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Yaodonggou Formation
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Yaodonggou Fm base reconstruction

Yaodonggou Fm

Period: 
Neoproterozoic

Age Interval: 
late Qingbaikouan (late Tonian), Qb (14)


Province: 
Qinghai, Gansu

Type Locality and Naming

Middle Qilian (north-central Gansu-Qinghai border region). The Yaodonggou Fm was named by Qian Jiagi et al. in 1986. The naming section is located at Yaodonggou, Shibaocheng Township, Subei Mongolia Autonomous County, Gansu Province. Uppermost formation in Gongcha Gr.

Synonym: （窑洞沟组）


Lithology and Thickness

This formation consists of gray, dark gray medium- to thick-bedded cryptocrystalline and microcrystalline limestone, oolitic limestone, clotted limestone, brecciated limestone and dolomite interbedded with purple red, dark gray calcareous slate. Abundant stromatolites occur in the limestone and microplants occur in the slate interbeds. It is 457-863 m thick.


Lithology Pattern: 
Reef limestone


Relationships and Distribution

Lower contact

It is conformable onto the underlying Hashihar Fm

Upper contact

The top lies unconformably below the Sinian Baiyanggou Fm in north Qilian, and disconformably below the Shibandun Fm, Duoruonuor Gr of Sinian in middle Qilian.

Regional extent

Middle Qilian (north-central Gansu-Qinghai border region). Extending eastwards to Wugeshan area in Qinghai Province. The formation is well distributed in Dagongcha Yaotonggou, Subei County, middle Qilian and Jingtie Mt. -Daliugou and Guliangxia area in north Qilian.


GeoJSON

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Fossils

Stromatolites are Gymnosolen leuis, G. cf. ramsayi, G. cf. furcatus, G. atttenuata, G. confragosus, Katauia karatauia, K. dalijiaensis, Linella zhuica, L. jinxianensis, L. cf. auis, Jurusania cylindrica, J. asymnetrica etc. Microplants: Asperatopsophosphaera sp., Pseudozonosphaera sp., Polyporata sp. etc.


Age 

late Qingbaikouan (late Tonian)

Age Span: 

    Beginning stage: 
Tonian

    Fraction up in beginning stage: 
0.6

    Beginning date (Ma): 
832.00

    Ending stage: 
Tonian

    Fraction up in the ending stage: 
0.8

    Ending date (Ma):  
776.00

Depositional setting


Depositional pattern:  


Additional Information

Paleolatitude is 6.6°N with a paleomagnetic pole at -12.4°ψ, 170.6° λ,.


Compiler:  

Extracts from The Neoproterozoic Erathem (chapter in Stratigraphic Lexicon of China, draft of 2022) by Gao Linzhi, Ding Xiaozhong, Zhang Chuanheng, Zhang Heng.