Sedimentary facies and palaeogeography of the Triassic sedimentary basins in the Bayan Har mountainous area:an example from the Aba-Zoige Basin,Sichuan

The Triassic sedimentary basins in the Bayan Har mountainous area with a total area of about 370,000 km² sandwiched between the Qinling-Qilian-Kunlun and Karakorurn microplates are bounded by the deep faults on the southern margin of the Kunlun uplift on the north,he Longmenshan-Jinpingshan deep faults on the southeast,Garze-Litang deep faults on the southwest, including Hoh Xil, Aba-Zoige, Xiaojin-Barkam, Yajiang and Jiulong basins. In the present paper,the emphasis will be on the Aba-Zoige Basin. Since the outcrops are scarce,much of the basin is now covered by the Quaternary marshes, and composed of the Lower Triassic Bocigou Formation,Middle Triassic Zagunao Formation and Upper Triassic Zhuwo and Xinduqiao Formations.