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Yangmeilong Formation

Yangmeilong Fm

Period: 
Triassic

Age Interval: 
Middle-late Late Triassic, (TJ95a, TJ95b)


Province: 
Hunan

Type Locality and Naming

The reference locality is located at Baoyuan River in the third capital of Zixing, Hunan. Tan Xichou named it "Yanmeilong stratum" in 1939.

Synonym:


Lithology and Thickness

Lower part of this group is dark gray thin to thick quartz sandstone and a small amount of silty mudstone with 2 to 3 layers of coal, with a thickness of 117 m. Upper part of this Formation is dominated by siltstone and silty mudstone, with 4 to 6 layers of fine sandstone and coal, with a thickness of 65.4 m.


Lithology Pattern: 
Fine-grained sandstone


Relationships and Distribution

Lower contact

Gray conglomerate the coarse-grained quartz sandstone at the top of this Formation is in pseudo-conformable contact with fine conglomerate at the bottom of Tanglong Fm

Upper contact

Regional extent

This Formation is mainly distributed in the areas of Zixing and Yizhang in Hunan, missing from the east to Rucheng, and no distribution to the north to Yongxing, Chaling and other places, with little lithological change.


GeoJSON

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Fossils

Plants: Ptilozamites chinensis, Clathropteris meniscioides, Marattiopsis sp., Anthrophyopsis crassinervis and so on; Bivalves: Jiangxiella subovata, J. elliptica, Palaeocardia sp., Mytilus lamellose etc.


Age 

Just like Chutanlong Fm, the Yangmeilong Fm in the Regional Geology of Hunan Province in 1988 includes the coarse clastic rock layers in the middle and upper parts of the predecessor's "Yangmeilong and Chutanlong layers"; the stratum lies between the overlying Upper Triassic Tanglong Fm (now considered as Early Jurassic in this lexicon) gravel sandstone and the underlying Chutanlong Fm quartz sandstone, and the age is the middle of the Late Triassic. Schematic stratigraphic column shows span of Norian-Rhaetian.

Age Span: 

    Beginning stage: 
Norian

    Fraction up in beginning stage: 
0.0

    Beginning date (Ma): 
227.30

    Ending stage: 
Rhaetian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
201.36

Depositional setting


Depositional pattern:  


Additional Information


Compiler:  

Zhou Huiqin, Zhang Shiyan and Tong Jinnan.