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Volume 60, Issue 708
Displaying 1-4 of 4 articles from this issue
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Kameki KINOSITA, Kunihiko MUTA1954 Volume 60 Issue 708 Pages 363-377
Published: September 25, 1954
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSThe Ebisu iron mine is situated about 7 km., southwest of Mitoya-machi, Shimane Prefecture., The area of the mine is chiefly occupied by quartz diorite, granodiorite and biotite granite., The iron deposits under consideration are found as irregular masses or lenses of magnetite-bearing quartz diorite in the center of a narrow belt of biotite granite., Three types of magnetite are found, (1) idiomorphic magnetite enclosed in other minerals, (2) idiomorphic or hypidiomorphic magnetite filling up the interspaces of quartz and feldspar, and (3) acicular, tabular or xenomorphic magnetite disseminated through rock mass., Of these, the first and the second types are intratelluric, slightly earlier in crystalization stage, than mica, quartz, and feldspar while the last one is later than hedenbergite, garnet, etc., and forms high grade ore., The high grade ore seems to have been formed by secondary pneumatolytic concentration of the early magmatic magnetite.,View full abstractDownload PDF (2182K) -
M. MINATO, S. HASHIMOTO, K. SUYAMA, Y. TAKEDA, Y. SUZUKI, T. KAKIMI, K ...1954 Volume 60 Issue 708 Pages 378-387
Published: September 25, 1954
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSDie machtige permische Formation des Setamai-Gelandes im Kitakami-Gebirge ist in zwei Subsystem teilbar; das obere ist das Toyoma-Untersystem, das lithologisch meistens aus Tonschiefern und granitfuhrenden Konglomeraten besteht und verhaltnismassig fossilarm ist, wahrend dagegen das untere Untersystem, d., i., das Yukisawa-Untersystem, ortlich sehr reich an kalkigen Tonschiefern bzw., Kalkschichten ist und bestehend fossilfuhrend., Hinsichtlich der vielen Gliedrungstiere kann das Yukisawa-Uutersystem wieder in zwei Serien gegliedert werden, in die Sakamotosawa- und Kanokura-Serie., Wir sind dabei der Ansicht, dass eine stratigraphische Lucke zwischen beiden vorhanden ist., Die wichtigsten Ergebniss in Bezug auf die Dauerzeit der Gattungen bzw., Spezies sind folgende: 1., Pseudoschwagerina erscheint bald nach dem Basiskonglomerat der Sakamotosawa-Serie und dauert bis zur J0 Horizonte (Siehe Abb., 2)., 2., Dagegen erscheint Parafusulina in der I2 Horizonte und dauert bis zur L0., 3., Lepidolina zeigt eine Dauerzeit zwischen L0 und L1., 4., Lophophyllidium suetomii MINAT0 sind die wichtigen Gliederungstiere der I0 Horizonte; Yatsengia Kabayamensis MINATO und Michelinia (Michelinopora) multitabulata YABE et HAYASAKA tritt besonders in der Horizonte J1 auf; Waagenophyllum indicum var., usuginuensis MINATO, Wentzelella kitakamiensis YABE et MINATO charakterisieren die Horizonte L0., 5., Die sogenanten Lyttonia-Faunen HAYASAKAS trenten nur im unteren Teile der Kanokura-Serie auf.,View full abstractDownload PDF (1048K) -
Yo NARUSE1954 Volume 60 Issue 708 Pages 388-399
Published: September 25, 1954
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSThe Toyofusa formation in the southernmost part of the BOSO Peninsula is characterized mainly by mixed fossil biocoenoses and variable lithologic facies with tuffaceous sediments and intraformational conglomerates., These were examined genetically in relation to diastrophism and the sedimentary environment of the formation., Conclusions are as follows: 1 The Toyofusa formation accumulated in a part of a geosynclinal trough., Subsidence of the floor continued in the south and compensatory upheaval in the north of this part of the geosyncline during the epoch., 2., Clastic material for the formation was supplied from the north and west of this area., 3., A warm current comparable to the Kuroshio of today, ran near the rocky shore., There was also an under current of low temperature comparable to the present Oyashio under current., 4., Silt and sand rhythmically accumulated on the deep sea floor of the trough., Occasionally shell-bearing tuffaceous coarse sands with siltstone blocks of various sizes slid down the slope and were intercalated in the above-mentioned alternation., 5., These conditions and mode of sedimentation continued during almost the whole period of accumulation of the formation., 6., The sea in which the Toyofusa formation was deposited finally disappeared during the Plio-Pleistocene tectonic activity of the Tanzawa orogensis.,View full abstractDownload PDF (1464K) -
Seizo K0ND01954 Volume 60 Issue 708 Pages 400-409
Published: September 25, 1954
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSThe patterns of sedimentation, grain size, and roundness, and mineralogical composition of the Kwanto loam in Shimosa terrace land, Chiba prefecture, Japan were studied., The Kwatno loam is stratified upon the sandy gravel bed which lies on the Narita formation, and mainly consists of rock fragments of weathered basic tuff., The Kwanto loam is classified into two groups, the upper and the lower A pumice bed lies about 20 cm above the bottom of the upper Kwanto loam (Fig., 1)., The mean grain size of the upper Kwanto loam by weight percentage is bout 3., 6∼3., 8 Phi in diameter while the lower Kwanto loam is 2., 8∼3., 2 Phi., The variation in grain size in the upper Kwanto loam is far less than in the lower (Table 2)., The frequency polygons in Fig., 3 show the difference between the upper and lower., The roundness in the upper Kwanto loam varies from 0., 20 to 0., 22 while in the lower from 0., 33 to 0., 37 (Fig., 5)., The two loams can be distinguished fairly well by their mineralogical composition., The upper Kwanto loam rich in mafic minerals, such as olivine and pyroxene, while the lower is rich in felsic minerals (Table 3)., From the evidence just mentioned, it may be inferred that the upper Kwanto loam is aeolian while the lower is aqueous, and there is a time interval of sedimentation between these two loams.,View full abstractDownload PDF (1058K)
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