The Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists

STUDY ON CHEMICAL COMPOSITIONS OF LUZONITE-FAMATINITE SERIES MINERALS BY ELECTRON PROBE MICROANALYSER

Asahiko Sugaki, Hiromi Shima, Arashi Kitakaze

1978 Volume 73 Issue 3 Pages 63-77
Published: March 05, 1978
Released on J-STAGE: August 07, 2008

DOIhttps://doi.org/10.2465/ganko1941.73.63

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To reconfirm whether minerals of luzonite-famatinite series form complete solid solution between them as Springer (1969) reported or limited solid solution having immiscibility gap from approximately 10 to 40 mol% Cu₃SbS₄ as Skinner (1960) inferred. 16 samples of luzonite and famatinite from 7 mines in Japan, Formosa and Philippines were examined by electron probe microanalyser (EPMA). The quantitative analytical data by EPMA for the samples are given in Tables 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 and 13.
The specimens from the Hokuetsu mine, Japan and the Mankayan mine, Philippines have most nearly stoichiometric composition of luzonite as from 0 to 3 mol% Cu₃SbS₄. They from the Lobo mine, Philippines and the Kinkaseki mine, Formosa have from 2 to 12 mol% Cu₃SbS₄, and from 2 to 7 or 36 to 41 mol% Cu₃SbS₄ in composition, respectively. Also luzonite-famatinite series minerals from the Teine, Kasuga and Akeshi mines, Japan have compositions of such wide range as from 19 to 71, 26 to 82 and 3 to 78 mol% Cu₃SbS₄, respectively. However, the composition corresponding to stoichiometric Cu₃SbS₄ of famatinite was not found during this study.
Analytical data for 378 points in 16 specimens are summarized as shown in Fig. 5, and it is found that there is existance of minerals having continuous compositions between luzonite and famatinite except nearly famatinite end. Therefore it is concluded that the complete solid solution between them exists at low temperature as the result of Springer's examination.

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BEHAVIOUR OF FLUORINE IN SOME TERTIARY DOLERITE SILLS, JAPAN

Satoshi Kanisawa, Ken-ichiro Aoki

1978 Volume 73 Issue 3 Pages 78-81
Published: March 05, 1978
Released on J-STAGE: August 07, 2008

DOIhttps://doi.org/10.2465/ganko1941.73.78

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Abundances of fluorine in some Tertiary dolerite sills in Japan have been determined using a slective ion-electrode in order to clarify the behaviour of fluorine in basaltic magma with advancing differentiation. The Hatozaki alkali-dolerite sill, the Odate olivine dolerite sill taken from the bore hole (HO-1) and the Otaki olivine dolerite sill in northeast Japan have 206, 225 and 283 ppm of average fluorine content in the main mass, while 427, 314 and 469ppm in the late differentiates respectively. The Murotomisaki gabbro in southwest Japan has 77ppm of average fluorine content in the main mass and 137 ppm in the late differentiates. All dolerite sills studied show the tendency that the fluorine content increases with advancing differentiation. The relation between fluorine content and P₂O₅ shows distinct positive correlation in the rocks of the Odate and the Otaki sills, while does not show any distinct correlation in the Hatozaki and Muroto masses. The late differentiates of the Hatozaki sill have large amounts of hydrous minerals such as analcime and thomosonite and a little of biotite and hornblende, thus most of fluorine in these rocks may enter into these minerals replacing OH-ion. However, fluorine in the Odate and the Otaki sills may be contained in apatite.

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[title in Japanese]

1978 Volume 73 Issue 3 Pages 83-93
Published: 1978
Released on J-STAGE: July 13, 2012

DOIhttps://doi.org/10.2465/ganko1941.73.83

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