| 概要 |
The second report on the Ideyama Formation in the Chikuho Coal: field deals with the lithology, stratigraphy and geological structure of the formation in the Nogata district. The problems on the upper...- and lower-limits of this formation, and the relationship to the underlying Tertiary formations are also discussed in this paper. Owing to the. wide distribution of the overlying Quaternary deposits such as alluvium and diluvium (terrace deposits), the Ideyama Formation in this district crops out not so well as in the Tagawa district, nevertheless the same succession of strata can be traced continuously. The Ideyama Formation of the Nogata district is divided by means of the cycle of sedimentation into: five members, A to E in ascending order. They are correlated to the A to E members of the Ideyama Formation in the Tagawa district. The Ideyama Formation in this district, which is composed predominantly of coarsegrained deposits, shows nearly a similar stratigraphy with that in the Tagawa district. Strictly speaking, however, the lithology of the upper three members, C, D and E, changes from the: fine-grained facies in the Tagawa district to coarse-grained facies without carbonaceous matters in this area. The upper three members also show nearly the same tendency of thinning out northward. In some areas, such as in Onizu and Kojaku-Kamitonno, where are far from the main distribution area of the Ideyama Formation, the formation is hardly differentiated due to isolated and limited outcrops. The geological structure of the Tertiary in this district is a typical "Chikuho-type" structure, and the synclinal axis of folding, being parallel to the Fukuchiyama fault, leans to northward.続きを見る
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Mendeley出力
