Shaiwusu Fm
Type Locality and Naming
It was proposed by the 2nd Team of Liaoning Party of Regional Geological Survey ( the present 2nd Team of Inner Mongolia Party of Regional Geological Survey) in 1968 and published in Regional Stratigraphical Scale of Northeast China, Liaoning Province Fascicle, 1978. The type section is located at Xiashihuiyao, Jiefangyingzixiang Township, Ongniud Banner, Nei Mongol Zizhiqu.
Synonym: (晒乌苏组)
Lithology and Thickness
It is characterized by gray medium-thin-bedded to medium-thick-bedded crystalline limestone intercalated with argillaceous limestone, sandstone, slate and schistose calcareous slate.
Relationships and Distribution
Lower contact
Both the lower and upper boundaries are unclear because of magma intrusion. On regional stratigraphic column, the next older unit is the schist of the Shuiquangou Fm of early Silurian.
Upper contact
Both the lower and upper boundaries are unclear because of magma intrusion. In this region, the schematic stratigraphic columns suggest the next younger regional unit is the early Carboniferous volcanics of the Chaotugou Fm.
Regional extent
The formation is widely distributed south of Xar Moron River, Zhaowuda League (Prefecture); the proportion of carbonate rock and clastics varies considerably in lithology. The thickness is from 660-800 m.
GeoJSON
Fossils
It bears corals Catenipora, Halysites, Streptelasma, Syringopora, Thamnopora, Dinophyllum, Palaeophyllum, Mucophyllum; and brachiopod Rhynchospirifer? in the limestone. In the marl, it yields brachiopod Acanthospirifer zaowudaensis.
Age
Depositional setting
Additional Information