Microfacies architecture and depositional history of the Upper Jurassic (kimmeridgian) Jubaila Formation in central Saudi Arabia

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 ferruginous calcareous quartz arenite, ferruginous sublitharenite, and burrowed dolomicrite. In the mid-ramp setting, there were changes from lateral facies in the Riyadh and the Wadi Huraymila areas to carbonates characterized by sandy lime-mudstones, dolosparie, peloidal olitic packstones, and coralline bioclastic wackestones to packstones. 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 lime-mudstones, dolomitic marls, and pelletal bioclastic wackestones 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.

Automated summary

The Upper Jurassic Jubaila Formation in central Saudi Arabia exhibits laterally coeval environments from the southwest to the northeast, showing characteristics of inner, mid-, and outer ramps. The distribution of microfacies in the Jubaila Formation is vertically arranged into four 3rd-order cycles, which correlate laterally overall the studied area, but are influenced by oscillations in eustatic sea-level during deposition.