Monday, May 21, 2012
South African archeologists said early humans knew chemistry
Xinhua | October 15, 2011 09:32
By Agencies
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South African archeologists have made an important discovery suggesting that early humans had an elementary knowledge of chemistry about 100,000 years ago, Business Day newspaper in Johannesburg reported on Friday.

The findings by researchers from the University of the Witwatersrand in Johannesburg were published in the international journal Science on Friday.

They tell of an ochre-rich mixture in use at the time and provide a benchmark in the evolution of metal processing.

The site was discovered at Blombos Cave, 300 kilometers (km) east of Cape Town.

The excavation team was headed by Christopher Henshilwood, a research professor at the Institute for Human Evolution at the University of the Witwatersrand.

He find comprised two abalone "toolkits" that contained items such as ochre, bone, charcoal, grindstones and hammer stones.

Henshilwood said the mixture was possibly used for decoration, painting and skin protection 100,000 years ago.

He added that the grinding and scraping of ochre to produce a powder for use as a pigment was regarded as common practice in Africa and the East only after that period.

"Ochre may have been applied with symbolic intent as decoration on bodies and clothing during the Middle Stone Age," he said. "This discovery represents an important benchmark in the evolution of complex human cognition."

He said it shows that humans had the conceptual ability to source, combine and store substances that were then possibly used to enhance their social practices.

The term "ochre" is used by archaeologists to describe earth or rock containing red or yellow oxides or hydroxides of iron.

The ochre would have been collected from the closest source at least 20 km away.

Using a technique called optically stimulated luminescence dating, the researchers found the quartz sediments in which the ochre containers were buried to be about 100,000 years old.

Business Day said this method of dating measures the amount of radiation absorbed over time by buried grains of sand, which can then be converted to measure their age.

Henshilwood said the recovery of the toolkits adds evidence for early technological and behavioral 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."

News of the discovery quickly spread on social networking site Twitter.

The specimens are being exhibited at the South Africa Museum in Cape Town from Friday.


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