Wanglongtan Fm
Type Locality and Naming
Regional Survey Team of Hubei Geological Bureau named in 1973. The named section is located in Wanglongtan, Nanzhang County, Hubei Province.
Synonym: Wanglongtan Formation refers to the Zhongmei Fm of the Mengxianmin Xiangxi Coal Measures in 1929. Regional Geological Survey Team of Hubei (1973) divided the “Xiangxi Coal Measures” in Jingdang area of western Hubei Province into the Upper Triassic Jiuligang Fm, Wanglongtan Fm and Lower Jurassic Tongzhuyuan Fm from bottom to top.
Lithology and Thickness
Mainly yellow brown, green gray quartz sandstone, feldspar quartz sandstone, siltstone, carbonaceous shale and fine sandstone, sometimes with unstable sandstone conglomerate, coal bearing 2 to 5 layers and siderite layers, large wedge shaped bedding is often found in sandstones. Thickness is 603.8 m.
Relationships and Distribution
Lower contact
The occurrence of thick yellow brown quartzite sandstones and sporadic coal bearing lines at the bottom, which is conformable contact with the underlying Jiuligang Fm with gray green feldspar sandstones.
Upper contact
It is in conformable contact with the yellow brown and light gray quartz sandstones of overlying Lower Jurassic Tongzhuyuan Fm
Regional extent
The distribution of this formation is limited and its lithology is relatively stable. The gravel bearing sandstone or conglomerate is mainly found in the Jingmen area. The bottom of North Nanzhang Mujiachong area is the 0.5 – 1 m thick unstable conglomerate. The thickness shows the trend of thick in north and thin in south. The thickness of Wanglongtan and Maopinghe is 781 – 800 m in the north, and is 419 m thick at Xiaozhanghe, Xiaoping and Maoping rivers are 664 – 760 m in the southwest, and Hengxing and Tudiling in Dangyang County are only 160 – 280 m in the south, but 600 – 1000 m in the southeast of Jingmen. Coeval with upper Shazhenxi Fm in nearby region.
GeoJSON
Fossils
Plants: Bernoullia sp., Dictyophyllum cf. nathorsti, Ciroathteris sp., Thaumatopteris browniana, etc.; Bivalves: Utschamiella longa, Trigonodus keperinus, Bakevelloides subhekiensis, Waagenoperna mytiloides, Thracia prisca, etc. and conchostracans, fish.
Age
Depositional setting
Additional Information