DIAPIRIC FEATURES IN THE SOUTHEASTERN MEDITERRANEAN-SEA - POSSIBLE INDICATION OF EXTENSION IN A ZONE OF INCIPIENT CONTINENTAL COLLISION

Several types of diapiric structures were studied in the zone between the Nile deep-sea fan and the Eratosthenes seamount in the SE Mediterr anean Sea. The study discovered four stages in the structural evolutio n of the diapiric features, starting as a domal piercement structure, and developing into initial basin as seawater dissolution starts to ef fect the diapiric salt. Subsequently V-shaped, and then mature, U-shap ed basins formed as products of dissolution, sedimentary collapse and sediment deposition. The structures-both protrusions and depressions, are aligned along discrete lineaments, most of them trending NE-SW and a few-NW-SE. The NE-SW lineaments are probably a series of normal fau lts and the NW-SE ones seem to be strike-slip faults. The development of extensional structures on the underthrust edge of the African Plate , as it approaches the subduction zone, are commonplace in the Mediter ranean and elsewhere, and the occurrence of normal faults in this area is compatible with the intensive subsidence of the Eratosthenes Seamo unt in the Plio-Pleistocene. The lithostatic load of the Nile deep-sea fan could have contributed to the subsidence and thus enhanced the di apirism in the SE Mediterranean.