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The nature and tectonic setting of the Eastern Mediterranean Basin are analyzedfrom geological and geophysical points of view. Palaeozoic and Mesozoic stratigraphy and palaeo-biogeography suggest that epicontinental Africa, Apulia and Arabia were united almost continuousl-y during the entire Pharterozoic eon, prior to and a f e r the Early Triassic opening of the Mesozoic Tethys. The allochthonous ophiolite-bearing terranes. that were thrust over the edges of the Gondwanan plate, fit well within a palinspastic model of CI single Tethvs ocean. north of the African-Apulian-Arabian palaeo-edge.Seismic reflection and refraction studies, together with magnetic and gravinietric measurements of the present Eastern Mediterranean Levantine crust. have revealed a sedimentary succession 13-14 kin thick, which pt-esumably includes Palaeozoic -Early Meso,-oic struta oiyerlying crust 8 -12 km thick.Geological andgeophysical re-evaluation suggests that the enormously thick sedimentav succession of the Levantine Basin covers a thinned crust of continental origin. The latter consists of Panafrican terranes, possibly including Infracambrian ocean-crust relics. Its "oceanic "-like nature is presumably due to subcrustal thermal erosion. The possible existence of a western palaeo-high oflshore the Levant Coast calls for reassessment of hydrocarbon exploration in the Eastern Mediterranecin. The previouslv proposed "hinge belt" along the Levant Coast may merely represent the transition from the eastern platform to a graben that separates the eastern (onshore) from the w-estern (ofisshore) highs.The passive extensional regime of the Gondwanan Eastern Mediterranean plate during most of the Phanerozoic eon ended with h t e Cretuceous -Palaeogene Alpine compression (f its margins, and the activation of the on-and offshore Levantinid Syrian Arc fold svstern.

The constructive phase of the modern Nile Delta, as manifested in a 48-m section drilled east of the Suez Canal, commenced in very early Holocene times. Sands rich in marine fauna were deposited in the littoral zone and the shoreline was more than 20 km landward of its present-day position. Subsequently, clays and silts were dumped from the Nile distributaries and the marine faunal spectrum became very limited and brackish. Later in early and middle Holocene times the sediments deposited were rich in freshwater, delta-plain diatoms and pollen and in allochthonous fern spores from the tropics, indicating proximity of a distributary mouth. The middle part of the section (22.5-17.5 m) is very poor in faunal and floral remains; pollen grains from sabkha vegetation are abundant. The environment, which seems lagoonal and slightly hypersaline, is related to the sea regression in middle Holocene times. Euryhaline pelecypods, dating from about 3000 yr B.P., are abundant around the 8-m depth. Upward, there is an increase in pollen grains from sabkhas; the section is poor in diatoms and those present are mostly euryhaline and lagoonal. Allochthonous spores derived from the nearby Pelusiac Branch are abundant. Between 3000 and 2000 yr B.P. the constructive phase of the modern delta terminated and winnowed sands began accreting in front of the delta plain.

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