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Yaxicuo Formation

Yaxicuo Fm

Period: 
Paleogene

Age Interval: 
Middle Eocene to Middle Oligocene , (8d)


Province: 
Qinghai

Type Locality and Naming

Guo Gengcheng named a sequence of carbonate-dominated lacustrine deposits the Yaxicuo Formation in 1989. Its age is Oligocene. In 1994 the Qinghai Bureau of Geology and Mineral Resources renamed it the Yaxicuo Formation and assigned its age to Eocene–Oligocene. The naming section is located at Aburi’ajiazai, Golmud City, Qinghai.


Lithology and Thickness

Lithologically grayish white, thin- to medium-bedded, dolomitic limestone and bioclastic limestone with purplish red sandstone and lime mudstone. The thickness is 230–980 m.


Lithology Pattern: 
Dolomitic limestone


Relationships and Distribution

Lower contact

Its boundary with the underlying Paleogene Tuotuohe Fm is marked by the appearance of limestone.

Upper contact

Its boundary with the overlying Wudaoliang Fm is marked by the appearance of gypsum.

Regional extent

The formation is mainly distributed in the Tuotuo River, Qumar River and Hoh Xil.


GeoJSON

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Fossils

The formation contains the ostracods Eucypris and Candoniella, the gastropods Valvata and the charophytes Obtusochara.


Age 


Age Span: 

    Beginning stage: 
Lutetian

    Fraction up in beginning stage: 
0.0

    Beginning date (Ma): 
48.07

    Ending stage: 
Rupelian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
27.29

Depositional setting


Depositional pattern:  


Additional Information


Compiler:  

Tao Deng, Yuanqing Wang, Qian Li, et al.