Xiangyang Fm
Type Locality and Naming
It was named by the Compiler
Jingeng Sha (coordinator) Group for the Regional Stratigraphic Chart of Heilongjiang Province in 1979. The naming section is located in the D-IV profile at the southern quarry of Raohe County, Heilongjiang Province, with its reference section being situated in the Northern Hills of Daba, Hongqiling Farm, Raohe County.
Synonym: （向阳组）
Lithology and Thickness
It represents a set of variegated thin-bedded silicolites (= chert?), siliceous shales and yellow-green mudstones, with a controlled thickness of only 160 m.
Relationships and Distribution
Lower contact
Its basal part is also in a fault contact but with the middle Triassic Shichang Fm (not in Triassic Lexicon). Regionally, the next older unit is the Zhenjiang Fm of Late Triassic.
Upper contact
Its top part in type area is in a fault contact with the upper Triassic Zhenjiang Fm. Regionally, the schematic strat column indicates the next younger unit is the Naolihe Fm of Middle Jurassic.
Regional extent
The exact shape of its distribution is unknown except for the controlled sections. It might belong to a large-scale massif within a mélange on the terrene. So some people should think that it is inadvisable to establish a formation for an exotic block (Shao Ji’an and others, 1990).
GeoJSON
Fossils
It yields a Radiolaria assemblage zone as represented by Parahsuum simplum, whose diagnostic members comprise Parahsuum, Hsuum, Canutus, Canoptum, Paracingula and Pseudohsuum.
Age
Depositional setting
The formation belongs to deep-sea deposits.
Additional Information
Age:
Schematic strat column indicates Early Jurassic (Hettangian through Toarcian)
Age span:
Beginning stage: Hettangian
Fraction up in beginning stage: 0.0
Beginning date (Ma):
Ending stage: Toarcian
Fraction up in ending stage: 1.0
Ending date (Ma):
Depositional setting:
The formation belongs to deep-sea deposits.
Depositional-pattern:
Additional Information
Compiler
Jingeng Sha (coordinator)