TOOLMAKER: Kyle Brown recreates Stone Age tools with fire-heated silcrete.
Image: Science/AAAS
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Arrowheads and other Stone Age tools may not look like much to the untrained eye, but try making them yourself and you'll find out just how difficult it can be.
After struggling for years to replicate stone blades excavated in the southern tip of Africa, modern toolmaker Kyle Brown—like early humans before him—stumbled upon the missing ingredient: fire.
Most archaeologists have thought that humans developed pyrotechnology—the controlled use of fire—in Europe about 25,000 years ago. But Brown's discovery, published in Science today, pushes that date back to at least 72,000 years ago—and possibly as far as 164,000.
The new findings complement other discoveries, like shell beads and ochre pigments, revealing advanced technical capabilities in the earliest modern humans, who emerged between 150,000 and 200,000 years ago.
Beginning in 2006 Brown, a doctoral student at the University of Cape Town in South Africa, began hunting for stone outcrops that had the same silcrete (a hard material formed from dissolved silica) found in tools excavated from archaeological sites at Pinnacle Point. He and his colleagues made some 10 trips to the field, lugging the heavy rocks back to the lab and smashing them to try to recreate the stone blades. "I had a pretty high failure rate," he says. The stone never flaked off properly, and the tools he made were larger and thicker than the ancient tools. "We reached a point that we covered the landscape fairly well and we weren't finding any suitable rocks," he says.
The team, however, had recently excavated silcrete tools that had a glossy luster to them and looked a lot like heat-treated Native American tools they had seen before. In 2007 the researchers had also found a large hunk of silcrete embedded in ash. "Out of desperation," Brown says, "I put the materials in a fire." He buried them in a sand, built a fire on top, raised the temperature to 300 degrees Celsius over a period of about eight hours, and then cooked them for another eight. When he pulled the materials out of the sand, the rock flaked off easily, and had a glossy sheen that matched the silcrete artifacts.
Brown, 36, grew up in San Francisco and got his start making stone tools as a teenager. His father, a field biologist, took him on ecological studies in California's Napa Valley where he collected volcanic glass and tried to copy the arrowheads he found in the region. "I wasn't much good at that," he admits. Years later, as a student at the University of California, Berkeley, a toolmaker gave him instruction and he was hooked.
Now, Brown has something to teach the rest of us, something that earlier Homo sapiens figured out tens of thousands of years ago.
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7 Comments
Add CommentI just betcha the Gieco cavemen already new this.
Reply | Report Abuse | Link to thisTo me, this kind of discovery is what makes humans so much different from other species. Here we are, examining and analyzing artifacts made by people who lived so far back they might as well have been on another planet.
Reply | Report Abuse | Link to thisGiven that species are said to persist for an average of over 20 million years, it would behoove us to concentrate on persisting a lot longer than 200, 000 years. On that scale, we are just getting started.
I think stone tools are the least of the problems in modern anthropology. There are thousands of out-of-place artifacts that positively falsify this idea that our ancestors were somehow less intelligent (or indeed that they lived hundreds of thousands of years ago).
Reply | Report Abuse | Link to thisWould be interested to know how BuckSkinMan knows that the average species persists for 20 miilion years. My figures say its been about 6000-7000 years (on avaerage).
I think that alligators blow your numbers away don't they? Also what about birds or humans for that matter! How do you get your figures? 6000 or 7000 thousand years no no I think that you are surely wrong sir.
Reply | Report Abuse | Link to thisAlligators? :o)
Reply | Report Abuse | Link to thisI've yet to hear one speak let alone state its age.
> How do you get your figures?
I get my figures primarily from the humans who were there (you know witnesses - court of law type evidence).
I would also cite:
1. The persistence of collagen etc in Dinosaur and other fossil remains. (search: smithsonian blood dinosaur)
2. Helium in zircon (granite) - (search: RATE helium age)
3. The presence of C14 in diamonds
4. The unstabalised levels of C14 in atmosphere(search: Willard Libby C14 predictions)
5. Presence of short period comments (<10 000 years)
6. Presence of earth's electromagnetic field (its decaying and should be gone)
7. Presence of fossils (the rocks they are in should have eroded away by now)
Lots of stuff really... m'kay?
Well, Kyle in the photo, certainly doesn't *look* anywhere near 72,000 years old. Keep up the good work.
Reply | Report Abuse | Link to thisBut, then, these old tools--how exactly does Kyle *know* they were produced by HUMANS? Eh, say, Klingons-- on their last visit here. Romulans.
Damn Romulans. They never pick up their camp sites.
The truth hurts.
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