The Middle Stone Age of Atlantic Africa: A critical review

Evidence of early Homo sapiens populations at the Atlantic coast of Africa remains relatively poorly known in relation to other regions of the continent. Nevertheless, available data across the continent provides a good starting point for current and future research investigations. The many sites known, documented and studied contribute in an increasingly way to the global understanding of the human emergence, including evidence of human evolutionary and technological advances, specific adaptations to diverse environments, the diffusion of Homo species and how humans interacted with each other from the “Early Stone Age (ESA)” through to the Middle Stone Age (MSA) from northern and southern Africa to the West. The differences of knowledge between the Atlantic coast in regard to other regions might be attributed to a number of reasons including but not limited to the history of scientific interest, site formation processes or economic, institutional and political constraints. However, the region received a renewed attention and funds that, combined with new methods and techniques, has been allowing an increased training of new researchers and the acquisition of high-resolution archaeological, paleoenvironmental and chronological data. Together, these inputs will reduce the differences of knowledge between the Atlantic coast and the Northern, Southern and Eastern Africa regions. The African Atlantic Coast represents more than 40% of the continent's perimeter, covering all Africa's climate zones, the hot arid environments, mountainous regions, and tropical rainforest could become relevant barriers for human mobility, but the shallow continental platform, and the great number of river basins allowed mobility between north and south coastal biomes into the continental interiors. These may have provided predictable patchy clusters of resources allowing human populations to thrive, enabling greater mobility and consequent diffusion of cultural traits, resources, and DNA. In this paper we review the record about the prehistory, paleoenvironments and paleoanthropological visibility and potentiality of Atlantic Africa

Hues of Namibia: characterization and provenience of Erongo rock art pigments.

International audienceErongo mountains, central Namibia, host numerous rock paintings. Archaeologists attribute them to San people, hunter-gatherers living in southern Africa for thousands of years. However, the lack of directly connected archaeological data maintains uncertainties about their chronology and attribution.Since 2007, an archaeological franco-namibian team has excavated the site of Leopard Cave (Erongo), and unearthed coloured materials and tools bearing pigments’ traces in layers dated back to approximately 3,000 BP. Together with the paintings on the site and its surroundings, these artefacts support the existence of a ”chaine opératoire” for rock art’s pigments.The study aims at providing new insights into the chronology and attribution of the paintings of Erongo mountains through analyses of rock art’s pigments and study of archaeological coloured materials’ provenience. In situ non-invasive analyses of the paintings, field surveys of geological sources followed with structural observations, elemental and mineralogical analyses of all the material collected should permit to reach these aims.As for the pigments’ characterisation, the first results confirm the use of iron oxides, carbon and various white materials. Besides, first observations point to a rather local procurement’s strategy with higher resemblances between the archaeological artefacts and the local geological sources than of the ones further away. Dating the carbonaceous pigments and correlation of rock art pigments with archaeological materials will provide a chronological milestone for southern African rock art. Paired with the study of the pigments’ provenience, it will provide key insights into the artists’ socio-cultural environment, therefore, confirming or not the nowadays attribution

Characterisation of colouring materials and rock art pigments in the Erongo Mountains (Namibia).

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First in situ pXRF analyses of rock paintings in Erongo, Namibia: results, current limits, and prospects

International audienceNamibia is one of the southern African countries hosting the richest rock art heritage, with thousands of rock paintings. Although numerous studies investigated their distribution, style, and possible meaning, few are known about the materials used to perform these paintings. Our in situ study aimed at identifying the diversity of pigments and alterations of some rock paintings in the northwestern part of the Erongo (Namibia). It relies on extensive pXRF analyses of 35 figures from eight rock art sites of the area. Despite common limits of in situ pXRF analyses, the extensive number of figures analyzed and the original data treatment that we performed pioneered the first scientific analyses of the pigments from rock painting sites in the Erongo Mountains. Furthermore, the study also confirmed the presence of iron oxide pigments on a portion of wall exposed during the excavations carried out at the archeological site of Leopard Cave and of possibly datable alterations over several paintings, paving the way to future chronological analyses of past tradition of rock paintings in Central Namibia

Data pretreatment and multivariate analyses for ochre sourcing: Application to Leopard Cave (Erongo, Namibia)

International audienceUsually referred to as ‘ochre’ or ‘pigment’ in archaeological contexts, ferruginous rocks were commonly exploited during the Later Stone Age in southern Africa. While ochre could lead to crucial inferences about socio-cultural behaviours of past populations, the provenance and the procurement strategies of this material in LSA contexts, as well as its association to rock art remain largely understudied. In the present study, seventeen ochre sources from five geological zones in north-central Namibia and 41 archaeological ochre pieces discovered in the stratigraphic sequence of the Later Stone Age site of Leopard Cave, Erongo Mountains - Namibia, were analysed by ICP-OES and ICP-MS/MS. Geochemical data coupled to data pre-treatment considerations and multivariate statistical analyses demonstrate that archaeological ochres were both collected locally and regionally from more distant sources. Beyond shedding new light on ochre provenance for rock art in north-central Namibia during the Later Stone Age, our data provide new insight into the mobility of past populations and the interactions existing between distinct rock art areas in north-central Namibia

Calcium oxalate radiocarbon dating: preliminary tests to date rock art of decorated open-air caves of Erongo Mountains in Namibia.

International audienceThe direct dating of rock paintings is not always possible due to the lack of organic carbon compounds in pigments, or because sampling from a heritage site is often restricted. To overcome these limitations, dating laboratories have to develop new approaches. In this study, we consider sampling calcium oxalate crusts covering the painted artworks as a way to indirectly date the rock art. This stratigraphic approach includes isolating and extracting pure oxalate from the crusts. The approach was tested on natural bulk accretions collected in the open-air sites of Erongo Mountains in Namibia. The accretions were separated into two phases (pure oxalate and the remaining residues) with a special pretreatment. This process removes carbonates through acidification (HCl 6N) and dissolves the oxalate into the supernatant, leaving the minerals and windblown organic compounds in the residue. The efficiency of the separation was checked on the two phases by FTIR analyses and by 14C dating and showed that pure oxalate powders were indeed obtained. AMS radiocarbon results of various accretions on the same art panels provided ages from modern periods to 2410 ± 35 BP. From these first results, more targeted sampling campaigns can be considered to provide a terminus ante quem for the rock art