Iwa Lavas

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Iwa Lavas (Nagai et al., 2006) Oikawa and Ishizuka, 2011

Invalid synonym: Iwa Lava Group

Type locality: Iwa, Manazuru city, Ashigarashimo county, Kanagawa prefecture
Volcanic rocks
Middle Pleistocene (ca. 0.22 - 0.18 Ma, Tephra)
Correlation: Soda Loam

Sedimentary facies (Upper): Terrestrial
Sedimentary facies (Lower): Marine
Lithofacies: Clinopyroxene orthopyroxene andesite - dacite lava
Lithofacies (Minor): Scoriaceous pyroclastic breccia, Tuff breccia, Welded pyroclastic rocks
Lithofacies (Lava, Upper): Aa lava
Lithofacies (Lava, Lower): Hyaloclastite

Thickness (Lava, A unit): 20 m or thicker
Upper limit: Unconformity (Honkomatsu Lava, Manazurumisaki Lava, Makuyama Lava)

Hakone volcano (Manazuru)
[ Upper ]
~~~~~~~~~~~~~~
Makuyama Lava
~~~~~~~~~~~~~~
Manazurumisaki Lava
~~~~~~~~~~~~~~
Honkomatsu Lava
~~~~~~~~~~~~~~
Shiraiso Lavas
~~~~~~~~~~~~~~
Iwa Lavas
~~~~~~~~~~~~~~

>Uminodaira Lavas

~~~~~~~~~~~~~~

[ Lower ]

Hakone volcanoes
[ Upper ]
+__+__+__+__+_
Hakone volcano
~~~~~~~~~~~~~~
Yugawara volcano
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Iwa, Manazuru city, Ashigarashimo county, Kanagawa pref.; Mount Hoshigayama - Yoshihama - Mount Nangosan, Yugawara city, Ashigarashimo county, Kanagawa pref.
Tephra: Tm-26, Tm-27

Oikawa and Ishizuka (2011) Geology of the Atami District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 61p. (in Japanese with English abstract 3p.)