Shangdiyag Fm
Type Locality and Naming
The type section lies from Diyag to Gyiseng, northwest of Zanda County, Tibet. It was named by Guo Tieying et al. in 1991.
Synonym: “upper” Diyag Fm (which is the meaning of Shang-Diyag)
Lithology and Thickness
Sandstone and Claystone. Dominated by clastic rocks, with conglomerate at bottom, and characterized by carbonaceous slate and coal streaks. The bottom part is composed of pebbly conglomerate, with a scouring plane over the Xiadiyag Fm (means the “lower” Diyag Fm), which transitions upward into quartz sandstone, claystone-slate intercalated with coal streaks. Thickness >270 m. In the Xiadiyag Fm and Shangdiyag Fm (means the “upper” Diyag Fm) is seen intrusion of plagioclase-amphibolite dikes.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Xiadiyag Fm
Upper contact
Conformable contact with the overlying Gyiseng Fm
Regional extent
Distributed around Mayang of the Higher Himalayan subprovince and along Doima to Lungmuco of the Karakorum subprovince
GeoJSON
Fossils
The carbonaceous slate contains Inarticulata brachiopod Orbiculoides sp., gastropods and plant fragments of
Age
Depositional setting
It is interpreted as continental-littoral swamp deposits
Additional Information