Qiqusi Fm
Type Locality and Naming
Sichuan Basin – central. The Qiqusi Formation was erected by Sichuan Airborne Survey Team in 1980. The section for the designation is in Qiqusi of the Zitong County of Sichuan.
Lithology and Thickness
The Qiqusi Formation is dominated by brick-red mudstone with siltstone and sandstone. The formation is 617.4 m thick.
Relationships and Distribution
Lower contact
Its base marked by the “Zitong sandstone” and the “Niuchang sandstone” lies conformably on the underlying Bailong Fm.
Upper contact
Its top is not observed in the type area; bur regionally it overlain disconformably by the Gudian Fm.
Regional extent
The formation occurs in the northern part of the Sichuan basin. It is persistent in lithology and is thick in the northeastern part and thin in the southwestern part, 440-470 m in Qiqusi of Zitong-Jiange, 220 m in Changxi, 100 m in Bazhong, 10 m in Xiaoxiba of Jiangyou, and 170-260 m in Santai and Zhongjiang.
GeoJSON
Fossils
The formation yields ostracods Pinnocypridea sichuanensis, Jingguella ovata, J. elliptica, Rhinocypris spinosa, Cypridea sp., Minheella minheensis; in Bailongchang of Jiange Jingguella elongata, Pinnocypridea reticulata, P. haishiwanensis, Cypridea sichuanensis, Deyangia reniformis; in Gudian of Zhongjiang ostracods Jingguella acutura, J. arca, J. ovesa, Cypridea angusticaudata major, C. declivis, C. subtriangula, Ziziphocyris sichuanensis, Charophytes Nodosoclavator puchangheensis.
Age
Depositional setting
It belongs to fluvial deposition.
Additional Information