Kaishantun Fm
Type Locality and Naming
The type section is located to the west of the Railway Station of the Kaishantun Village, and the reference section is situated in the Mijiang River area of Hunchu City.It was named by the 2nd Regional Geological Survey Party under the Geological Bureau of Jilin Province and together with Yang Qilun and Li Xikun in 1963, and was cited officially by the Compiling Group on the Regional Stratigraphic Chart of Jilin Province (1978).
Lithology and Thickness
Conglomerate and Claystone. It is divisible into two parts. Lower part being composed of grey-green tuffaceous sandy conglomerate, intercalated with grey-black slate. The basal part of the formation consisting of grey-green tuffaceous conglomerate. Upper part consisting interbeds of grey-yellow tuffaceous sandy conglomerate, sandy slate and together with grey-black carbonaceous clayey slate. Many of the carbonaceous slate layers yield plant fossils (phytolites). The thickness is 351-2419 m.
Relationships and Distribution
Lower contact
Disconformable contact with the underlying Kedao Fm, or lateral transition to the partly coeval Qinggouzi Fm.
Upper contact
Disconformably overlapped by the Dalazi Fm of the Lower Cretaceous Series.
Regional extent
Distributed in the area of the Kaishantun Village of Longjing County (with a thickness of 350 m), Dabeigou and Taoyuan areas of Wangqing County, Mijiang area of Hunchun City (with a thickness of 2288 m) and in Chunhua area as well.
GeoJSON
Fossils
The plant fossils (phytolites) comprise the Taeniopteris, Sphenophyllum sino-coreanum, Lobatannularia heianensis, Gigantopteris yabei, Cladophlebis, Pecopteris, Paracalamites, etc. In the Mijiang area of Hunchun City except for plant fossils (phytolites), there are found also bivalves such as Limipecten and brachiopods as represented by Schellwienella sp.
Age
Depositional setting
It is interpreted as dominated by continental molasse, in parts of areas it is intercalated with volcaniclastic rocks.
Additional Information