[ Top ] [ Japanese ]

Kassenba Formation Sugimoto, 1974

Some researchers proposed to be included in Otori Unit.

• Type locality: Kassenba, Shimohata, Yamagata town, Kuji city, Iwate prefecture
• Accretionary complex
• Deposition (Chert): Middle - Late Triassic (Conodont)
• Deposition (Siliceous mudstone): Middle Jurassic, Bajocian - Late Jurassic, Oxfordian (Radiolarians)
• Deposition (Mudstone): Middle Jurassic, Aalenian? - Late Jurassic, Kimmeridgian (Radiolarians)
• Accretion: Oxfordian - Kimmeridgian, Late Jurassic (Radiolarians)

• Sedimentary facies: Marine
• Lithofacies: Coherent facies (2 Chert-clastic sequences)
• Lithofacies (Upper): Sandstone
• Lithofacies (Middle): Siliceous mudstone, Mudstone
• Lithofacies (Lower): Chert

• Thickness: 2,000 m or thicker
• Thickness (Upper): 500 - 1,000 m or thicker
• Thickness (Lower): 200 - 300 m
• Upper: Oritsume thrust fault (Kuzumaki Formation), Unconformity (Mukokawara Terrace Deposit, Hayawatari Terrace Deposit)
• Lower limit: Takinosawa-Yomogigamori thrust fault (Seki Formation)

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

• Distribution: Kassenba, Shimohata, Yamagata town, Kuji city, Iwate pref.; Hareyama - Sannai, Karumai city, Kunohe county, Iwate pref.; Esashika - Chokoji - Ibonai, Kunohe city, Kunohe county, Iwate pref.; Nikarube, Yamagata town, Kuji city, Iwate pref.
• Fossils: Radiolarians
• Fossils (Conodonts): Epigondolella bidentata

• Tuzino et al. (2018) Geology of the Ichinohe District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 161p. (in Japanese with English abstract 4p.)
• Yoshida et al. (1987) Geology of the Rikuchu-Ono District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 70p. (in Japanese with English abstract 6p.)