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Mahuanggou Formation

Mahuanggou Fm

Period: 
Mesoproterozoic

Age Interval: 
Changchengian (Statherian) Ch (12a)


Province: 
Qinghai

Type Locality and Naming

North-central Qinghai. The Mahuanggou Fm was named by WangYunshan et al. in 1980. The typical section is situated in Mahuang valley in Olongbluk Mountain in Wulan County, Qinghai Province. Lower formation of Quangji Gr

Synonym: （麻黄沟组）


Lithology and Thickness

The Mahuanggou Fm is composed of grayish purple alternating with greenish gray and white gray conglomerate, pebbly sandstone, medium to coarse-grained sandstone and fine conglomerate. The upper part, grayish purple, greenish yellow and white gray coarse-grained feldspathic quartzose sandstone, which bears abundant K-feldspar and obvious oblique beddings. The thickness varies from 431 to 668 m.


Lithology Pattern: 
Coarse-grained sandstone


Relationships and Distribution

Lower contact

It rests unconformably on the hornblende plagio-schist of the Dakendaban Gr

Upper contact

The top is conformably overlain by the Kubaimu Fm (Gubaimu Fm)

Regional extent

North-central Qinghai. The Mahuanggou Formation is distributed in Olongbluk Mountain, Quanji Mountain and Anba areas in north Qaidam Basin.


GeoJSON

null

Fossils

It yields microplants Trematosphaeridium cf. holtedahlii etc.


Age 

LA-MC-ICPMS U-Pb date of 1640±5 Ma is from zircon in the tuff of the overlapping Hongzaoshan Fm (Zhang Haijun et al., 2016). Schematic stratigraphic column shows it spanning the early Changchengian (early Statherian)

Age Span: 

    Beginning stage: 
Statherian

    Fraction up in beginning stage: 
0.0

    Beginning date (Ma): 
1,800.00

    Ending stage: 
Statherian

    Fraction up in the ending stage: 
0.3

    Ending date (Ma):  
1,740.00

Depositional setting


Depositional pattern:  


Additional Information


Compiler:  

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