Olduvai Gorge

 

 

Olduvai Gorge. Located in the Great African Rift. The Great Rift Valley. This runs over 6,500 km from the Dead Sea in the north to Beira in the south. The cracking formed two sets of highland regions separated by a valley which varied in width from thirty to ninety kilometres and in depth from a few hundred to several thousand metres, far below sea level. The earth's crust dropped as the recoiling twin faults pulled it apart. The effect has been likened to the key stone of an arch dropping as the side pillars collapse.

In East Africa the Western Rift contains a se ties of the deepest lakes in the world (up to 1,560 metres deep). Between its eastern wall and the west wall of our Great Rift is a huge depression largely filled by Lake Victoria which is only some 200 metres deep but is in surface area the second largest mass of water in the world after Lake Superior. It receives more rainfall (about 200 to 250 centimetres a year) in the middle than anywhere near its edges.

In Kenya the earth's upward thrust was most powerful in the hundred and sixty kilometres that run north from Nairobi. Consequently this is where the valley is deepest. The Rift has no outlet to the sea. Its lakes tend to be shallow and have a high mineral content as the evaporation of water leaves the salts behind. Lake Magadi is almost solid soda. Lakes Nakuru and Elmenteita also contain substantial soda flats. Lakes Turkana and Baringo are fresh enough to maintain a rich fish life while Lake Naivasha, supplied by freshwater springs deep under the earth, supports an astonishing variety of bird, fish and plant life.

The formation of the Rift Valley is in geological terms still continuing. It is, surprisingly, slowly widening and eastern Africa may, in millions of years time, split off to form a new continent. The original violent crack that caused the Rift naturally weakened the earth's crust most where the valley was deepest. It is, therefore, in this area and radiating from this main valley that other major volcanic activity produced numerous volcanic formations which in turn produced the sudden contrasting upheavals which give Kenya such beautiful landscapes. The most impressive of the volcanoes associated with the Rift Valley turmoil are Mt Kilimanjaro, Mt. Kenya (which was once higher than Mt. Kilimanjaro, which is geologically younger), Mt. Meru, Mt. Elgon, the Virunga Volcanoes and the Crater Highlands . But the Aberdares, the Chyulu and Taita Hills, the Ngong Hills (near Nairobi) and Longonot and Suswa, which both tower over Lake Naivasha, while less dramatic, are all beautiful and more accessible.

Olduvai Gorge is a 30 miles long gash in Tanzanias Serengeti Plain. Between 1,9 and 1,2 million years ago a salt lake occupied this area. From 1,2 million to 600,000 years ago fresh water streams and small ponds laced the area.

Olduvai Gorge was a basic place for Louis Leakey family excavations which gave many fossil specimens of human ancestors. There were also many artifacts found in the gorge.