Abstract
Central Arabian Mountain Tuwaiq Plateau, south Riyadh City underwent geologic work, including calibrated, filtered, geo-referenced and ortho-rectified synthetic aperture radar (SAR) imageries of the ERS-1/2 and ENVISAT satellites. The Jurassic Mountain Tuwaiq Plateau shows cuestas with flatiron geomorphology dipping gently, which is eroded by an eastward dendritic drainage pattern atop Mountain Tuwaiq, which pours southward running into the Wadi Hanifah valley. The E-W Druma, Nisah, Awsat, Bu’ayja, Rufa’a and Mugarah grabens of Central Arabia are superposed on the plateau’s geologic and geomorphic features and appear to be part of the Sahaba strike-slip fault. The graben system has turned the N-S Mesozoic beds into escarpments, with them dipping inwardly towards the north and south and forming a multiple horst and graben. The overlying Cretaceous rocks were transtensionally deformed, and they crop out next to the Jurassic sequence. The transtensional system has also thrown the upper Cretaceous and Paleogene rocks down atop the lower Cretaceous rocks. The overall drainage pattern is an eastward running centripetal pattern that is overprinted by a longitudinal parallel system. Moreover, the Wadi Hanifah valley was displaced by Wadi Laha sinistral fault. The Central Arabian graben system of Mountain Tuwaiq Plateau may fit in the transtensional horsetail splay tectonic landform and damage zone area of the Wadi Sahaba transform fault at the termination mechanism. This intra-plate setting and continental interior may relate to the collision of Arabian and Eurasian plates, in which the transform fault represents Mountain Zagros’ thrust belt westward escape structures in the Arabian hinterland area.