| Project/Area Number |
14390056
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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 |
広領域
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| Research Institution | National institute of Polar Research |
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Principal Investigator |
MIURA Hideki Natianal Institute of Polar Research, Division for Research and Education, Research Associate, 研究教育系, 助手 (10271496)
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| Co-Investigator(Kenkyū-buntansha) |
OHKOCHI Naohiko Japan Agency for Marine-Earth Science and Technology, Group Leader, 地球内部変動研究センター, グループリーダー (00281832)
YOKOYAMA Yusuke The University of Tokyo, Lecture, 大学院・理学研究科, 講師 (10359648)
MORIWAKI Kiichi National institute of Polar Research, Division for Researrh and Education, Professor, 研究教育系, 教授 (50033501)
五十嵐 厚夫 東京大学, 海洋研究所, 海洋科学特定共同研究員
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥13,400,000 (Direct Cost: ¥13,400,000)
Fiscal Year 2004: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2003: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2002: ¥8,900,000 (Direct Cost: ¥8,900,000)
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| Keywords | Antarctic ocean / Antarctic Ice sheet / marine sediments / ice melting water / fatty acid / sea-level changes / ice rafted debris / climatic change / 南極海海底堆積物コア / 海洋プランクトン / 脂肪酸 / 放射性14C年代 / 水素同位体比 / 珪藻化石 / 有孔虫化石 / 宇宙線生成核種 |
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| Research Abstract |
We have measured the radiocarbon and hydrogen isotope contents of individual, solvent-extractable, short-chain (C14, C16, and C18) fatty acids isolated from Ross Sea surface sediments. The corresponding 14C ages are equivalent to that of the post-bomb dissolved inorganic carbon (DIC) reservoir. Moreover, molecular 14C variations in surficial (upper 15 cm) sediments indicate that these compounds may prove useful for reconstructing chronologies of Antarctic margin sediments containing uncertain(and potentially variable) quantities of relict organic carbon. A preliminary molecular 14C chronology suggests that the accumulation rate of relict organic matter has not changed during the last 500 14C yr. The focus of this study is to determine the validity of compound-specific 14C and hydrogen isotope analysis as a technique for reconstructing chronologies of Antarctic ice melting events.
Furthermore, we studied 3 sediment cores recovered from off Antarctic Peninsula to reconstruct the melting h
… More
istory of the Antarctic Ice sheet during the last 24 kyrs. Rafted Debris (IRD) and terriginous material from the Antarctic Continent were investigated throughout the cores to obtain the timing and the magnitude of the melting events.- We employed the proxy to understand the origin of the sediments using the relative abundances of K2O and Na2O. -Surface sediments K2O/Na2O ratio correlated with the the degree of the influence from 3 surface currents in the region and hence the ratio can constrain the source area of the sediments. Chronologies of these cores were constructed based on both radiocarbon dating of sedimentary organic carbon and the relative abundance of radiolaria Cycladophora davisiana. Analyzing IRD, K2O/Na2O ratio, 14C and radiolaria in the cores showed temporal variations of IRD flux as well as the source regions of the sediment supply during the LGM to the present. IRD maxima were observed in 25-17 and 15-12 ka that show the considerable expansion of the ice sheet during the, LGM and rapid melting of the ice sheet at the time of the global melt water pulse la event respectively. Less
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