High-frequency cycles and sequence stratigraphy of the lower Jurassic Marrat Formation, central Saudi Arabia

Well-exposed stratigraphic sections of the Toarcian siliciclastic/carbonate deposits of the Marrat Formation exposed at the Khashm adh Dhibi area (southwest of Riyadh city, Saudi Arabia) were studied for their facies associations and controls on sequence development. Seven facies associations from tide-dominated deltaic to inner carbonate ramp were recognized. Inferences based on facies relationships, characteristics of the sequence boundary and other characteristics suggest deposition of the Marrat Formation during three 3rd order sequences. These can be further classified into seventeen 4th order shallowing-upward small-cycle sets. Correlation of the recorded sequences boundaries within the Arabian/African Plates, Europe, and global schemes, reflect a strong eustatic control during the early Jurassic age with recognizable tectonic signature of the Gondwanland rift effects that caused a long period of regional uplift and non-deposition across the Triassic/Jurassic and early/middle Jurassic unconformities.