Sanjiaoshan Fm
Type Locality and Naming
The type section is located in the area from Sanjiao Mt. to Da’an River, Shenshu Region, Tieli City, Heilongjiang Province (Huang Benhong, 1977). It was named by the Heilongjiang Regional Geological Survey Party, and Huang Benhong in 1968.
Lithology and Thickness
Claystone and Volcanics. Lower part is composed of grey-black silty and carbonaceous slates, intercalated with a small amount of sandy conglomerate, yielding abundant plant fossils (phytolites), with siltstone at its base, and with a thickness of 880 m. Upper part consists of grey-brown andesitic porphyrite and tuffaceous clastic rocks, with a thickness of 440 m. Total thickness is 1320 m.
Relationships and Distribution
Lower contact
No clear contact relationship with the underlying Tumenling Fm at the type section.
Upper contact
Regional extent
Distributed in the Da’an River and Sanjiao Mt. areas of Shenshu Region.
GeoJSON
Fossils
Plant fossils (phytolites) include Callipteris shenshuensis, Comia shenshuensis, Supaia, Noeggerathiopsis, Compsopteris tchirkovae, Rhipidopsis, Xinganphyllum, Sphenopteris, Ginkgophyllum.
Age
Depositional setting
It is interpreted as lake-facies clastic, volcanic and volcaniclastic rock formations.
Additional Information