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Huaniushan Gr

Huaniushan Gr

Period: 
Ordovician

Age Interval: 
late-Middle to mid-Late Ordovician, (13, 14)


Province: 
Gansu

Type Locality and Naming

The type section is at Changliushui, 23 km away from Wufeng Hill in Subei County (95°36′E, 41°13′N), Gansu. In the type area, the Huaniushan Gr recorded an incomplete thickness of 690 m. The Huaniushan Gr was named by No.1 Gansu Party of Regional Geological Survey in 1966, and was published by Gansu Compiling Group for Regional Stratigraphic Scale (1980). Coeval with the upward succession of the Luoyachushan Fm and Xilinkebo Fm.

Synonym: (花牛山群)


Lithology and Thickness

The Group dominated by argillaceous slate and quartzite intercalated with limestone, fine-grained sandstone and conglomerate.


Lithology Pattern: 
Sandy claystone


Relationships and Distribution

Lower contact

Upper contact

Regional extent


GeoJSON

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Fossils

The limestone intercalation in the middle part yields cephalopod Discoceras sp., brachiopod Zygospira sp., Tritoechia sp., gastropod Maclurites sp., Tropidodiscus sp., Donaldiella sp. and bryozoan. In western Huaniushan ore district, a fauna including coral Lichenaria, brachiopod Rostricellula sp., trilobite Encrinuroidae and Pliomicrina sp., gastropod Lophospira sp., Trochonema sp. and Helicotoma sp. is found from 1194 m thick strata. The precise age of this group, however, has not been confirmed based on the found fauna.


Age 

Middle-Later Ordovician. The Huaniushan Gr was previously thought to be Middle Ordovician in age. Gansu Compiling Group for Regional Stratigraphic Scale (1980) suggested a Middle-Late Ordovician age for it. Chen Zhefu and Liang Yunhai (1983) included the Huaniushan Gr in the Lower-Middle Ordovician. Gansu Bureau of Geology and Mineral Resources (1989) defined the Huaniushan Gr to be Middle Ordovician in age.

Age Span: 

    Beginning stage: 
Darriwilian

    Fraction up in beginning stage: 
0.08

    Beginning date (Ma): 
468.52

    Ending stage: 
Katian

    Fraction up in the ending stage: 
0.6

    Ending date (Ma):  
448.23

Depositional setting


Depositional pattern:  


Additional Information


Compiler:  

Jianpo Wang and Xiaofeng Wang