Yokooyama Trachyte

[ Top ] [ Japanese ]

Yokooyama Trachyte

Volcanic rocks
late Miocene
Contemporaneous heterotopic facies: Shirashima Rhyolite

Lithofacies: Trachyte lava
Sedimentary structures: Porphyritic structures

Upper part (North)
[ Upper ]
--------------
Shirashima Rhyolite / Yokooyama Trachyte
--------------
[ Lower ]

Upper part (South)
[ Upper ]
--------------
Takugi Trachyandesite / Terayama Shoshonite
--------------
Yokooyama Trachyte
--------------
[ Lower ]

Omosu Formation
[ Upper ]
~~~~~~~~~~~~~~
Upper part
--------------
Middle part
--------------
Lower part
--------------
[ Lower ]

Oki-Dogo island, Shimane pref.
[ Upper ]
~~~~~~~~~~~~~~
Omosu Formation
--------------
Tsuma Formation
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Mount Yokooyama - Kitayama - Dairyo - Yui - Cape Nagumisaki - Kaminishi - Shirashima seashore - Kumi - Dai - Mount Sakiyama, Okinoshima city, Oki county, Shimane pref.
Tephra: Pyroclastic Rock 7, Pyroclastic Rock 8, Pyroclastic Rock 9, Pyroclastic Rock 10, Pyroclastic Rock 11

Yamauchi et al. (2009) Geology of the Saigo District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 118p. (in Japanese with English abstract 3p.)