A Mechanical Framework of Conchoidal Flaking and Its Place in Lithic Systematics

The identification of morphological design in lithic products and of their chaînes opératoires is usually based on implicit assumptions about technical choices on the part of the prehistoric agent. Rarely if ever, the latter follow from an understanding of the physico-mechanical processes engaged in the execution of sequences of percussive reduction and, therefore, the precise role of alleged technical decisions in morphological pre-configuration. This paper concentrates on conchoidal flaking. Its aim is to map discrete mechanical variation, following upon a heuristic exploration of the relationships between energetic, morphological, and percussive parameters under control of a flint knapper. Using an experimental set of glass flakes mechanically produced under controlled laboratory conditions, the analysis of variation in conchoidal flaking culminates in the distinction of four flake types. Using these type thresholds as a reference framework, an analysis of procedural variation in lithic production can be conducted. By way of example, the Levallois flake production system is assessed relative to this referential. Distinct deviations are found and a few propositions as to the mechanical and technical essence of Levallois are formulated. The paper concludes that operational theories of this kind may form a powerful grammar for structuring the archeological record. Uniformitarian in nature, it can be safely assumed that they were incorporated in the operational knowledge of prehistoric agents. Depending on the mechanical windows occupied by the morphological outcomes they targeted, corresponding technical decisions were made.