| Project/Area Number |
02554028
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
鉱物学(含岩石・鉱床学)
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| Research Institution | Earthquake Research Institute, University of Tokyo |
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Principal Investigator |
KANEOKA Ichiro Earthquake Rersearch Institute, University of Tokyo, Professor, 地震研究所, 教授 (30011745)
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| Co-Investigator(Kenkyū-buntansha) |
瀧上 豊 関東学園大学, 法学部, 助教授 (40206909)
KANEOKA Ichiro Earthquake Research Institute, University of Tokyo, Professor (30011745)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥12,200,000 (Direct Cost: ¥12,200,000)
Fiscal Year 1991: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1990: ¥9,800,000 (Direct Cost: ¥9,800,000)
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| Keywords | Laser beam / Degassing / ^<40>Ar- ^<39>Ar dating / Argon gas / Minral / Mass spectrometer / アルゴンレ-ザ- / 四重極型質量分析計 / ^<40>Ar- ^<39>Ar年代測定 / レ-ザ-光 / 試料容器 / ^<40>Arー ^<39>Ar年代測定 / 希ガス抽出 / 岩石・鉱物 / 段階加熱 / 超高真空 |
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| Research Abstract |
The main aim in this study is to develop the ^<40>Ar- ^<39>Ar dating method by extracting Ar gases from a sample with the aid of a laser beam. Through this study, we have examined fundamental problems in extracting Ar gases from a mineral under different conditions and obtained a prospect that the ^<40>Ar- ^<39>Ar dating would be possible with the amount of extracted Ar gases by this method.
Through this study, it has been revealed that the efficiency of heating a sample with a laser beam is controlled by many factors such. as the concentration of a laser beam, an angle of incidence of a laser beam to the surface of the sample, the efficiency of used lenses, the out-put power of the laser generator and so on. To observe the condition of the surface of a sample, an optical microscope is efficient, but is not always compatible with the best condition for the laser irradiation. We are trying to using a video system to observe the sample during a laser irradiation. There remain some problems in future, among which the estimate of the temperature on the surface of a sample during a laser irradiation, the estimate of a volume of a fused part by a laser irradiation and the fusing of a high temperature felscic mineral are included. In addition, to date a young volcanic rock of less than 10Ma with this method, it is essential to use a high sensitive and precise mass spectrometer to measure the very small amount of Ar degassed by a laser beam from a sample.
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