SOUTH AFRICA: A 100,000-year-old workshop

An ochre-rich mixture that was possibly used for decoration, painting and skin protection 100,000 years ago has been discovered stored in two abalone shells at Blombos Cave, 300 kilometres east of Cape Town. The discovery represents an important benchmark in the evolution of complex human thought.

"Ochre may have been applied with symbolic intent as decoration on bodies and clothing during the Middle Stone Age," says Professor Christopher Henshilwood from the Institute for Human Evolution at the University of the Witwatersrand in Johannesburg.

Together with an international archaeology team, Henshilwood discovered the processing workshop where a liquefied ochre-rich mixture was produced. The findings were published in the journal Science.

The two coeval, spatially associated toolkits were discovered in situ and the kits included ochre, bone, charcoal, grindstones and hammerstones or grinders. The grinding and scraping of ochre to produce a powder for use as a pigment was common practice in Africa and the Near East 100,000 years ago.

"This discovery represents an important benchmark in the evolution of complex human cognition in that it shows humans had the conceptual ability to source, combine and store substances that were then possibly used to enhance their social practices," Henshilwood says.

"We believe the manufacturing process involved the rubbing of pieces of ochre on quartzite slabs to produce a fine red powder. Ochre chips were crushed with quartz, quartzite and silcrete hammerstones and combined with heated crushed mammal-bone, charcoal, stone chips and a liquid, which was then introduced to the abalone shells and gently stirred. A bone was probably used to stir the mixture and to transfer some of the mixture out of the shell."

The quartz sediments in which the ochre containers were buried were dated to about 100,000 years using Optically Stimulated Luminescence dating. This is consistent with the thermo-luminescence dating of burnt lithics and the dating of calcium carbonate concretions using uranium-series dating methods.

"The recovery of these toolkits adds evidence for early technological and behavioural developments associated with humans and documents their deliberate planning, production and curation of pigmented compound and the use of containers.

"It also demonstrates that humans had an elementary knowledge of chemistry and the ability for long-term planning 100,000 years ago," Henshilwood says.