37 Tongyusi Fm
Type Locality and Naming
The type section is located at Harza on the northern slope of Qimantage, Qinghai Province. It was named by No.8 Branch Team of Qinghai Team of Petroleum Reconnaissance Survey in 1958 and was quoted by Qinghai Team of Regional Geological Survey (1965, 1969).
Lithology and Thickness
Volcanics, Sandstone. This formation has mixed lithologies of volcanics interbedded in clastic to carbonate sediments. It is 1316 m in total thickness.
Lower part is composed of grayish-green slate, feldspathic quartz sandstone and grayish-green andesite, grayish-white rhyolite, grayish purple andesitic agglomerate, etc. Middle part is gray thick-bedded pebble-bearing sandy limestone intercalated with siltstone, grayish-purple conglomerate and pebble-bearing sandstone. Upper part consists of gray dacite, fine volcanic breccia, tuff, and silty slate intercalated with light-grayish purple rhyolitic andesite, etc.
Relationships and Distribution
Lower contact
It is in an intrusive contact with the underlying Variscan granite. Regionally, the next older formation is the Qigaisu Gr (also volcanics)
Upper contact
It is in a disconformable contact with the overlying Wulonggou Fm of Lower Carboniferous.
Regional extent
GeoJSON
Fossils
The middle part yields brachiopods Cyrtospirifer sinensis, C. chaoi, Daralenlodon sp., Tenticospirifer sp.
Age
Depositional setting
Additional Information