Katsuura Mudstone Member

[ Top ] [ Japanese ]

Katsuura Mudstone Member (Nakano, 1953) Noda et al., 2021

Invalid synonym: Katsuura Shale, Katsuura Formation

Type locality: Mount Hachiminezan, Manno city, Nakatado county, Kagawa prefecture
Coherent formation
Izumi sedimentary basin
Forearc basin associated with strike-slip fault related to Median Tectonic Line
Late Cretaceous, middle Campanian (79.3 Ma, U-Pb)

Sedimentary facies: Lower submarine fan, Sedimentary basin floor
Sedimentary facies: Low-density turbidity current sheet flow
Lithofacies (Upper): Interbedded sandstone and mudstone
Lithofacies (Middle): Mudstone, Mudstone-dominant interbedded sandstone and mudstone
Lithofacies (Middle, Minoe): Felsic tuff, Sandstone, Tuffaceous sandstone, Sandstone-dominant interbedded sandstone and mudstone
Lithofacies (Lower): Mudstone, Mudstone-dominant interbedded sandstone and mudstone
Sedimentary structures: Graded bedding

Thickness: 1,300 m or thicker
Lower limit: Bottom of mudstone-dominant interbedded sandstone and mudstone
Lower limit: Transitional (Nagoro Mudstone Member)

Horita Formation
[ Upper ]
--------------
Katsuura Mudstone Member
--------------
Nagoro Sandstone Member
--------------
[ Lower ]

Main facies (Sanuki mountains, Tokushima pref.)
[ Upper ]
'''''''/,,,,,,
Bandodani Formation
--------------
Higaidani Formation
--------------
Horita Formation
--------------
Takikubo Formation
--------------
[ Lower ]

Izumi Group
[ North ]
~~~~~~~~~~~~~~
Northern marginal facies
~~~~~~~~~~~~~~
Main facies
~~~~~~~~~~~~~~
Southern facies
~~~~~~~~~~~~~~
[ South ]

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

Distribution: Mount Hachiminezan - Masuzu - Haze, Manno city, Nakatado county, Kagawa pref.; Takinooku - Shibau - Kochidanigawa river, Miyoshi city, Tokushima pref.
Fossils: Ammonoids (Baculites sp.)
Fossils (Radiolarians): Amphipyndax pseudoconulus, Amphipyndax tylotus, Archaeodictyomitra lamellicostata, Dictyomitra densicostata, Dictyomitra koslovae, Dictyomitra multicostata

Noda et al. (2021) Geology of the Ikeda District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 150p. (in Japanese with English abstract 5p.)