The Journal of the Geological Society of Japan
Online ISSN : 1349-9963
Print ISSN : 0016-7630
ISSN-L : 0016-7630
Volume 55, Issue 642-643
Displaying 1-3 of 3 articles from this issue
  • Jitsutaro TAKUBO, Mitsue SAITO
    1949 Volume 55 Issue 642-643 Pages 33-37
    Published: August 20, 1949
    Released on J-STAGE: April 11, 2008
    JOURNAL FREE ACCESS
    Allanite is found in pegmatite or aplite dikes widely distributed in Angaku Mine field., Field ohservations indicate that the mineral is genetically related with granite gneiss which was intruded or caught up as xenolith by two-mica granite., The latter granite probably brought up allanites., The physical and chemical properties of allanite from Angaku were investigated., X-ray spectroanalysis was undertaken to determine the content of rare earth elements and it was shown that the content of each element was in following order, approximately agreeing with Harkins' Law : 58Ce, 57La, 60Nd, 59Pr, 62Sm, 64Gd, 63Eu., It is noticable that the water content in this allanite is notably small, so the allanite now in question can be called bucklandite., The chemical composition was determined from the analytical results and it was shown that the mineral belonged to the orthosilicate group.,
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  • Ryohei MORIMOTO
    1949 Volume 55 Issue 642-643 Pages 38-43
    Published: August 20, 1949
    Released on J-STAGE: April 11, 2008
    JOURNAL FREE ACCESS
    During his petrological study on the inclusions in the garnet-biotite-andesite from Nijo Volcano near Osaka, the present writer pointed out the common occurrence of spinel associating intimately with porphyroblastic andalusite or sillimanite in some xenoliths derived from argillaceous metamorphic rock, as the feature to be observed in xenoliths when they had been enclosed in a volcanic magma., This spinel is not found in the xenoliths slightly or completely metamorphosed by the enclosing magma, but in the ones metamorphosed to a moderate degree., It is conceivable that spinel is formed in xenoliths in an intermediate stage of metamorphism owing to an attacking magma, and disappears when the mutual reaction between the xenolith and magma is more advanced., This consideration coincides with the common occurrence of spinel from xenoliths in effusive or hypabyssal rocks but not from xenoliths in plutonic rocks.,
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  • Katsuhiko SAKAKURA
    1949 Volume 55 Issue 642-643 Pages 44-48
    Published: August 20, 1949
    Released on J-STAGE: April 11, 2008
    JOURNAL FREE ACCESS
    Paleontologists working in Tertiary oil fields are using smaller forminifera as effective tools in correlation of strata., It seems, however, only one face of fauna, i., e., qualitative face, is being considered in the form of range chart, or distribution chart, which may be called "a qualitative analysis., " The author expressed the necessity of another face of fauna, that is "quantitative" in character., The quantitative analysis means a statistic analysis of fauna which is a new branch of Paleosynecology., Foraminiferal fauna to be stndied by this method should be treated statistically, and after numbering individuals and species of foraminifera, paleosynecological considerations will be done to assemblages., The author discussed in this paper, 1) Necessity of statistical method in applied paleontology of oil field, 2) Sampling method, and 3) Method of statistical studies in general.,
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