[forces of nature] english - español - flash version - main page
[heading] [images]



Desert Rivers
In November 1981, members of the United States space shuttle Columbia returned with radar images of the eastern Sahara Desert. The image had peeled back 30 feet of the Selima Sand Sheet, a 39,000-square-mile plain, revealing the desert in its form 10 to 20 million years ago: as a land of flowing rivers, swamps, and lush savannas full of wildlife.

The ancient rivers flowed longitudinally, perhaps even linking the Niger and Benue Rivers with the Nile in the east. The images also revealed that water still flows through some of the valleys beneath the sands.

Other evidence also confirms the Sahara’s history. A 300-foot-high petrified coral reef exists across southern Morocco. A dinosaur graveyard has also been discovered near Agadez in Niger. Petrified tree trunks are scattered through the deserts in Algeria and Egypt. Humans only arrived in the area about 10,000 years ago, when the waters were already drying up. However, Neolithic tools have been discovered along the banks of the ancient waterways, including bone harpoons that settlers used to fish in the long-forgotten lakes of the region.

More recent evidence has been found on a high sandstone plateau 5,000 feet above the plains of southern Algeria, at Tassili-n-Ajjer in the heart of the desert. Here, hundreds of cave paintings as old as 9,000 years, show men in loincloths rounding up long-horned cattle, women with baskets on their heads, and archers pursuing antelope and hippopotami.

The paintings, tracing the development of the people, show pictures of early wild animals: buffalo, lions, antelopes, and elephants. Later images depict domesticated animals, two-wheeled war chariots, Nile boats, and camels. The painters stopped about 2,000 years ago, leaving the area that was rapidly becoming desert. Even today, the Sahara continues to expand, at a rate of more than three miles per year.


[ info ]: introduction - phenomena profiles - references

[ reality ]: current events - real life stories - interviews - quotations

[ interact ]: multimedia - simulations - classroom - activities - quizzes - message board - resources

[ general ]: about - win our award - awards we've won - guestbook - help - contact us - sitemap

[ forces ]: avalanches - droughts - earthquakes - flooding - fog & mist - forest fires - hurricanes - landslides - monsoons - phenomena - severe storms - snowstorms - tornadoes - tsunamis - volcanoes - windstorms - main page