Hassaki Fall Tephra

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Hassaki Fall Tephra Geshi and Takeuchi, 2012

Type locality: Hassaki, Shibukawa city, Gunma prefecture
Tephra
Haruna caldera-forming eruption
Pleistocene (ca. 50 ka)
Contemporaneous heterotopic facies: Shirakawa Pyroclastic Flow Deposit

Lithofacies: Orthopyroxene hornblende andesite pumice

Source: Haruna volcano
Mode of eruption: Plinian
Thickness: ca. 5 - 50 cm

Hr-HP Tephra
[ Upper ]
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Shirakawa Pyroclastic Flow Deposit / Hassaki Fall Tephra
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[ Lower ]

Younger Haruna volcano
[ Upper ]
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Futatsudake Lava
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Hr-FP Tephra
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Hr-FA Tephra
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Younger Haruna Volcanic Fan Deposit
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Mizusawayama Lava / Mizusawayama Pyroclastic Flow Deposit and Talus Deposit
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Somayama Lava
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Jagatake Lava
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Harunafuji Lava
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Hr-HP Tephra
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[ Lower ]

Haruna volcano
[ Upper ]
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Younger Haruna volcano
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Older Haruna volcano
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[ Lower ]

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

Distribution: Hassaki - Arima, Shibukawa city, Gunma pref.; Jumonji, Haruna town, Takasaki city, Gunma pref.

Geshi and Takeuchi (2012) Geology of the Haruna San District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 79p. (in Japanese with English abstract 3p.)