Sophisticated Stone Age ancestors

Ancient Africans used ochre for a wide range of purposes, from decorative or symbolic to purely functional, a new study reveals. The findings indicate that people of the Middle Stone Age led lives of considerably greater complexity than previously assumed.

Ochre is made from rocks containing iron oxides, which yield red or yellow powders when processed. A trio led by archaeologist Daniela Rosso from the University of Bordeaux, France, set out to explore its uses among people who used a site in Ethiopia, known as the Porc-Epic Cave, around 40,000 years ago.

The team used X-ray, spectroscopy and microscopy techniques to analyse 21 well-preserved ochre processing tools, such as grindstones, and two ochre-stained artefacts, uncovered in the Middle Stone Age layer of the cave.

The use of ochre for decorative or symbolic functions has been disputed by some authorities, but Rosso’s research, published in PLoS One, revealed the powders had not one but many applications in Mesolithic society.

“Ochre is a common feature at Middle Stone Age sites and has often been interpreted as a proxy for the origin of modern behaviour,” the researchers write.

“However, few ochre processing tools, ochre containers and ochre-stained artefacts from MSA contexts have been studied in detail.”

By studying the tools, researchers could ascertain varying degrees of hardness and wear patterns, whether they had been used to pound or grind the ochre, and if a binding agent was used.

The analysis of the objects revealed different processes had been used to create a variety of ochre colours and textures, suggesting the material had multiple uses.

Powder from grindstones fashioned from relatively soft rocks such as limestone or sandstone had been mixed with some ochre samples to lighten its colour.

Grindstones made of harder rocks, such as basalt and quartzite, were also used, and these would have affected the granularity of the ochre produced.

Such wide variance in production methods suggests ochre was made for an equally wide range of functions.

“Fine, clayish sorted ochre powder is more suitable for cosmetic or symbolic activities such as body painting,” the researchers explain.

“Whereas mixed grain size ochre would be more adapted to utilitarian activities such as hafting.”

One of the two artefacts collected might be an ancient stamp, made to reproduce a semi-circle of red on animal or human skin.

“A round stone bearing no traces of having been used to process ochre is half-covered with residues, as if it had been dipped in a liquid-ochered medium to paint the object or to use it as a stamp to apply pigment to a soft material,” the paper reports.

This discovery, taken as evidence of symbolic ochre use, is the earliest known painted object from the Middle Stone Age.

Interestingly, the artefacts and grindstones, along with the majority of the 4,213 ochre-producing rock fragments collected by Russo and her team, were all discovered in a small part of the cave, suggesting a dedicated area “devoted to ochre processing”.