Iyo Unit

[ Top ] [ Japanese ]

Iyo Unit Banno et al., 2010

Invalid synonym: Izushi Formation

High P/T metamorphic rocks (ca. 360 degree C, 0.54 - 0.61 GPa)
Deposition (Limestone): Late Triassic (Conodonts)
Deposition (Basalt): Jurassic (ca. 155 Ma)
Deposition (Gabbro): Jurassic (139 - 135 Ma, U-Pb)
Protolith: Late Cretaceous (ca. 90 Ma, K-Ar)
Metamorphism: Late Cretaceous (ca. 90 - 77 Ma, K-Ar)
Correlation (Upper): Minawa Unit
Correlation (Lower): Kawaguchi Formation, Koboke Unit
Intruded by: Rhyolite - Dacite dikes

Metamorphic facies (Lower): Chlorite zone
Metamorphic facies: Pumpellyite-Actinolite facies, Epidote-Blueschist facies
Lithofacies (Upper): Mafic schist
Lithofacies (Upper, Minor): Siliceous schist, Psammitic schist, Meta-gabbro
Lithofacies (Lower): Pelitic schist
Lithofacies (Lower, Minor): Mafic schit, Psammitic schist, Siliceous schist, Calcareous schist

Thickness: 3,500 m or thicker
Thickness (Upper): ca. 700 - 1,650 m
Thickness (Lower): ca. 400 - 1,200 m
Upper limit: Thrust fault (Kikitsu Unit)

Iyo Unit
[ Upper ]
/--/--/--/--/-
Karasaki Mylonite
/--/--/--/--/-
[ Lower ]

Sanbagawa Metamorphic Rocks (eastern Ozu, Ehime pref.)
[ Upper ]
/--/--/--/--/-
Nakaidani Unit
/--/--/--/--/-
Fukuoka Unit
/--/--/--/--/-
Kannan Unit = Mikabu Unit
/--/--/--/--/-
Ozu Unit
/--/--/--/--/-
Uchiko Unit
/--/--/--/--/-
Iyo Unit
/--/--/--/--/-
[ Lower ]

Sanbagawa Metamorphic Rocks (western Ozu, Ehime pref.)
[ Upper ]
/--/--/--/--/-
Hijikawa Unit
/--/--/--/--/-
Mikabu Unit
/--/--/--/--/-
Ozu Unit
/--/--/--/--/-
Uchiko Unit
/--/--/--/--/-
Kikitsu Unit
/--/--/--/--/-
Iyo Unit
/--/--/--/--/-
[ Lower ]

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

Distribution: Hizuchi - Noji - Mount Doganaru - Kawatsuji, Yawatahama city, Ehime pref.; Hijikawa river - Maoku - Tsubai - Nishimine - Nemotokoshitoge pass - Odagiwa - Iyonagahama town - Ikata town - Mount Saitoyama - Yamatogawa river - Kushu - Mount Harikiyama - Izumi - Mount Joshinyama - Isaki - MIyauchi - Hirobaya - Mount Kosenjisan - Kuronta - Kamisukai - Tadokoro, Ozu city, Ehime pref.; Kaminada, Iyo city, Ehime pref.
Fossils (Calcareous schist, Conodonts): Epigondolella abneptis, Epigondollela multidentata

Miyazaki (2024) Geology of the Iyo-Nagahama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 155p. (in Japanese with English abstract 5p.)
Banno et al. (2010) Geology of the Ozu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 58p. (in Japanese with English abstract 2p.)