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Xiong'er Gr

Xiong'er Gr

Period: 
Mesoproterozoic

Age Interval: 
Changchengian (Statherian) Ch (20,21)


Province: 
Henan, Shaanxi, Shanxi

Type Locality and Naming

Northwest Henan. The Xiong'er Gr was named by the Qinling Party of Regional Geological Survey, Ministry of Geology in 1959. The named place is located at Xiong'er Mountain, western Henan Province.

Synonym: （熊儿群）, Xiyanghe Gr, Xiaoshan Gr, Hekou Gr, Luo'ao Gr, Liuzhuang Fm are all different names for Xiong'er Gr. According to naming priority principle, these stratigraphic names should be abolished.


Lithology and Thickness

The Xiong'er Gr is dominated by intermediate volcanic lava and minor clastic rock of continental-marine facies. It is subdivided into Dagushi Fm of fluviatile clastic rock; Xushan Fm of andesite; Jidanping Fm of dacite-porphyry sandwiched with volcaniclastic rock and Majiahe Fm of intermediate-basic-acid volcanic lava. [Details are in the entries for those component formations.] The total thickness is recorded to 5089 m.


Lithology Pattern: 
Volcanics


Relationships and Distribution

Lower contact

The group is in unconformable contact with underlying Taihua Gr of Archean Erathem or Paleoproterozoic Erathem.

Upper contact

The top part is conformably overlain by the Gaoshanhe Fm in Shannxi Province or by the Ruyang Gr (Bingmagou Fm) in Henan Province.

[Figure: The boundary between the Xiong’er Gr. and the overlying Gaoshanhe Gr]

Regional extent

NE Shaanxi-NW Henan-S. Shanxi. The Xiong'er Group spreads in Lushi, Luoning, Songxian, Lushan, Jiyuan counties, Henan Province, Luonan, Shaanxi Province and Yuanqu, Shanxi Province.


GeoJSON

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Fossils


Age 

A volcanic rock sample taken from the Majiahe Fm by Sun Shu in 1977 was dated by Rb-Sr whole-rock isochron at 1710±73 Ma; the multi-zircon group taken from volcanic rock of the Xushan Fm was dated by conventional U-Pb dating at 1829±41 Ma (Sun Dazhong in 1993). The multi-zircon was measured by group; among them, two groups were dated at 1826 ± 32 Ma. Mono-zircon measured by ion-microprobe mass spectrometer (IMMS) gave the measured weight average age at 1840±14 Ma. Schematic stratigraphic column shows as early Changchengian (early Statherian); and each of the 4 formations are given quasi-equal spans for the graphic display.

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.