Huanglianqiao Fm
Type Locality and Naming
The type section is located at east shore of Fujiang River, Huanglian Bridge, Tongkou Jianshe Township, Jiangyou County, Sichuan Province. It was named by Triassic Formation, Southwest Team, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences in 1977. Lowermost formation in Tianjingshan Gr.
Synonym: Tianjingshan Fm [as used by Tong et al. (2019, Triassic integrated stratigraphy and timescale in China, Science China: Earth Sciences, v. 62, no. 1)]
Lithology and Thickness
It is composed of grayish-yellow, blue-gray thick limestone, containing flint clumps and bands, with black-gray intermediate bioclastic limestone and argillaceous limestone in the middle and upper part. The thickness is 108.6 m.
Relationships and Distribution
Lower contact
The bottom is conformable contact with the top of the underlying Middle Triassic Leikoupo Fm with anhydrite dolomite.
Upper contact
The top is conformable contact with the overlying Ma'antang Fm with black-gray bioclastic limestone.
Regional extent
This formation is distributed in the long and narrow belt along the front line of Jiangyou, Beichuan, Anxian, and Mianzhu in Longmen Mountain, Sichuan Province. It extends about 160 km, and its thickness varies greatly, ranging from 6 to 333 m thick.
GeoJSON
Fossils
Foraminifera: Dentalina sp., Frondicularia sp., Nodosaria spp., Polypommina sp., Ophthalmidium sp., Ammodiscus sp., Glomospira sp., Echinoderms: Isocrimus separatus, Trawmatocrinus hsuei, Cyclocyclicus laevigatus; Bivalves: Plagiostoma cf. beyrichi, Halobia subcomata, H. cf. kui, Gastropods: Scularia triadua.
Age
Depositional setting
It is interpreted as shallow water deposits.
Additional Information
See the Tianjingshan Group.