Lisangou Fm
Type Locality and Naming
The Lisangou Formation was erected by Hong Youchong et al from the North China Institute of Geology in 1975. The section for the designation is from Lisangou to Yangduiyaozi of the Guyang County of Inner Mongolia (109°50′E; 41°5′36″N).
Lithology and Thickness
Lower part of the Lisangou Formation is represented by break red and gray white conglomerate. Middle part is gray green and gray purple sandy mudstone with sandy conglomerate. Upper part is gray green and gray white sandy conglomerate, sandstone, sandy mudstone with mudstone. It is 531 m thick.
Relationships and Distribution
Lower contact
The base marked by brick-red thick-bedded conglomerate lies unconformably on the Caledonian plagioclase granite. It often lies unconformably on the Pre-Cambrian metamorphosed rocks, the Jurassic or older rock bodies.
Upper contact
The top marked by gray green and gray white sandy conglomerate, sandstone and sandy mudstone lies conformably under the overlying Guyang Fm.
Regional extent
The present formation occurs in the intramontane basin of the Yinshan Mountain, especially developed in the Guyang basin of Inner Mongolia. Its lithology does not vary considerably. In Ulanaobao and Huhegaqia, the lower part of the formation is dominated by gray green and break red conglomerate, granule conglomerate and gravel-bearing grit, while the upper part light gray purple and yellow brown gravel-bearing sandstone. In the Daqingshan area, the lower part of the formation is built up by purple red thick-bedded conglomerate interbedded with arkose with mudstone, sandy shale and coal streaks; while the upper part gray purple conglomerate and arkose with marl. The formation is of lacustrine deposition. It ranges from 100 to 800 m in thickness.
GeoJSON
Fossils
The formation yields bivalves Ferganoconcha cf. subcentralis, F. estheriae formis, Sphaerium anderssoni, S. inflatum; Reptilia Psittacosaurus guyangensis; ostracods Cypridea unicostata, C. trita, Rhinocypris foveata, Lycopterocypris infantilis, L. eggeri, Ziziphocypris linchengensis, Darwinula contracta. It also contains sporopollen grains represented by the Concavissimisporites-Cicatricosisporites assemblage, insects and gastropods. In Gedu-Xigou of Quansheng of west Urad Qianqi it also yields Fish Lycoptera cf. woodwardi, estheria Lianoningestheria sp.
Age
Depositional setting
It is mainly of fluvial deposition.
Additional Information