The evolution of late Quaternary stratigraphic sequences in the Burullus lagoon region of the north-central Nile delta, Egypt is determined by petrological analysis of radiocarbon-dated sediment borings. Shallow marine, lagoonal and fluvial deposits accumulated during the late Pleistocene, and delta plain to coastal facies during the Holocene (since about 7500 yrs B.P.). The latter sequence is characterized primarily by an irregular succession of delta plain deposits, i.e. distributary channel fill, marsh and lagoon. Complete coarsening upward sequences, formed by prodelta to coastal units and previously defined in the northeastern Nile delta, are not observed in this region. Long-term sediment accumulation rates for Holocene facies during the build-up of the delta range from about 100 to 300 cm/100 yrs. The location and ages of three Nile distributary channel systems are recognized by means of cores, from east to west: Sebennitic, Saitic, and Bolbitine/Rosetta. The mouth of the Sebennitic, which is oldest of the three, was located on what is now the inner to middle shelf. This would explain the absence of prodelta and delta-front sequences and a presence of a belt of medium- to coarse-grained sands extending seaward of the coast. The distribution in time and space of the Holocene facies is interpreted in terms of the interplay of factors controlling sedimentation, i.e. eustatic sea-level oscillations, climatic changes and land subsidence (minor in this region: 0.04 cm/yr). Of the three, sea-level changes dominate. Paleogeographic maps show, through a series of time slices, the changing configuration of this region during the past 30,000 years. Maps indicate the shifting channel systems and the major displacement of associated marshes and lagoons. This study suggests that, without the emplacement of coastal protection barriers and containment structures, an expansion of Burullus lagoon may be expected in the near future.
