Mengyejing Fm
Type Locality and Naming
Simao Basin. The reference section is located at Yelang Mountain of Mengyejing 26 km northwest of the seat of Jiangcheng County, Yunnan. Named by No. 16 Geological Party, Yunnan Bureau of Geology, in 1960.
Lithology and Thickness
The formation is a sequence of saline lake red sandy mudstone with evaporite deposits and one of the important horizons hosting evaporite deposits. The section is divided into 18 beds and the upper, middle and lower members, with a total thickness of 470 m. Beds 1–4 make up the Lower member, 70 m thick; beds 5–16 are the Middle member, 370 m thick; beds 17 and 18 are the Upper member, 30 m thick. The strata are mainly purplish red calcareous-clayey sandstone and mudstone. The upper and lower parts each have a saline horizon and the middle part is mainly freshwater deposits, i.e. there is a rhythm of salinization-freshening-salinization.
Relationships and Distribution
Lower contact
It is disconformable with the underlying Late Cretaceous strata (Mankuanhe Fm)
Upper contact
It has a conformable contact with the overlying Eocene Guolang Fm.
Regional extent
This formation is widespread and varies greatly laterally. Its thickness may reach more than one thousand meters in drilling wells and ~500 m near continental margins.
GeoJSON
Fossils
The formation contains the charophytes Obtusochara-Tectochara-Rhabdochara assemblage and the ostracods Sinocypris-Parailyocypris-Quadracythere assemblage.
Age
Depositional setting
Additional Information