京都府南部,田辺丘陵の大阪層群

抄録

The detailed tephrostratigraphical study in the Tanabe Hills revealed the following facts. 1) The Plio-Pliestocene Osaka Group in the Tanabe Hills attains more than 200 m thick and is composed of unconsolidated gravel, sand, silt and clay of limnic, fluvial and marine origin. The succession of these sediments is divided into 4 members, namely the Higashibata alternations, Mizudori gravels, Zakuro alternations and Inuidani alternations, in the ascending order. Among more than 12 volcanic ash layers found in these members, 3 are available as key beds. They are named the Higashibata, Fugenji and Zakuro volcanic ash layers (Fig. 2, 3 and 5). 2) On the basis of the tephrostratigraphic and petrographic data of volcanic ash layers, the Higashibata and Zakuro volcanic ash layers can be correlated with the Fukuda and Pink volcanic ash lavers in the southern part of Osaka (Fig. 8).