Usugatani Group

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Usugatani Formation Hirayama et al., 1956

Type locality: Usugatani, Naga city, Naga county, Tokushima prefecture
Coherent formation
Middle Triassic, Ladinian - Anisian (Radiolarians, Ammonoids)
Correlation: Zohoin Formation

Sedimentary facies: Shallow marine
Lithofacies: Mudstone, Sandy mudstone
Lithofacies (Minor): Sandstone

Thickness: ca. 85 - 200 m or thicker

Kochigatani Group
[ Upper ]
~~~~~~~~~~~~~~
Umegatani Formation
?--?--?--?--?-
Sabudani Formation
?--?--?--?--?-
Usugatani Formation
/--/--/--/--/-
[ Lower ]

Kurosegawa Belt (Sakashu, Tokushima pref.)
[ Upper ]
/--/--/--/--/-
Sakashu Group
~~~~~~~~~~~~~~
Kochigatani Group
/--/--/--/--/-
Haigyu Group
/--/--/--/--/-
Mitaki Igneous Rocks
/--/--/--/--/-
Miyagadani Metamorphic Rocks
/--/--/--/--/-
[ Lower ]

Chichibu Belt
[ Upper ]
/--/--/--/--/-
Kurosegawa Belt
/--/--/--/--/-
Northern Chichibu Belt
/--/--/--/--/-
Southern Chichibu Belt
/--/--/--/--/-
[ Lower ]

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

Distribution: Usugatani - Shimoyochi - Higashisemitani - Kominono - Nagayasu, Naka city, Naka county, Tokushima pref.
Fossils (Ammonoids): Protrachyceras cf. pseudoarchelaus
Fossils (Shellfishes): Daonella hiratai, Daonella kotoi

Hara et al. (2014) Geology of the Kitagawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 72p. (in Japanese with English abstract 4p.)