更新世谷下石灰岩裂罅堆積物(静岡県引佐町)の脊椎動物化石
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概要
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The small-scale limestone masses are sporadically distributed in the north to the Hamana Lake, Shizuoka Prefecture. Abundant fossils of Pleistocene vertebrates have so far been excavated from fissure deposits of these limestones. The Pleistocene vertebrate faunas of the "Yage" Limestone Fissure Deposits at Inasa-cho, Inasa-gun are one of the most important Japanese Quaternary vertebrate faunas to make clear relation between the faunas in the Japanese Islands and the Asian Continent during the Quaternary. The "Yage" Lime-stone Fissure Deposits, the Yage Formation, is divided into the lower part (fresh water sedi-ments) and the upper part (terrestrial sediments). The lower part (ca. 6.5 m in thickness) consists of laminated red to yellowish brown clay, and intercalates five fossil fish bone layers (F3=50〜80cm, F2=15〜25cm, Fl=2cm, F02=8cm, F01=2cm in thickness, respectively) and a volcanic ash layer (approximately 1 m in thickness). From these fish bone layers, four species of fresh-water fishes, Carassius sp., Cyprinus carpio, Distoechodon sp., Parasilurus sp. Were identified, and from the uppermost part of the F3 fish bone layer, eight hundred bones of crocodylids were excavated with a ventral plastron of Ocadia sinensis and a humerus of Lutra sp. The lower part is correlated to the Sahama Formation on the basis of the level of sedimentary surface, volcanic ash, and sedimentary environment. The geological age of the lower part is assignable to the Mindel-Riss Interglacial age. The upper part (3〜8m in thickness) is composed of the yellowish brown clay containing subangular lime-stone and chert gravels. The following fossil vertebrate bones over a thousand in number were excavated from residual clay and travertine into the fissure deposits of the upper part : the eight extinct species (Canis lupus, Meles meres anakuma, Putorius kuzuuensis, Nipponicervus praenipponicus, Sinomegaceros yabei, Palaeoloxodon naumanni, Anourosorex japonicus, and Panthera tigris) and living 18 species including Microtus montebelli, Nyctereutes viverrinus, and Rhinolophus ferrumequinum. Based on the fossil vertebrate species, this upper part is correlated to the upper Kuzuu Formation, Tochigi Prefecture and the upper Isa Formation, Yamaguchi Prefecture. The geological age of this part is assignable to the Wurm glacial age.
- 静岡大学の論文