Older Obasute Mudflow Deposit

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Older Obasute Mudflow Deposit Kato and Akahane, 1986

Invalid synonym: Obasute Mudflow Deposit

Type locality: Obasute - Mine, Koshoku, Chikuma city, Nagano prefecture
Coherent formation
Sector collapse deposit of Mitsumineyama volcano
middle Pleistocene (13,550 yBP, ¹⁴C)

Sedimentary facies: Mudflow deposit
Lithofacies:

Thickness: 10 - 20 m
Thickness (Sandy silt, Clay): 1 - 1.5 m
Upper limit: Unconformity (Sanokawa Fan Deposit, Younger Obasute Mudflow Deposit)
Lower limit: Unconformity (Kuwabara Volcanics, Susobana Formation, Mitsumineyama Volcanics)

Older Obasute Mudflow Deposit
[ Upper ]
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Upper part
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Sandy silt - Clay
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Lower part
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[ Lower ]

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

Distribution: Obasute - Mine, Koshoku, Chikuma city, Nagano pref.

Kato and Akahane (1986) Geology of the Nagano District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 120p. (in Japanese with English abstract 5p.)
Kato (1980) Geology of the Sakaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 57p. (in Japanese with English abstract 5p.)