Naolihe Fm
Type Locality and Naming
It was named by the Wusulijiang Geological Party under the Academy of Sciences of China as the “Naolihe Rock Series” in 1957. The naming section is located on the southern bank of the Qi’erxin River, a tributary on the right side of the Naoli River, Raohe County, Heilongjiang Province, with its reference section being situated in the vicinity of the Nanshichang Mt of Raohe County.
Synonym: （挠力河组）
Lithology and Thickness
Representing a set of slightly metamorphosed yellow-green phyllites, slates, grey-white and black siliceous slates and tuffaceous sandstones, with an estimated thickness of over 1000 m, but with a controlled thickness of only 210 m.
Relationships and Distribution
Lower contact
Its basal part is in an unconformable contact with the granites. Regionally, the schematic strat column indicates the next older unit is the Xiangyang Fm (early Jurassic),
Upper contact
Its top part being in a fault contact with the siliceous rocks of unknown age. Regionally, the schematic strat column indicates the next younger unit is the Donganzhen Fm (late Jurassic-early Cret).
Regional extent
The formation is distributed largely in the areas of the Erlianqiao Bridge, Shichang, Wupao and the Dumu River in Raohe County.
GeoJSON
Fossils
It yields Radiolaria fossils as represented by the Stichocapsa convexa-Stichocapsa japonica assemblage, whose key members are Stichocapsa, Tricolocapsa, Eucyrtiellum, Syringocapsa, Mirifasus, Parvicingula and Hsuum.
Age
Depositional setting
The formation belongs to bathyal deposits, and the Radiolaria colony contained in the formation shows its cold-water type and ecological characteristics of medium-height latitude, thus indicating that the then Nadan-Hada terrain had gradually moved from medium-low latitude sea domain to medium-high latitude region.
Additional Information
These strata in respect to the above terrain might serve as chaotic mélange rock mass from a foreign system, and do not represent a fixed stratigraphic position, showing only some deposits and biota of a definite age.