Deep structures and seismic stratigraphy of the Egyptian continental margin from multichannel seismic data
Published:January 01, 2010
Laurent Caméra, Alessandra Ribodetti, Jean Mascle, 2010. "Deep structures and seismic stratigraphy of the Egyptian continental margin from multichannel seismic data", Evolution of the Levant Margin and Western Arabia Platform since the Mesozoic, C. Homberg, M. Bachmann
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Regional multichannel seismic reflection (MCS) profiles across the Egyptian continental slope, offshore the Nile delta, were recorded during the MEDISIS survey (conducted in 2002 on board the R/V Nadir). The results of this survey allow an interpretation of the overall structure and evolution of this passive continental margin. The MCS data were processed using an amplitude preserving pre-stack depth migration technique, which has the advantage of providing a quantitative, and geometrically correct, image of seismic horizons. Well-defined reflecting events allow the identification of three main seismic units. The upper unit (a 7 km thick) is interpreted as the post-rift sedimentary cover of the margin; it includes an undisturbed Middle Cretaceous to Upper Miocene sedimentary pile, covered by thick Messinian (latest Miocene) salt-rich layers and by Pliocene to Quaternary sediments, locally intensively deformed by gravity tectonics. The underlying intermediate acoustic unit (6 km thick on average) is interpreted as the Mesozoic syn-rift sedimentary cover of the margin; the end of the last rifting event is marked by a strong angular unconformity, tentatively of Aptian age. The lower unit may correspond to the thinned continental crust of Africa (12 km thick on average in the study area) and its pre-rift cover. Its base is identified by strong, discontinuous reflector packages about 23–25 km below sea floor, interpreted as indicative of the Moho.
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Evolution of the Levant Margin and Western Arabia Platform since the Mesozoic
This volume combines original data in various fields from the offshore Levant Basin and adjacent continental slopes and platforms. The first group of papers document the tectonic structures and sedimentological patterns associated with the development of the Levant Basin. They identify the successive rifting events from the Late Palaeozoic to the Early Cretaceous, followed by a moderate tectonic activity. The contribution of external factors like global sea-level and climate changes to the sedimentation processes during the Mid-Cretaceous is discussed in the second set of papers. The final group presents new kinematics and age constraints on the Late Cretaceous to Neogene tectonic phases and discusses the relationship of the structures with the closure of the Neo-Tethys and separation of the Arabia plate. This collection of research papers demonstrates new concepts on the opening and crustal thinning of the Levant Basin and gives updated interpretations of the latter tectonic structures of the Levant.