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Houlaomiao Gr

Houlaomiao Gr


Period: 
Triassic

Age Interval: 
Late Triassic, (west of TJ52)


Province: 
Gansu

Type Locality and Naming

The type section is located at the named section is located in Houlaomiao, Tianshui County, Gansu Province (ca. 34.5N, 105.7E). It was named by Xu Fuxiang et al. in 1972 and first public cited by the Gansu Province Stratigraphic Table Writing Group in 1980.

Synonym:


Lithology and Thickness

It is yellow-green and gray-green mainly sandstone, mudstone, gravel-bearing sandstone, and conglomerate interbedded with coal interbedded lines, thick in the bottom and fine in the top. The thickness is 256 m.


Lithology Pattern: 
Sandstone


Relationships and Distribution

Lower contact

The lower boundary is covered with yellow-green, gray-green, and purple conglomerate, which is unconformable contact with the older strata. In region TJ52, the next older unit is the Early Triassic sandy limestone of the Renjiawan Fm.

Upper contact

The upper part is false conformable contact with the overlying Jurassic. In region TJ52, this is the Mianxian Gr.

Regional extent

Southeasternmost Gansu. The formation is only seen in Tianshui-Taian area.


GeoJSON

null

Fossils

Plant: Danaeopsis fecunda, Cladophletns zaofiavensis, C. sp., Pterophyllum paacostatum.


Age 

No information given; except "Late Triassic".

Age Span: 

    Beginning stage: 
Carnian

    Fraction up in beginning stage: 
0.0

    Beginning date (Ma): 
237.00

    Ending stage: 
Rhaetian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
201.36

Depositional setting

It is interpreted as lacustrine deposits.


Depositional pattern:  


Additional Information


Compiler:  

Yang Jiduan, Li Jiaqi and Tong Jinnan.