Yoshigasawa Formation

Invalid synonym: Osawatoge Formation

Type locality: Yoshigasawa creek, Kitaite, Marumori city, Igu county, Miyagi prefecture
Coherent formation
Miocene
Correlation: Akashiba Formation

Sedimentary facies: Shallow marine (Shellfishes)
Sedimentary facies (Bottom, Osawa pass): Freshwater (Shellfishes)
Lithofacies: Sandstone, Interbedded sandstone and conglomerate

Thickness: ca. 130 m
Lower limit: Conformity (Hazama Formation, Upper Member of Kaneyama Formation), Abut unconformity (Karosan Formation)

Kakuda, Miyagi pref.
[ Upper ]
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Yoshigasawa Formation
--------------
Hazama Formation
--------------
Kaneyama Formation
'''''''/,,,,,,
Tenmyosan Volcanic Rocks
--------------
Shiote Formation
--------------
[ Lower ]

Somanakamura, Fukushima pref.
[ Upper ]
--------------
Yoshigasawa Formation
--------------
Hazama Formation
--------------
Ouchi Formation
~~~~~~~~~~~~~~
Ryozen Formation
~~~~~~~~~~~~~~
Tenmyosan Volcanic Rocks
'''''''/,,,,,,
Shiote Formation
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Kitaite - Sano, Marumori city, Igu county, Miyagi pref.; Ishikawaguchi, Kakuda city, Miyagi pref.
Fossils (Shellfishes): Anadara makiyamai, Cardium shiobaroense, Chlamys miyatokoensis, Cultellus izumoensis, Dosinia kaneharai, Felaniella usta, Glycymeris sp., Kaneharaia kaneharai, Laevicardium shiobarense, Lucinoma acutilineatum, Mercenaria chitaniana, Mercenaria y-iizukai, Mercenaria osyuensis, Mya cuneiformis, Nanaochlamys notoensis otutumiensis, Sinum yabei, Tellina protovenulosa
Fossils (Bottom, Osawa pass): Anodonta subjaponensis, Anodonta subjaponensis yokoyamai, Bulimus (Parafossarulus) osawaensis, Cristaria maroii, Inversidens kobayashiensis, Margaritifera perdahurica, Unio aff. uryuensis, Viviparus (Sinotaria) uryuensis

Fujita et al. (1988) Geology of the Kakuda District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 99p. (in Japanese with English abstract 9p.)