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Volume 17 (1983)
- Issue 6 Pages 269-
- Issue 5 Pages 223-
- Issue 4 Pages 165-
- Issue 3 Pages 111-
- Issue 2 Pages 63-
- Issue 1 Pages 1-
Volume 17, Issue 3
Displaying 1-4 of 4 articles from this issue
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Akihiko Hashimoto1983 Volume 17 Issue 3 Pages 111-145
Published: June 20, 1983
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSEvaporation experiments were performed in vacuo on the multicomponent melt, FeO-MgO-SiO2-CaO-Al2O3 with the solar elemental abundances. The analysis of experimental results shows that the rate-determining step of evaporation is the vaporization reactions occurring on the melt surface, amongst other possible rate processes. The reaction modes are determined for the components, FeO, MgO and SiO2. FeO, unlike other components, vaporizes through the disproportionation reaction into metallic and ferric irons in the melt phase. ‘Volatility’ is defined as a physical quantity so as to describe the evaporational fractionations of elements. On the basis of this concept, the experimental results of the present and previous works together with thermodynamic data are organized to characterize the evaporation sequence of primitive condensed materials. Its gross feature is the sequential evaporation of the components in the order of Fe, Mg, Si, Ca and Al. The details of the evaporation sequence depend on temperature and initial valences of Fe. The evaporation sequence is comparatively discussed with the condensation sequence of the nebular gas, which has been well examined by previous workers. Both sequences, combined together, provide a basic framework to clarify the chemical fractionation processes which have differentiated primitive materials into the planetary and meteoritic materials. The chemical diversity of chondrules and inclusions in meteorites is interpreted as mainly due to the evaporational or condensational fractionation, but it also invokes other processes such as metal/silicate separation and non-equilibrium reaction with a surrounding gas.View full abstractDownload PDF (10649K) -
Tamotsu Oomori, Kiyoshi Kaneshima, Tatsuji Taira, Yasushi Kitano1983 Volume 17 Issue 3 Pages 147-152
Published: June 20, 1983
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSSynthetic studies of protodolomite were carried out for understanding the conditions of protodolomite formation in sedimentary environments. Protodolomite was tried to be precipitated from concentrated sea water (by evaporating sea water) by adding 0.4M-Na2CO3 solution drop by drop. The obtained minerals were amorphous carbonate, aragonite, Mg-poor calcite, Mg-rich calcite, protodolomite, huntite, monohydromagnesite, monohydrocalcite and trihydrocalcite, depending on the concentrations of calcium and magnesium ions in the brine water, the added amount of sodium carbonate and reaction time. Protodolomite seems to be formed diagenetically from metastable minerals given above. The concentration of carbonate ions, Mg2+/Ca2+ ratio and temperature in a parent solution have an important influence on the formation of calcite type carbonate minerals and the Mg contents of these minerals.View full abstractDownload PDF (1824K) -
Nobuki Takamatsu, Masayuki Imahashi, Kyoko Shimodaira, Hiroshi Kamiya1983 Volume 17 Issue 3 Pages 153-160
Published: June 20, 1983
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSLithium minerals, petalite (Li[AlSi4O10]) and lepidolite (K2(Li, Al)5-6[Si6-7Al2-1O20](OH, F)4), were reacted with seawater and NaCl solutions for 240 hours at 150 to 250°C and with a water/mineral ratio of 25 by weight, to clarify the role of dissolved salts on the enrichment of lithium in natural saline waters such as coastal thermal waters and fossil seawaters. Lithium leaching from the minerals was enhanced with increasing salt concentration and temperature. It was proved from the experiments using various salt solutions that NaCl solution and seawater are effective for the leaching of lithium from rocks and that even the altered seawaters containing low magnesium have the ability to extract lithium from rocks. This investigation suggests that the non-volcanic saline waters of high lithium content (e.g. fossil seawater) can be produced by a long term seawater-rock interaction at relatively low temperature without a contribution from the so-called “magmatic emanation”.View full abstractDownload PDF (2235K) -
Yoshihiko Mizutani1983 Volume 17 Issue 3 Pages 161-164
Published: June 20, 1983
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSThe fumarolic condensate and hydrogen gas samples collected from the Showashinzan, Nasudake, Yakedake and Kuju-Ioyama volcanoes, Japan, have been analyzed for the D/H ratio. A comparison between temperatures for isotopic equilibrium and measured outlet temperatures indicates that in high temperature fumarolic gases the deuterium exchange reaction between water vapor and hydrogen gas is rapid enough to readjust the equilibrium to the outlet temperature of fumaroles. For low temperature fumarolic gases, however, the isotopic temperature refers to equilibrium conditions deep in the fumarole.View full abstractDownload PDF (1010K)
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