| Project/Area Number |
15340168
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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 |
Geology
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| Research Institution | Shinshu University |
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Principal Investigator |
KUMON Fujio Shinshu University, Fac.Science, Dept.Environmental Sciences, Professor, 理学部, 教授 (60161717)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAKE Yasuyuki Shinshu University, Fac.Science, Dept.Geology, Professor, 理学部, 教授 (70200144)
FUKUSHIMA Kazuo Shinshu University, Fac.Science, Dept.Environmental Sciences, Professor, 理学部, 教授 (20106602)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥15,900,000 (Direct Cost: ¥15,900,000)
Fiscal Year 2005: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2004: ¥5,300,000 (Direct Cost: ¥5,300,000)
Fiscal Year 2003: ¥8,000,000 (Direct Cost: ¥8,000,000)
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| Keywords | Paleoclimate / Takano Formation / total organic carbon / glacial age / Lake Nojiri / pollen analysis / marker tephra / MIS 5 / 気候変動 / 氷期 / 間氷期 / MIS 5 / 古環境 / 有機炭素含有率 / MIS3 |
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| Research Abstract |
The paleoclimate during the last 60,000 years have been reconstructed in detail, based on the drilled lake sediments from Lake Nojiri. Total organic carbon (TOC) and total nitrogen (TN) are used as new excellent proxies of paleoclimate as well as pollen analysis data. These data have about 50 years interval in average, and can provide one of standard climate changes around East Asia in the Last Glacial and Post-glacial periods.
The drilled sediments of Takano Formation in Nagano City, 54.5 meters long, is composed of homogenous silty clay, and are intercalated with many tephra layers. Radiometric ages of several wide-spread marker tephras offers keys of age estimation of sediments. TOC and TN contents are measured in 1cm interval, about 26 years average. The vertical profile of TOC and TN contents varies concordantly with marine ^<18>O isotope curve and also with ^<18>O isotope curve of Greenland ice cores from 160,000 years to 40,000 years age. This result is the first detailed reconstruction of paleoclimate of Japanese land area.
These reconstructions are one of best paleoclimate data in and around Japan in time resolution and long coverage. These data can be a standard of paleoclimate in Japan, because they can be correlated with other areas by the means of marker tephra.
On the other hand, we have tried to clarify the process how TOC and TN contents in lake sediments reflect climate change. The modern relationship among TOC contents in sediment, biological productivity of lake water and weather factors in Lake Kizaki, central Japan were examined from 1982 to 2002. The study have revealed that winter temperature which means duration of cold season, control annual biological productivity in lake water, resulting in the amount of accumulated organic matters.
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