Minhe Fm
Type Locality and Naming
Xining-Lanzhou-Minhe Basin. The Minhe Formation was erected by the Qinghai Petroleum Prospecting Team in 1973. The section for the designation is in Xiheyan of Xiangtang of the Minhe County, Qinghai.
Synonym: Minhe Gr
Lithology and Thickness
The Minhe Formation is represented by brownish red, light brown and greenish gray interbedded conglomerate, sandstone, clayey siltstone, silty mudstone and mudstone with gypsum. The Minhe Formation is 96 m thick.
Relationships and Distribution
Lower contact
The base of the formation marked by brown massive quartz conglomerate lies unconformably on the underlying Hekou Gr (Huazhuang Fm).
Upper contact
The top marked by brown mudstone with gray green fine sandstone lies unconformably under the Paleogene Xining Gr.
Regional extent
The present formation occurs in the Zhongba-Shipogou area of Ledu of the Minhe basin and on both banks of the Datong river, and is also exposed sporadically in the southern part of Pinganyi, Daxia, Xiaoxia and Shuangshuwan of the Xining basin. On the margins of the basins, the formation is relatively coarse in lithology and is dominated by conglomerate and sandy conglomerate. It is relatively thin in thickness, only 38 m in Shipogou. Towards the center of the basins, it becomes finer in grain size and increases in thickness, generally ranging from 100 to 300 m.
GeoJSON
Fossils
The formation yields ostracods represented by the Talicypridea-Cypridea- Candona assemblage and also includes some important elements such as Talicypridea amoena, Candoniella hubeiensis, Cyprois subglobra; Charophytes Gyrogona, Peckichara, Charites, Latochara, Grambastichara, etc.; and sporopollen grains represented by the Schizaeoisporites- Tricolpopollenites-Classopollis assemblage.
Age
Depositional setting
It is marked by fluvial-lake shore deposition.
Additional Information