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Quantifying Edge Sharpness on Stone Flakes: Comparing Mechanical and Micro-Geometric Definitions Across Multiple Raw Materials from Olduvai Gorge (Tanzania)

Published version
Peer-reviewed

Type

Article

Change log

Authors

Bartkowiak, T 
Macdonald, DA 
Mietlinski, P 
Gapinski, B 

Abstract

jats:titleAbstract </jats:title>jats:pIn line with engineering research focusing on metal tools, techniques to record the attribute of ‘edge sharpness’ on stone tools can include both mechanical and micro-geometric approaches. Mechanically-defined sharpness techniques used in lithic studies are now well established and align with engineering research. The single micro-geometrically-defined technique—tip curvature—is novel relative to approaches used elsewhere, and has not explicitly been tested for its ability to describe the attribute of sharpness. Here, using experimental flakes produced on basalt, chert, and quartzite sourced at Olduvai Gorge (Tanzania), we investigate the relationship between tip curvature and the force and work required to initiate a cut. We do this using controlled cutting tests and analysis of high-resolution microCT scans. Results indicate cutting force and work to display significant dependent relationships with tip curvature, suggesting the latter to be an appropriate metric to record the sharpness of lithic tools. Differences in relationship strength were observed dependent on the measurement scales and edge distances used. Tip curvature is also demonstrated to distinguish between the sharpness of different raw materials. Our data also indicate the predictive relationship between tip curvature and cutting force/work to be one of the strongest yet identified between a stone tool morphological attribute and its cutting performance. Together, this study demonstrates tip curvature to be an appropriate attribute for describing the sharpness of a stone tool’s working edge in diverse raw material scenarios, and that it can be highly predictive of a stone tool’s functional performance.</jats:p>

Description

Keywords

Edge Geometry, Cutting Performance, Focus Variation Microscopy, Edge Profile Curvature Analysis, MicroCT, Basalt, Chert, Quartzite

Journal Title

Journal of Archaeological Method and Theory

Conference Name

Journal ISSN

1072-5369
1573-7764

Volume Title

Publisher

Springer Science and Business Media LLC
Sponsorship
Royal Society (RGS\R1\211318)
Royal Society (RGS\R1\211318)