2014 Fiscal Year Final Research Report
Iron and Oxygen Isotope Geochemistry of Lateritic Paleoweathering Profile in the Paleoproterozoic
| Project/Area Number |
24654164
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Geology
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| Research Institution | Toho University |
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Principal Investigator |
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| Project Period (FY) |
2012-04-01 – 2015-03-31
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| Keywords | ラテライト / 鉄 / 酸素 / 原生代 |
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| Outline of Final Research Achievements |
Based on the iron and oxygen isotope compositions of Paleoproterozoic lateritic weathering profile discovered in Botswana (Yamaguchi et al., 2007; EPSL), a significant negative correlation between iron and oxygen isotope compositions (the more severe/advanced the lateritization was, the more enriched in heavy iron isotope and the more depleted in heavy oxygen isotope the profile has) was discovered for the first time. Then, a numerical calculation suggests that the water-rock ratios for such lateritization would have been around 10,000~100,000 (similar to modern values), lateritization occurred in (sub)tropical environment in the past, and the oxygen isotope composition of seawater 2.2 billion years ago was 0 per mil.
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| Free Research Field |
アストロバイオロジー
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