The discovery of whale fossils from Eocene strata in the Fayum Depression has provoked interest in the life and lifestyle of early whales. Excellent outcrop exposure also affords the dataset to develop sedimentological and stratigraphic models within the Eocene strata. Previous work generally asserts that the thick, sand-rich deposits of the Fayum Depression represent shoreface and barrier island successions with fine-grained lagoonal and fluvial associations capping progradational successions. However, a complete absence of wave-generated sedimentary structures, a preponderance of thoroughly bioturbated strata and increasingly proximal sedimentary successions upwards are contrary to accepted models of the local sedimentological and stratigraphic development. This study considers data collected from two Middle to Upper Eocene successions exposed in outcrop in the Wadi El-Hitan and Qasr El-Sagha areas of the Fayum Depression to determine the depositional affinities of Fayum strata. Based on sedimentological and ichnological data, five facies associations (Facies Association 1 to Facies Association 5) are identified. The biological and sedimentological characteristics of the reported facies associations indicate that the whale-bearing sandstones (Facies Association 1) record distal positions in a large, open, quiescent marine bay that is abruptly succeeded by a bay-margin environment (Facies Association 2). Upwards, marginal-marine lagoonal and shallow-bay parasequences (Facies Association 3) are overlain by thick deltaic distributary channel deposits (Facies Association 4). The capping unit (Facies Association 5) represents a transgressive estuarine depositional environment. The general stratigraphic evolution resulted from a regional, tectonically controlled second-order cycle, associated with northward regression of the Tethys. Subordinate cycles (i.e. third-order and fourth-order cycles) are evidenced by several Glossifungites-ichnofacies demarcated discontinuities, which were emplaced at the base of flooding surfaces. The proposed depositional models recognize the importance of identifying and linking ichnological data with physical-sedimentological observations. As suchwith the exception of wave-generated ravinement surfaces -earlier assertions of wave-dominated sedimentation can be discarded. Moreover, this study provides important data for the recognition of (rarely reported) completely bioturbated sand-dominated offshore to nearshore sediments (Facies Association 1) and affords excellent characterization of bioturbated inclined heterolithic stratification of deltaic deposits. Another outcome of the study is the recognition that the whales of the Fayum Depression are restricted to the highstand systems tracts, and lived under conditions of low depositional energy, Sedimentology (2010) 57, 446-476 low to moderate sedimentation rates, and (not surprisingly) in fully marine waters characterized by a high biomass.

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2016: Bioerosion in the Miocene Reefs of the northwest Red Sea, Egypt. Lethaia, 49, Macroborings provide detailed information on the bioerosion, accretion and palaeoenvironment of both modern and fossil reefs. Dolomitized reefal carbonates in the Um Mahara Formation exhibit an outstanding example of spatially distributed, well-preserved bioerosion structures in tropical to subtropical syn-rift Miocene reefs. Ten ichnospecies belonging to five ichnogenera are identified; three belonging to the bivalve-boring ichnogenus Gastrochaenolites, three attributed to the sponge-boring ichnogenus Entobia, and four ichnospecies assigned to three worm-boring ichnogenera Trypanites, Maeandropolydora and Caulostrepsis. The distribution of the reported borings is strongly linked to the palaeo-reef zones. Two distinctive ichnological boring assemblages are recognized. The Gastrochaenolites-dominated assemblage reflects shallower-marine conditions, under water depths of a few metres, mostly in back-reef to patch-reef zones of a back-reef lagoon. The Entobia-dominated assemblage signifies relatively deeper marine conditions, mostly in reef core of the fringing Miocene reefs. These ichnological assemblages are attributed herein to the Entobia sub-ichnofacies of the Trypanites ichnofacies. This ichnofacies indicates boring in hard carbonate substrates (such as corals, rhodoliths, carbonate cements and hardgrounds) during periods of non-sedimentation or reduced sediment input. □ Egypt, Miocene reefs, Red Sea, Um Mahara Formation. Zaki A. Abdel-Fattah [zabdelfattah@gmail.com], and Ehab M. Assal [ehab.assal@

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