The need to have understood your local geology: nature and sources of materials used to manufacture stone artefacts at Olympic Dam, South Australia

Prehistoric stone technologists needed to understand the behaviour of the raw materials they worked with. The physical characteristics and geological sources of stone materials used by the people in the stony and sandridge desert at Olympic Dam in northeastern South Australia are described. Using data on the characteristics of stone artefact assemblages from a very large number of open archaeological sites, and on the distribution and characteristics of the geological sources, the different kinds of stone materials can be linked to patterns of artefact manufacture, use and discard in the Olympic Dam desert. The findings demonstrate the patterns of use of locally sourced stone types, including the preferred stone materials, and which of these were selected for making particular artefact types. Of the three main locally available stone materials (silcrete, quartzite and local chert) silcrete was the most sought-out material for making flaked artefacts and where not locally available it was transported over several kilometres. In contrast quartzite and local chert were generally used only where they were immediately available. Very fine (chert-like) silcretes and oolitic chert (only available in very small amounts) were used preferentially for making retouched artefacts. These findings can be extrapolated to a more extensive desert landscape stretching from Port Augusta in the south to Lake Eyre in the north.