著者

柏崎ナウマンゾウ研究会

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.45, no.3, pp.161-176, 1991

被引用文献数

1

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Palaeoloxodon naumanni (Makiyama) was found in the Upper Pleistocene Yasuda Formation at Kashiwazaki City, Niigata Prefecture, in the Japan Sea borderland. Juding from the fact it forms widely developed terraces and contains temperate-wet macroscopic plant remains, and from the thermoluminescence dating (Hashimoto and Habuki, 1989), the Yasuda Formation is considered to be the deposits of the last interglacial age. This fossil Naumann's elephant was described and several fossil remains were analyzed. In this paper, some morphological features of this Naumann's elephant and his life palaeoenvironment at a local area in the last interglacial age were discussed. 1) A pair of tusk and a pair of upper first molar were separately detected in two horizons of the Yasuda Formation. The individual with tusk is a possiblly mature male elephant of which hight of shoulder is over 2.5m, and one with molar is a possiblly mature elephant 15〜18 years old of which hight of shoulder is 1.5m〜2m. 2) From the distribution of the Yasuda Formation, these individuals seem to have been buried in the deepest area of valley. 3) The Yasuda Formation around this area was mainly deposited under fresh water conditions with a little effect of marine water. Unio douglasiana, Trapa incisa and T. macropoda flourished in this stagnant pool. 4) Predacious ground bettle (ex. Carabas insulicola) and Coprophagous bettle (Copris tripartitus) inhabited, and Styrax obbassia, Stewartia pseudo-camellia flourished in the hills or on the shore where Naumann's elephants were living. Fagus crenata and Quercus sp. flourished in the mountainous area. 5) The climate when Naumann's elephants were living, is considered to have been nearly same as that around present Kashiawazaki City, from fossil bettle, macroscopic plant remians and fossil pollen assemblages. 6) The absence of distinct marine fossils suggests the existence of some barieer disturbed the entrance of marine waters in present Japan Sea area.