Jigongshan Fm

The type section is located at Jigongshan area, Puxi County, Hubei Province. It was named by Regional Geological Survey Institute of Hubei Geological Bureau in 1975. The original group refers to the lower coal group of the Wuchang Group. In 1924, Xie Jiarong created the Wuchang coal measure, which is located in the Jurassic period, and the layer is located between the Triassic Puxi Formation and the Jurassic Chengchao Fm quartz sandstone. In 1962, Si Xingjian and Zhou Zhiyan were renamed the Wuchang Group, and the age was set from the Late Triassic Rhaetian to the Early Jurassic Aalenian. Wang Shaowei et al. in 1966 called the Wuchang coal measure, and it was divided into four coal groups, the lower, middle, upper, and top coal groups. According to the sporopollen assemblage, the coal group was designated as the Late Triassic. The middle, upper and top coal formations are Jurassic. In 1975, the Hubei District Research Institute passed the conclusion that the rich plants Drepanozamites nilssoni, Cycadocarpidium erdmanni, etc. were obtained on the 1:200, 000 Pusitou sheet, and combined with the conclusions of sporopollen, the Xiamei Fm was separated and named as the Jigongshan Fm, and its age was determined as late Triassic.

Synonym:

The section mainly consists of yellow-green, brown-yellow siltstone, mudstone intercalated with carbonaceous shale, fine sandstone, containing 1-3 layers of coal and siderite nodules or thin layers of iron ore.

Contains the flora dominated by cycads and Difanidae, which is the Cycadocarpidium- Drepanozamites assemblage.