Monday, April 2, 2012

A Million Years of Fire

One of our newest technologies has just shed new light on one of our oldest.

When did our human ancestors learn to control and use fire? Armed with the latest high tech tools, an international team of researchers has pushed the date back to 1 million years. That’s 300,000 years earlier than previous unambiguous dates.

The massive Wonderwerk Cave is in northern South Africa on the edge of the Kalahari. Previous excavations have shown extensive human occupation. Using the new techniques of micromorphological analysis and Fourier transform infrared microspectroscopy (mFTIR), researchers analyzed cave sediments at a far more detailed level than possible before.

Caption: This is a panoramic view of the entrance to Wonderwerk Cave, South Africa. Credit: H. Ruther. Usage Restrictions: None

In the cave sediments researchers found bits of ash from plants along with fragments of burned bone. Did the wind blow burning debris into the cave? The evidence—collected about 100 feet from the current opening of the cave—supports the conclusion that the fire burned in the cave. Also part of the proof: the surrounding surfaces are discolored.

”The analysis pushes the timing for the human use of fire back by 300,000 years, suggesting that human ancestors as early as Homo erectus may have begun using fire as part of their way of life," anthropologist Michael Chazan said in a press release from the University of Toronto.

According to the paper, "Through the application of micromorphological analysis and Fourier transform infrared microspectroscopy (mFTIR) of intact sediments and examination of associated archaeological finds— fauna, lithics, and macrobotanical remains—we provide unambiguous evidence in the form of burned bone and ashed plant remains that burning events took place in Wonderwerk Cave during the early Acheulean occupation, approximately 1.0 Ma. To date, to the best of our knowledge, this is the earliest secure evidence for burning in an archaeological context."

Caption: Interior of Wonderwerk Cave. Images courtesy of M. Chazan.

"The control of fire would have been a major turning point in human evolution," says Chazan. "The impact of cooking food is well documented, but the impact of control over fire would have touched all elements of human society. Socializing around a camp fire might actually be an essential aspect of what makes us human."

How important are fire and cooking for human evolution. A recent book, Catching Fire: How Cooking Made Us Human by Richard Wrangham, argues that cooking is essential to our humanity. Now in the paper published on April 2, the team concludes that its study “is the most compelling evidence to date offering some support for the cooking hypothesis of Wrangham.”

Their work is published as “Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape Province, South Africa,” in the April 2, 2012 issue of the Proceedings of the National Academy of Sciences.

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