Geological Structure of the Deep Eastern Mediterranean Sea (East of 25 Degrees E)

L. Montadert, L. Sage, J. Letouzey

The deformation fronts of the Cyprus arc and the Mediterranean ridge, extending from the Turkey-Syria boundary to north Cyrenaica, are the southernmost superficial expression of the convergence between the Eurasian and African plates. They separate the Eastern Mediterranean deep basin into two different structural units: (1) A thrust belt, northward, with the presence of Cenozoic sedimentary basins which could be considered piggy-back basins (Iskenderun, Adana, Cilicia and Antalya basins). These basins, filled by 4,000 to 6,000 m of Cenozoic sediments, lie on a substratum composed of south-vergent nappes emplaced between the Late Cretaceous and the late Miocene. (2) A foreland area, southward, where the thick Herodotus and Levantine sedimentary basins, relatively undeform d, lie on the passive and subsident African continental margin initiated during Late Triassic or early Liassic time.

Due to the still-active collision between the thrust belt and the Erathosthenes seamount, Cyprus was uplifted and today represents the emerged part of the deformation front.

During the Messinian, with the isolation of the Mediterranean Sea, evaporitic deposits including a salt layer (sometimes more than 2,000 m thick) were widely distributed into the Iskenderun, Cilicia, Antalya, Levantine, and Herodotus basins. In these basins, the Messinian sedimentation was directly controlled by basin topography.

The interpretation of multichannel seismic profiles recorded east of 25°E let us establish a synthetic structural map and regional geologic cross sections. Front of nappes, thrusts, faulted and folded belts, evaporites and salt extension, diapiric zones, onshore geology, reactualized bathymetry, and isopachs of the salt base-sea bottom interval are figured on the map at the 1/2,500 scale.

AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.