Majiaoba Fm
Type Locality and Naming
The type section is located at Yuecun Village, Maojiaoba, Jiangyou, Sichuan. It was named by Fan Yingnian in 1978.
Lithology and Thickness
Fe-rich Claystone and Clayey Limestone. Purple-red shale, oolitic hematite (ooid diameters 2−3 mm), gray and yellow moderately thick- to thick-bedded clayey limestone interbeds. The limestone is sometimes of oolitic and nodular textures, and the hematite layer is 1−2 m thick (of commercial value as a small deposit). 12−72 m thick. The oolitic hematite layer is thinning southwestward, with hematite ooids decreasing in number, and replaced mostly by yellow-gray limestone, sandy limestone and bioclastic limestone around Tongkou.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Changtanzi Fm
Upper contact
Disconformable contact with the overlying Zongchanggou Fm
Regional extent
Distributed in Beichuan County at Yawozi and Lijiayuan of Tongkou (the thickest), Yuecun Village of Maojiaoba of Jiangyou, and Heiwuling of Zhangbagou.
GeoJSON
Fossils
The limestone yields Corals Pseudouralinia irregularis, Siphonophyllia minor and Kwangsiphyllum longiseptatum; Brachiopods Eochoristites neipentaiensis, E. beichuanensis, E. chio, Martiniella chinglungensis elongata and Cleothyridina lamellose.
Age
Depositional setting
It is interpreted as neritic deposits.
Additional Information