The Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists
Online ISSN : 1883-0765
Print ISSN : 0021-4825
ISSN-L : 0021-4825
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Volume 55, Issue 6
Displaying 1-4 of 4 articles from this issue
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  • Clay minerals of volcanic ash in japan
    volcanic ash soils in the northeastern part of Japan
    Jun-ichi Masui
    1966 Volume 55 Issue 6 Pages 221-241
    Published: June 05, 1966
    Released on J-STAGE: August 07, 2008
    DOIhttps://doi.org/10.2465/ganko1941.55.221
    JOURNAL FREE ACCESS
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    Soils formed from volcanic ash distributed by several volcanos in the northeastern part of Japan have been studied by means of X-ray diffraction, infrared spectroscopy, differential thermal analysis and chemical analysis.
    The content of amorphous materials of the clay less than one micron is about seventy five per cent in the early stage os weathering, and is about forty per cent in the advanced. The essential minerals of the soils in every stage of weathering are 14A clay minerals. The kaolin minerals are found in small amounts.
    The weathering sequence of the volcanic ash soils in this district based on the mineralogy appears to be as follows: Volcanic ash soil - allophane - montmorillonite - vermiculite-Al chlorite intergrade
    The small amounts of halloysite, Al-chlorite and illite are found in every stage.
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  • STUDIES ON THE PYRRHOTITE GROUP MINERALS (I)
    -DRY SYNTHESIS OF MONOCLINIC PYRRHOTITE-
    ASAHIKO SUGAKI, HIROMI SHIMA
    1966 Volume 55 Issue 6 Pages 242-253
    Published: June 05, 1966
    Released on J-STAGE: August 07, 2008
    DOIhttps://doi.org/10.2465/ganko1941.55.242
    JOURNAL FREE ACCESS
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    Though the genetic mechanism of monoclinic pyrrhotite in natural occurrence and its phase equilibrium relations with hexagonal pyrrhotite have not been accurately known yet, two mechanisms of the formation through the inversion from hexagonal pyrrhotite with a descending temperature and of the direct formation as monoclinic pyrrhotite at a low temperature below 320°C from ore solution are supposed. In order to examine the possibility of the former mechanism, monoclinic pyrrhotite was synthesized by means of annealing hexagonal pyrrhotites with various compositions. When synthesized hexagonal pyrrhotites with the seven compositions between 47.39 and 46.08 atomic percent Fe were annealed at 290°C or 300°C for 48 or 96 hours, they were not changed in the composition of 47.39 and 47.17 atomic percent Fe, but monoclinic pyrrhotite was formed by the inversion from hexagonal pyrrhotite in the compositions from 46.95 to 46.08 atomic percent Fe. In the sulfur rich composition such as 46.30 or 46.08 atomic percent Fe, pyrite was found with monoclinic pyrrhotite. On the basis of these data the composition ranges of hexagonal and monoclinic pyrrhotities are discussed.
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  • WAIRAKITE IN JAPAN (I)
    YÔTARÔ SEKI
    1966 Volume 55 Issue 6 Pages 254-261
    Published: June 05, 1966
    Released on J-STAGE: August 07, 2008
    DOIhttps://doi.org/10.2465/ganko1941.55.254
    JOURNAL FREE ACCESS
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  • A singular silica sublimate mineral found in Satuma-Iwo-zima Volcano (II)
    Minoru Yoshida, Takejiro Ozawa, Joyo Osska
    1966 Volume 55 Issue 6 Pages 262-271
    Published: June 05, 1966
    Released on J-STAGE: August 07, 2008
    DOIhttps://doi.org/10.2465/ganko1941.55.262
    JOURNAL FREE ACCESS
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