Yinchuan Fm
Type Locality and Naming
The type section is at Yushuqinggou 23 km of new region of the Yinchuan City, Ningxia. The Yinchuan Fm was named by Zheng Zhaochang and Li Yuzhen in 1985, and was published by Huo Fuchen et al. (1989).
Synonym: (银川组）
Lithology and Thickness
The Yinchuan Fm is characterized by a deep-water flysch-like sequence of grayish green sandstone and slate intercalated with impure clastic limestone, with a several tens centimeters thick conglomerate at the base. In the type area, the Yinchuan Fm recorded an incomplete thickness of 1589.2 m.
Relationships and Distribution
Lower contact
Upper contact
It is cut by fault in the upper part in the type section.
Regional extent
The Yinchuan Fm has a persistent lithology, and is 1589-1787 m thick. It is mainly seen at Bayinqugetu in Alxa Zuoqi of Inner Mongolia and Helan Mountain segment along the Yinchuan-Bayan Hot Highways in Ningxia.
GeoJSON
Fossils
The strata of the Yinchuan Fm at Daluoshan, Xiaoluoshan and Meishan in Tongxin County, Ningxia had previously been referred to as the Luoshan Fm (Ganxu Party of Regional Geological Survey, 1965), from which graptolites Pseudazygograptus sp., Climacograptus eximius have been found. In Changliushui, Inner Mongolia, graptolites D. (Diplacanthograptus) bicornis, C. (D.) diplacanthus and C. putillus also have been found from the Yinchuan Fm (Inner Mongolia Bureau of Geology and Mineral Resources, 1991). The top yields conodonts Protopanderodus insculptus, Periodon sp. and Oistodus sp.
Age
Depositional setting
Deep-water flysch-like sequence
Additional Information