Stratigraphic Evolution of the Turkana Basin, Kenya and Ethiopia

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The Turkana Basin of Kenya and Ethiopia has long been known as a critical locality for the understanding of vertebrate evolution in East Africa. The geologic record of the basin spans a broad range, including Cretaceous through Holocene sediments with intercalated volcanics. Cretaceous through Oligocene history has yet to be characterized, but Miocene to Holocene strata are well- known. They record the stratigraphic evolution of the basin from a volcanically active, localized sediment trap, to an integrated fluvial basin with periodic lacustrine phases, and finally to a structurally-controlled rift basin. Research over the past decade on the context of vertebrate evolution in the basin has greatly altered our perspective on the history of the region and development of the East African Rift. Within the stratigraphic and temporal framework established for vertebrate studies, it is now possible to examine in detail the evolution of the region in terms of its volcanic, tectonic and sedimentary history, and to reevaluate the history of geologic processes in this portion of Africa. We intend to focus our attention on the unstudied southern portion of the Turkana Basin, and to investigate exposures in the Loiyengalani region, the Chalbi Desert, on Mt. Kulal, and in the Suguta and Kerio Valleys. Understanding of the geologic record from these regions is critical to evaluating the history of major geologic events in the basin, including basin integration, hydrographic connections, and structural development.