Mechanical characterization of raw material quality and its implication for Early Upper Palaeolithic Moravia

Raw material mechanical tests were conducted to answer the question whether differences in raw material procurement among Early Upper Palaeolithic populations in Moravia (Czech Republic) may have been driven by different mechanical properties of those materials. Characterization of mechanical properties of erratic flints and Krumlovský les I type chert show that the relatively finer-grained erratic flints, preferred by local Aurignacian populations, are more easily and probably also predictably knapped at higher speeds, such as reached with soft (antler, wood) percussors, whereas cherts of Krumlovský les I type, exploited by both Szeletian and Aurignacian populations, are more resistant to fracture propagation. This implies the suitability of the former material for fine blade and bladelet production, and of the latter to projectile (e.g. Szeletian leaf points) manufacture, and possibly explains the export of leaf points from Szeletian areas (the Krumlov Forest) to Bohunician and Aurignacian sites within Moravia. Exploitation of erratic flints was easier as regards Aurignacian, and probably entire Upper Palaeolithic knapping technology. Certain tasks, however, were better met with other raw materials, thus reflecting the relativity of chipped stone raw material quality perception in the Palaeolithic.