Chance find unearths Stone Age cemetery

The tiny skeletal hand jutted from the sand as if beckoning the living to the long-dead.

For thousands of years, it had waved unheeded in the most desolate section of the Sahara desert, surrounded by the bones of hippos, giraffes and other creatures typically found in the jungle.

A chance discovery by American scientists has led to the unearthing of a Stone Age cemetery that is providing the first glimpse of what life was like during the still-mysterious period when monsoons brought rain to the desert and created the "green Sahara."

The more than 200 graves explored indicate that, beginning 10,000 years ago, two populations lived on the shores of a massive lake, separated by a 1,000-year period during which the lake dried up.

Among the scientists' surprising discoveries has been a burial of a mother and two children with fingers intertwined, a find that puts a human face on the little-known people who enjoyed a brief visit to an Eden in what is normally one of the most forbidding places on Earth.

The first to settle the area was a group of tall, powerfully built hunters, gatherers and fishermen called the "Kiffian," University of Chicago paleontologist Paul Sereno said at a news conference Thursday in Washington, D.C., at the National Geographic Society, which helped finance the research.

The group who followed the Kiffian was a physically smaller band of pastoralists called the "Tenerian," who relied on fishing and hunting but also herded cattle, he said.

In addition to the graves, researchers found a massive collection of the remains of meals, tools, pots and other artifacts — the detritus of everyday life.

The findings were published Thursday in the online journal PLoS One and in the September issue of National Geographic magazine.

"Desert within a desert"

The Sahara has been a desert for untold millennia. But about 12,000 years ago, a wobble in the Earth's orbit and other factors caused Africa's seasonal monsoons to shift slightly north, bringing rains to the Sahara and greening it from Egypt in the east to Mauritania in the west.

About 8,000 years ago, the rains retreated, leaving the region once again arid and abandoned. A thousand years later, the rains returned for two millennia, before permanently retreating.

The newly discovered site, called "Gobero" after the Tuareg name for the area, lies deep within Niger's Tenere Desert, a large region within the still-larger Sahara that's known to Tuareg nomads as a "desert within a desert." The site lay unobserved and untouched because it was literally "in the middle of nowhere," Sereno said. "There is absolutely no reason for anyone to go there."

Sereno had a reason — a nearby table of 110-million-year-old sandstone "that has more dinosaurs in it of high quality than any other rock in the continent of Africa."

In 2000, Sereno and colleagues were on one of their forays in which they would travel as far as they could in one day, looking for new dinosaur bones.

"We were at the end of our rope," Sereno said, nearly out of water and ready to turn around, when he spotted a stone formation sticking up in the distance and decided to go a little farther.

When they got there, they found animal bones scattered on the surface, exposed by the weather. Photographer Mike Hettwer wandered, then rushed back to the group.

"I found some bones," he said. "But they're not dinosaurs. They're human."

The hand, probably belonging to a child, stood out amid the flat landscape, its finger blackened but intact. The researchers saw parts of dozens of human skeletons, including jawbones with teeth and skullcaps filled with sand.

Sereno and the group "tiptoed in and saw a dozen skeletons" but didn't disturb anything, he said. "I realized we were in the green Sahara.

"Part of discovery is finding things that you least expect," he said. "When you come across something like that in the middle of the desert, it sends a tingle down your spine."

They left the site alone for three years while Sereno continued dinosaur excavations.

Eventually, he excavated for three seasons, before being frozen out of the area in 2007 and 2008 because of clashes between the Tuareg and government troops.

One of the experts he took with him was archaeologist Elena Garcea of the University of Cassino in Italy, a pottery expert who has spent three decades working in Northern Africa.

"I have never seen such an exceptional site as Gobero. It is actually eight sites where people not only buried their dead but actually lived, as well," Garcea said.

She immediately spied small potsherds inscribed with a pointillistic pattern characteristic of a nomadic people, the Tenerian, who lived 4,500 to 6,500 years ago. But she quickly found others that had a wavy, zigzag pattern characteristic of the Kiffian, the hunters and gatherers who lived 8,000 to10,000 years ago.

That dichotomy continued throughout the excavations. One group of graves contained individuals who averaged more than 6 feet tall, with some as tall as 6 feet, 8 inches. These individuals, the Kiffian, were folded in tight burial arrangements with their knees against their chests and arms at their sides.

The mark of rodents

One odd but significant find was the discovery of rodent bite marks on some skeletons. In archaeology, such evidence of rodent activity can indicate that a community settled in one place for long enough to attract pests and build a sizable dumping ground.

The researchers used radiocarbon dating to determine when these ancient people lived there. Even the most recent were some 1,000 years before the building of the pyramids in Egypt.

Accompanying the graves were remains of elephants, giraffes, hartebeests, warthogs and pythons, as well as abundant 6-foot-long, 300-pound Nile perch, which indicated the presence of a deep lake at the site during the period.

The team found harpoon points and fishing hooks as well as stone tools associated with the Kiffian. Their bodies were heavily muscled and robust, suggesting that they were active fishermen.

In other graves, bodies were shorter and slender, characteristic of pastoralists who fished less and herded more. The same animals, as well as cattle, were associated with them, but the fish were smaller catfish and tilapia, suggesting that the lake was shallower during their occupation.

The most touching grave was the burial triptych. A young woman was lying on her side. Pollen under her body suggests that she was placed on a bed of flowers. Lying on their sides facing her were two young children, their fingers interlocked with hers, leaving a tangle of bones.

"I think nobody is going to doubt that this is an intentional burial. These people are posed," Sereno said. He speculated all three might have drowned together.

One girl in another grave had an upper-arm bracelet carved from a hippopotamus tusk, the first such find on a female. A male was buried sitting on the shell of a turtle, and another was interred with his head resting on a clay vessel.

It is not clear how they died. Two arrowheads were associated with the woman's body, Sereno said, but there is no evidence of trauma on her skeleton. The team is running DNA tests to confirm that they are mother and children.

The Associated Press, The Washington Post and the Chicago Tribune contributed to this report.