Red Balloon rock shelter Middle Stone Age ochre assemblage and population's adaption to local resources in the Waterberg (Limpopo, South Africa)

Ochre has been found at many Middle Stone Age sites throughout southern Africa. Much work has been done to document these iron-rich raw materials, their modifications and their implications for past communities' behaviours, skills and cognition. However, until recently few works focused on the Middle Stone Age Waterberg ochre assemblages. The paper presents the ochre assemblage recovered at Red Balloon rock shelter, a new Middle Stone Age site on the Waterberg Plateau. The site preserves Middle Stone Age occupations dated around 95,000 years ago. Scanning electron microscopy observations, portable X-ray fluorescence spectroscopy and infrared spectroscopy characterization document the presence of four ochre types. The MSA ochre assemblage recovered is mainly composed of specularite and specular hematite similar to the ones of Olieboomspoort and North Brabant. Microscopic observations and infrared analyses of soil sediment and of post-depositional deposits found on the ochre pieces show that this raw material specificity is of anthropic origin and not the result of post-depositional processes. Optical and digital observations of the archaeological assemblage and its comparison with a preliminary exploratory experimental one highlight the use of abrasion and bipolar percussion to process the ochre pieces at the site. The results point to the know-how and skills of the Middle Stone Age populations who inhabited the Waterberg region around 95,000 years ago. This raises the question of whether the specificities of the Waterberg ochre assemblages correspond to populations' adaptation to the local mountainous mineral resources and the existence of a regional ochre processing tradition.