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7th Middle East Geosciences Conference and Exhibition
Manama, Bahrain
March 27-29, 2006
Structural
Styles in Central and Eastern Saudi Arabia
Saudi Aramco, Dhahran, Saudi Arabia, phone:
966-3-873-4585, [email protected]
Located on opposite margins of the West Rub' al Khali basin, two
structural
trends of the Central Arabia and Eastern Arabia
share a general north-south
structural
orientation and similar transpressional
structural
styles in the Carboniferous
Hercynian Orogeny. Multiple seismic profile and map geometry criteria (Harding, 1990) are used to identify the magnitude
and direction of strike-slip faulting for the two trends.
Transpressional structures in Central Arabia, interpreted by Simms (1994), have been validated by recent 3D seismic surveys. The long, linear N-S trending master faults, of Infracambrian age, form an integral part of a right-lateral transpressional fault system with many distinctive coeval, en echelon flanking folds. Many oil fields are associated with these structures. Right-lateral slip of a minimum of 0.5 kilometers along individual fault is observed based on offsets of preexisting faults.
Recent 3D seismic interpretation of the
structural
trend on the east basin margin indicates a left-lateral transpressional
system, with much smaller strike-slip component. Most fault planes are sub-parallel but discontinuous along the strike, as
opposed to their through-going and solitary counterparts in Central Arabia to the west. However, some amount of strike-slip
movement can be inferred, based on the following evidence: (1) relatively linear fault traces and steeply dipping fault planes
offsetting the top of basement; (2) relatively symmetrical shape of a few folds; (3) acute angular relationship of a few coeval,
flanking folds to the causative fault trace; and (4) change of fault dip direction with depth.