Sedimentary Environments of the Main Part of the Kumano Group : A Study of the Tertirary Formations of the Kumano Coal-field in the Kii Peninsula, Southwest Japan, Part 2

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The main part of the Kumano Group is characterized by a rhythmic succession of the sediments which accumulated in offshore marine, marginal marine and barrier island environments. The offshore facies consists of generally massive and poorly sorted sandy siltstone and mudstone, and yields marine benthic fossils. The transition from the offshore facies to the marginal marine facies is represented by gradual increase of well-bedded sandstones which become thicker and coarser-grained upwards, and exhibit small-scale cross-bedding. Father up in the section, corresponding to the barrier island facies, sediments are composed mainly of very thick-bedded, medium- to coarse-grained sandstones which commonly show cross- and plane-lamination. In the section from the alternating beds to the lower part of this unit many burrows including Ophiomorpha are commonly found, and in the upper part of thick sandstone unit, thin coal seams that were produced in coastal swamps are intercalated. The change from the barrier island facies to the succeeding marine mudstone facies is generally rather abrupt. The cyclic succession of lithofacies recognized in the Kumano Group is considered to have been produced by periodic progradation and retrogradation of the strands.

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Details 詳細情報について

  • CRID
    1390290699732309504
  • NII Article ID
    120006876058
  • NII Book ID
    AA00732897
  • DOI
    10.5109/1546081
  • HANDLE
    2324/1546081
  • ISSN
    00236179
  • Text Lang
    en
  • Article Type
    departmental bulletin paper
  • Data Source
    • JaLC
    • IRDB
    • Crossref
    • CiNii Articles
    • OpenAIRE
  • Abstract License Flag
    Allowed

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