Gonganzhai Fm
Type Locality and Naming
SE Hubei. The name of Gonganzhai Formation was given by the Petroleum Department of Jianghan Oilfield in 1962. The type locality is in Gonganzhai of Luodian, Jiangshan County. The type section is the Shimiao section in the Jiangshan County (ca. 113º, 31º).
Lithology and Thickness
The Gonganzhai Formation is composed of brownish red thin-bedded fine- to coarse-grained sandstone, siltstone and muddy siltstone, with intercalations of reddish brown and grayish green sandy mudstone and gypsum layers. The strata are in cyclic bedding. Some basalt beds occur in its base. This formation is 1800~2237 m thick in the Suizhou and Jingshan area, and 200~3353 m in eastern Hubei Province.
Relationships and Distribution
Lower contact
The Gonganzhai Formation is generally unconformably overlies the Dasi Fm or pre-Cretaceous strata angular unconformably.
Upper contact
Its top is covered by Quaternary.
Regional extent
It occurs in the south side of the Tongbai - Dabie mountains, and is well developed in the Jingshan, Yingcheng, Yangxin, Tongshan and Anlu areas.
GeoJSON
Fossils
This formation yields ostracod, charophyte, conchostracan, dinosaur and turtle fossils. They are dominated by ostracods Talicypridea-Cypridea-Candona Assemblage; charophyte Porochara anluensis- P. gonganzhaiensis Assemblage; dinosaur eggs Dendroolithus wangdianensis; and turtle Anhuichelys xinzhouensis. They are Late Cretaceous in age, except turtle of Paleocene.
Age
Depositional setting
Additional Information