Mainosawa Sandstone Member

Mainosawa Sandstone Member (Otuka, 1934) Tuzino et al., 2018

Invalid synonym: Mainosawa Sands, Maisawa Sandstone Member of volcanic fragments

Type locality: Mabechi river, Maizawa, Ninohe city, Iwate prefecture
Coherent formation
middle Miocene

Sedimentary facies: Shallow marine
Sedimentary facies (Lower): Slump deposit, Slump scar fill deposit
Lithofacies: Sandstone
Lithofacies (Minor): Siltstone, Glauconite
Sedimentary structures (Upper): Foreset cross-stratification, Hummocky cross-stratification
Sedimentary structures (Lower): Slump structures

Thickness: 60 - 80 m
Upper limit: Unconformity (Hinosawa Conglomerate Member)
Lower limit: Conformity (Yotsuyaku Formation, Aikawa Volcanic Rock Member)

Suenomatuyama Formation
[ Upper ]
~~~~~~~~~~~~~~
Mainosawa Sandstone Member
--------------
Aikawa Volcanic Rock Member / Nakuidake Volcanic Rock Member
--------------
Itukamati Sandstone Member
--------------
Anausi Conglomerate Member
--------------
[ Lower ]

Shiratorigawa Group
[ Upper ]
~~~~~~~~~~~~~~
Suenomatuyama Formation
--------------
Kadonosawa Formation
--------------
Yotsuyaku Formation
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Mabechi river - Namiuchi pass, Maizawa, Ninohe city, Iwate pref.
Fossils (Bivalves): Chlamys cosibensis, Chlamys cf. kitamurai, Patinopecten kimurai
Fossils (Trace fossils): Thalassinoides isp.

Tuzino et al. (2018) Geology of the Ichinohe District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 161p. (in Japanese with English abstract 4p.)