Tianpeng Fm
Type Locality and Naming
The type section of the Tianpeng Formation is the Tianpeng-Bocaitian section (105°25’E, 23°18’N). It is the lower portion of same type section shared by the overlying Longha, Tangjiaba, and Bocaitian formations, lying 9.5 km northwest of the Tianpeng Town, or about 40 km southwest of the seat of Funing County. The long section spans the border between Funing and Malipo counties with the Tianpeng belonging to Funing County on the east and Bocaitian belonging to Malipo County on the west. It was measured by the Guangxi Bureau of Geology and Guangxi Reginald Survey Team in 1965. The Tianpeng Formation was published by Liu Yuanzheng et al. (1965) from Geological Bureau of Guangxi Zhuang Autonomous Region (1965). The name is derived from Tianpeng Town in Tianpeng Township, Funing County, southeastern Yunnan Province, and was originally appeared in a 1964 manuscript by the No. 4 Brigade of Yunnan Regional Geological Survey Team.
Synonym: （田蓬组）
Lithology and Thickness
The Tianpeng Formation is mainly a carbonate sequence alternated with clastic rocks. It is dominated by light grey, greyish green, and greyish black, thin-bedded striped argillaceous limestone and dolomitic limestone, alternated with shale and silty mudstone. There is a layer of dark grey, medium-bedded oolitic limestone, 20 m thick, in the middle part of the formation in the type section. In the type section, the Tianpeng Formation is 1134 m thick.
Relationships and Distribution
Lower contact
The Tianpeng Fm is in conformable contact with the underlying Dazhai Fm. The lower boundary of the formation is defined by disappearance of yellowish green shale of the Dazhai Fm.
Upper contact
The Tianpeng Fm is in conformable contact with the overlying Longha Fm. The upper boundary is defined by appearance of dolomitic limestone at the base of Longha Fm.
Regional extent
Tianpeng Formation is exposed in the southeastern part of the Yangtze Area of South China Region, very close to the Jiangnan Slope Area, distributed in the counties merely in southeastern corner Yunnan Province, including Finning, Guangnan, and Wenshan counties belonging to the Wenshan Zhaun-Miao Autonomous Prefecture, and Menzi and Pingbian counties belonging to the Honghe Hani-Yi Autonomous Prefecture. The formation is rather stable in lithology, whereas the thickness significantly increases northeastward, varying between 214.5 and 1259 m.
GeoJSON
Fossils
In the type section, the middle part of Tianpeng Formation yields trilobites Manchouella sp., Proasaphiscus sp., and “Ptychoparia” sp. and in the upper part the formation yields Bailiella cf. lantenoisi. In other localities, the lower part of formation yields trilobites Kaotaia magna, Kunmingaspis yunnanensis, and Mengzia mengziensis, and the upper part yields Bailiella lantenoisi, Wuania taitzuensis, and Manchouella liaotungensis.
Age
Depositional setting
Additional Information