The Huangshanjie Formation of Upper Triassic in the southern Junggar Basin is mainly a set of terrigenous clastics, including conglomerates, sandstones, siltstones and mudstones etc. According to the study on field outcrops, a typical braided river delta sediment was recognized. Studies on sedimentary facies, subfacies and microfacies show that the sequence structure and microfacies types developed in the braided revier delta are similar to those in the meandering river delta. Compared with the meandering river delta, the sediments of braided revier delta are coarser in size, and the sediments of the braided distributary channel in the braided delta plain are widely spread, while the sediments of the inter-braided channel are not well developed. The microfacies types of braided river delta front include the subaqueous distributary channel, mouth bar, sheet bar, and subaqueous interdistributary channel. Subaqueous distributary channel was well developed. Based on the detailed study on sedimentary characters of outcrop, the sedimentary model of the braided river delta of the Huangshanjie Formation was set up. The thickly-bedded conglomerates and conglomeratic sandstones developed in braided river delta are widely distributed, and are favorable oil and gas reservoirs.
