1991 Fiscal Year Final Research Report Summary
Hydrogen isotopic partition study between water in magma and hydrous minerals
| Project/Area Number |
01540655
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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 |
鉱物学(含岩石・鉱床学)
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| Research Institution | Shinshu University, Department of Geology |
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Principal Investigator |
KURODA Yosjimasu. Shinshu Univ., Dept. of Geology, Professor, 理学部, 教授 (20015530)
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| Co-Investigator(Kenkyū-buntansha) |
HARIYA Yu Hokkaido Univ., Dept. of Geology, professor, 理学部, 教授 (50000815)
YAMADA Tetsuo Shinshu Univ., Dept. of Geology, professor, 理学部, 教授 (30020647)
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| Project Period (FY) |
1989 – 1991
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| Keywords | hornblende / biotite / granite / D / H / isotope / partition / water / X_<Fe> (Fe / Fe + Mg) |
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| Research Abstract |
There were two experimental works on D/H fractionation between water and amphibole or mica under 350 - 950ﾟC and lower than 8 kb. One is Suzuoki and Epstein (1976) and the other is Graham et al. (1984). The former conducted both mica and hornblende and the latter did amphibole. The experimental result by Suzuoki and Epstein was formulated as 10^3alpha_<m-w> = -22.4 x 10^3T^<-2> + 26.3 + (2X_<Al> - 4X_<Mg> - 68X_<Fe>). In the equation biotite and amphibole behave in the same manner, and the deltaD-X_<Fe> relationship between hornblende and biotite is characteristic in the almost all Japanese granitic rocks. This means that the intrusion of granitic rocks in mobil belt or island arc was associated with molecular water under rather high temperature condition(300 - 600ﾟC).
However, according to our experimental data onbiotite of high X_<Fe> value (0.7 0.8 the fractionation of D/H between water and mineral is rather random, and the data on amphibole and by Graham et al. are also not so regular. The reason seems to depend on high value of water used in the experiments, because the mineral with high X_<Fe> is oxidized into magnetite, and hydrogen leaks for the capsules.
Natural granitic rocks as rapakivi in the shield, the deltaD-X_<Fe> relationship between hornblende and biotite is quite different from that of the Japanese granitic rocks. It depends on the absence of molecular water during the intrusion granitic rocks i. e., the granite in the shield derives directly from magma to crystalline upper crust. The D/H fractionation between OH in magma and crystallizing hornblende and biotite is not known.
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[Publications] KANISAWA, S., YOSHIDA, T., ISHIKAWA, K., KURODA, Y., YAMADA, T., MORIKIYO, T., MARUYAMA, T. & AOKI K.: "Preliminary study of the trace elements geochemistry of some Proterozoic granites, Sweden." Res. Report of Lab. Nuclear Sci., Tohoku Univ.24, No. 2. 312-329 (1991)
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