Tieshikou Fm
Type Locality and Naming
The type section is located at the Tieshikou in Xinfeng Country, Jiangxi. It was named as Tieshikou System by Xu Keqin and Ding Yi in 1943. It is named as Tieshikou System, which represents the Early Triassic strata dominated by clastic rocks in the Xinfeng area of Jiangxi Province. It was rarely cited, and the geological teams in Jiangxi generally called the Daye Fm or Daye Gr (Table Group of Jiangxi Geological Bureau, 1980; Jiangxi Bureau of Geology and Mineral Resources, 1984). It was renamed as Tieshikou Formation by Kong Cunli in 1988, which was equivalent to the lower part of Tieshikou System, belonging to Induan. In 1992, Wang Zunzhou et al. suggested that the limestone in the upper part of this formation distributed in northern Jiangxi should belong to Xiangcheng Gr, and divided this formation as the upper, middle and lower parts that are all dominated by clastic rocks according to the suggestion of Kong Cunli (1988).
Synonym:
Lithology and Thickness
This formation is mainly composed of gray, yellowish-brown siltstone, fine sandstone, mudstone intercalated with a small amount of limestone, which could be divided into three parts.
Lower part belongs to Permian-Triassic transitional beds, which is composed of gray, yellowish-brown silty mudstone, siltstone and fine sandstone with thickness ranging from tens of centimeters to several meters. Middle part consists of gray, grayish-green, yellowish-brown silty mudstone and siltstone intercalated with mudstone, 140 to 570 m thick; Upper part is composed of yellowish-brown, pink, grayish-green siltstone, silty mudstone, intercalated with thick bedded gray limestone and marl, 32 to 180 m thick.
Relationships and Distribution
Lower contact
The Tieshikou Fm is conformable in contact to underlying Changxing Fm or Dalong Fm
Upper contact
It is conformable in contact to overlying brecciated dolomite of the Xiangcheng Fm or limestone of Yuanxi Fm
Regional extent
The formation is widely distributed in Jiangxi, including Xiushui, Wuning, Ruichang, Wanzai, Gao'an, Pingxiang, Yichun, Fanyi, Shangrao, Lianhua, Longnan, Xinfeng and Chongyi counties. The thickness varies greatly from 46 m to 759 m.
GeoJSON
Fossils
It mainly yields bivalves, with conodonts, brachiopods and ostracods at the lower part. The lower part belongs to a brachiopod, bivalve, conodont, and ostracod assemblage: Waagenites barusiensis-Towapteria scythica-Hindeodus parvus-Hollinella tingi assemblage. The middle part could be divided into three bivalves’ assemblage: Claraia wangi assemblage; C. stachei assemblage; C. aurita assemblage. The upper part belongs to Eumorphotis multiformis bivalve assemblage.
Age
Depositional setting
It is interpreted littoral-neritic sea environment
Additional Information