Structural Evolution Along the Suez Rift

B. Colletta, P. Lequellec, J. Letouzey, I. Moretti

A three-dimensional study of the structure of the Suez rift was carried out using field and subsurface data in an attempt to determine the role of transverse faults and the longitudinal evolution of the rift. The structure of the Gulf of Suez area is governed by normal faults and tilted blocks whose crests constitute the main target of exploratory wells. The fault pattern consists of two majors sets of trends: (1) longitudinal faults parallel to the rift axis and created in an extensional regime where ^sgr₃ was trending east-northeast-west-southwest, and (2) transverse faults with a north-south to north-northeast-south-southwest dominant trend. The transverse faults are inherited passive discontinuities, while most of the longitudinal faults were created during Neogene times in a pure extensional regime. Both sets were simultaneously active, producing a zigzag pattern and rhombic-shaped blocks. The transverse faults act as relays between major normal faults. Cross profiles show that all the major blocks are tilted in the same direction. However, the tilt direction changes: north and south of the rift the blocks tilt eastward, and in the center they tilt westward. To the north the change of dip is accommodated by a graben-type "twist zone" without transverse faulting, at least in the Neogene series. To the south the change of dip is accommodated by a more complex structure involving both a major transverse fault and a horst-type "twist-zone." Balanced cross sections show that the tilt angle and the amount of extension increase from north to sout , while the width of the blocks decreases. Minimum values for the amount of opening range between 5 km to the north to about 20 km to the south.

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