[ Top ] [ Japanese ]

Isumi 1 (Yoshifu) Terrace Deposits (Kuwahara et al., 2000) Utsunomiya and Ooi, 2019

Invalid synonym: Yoshifu Terrace Deposit, Isumi 1 Terrace Deposit

• Coherent formation
• Pleistocene (33,500, 33,290 yBP, ¹⁴C; MIS 3)
• Contemporaneous heterotopic facies: Isumi 1 Terrace Deposits

• Sedimentary facies: Coastal terrace deposit, River terrace deposit
• Sedimentary facies: Canyon fill deposit
• Sedimentary facies (Upper): Marine
• Sedimentary facies (Upper): Ravinement surface, Lagoon, Marsh
• Climate: Cold temperate
• Lithofacies (Upper): Sands, Mud
• Lithofacies (Lower): Mud
• Lithofacies (Lower, Minor): Peat
• Sedimentary structures (Upper): Wedge-shaped cross-stratification, Parallel stratification

• Thickness: 10 m or thinner
• Thickness (Upper): 5.6 m
• Thickness (Lower): 4.3 m or thicker
• Upper limit: Unconformity (Tachikawa Loam)
• Lower limit: Unconformity (Kazusa Group)

• Distribution: Ichigaya - Kotaki - Taito - Hikida - Takatanidai, Isumi city, Chiba pref.; Yagami - Nakahara, Misaki town, Isumi city, Chiba pref.; Tsunada, Ichinomiya city, Chosei county, Chiba pref.; Shimootaki, Otaki city, Isumi county, Chiba pref.; Haga, Katsuura city, Chiba pref.
• Fossils (Pollen): Abies sp., Cryptomeria sp., Fagus sp., Picea sp., Pinus sp., Quercus sp., Tsuga sp.
• Fossils (Trace fossils): Macaronichnus segregatis
• Tephra: AT

• Utsunomiya and Ooi (2019) Geology of the Kazusa-Ohara District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 127p. (in Japanese with English abstract 4p.)
• 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.)