Fengtai Fm
Type Locality and Naming
No type section was assigned when the formation was erected. An auxiliary section, the Fangniushan section, was proposed by Anhui Bureau of Geology and Mineral Recourses (1987) as representative section of the formation. The section lies 3.2 km southeast of the seat of Fengtai County (111°44’ 19”E, 32°40’29”N), and was measured by Anhui Regional Geological Survey Team in in 1979. In this section, the formation is 96.54 m thick. The Fengtai Formation was named by Xu (1958). The name is derived from Fengtai County, Huainan City, northern Anhui Province. Originally the formation was called Lime Conglomerate Bed or Fengtai Conglomerate respectively by Xu (1956, 1958), and was renamed Fengtai Formation by Anhui Bureau of Geology and Mineral Recourses (1987).
Synonym: （凤台组）
Lithology and Thickness
The Fengtai Formation is a clastic sequence. In the auxiliary section, the formation is divided into 3 lithological beds, from bottom up: (1) greyish red thick-bedded, dolomitic conglomerate (45.63 m); (2) greyish yellow and greyish red medium- to thick-bedded (36.04 m); (3) greyish red, medium- to thick-bedded conglomerate, interbedded with thin-bedded conglomerate with a layer of greyish green shale, 20‒25 cm thick, at the top (14.67 m).
Relationships and Distribution
Lower contact
The Fengtai Fm rests disconformably on the Sidingshan Fm of Ediacaran System. The conglomerate at the base of the Fengtai Formation marked the formation’s lower boundary
Upper contact
It is also in disconformable contact with overlying Houjiashan Fm. The greyish green shale of the Fengtai Formation, which differs notably from the grey foliated phosphoric conglomerate, 5 cm thick, at the base of the Houjiashan Formation, marked its top boundary.
Regional extent
The Fengtai Formation is exposed in the Xuzhou-Huaibei Area of North China Region, and restricted to the Bagongshan District of Huainan City and to the Sishilichangshan area of Huoqiu County, Lu’an City. The formation is stable in lithology, and has maximum the thickness in Fengtai County, thinning northward to 10 m at Jiucaishan and southward to 12 m at Fenghuangshan, and then tapering out beyond.
GeoJSON
Fossils
No fossil has been found from the formation
Age
Depositional setting
The formation represents coastal colluviation setting.
Additional Information