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Stone 'Jigsaw Puzzles' Yield Clues About Mysterious Saharan Nomads

March 26, 1998
University Of Washington
A faint image of mysterious ancient Egyptian nomads living in the Sahara Desert has emerged from thousands of stone artifacts painstakingly collected and reassembled by a University of Washington archaeologist.

A faint image of mysterious ancient Egyptian nomads living in the Sahara Desert has emerged from thousands of stone artifacts painstakingly collected and reassembled by a University of Washington archaeologist.

The stone tools and fragments, which were scattered across the bleak but remarkably undisturbed sandy surface of the eastern Sahara, offer clues to a people who traversed the desert 5,500 to 8,000 years ago. Many of the stones were fashioned into blades used by these people to harvest wild grass seed that was then growing in the desert, according to Angela Close, a UW assistant professor of anthropology.

Close, who likens the process of fitting the rocks together to working on three- dimensional stone jigsaw puzzles, will discuss her findings Saturday afternoon at the annual meeting of the Society for American Archaeology in Seattle. Her research has led her to believe that these Neolithic people moved in specific pattern s through the desert and that they may have used cattle to transport sandstone boulders, the raw material from which they manufactured tools. She even thinks it is possible to trace the path of specific individuals from the sandstone artifacts left in their wake.

While Neolithic nomads in the central Sahara left behind a small record of their existence in the form of pictographs or rock paintings, little was known about the seasonal inhabitants of the eastern Sahara.

"There are essentially no human skeletal remains in that part of the Sahara and all we have is an occasional bit of pottery, a grinding stone or parts of ostrich egg shells that they used as bottles or containers," Close says.

She discovered the stone tools and fragments in the vicinity of a more contemporary well called Bir Safsaf that is located about 570 miles southwest of Cairo. The area was marginally more hospitable five to eight millennia ago when it was under the influence of a summer monsoon that brought perhaps as much as eight inches of rain annually. In that era the climate was comparable to today's Sahel, a region south of the Sahara which suffers from periodic severe droughts.

She says the site is remarkable because it is an undisturbed landscape. "Objects dropped on the desert thousands of years ago are still there. The area dried up 5,500 years ago and no one has been living there since. There was no looting. It's no Pompeii, but people did their thing at Bir Safsaf and then it froze in time."

The arid region around Bir Safsaf is essentially flat and barren. There are no exposed rock outcroppings in the area. The compacted sandy desert floor in much of the area is covered by nearly imperceptible ripples rather than the huge drifting sand dunes often associa ted with the Sahara. These ripples rise from three to six feet and can extend over areas as large as 100 by 500 yards. Between ripples are faint depressions where monsoon rainwater pooled and nurtured native grasses. It was the water and the grass that at tracted the nomads to the Bir Safsaf area, according to Close.

She observed that there were numerous rock fragments littering the landscape although the nearest sources of quartzitic sandstone are 10 to 13 miles away. Close marked off an area of approxi mately five-square miles and attempted to gather all of the rock inside it, eventually collecting more than 5,000 artifacts. They ranged in size from about one-quarter of an inch to small boulders weighing as much as l30 pounds. She also found a consider ably smaller number of artifacts made of chert, flint and chalcedony. The closest sources of these materials are about 50 to 90 miles distant.

When Close began the laborious task of trying to fit some of the sandstone fragments with others or the cores from which they were flaked, she began to detect curious patterns. She noticed that artifacts which fit together were not necessarily found on the same sand ripple. Nor were they scattered about the desert randomly. Instead they seemed to be located o n adjacent ripples, sometimes going back and forth between several of the rises. Eventually she pieced together numerous assemblages of artifacts, several of them made up of 30 or more pieces of sandstone that fit perfectly together.

From this she deduced purposeful movement patterns, noting that the nomads generally moved perpendicular rather than parallel to the sand ripples, and movement seems to be consistently towards the northwest or southeast. Movement also was over a somewhat limited distance, slightly less than 550 yards, which is the average distance between the ripples.

Close says the nomads seemed to go from one ripple to another rather than moving about aimlessly. "There was no reason for them to march five or six miles across the desert to find other food sources. They didn't have to travel very far, just to the next ripple that had grass," she explains. Occupation of the area was seasonal, lasting as long as there was water and grass to harvest, she adds. Then the nomads moved on.

The various sizes of the sandstone artifacts led Close to make some interesting speculations. She believes cattle were used to transport heavy pieces of sandstone across the desert.

"Some of the pieces are so heavy that they must have been carried on the backs of cattle. Ten miles is a long way for a person to carry something weighing more than a 100 pounds. And there are pictographs in the central Sahara showing people riding cattle," she says.

"At the same time, I'm looking at the movement of single small pieces of stone. It doesn't take more than one person to move them. I well may be looking at a person carrying a core from place to place, making tools as they were needed."

Aside from grass seed, which provided a meager food source and human nature, Close has no idea why people ventured into the eastern Sahara 8,000 years ago.

"We know people can adapt to harsh conditions and people learned how to exist at Bir Safsaf. We don't know why they lived in such a marginal environment instead of staying in the Nile Valley. As a species we go everywhere. Otherwise our human ancestors would have remained in East Africa."

Close's research was funded by the National Science Foundation.

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University Of Washington. "Stone 'Jigsaw Puzzles' Yield Clues About Mysterious Saharan Nomads." ScienceDaily. ScienceDaily, 26 March 1998. <>.
University Of Washington. (1998, March 26). Stone 'Jigsaw Puzzles' Yield Clues About Mysterious Saharan Nomads. ScienceDaily. Retrieved May 22, 2017 from
University Of Washington. "Stone 'Jigsaw Puzzles' Yield Clues About Mysterious Saharan Nomads." ScienceDaily. (accessed May 22, 2017).