List of geological units in Iwate prefecture

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A list of stratigraphic units, igneous bodies, and geological structures reported from Iwate prefecture, Tohoku region, Honshu island, Japan.

Photographs of geological units in Iwate prefecture

Cambrian (541-485.4 Ma)

Motai-Matsugadaira Belt

Motai Metamorphic Rocks: Sodenosawa Formation; Shimoide Formation; Kurodasuke Formation; Unoki Metamorphic Rock; Ohachimori Amphibolites; Takasunoyama Formation

Ordovician (485.4-443.4 Ma)

South Kitakami Belt

Hayachine Complex

Nakadake Serpentinite: Nakadake Body; Kasamoriyama Body; Yamayatoge Body

Kuromoriyama Amphibolite

Kagura Igneous Rocks: Nekosoko Body; Daisaku Zawa Body; Komegamorizawa Body; Kagura Body; Iwakurayama Body; Inugashirayama Body

Miyamori Complex

Ordovician-Silurian

South Kitakami Belt: Yakushigawa Formation

Silurian (443.4-419.2 Ma)

Hikami Granite

Shoboji Diorite

South Kitakami Belt: Nameirizawa Formation; Kawauchi Formation; Okuhinotsuchi Formation

Silurian-Devonian

South Kitakami Belt

Orikabetoge Formation: Shiraiwa Sandstone Mudstone Member; Ochiai Sandstone Conglomerate Member

Senjogataki Formation

Devonian (419.2-358.9 Ma)

Omori formation

South Kitakami Belt: Choanji Formation; Nakazato Formation; Ono Formation

Devonian - Carboniferous

South Kitakami Belt: Tobigamori Formation

Carboniferous (358.9-298.9 Ma)

Nedamo Belt

Nedamo Complex

Takinosawa Unit: Tateishi Conglomerate

Tsunatori Unit

Tateishi Schists

Hisadenaigawa Metamorphic Rocks

Onimaru formation

South Kitakami Belt: Karaumedate Formation; Takezawa Formation; Hikoroichi Formation; Nagaiwa Formation; Onimaru Formation; Odaira Formation; Arisu Formation; Shittakazawa Formation; Funakubo Formation; Odagoe Formation; Ozasa Formation; Nakazai Formation; Kogawa Formation; Yonesato Formation; Shiba Formation

Permian (298.9-252.17 Ma)

South Kitakami Belt

Nozuchi Formation

Uchikawame Formation

Toyoma Formation

Usuginu Formation: Usuginu Conglomerate

Kumonoueyama Formation

Higashifukakaya Formation

Ochiai Formation

Sakamotozawa Formation

Kanokura Formation: Iwahata Limestone Member

Triassic (252.17-201.3 Ma)

Kayamori group

North Kitakami Belt

Kuzumaki - Kamaishi Sub-belt: Kadoma Complex

South Kitakami Belt

Shizukawa-Hashiura Subbelt

Inai Group: Isatomae Formation; Fukkoshi Formation; Osawa Formation (Onnagawa formation); Hiraiso Formation

Saragai Group: Chonomori Formation; Shindate Formation

Jurassic (201.3-145.0 Ma)

North Kitakami Belt

Kuzumaki - Kamaishi Sub-belt: Otori Unit; Kassenba Formation; Seki Unit; Kuzumaki Formation; Gobakubo Formation; Nakatsugawa Complex; Toyomane Formation; Kuribayashi Formation; Kamaishi Formation; Hanawa Formation

Akka - Tanohata Sub-belt

Takayashiki Unit: Tachiusu Sandstone Member

Koshimeguri Formation

Cretaceous (145.0-66.0 Ma)

Kitakami mountains plutonic rocks

I Zone: Omoe Body; Oura Granite

II Zone

Hashikami Granite

Tanohata Granite

Marginal facies: Hornblende gabbro; M1; M2; M3; M4

Central facies: C1; C2; C3; C4; C5

Miyako Granite

Marginal facies: Miyako type; Osawa type; Ashiharahira type

Central facies: Shimotanabe type; Yamada type

III Zone: Hiraniwa Body; Sakainokami Body

IV Zone: Hinomiko Body; Himekami granites

V Zone

Kurihashi quartz diorite

Yoshihama type: Ys4; Ys3; Ys2; Ys1

Gabbroic rocks

Hitokabe Granite

Senmaya Tonalitic Pluton

VIa Zone

VIb Zone

Uchino Body

Orikabe Plutonic Complex

North body: Murone type; Tamogi type; Tsuwamonozawa type

Main body: Sasamori type; Orikabe type; Tokusenjo type

Hirota Quartz Monzonite

Kesengawa Granodiorite

Wakinosawa Granodiorite

Torigoe Granodiorite

Morioka granodiorite

South Kitakami Belt

Ofunato Subbelt

Massaki Group: Nagasaki Formation; Koyama Formation

Ofunato Group: Nagaiso Formation; Upper Hijochi Formation; Lower Hijochi Formation; Funagawara Formation; Takonoura Formation; Ryori Formation; Attari Formation

Uda dam granodiorite

Miyako Group: Hideshima Formation; Sakiyama Formation; Hiraiga Formation; Tanohata Formation; Aketo Formation; Raga Formation

Rikuchu Group: Harachiyama Formation; Omoto Formation

Kuji Group: Sawayama Formation; Kunitan Formation; Tamagawa Formation

Taneichi formation

Misaki Acidic Volcanic Rocks

Kurosaki Acidic Volcanic Rocks

Niitsuki Formation

Andesite-basalt Lava and Pyroclastic Rocks Member: Nagizawa Andesite Dykes

Andesitic Pyroclastic Rock Member

Cretaceous-Paleogene

Heizaki Pyroclastic Rocks

Eocene (56.0-33.9 Ma)

Jodogahama Rhyolites: Matsuhashi Rhyolite; Matsuhashi High-Mg Andesite; Nishoishi Rhyolite; Natsuyagawa Rhyolite; Futamata Rhyolite; Jodogahama Rhyolite; Kadogamiiwa Rhyolite; Hikime Dacite; Kariya Dacite; Matsuyama Rhyolite; Suzukuna Dacite; Yokozawa Dacite; Oguni Rhyolite; Chojamori Rhyolite; Tatsumarutoge Rhyolite

Kogawa Group

Oligocene (39.0-23.03 Ma)

Noda Group: Kuki Formation; Minato Formation

Oligocene-Miocene

Nisatai Formation

Miocene (23.03-5.33 Ma)

Inase Formation

Sahinai formation

Kotsunagizawa Formation: Okinazawa Basalt Member

Oishi Formation: Main member; Kawashiri Tuff Member

Oarasawa Formation

Tsunatori Formation

Suzukamogawa Formation: Takamoriyama Andesite Member

Kurosawa Formation

Hishinai Formation

Hanayama Formation

Maetsukamiyama Acidic Volcanic Rocks

Oidegawa Formation

Nishikozawa Formation

Maekawa Formation: Kosamuzawa Tuff Member

Orose Formation: Ichinonohara Tuff Member

Mizuyama Formation

Tayama formation

Iioka formation

Genbi formation

Genbi formation: Gogushi member

Shiratorigawa Group

Suenomatuyama Formation: Mainosawa Sandstone Member; Nakuidake Volcanic Rock Member; Aikawa Volcanic Rock Member; Itukamati Sandstone Member; Anausi Conglomerate Member

Kadonosawa Formation: Sikonai Siltstone Member; Tate Sandstone Member

Yotsuyaku Formation: Sukohata Siliciclastic Rock Member; Keiseitoge Volcanic Rock Member; Koiwai Mudstone Member; Matsukura Siliciclastic Rock Member

Sannohe Group

Shitazaki Formation: Kamassawa Sandstone and Siltstone Member; Kamimetoki Sandstone Member

Yanagisawa Formation: Kawaguchi Porcelanite Member

Zyumonzi Formation: Shimotomai Volcaniclastic Rock Member; Metoki Coquina Conglomerate Member; Hinosawa Conglomerate Member

Ainoyama Formation

Yabitsu formation

Masuzawa Formation

Yamatsuda Formation

Koshitomaezawa Formation

Ryukawa Formation

Kunimitoge Formation

Obonai Formation

Shimokurosawa Formation: Junijin sandstone member; Tsukumo sandstone member

Osuke formation

Jikyozan andesite

Kumazawagawa Formation

Miocene-Pliocene

Toya Formation: Karumai Pyroclastic Flow Deposit; Asakusazawa Pyroclastic Flow Deposit; Furuyashiki Pyroclastic Flow Deposit

Kubo Formation: Kamazawa Tuff Member

Minamishirasawa Formation

Pliocene (5.33-2.58 Ma)

Kitakamigawa group

Togawa formation

Odaira Formation

Yushima formation

Motohata Formation

Ariga formation

Kazawa formation

Mataki Formation

Kitamatagawa Formation

Kakkondagawa Pyroclastic Rocks

Tamasato Formation

Pliocene-Pleistocene

Kunimiyama Andesite

Quaternary

Yukiura pumice bed

Kawaguchi pumice bed

Nanashigureyama volcano

Takizawa formation

Pleistocene (2.58- 0.01Ma)

Tamagawa Welded Tuff

Shibutami Tuff Bed

Hanaizumi formation

Takakura volcano

Takakurasan Lava Series: Takakurasan 17 Lava; Takakurasan 16 Lava; Takakurasan 15 Lava; Takakurasan 14 Lava; Takakurasan 13 Lava; Takakurasan 12 Lava; Takakurasan 11 Lava; Takakurasan 10 Lava; Takakurasan 9 Lava; Takakurasan 8 Lava; Takakurasan 7 Lava; Takakurasan 6 Lava; Takakurasan 5 Lava; Takakurasan 4 Lava; Takakurasan 3 Lava; Takakurasan 2 Lava; Takakurasan 1 Lava

Takinosawa Lava Series: Takinosawa 13 Lava; Takinosawa 12 Lava; Takinosawa 11 Lava; Takinosawa 10 Lava; Takinosawa 9 Lava; Takinosawa 8 Lava; Takinosawa 7 Lava; Takinosawa 6 Lava; Takinosawa 5 Lava; Takinosawa 4 Lava; Takinosawa 3 Lava; Takinosawa 2 Lava; Takinosawa 1 Lava

Hayawatari Terrace Deposit

Mukokawara Terrace Deposit

Esashika Terrace Deposit

Kusagi Terrace Deposit

Asanai Terrace Deposit

Nanashigure Volcanic Fan Deposit

Towada Kasutera Tephra

Towada Aosuji Tephra

Towada T-17 Tephra

Towada QP Tephra

Towada Hachinohe Fall Tephra

Towada Nanbu Tephra

Takadate Tephra Group

Matsukawa Andesite

Kayodake volcano

Post-caldera lava: Central Cone Lava

Parasitic cone: Eboshidake Lava; Yasumori Lava

Pre-caldera stratovolcano: Maego Lava; Okuro Lava; Akazawa Lava

Kojiromoriyama Volcanic Products

Nyutosan Volcanic Products

Zarumoriyama Volcanic Products

Yumoriyama Volcanic Products

Sankakuyamakita Stratovolcano Products

Sankakuyama Lava Dome

Taigakurayama Volcanic Products

Takakurayama Volcanic Products

Yakeishidake volcano

Kurikomayama volcano

Isawagawa Fan Deposit

Umekami Formation

Pleistocene - Holocene

Iwate volcanic group

Iwate volcano

West-Iwate volcano: Okama Lava; Onawashiro Lava; Yakirizawa Lava; Ubakura Lava

East-Iwate volcano: Hirakasa Debris Avalanche Deposit; Ippongihara Debris Avalanche Deposit

Komatsukuramori Lava

Arinezawa Lava

Koiwai Mudflow Deposit

Yakehashiri lava

Matsuo debris flow deposit

Ubayashiki debris flow deposit

Shizukuishi debris flow deposit

Gohyakumori pyroclastic flow deposit

Matsukawa lahar deposit

Oishiwatari debris flow deposit

Aoyamacho lahr deposit

Marumori volcano: Futatsumori Lava; Marumori Lava Dome; Kamikura Lava

Omatsukura volcano: Omatsukura Lava; Lower Omatsukura Lava; 1162.3m-yama Lava

Inukura volcano: Inukura Debris Flow Deposit; Inukura Lava

Wakare Roam Formation

W1 Unit: Iwate-Kariya Scoria; Iw-ph1 Tephra

W2 Unit

W2a Unit: Iwate-Okawakaitaku Tephra; Iw-ph2 Tephra

W2b Unit: Iwate-Shirishida Scoria

W3 Unit: To-a Tephra

W4 Unit

W4a Unit: AK-1 Tephra; Iwate-Fudotai Tephra

W4b Unit: Iwate-Oide Scoria; Iw-ph3 Tephra; Iw-ph4 Tephra

W5 Unit: Iw-W5 Tephra

W6 Unit

W6a Unit: Iw-W6a Tephra; Iw-ph5 Tephra

W6b Unit: Iw-W6b Tephra

W6c Unit: Iw-W6c Tephra; Iw-ph6 Tephra

W6d Unit: Iw-W6d Tephra

W6e Unit: Iw-ph7 Tephra

W7 Unit

W7a Unit: Iw-W7a Tephra

W7b Unit: Iwate-Suko Scoria; Iw-ph8 Tephra

W8 Unit

W8a Unit: Iw-W8a Tephra; Iw-ph9 Tephra; Iw-ph10 Tephra; Yunosawa pyroclastic deposit

W8b Unit: Iw-W8b Tephra; Iw-ph11 Tephra

W9 Unit: Iw-W9 Tephra; Iw-ph12 Tephra

Ippongi Lapilli Member

Yanagisawa Pumice Deposit

Koiwai Pumice Deposit: K1P; K2P; K3P

Horikiri Pumice Deposit

Mitsuishisan Volcanic Products

Ibonai Terrace Deposit

Rendaino Terrace Deposit

Oritumedake Fan Deposit

Horino Terrace Deposit

Maisawa Terrace Deposit

Hachimantai volcanic group

Obukadake volcano: Obukadake Lava; Kensomori Lava; 1,384m-yama Lava; Yasemori Lava

Chausudake volcano: Maemoriyama Lava; Iwahatayama Lava; Chausudake Lava; Onagane Lava; Oyachi Lava; Daikokumori Agglomerate; Marumori Tuff; Lower Onagane Lava; Ishiyama Lava; Kamotayamagairinzan Lava

Hachimantai volcano: Appidakechienosawa Lava; Gentamori Lava; Appidake Lava; Hachimantai Lava; Mokkodake Lava; Hachimantai-Nishikabu Lava; Kuragata Lava; Yudamatagawa Lava; Komonomori Agglomerate

Holocene (0.01-0 Ma)

Hayasaka Pumice Deposit

Akka Volcanic Ash

Age unknown

Tsubonosawa metamorphic rocks (Tsubonosawa gneiss

Geological structures

Hayachine tectonic belt