Sedimentary facies in the Middle Triassic Badong Formation in Shizhu, Chongqing

Three types of lithofacies are recognized for the Middle Triassic Badong Formation in Shizhu, Chongqing, including:① purplish red and grayish green mudstone and shale;② brownish yellow, purplish red and grayish brown lithic quartz sandstone, and ③ light grey carbonate rocks. The bedding structures include horizontal bedding, parallel bedding, ripple bedding and tabular cross-bedding. Sedimentary facies types are separated into the barrier coastal facies, tidal-flat and lagoon subfacies and five microfacies, and sedimentary facies sequences are also constructed. The sea-level changes during the deposition of the Badong Formation exercised a major control on the Badongian sediment types in the study area.