A Permian-Triassic Boundary in the Middle East: A Review

The Middle Permian - Early Triassic Khuff Formation occurs throughout the subsurface in the Middle East and is believed to contain the biggest gas reserves in the region. Along the epeiric Arabian platform shallow-water carbonates and evaporites prevail in the northern and central part and pass southward in argillaceous carbonates and siliciclastics. In eastern direction shallow-water carbonates pass in deep marine deposits of the Neo-Tethys. Outcrops in Saudi Arabia, Iran, UAE and Oman provide important analogue data for subsurface geologic models. The Permian-Triassic Boundary (PTB) event, about 251 million years ago, was the time of the most severe mass extinction during the Phanerozoic that heavily affected marine and terrestrial ecosystems. Sedimentary rocks of the Khuff Formation and equivalent formations in the Middle East yield abrupt litho- and biofacies changes which are believed to be the result of events associated with Permian- Triassic Boundary (also called end-Permian mass extinction in the literature) and the Early Triassic recovery interval.