Graben Infilling in Gulf of Suez and Red Sea
P. F. Burollet
During the last 4 years, the French research group Genegass has completed geological and geophysical studies in the Red Sea and the Gulf of Suez. Neogene infilling of the basin is related with basement quality and volume of clastic supply, and inherited structural features are important to the development of Miocene rifting. The Neogene series may be divided into four major groups (Listed A-D), each limited by unconformities that seem to reflect the major stages of rifting.
(A) The lowermost formations begin with a conglomerate and are followed by a variegated unit of sand and clay. In the Gulf of Suez, especially on the eastern bank, these formations are marine. Along the Red Sea, tilted blocks may be capped by stromatolites, and the valleys between them are the site of shale and evaporite sedimentation (lower Miocene).
(B) The main extension phase results in an invasion of marine shales. The lower zones contain coarse clastics, and the high zones contain reefs and bioclastic limestone (late Burdigalian to early Serravallian).
(C) The middle to late Miocene corresponds to a regional basinward tilting. Stromatolites coat the slopes, and conglomerate fans are found in the lower zones. Evaporite sedimentation dominates; anhydrite is found on the borders, and in the basin, thick halite is overlain by a clastic series. Basement shoulders are uplifted.
(D) During the Pliocene and Pleistocene, the central part of the graben showed an important subsidence, and salt tectonism was active with diapirs and collapses.
AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.