ABSTRACT
The Oko shear zone (OSZ) is a late Precambrian (~700 – ~560 Ma) NNW-to NW-trending deformational belt in the central Red Sea Hills of the Sudan. It left-laterally offsets the ~800 – ~750 Ma old NE-trending Nakasib suture by about 10 km. The Oko deformation started as an E-W-directed flattening which produced N-trending, tight to isoclinal, upright folds. This culminated in initiation of NW-trending left-lateral and NNE-trending right-lateral conjugate set of strike-slip faults. The NW-trending set dominated and resulted in development of E- and W-verging thrusts associated with a flower structure. The OSZ bears gross similarities to other post-accretionary structures of the Arabian-Nubian Shield (ANS). In this work, it is suggested that the post-accretionary structures of the Shield are the product of collision of the ANS to the E against the Nile craton to the W at around 670 – 610 Ma.
