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Cenozoic
Cretaceous
Jurassic
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Dongka Formation

Dongka Fm


Period: 
Silurian

Age Interval: 
Llandovery (S1), (33)


Province: 
Xizang (Tibet)

Type Locality and Naming

It was proposed by Liang Shousheng and Xia Jinbao in 1978. The type section is located at about 6 km northeast of Dongqiao Co Lake, approximately 40km southwest of Dongqiao, Bangoin County, Xizang.

Synonym: (东卡组)


Lithology and Thickness

The formation, 442 m in thickness, consists of interbeds of dark grey crystalline limestone with light grey dolomitic crystalline limestone.


Lithology Pattern: 
Limestone


Relationships and Distribution

Lower contact

The underlying formation is still unknown.

Upper contact

It is in conformable contact with the overlying yet-unnamed formation, which is probably belonging to Wenlock or even higher.

Regional extent

t is exposed only in the type section area.


GeoJSON

null

Fossils

The fossils, such as the corals Palaeofavosites felix, P. cf. surikuensis, P. cf. legibilis, Catenipora aff. gothlandicus, Solenihalysites norvegicus, Propora aff. conferta; and the cephalopods Harrisonoceras cf. revesi, Allanoceras xizangensis, ?Edenoceras sp. are abundant in the limestone.


Age 


Age Span: 

    Beginning stage: 
Rhuddanian

    Fraction up in beginning stage: 
0.0

    Beginning date (Ma): 
443.07

    Ending stage: 
Sheinwoodian

    Fraction up in the ending stage: 
0.0

    Ending date (Ma):  
432.93

Depositional setting


Depositional pattern:  


Additional Information


Compiler:  

Wang Chuanshang and Wang Xiaofeng