Gagyai Fm
Type Locality and Naming
Himalayan South Belt near Kashmir. The Gagyai Formation was erected by Liang Dingyi et al in 1991. The section for the designation is from Bolinxiala-Chagagou of the Zanda County, Xizang (79°25′; 31°20′).
In 1987, the unpublished formation name was used by the Regional Geological Survey Team of the Xizang Bureau of Geology and Mineral Resources (in the 1:1000000 Wangadake-maping Report).
Synonym: Gajie Fm
Lithology and Thickness
Lower part of the Gagyai Formation is represented by gray black, brown black and black clayey siltstone with brown moderately thick-bedded quartz fine sandstone and yellow thin-bedded clayey limestone lenses. Upper part is purple gray moderately thick-bedded fine-grained greywacke, black thin-bedded sandy shale, brown gray clayey sandstone and black clayey siltstone.
Relationships and Distribution
Lower contact
Regionally, the base of present formation, made up of black clayey siltstone, lies conformably on the underlying Jurassic Fangmachang Fm.
Upper contact
Conformable contact of its uppermost purple gray moderately thick-bedded fine-grained graywacke with the basal light gray massive limestone of the overlying Bolinxiala Fm
Regional extent
It occurs in Bolinxiala, Rangmaru and Gagyai of the Zanda County and Fangmachang of Daba of the Zanda County. It is persistent in lithology, with glauconite at the base in some places, and ranges from 100 to 480 m in thickness.
GeoJSON
Fossils
In the Bolin area, it yields ammonites such as Euthymiceras (Octagoniceras) polyacantum, E.(O.) octagonus, Neocomites sp., etc.
Age
Depositional setting
Additional Information