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 58, Issue 5
Displaying 1-4 of 4 articles from this issue
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  • Transformation of talc, chlorite and muscovite by an electron bombardment
    Mizuhiko Akizuki
    1967 Volume 58 Issue 5 Pages 161-169
    Published: November 05, 1967
    Released on J-STAGE: August 07, 2008
    DOIhttps://doi.org/10.2465/ganko1941.58.161
    JOURNAL FREE ACCESS
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    In order to study the crystallographic relationship between parent (talc, chlorite and muscovite) and product structure, the transformation was carried out in stages within an electron microscope by condensing the electron beam. The process was monitored by electron diffraction.
    In another experiment, these materials were heated slowly and rapidly in an external vacuum furnace. The results of the electron bombardment experiment and the heating experiment were then compared.
    The enstatite obtained by electron bombardment of talc shows similar diffraction diagram with that obtained by slow heating of talc. On the other hand, the diagram differs markedly from that obtained by rapid heating of talc. The olivine crystal formed from chlorite by electron bomharmdent is larger than that formed from the same material by heating far 4 hours at 1000°C.
    These results suggest that the transformation obtained by electron bombardment in the electron microscope are essentially due to ionization rather than heating.
    This technique must be highly applicable to the identification of some clay minerals.
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  • REEXAMINATION OF THE CRYSTAL STRUCTURE OF MONAZITE
    TATEO UEDA
    1967 Volume 58 Issue 5 Pages 170-179
    Published: November 05, 1967
    Released on J-STAGE: August 07, 2008
    DOIhttps://doi.org/10.2465/ganko1941.58.170
    JOURNAL FREE ACCESS
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    Crystal structure of monazite has been reexamined whether the nine O atoms around Ce atom are in a regular fashion as is the case in Ce(OH)3 and CeCl3. The structure reexamined is almost the same as that reported by the author in 1953 and is fundamentally the same as that proposed by Mooney (1948).
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  • Petrology of Neogene Tertiary basic volcanic rocks of northeastern Japan
    1. Mitaki tholeiite series
    Ken-ichiro Aoki
    1967 Volume 58 Issue 5 Pages 180-187
    Published: November 05, 1967
    Released on J-STAGE: August 07, 2008
    DOIhttps://doi.org/10.2465/ganko1941.58.180
    JOURNAL FREE ACCESS
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    The Mitaki tholeiite series of Sendai which consists of late Miocene tholeiite and tholeiitic andesite occurs as lava flows ranging from 5 to 30min thickness and as dyke swarms ranging from O.5 to 5.7 min width. Petrographically, the series is characterized by abundance of large anorthite phenocryst which reaches up to 35 per cent by volume. The groundmass is composed of labradorite, cristobalite, pigeonite, augite, and iron ore. The tholeiite is distinguished from the tholeiitic andesite by the following characteristics: (1) smaller amount of interstitial cristobalite, and (2) higher pigeonite/augite ratio. Six rock samples have been analyzed chemically. Those having the chemical composition of typical tholeiite series are notably rich in total iron and CaO and very poor in alkalis. This shows strong iron enrichment at the middle stage of fractionation.
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  • Studies on the brine water of the Kujukuri gas field
    Especially on the destribution of halogens
    Taiji Isomura
    1967 Volume 58 Issue 5 Pages 188-200
    Published: November 05, 1967
    Released on J-STAGE: August 07, 2008
    DOIhttps://doi.org/10.2465/ganko1941.58.188
    JOURNAL FREE ACCESS
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    The chemical analyses of seventy-eight samples of brine water in the Kujukuri gas field were carried out, and compared formationally and regionally.
    At Mohara and Otaki districts, the ratios of I-/Cl- and Br-/Cl- are higher in the water of the lower Otadai and the Kiwada formations, than those of the overlying Umegase, and the underlying Ohara, Namihana and Katsuura formations. Regionally these ratios of the waters of the Kiwada formation decrease in the direction to the North. This fact reveals the coincidence with the tendency of thinning out of the formation to the same direction.
    If we assume that dI -and dBr- are the enriched portion of I- and Br- in the brine water after the deposition of sediments, the ratio of dI-/dBr- remains nearly constant as 1.5_??_1.9 in this field. This fact suggests that the sources of I- and Br- are derived from the same materials, which may be the algae having high concentrations of the iodine and the bromine.
    The high values of I-/Cl- and Br-/Cl-in the water of the muddy “Kiwada” formation compared to those of the sandy ones (“Umegase”, “Ohara”, etc.) also show that there were enrichment of the organic matters to the Kiwada formation at the time of deposition.
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