Backed point experiments for identifying mechanically-delivered armatures

The emergence of mechanically-delivered armatures was a crucial event in human evolution, indicating technological and cognitive advances. Morphometric analysis has been the most commonly employed method to explore this subject. While a morphometric analysis can demonstrate a potential capability as a projectile, it is inevitable that the analyzed sample includes artifacts that were not used as hunting weapons. Furthermore, proxies derived from ethnographic references might be dependent on spatio-temporal contexts. Thus, a reliable identification of spearthrower darts and arrowheads in archaeological assemblages requires new indicators. Here we present results of controlled experiments, using backed point replicas, designed to test a correlation between impact velocities and impact trace patterns. Macroscopic and microscopic analyses of experimental replicas indicated that complex fracture formation, including large numbers and dimensions of spin-offs as well as distinctive microscopic linear impact traces (MLITs), provide useful markers for determining mechanically-delivered backed points.