On measuring the mean edge angle of lithic tools based on 3-D models – a case study from the southern Levantine Epipalaeolithic

The edge angle of lithic tools is an important source of information on the intended function and the manufacturing technology of these artifacts. Yet, previously proposed procedures, both traditional and computer-based, can be flawed by ambiguity in the artifact positioning and in the choice of the points or surfaces defining the angle. A novel method, based on digital 3-D models of the artifact, calculates the measure of the edge angle based on its complete shape, providing an accurate and repeatable measurement of this feature. The procedure includes the automatic, univocal determination of the area that best represents the angle between the two surfaces, further increasing the objectivity of the result. To test its power in providing novel archaeological insight, the method is tested on a series of assemblages of Epipalaeolithic microliths. The combination of the obtained quantitative data with the typology-based cultural attribution of the assemblages highlights possible connections between different areas in the Southern Levant.