Geochemical characterization of archaeological ochre at Nelson Bay Cave (Western Cape province), South Africa

摘要

A considerable ochre record exists for both the Middle Stone Age (MSA) and Later Stone Age (LSA) of southern Africa. Despite this, little work has been done on these assemblages and ochre source exploitation patterns are not well understood for either time period. Ochre, due to its heterogeneous nature, has often been thought not suitable for characterization and sourcing analysis. However, much success has been achieved sourcing Australian ochre using a variety of techniques. Similar analysis has rarely been carried out on South African ochre deposits and assemblages. This study examines the utility of ochre sourcing using a Middle-to-Later Stone Age ochre assemblage from Nelson Bay Cave on the Robberg Peninsula, South Africa. Archaeological ochre samples were subjected to both powder X-ray diffraction (XRD) and particle-induced X-ray emission (PIXE) in order to determine chemical and mineralogical composition. Using these techniques, several probable chemical groups were identified within the assemblage. This study suggests that it may be possible to match archaeological ochre fragments to specific geological deposits or regions of the landscape. In the future, such work will help to develop an understanding of ochre exploitation and transport in the Middle to Later Stone Age.