The Fayum Oasis and surrounding areas in Egypt include a number of exceptionally rich and important fossil vertebrate sites. These include the Wadi Al-Hitan World Heritage Site, made famous by the abundance of archaeocete whale remains, and the site BQ-2 with its diverse terrestrial mammals, including primates. Despite the importance of this area, the stratigrapby is poorly understood and there has be little agreement in the dating of the fossiliferous units. This is in large part due to the extreme diachroneity of some of the rock units and paucity of biostratigraphically useful fossils within the shallow water facies. Platform carbonates are overlain by condensed open marine mudstones of the Gebannam Formation. These span the Bartonian-Priabonian boundary, with a diverse offhore marine fauna being present throughout, including marine mammals. Four units of shoreface sandstone of the Birkel Qarun Formation overlie and partly pass into the Gehannam Formation. The lowest of these sandstone units is dated to nannofossil zone NP19/20, and hence 'mid' Priabonian, and contains the oldest archaeocetes described from the region. Diverse fossils, including abundant whales, are present throughout the Birket Qarun Formation, but these are especially concentrated at the top of the lowest sandstone (lowstand systems tract) and in the transgressive lower part of the third sandstone and its lateral equivalent within the Gehannam Formation (transgressive systems tract). The overlying Qasr el Sagha Formation is a very rapidly deposited deltaic/lagoonal complex. Tidal channels from two to over 40 metres deep are present throughout. The lower part of this formation is still in nannofossil zone NP19/20. INterchannel deposits contain a fully marine, but probably shallow water, assemblage. Larger channels also include deeper water elements near the base, with transported terrestrial and quasimarine elements being present within the uppermost part of a small channel fill at quarry BQ-2. The transition to the non-marine units above is sharp but conformable and coincides with the base of the Oligocene. The clastic succession indicates the initiation of Nile-type drainage and coincides with the uplift of East Africa, preventing drainage to the east. It is likely that clastic successions in the Qattara Depression and Libya can be related to the same sedimentological episodes. This is largely based on, and dedicated to, the work of Chris King, who passed away earlier this year.
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