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.