Talk:Tugen Hills
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[edit] Tugen Hills
The Tugen Hills consist of a 100 km long north-south oriented, westerly dipping, tilt block within the Gregory Rift Valley, Kenya. The summit of the hills at Saimo is at an altitude of 2,800 metres. Resulting from tectonic activity related to the global system of plate tectonics, the African Rift Valley has only three tilt blocks of such impressive dimensions, the Ruwenzoris in the Albertine Rift (Uganda-Congo), the Danakil Alps in Eritrea, and the Tugen Hills in Kenya. The uplift of the eastern edge of the Tugen Hills tilt block exposes 1,400 metres of Tertiary strata overlying Mozambique Belt gneisses of Proterozoic age (ca 650 million years). The Tertiary strata in the region span the period 17 million years to the present day, providing one of the most complete geological successions of this age known in Africa. The sequence is a series of volcanic and sedimentary deposits which accumulated within the rift depression as it formed, the volcanic eruptions often filling the rift to its brim and overflowing its shoulders from time to time. By 8 million years ago, sinking of the rift floor outstripped the rate of infilling, with the result that the blocking out of the main rift structures started to occur at that time, culminating in the present day relief that we associate with the valley. Relief from the summit of the Tugen Hills at Saimo to Lake Baringo in the east is about 1,400 metres.
The Tugen Hills rock sequence is a world class fossil repository, having yielded thousands of fossils of animals and plants from many different levels. These include remains relevant to the understanding of the origins of mankind, including the earliest known biped, Orrorin tugenensis, dated 6 million years. It is also the location of the earliest known hippos in the world, Kenyapotamus, an ancestor of the present day Hippopotamus.
The southern and central parts of the Tugen Hills are populated by the Tugen and their northern extremity is inhabited by the Pokot. In the more elevated parts of the hills agriculture is the main economic activity, whereas in the lower country to the north, east and west, pastoralism is the backbone of the economy. Soil erosion linked to deforestation is a pressing problem which is leading to immense changes in the landscape.
