1993 Fiscal Year Final Research Report Summary
Study on the Origin of Ore-Forming Fluid by Hydrogen Isotope Measurement of Fluid Inclusions
| Project/Area Number |
03453057
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
鉱物学(含岩石・鉱床学)
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SHIMAZAKI Hidehiko Univ.of Tokyo, Graduate School of Science Prof., 大学院・理学系研究科, 教授 (50013751)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMIZU Masaaki Univ.of Tokyo, Univ.Museum Assist.Prof., 総合研究資料館, 助手 (50162714)
IMAI Akira Univ.of Tokyo, Graduate School of Science Assist.Prof., 大学院・理学系研究科, 助手 (90223304)
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| Project Period (FY) |
1991 – 1993
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| Keywords | Fluid inclusion / Ore-forming solution / Hydrogen isotopic ratio / Hydrothermal deposit / Material transport / Gold-silver deposit / Meteoric water / Magmatic water |
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| Research Abstract |
1. Sampling and Analyzes of Formation Environments : In Japanese Island Arc, young epithermal gold mineralization occurs frequently, for example the Hishikari gold deposits, and their shallow formation environments are contrasting with gold mineralization of Mesozoic time in Korea and China. Geological informations about these deposits are relatively abundant, and we selected these type of mineralizations as our main target.
2. Establishment of Technique on Hydrogen Isotope Measurement : Through many times trials, we finally decided the following conditions for obtaining hydrogen gas from natural specimens. That is : decrepitation method for the break of fluid inclusion in specimens, -40 mesh - +80 mesh for the size of pulverized specimen, BDH-metal Zn for the reduction of water to hydrogen, about thirty minutes at about 430ﾟC for the reduction.
3. Analysis of the Origin of Ore-forming Solutions : Obtained hydrogen isotopic composition for each mineral deposit could be grouped into two. One group is : hydrogen isotopic values of fluid inclusions fall in a quite narrow range for one deposit. The other group is : hydrogen isotopic values have quite a large variation range even for one deposit. For the former group deposits, magmatic, metamorphic, ocean or meteoric water could be assigned as an origin of water depending on the values. For the latter group deposits, mixing of two or more types of waters, and possibly boiling of the water also, could be cited as a cause of complex isotopic features.
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