Heavy minerals in the Tsukiyoshi orebody, Tono uranium deposit, central Japan

DOI Web Site 36 References
  • SASAO Eiji
    Geological Isolation Research and Development Directorate, Japan Atomic Energy Agency, 1-64, Yamanouchi, Akeyo-cho, Mizunami-shi, Gifu 509-6132, Japan
  • NAKATA Masataka
    Faculty of Education, Tokyo Gakugei University, 4-1-1 Nukui Kita-machi, Koganei, Tokyo 184-8501, Japan
  • KOMURO Kosei
    Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Ten'nodai, Tsukuba, Ibaraki 305-8572, Japan

Bibliographic Information

Other Title
  • 東濃ウラン鉱床月吉鉱体の重鉱物組成
  • トウノウ ウラン コウショウゲツ キチコウタイ ノ ジュウ コウブツ ソセイ

Search this article

Description

Heavy minerals are examined in uranium ores and the associated rocks of the Tsukiyoshi orebody, Tono sandstone-type uranium deposit, central Japan. The samples used are uranium ores hosted in the Toki Lignite-bearing Formation, sandstones taken from a series of a stratigraphic succession, i.e., Toki Lignite-bearing, Hongo and Akeyo Formations in the Miocene Mizunami Group, in ascending order, and late Cretaceous to Paleogene basement granitic rocks. Amounts of heavy minerals are counted under a microscope for non-magnetic fractions with the specific gravity of >2.85 and the diameter from 0.0625 to 0.125 millimeter.<br>Heavy minerals in the uranium ores are composed mainly of biotite, green hornblende and opaque minerals, with minor clinopyroxene, epidote, zircon and brown hornblende. One ore sample contains topaz, cassiterite, garnet and allanite. Heavy minerals in the non-mineralized sandstone from the Toki Lignite-bearing Formation consist mainly of green hornblende and opaque minerals, with some clinopyroxene and orthopyroxene and minor brown hornblende, apatite, epidote and anatase. The sandstones from Hongo and Akeyo Formations contain clinopyroxene, orthopyroxene and opaque minerals. Heavy minerals in basement granitic rocks are composed mainly of biotite with some opaque mineral, zircon, fluorite, epidote and anatase.<br>On the basis of comparison of heavy mineral composition of rocks around the Tsukiyoshi orebody, three sources of detritus are estimated, i.e., (1) granitic source composed mainly of biotite, zircon and fluorite, (2) volcanic ash source of hornblendes and pyroxenes and (3) pegmatitic and hydrothermal sources of topaz and cassiterite. Uranium ores are proved to be embedded in the detritus mainly of granitic source, whereas the other sandstones in the Mizunami Group are mainly from volcanic source. Topaz and cassiterite in the ores are estimated to be derived from the pegmatitic and hydrothermal deposits with the Naegi granite developed at the northeastern side of the Tsukiyoshi orebody.

Journal

  • Shigen-Chishitsu

    Shigen-Chishitsu 62 (3), 225-233, 2012

    The Society of Resource Geology

References(36)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top