Dean Fm
Type Locality and Naming
The type section is located at the south bank of Xigulanhe River, about 10 km northwest of No. 727 Forest Farm in Heihe City, Heilongjiang Province. The reference section is at the east side of Jinshuihe River, about 1.5 km east of Jinshui, Handaqi Township in Heihe City, Heilongjiang Province. It was named by Helongjiang No.1 Team of Regional Geological Survey at the end of the 1970s, and Xue Chunding et al. formally quoted it in 1980.
Synonym: De'an Fm
Lithology and Thickness
Siltstone. It is composed of grayish-black to dark-gray siltstone, chlorite slate, tuffaceous siltstone, intercalated with grayish-black or grayish-black crystalline limestone.
It is 540 m thick.
Relationships and Distribution
Lower contact
The formation lies conformably above the Huolongmen Fm of the Lower Devonian.
Upper contact
The formation is conformably below the Genlihe Fm of the Middle Devonian.
Regional extent
This formation is distributed in Nenjiang County, Heihe City, and the northwest area of Xiaoxing’anling of Huma County, Heilongjiang Province.
GeoJSON
Fossils
It contains abundant brachiopods, mainly representing by Borealispirifer orientalis, and a few cephalopods “Devonobactrites” jinshuiensis and corals. Commonly it yields abundant bryozoan fossils of Fenestellae which often appear to be stratified and can be taken as a marker.
Age
Depositional setting
Additional Information