[ Top ] [ Japanese ]

Joso Formation (Nakamura and Fukuda, 1953)

• Coherent formation
• Paleo-Tokyo bay fill deposit
• Pleistocene (MIS 5.3)
• Contemporaneous heterotopic facies: Shimosueyoshi Loam
• Correlation (Upper): Ibaraki Clay Formation

• Sedimentary facies: Marine, Brackish-Fluvial
• Sedimentary facies: River mouth of tidal river
• Sedimentary facies (Lower): River channel deposit
• Sedimentary facies (East): Flood plain
• Sedimentary facies (Sands): River-side sand dunes
• Lithofacies (Marine): Sandstone
• Lithofacies (Brackish-Fluvial): Tuffaceous clay bed, Interbedded sandstone and mudstone, Sandy conglomerate
• Lithofacies (East): Mud
• Lithofacies (West): Tuffaceous clay bed, Mud, Sands
• Lithofacies (Minor): Peat
• Sedimentary structures: Upward fining
• Sedimentary structures (Sandy conglomerate): Trough cross-stratification

• Thickness: ca. 1 - 20 m
• Thickness (Joso Clay): A few dozen cm - 2 m
• Thickness (Lower): 10 - 20 m
• Upper limit: Bottom of Musashino Loam
• Upper limit: Unconformity (Ichihara I Terrace Deposits)
• Lower limit: around the horizon of On-Pm1
• Lower limit: Interfengered (Omiya Formation), Conformity or Unconformity (Kioroshi Formation), Unconformity (Kiyokawa Formation, Yokota Formation, Jizodo Formation, Yabu Formation, Kamiizumi Formation)

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

• Distribution: Hitachi terraces - Tsukuba terraces, Ibaraki pref.; Anegasaki area, Chiba pref.
• Distribution: Kongochi, Ichihara city, Chiba pref.; Ryugasaki city, Chiba pref.; Ishitoshuku, Kitamoto city, Saitama pref.; Haramamuro, Konosu city, Saitama pref.; Takamushi, Hasuda city, Saitama pref.; Chayashinden - Makinoji, Koga city, Ibaraki pref.
• Fossils: Plant roots
• Fossils (Pollen): Cryptomeria sp., Picea sp., Tsuga sp.

Tephra: On-Pm1, SIP, An1, An2, Hk-KlP

• Sakata et al. (2018) Jour. Geol. Soc. Japan, vol.124, no.5, pp.331-346 DOI
• Nanayama et al. (2016) Geology of the Mobara District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 101p. (in Japanese with English abstract 4p.)
• Naya and Yasuhara (2014) Geology of the Konosu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 82p. (in Japanese with English abstract 3p.)
• Ooi et al. (2013) Jour. Geol. Soc. Japan, vol.119, no.7, pp.488-505 DOI
• Ooi and Yokoyama (2011) Jour. Geol. Soc. Japan, vol.117, Supplement, pp.103-120 DOI
• Nakazawa and Tanabe (2011) Geology of the Noda District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 72p. (in Japanese with English abstract 3p.)
• Nakazawa et al. (2009) Jour. Geol. Soc. Japan, vol.115, no.2, pp.49-63 DOI
• Komatsubara et al. (2004) Geology of the Kisarazu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 64p. (in Japanese with English abstract 3p.)
• Nakazawa and Endo (2002) Geology of the Omiya District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 41p. (in Japanese with English abstract 3p.)
• Miyazaki et al. (1996) Geology of the Makabe District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 103p. (in Japanese with English abstract 4p.)
• Tokuhashi and Endo (1984) Geology of the Anesaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 136p. (in Japanese with English abstract 6p.)