Analyses of 40,000 year old ochre finds in Ethiopia's Porc-Epic Cave point to symbolic use

The EU-funded TRACSYMBOLS project, which closed in 2015, investigated archaeological sites in South Africa for early use of symbols by homo sapiens, examining painting kits, spear points, beads and ostrich egg shell engravings. They also studied the usage of the reddish iron-rich rock, ochre. And it was to ochre that members of the project team have more recently returned.

View of Porc-Epic Cave [Credit: A. Herrero]

Recently writing in the open-access journal PLOS ONE members of the TRACSYMBOLS project team explain that ochre is commonly found at Middle Stone Age (MSA) sites. The state in which it is often found, with pieces modified through grinding and scraping to produce red powder along with ochre-stained objects such as lithic and bone tools, lead researchers to treat its presence as an indicator of modern symbolically mediated human behaviour.

In this latest research the team analysed the largest known East African MSA ochre collection at Porc-Epic Cave, Ethiopia. It comprised a haul of 40 kg of ochre, which spanned a period of at least 4,500 years and dates back to around 40,000 years ago.

To understand how the ochre had been processed and so learn something of its use, the team analysed 3,792 pieces using visual characterisation, microscopy, surface texture analysis, morphological and morphometric analysis, while also replicating grinding techniques.

Modifications on ochre pieces: (A, B) Striations produced by grinding PE102 and PE987. (C, D) Incisions 
produced by scraping/scoring PE306 and PE1419. (E) Smoothed areas on PE3067. (F) Pits produced 
by a pounding action on PE931 (OPT21)

A key finding was that the cave dwellers seem to have acquired, treated, and used the same types of ochre over this 4,500-year period. The researchers conclude that, given the quantities discovered, usage indicates the ‘expression of a cohesive cultural adaptation, largely shared by all community members and consistently transmitted through time.’

Some ochre pieces evidenced the usage of grindstones over time, most likely to produce powder which fits knowledge about powder’s use in physical adornment, such as body painting, though a more utilitarian purpose has not been ruled out.

The original TRACSYMBOLS project was set up to explore the emergence of key cultural innovations in Africa and Europe between 160,000 and 25,000 years ago. In Africa its archaeological excavations were concentrated in the southern region of Western Cape Province, South Africa.

Ochre pieces from Porc-Epic Cave [Credit: Daniela Eugenia Rosso et al. PLOS ONE]

The team complemented the archaeological approach with palaeoclimatic indicators which reflected the evolution of temperature, vegetation and fire regimes. When this information was used by computational modelling the combination afforded a richer understanding of the link between past human adaptive systems and the environments in which they evolved.

The findings led the team to conclude that homo sapiens were already using symbols 75,000 years ago, and possibly as far back as 100,000 years. The timing is significant as it suggests that by the time homo sapiens were leaving Africa, generally thought to be around 80,000 – 60,000 years ago, they were already ‘modern’. It had previously been thought that the culturally and technologically significant advancements of homo sapiens originated in Europe 40,000 years ago. Furthermore, this modernity is likely to have contributed to their subsequent dominance across Europe.

Source: Cordis [July 11, 2017]