Jinjiling Fm
Type Locality and Naming
Liu Lu named the Jinjiling Group in 1964. The named section is located in Jinjiling near Zhangjiachuan in the west of Zhen'an County, Shaanxi. In 1963, Jiang Chunfa et al. identified a set of sandy and calcareous shales with thin limestone strata distributed near Jinjiling as the Lower Triassic based on the fossils. In 1964, Liu Lu first used a name of the Jinjiling Group to describe these strata. While affirming that the Jinjiling Group represents the Early Triassic, he also doubted whether the middle and upper part belonged to the Lower Triassic. In 1966, the 10th regional survey team of Shaanxi Geological Bureau renamed the Jinjiling Formation and determined its age as the Early Triassic.
Synonym:
Lithology and Thickness
Brownish and gray-black sandy shale and calcareous shale interbedded with dark gray thin layer argillaceous strip limestone, with limonite about 10 cm and argillaceous clastic weathering crust as the bottom boundary. The thickness is 113 m in named section. The thickness varies greatly from 44 to 1000 m in Shaanxi Province.
Relationships and Distribution
Lower contact
It is conformable contact with the underlying upper Permian Longdongchuan Fm [Not yet in Permian lexicon; Strat-names book entry says only "limestone" in Zhen'an County]
Upper contact
It is conformable contact with the overlying Middle Triassic Linggou Fm
Regional extent
The formation mainly distributed in Jinjiling, Niejiagou, and Yundoutan West Hills on both sides of Chengjiachuan, Zhenan County, Shaanxi Province.
GeoJSON
Fossils
The fossils are mainly bivalves, as well as ammonoids and brachiopods.
Bivalves: Claraia sp., C. hunanica, C. ex gr. stachei, C. zhenanica, C. Griesbachi, Pseudoclaraia cf. wangi, Eumorphotis multiformis, Gervillia exporrecta
Ammonoids: Ophiceras sp., Lytophiceras cf. chaumunds
Age
Depositional setting
The formation is a shallow marine facies.
Additional Information