The mechanics and kinematics of freehand and anvil-supported flake retouching: Unpacking the technology of stone tula adzes from the Scarsdale 1 cache, Queensland, Australia

The tula adze is one of the best-described artefact types of the Australian archaeological record. Historical records describe the production of these retouched flakes and their function as hafted woodworking tools. A thick, short flake with a prominent bulb of percussion was retouched into shape across the distal end using either a hard hammerstone or a wooden indentor, with further retouch occurring during the life of the tool as it was used and resharpened. Flake retouching in Australia was historically depicted to have been done freehand, by holding the flake in one hand and the indentor in the other. Using data from the Scarsdale 1 cache from Pitta Pitta Country, western Queensland—a group of 60 tulas buried together in the context of an extensive exchange system operating through this region—this paper presents archaeological evidence for a second retouch technique whereby the tula was braced on an anvil during retouch using a technical gesture comparable to backing. Here we explore the kinematics and fracture mechanics involved in the freehand and anvil retouching techniques and propose that the anvil technique in making the Scarsdale 1 cache tulas was accomplished by novice stoneworkers. This, in turn, suggests that production of tools for exchange was a group-based endeavour and an opportunity for inducting novices into the stoneworkers’ community of practice.