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Volume 55 (1966)
- Issue 6 Pages 221-
- Issue 5 Pages 185-
- Issue 4 Pages 145-
- Issue 3 Pages 79-
- Issue 2 Pages 39-
- Issue 1 Pages 1-
Volume 55, Issue 4
Displaying 1-5 of 5 articles from this issue
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HIROSHI ISOMI, MASTAO KATADA, Ei OMORI, TEIKO OMORI1966 Volume 55 Issue 4 Pages 145-159
Published: April 05, 1966
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESS1) The seven samples of the Permian graywacke from Kiso including the usual type as well as three unusual sub-types were chemically analysed (Table 1).
2) On these data, the new weighted average composition was calculated (Table 2) by the occurrence frequency of each type.
3) By comparing the weighted average with Pettijohn's a v erages of graywacke and arkose, it was concluded that the chemical composition of our graywacke is intermediate between the common graywacke and arkose.
4) Though our graywacke chemically lies between the graywacke and arkose and is rather arkosic with respect to mineral composition, its texture (moderate amount of matrix, angular or irregular shape of grain, ill-sorting) is typical of the graywacke. Furthermore, the lithological association and mode of occurrence are obviously eugeosynclinal.
5) The most remarkable characteristics of the chemical composition of our graywacke, which are very rarely seen in the general graywacke, are a) an excess of K2O over Na2O, b) paucity of iron oxides and magnesia, and c) high CaO and CO2.
6) The predominance of K2O over Na2O corresponds with the presence of clastic K-feldspar in a considerable amount (10_??_16% or more). This singularity implies the paucity of clastic contribution from the geosynclinal basic volcanics and greenstones. The predominance of the granitic and metamorphic provenance is supported by consideration on the mineral composition.
7) The paucity of iron oxides and magnesia collaborates with an excess of K2O over Na2O to suggest the above-mentioned nature of the provenance.
8) The high contents of CaO and CO2, are due to the presence of clastic carbonate grain in more amount than in the common graywacke. An approximate direct proportional relation of carbonate detritus (CaO and CO2) to chert fragment (SiO2) is recognized.
9) Two chemical analyses of the metamorphosed graywacke of the common type were also reported.View full abstractDownload PDF (817K) -
Perlites from Okushiri IslandHumio Sato, Hiroshi Shirahata1966 Volume 55 Issue 4 Pages 160-168
Published: April 05, 1966
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSPerlites, naturally occurring phenomena of Okushiri Island, can be divided into the following three types by their petrographic features:
A. massive type.
B. pumiceous type.
C. flow-textured type.
They are very similar to each other in petrochemical character. Perlites from Okushiri contain large quantities of microlite, crystallite and small amounts of phenocrysts which consist of oligoclase, quartz and biotite. Based on X-ray spectrographical analysis and optical examination it can be deduced that the microlite essentially consists of oligoclase, albite and cristobalite with small amounts of biotite and quartz. A comparison study of Okushiri perlites to microlite indicates that perlite is less crystalline in structure than microlite. Okushiri perlites and those from other parts of Japan, although poor in CaO content, are rich in alkalies, especiallyin K2O and when plotted against the ternary eutectic point on the Q-Or-(Ab+An) triangular diagram devised by Bowen and Vogt. Also, the (Fe2O3+FeO)-(Na2O+K2O)-MgO triangular plot indicates that perlites concentrate near the apex (Na2O+K2O) listed in Kuno's hypersthenic rock series. Okushiri perlites are easily transformed into natural glass by heating and rapid cooling into a solid state. Thus producing a glass of high alkalies and silica similar to magma which has undergone the same physical transformations. As founded by differential thermal and thermogravimetric analyses, the H2O content was gradually dehydrated.View full abstractDownload PDF (366K) -
Makoto Shima1966 Volume 55 Issue 4 Pages 169-173
Published: April 05, 1966
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSHokutolite is particular interest of the hot spring deposit mineral with native radioactive elements. A discussion is given of preliminary results of an X-ray microanalyser on Hokutolite which found in Tamagawa Hot Spring, Akita Prefecture. The Ka pictures of Ba, Pb, and S show the homogeneous distribution of these elements in white and brown layeres of the sample. The FeKa image shows a vein-type distribution in the white layer. On the relation of Fe, Pb, and radioactive elements, the author have tried to suggest possible avenues for the future study.View full abstractDownload PDF (778K) -
Yotaro Seki, Hiroshi Haramura, Hitoshi Onuki, Kimio Okumura, Hachiro H ...1966 Volume 55 Issue 4 Pages 174-178
Published: April 05, 1966
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSWairakites in Miocene andesitic-basaltic pyroclastic rocks of the Tanzawa Mountain and Yugami districts are very close to CaAl2Si4O122H2O in chemical composition.View full abstractDownload PDF (224K) -
Akiho Miyashiro1966 Volume 55 Issue 4 Pages 179-184
Published: April 05, 1966
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSDownload PDF (354K)
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