High-resolution sedimentology and sequence stratigraphy of the Oxfordian-Kimmeridgian, Hanifa, Jubaila and Arab outcrops along Jabal Tuwaiq, Central Saudi Arabia

Abstract

The sequence stratigraphy of the Late Jurassic (Oxfordian to Kimmeridgian) of the central Arabia is based on outcrop measured sections. The sequence stratigraphic framework is extended eastward across the Arabian Basin through surface-to-subsurface gamma-ray correlations (550 km long to the east). It provides an insight into the development of an intrashelf basin in a large epeiric tropical platform. The outcrop depositional environments range from semi-arid shoreline to carbonate inner-lagoon and back-barrier lagoon. These formed an aggraded flat-topped platform with evident syndepositional differential subsidence. The Upper Jurassic successions are composed of several transgressive third-order sequences interrupted by short emersion sequence boundaries. The Hanifa Platform evolved from proximal argillaceous-limestone with low-faunal diversity to open-marine carbonate platforms with reef bearing and high-faunal diversity adjacent to a deep intrashelf basin in the subsurface. The Hanifa maximum flooding surfaces (MFS's) are placed in terrigenous-free open-marine carbonate sediments. The Jubaila-Arab-D is a conformable succession marked at the base by storm-influenced inner-platform grainstones with quartz sandstone, and proximal barren lime-mudstone. The Jubaila-Arab-D MFS is placed higher in the Arab-D reservoir in a backstepping of back-barrier high-energy reef facies. During sea-level highstand, the reef facies are gently prograding toward the Rimthan Arch leaving behind a restricted lagoon deposits consists of sabkhah/salina anhydride. These composite sequences are probably controlled by climatic driven eustasy, coupled with local tectonic disruption, as they have some similarity with other Tethyan sequence stratigraphy. For the first time, this outcrop study reveals a detailed and complete stratigraphic framework that subdivided the Upper Jurassic prolific petroleum systems into genetically related sequences that are not always obvious from subsurface data. The study allows the assessment of the Upper Jurassic tectono-stratigraphic events of the central Arabian Platform.