1995 Fiscal Year Final Research Report Summary
Alteration of feldspars and its effect on element distribution
| Project/Area Number |
06640620
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | The University of Tokyo (1995)
Ehime University (1994) |
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Principal Investigator |
MURAKAMI Takashi The University of Tokyo, Graduate School of Science, Associate Professor, 大学院・理学系研究科, 助教授 (00253295)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Tsutomu Japan Atomic Energy Research Institute, Department of Environmental Safety Resea, 環境安全研究部, 研究員
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| Project Period (FY) |
1994 – 1995
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| Keywords | Feldspar / Weathering / Dissolution / Water-rock interaction |
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| Research Abstract |
Alteration of feldspars was examined on the emphasis of the difference in dissolution rates between laboratory and field, and that the effects of alteration on the element distribution. Anorthite, orthoclase and albite crystals were used for hydrothermal experiments, where they were interacted with water at 90-210 C for 3-210 days. In order to compare the secondary minerals, weathered granites were sampled.
Boehmite, a boehmite like phase, and kaolinite occur as the dissolution proceeds. The boehmite like phase has an Si/Al cation ratio of 1/30-1/3, and a sub structure of boehmite with a superstructure. The electron diffraction pattern of the superstructure varies with a composition. The boehmite like phase occurs as a metastable one in the feldspar group mineral dissolution at the condition where boehmite is precipitated, and controls the dissolution after boehmite is not stable against the water.
The surface of Plagio clase and orthoclase in the granites were examined by SEM-EDX.Although the bulk water weathering the granite seems to approach to be equilibrated with kaolinite, the primary minerals are accompanied by different secondary minerals. This is attributed to the preferential dissolution occurring in fissures and defects, which leads to the difference in local water chemistries.
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[Publications] Murakami, T., Ohnuki, T., Isobe, H., Sato, T,, Yanase, N., Kimura, H.: "Significance of mineral alteration on nuclide migration" Mat.Res.Soc.Symp.Proc.333. 645-652 (1994)
Description
「研究成果報告書概要(欧文)」より
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[Publications] Murakami, T., Isobe, H., Ohnuki, T., Sato, T., Yanase, N., Kiyoshige, J.: "Mechanism of saleeite formation at the Koongarra secondary ore deposit" Mat.Res.Soc.Symp.Proc.(in press).
Description
「研究成果報告書概要(欧文)」より
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