Jiucaiyuan Fm

Tang Zukui et al. named Jiucaiyuan Formation in 1957. The reference section is located at the southern wing of Dalong anticline, 8 km south of Santai Town, Jimsar County, Xinjiang. From 1928 to 1932, Yuan Fuli defined the red rock series of Dalongkou section as the Donghongshan Fm of the Lower Triassic. Donghongshan Formation in the middle of the stratum was classified as the lower Triassic, called the Jiucaiyuan Fm by Tang Zukui in 1957. Jiucaiyuan Formation and the overlying Donghongshan Fm were called the Jiucaiyuan Formation by Xie Hong et al. in 1958. In 1960, Yang Shizhong et al. set up it as a group and defined its age as the Early and Middle Triassic. Now it is the lower formation of the Shangcangfanggou Gr.

Synonym:

It is purple mudstone, gray-green lithic sandstone and siltstone interbedded with unequal thickness. Lower part is mainly composed of gray-green sandstone and siltstone with silty mudstone. In the Middle and Upper part, purplish red mudstone and silty mudstone are mainly interbedded with gray-green fine sandstone. However, there is obvious scour phenomenon on the top of the Jiucaiyuan Formation in Dalongkou. The maximum thickness of Dalongkou section is 220.6 m.

It is rich in vertebrate fossils, as well as ostracod, plants, micro-sporogenesis, megaspore and conchostracan.

Vertebrates: Lystrosaurus hedini, L. weidereichi, Chasmatosaurus yuani, Procacertoides jimusarensis, Santaisaurus yuani. Ostracods: Darwinula rotundata, D. triassiana, D. spp. Plants: Pecopteris sp. Microspores: Limatulasporites—Lundbladispora—Taeniaesporites—Tsugaepollenites assemblage. Megaspores: Pusulosporites inflatus—Trileites assemblage. Conchostracans: Falsisca—Cyclotunguzites assemblage

It belongs to lake swamp facies deposition.