Hozumi Formation

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Hozumi Formation Shiba et al., 1989

Coherent formation
Trough basin-fill deposit at the collision boundary between Izu-Bonin-Mariana arc and Southwest - East Japan island arc
Back-arc basin volcanic activity at the back-arc basin of Izu-Bonin-Mariana arc
late Miocene - Pliocene (10.4, 10.1 Ma, FT)

Sedimentary facies: Marine
Lithofacies: Mudstone
Lithofacies (Minor): Mudstone-dominant interbedded sandstone and mudstone, Gravel-bearing mudstone, Conglomerate, Tuff breccia, Volcanic ash

Thickness: 300 m or thicker

Fujikawa Group (southern Shimizu, Shizuoka pref.)
[ Upper ]
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Z3 Formation
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Hozumi Formation
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Nagao Formation
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Kitataki Formation / Kashio Formation
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Isabu Formation / Yoshiwara Formation
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[ Lower ]

------ Conformity, ~~~~~~ Unconformity, ~~~--- Local unconformity, '''/,, Interfingered, :::::: Fault, /--/-- Thrust, +__+__ Ground surface, ?--?-- Unknown

Distribution: Hozumi - Hadaka - Michiyazu, Shizuoka city, Shizuoka pref.
Fossils (Foraminifeara): Acervulina inhaerens, Amphistegina radiata, Lepidocyclina (Nephrolepidina) angulosa, Lepidocyclina (Nephrolepidina) japonica, Lepidocyclina (Nephrolepidina) sumatrensis, Miogypsina (lepidosemicyclina) kotoi, Miogypsina (lepidosemicyclina) thecidaeformis, Sphaerogypsina globula, Victoriella sp.

Sugiyama and Shimokawa (1990) Geology of the Shimizu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 103p. (in Japanese with English abstract 8p.)