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Monday, June 7, 2010

Stone Age Color, Glue 'Factory' Found

Stone Age Color, Glue 'Factory' Found
The color and glue trade could have been a blossoming industry some
58,000 years ago.

By Jennifer Viegas | Thu Jun 3, 2010 07:00 AM ET

The Stone Age version of successful businessmen like Steve Jobs and
Bill Gates might have been involved in the color and glue trade.

A once-thriving 58,000-year-old ochre powder production site has just
been discovered in South Africa. The discovery offers a glimpse of
what early humans valued and used in their everyday lives.

The finding, which will be described in the Journal of Archaeological
Science, also marks the first time that any Stone Age site has yielded
evidence for ochre powder processing on cemented hearths -- an
innovation for the period. A clever caveman must have figured out that
white ash from hearths can cement and become rock hard, providing a
sturdy work surface.

"Ochre occurs in a range of colors that includes orange, red, yellow,
brown and shades of these colors," project leader Lyn Wadley told
Discovery News. "Yellow and brown ochre can be transformed to red by
heating them at temperatures as low as 250 degrees Celsius (482
degrees Fahrenheit)."

Wadley, who authored the study, is a professor in the School of
Geography, Archaeology and Environmental Studies and in the Institute
for Human Evolution at the University of the Witwatersrand. She said
ochre has been found on bone awl tools probably used for working
leather, so it is possible that the ancients sported colorful leather
clothing and other leather goods.

Red-hot leather clothing is still found in stores today, but the
probable wearers then were a far cry from today's fashion elite.

Ochre is derived from naturally tinted clay that contains mineral
oxides. In addition to coloring objects, it makes a compound adhesive
when mixed with other ingredients, such as plant gum and animal fat.

"This glue would have attached stone spear or arrowheads to hafts, or
blades to handles for cutting tools," Wadley explained.

Ochre can also be used as body paint and makeup, as a preservative and
as a medicinal component, so it could have served many different
functions during the Stone Age.

Wadley analyzed the ochre "factory" at the large Sibudu rock shelter
north of Durban in KwaZulu-Natal, South Africa. The site consisted of
four cemented hearths containing the ochre powder. The cement
workstations could have held grindstones and/or served as storage
receptacles for the powder, according to Wadley, who also excavated
about 8,000 pieces of ochre in the area.

She believes the natural material was collected just over a half a
mile away from the site, where it would have been heated and ground or
just ground directly onto coarse rocks.

Francesco d'Errico, director of research at the National Center of
Scientific Research at the University of Bordeaux, said pigment
material is found in bits and pieces at various early sites. However,
not much was known in detail before about how it was processed and

Based on the nature of the cemented ash and the geology of the Sibudu
site, d'Errico believes that people 58,000 years ago intended to
produce large quantities of red pigment in a short time frame.

He now thinks ochre pigment was a "fundamental constitute of Middle
Stone Age culture, and that its production likely involved the work of
several members of the group."


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