Journal of African Earth Sciences ( IF 1.603 ) Pub Date : 2020-11-19 , DOI: 10.1016/j.jafrearsci.2020.104076 Mohamed Khalifa; Khaled Al-Kahtany; Sherif Farouk; Abdelbaset S. El-Sorogy; Abdullah Al Qahtani
The Upper Jurassic Jubaila Formation in central Saudi Arabia exhibits laterally coeval environments from the southwest to the northeast. These coeval environments involve inner, mid-, and outer ramps. The inner ramp occurs at the Al Haddar section in the extreme southwest and consists of mixed clastic-carbonate facies and are represented by intercalations of calcareous quartzenties, sublitharenites, and burrowed dolostones. In the mid-ramp setting, there were changes from lateral facies in the Riyadh and the Wadi Huraymila areas to carbonates characterized by pelletal wackestones, coralline algal packestones, and oolitic pelletal wackestones/packestones. These are intercalated with sandy lime-mudstones that might be deposited in highly agitated environments. The outer-ramp setting occurred in the farther northeast Al Uyaynah area. It is characterized by reduced thickness and is composed of pelletal bioclastic wackestone, lime-mudstones, and pelletal lime-mudstones with thin beds of dolomitic marls. The lateral and vertical microfacies distribution in the Jubaila Formation are arranged vertically into four 3rd-order cycles that are correlate laterally overall the studied area, which are overprinted by oscillations in eustatic sea-level during the deposition of Jubaila Formation.