Comparison between fan deltas in the Gulf of Suez, Egypt, and in the Gulf of Corinth, Greece

The aim of the present study is the recognition of the geological and sedimentological conditions which led in the formation of trapezoidal type fan deltas in linear extensional sub-basins located in the Mediterranean area and especially in Northern Africa and Southern Europe. For this purpose, two similar examples of such type of settings have been studied, in the Gulf of Suez (Egypt) and in Corinth Gulf (Greece), respectively. The development of these basins took place during Langhian (Suez Gulf) and Pleistocene (Gulf of Corinth) and was controlled by the presence of major marginal faults combined with transfer faults at the lateral extends of the basins. A critical factor for the sedimentation pattern into these basins is the presence of intrabasinal highs, trending parallel to the basin axis, which at the first stages of sedimentation acts as barriers, trapping the sediment and leading in the development of trapezoidal type fan deltas characterized by the absence of toe sets. Fine-grained sediment is transported outside the basin by strong currents, using transfer faults as pathways. In the Gulf of Corinth, the presence of intrabasinal highs and the limited space caused by this is the basic constraint for the development of trapezoidal type fan deltas, while in the Gulf of Suez, this has a secondary impact, as the main control factor is the viscosity and the bulk of sediment. Gradually, as the sediment accumulation is overstepping the intrabasinal high, more space is available for the evolution of the trapezoidal type fan delta to a Gilbert-type fan delta.