Hydrogen isotopic composition of MnO(OH) minerals from manganese oxide and massive sulfide (Kuroko) deposits in Japan
✍ Scribed by Yu Hariya; Makoto Tsutsumi
- Publisher
- Springer
- Year
- 1981
- Tongue
- English
- Weight
- 629 KB
- Volume
- 77
- Category
- Article
- ISSN
- 0010-7999
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✦ Synopsis
The hydrogen isotopic composition of structural water in MnO(OH) minerals from manganese oxide and massive sulfide deposits (Kuroko) in Tertiary formations fall within a narrow range from -261 to -275 permil relative to standard mean ocean water (SMOW). The 6D of two manganites from manganese deposits in Paleozoic formations were -236 and -298 permil, indicating a wider range than in those of Tertiary manganese deposits. The MnO(OH) minerals are more deuterium-depleted than any other hydrothermal minerals reported to date.
Hydrogen isotopic fractionation factors between manganite and water were experimentally determined to be 0.7894, 0.7958, and 0.8078 at 150 ~ 200 ~ and 250 ~ C, respectively, under hydrothermal conditions at 500 bars. The present experimental results indicate that if manganites were formed at temperatures below 250~ under isotopic equilibrium conditions, then most manganite mineralization in the ore deposits must have precipitated from meteoric hydrothermal solutions.