Shirakawaike Formation

Shirakawaike Formation Makiyama, 1931

Type locality: Shirakawa dam, Nara city, Nara prefecture
Coherent formation
Pleistocene
Correlation: Mizutori Member, Zakuro Member

Sedimentary facies: Fluvial
Lithofacies: Gravels, Sands, Silt
Lithofacies (Minor): Volcnic ash
Sedimentary structures: Graded bedding, Channel structure, Cross stratification

Thickness: 100 m or thicker
Upper limit: Unconformity (Kokuzoyama Conglomerate Member, Terrace deposits)
Lower limit: Unconformity (Fujiwara Group, Jigokudani Formation)

Osaka Group (Nara, Nara pref.)
[ Upper ]
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Kokuzoyama Conglomerate Member
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Shirakawaike Formation
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[ Lower ]

Second Setouchi Supergroup (Osaka pref. - Hyogo pref.)
[ Upper ]
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Osaka Group
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[ Lower ]

[ Upper ]
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Second Setouchi Supergroup
?--?--?--?--?-
First Setouchi Supergroup
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[ Lower ]

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

Distribution: Shirakawa dam - Rokuyaon town - Fujiwara town - Kubonosho town, Nara city, Nara pref.; Wani town - Toyoda town - Somanouchi town, Tenri city, Nara pref.
Fossils: Wood fragments
Fossils (Plants): Juglans megacinerea, Juglans sieboldiana, Metasequoia sp.
Fossils (Pollen): Abies sp., Acer sp., Aesculus sp., cf. Alchornea sp., Alisma sp., Alnus sp., Artemisia sp., Betula sp., Carduoideae, Carpinus-Ostrya, Caryophyllaceae, Cichorioideae, Cornus sp., Corylus sp., Cryptomeria sp., Cyperaceae, Fagus sp., Fraxinus sp., Gramineae, Hamamelis sp., Impatiens, Juglans sp., Ligustrum sp., Liquidambar sp., Lycopodium sp., Metasequoia sp., Osmunda sp., Parthenocissus sp., Picea sp., Pinus (Diploxylon) sp., Pinus (Haploxylon) sp., Polygonum, Pseudotsuga sp., Quercus (Lepidobalanus) sp., Ranunculaceae, Rosaceae, Salix sp., Sapium sp., Sciadopitys sp., Sparganium sp., Styrax sp., Taxaceae-Cephalotaxaceae-Cupressaceae, Thalictrum sp., Tilia sp., Tsuga sp., Ulmus-Zelkova, Viscum sp.

Nishioka et al. (2001) Geology of the Sakurai District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 141p. (in Japanese with English abstract 5p.)