Sedimentation Patterns in Southern Gulf of Suez Rift
Stephen K. Perry, Steven Schamel, John L. Smale
Surface and subsurface mapping in the southern Gulf of Suez, primarily in the Gemsa Plain and contiguous regions, delineates sedimentation patterns that persisted throughout extensive tectonism, subsidence, and large sea level variations. Proximal clastic facies reflecting uplift and erosional stripping of rift shoulders and tilt-block crests interfinger with a succession of normal marine and evaporitic units during basin filling, while sedimentation kept pace with subsidence.
The Gemsa Plain subbasin comprises a half graben abutting the border fault of the southwest-dipping Esh el Mellaha tilt block on the southwest and rising onto Gebel Zeit, a stripped tilt-block crest. To the north, the basin laps onto the structurally high Ras Shukheir platform. Two cross-cutting wadis, draining northeastward, provide primary clastic input. Wadi Dara cuts a low-lying topographic high north of the Esh el Mellaha and Wadi Dib crosses the northern Esh el Mellaha, draining the basin to its southwest. During the early Miocene, normal marine conditions prevailed, with both wadis building large fan-delta complexes whose coarse clastics interfinger with basinal shales and marls eastward and ultimately thin onto the Zeit high. In the later Miocene, the same basic pattern persis ed, with marine evaporites largely substituting for marls and fine clastics. Today, large fan complexes still dominate sedimentation. The basin facies patterns have remained essentially unchanged throughout rifting, although lithologies changed through time in response to the interaction of local vertical movement and eustatic sea level variation.
AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.