Implications of ochre source heterogeneity for ochre provenance

Indigenous Australians and First Peoples around the world use ochre as their ancestors have for tens of thousands of years and continue to shape contemporary uses of pigment in rock art, pigment-treated objects, and in ceremonial use. Provenance studies are a key approach to answer questions on ochre source attribution and cultural exchange of this significant material in the archaeological past. Ochre source sites (geological formations) are inherently complex, and each have their unique geological and cultural history which can be characterized as a unique site ‘fingerprint’. However, If the factors around intra-site variation over time are not addressed adequately, further conclusions on the ochre source ‘fingerprint’ characterization, archaeological material provenance, and cultural use may potentially be biased and therefore affect the archaeological interpretations. This manuscript addresses key questions around the relationship of intra-site variability and ochre provenance via multi-proxy analysis of Ma:ko, an Australian Aboriginal cultural sedimentary ochre source. The results provide insight into understanding the potential effects on ochre fingerprint due to intra-site variation, sampling and seasonality, with intra-site variation causing more potential variation on the geochemical and mineralogical fingerprint than seasonality. This study also provides a best practice approach for examining intra-site implications for provenance, archaeological interpretation, and source use through time for ochre sites globally.