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Yumigahama Formation

Invalid name: Yumigahama Sand Bar

Marine clay bed at the lower level than Nakaumi Formation

There are opinions that the mud-sands-gravels bed covered with Daikonjima Basalt and Eshima Basalt is not Yumigahama Formation.

• Coherent formation
• Pleistocene

• Sedimentary facies: Marine
• Sedimentary facies: Sand bars, Beach ridges, Interbarnal lowlands
• Lithofacies: Sands, Gravels, Clay

• Thickness: 12 - 17 m
• Upper limit: Unconformity (Daikonjima Basalt?, Eshima Basalt?, Yasugi Formation?)

• Distribution: Daikon island - Eshima island, Yatsuka village, Matsue city, Shimane pref.
• Fossils (Shellfishes): Anadara broughtonii, Anadara granosa, Cerithidea djadjariensis, Dosinia penicillata, Nassarius eivescens, Paphia undulata, Theora lubrica?, Tritia festiva

• Sawada et al. (2009) Jour. Geol. Soc. Japan, vol.115, Supplement, pp.51-70 DOI
• Kano et al. (1998) Geology of the Taisha District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 58p. (in Japanese with English abstract 3p.)
• Kano and Nakano (1985) Geology of the Mihonoseki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 28p. (in Japanese with English abstract 3p.)
• Kano and Yoshida (1985) Geology of the Sakaiminato District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 57p. (in Japanese with English abstract 5p.)