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Volume 54, Issue 1
Displaying 1-4 of 4 articles from this issue
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Yotaro Seki1965 Volume 54 Issue 1 Pages 1-13
Published: July 05, 1965
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSSome detailed statistical analysis of mineral assemblages of mafic schists in low-grade regional metamorphic terrains of Japan show that
(1) Partial pressure of chemical potential of CO2 must have clearly controlled the mineral associations formed in low-grade regional metamorphic rocks,
(2) CO2 pressre varies with areas as well as with grade of regional metamorphism.View full abstractDownload PDF (569K) -
Humio Sato, Hiroshi Shirahata1965 Volume 54 Issue 1 Pages 14-22
Published: July 05, 1965
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSThe geological survey and laboratory work were carried out on the granitic rocks in southwestern Hokkaido for past several years by authours. Sixteen granitic rocks were newly analyzed chemically by them. The present paper deals with the chemical and mineralogical compositions of the granitic rocks in the relation with their occurrence. Most of granitic rocks in southwestern Hokkaido belong to granodiorite chemically and mineralogically.
The granitic rocks from the main zone including those of Imagae, KudoSetana, Kumaishi and Matsumae show the similar characteristics chemically and mineralogically. However those from Okushiri at the west side of main zone and from Shi-ôtaki, Kagenosawa and Kayanuma at the east side are different from those of the main zone in the chemical characteristics, although they can't be distinguished mineralogically from the granitic rocks of the main zone. It is significant that the granitic rocks of Shinôtaki, Kagenosawa and Kayanuma intruded in Miocene or far later than the others.View full abstractDownload PDF (380K) -
Tokiko Tiba1965 Volume 54 Issue 1 Pages 23-31
Published: July 05, 1965
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSThe alkaline rocks of the Takakusayama district, Shizouka Prefecture, central Japan, form flows, dikes and shallow intrusive bodies in the Paleogene and the lower Miocene formations and are possibly middle Miocene. The rocks vary from undersaturated alkali olivine basalt and analcite-titan-augite-olivine dolerite through mugearite to oversaturated trachyte and sodatrachyte.
Main constituent minerals of these rocks are plagioclase, alkali feldspar, olivine, clinopyroxene, alkali amphibole, kaersutite, iron ores and analcite Clinopyroxenes vary from diopsidic augite through titanaugite to salite in the basic rocks but only augite is observed in acidic ones. Alkali amphibole, possibly arfvedosonite, is found in soda trachytic rocks, whereas kaersutite occurslocally in basic rocks. Interstitial analcite indicates that it crystallized at the latest stage of the magmatic crystallization.
Sixteen rocks of this district were chemically analysed. They have a range from 45 to 65 per cent SiO2 and are characterized by high TiO2, Al2O3, Na2O and H2O+contents and low ∑FeO and K2O contents. These features are briefly discussed in comparison with the alkaline intrusive rocks in the other districts of Japan and Sakhalin.View full abstractDownload PDF (539K) -
Jun-ichi Kitahara1965 Volume 54 Issue 1 Pages 32-38
Published: July 05, 1965
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSHydrophlogopite apperas at a contact zone between a diorite dyke and harzburgite in the Chgiri level of 7th deposits of the Wakamatsu mine. It is believed that the hydrophlogopite is the product of hydrothermal metamorphism related to igneous emanations. The chemical formula of the hydrophlogopite is shown in the present paper. It seems clear that the mineral is a regualr mixed layer type composed of phlogopite and vermiculite. The γ index of the present mineral is 1.6051, and the calculated value is 1.604. The lattice constant d (001) is 24.3 A.View full abstractDownload PDF (777K)
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