Ajarayama Andesite

Ajarayama Andesite (Iwai, 1965) Muraoka and Hase, 1990

Invalid synonym: Ajarayama Andesite Member

Type locality: Mount Ajara, Owani city, Minamitsugaru county, Aomori prefecture
Post-caldera volcanic rocks
Volcanic rocks
Pliocene

Lithofacies: Calc-alkaline series
Lithofacies (Lava facies): Andesite lava
Lithofacies (Pyroclastic fall facies, Upper): Scoria, Pumice, Accidental fragments
Lithofacies (Pyroclastic fall facies, Lower): Andesitic volcanic bomb, Scoria
Sedimentary structures (Pyroclastic fall facies): Graded bedding

Thickness: ca. 100 - 150 m
Thickness (Pyroclastic fall deposit): ca. 6 m
Lower limit: Interfengered (Ikarigaseki Formation)

Ikarigaseki caldera
[ Upper ]
~~~~~~~~~~~~~~
Ajarayama Andesite
'''''''/,,,,,,
Ikarigaseki Formation
~~~~~~~~~~~~~~
Nijikai Tuff
~~~~~~~~~~~~~~
Mitsumori Andesite
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Mount Ajara, Hirakawa city - Owani city, Minamitsugaru county, Aomori pref.; Otakamori, Owani city, Minamitsugaru county, Aomori pref.; Futatsumori, Minbutai, Hirakawa city, Aomori pref.

Muraoka and Hase (1990) Geology of the Kuroishi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 124p. (in Japanese with English abstract 8p.)