Qipan Fm
(28), lower to middle Kungurian Stage (late Cisuralian Epoch; late-Early Permian)
Type Locality and Naming
The type section is located in the area of the Qipan River about 27 km to the southwest of the Yecheng County, Xinjiang. It was named by the Compiling Group for the Regional Stratigraphic Chart of Xinjiang Uygur Autonomous Region in 1981.
Lithology and Thickness
Clastics and Limestone. It is divisible into five lithological members: First member is composed of the delta-facies sandstone and siltstone, intercalated with limestone. The Second member represents in equipachous interbeds of delta-facies and shallow-sea shelf sandy siltstone and bioclastic limestone. Third member represents interbeds of shallow-sea shelf bioclastic limestone siltstone and siltstone, with its lower part being characterized by the development of biologic-beach facies composed of crinoid stems and oncolites, and with its upper part being characterized by the development of biologic-reef facies composed of sponge, bryozoan and so on. Fourth member represents prodelta-facies sandstone and siltstone, intercalated with limestone, with its middle part being intercalated with subaqueous extrusive basalt. Fifth member is composed of purple siltstone and siltstone, representing delta subaerial plain deposits. The formation is 1476-m thick (?) in the Qipan River section.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Keziliqiman Fm
Upper contact
Conformable contact with the overlying Daliyuer Fm
Regional extent
Distributed in the area to the west of the Pishan River, in the NW-direction the siltstone is increasing in amount gradually, with its thickness reaching as many as 888 m; further east, the sandstone is increasing in amount, but with the thickness of the formation getting smaller to reach 334 m in the Momoke area.
GeoJSON
Fossils
It yields mainly brachiopods and bryozoan fossils, as well as abundant trace fossils. Among the Brachiopod fossils there occur the Richthofenia sinensis, Beecheria sublaevis, Cancrinella pseudotruncata, Liraplecta aspera, Notothyris mongoliensis, Pseudoavonia lopingensis; in addition, there occur also Conodonts represented by Lonchodina festiva, Sweetognathus whitei, Neostreptognothus paquopensis, etc.
Age
Depositional setting
It is interpreted as a succession from delta facies to biologic reef facies to subaerial delta plain.
Additional Information