Parts of a vast escarpment in the middle of the Sahara turns out to be an artifact of a prehistoric industry: ancient hominins creating tremendous amounts of stone tools and piling up discarded ones, say archaeologists from the University of Cambridge. It is the first known evidence of man changing his environment, whether he knew it or not, and on a massive scale, they say.
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A survey of the 350-kilometer long Messak Settafet escarpment, a massive outcrop of sandstone averaging 60 kilometers in width in Libya, found that the stone tools occur "ubiquitously" along it. The numbers are vast: the archaeologists estimate there are 75 stone artifacts per square meter.
With their actions the hominins modified the landscape, say the scientists, through the buildup of tools over millennia.
These first landscape architects were not Homo sapiens, though who they were is anybody's guess.
"The Messak sandstone, now in the middle of the vast sand seas of Libya, would have been a high quality rock for hominins to fracture - the landscape is in effect a carpet of stone tools, most probably made in the Middle and Upper Pleistocene," said Dr Robert Foley from the Leverhulme Centre for Evolutionary Studies at the University of Cambridge, who conducted the research with colleague Dr Marta Mirazón Lahr, in a statement.
There is no question that Man affects his environment, but usually one thinks of homo sapiens and his first stab at farming and urbanization. Archaeologists have shown, for instance, that the shift to early city life changed the natural fabric around the first settlements in Acre, for instance. And that was possibly as unwitting as the landscape modification now found in the Sahara. The study appeared yesterday in Plos One.
"The Messak Settafet is the earliest demonstrated example of the scars of human activity across an entire landscape; the effects of our technology on the environment may be considerably older than previously thought," Mirazón Lahr said.
Indeed: primitive hominins were making stone tools as much as two million years ago and more.
Speaking of making a mark, the Messak Settafet escarpment is also famous for prehistoric rock art, including stunning engravings of animals, dating to about 8,000 years ago.
Bulbs of percussion - check
The researchers sifted through all the stones per square meter, samples of course, not the entire 360-km escarpment , seeking clearly modified stones - evidence such as a 'bulb of percussion': a bulge or curved dent on the surface of a stone tool produced by angular blows. They found an average of 75 artifacts per square meter, ranging from simple flakes of stone whacked off boulders, to evidence of more sophisticated technologies, indicating that tools had wedged into stone in order split it.
Foley postulates that the hominins of ancient northern Africa were deeply dependent on their stone technology – and if so, that would have conferred a great advantage to anybody who knew where suitable raw materials could be found.
The extraordinary industry of stone working seems to have had ripple effects on the lifestyle in the region, not least because the hominins dug small quarrying pits, up to 2 meters in diameter and 50 centimeters in depth. These pits retain moisture after what rain there is in that area. That in turn would have attracted animals.
Indeed, the archaeologists say that in these pits, they found 'trapping stones': large stones used for traps, and ties for game and/or cattle, though these are younger than the stone tools – dating from some time during the last 10,000 years, certainly within the range of modern humans, not the beings that carpeted the escarpment with the artifacts of their industry.