Gaofengsi Fm
Type Locality and Naming
Chuxiong Basin. The Gaofengsi Formation was erected by the First Regional Geological Survey Team under the Yunnan Bureau of Geology and Mineral Resources in 1965. The type locality for the designation is in Gaofengsi of the Mouping County, Yunnan. The reference section is in Puchanghe of the Pupeng Town of Xiangyun, Yunnan.
The Gaofengsi Formation erected represents the rock bed consisting primarily of gray, gray yellow and gray green sandstone between the Tuodian Fm and the Puchanghe Fm, which was assigned to late Late Jurassic. In 1966 the Yunnan Regional Geological Survey Team measured the section in Puchanghe of Pupeng of the Xiangyun County, Yunnan, which was assigned to Early Cretaceous.
Lithology and Thickness
The Gaofengsi Formation is dominated by gray, gray yellow and gray green thick-bedded quartz sandstone, intercalated with purple red and purple gray mudstone, siltstone, granule conglomerate and grit beds, with conglomerate at the base. It is 702 m thick.
Relationships and Distribution
Lower contact
The base of the formation marked by light gray and gray purple medium-grained sandstone-grit and gravel-bearing sandstone with conglomerate is distinguished from the underlying Tuodian Fm comprising purple red sandy mudstone, thin- to moderately thick-bedded sandstone interbedded with fine sandstone with marl lenses. The formation contacts disconformably with the underlying Tuodian Fm.
Upper contact
The top of the formation is marked by purple red thick-bedded calcareous mudstone with yellow green sandstone and mudstone bands. The formation is in conformable contact with the overlying Puchanghe Fm.
Regional extent
The formation crops out in Xiangyun, Yaoan, Dayao, Tuanshan of Yongren, Mouding and Shuangbai of Chuxiong in central Yunnan. It is persistent in lithology and generally ranges from 200 to 600 m, several thousand meters at maximum. In Yongren, Yongsheng and Pupeng on the margin of the basin it increases in the amount of sandstone and conglomerate and is 260 m, 400 m and 700 m in the three localities respectively. It is mostly 400-700 m thick in Dayao, Yaoan and Chuxiong.
GeoJSON
Fossils
The formation yields bivalves Nakamuranaia chingshanensis and Trigonioides antiques; Ostracods Monosulcocypris reniformis and M. magna; Charophytes Flabellochara grovesi and Nodoclavator puchangheensis; in Dayao and Yongre also yields bivalves Sphaerium cf. wiljuicum, Ostracods Pinnocypridea dayaoensis, Estheria Orthestheria sp.
Age
Depositional setting
The formation is an important cupreous horizon and is of fluvial-lacustrine facies.
Additional Information