Characterising pigments on 30000-year-old portable art from Apollo 11 Cave, Karas Region, southern Namibia
As an unambiguous indication of complex cognitive capacity, representational art presents explicit evidence for modern and symbolic human behaviour. The only examples of African figurative art dating to the Late Pleistocene comprise seven stone plaques recovered from Apollo 11 Cave in the Huns Mountains, southern Namibia. The plaques derive from a single anthropogenic layer dated by radiocarbon (14C) accelerator mass spectrometry (AMS) and optically simulated luminescence (OSL) methods to c. 30000years ago. We present the results of digital (CIE) L*a*b* colourimetric and portable energy dispersive X-ray fluorescence (ED-XRF), Raman spectroscopic and Fourier transform infrared reflectance (FT-IR) analyses of the pigments present on the plaques. These results provide the earliest direct evidence, in Africa, for the preparation of pigment-based paint-like mixtures and their application to create prehistoric art. Our research shows that in the creation of the depictions on the plaques, the artists used black pigments derived from manganese and charcoal, red pigments likely derived from ocherous shale and white pigments possibly derived from ostrich eggshell. Additionally, these plaques provide unique evidence for the combined use of mineral- and carbon-based pigment 'crayons' during the African Middle Stone Age.