| Project/Area Number |
08409001
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
広領域
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
TOYODA Kazuhiro Hokkaido Univ., Graduate school of Environmental Earth Science, Asso.Pro., 大学院・地球環境科学研究科, 助教授 (10207649)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Shunitsu Hokkaido Univ., Graduate school of Environmental Earth Science, Pro., 大学院・地球環境科学研究科, 教授 (30142194)
HASEBE Kiyoshi Hokkaido Univ., Graduate school of Environmental Earth Science, Pro., 大学院・地球環境科学研究科, 教授 (70000859)
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| Project Period (FY) |
1996 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥18,400,000 (Direct Cost: ¥18,400,000)
Fiscal Year 1999: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1998: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1997: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1996: ¥13,600,000 (Direct Cost: ¥13,600,000)
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| Keywords | paleo-environmental change / Lake Biwa / core sediment sample / paleo-water depth / eolian dust / Arsenic / ICP-AES / INAA / ピストンコア / ピストン・コア / ICP 発光分析 |
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| Research Abstract |
We performed both neutron activation analysis and ICP-AES of sediments taken from the 250 m thick top bed of Lake Biwa at 1.4-2 m intervals, three ca.10 meter long piston cores at 6cm intervals, varved core from the center of Lake Suigetsu at 2 cm intervals during the last glacial/Holocene transition, and the samples from surface sediments and from land around Lake Biwa and Lake Suigetsu for the comparison. The goals in this study are three : (1) Evaluation of As contents as the geochemical proxy of paleo-water-depth ; (2) Quest of geochemical proxy for synchronisation with glacial/-interglacial climatic changes and rapid climatic change ; (3) Research of the relationship between the geochemical change and tectonic movements around the cores. The research results are as follows : (1) Arsenic content is invalid for the accurate proxy of paleo-water-depth. Alternatively, the amount of lepidochrosite is hopeful. (2) The time series of Th/Sc ratios in top bed of Lake Biwa is synchronized with climatic changes and also correlated with the reported aeolian dust flux. While, we cannot detect the change of Th/Sc ratios at the last glacial/Holocene transition from the ca.10m poison cores. We found the times of great precipitation from the core of Lake Suigetsu. (3) We can detect the chemical variation as the result of tectonic movement around Lakes successfully.
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