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Mikabu Unit, Mikabu Green Rocks (Koto, 1888)

Invalid synonym: Shizutama zone

The name of this geological unit, Mikabu, is different from the name of the type locality.

There is an opinion that this unit and Kashiwagi Unit are separated as Mikabu Belt.

• Type locality: Mount Mikabo, Kanna city and Fujioka city, Gunma prefecture
• High P/T metamorphic rocks (0.65 GPa or larger)
• Deposition: Middle - Late Jurassic
• Deposition (Shale): Jurassic (Radiolarians)
• Deposition (Gabbro): Late Jurassic (155 Ma, FT)
• Deposition (Ultramafic rocks): Late Jurassic (ca. 150 Ma, K-Ar)
• Metamorphism (Greenschist facies): Late Cretaceous (83.5 - 78.3 Ma, K-Ar; 98 - 96 Ma, Ar-Ar)
• Accretion: Early Cretaceous (130 - 100 Ma)
• Correlation: Kannan Unit

• Sedimentary facies: Submarine volcano. Mantle material-deficient plume-type ophiolite
• Metamorphic facies: Pumpellyite-Actinolite facies, Greenschist facies, Blueschist facies
• Metamorphic facies: Chlorite zone
• Lithofacies (Upper): Mudstone, Siliceous mudstone
• Lithofacies (Upper, Minor): Gabbro, Basalt (Lava, Hyaloclastite), Ultramafic rocks (Serpentinite)
• Lithofacies (Lower): Gabbro, Basalt lava (Pillow lava), Dolerite, Hyaloclastite, Volcaniclastic rocks
• Lithofacies (Lower, Minor): Chert, Siliceous mudstone
• Lithofacies (Minor): Pelitic schist, Limestone, Amphibolite, Serpentinite, Dunite, Wehrlite

• Thickness: 300 - 1,700 m
• Upper limit: Aridagawa Tectonic Line (Wakayama) (Chichibu Belt), Thrust fault (Ishimakisan Unit, Suse Unit, Kashiwagi Unit, Akaragi Unit)
• Lower limit: Thrust fault (Kinouzu Unit)

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

• Distribution: Mount Mikabo, Gunma pref.; Yuzurihara, Onishi, Fujioka city, Gunma pref.; Iyo - Taiho - Asahine - Sadamine river, Higashichichibu city, Saitama pref.; Kiroko - Suguro, Ogawa city, Hiki county, Saitama pref.; Akiyama - Yatsu - Tomita - Nishinoiri, Yorii city, Osato county, Saitama pref.; Sadamine pass, Chichibu city, Saitama pref.; Mount Hotosan, Nagatoro, Chichibu city, Saitama pref.; Mount Minoyama, Minano city, Chichibu county, Saitama pref.; Mount Kichijosan - Lake oharaike (Lake Goyoko), Shinshiro city, Aichi pref.; Teriyama - Mount Gongenyama, Toyohashi city, Aichi pref.; Himeshima island - Katahama - Mount Kasayama - Shiroya - Yamanokami - Makusa - Ishigami - Furuta - Kameyama - Hatsutachi dam - Irago - Cape Iragomisaki, Tahara city, Aichi pref.; Higashikuroda - Bessho - Shibukawa - Kawaure - Kamishinto - Tazawa - Kokuzo - Shizutama, Inasa town, Hamana ward, Hamamatsu city, Shizuoka pref.; Kanaya - Shimizu, Aridagawa city, Arida county, Wakayama pref., Ozu city, Ehime pref.; Jizoji, Tosa city, Tosa county, Kochi pref.; Yoshinobu - Mount Taiyama, Motoyama city, Nagaoka county, Kochi pref.

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