2000 Fiscal Year Final Research Report Summary
A sulfur isotopic study of sulfate in acid mine drainage and its host sulfur
| Project/Area Number |
11680523
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | Iwate University |
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Principal Investigator |
MAKI Yonosuke Fac.Hum. & Social Sci. Iwate University Prof., 人文社会科学部, 教授 (90048520)
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| Co-Investigator(Kenkyū-buntansha) |
MIZOTA Chitoshi Fac.Agr. Iwate University Prof., 農学部, 教授 (10089930)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Kuroko / Sulfide Ore / Sulfur Isotopic Composition / Isotopic Fractionation / Sulfur-oxidizing Bacteria / Acid Mine Drainage |
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| Research Abstract |
Sulfur isotopic compositions were determined on both of host sulfur and sulfate in acid mine drainage of sulfur mine locating in Hokkaido, Northern Tohoku district, Yamagata-Ken and Okayama-Ken. Sulfates in drainage were precipitated and quantitatively recovered as barium sulfate. Sulfides in minerals were oxidized to sulfates with hydrogen peroxide, and elemental sulfur was combusted in a Parr Bomb #1108. The dried barium sulfate was convented to sulfur dioxide by the terminal decomposition method. ^<34>S/^<32>S ratios were determined using a dual inlet mass spectrometer at the Institute for Study of the Earth's Interior, Okayama University. Based on sulfur isotopic compositions and morphology of ores, mines in Hokkaido and Northern Tohoku district were divided into two groups. The one was small in isotopic variations, and the isotopic compositions of drainage were lower than the host rock indicating isotopic differentiation. Black ore and sulfides in vein were associated with these mines. The other group showed large isotopic variations and was corresponded to ores of natural sulfur and/or black pyrites in mass. The isotopic values of drainage were altered variously against its host rocks. In both Yamagata-Ken and Okayama-Ken, the sulfur isotopic compositions of drainage were also lower than its host rocks. These results suggested strongly the participation of microbes in the processes of sulfur-oxidation under natural conditions.
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