Gerong Fm
Type Locality and Naming
The type section is located at the Cow Farm of Zongza in Batang County, westernmost Sichuan Province near border with Tibet. It was named by Sichuan No 3 Team of Regional Geological Survey in 1977 and was published by Sichuan Compiling Group for Regional Stratigraphical Scale in 1978.
Lithology and Thickness
Dolomite. It is a set of carbonate rock and is mainly composed of light-gray to grayish-white thick-bedded dolomite and dolomitic limestone, partly intercalated with thin- to medium-bedded quartz sandstone. It is 124 m in thickness.
Relationships and Distribution
Lower contact
Conformably on the grayish-white medium-bedded crystalline limestone of the Yiongren Fm of the Upper Silurian.
Upper contact
Conformably overlain by the quartz sandstone at base of the Qiongcuo Fm.
Regional extent
The formation is distributed at Zongza of Batang County and in Dêrong County. Trending to Secang of Zhongdian (now Shangri-La) County, Yunnan Province, the facies changes into interbeds of gray sandy slate with dark-gray thick-bedded limestone, which contain abundant brachiopods and corals fossils.
GeoJSON
Fossils
It yields corals Tryplasma, Lyrielasma, Favosites.
Age
Depositional setting
It is interpreted as a lagoon facies deposit.
Additional Information