Jijitaizi Fm
Type Locality and Naming
The type section lies 5 km southwest of Jijitaizi, about 82 km north of Jinta, Gansu. It was named by Guo Jingxin et al. in 1967.
Lithology and Thickness
Lower part consists of neritic carbonate rocks. Upper part is littoral clayey and clastic rocks. Thickness >257.4 m at type section. At the Shibanshan section, which is well exposed, the Lower part is the limestone and marble member, containing fusulinids Fusulina sp., Fusulinella sp., etc.; the Upper part is the slate member, dominated by sandy slate intercalated with siltstone, limestone and calcareous conglomerate; containing bivalve Pterionopecten, etc.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Shibanshan Fm
Upper contact
Unconformably overlapped by the Permian strata at Shibanshan section, which is well exposed. Top at type section is not exposed. But, regionally, the next younger unit (on Lexicon chart) is Ganqun Gr.
Regional extent
Distributed in areas such as Shibanshan, Baijianshan, Yin’aoxia and Jijitaizi of southern Beishan Mt.
GeoJSON
Fossils
At Jijitaizi, the formation yields Fusulinids Pseudostaffella sp., Profusulinella prisca and Fusulinella bocki. At the Shibanshan, upper part contains bivalve Pterionopecten, etc.; and the fusulinids in the formation consist of the Pseudostaffella, Profusulinella and Fusulina-Fusulinella zones in ascending order.
Age
Depositional setting
It is interpreted as neritic carbonate followed by littoral clastics.
Additional Information