Baguamiao Fm
Type Locality and Naming
No type section has been measured or assigned for the formation. Ma (1998) proposed an auxiliary section, the Wapuzi‒Songshuliang section for the representative section of the formation, which was measured by the Shaanxi Regional Geological Survey Team in 1975. The section lies 1 km south of Jijiaping (Songshu) Village (108°32’53” E, 32°11’36” N), Baojiuguang Township (now Bantao Township), Ziyang County, Shaanxi. The Baguamiao Formation was first published by Lu (1962). The name is derived from Baguamiao Temple, 14 km north of Banjiuguan Pass, Ziyang County, southern Shaanxi Province. The name was originally appeared in a 1958 manuscript by the Qinling Regional Geological Survey Team of Shaanxi Bureau of Geology.
Synonym: (八卦庙组)
Lithology and Thickness
The Baguamiao Formation is a carbonate sequence, and in the auxiliary section, it is divided into four lithologic beds, from bottom up: 1, bluish grey, thick bedded breccia (1.8 m thick); 2, thin-bedded, greyish white sandy limestone (26.30 m); 3, bluish grey, thin-bedded micritic limestone, alternated with thin-bedded striped argillaceous limestone (43.80 m); 4, bluish grey, thin-bedded limestone with seams of bone coal (81.30 m). The formation decreases argillaceous content eastward and seams of bone coal southward. In this type section, the Baguamiao Formation is 153.3 m thick.
Relationships and Distribution
Lower contact
The Baguamiao Fm rests conformably on the underlying Maobaguan Fm
Upper contact
It is conformably overlain by the Heishuihe Fm
Regional extent
The Baguamiao Formation is exposed in the Jiangbei Slope Area of South China Region, distributed mainly in southern Shaanxi Province (Bamiao of Zhenba County; Baihekou, Xuetangba, Baiguoping, and Baguamiao of Ziyang County; Jiuchang and Shentian of Langao County; Jinjihe and Jiangxijie of Pingli County; Ciqigou, Daxiongxi, and Huangtuya of Zhenping County) and in northeastern Sichuan (Miaoziba of Wanyuan County) and northeastern Sichuan (Gaoqiaogou, Ppujiaba, Miaoziba of Wanyuan County). At Foyebian, Pingli, and Ziyang, southern Shaanxi, the formation has its maximum thickness of 250 m. Extending eastward and westward, with the minimum thickness, about 100 m thick, in the west part.
GeoJSON
Fossils
No fossil was reported from the Wapuzi‒Songshuliang section. However, in the near Miaoziba-Gaoqiaogou section, 40 km northeast of Wanyuan, northeastern Sichuan Province, diverse trilobite assemblage is reported from this formation with both gnostoid and polymerid trilobites, including Ptychagnostus, Linguagnostus, Clavagnostus, Diplagnostus, Lejopyge, Hypagnostus, Peronopsis, Lisogoragnostus, Aojia, Baojingia [=Eoshenia and Xichuania sensu Yang et al., 1991], Paranomocarella, and Pianaspis (Yang et al., 1991).
Age
Depositional setting
It represents deposits of slope facies.
Additional Information