Qianfoya Fm
Type Locality and Naming
It was named by Zhao Yazeng, Huang Jiqing as the Qianfoya Horizon in 1931. The naming section is located at the Qianfo Cliff east of Guangyuan City, Sichuan Province, with the section at Guangyuan City (Wang Si’en, 1958) serving as its reference section.
Synonym: （千佛崖组）
Lithology and Thickness
Lower part is composed mainly of grey sandy shales and sandstones, intercalated with thin layers (or stripes) of shelly limestones. Upper part is yellow and yellow-grey mudstones and shales, intercalated with poststones (= fine-grained sandstone), with a thickness of 265 m.
Relationships and Distribution
Lower contact
Its basal part with a layer of grey conglomerates is in a disconformable contact with the underlying Baitianba Fm
Upper contact
Its top part with a layer of yellow massive medium-grained sandstones (known as the Guankou Sandstone) is in a conformable contact with the overlying Xiashaximiao Fm
Regional extent
The formation is distributed extensively in the Sichuan Basin, with a consistent lithology in various regions, but with a definite variation in its thickness. In the areas of Jiangyou, Wangcang, Wanyuan and Daxian Counties in the northwestern and northern parts of the Sichuan Basin its lithology is similar to that in the Guangyuan region, with a thickness varying in a range commonly from 200 m to 300 m, with the greatest thickness reaching 400-600 m. In the central and western parts of Sichuan Province both the upper and lower parts of the formation are intercalated with purple mudstones, with a greater variation in their thickness, being tens of meters to more than 300 m. As in the areas of Yibin City, Zigong City and Weiyuan County there are found only remains of sandstones and lime-conglomerates from the lower part of the formation (being of 0-37 m in thickness).
GeoJSON
Fossils
It yields such plant fossils as Coniopteris hymenophylloides, Cladophlebis sp. and Ptilophyllum pectin, and bivalve fossils as represented by Lamprotula (Eolamprotula) cremeir and Cuneopsis johannisboehmi. In addition to the above-mentioned fossils, it also yields Ostracods, Spinicaudata and Charophyta fossils.
Age
Depositional setting
Additional Information