著者

中山 勝博 河村 善也

出版者

地学団体研究会

雑誌

地球科學 (ISSN:03666611)

巻号頁・発行日

vol.47, no.4, pp.289-300, 1993-07-25

被引用文献数

1

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The Plio-Pleistocene Osaka Group in the Nara Hills is composed mainly of fluvio-lacustrine sediments with 15 intercalations of volcanic ash. Of these volcanic ash layers, nine principal layers are described in detail on the basis of lithology and analyses of mineral assemblage and of glass shape and refractive index. The results of the observation and analyses indicate that four of them such as the Pumice-sand, Shimoumedani, Kurokamiyama II, and Takanohara volcanic ash layers are correlative with the Higashibata, Fugenji, Susudani I, and Zakuro volcanic ash layers in the adjacent Tanabe Hills respectively. Further, the Shimoumedani, Kurokamiyama II, and Takanohara volcanic ash layers are correlated with the Fukuda, Yellow IV, and Pink volcanic ash layers in the SennanSenpoku Hills respectively, where one of the stratotypes of the Osaka Group is exposed. The correlation indicates that the Osaka Group in the Nara Hills is assignable to the lower-most and lower parts of the standard sequence of the group.