Wakahata Formation

[ Top ] [ Japanese ]

Wakahata Formation Shibata, 1962

Type locality: Wakahata, Taiwa city, Kurokawa county, Miyagi prefecture
Coherent formation
Pleistocene
Intruded by: Kamikadajin Lava

Sedimentary facies: Lacustrine (Diatoms)
Sedimentary facies: Caldera lake
Lithofacies: Sandstone, Siltstone, Pumice tuff
Lithofacies (Minor): Mudstone

Thickness: 150 - 200 m
Upper limit: Unconformity (Akakuzureyama Lava, Arakawa Pyroclastic Rocks)
Lower limit: Conformity (Miyatoko Tuff Member)

Nanatsumori volcano
[ Upper ]
--------------
Ohatayama Pyroclastic Rocks
--------------
Akakuzureyama Lava / Ohatayama Lavas / Kamikadajin Lava
--------------
Nanatsumori Lava
--------------
Wakahata Formation
--------------
Miyatoko Tuff Member
--------------
[ Lower ]

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

Distribution: Wakahata - Neko - Danhara, Daiwa city, Kurokawa county, Miyagi pref.; Ojojihara, Shikama city, Kami county, Miyagi pref.
Fossils (Plants): Acer cf. diabolicum, Ulmus cf. carpinoides
Fossils (Freshwater diatoms): Cepephora martyi, Cocconeis placentula, Cymbella turgida, Gomphonema sp., Melosira granulata, Melosira roeseana, Nitzschia sp., Stauroneis parpula, Stephanodiscus astraea

Miyamoto et al. (2013) Jour. Geol. Soc. Japan, vol.119, Supplement, pp.27-46 DOI
Kitamura et al. (1983) Geology of the Yoshioka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 50p. (in Japanese with English abstract 5p.)