Iimuro Formation

Iimuro Formation (Otsuka, 1932) Oka et al., 1984

Type locality: Masugata - Iimuro, Tama ward, Kawasaki city, Kanagawa pref.
Coherent formation
Fore-arc basin sediments (Kazusa trough)

Sedimentary facies: Inner bay subjected to the influence of open sea
Lithofacies: Mudstone, Sandy mudstone

Thickness: ca. 5 - 45 m
Upper limit: Conformity (Takatsu Formation)
Lower limit: Transitional (Ozenji Formation), Conformity (Ikuta Formation)

Kazusa Group (central Tama hills)
[ Upper ]
~~~~~~~~~~~~~~
Takatsu Formation
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Iimuro Formation
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Ikuta Formation
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Ozenji Formation
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Kakio Formation
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Tsurukawa Formation
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Tsurukawa Formation
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Masugata - Iimuro - Mukogaokayuen, Tama ward, Kawasaki city, Kanagawa pref.; Utsukushigaoka, Aoba ward, Yokohama city, Kanagawa pref.; Takada town, Kohoku ward, Yokohama city, Kanagawa pref.
Fossils: Foraminifera
Fossils (Shellfishes): Acila divaricata, Acila insignis, Barnea japonica, Callithaca adamsi, Clementia vatheleti, Cultellus izumoensis, Macoma incongrua, Mactra sulcataria, Mactra cf. veneriformis, Nassarius gemmulatus, Natica severa, Nuculana pernula, Ostrea gigas, Paphia amabilis, Paphia schelliana, Periploma otohimeae, Polinices sagamiensis, Raeta pulchella, Suchium giganteum (<= Umbonium giganteum naganumanum)
Tephra: Yk, Noborito Pumice Group, Nb 1, Nb 2, Nishikubo (NK = Kd12, UNK-4), NB-Kd17

Suzuki et al. (2016) Jour. Geol. Soc. Japan, vol.122, no.7, pp.343-356, DOI
Suzuki and Murata (2011) Jour. Geol. Soc. Japan, vol.117, no.7, pp.379-397 DOI
Oka et al. (1984) Geology of the Tokyo-Seinambu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 148p. (in Japanese with English abstract 7p.)