Arakura Formation

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Arakura Formation (Tamura et al., 1984) Ozaki and Sugiyama, 2018

Invalid synonym: Senshiro Formation

Type locality: Hayakawa river, Arakura, Hayakawa city, Minamikoma county, Yamanashi prefecture
Volcanic rocks
Miocene
Correlation: Jikkoku Formation
Intruded by: Andesite dykes

Sedimentary facies: Marine
Lithofacies: Andesite - Basalt volcaniclastic rocks, Reworked volcaniclastic rocks, Lava
Sedimentary structures: Parallel stratification, Sole marks
Paleocurrent: West to East

Thickness: 1,300 m or thicker
Upper limit: Conformity (Oharano Formation)

Kushigatayama Subgroup (Western part)
[ Upper ]
--------------
Arakura Formtion
~~~~~~~~~~~~~~
[ Lower ]

Kushigatayama Subgroup (Eastern part)
[ Upper ]
~~~~~~~~~~~~~~
Fujimiyama Formation
~~~~~~~~~~~~~~
Jikkoku Formation
~~~~~~~~~~~~~~
[ Lower ]

Koma Group
[ Upper ]
~~~~~~~~~~~~~~
Momonoki Subgroup
-------~~~~~~~
Kushigatayama Subgroup
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Arakura, Hayakawa city, Minamikoma county, Yamanashi pref.

Ozaki and Sugiyama (2018) Geology of the Minobu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 169p. (in Japanese with English abstract 7p.)