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Volume 41 (1957)
- Issue 6 Pages 211-
- Issue 5 Pages 173-
- Issue 4 Pages 129-
- Issue 3 Pages 89-
- Issue 2 Pages 43-
- Issue 1 Pages 1-
Volume 41, Issue 3
Displaying 1-4 of 4 articles from this issue
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Toshinori Matsukuma, Michitoshi Miyahisa1957 Volume 41 Issue 3 Pages 89-97
Published: June 01, 1957
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSDownload PDF (1953K) -
Hiroshi Asai1957 Volume 41 Issue 3 Pages 97-106
Published: June 01, 1957
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSIn this paper the writer presents some considerations of the genesis of some cordierites in the cordierite bearing biotite migmatite and in the biotite bearing spinel cordierite oligoclasite and in the garnet bearing cordierite hypersthene biotite gneiss as well.
The cordierite occurs as a product between the sheared porphyroclast of the plagioclase and the younger biotite which concentrates at the mechanical movement in the later stage of formation of every metamorphic rock.View full abstractDownload PDF (1502K) -
Yono Sotozaki1957 Volume 41 Issue 3 Pages 107-116
Published: June 01, 1957
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSThe gneisses of this district are classified, according to the structural views, into three main types as follows: 1. banded gneiss, 2. gneissose migmatite, and 3. schistose rock. The general trend of the rocks is NW-SE and the dip is 40°_??_60° NE. The banded gneiss occurs as a narrow belt along the marginal zone of the cordierite migmatite mass, while the gneissose migmatite and the schistose rock occur in the migmatite area. The banded gneiss and the gneissose migmatite are composed mainly of medium- to coarse-grained metamorphics such as biotite gneiss, garnet sillimanite-bearing cordierite muscovite biotite gneiss, kalifelspar biotite gneiss, tourmaline-bearing muscovite biotite gneiss, and sillimanite muscovite biotite gneiss, etc. The schistose rock is dark brown, and shows schistose or hornfelsic texture. It is composed of finegrained quartz, plagioclase, and biotite, containing muscovite, kalifelspar, and rarely garnet and tourmaline. In this paper, the results of volumetric relation of chief mineral constituents and plagioclase twin method are described and mutural relationships of the rocks are discussed.View full abstractDownload PDF (1021K) -
Especially on the wall-rock alterationHirosi Omure1957 Volume 41 Issue 3 Pages 116-128
Published: June 01, 1957
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSOre deposits of the Numanoue mine located in eastern Hokkaido, are typical epithermal gold-silver bearing quartz veins in the Neogene Tertiary. The country rocks of the ore deposits are liparitic rocks which are widely distributed throughout the vicintiy.
The veins are divided into two types: one filling up along the faults and the other filling up the fissures. Thus, these types are dissimilar in some diminsions and structures of the veins. It is considered that the veins were made by at least two mineralizations. In the first mineralization, siliceous solution did not contain useful elements, and in the second mineralization useful minerals which are gold, silver and sulphide minerals (except pyrite) were deposited. Gangue mineral is chiefly quartz. In those ore deposits, various wall-rock alterations had occurred before the vein formation. Remarkable alterations are silicification, aduraliazation, chloritization and sericitization. Silicified-aduralized rocks and chloritized rocks develop in the central part of the liparite body and they show a banded distribution. Sericitized leek is distributed in the southwestern part of the one.
The veins formed in the altered rock body, usually have a banded structure. The various vein characters have close relation to the features of the altered rocks, and most of the ore shoots are found in chloritized rocks.
Moreover, it is a distinctive character of the ore deposits that both wall-rocks and veins are remarkably oxidized.View full abstractDownload PDF (3720K)
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