Sekirozan Formation

Sekirozan Formation (Mikami, 1955) Ueki et al., 2013

Invalid synonym: Sekirozan Conglomerate and Sandstone Member

Type locality: Doshigawa river, Lake Yokohamasuidochinsuiike - Abiko, Aoyama, Sagaihara city, Kanagawa prefecture
Coherent formation
Trough-fill deposit at the collision boundary between Oceanic arc of Paleo-Izu-Bonin arc (Ocean crust) and Honshu arc (Island arc)
late Miocene

Sedimentary facies: Marine
Sedimentary facies: Submarine fan
Lithofacies: Conglomerate
Lithofacies (Minor): Sandstone
Sedimentary structures: Slump structures, Ripples

Thickness: 70 - 500 m or thicker
Lower limit: Minor unconformity (Nakatsukyo Formation)

Aikawa Group
[ Upper ]
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Sekirozan Formation
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Nakatsukyo Formation
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Funazawa Formation
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Miyagase Formation
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[ Lower ]

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

Distribution: Lake Yokohamasuidochinsuiike - Abiko - Mount Sekirosan - Oiwashita - Sekidaira, Sagaihara city, Kanagawa pref.; Mukaihara, Hanbara - Shiokawa fall, Aikawa city, Aiko county, Kanagawa pref.
Fossils (Calcareous nannofossils): Discoaster berggrenii, Discoaster quinqueramus

Ueki et al. (2013) Geology of the Hachioji District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 137p. (in Japanese with English abstract 6p.)
Oka et al. (1979) Geology of the Fujisawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 111p. (in Japanese with English abstract 5p.)