The new study, published in Scientific Reports, was conducted by a team of researchers from Norway, Spain and France. Together, they analysed the largest known collection of red and yellow mineral pigment fragments, commonly called ochre, dated to the Middle Stone Age (MSA, 300-40 000 years ago) and found at Porc-Epic Cave, Ethiopia. Their study shows that human groups visiting this site have gradually modified the techniques used to produce pigments, adapting to cultural or environmental changes that reduced their access to quality raw materials.
Innovative cultural traits
Francesco d’Errico says the new study is instrumental to understand the persistent and constantly evolving use of ochre 40,000 years ago in Ethiopia.
“Discoveries documenting the emergence of behavioural modernity in Africa have revealed that innovative cultural traits emerge in this continent at different times and in different regions. However, ancient sites that yielded archaeological collections large enough to precisely trace how these minerals were acquired, processed and used are rare”, explains d’Errico.
Key element in cultural development
“In order to understand the mechanisms and processes that have led to the development of modern cultures, we need to document and compare cultural trajectories in different regions. However, ancient sites that yielded archaeological collections large enough to precisely trace how these minerals were acquired, processed, and used are rare. Porc-Epic cave is, in this respect, a remarkable exception”, d’Errico explains.
“This cave features the largest African collection of ochre dated to the MSA in a region with few sites providing information on this key behavioural innovation. The findings from Porc-Epic therefore represent a unique opportunity for comparison with other African records”, d’Errico says.
Adapting technology to climate change
The cave site of Porc-Epic, Dire Dawa, Ethiopia, dated around 40,000 years ago, represents one of the few Palaeolithic sites that have yielded a continuous and extensive record of ochre use, spanning a period of at least 4,500 years. More than 40 kg of ochre (4213 pieces), 21 ochre processing tools, and two ochre-stained artefacts were found during the site excavation.
By analysing the chemical composition of ochre pieces found at the site and natural ochre from the cave’s surroundings, and studying the techniques used to process these rocks, the authors unveil how MSA inhabitants of the cave exploited mineral resources.
“Results show that they were able to predict the properties of different ochre types accessible in their environment, and gradually adapt their technology to changes in the availability of raw materials,” d’Errico says.
Emergence and evolution of complex cultures
He explains that a wide variety of ochre types were collected and brought to the site to produce ochre powder of different textures and shades, probably adapted to different symbolic or functional activities. However, the ubiquitous presence of red ochre, rich in hematite, throughout the occupations of the site, indicates that Porc-Epic inhabitants were specifically interested in this particular colour and mineral when collecting ochre pieces in the environment or exchanging them with neighbouring populations.
“The study of the Porc-Epic ochre record indicates the production of mineral pigment was deeply rooted in late East African MSA societies, but was also in constant evolution, during a period essential to our understanding of the emergence and evolution of complex cultures”, d’Errico says.