| Project/Area Number |
20K04123
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 17040:Solid earth sciences-related
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| Research Institution | Akita University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
越後 拓也 秋田大学, 国際資源学研究科, 准教授 (30614036)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2022: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2021: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2020: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
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| Keywords | 斑岩銅鉱床 / 鉱脈型銅鉱床 / 東北日本弧 / 資源探査 / 鉱床成因 / 熱水性銅鉱化作用 / 鉱脈型鉱床 / 安定同位体組成 / K-Ar年代 / 硫黄同位体組成 / 熱水 / 銅 / 濃集 / 沈殿 |
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| Outline of Research at the Start |
海洋プレートの沈み込みに伴う火成弧に分布する斑岩銅鉱床や鉱脈型銅鉱床において，銅が濃集・沈殿するメカニズムを，岩石や鉱物の産状と化学組成，鉱物中の流体包有物分析，鉱物の酸素・水素・硫黄同位体組成をもとに解明する．初年度に試料収集と試料調整，および試料を構成する鉱物の記載を行う．2年度には鉱物学的，地球化学的分析を行い，鉱床をもたらした熱水の性質を明らかにする．最終年度には銅の濃集・沈殿をもたらした要因(鉱床形成にかかわったマグマの酸化還元度，熱水中の卓越硫黄種，鉱床形成場の温度圧力条件)を考察し，斑岩銅鉱床，鉱脈鉱床それぞれの形成条件を明らかにする．
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| Outline of Final Research Achievements |
Mechanisms of copper concentration and precipitation in porphyry copper deposits and vein-type copper deposits distributed in igneous arcs associated with the subduction of oceanic plates are investigated. In the first year, we collected and prepared samples, and described the minerals that make up the samples. In the second year, we conducted mineralogical and geochemical analyses, and clarified the properties of the hydrothermal fluid that caused the deposits. In the final year, the factors that brought about the concentration and precipitation of copper (the degree of magma oxidation-reduction involved in the ore formation, the dominant sulfur species in hydrothermal fluid, temperature and pressure conditions of the ore-forming fluid, and the composition of oxygen and hydrogen) were investigated. Then the origin of the mineralized fluid was discussed, and the difference in the formation conditions of porphyry copper deposits and vein deposits was clarified.
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| Academic Significance and Societal Importance of the Research Achievements |
斑岩銅鉱床の形成される地質，地球化学条件が明らかにされ，今後の銅資源探査に応用することができる．得られた結果は，斑岩銅鉱床が天水の循環しない静岩圧下の高温熱水から形成されることが明らかになった．このような地質条件は圧縮応力下の火山弧であり，このような地質条件を満たす地域が今後の資源探査のターゲットとなりうる．
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