The Jiddah Transfer Zone: Understanding Initial Red Sea Rift Deformation and Its Exploration Impact
Hussein G. Aly Fouda, Paul G. Nicholson, Kent Norton, Robert E. Tubbs, and Andrew Jollands
Area of Exploration, Saudi Aramco, Dhahran, Saudi Arabia
Across the Red Sea region on both the African and Arabian shields, successful exploration requires a thorough understanding of the pre-rift rocks and the structural controls on their preservation.Present-day distribution of pre-rift fluvial to shallow marine clastics of Early Eocene, Paleocene, Cretaceous, and pre-Carboniferous age is controlled by both depositional paleogeography and the subsequent post-depositional structural history.
Transfer zones in the Red Sea region formed during the initial rift phase. Their location and trend is related to the underlying Neoproterozoic basement fabric. During the initial rifting phase in the Late Eocene to Oligocene, pre-rift sediments were preserved in hanging wall blocks formed by extensional reactivation of two major sets of sub-vertical lineaments: “Najd” shears trending (azimuth) 125-130o, and faults trending N-S. Along both the African and Saudi Arabian coastal plains, pre-rift sediments are found in hanging walls located in the ‘SW quadrant’ of the intersection of these two sets of basement lineaments.
A newly identified “Jiddah transfer zone” in Saudi Arabia follows the underlying Neoproterozoic basement trend observed in the surrounding basement rocks. Field observations and 2D seismic interpretation along the Saudi Arabian coastal plain from Midyan southward to the east of Jeddah show the pre-rift sediments dipping regionally to the northeast, however, from the Aasfan area south to the north of Wadi Fatima, the pre-rift section regionally dips to the southwest. South of Wadi Fatima, these rocks once again return to a regional northeast dip. Discovery and analysis of the Jeddah transfer zone will enable more accurate structural mapping of pre-rift fault blocks in the subsurface, together with more accurate prediction of potential syn-rift (Miocene) reservoirs.
AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery