PALINSPASTIC AND CRUSTAL SETTING OF THE EASTERN MEDITERRANEAN

The nature and tectonic setting of the Eastern Mediterranean Basin are analyzed from geological and geophysical points of view. Palaeozoic and Mesozoic stratigraphy and palaeo-biogeography suggest that epicontinental Africa, Apulia and Arabia were united almost continuously during the entire Phanerozoic eon, prior to and after 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 a single Tethys ocean, north of the African-Apulian-Arabian palaeo-edge. Seismic reflection and refraction studies, together with magnetic and gravimetric measurements of the present Eastern Mediterranean Levantine crust, have revealed a sedimentary succession 13-14 km thick, which presumably includes Palaeozoic - Early Mesozoic strata overlying crust 8 - 12 km thick. Geological and geophysical re-evaluation suggests that the enormously thick sedimentary succession of the Levantine Basin covers a thinned crust of continental origin. The latter consists of Panafrican terranes, possibly including Infracambrian ocean-crust relies. Its ''oceanic''-like nature is presumably due to subcrustal thermal erosion. The possible existence of a western palaeo-high offshore the Levant Coast calls for reassessment of hydrocarbon exploration in the Eastern Mediterranean. The previously 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 western (offshore) highs. The passive extensional regime of the Gondwanan Eastern Mediterranean plate during most of the Phanerozoic eon ended with Late Cretaceous - Palaeogene Alpine compression of its margins, and the activation of the on- and offshore Levantinid Syrian Arc fold system.