Beikuang Fm
Type Locality and Naming
The type section is located at Beikuang W26P102 section and Wunur W26P1 section, 8 km north of Wunur, Heilongjiang Province. It was named by the No 2 Branch Team of Heilongjiang No 2 Party of Regional Geological Survey in 1981.
Lithology and Thickness
Siltstone, chert. The lower part of the formation is mainly composed of dark-gray fine-grained pelitic calcareous metaclastic rocks and silty mudstone intercalated with limestone lenses, and bears mainly coral. The Upper part consists of yellowish-brown, gray and dark-gray chert (with radiolaria), siliceous mudstone and fine-grained clastics, and contains abundant fossils. The thickness is more than 40 m.
At the Beikuang section and in the Forest Farm area of Zhadun River, the formation is dominated by clayey and calcareous siltstone, intercalated with thin-bedded limestone, and the maximum outcropping thickness can reach 150 m.
Relationships and Distribution
Lower contact
At the type section of the Beikuang Fm, the basal slate and siltstone include some breccia, which makes it easily to differentiate from the underlying sparry limestone of the Wunur Fm.
Upper contact
The formation may be partly in a disconformable contact with the overlying Huoboshan Fm conglomerate
Regional extent
GeoJSON
Fossils
The important fossils include conodonts Polygnathus costatus patulus, Icriodus corniferleptus, Polygnathus linguiformis; coral Favosites karpinskyi, Tyrganolites.
Age
Depositional setting
Additional Information