Riaan F. Rifkin

Assessing the efficacy of red ochre as a prehistoric hide tanning ingredient

Over the past four decades, several functional hypotheses have been proposed for archaeological ochre. Ochre has been shown to have antiseptic properties and to inhibit the bacterial production of collagenase. These qualities are repeatedly cited to support the hypothesis that red ochre was used to preserve or ‘tan’ animal hides in prehistory. If clothing made from hides was worn by Homo sapiens in Africa, then hide tanning could have formed a part of the trend towards increasingly modern technological and social advances during the Middle to Late Pleistocene. This paper presents the results of an experimental study exploring the efficacy of ochre as a treatment for making unprocessed animal hide resistant to putrification and desiccation. This study shows that certain types of ochre do preserve animal hide. The implications of this technological advance for the emergence of human behavioural modernity in Africa are discussed.

Evaluating the Photoprotective Effects of Ochre on Human Skin by In Vivo SPF Assessment: Implications for Human Evolution, Adaptation and Dispersal

Archaeological indicators of cognitively modern behaviour become increasingly prevalent during the African Middle Stone Age (MSA). Although the exploitation of ochre is viewed as a key feature of the emergence of modern human behaviour, the uses to which ochre and ochre-based mixtures were put remain ambiguous. Here we present the results of an experimental study exploring the efficacy of ochre as a topical photoprotective compound. This is achieved through the in vivo calculation of the sun protection factor (SPF) values of ochre samples obtained from Ovahimba women (Kunene Region, Northern Namibia) and the Palaeozoic Bokkeveld Group deposits of the Cape Supergroup (Western Cape Province, South Africa). We employ visible spectroscopy, energy-dispersive X-ray fluorescence (ED-XRF), X-ray diffraction (XRD) and granulometric analyses to characterise ochre samples. The capacity of ochre to inhibit the susceptibility of humans to the harmful effects of exposure to ultraviolet radiation (UVR) is confirmed and the mechanisms implicated in the efficacy of ochre as a sunscreen identified. It is posited that the habitual application of ochre may have represented a crucial innovation for MSA humans by limiting the adverse effects of ultraviolet exposure. This may have facilitated the colonisation of geographic regions largely unfavourable to the constitutive skin colour of newly arriving populations.

Engraved art and acoustic resonance: exploring ritual and sound in north-western South Africa

At a hill-top site in the Korrannaberg, where there is a water source and a sandy arena embraced by a rocky ridge, the author persuasively evokes a lively prehistoric ritual centre, with rock gongs, reverberating echoes, dancing and trance.