| Project/Area Number |
20340146
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Stratigraphy/Paleontology
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| Research Institution | Toho University (2009-2011)
Japan Agency for Marine-Earth Science and Technology (2008) |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
KATO Yasuhiro 東京大学, 大学院・工学系研究科, 教授 (40221882)
SUZUKI Katsuhiko 海洋研究開発機構, 地球内部変動研究センタ-, グループリーダー (70251329)
KIYOKAWA Shoichi 九州大学, 大学院・理学研究院, 准教授 (50335999)
NEDACHI Munetomo 鹿児島大学, 理学部, 教授 (10107849)
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| Co-Investigator(Renkei-kenkyūsha) |
NARAOKA Hiroshi 九州大学, 大学院・理学研究院, 教授 (20198386)
ITO Takashi 茨城大学, 教育学部, 教授 (10272098)
IKEHARA Minoru 高知大学, 海洋コア総合研究センター, 准教授 (90335919)
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| Project Period (FY) |
2008 – 2011
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| Project Status |
Completed (Fiscal Year 2011)
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| Budget Amount *help |
¥17,940,000 (Direct Cost: ¥13,800,000、Indirect Cost: ¥4,140,000)
Fiscal Year 2011: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Fiscal Year 2010: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Fiscal Year 2009: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2008: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000)
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| Keywords | 太古代 / 堆積岩 / チャート / 縞状鉄鉱層 / 黒色頁岩 / 安定同位体 / 微量元素 / 同位体 / 微生物 |
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| Research Abstract |
From multidisciplinary geochemical studies using the fresh drillcore samples of 3.46 Ga chert and 3.2 Ga chert/BIF/black shales, the following exciting results are obtained. Ferrous iron from hydrothermal venting was oxidized, most likely by dissolved oxygen, in the 3.46 Ga deep hot ocean that was influenced by hydrothermal activity. In the 3.2 Ga ocean, that was shown from our studies to have been very similar to the 3.46 Ga ocean, microbial denitrification, oxygenic photosynthesis, and sulfate reduction were all active. Our major conclusion is that the Mesoarchean ocean was generally oxic with local and temporal existence of anoxic water bodies. This study has far-reaching implications for the early co-evolution of microbial biosphere and surface environments of the Earth.
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