Home Multi-Country Search About Admin Login
Cenozoic
Cretaceous
Jurassic
Triassic
Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
Neoproterozoic
Mesoproterozoic

Search by
Select Region(s) to search
Hold Ctrl (Windows/Linux) or Command (Mac) to select multiple
Gumu Formation

Gumu Fm


Period: 
Ordovician, Silurian

Age Interval: 
Terminal Ordovician to Llandovery (O3-S1), (67, 68, 69)


Province: 
Guangxi, Guangdong

Type Locality and Naming

It was named by Guangdong Party of Geological Survey at Gumu village, Yunfu County, Guangdong Province. The paratype section is located at the Qiping Tree Farm, Cengxi County, Guangxi Zizhiqu. The name of Lingshan Group was rejected by Yin Baoan (eds., 1997).

Synonym: (古墓组)


Lithology and Thickness

The formation is dominated by fine-grained sandstone, litharenite and siltstone, interbedded with shale. The thickness of the formation is over 300 m.


Lithology Pattern: 
Fine-grained sandstone


Relationships and Distribution

Lower contact

It is contacted conformably with the underlying Dagangding Fm of Upper Ordovician.

Upper contact

It is contacted conformably with the overlying Hepu Fm

Regional extent

It is exposed in the Fangchenggang, Qinzhou, Hepu, Bobai, Luchuan, Yulin, Beiliu, Rongxian, Cengxi areas of southeastern Guangxi, and Yunfu area of Guangdong. The thickness and the material of litharenite are increased gradually southwestward. The thickness can be up to 3295-4725 m at Qinzhou and Fangchenggang area.


GeoJSON

null

Fossils

The formation is rich in graptolite fossils, includes Normalograptus persculptus, Akidograptus acuminatus, Pristiograptus cyphus, Demirastrites triangulatus, D. convolutus, Monograptus sedgwickii, Spirograptus turriculatus, S. crispus, Monoclimacis griestoniensis, Stomatograptus grandis, Oktavites spiralis etc., and trilobite Encrinuroides sp., Coronocephalus rex, etc. and brachiopoda Nalivkinia sp., Zygospraella sp. Rhynchonella sp., etc., at some certain levels.


Age 

Normalograptus persculptus implies begins in mid-Hirnantian

Age Span: 

    Beginning stage: 
Hirnantian

    Fraction up in beginning stage: 
0.5

    Beginning date (Ma): 
444.14

    Ending stage: 
Sheinwoodian

    Fraction up in the ending stage: 
0.0

    Ending date (Ma):  
432.93

Depositional setting


Depositional pattern:  


Additional Information


Compiler:  

Wang Chuanshang and Wang Xiaofeng