Suonahu Fm
Type Locality and Naming
The holostratotype is the Suonahu East Section (N33°54′00″, E86°43′00″), Shuanghu, Xizang Autonomous Region (Tibet). Named and measured by the Regional Geological Survey Brigade of Tibet in 1986.
Synonyms: The Suonahu Formation is synonymous with the Maerguochaka Gr, the Shuanghu Gr, the Qiaoertianshan Gr, the Dingqing Gr, and the Zongbai Gr.
Lithology and Thickness
The Suonahu Formation consists of red brick-red, earth-red or bright-red mudstone, clayey siltstone, sandstone, coarse sandstone, gravelly sandstone and conglomerate, interbedded with multi-layer gypsum horizons which is available for mining. The thickness ranges from 530-4300 m.
Relationships and Distribution
Lower contact
The Suonahu Formation unconformably overlies the Kangtuo Fm, the Yanshiping Gr or other Mesozoic strata.
Upper contact
The Suonahu Formation is unconformably overlain by the Shipingding Fm (synonymous with Chabaoma Fm in Qinghai province).
Regional extent
Ngari Prefecture and Naqu Prefecture, Tibet Autonomous Region. Haixi Mongolian and Tibetan Autonomous Prefecture, Qinghai Province.
GeoJSON
Fossils
The Suonahu Formation contains fossils of freshwater gastropods (Lymnae, Gyraulus) and bivalves.
Age
Depositional setting
Fluvial-lacustrine deposit facies.
Additional Information