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Volume 48 (1962)
- Issue 6 Pages 207-
- Issue 5 Pages 167-
- Issue 4 Pages 123-
- Issue 3 Pages 77-
- Issue 2 Pages 37-
- Issue 1 Pages 1-
Volume 48, Issue 2
Displaying 1-4 of 4 articles from this issue
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Hiroshi Abe1962 Volume 48 Issue 2 Pages 37-48
Published: August 05, 1962
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSThe ore deposits of the Abuta mine are bedded bodies composed of iron sulphide ore associated with sulphur and limonite in the Pliocene andesite lava flows. The ore consists of pyrite, marcasite, melnikovite, sulphur, goethite, hematite and hydrohematite intimately accompanied by chlorite, saponite, montmorillonite, sericite, kaolin, alunite, jarosite, opal, cristobalite, quartz, gypsum, barite, cinnabar, rutile, siderite and melanterite. The alteration of wall rocks, such as silicification, alunitization, kaolinization, montmorillonitization, saponitization and chloritization shows zonal distribution around the ore bodies. This zonal arrangement is probably due to the difference in the solutions which followed the same path at different times. The relation between mineralization and the various stage of alteration in time and space has been stressed in this paper.View full abstractDownload PDF (2525K) -
Hanzo Gohara1962 Volume 48 Issue 2 Pages 49-59
Published: August 05, 1962
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSPyrrhotites of Japan have been studied with special reference to their magnetic properties. The important conclusions are as follows:
(1) The curie point of pyrrhotite is 305°to 320°C.
(2) The magnetic susceptibility of pyrrhotite increases with their atomic ratio of sulphur, and can be divided into the following three growps, 1, 000_??_11, 000×10-6, 11, 000_??_20, 000×l0-6 and >20, 000×10>-6.
(3) From the magnetization-temperature curve, pyrrhotites can be classified into following three groups by their temperature dependency of magnetism: (a) Peak type: α-pyrrhotite with weak magnetism, (b) Weiss type: β-pyrrhotite with strong magnetism which shows no peak on a I-T curve, (c) Peak+Weiss type: mixture of α- and β-pyrrhotites.
(4) Peak type pyrrhotite is converted from weak magnetic to strong magnetic by heating and converted mineral becomes to Weiss type pyrrhotite above the curie point.
(5) Peak type pyrrhotite occurs abundantly in the hydrothermal veins, while weiss type is very frequent in the Kieslager type deposits. This indicates that the peak type pyrrhotites formed primarilly in the hydrothermal veins are transformed secondarily to Weiss type by the later metamorphism.View full abstractDownload PDF (1018K) -
Kazuo Harada1962 Volume 48 Issue 2 Pages 60-66
Published: August 05, 1962
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSThe writer surveys the Doshinkubo ore deposits of the Chichibu mine, which belongs to the magnetite deposits of the pyrometasomatic type consisting of pyrite, pyrrhotite, chalcopyrite, and some silicate skarn minerals. At the contact between the quartz-diorite and limestone, the following zones of mineral association were recognized by megascopic and microscopic observations.
Zone 1: quartz-diorite, which is composed of quartz, plagioclase (An45 Ab55_??_An55 Ab45), brown hornblende, biotite and blue actinolite.
Zone 2: mixed rock zone (width; 20_??_30cm.), which is composed of quartz, plagioclase, brown hornblende, diopside, garnet, chlorite, and calcite.
Zone 3: vesuvianite-xanthophyllite zone (width; about 2m), which is composed of vesuvianite, diopside, wollastonite, garnet, and xanthophyllite.
Zone 4: garnet-chlorite-epidote zone (width; about 10m.), which is composed of andradite, pistacite, and chlorite.
Zone 5: magnetite ore body (width; about 30m.).
Zone 6: hedenbergite-ilvite zone (width; about lm.).
Zone 7: limestome.
The occurrence of the Zones 2 and 3 are closely related, with an intrusive body of the quartz diorite, and those of the Zones 4, 5, and 6 controlled by the formation of the ore body. From the observation mentioned above, the writer suggests that the Zones 2 and 3 were formed by the magmatic “reaction” between the quartz-diorite magma and limestone, but the Zones 4, 5, and 6 may be the products of the mineralization at the later stage.View full abstractDownload PDF (1232K) -
Satoshi Kanisawa1962 Volume 48 Issue 2 Pages 67-75
Published: August 05, 1962
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSThe Ryoke metamorphic rocks of the Takato district are composed mainly of pelitic and psammitic rocks, with subordinate amounts of basic volcanic rocks and limestone.
The grade of metamorphism of the district increases progressively from the northwest to the southeast.
Petrofabric analysis has been carried out for biotite, muscovite and quartz in the pelitic schistose hornfelses and gneisses of the district. Biotite and muscovite fabrics are generally determined by the bedding schistosity, and quartz fabrics of the schistose hornfelses show weak symmetry and ac-girdle, while those of the gneisses do not show any symmetrical pattern.
When compared with those of the Yanai district belonging to the Ryoke metamorphic belt in southwestern Japan, the fabric diagram mentioned above are less symmetrical. This fact may suggest that the movement during the Ryoke metamorphism was different between the Takato and the Yanai districts.View full abstractDownload PDF (432K)
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