The Great Rift Valley

Some 25 million years ago two continents, Africa and Eurasia, moving on their respective tectonic plates, collided and recoiled - shattering the earth's crust and creating the land feature known as the Great Rift Valley. The valley extends over 6,500 km from the Dead Sea in the north to Beira in the south and varies in width from thirty to ninety kilometres and in depth from a few hundred to several thousand metres, far below sea level

In Kenya the valley is deepest in the hundred and sixty kilometres that run north from Nairobi. Most of the lakes in the Rift, such as Lake Nakuru are shallow and having no outlet to the sea, are high in mineral content as the evaporation of water leaves salts behind.

Because the earth's crust is weakest where the valley is deepest, impressive volcanoes are associated with the Rift Valley including Mt Kilimanjaro (Tanzania), Mt. Kenya, and Mt. Meru (Tanzania). There are also Calderas such as the crater of Menengai near Nakuru where the whole mountain collapsed inward following volcanic action.