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East Oshima clastics Formation
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East Oshima clastics Fm base reconstruction

East Oshima clastics Fm


Period: 
Jurassic

Age Interval: 


Province: 
Hokkaido

Type Locality and Naming

Rebun-Kabato Sub-belt and Oshima Belt

Synonym:


Lithology and Thickness

Terrigenous clastic rocks (mainly sandstone and mudstone) (Kawamura et al. 1986,2000). Sandstones in the Oshima Belt are arkosic, being rich in quartz and feldspars and poor in lithic fragments, which consist mainly of granite, felsic volcanic and sedimentary rocks (Tajika et al. 1984; Kusunoki 1996; Kawamura et al. 2000). According to Kawamura et al. (2000) and Roser et at. (2003), their highly silicic whole-rock composition suggests a felsic continental source. Kawamura et al. (2000) also reported pyrope-rich detrital garnet, presumably of granulite origins, and SHRIMP U-Pb ages of c. 1800 and 2500 Ma detrital zircons from a sandstone sample. Based on these data, they considered their source to have been the North China Craton. Kusunoki (1996) and Kusunoki & Musashino (2001) compared the modal and chemical compositions of the Oshima Belt sandstones with the Taukha Terrane of the south Sikhote-Alin, far-east Russia, and suggested they share the same sedimentary provenances.


Lithology Pattern: 
Coarse-grained sandstone


Relationships and Distribution

Lower contact

Oshima tuff Fm (conformable)

Upper contact

Rebun Gr or Kumaneshir Gr (unconformable) in Rebun-Kabato Sub-belt; West Oshima Plutons Fm (unconformable) in West Oshima Belt.

Regional extent

Rebun-Kabato Sub-belt and Oshima belt.


GeoJSON

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Fossils


Age 


Age Span: 

    Beginning stage: 
Oxfordian

    Fraction up in beginning stage: 
0

    Beginning date (Ma): 
161.53

    Ending stage: 
Tithonian

    Fraction up in the ending stage: 
0.682

    Ending date (Ma):  
145.05

Depositional setting



Depositional pattern:  


Additional Information



Compiler:  

Hayato Ueda. 2g Hokkaido. in Moreno, T., WALLIS, S., Kojima, T. & Gibbons, W. (Eds) 2016. The Geology of Japan. Geological Society. London. 201-220.