation des besoins énergétiques