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Volume 71, Issue 7
Displaying 1-4 of 4 articles from this issue
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JUJIN SUZUKI, MASAHIRO ITO, TSUTOMU SUGIURA1976 Volume 71 Issue 7 Pages 183-192
Published: July 05, 1976
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSNakauriite is a new mineral found as fissure-fillings in serpentinite. There are two types appearing in different modes of occurrences, and showing a few faint differences in X-ray diffraction and DTA patterns. Both show very fine needle-like and prismatic forms with characteristic sky-blue color. It is effervescent in HCl, H2SO4 and HNO3 Chemical analysis gave Mn0.019 Ni0.231 Cu7.770 (SO4)3.904 (CO3)(OH)6.232 48.4H2O or (Mn, Ni, Cu)8(SO4)4 (CO3)(OH)6 48H2O as C=1 for empirical cell contents. The most intense X-ray diffraction lines (in Å) are 7.31 (100), 4.840 (14), 3.936 (14), 3.652 (20), 3.552(13), 2.397 (14), 2.367 (16), 2.332(14) and 1.9148 (16). The 7.823Å-line appears with variable intensities. Nakauriite is pleochroic, X=colorless, Y=very light greenish blue, Z=pale sky-blue to very light blue. The mineral is biaxial negative with α=1.585, β=1.604, γ=1.612 (all±0.001), 2V(-)=65.3 (calc.), showing positive elongation. Extinction is parallel to the outline. Five endothermic reactions are found at 78, 150, 186, 330 and 396°C of peak maxima, respectively, the last two being characteristically strong. Infrared absorption gives two characteristic bands at 3000 and 1360 cm-1. The name is for the locality.View full abstractDownload PDF (1986K) -
KAZUO NAKAMURA, SHIN-ICHI HIRANO, SHIGEYUKI SOMIYA1976 Volume 71 Issue 7 Pages 193-200
Published: July 05, 1976
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSBrucite crystals were grown hydrothermally from Mg(OH)2 powder in 7.5 and 15 mol% NaOH solutions. It is established from the obsevation of the surface microtopographs that the crystals grew by the spiral mechanism. The filling degree of numerous fluid inclusions in the crystals grown under various conditions of pressure, temperature and concentration of solution are measured. The P-T-F.D. relations of NaOH solution are discussed on the basis of these measurements.View full abstractDownload PDF (2099K) -
Naotatsu Shikazono1976 Volume 71 Issue 7 Pages 201-215
Published: July 05, 1976
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSThe chemical composition of kuroko ore-kuroko ore-forming solution is estimated on the basis of silicate-solution equilibrium and electroneutrality relation in the solution. Characteristic features of the model ore-forming solutions by the present author are compared with those of the other possible ore-froming solutions such as the model ore-forming solutions by the other workers, hydrothermal solution accompanied by the present-day base metal deposition, fluid inclusions, and hydrothermal solution derived from basalt/seawater reaction experiments. In general, alkali, and alkali earth elements concentrations of the model oreforming solution are similar to those of the other possible ore-forming solutions, if Clconcentration and temperature are same. However, in general, heavy metal elements concentrations of the model ore-forming solution are different from those of the other possible ore-froming solutions. It is notable that alkali, alkali earth, and heavy metal elements concentrations of some fluid inclusions are nearly same to those of the model ore-forming solution.View full abstractDownload PDF (651K) -
Hiroshi Konno, Mizuhiko Akizuki1976 Volume 71 Issue 7 Pages 216-220
Published: July 05, 1976
Released on J-STAGE: August 07, 2008
JOURNAL FREE ACCESSDeep green saponites have been found in geode of andestic basalts from Sendai, Japan. The mineral has been confirmed by X-ray diffraction, D.T.A. and chemical analyses. Scanning electron microscopy shows them as small sphelurites. The structural formula of the mineral is given as
Ca0.35(Mg3.02Fe2+3.03Ti0.04Mn0.04Al0.01)(Si6.89Al1.11)O20(OH)4
The results show that the mineral is the richest in Fe in saponites descried up to data and Fe2+/Mg2+=1.003. It may be thought that the saponites grow rapidly on small nucleuse under hydrothermal condition, resulting in spherulites.View full abstractDownload PDF (2025K)
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