Iizuna Basalts

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Iizuna Basalts Hayatsu, 1985

Invalid synonym: Kurotaki Scoria, Nishizawa Lava, Menoyama Lava

Type locality: Naruiwa, Tomita, Nagano city, Nagano prefecture
Volcanic rocks
Pleistocene (0.22, 0.18 Ma, K-Ar)

Lithofacies: Basalt scoria fall deposit, Lava (4 flow units), Pyroclastic deposits

Thickness: 50 m or thicker
Thickness (A unit): Several tens - 120 cm
Upper limit: Unconformity (Iizunayama Lava)
Lower limit: Unconformity (1st stage)

Stratovolcano stage
[ Upper ]
~~~~~~~~~~~~~~
Morozawa Pyroclastic Flow Deposit
~~~~~~~~~~~~~~
Kasayama Lava
~~~~~~~~~~~~~~
Iizunayama Lava
~~~~~~~~~~~~~~
Iizuna Pyroclastic Flow Deposit
~~~~~~~~~~~~~~
Iizuna Basalts
~~~~~~~~~~~~~~
[ Lower ]

2nd stage
[ Upper ]
~~~~~~~~~~~~~~
Lava dome stage
~~~~~~~~~~~~~~
Caldera stage
~~~~~~~~~~~~~~
Stratovolcano stage
~~~~~~~~~~~~~~
[ Lower ]

Iizuna volcano
[ Upper ]
~~~~~~~~~~~~~~
2nd stage
~~~~~~~~~~~~~~
Mure Debris Avalanche Deposit
~~~~~~~~~~~~~~
1st stage
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Naruiwa, Tomita, Nagano city, Nagano pref.; Mount Meno, Nagano city, Nagano pref.

Nagamori et al. (2003) Geology of the Togakushi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 109p. (in Japanese with English abstract 3p.)