Triassic sedimentary basins and paleontological features on the Qinghai-Xizang Plateau

The Triassic strata on the Qinghai-Xizang Plateau are conspicuous by their widespread occurrence, various types and abundant mineral resources. These sedimentary strata are considered to be assigned to the intracontinental rift basin deposits that differ from the oceanic basin deposits. The sedimentary basins on the Plateau have gone through two stages of evolution:early and late Indosinian, and may be grouped into three types:Xizang-type, Bayan Har-type and West Qinling-type according to the evolutionary patterns of the basins and paleontological features. Biopalaeogeographically the studied areas should be assigned to the Xizang-West Yunnan, Bayan Har and West Qinling ecological provinces.