The project involved two main components: the geochemical analysis of silcrete raw materials collected from across northwest Botswana and northeast Namibia, and equivalent analyses of waste manufacturing flakes sampled from the collections of artefacts held at the National Museum, Gaborone. The results of the two sets of analyses were compared statistically using canonical discriminant analysis to assess the degree of match between artefact and raw material chemistries.
Initial raw material analyses indicate that silcretes in different parts of the Kalahari have contrasting chemistries, with samples from Lake Ngami, the Boteti River, Xaudum Valley and Okavango River (Figure 2 below) falling into distinct geochemical domains. This appears to be driven by varying proportions of rare earth elements within the silcrete host sediments.
Results of geochemical fingerprinting indicate that the peoples who occupied the four MSA sites were clearly aware of regional resource availability, anticipated a need, and procured silcrete for tool manufacture from the Boteti River and Lake Ngami, between 220 and 295 km distant. This is an unusually long distance of raw material transport for this time period. This suggests that these people made two conscious decisions. First, despite having ready access to local stone they chose to import silcrete. Second, they opted to use silcrete from south of the Okavango Delta rather than silcrete of equal quality from much closer.
The reason for MSA peoples making these choices is, as yet, unresolved. This procurement strategy could be purely economic or may be related to territorial or symbolic factors. However, knowledge of the landscape, locations of silcrete quarries and movement routes between outcrops and occupation sites must have been communicated. It is difficult to imagine this communication being possible without facilities for in-depth planning and advanced language.
The results of the project are already having impact. Information about patterns of resource procurement at the Tsodilo Hills sites have been incorporated into training sessions provided for local guides at the World Heritage Site, and are now being shared with international visitors.