Niitsuki Formation

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Niitsuki Formation Onuki, 1956

Type locality: Niitsuki, Kesennuma city, Miyagi prefecture
Volcanic rocks
A member of Volcano-plutonic complex with Orikabe Plutonic Complex
Early Cretaceous, Hauterivian (121 Ma, K-Ar)
Correlation: Kanaigaura Formation
Intruded by: Orikabe-1a type, Sasamori type, Diorite porphyry, Dolerite, Granophyre

Lithofacies: Pigionite-series, K₂O-rich high alumina series
Lithofacies: Calc-alkalinic (Continental margin - Island arc)
Lithofacies: Andesite volcaniclastic rocks, Lava, Basaltic lava, Pyroclastic rocks
Lithofacies (Minor): Andesite tuff breccia, Tuff, Basaltic lava, Pyroclastic rocks

Distribution (NNW - SSE): ca. 20 km
Lower limit: Unconformity (Saragai Group)

Niitsuki Formation
[ Upper ]
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Andesite-basalt Lava and Pyroclastic Rocks Member
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Andesitic Pyroclastic Rock Member
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[ Lower ]

Kesennuma, Miyagi pref.
[ Upper ]
?--?--?--?--?-
Yokonuma Formation
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Kanaigaura Formation
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Niitsuki Formation
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Nagasaki Formation
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Isokusa Formation
?--?--?--?--?-
[ Lower ]

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

Distribution: Niitsuki, Kesennuma city, Miyagi pref.; Iwate pref.

Takeuchi and Mikoshiba (2002) Geology of the Senmaya District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 76p. (in Japanese with English abstract 3p.)
Kambe and Shimazu (1961) Kesennuma, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 73p. (in Japanese with English abstract 16p.)