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Early Use of Pressure Flaking on Lithic Artifacts at Blombos Cave, South Africa

Ancient Innovations Pressure flaking is a method of forming points, grooves, and notches on stone tools in which a tool is pressed up against another stone, instead of striking it. It has been thought to be a fairly recent innovation, arising in the Upper Paleolithic 20,000 or so years ago. Mourre et al. (p. 659), show that tools from Blombos Cave, dating to about 75,000 years ago, have grooves and patterns resembling production by heat treatment followed by pressure flaking. Replication experiments were performed using similar source material followed by microscopic study of the tools. Despite the evidence for an early innovation, it seems that pressure flaking was not used widely elsewhere until much later; thus, such early innovations may have been sporadic ephemeral. Tools dating to ~75,000 years ago show evidence of pressure flaking, long before the technique became widespread. Pressure flaking has been considered to be an Upper Paleolithic innovation dating to ~20,000 years ago (20 ka). Replication experiments show that pressure flaking best explains the morphology of lithic artifacts recovered from the ~75-ka Middle Stone Age levels at Blombos Cave, South Africa. The technique was used during the final shaping of Still Bay bifacial points made on heat‐treated silcrete. Application of this innovative technique allowed for a high degree of control during the detachment of individual flakes, resulting in thinner, narrower, and sharper tips on bifacial points. This technology may have been first invented and used sporadically in Africa before its later widespread adoption.