Eocene initiation of Nile drainage due to East African uplift

• We have developed a detailed dating of the Fayum Paleogene.
• The sedimentary units present record a dramatic change in sediment supply.
• The changes in sediment source correspond to uplift in East Africa.
• The development of Nile-type drainage can now be accurately dated.

The Late Eocene and Early Oligocene sedimentary succession in the Fayum, Egypt records the progressive development of northerly flowing Nile-type African drainage. New biostratigraphic dating of these units allows the calibration of the paleomagnetic record, the combination of dating methods enabling a detailed chronology of events to be studied. Between about 38 and 35 Ma there was a dramatic change in sedimentary regime and vast quantities of clastic material were transported into the area, smothering the underlying carbonate platform and initiating a stepwise progradation of clastic units. The sudden change in sediment availability coincides with the beginning of uplift and volcanic activity in the Turkana region of East Africa, cutting off preexisting easterly drainage from the middle of the continent. The Fayum succession therefore records the initiation of northerly drainage of central and eastern Africa, and the origins of the modern Nile watershed. The development of the current route of the Nile, with the incision of the current Nile Valley, was slightly later and related to mid Oligocene uplift of the Red Sea margins and Messinian base level fall.