Turkana Basin

The Turkana Basin in northern Kenya and southern Ethiopia (immediately adjacent to their convergence with the South Sudan and Uganda) is a site of geological subsidence containing one of the most continuous and temporally well controlled fossil records of the with some fossils as old as the Cretaceous. Among the Basin's critical fossiliferous sites are Lothagam, Allia Bay, and Koobi Fora. Much of the Turkana Basin today can be described as arid scrubland or even desert, but the center of the Basin holds Lake Turkana (at 3.3 degrees north latitude and 36.05 degrees east longitude), a major East African Rift and alkaline lake that supports a wide array of wildlife and a community of Turkana, Daasanach, Nyangatom and Pokot peoples.

Lake Turkana sits at the center of the Turkana Basin and is flanked the Chalbi Desert to the east, the Lotakipi Plains to the north, Karasuk to the west and Samburu to the south. Included within these regions are desert scrub, desert grass and shrubland, and scattered Acacia or open grasslands. Important towns within the Turkana Basin include Lokitaung, Kakuma, Lodwar, Lorogumu, Ileret and Kargi. The Turkana people inhabit the west of the Basin, the Samburu and Pokot people inhabit the south, and the Nyangatom, Daasanach and Borana Oromo peoples inhabit the north and east.

The oldest sedimentary records go back to the Cretaceous and are dominated by eastward flowing fluvial sequences draining into the Indian Ocean; later formations from the Oligocene and Miocene are characterised by similar fluvial regimes that are not however unified under a single geological group or system. Approximately 4.2 million years ago (Ma) the region experienced widespread and significant volcanism, associated with the Gombe basalts in the Koobi Fora formation to the east and with the Lothagam basalts further south; this event created a lake in the center of the basin and apparently established the modern, continuous depositional system of the Turkana Basin.

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