Sunwu Fm
Type Locality and Naming
Jiayin Basin. The name section is located at north of the Datun village, Zhanhe River, Xunhe Town, Xunke County, Heilongjiang province. It was named by the Research Team of Heilongjiang Geological Bureau in 1965. The type section is the Donggang Section located at the Xuguang Farm in Nenjiang County. Geographical coordinates of the type section: 48°48′10″N, 125°07′20″E (GPS).
Synonym: It is synonymous with Jinshan Fm.
Lithology and Thickness
It is characterized by the loosely cemented grey, yellowish-brown, and greyish-yellow sandstones and sandy conglomerates intercalated with greyish-green or grey mudstones. The sandstones contain ferruginous nodule partly or are with ferruginous cementation, and the Sunwu type iron deposits occur when iron is enriched. The thickness is 78 m in the type section and varies from 10 m to 635 m in the district.
Relationships and Distribution
Upper contact
The Sunwu Fm is in unconformable contact with the overlying Pliocene Xishan Fm basalt.
Regional extent
The formation is distributed in the Xiaoxing’anling Area, which includes Sunwu County, Jiayin County, Nenjiang County, Huma County and Xunke County. In Sunwu-Jiayin Basin, there is no overlying basalts.
GeoJSON
Fossils
Sporopollen assemblages: ?Pinuspollenites- Juglanspollenit, Betulapollenites- Pinuspollenites, and Betulapollenites- ?Artemisiaepollenites.
Age
Depositional setting
Coarse clastic deposits in fluvio-lacustrine environment.
Additional Information