Experimental investigation of flake productions and the identification of problem avoidance strategies, applied to scraper reduction at Mount Carmel

Abstract

An investigation of problems which can occur during the process of detaching flakes from a parent piece of stone, and of the aspects of stone artefact morphology which increase or decrease the likelihood of problems occurring, is the focus of this thesis. Researchers with practical experience of knapping stone artefacts have cited various problems which can be experienced during the flake production process, but no program of experimentation has focused on evaluating the severity of different problems and the situations under which problems are likely to occur. This thesis explores problems which can occur during the unifacial reduction of flakes. A general discussion of the mechanics of the fracture processes which occur during flake production is undertaken. The outcome of this discussion is a comprehensive theoretical understanding of the flake production process, which incorporates previous work by archaeologists and materials scientists, and also generates new models of fracture processes which are relevant to the aim of understanding problems that can occur during artefact reduction. A program of controlled experimental flake production is carried out, to test hypotheses linking aspects of artefact morphology with problematic fracture outcomes. The program of controlled experiments "involves the striking of a total of 817 flakes from "blanks" whose morphologies are carefully controlled, to test the ways in which aspects of blank morphology increase or decrease the likelihood of problematic fracture outcomes. The experimental program reveals the extent to which different fracture outcomes create problems for continued reduction of an artefact. Further, it quantifies the way in which properties of artefact morphology affect the likelihood of problems occurring, and the difficulty involved for the knapper in overcoming problems as they occur. Variables of artefact morphology which increase or decrease an artefact's reductive difficulty are identified as a result of the controlled experimental research. The reductive difficulty of an artefact refers to the likelihood of problems occurring during reduction, and the severity of these problems. Archaeologically, having the ability to analyse the relative reductive difficulty of artefacts enables the identification of situations in which technological systems produce artefacts with low reductive difficulty. This could provide evidence of technological systems which are organised to produce artefacts with low reductive difficulty, to facilitate the reduction process. Such a system of technological organisation is conceptualised as an extension strategy. The methods of analysing the reductive difficulty of unifacially flaked artefacts is applied to artefact collections from two sites in the Levant, Tabun Cave and Mugharet el-Wad, excavated by Dorothy Garrod. Assemblages from the sites' excavation units are classified within the Middle and Upper Palaeolithic. Changes in artefact morphology are identified across the sites' assemblages, coinciding with the boundary between the Middle and Upper Palaeolithic, as well as within the Middle Palaeolithic. Change through time is cyclical, rather than uni-directional. Analysis of changes in the reductive difficulty of artefacts, in conjunction with an existing technique of measuring the extent of reduction carried out on artefacts, enables discussion of the emphasis which the knappers who created the assemblages placed on implementing extension strategies at different points within the archaeological sequence. The methods of analysing reductive difficulty developed by this thesis enhance our potential to generate explanations of stone artefact variability.