Geological interpretations from heterogeneously distributed iodine deposits
| Project/Area Number |
17K05703
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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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| Research Field |
Petrology/Mineralogy/Economic geology
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| Research Institution | Chiba University |
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Principal Investigator |
TOMARU Hitoshi 千葉大学, 大学院理学研究院, 准教授 (80588244)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2017: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
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| Keywords | ヨウ素 / 放射性ヨウ素同位体 / 地下水 / 北海道 / 千葉 / 沖縄 / 放射性同位体 |
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| Outline of Final Research Achievements |
Concentration and radioactive isotopic composition (129I/127I) of iodine have been determined for fluid samples collected from hot springs in Hokkaido, Chiba, and Okinawa where the iodine is often enriched in deep brines. The concentration of total iodine is relatively high in the samples from Okinawa compared with Hokkaido and Chiba samples and seawater, reflecting the potential release from carbonates widely distributed in the research area. The isotopic composition is significantly low in the samples from Chiba, indicating the contribution of deep/old iodine derived from organic-rich source sediments. Distribution and behavior of stable and radioactive iodine is useful for identifying the sedimentary environment and diagenetic processes of iodine-rich fluids.
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| Academic Significance and Societal Importance of the Research Achievements |
ヨウ素は世界的にも分布が偏っているだけでなく、その化学種も場所によって大きく異なる。日本は世界有数のヨウ素濃集地域であり、そのほとんどが水溶性ガスに伴うかん水に溶存した形で産出する。本研究は、ヨウ素と他のハロゲンの濃度（分布）とあわせて、ヨウ素の放射性同位体比（129I/127I）を測定することによって、ヨウ素が濃集していた海洋有機物の相対的な堆積年代として、周囲の堆積物の特徴との比較が可能であることを明らかにした。これは、ヨウ素の動態解析の、地球科学分野における年代法、古環境・堆積環境指標としての応用可能性を強く支持するものである。
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Report
(4 results)
Research Products
(5 results)
