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Volume 56, Issue 653
Displaying 1-8 of 8 articles from this issue
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Wataru Ichikawa1950 Volume 56 Issue 653 Pages 49-56
Published: June 25, 1950
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSFossil diatoms are remarkably abundant, both as to genera and as to species, in the Tertiary sediments and in the present lakes, seas, and oceans, However, the significance of these fossils in the stratigraphy of the Tertiary formations has been somewhat neglected due to the fact that they are cosmopolitan and invariable., The purpose of the present article is to find out if the Tertiary Diatomaceae of Japan are of stratigraphic significance, and to show the relationship existing among the Tertiary deposits in certain parts of the Peninsula and the vicinity of Kanazawa city., The chief localities selected by me in these districts are : Iizuka, Tsukada, Wakura, Yamatoda, Awara, Hijirikawa and Mitsukoji., The diatom-bearing mudstones in the six localities, except Yamatoda, are characterized by marine species for the most part, and they represent the same geological horizon., The ages of these mudstone beds are somewheve in the late Miocene or early Pliocene according to the abundant data of other geologists., Among the fossil diatoms the genus Coscinodiscus is a dominant form., The other fossils include sponge spicules, Radiolaria and, Silicoflagellata., The species Dictyocha fibula and Dictyocha speculum belonging, to Silicoflageliatae are characteristic of the recent cold water in the Northern Japan Sea., The diatom-bearing mudstones of these six localities are of marine origin, and all of them were deposited by cold currents., The Yamatoda mudstone is of brackish origin., My studies of the constitution of diatom plankton leads to the conclusion that the Yamatoda mudstone beds were deposited in a half enclosed bay.,View full abstractDownload PDF (1003K) -
Kokiti Isioka, Setuo Kamei1950 Volume 56 Issue 653 Pages 57-58
Published: June 25, 1950
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSLimestone and conglomerate exposed at Oise-dani, Kamianauma-mura, in the upper part of Kuzuryu River, were found to contain fossil corals of Gotlandian age., Among the pebbles of the conglomerate the writers found diallage-gabbro., A quite similar rock occurs enclosed, probably as an intrusive mass, in cherty schalstein nearby., It follows then that there was an intervening period of erosion between the deposition of the cherty schalstein and the Gotlandian conglomerate., A complex of crystalline-schists, consisting mainly of epidote-amphibole-schists, is also exposed in the vicinity., It grades into gneissic hornblende-epidote-quartz-diorite where it has undergone lit-par-lit injection by acidic magma., The gneissic quartz-diorite resembles closely one of the commonest types of the so-called Hida gneisses, the age of which is yet unknown, The crystalline-schist complex is everywhere separated from the Gotlandian sediments by intrusive masses of serpentinite, so that their age relationship cannot be determined by the present surbey.,View full abstractDownload PDF (409K) -
Takao Sakamoto1950 Volume 56 Issue 653 Pages 59-69
Published: June 25, 1950
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSA colloidal aluminosilicate complex with a given composition becomes a fixed deposit in a certain environment in the weathering crust on the earth's surface, as a non-dispersive isoelectric precipitate, according to the acidity of that environment., The writer proposes that its distribution in nature can be summarized, in a general manner, by "Isosials" or "Equal Silica-Alumina Molecular Ratio Lines"., It is controlled by meteorological factors and hence there is a regular harmony among different climatic zones, the fullest developed being a laterite profile in the tropics., A laterite profile, in the arrangement of its component minerals, resembles the profile of a low temperature hydrothermal alunite deposit., Although the alunitization is caused by the heat from the earth's interior, or is controlled by the energy of an entirely different source, the similarity is due to the fact that the elements of the chemical reactions, above and below the underground water table on the earth's surface, closely resemble each other., It is also quite natural that there is again a striking similarity between the stability fields of those minerals in the hydrothermal syntheses of silicates, as conducted by Noll and others, and the environments of the formation in the above two profiles in nature., In view of its position with regard to the "ISOSLALS" a bauxite is, no doubt, the product of an extreme weathering, hill tops or cliff edges on a level land and a tropical monsoon being the optimum for its formation., Stratigraphically, the bed of a redeposited laterite can be reckoned as an abnormal facies of a basal conglomerate., It is because the laterite is an end product of weathering on a level land., The lenticular rich ore bodies of the bando-ketsugan (aluminous shale) are channel deposits on a lake bottom, being comparable with the U, V and Cu bearing clay lenses in the "Red Beds" in the western US., The bando-ketsugan (aluminous shale) and the Koshitsu-nendo (flint clay) beds, are reworked laterite materials in the Upper Paleozoic age in N., China, S., Manchuria and Korea., They reach 20m in their aggregate thickness in most coal-fields, and are the largest of all known ore beds of kaolinite and aluminous hydroxide in the world., This is due to the fact that this region, in the Upper Paleozoic era, formed an extensive sedimentary basin of an epeirogenic type with the gentlest crustal movement in the world., In contrast, the Mesozoic era, in the same region, witnessed the formation of many local sedimentary basins of an orogenic type., The character of those crustal movements accounts for the distinct types of coal ash and the composition of clay colloids deposited in both basins., That is, the coal ash, in the sedimentary basin of an orogenic type, are characterised by the montmorillonite series or the clay minerals in the juvenile stage of evolution, while those in the sedimentary basin of an epeirogenic type, by the kaolinite series or those in the mature stage of evolution., Further, the laterite materials of the bando-ketsugan are clay minerals in the senile stege, or the ones which have the least chance both of formation and preservation in the region of an orogenic movement., The writer, in the present paper, proposes the term and concept of "Isosials" which, representing a regular arrangement of soil colloids in the generalized soil profile covering the Frigid and Tropical zones, point to the "evolution" of clays., He has also illustrated that the types of coal ashes, when represented by clay minerals in different stages of the evolution, reflect different types of crustal movements to which the coal basins are due.,View full abstractDownload PDF (1482K) -
Tami INOUE1950 Volume 56 Issue 653 Pages 71-77
Published: June 25, 1950
Released on J-STAGE: April 11, 2008
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Hisashi KUNO1950 Volume 56 Issue 653 Pages 79-83
Published: June 25, 1950
Released on J-STAGE: April 11, 2008
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[in Japanese]1950 Volume 56 Issue 653 Pages 83-84
Published: June 25, 1950
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSDownload PDF (366K) -
Hisashi KUNO1950 Volume 56 Issue 653 Pages 85-87
Published: June 25, 1950
Released on J-STAGE: April 11, 2008
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Lloyd W. STEPHENSON1950 Volume 56 Issue 653 Pages 89-94
Published: June 25, 1950
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSDownload PDF (828K)
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