Evolution from continental rifting to passive margin in northeast Arabia; evidence from exploration wells in the United Arab Emirates

The continental lithosphere stretches and ultimately splits during extension resulting in rifted margins that may transform into passive margins depending on their mechanical and thermal state. The heating and thinning of the continental lithosphere during the rifting process causes contemporaneous subsidence that accumulates syn-rift deposits. The extension of the lithosphere plays a critical role in plate dynamics as it occurs both in oceans and continents. The passive margin of northeast Arabia provides a unique geodynamic system for the full development of a continental rift into a mature passive margin. Here, this margin is buried under 5-7-kilometer-thick foreland basin sequences. The basement beneath the passive margin sequences has not been imaged by seismic nor sampled by deepest exploration wells. Therefore, the evolution remains enigmatic due to the lack of resolving data and the deep burial cover. This signifies the need for a powerful innovative approach to characterize the lithospheric stretching that occurred and its ever-since evolution. Here we integrate seismic reflection profiles and 3D seismic volumes, with compiled biostratigraphic data from 260 exploration wells to remove the sediment and water loads effect to acquire terms due to tectonic mechanisms. Seismic stratigraphy loosely identifies the top of the passive margin sequences based on the seismic reflection configurations, reflector geometry, and reflection termination. The bottom of these rifted sequences however cannot be determined. Additionally, the structural configuration of the rifting that occurred was severely obscured by the Ophiolite emplacement in the Late Cretaceous and the collision along the Zagros suture in the Miocene. As result, the faults were highly inverted negatively due to the emplacement of significant orogenic loads and crustal shortening. On the basis of backstripping, we suggest the occurrence of at least two phases of continental rifting during the Permian-Jurassic time spanning combined age of ~147 Ma. The initial phase commenced in the Early Permian (ca. 272 Ma) and is linked to the initial Tethys opening. The final rifting phase took place in the Late Jurassic (ca. 160 Ma) and is associated with the culmination of the continental break-up of Gondwana. The anomalous tectonic subsidence coupled is related to the heating and thinning that caused the thermal contraction of the crust. A uniform depth extension model implies that the lithosphere was thinned to 88% during the initial rifting and by 1% during the final rifting based on modeled stretching factors of 1.13 to 1.27 and 1.11 to 1.17, respectively. Spatial modeling of the stretching factors yielded critical insight into the lithospheric and crustal necking that occurred in the area. The identified evolution of northeast Arabia’s passive margin and its implications contributes to efforts in determining the hydrocarbon prospectivity of deep plays in the area.