1991 Fiscal Year Final Research Report Summary
Development of the ^<40>Ar- ^<39>Ar dating method based on the Ar extraction from a sample by using a laser beam.
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 |
Research Field |
鉱物学(含岩石・鉱床学)
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Research Institution | Earthquake Research Institute, University of Tokyo |
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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Keywords | Laser beam / Degassing / ^<40>Ar- ^<39>Ar dating / Argon gas / Minral / Mass spectrometer |
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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[Publications] Kaneoka,I.,Takigami,Y.,Takaoka,N.,Yamashita,S.and Tamai,K.: " ^<40>Ar- ^<39>Ar analyses of volcamic rocks recovered from the Japan Sea floor by Legs 127 and 128:Constraints on the age of formation of the Japan Sea." Tamaki,K.,Suyehiro,K.,Allan,J.,et al.,Proc.ODP.Sci.Results,128:College Station,TX(Ocean Drilling Program). (1992)
Description
「研究成果報告書概要(和文)」より
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[Publications] Kaneoka, I., Takigami, Y., Takaoka, N., Yamashita, S. and Tamaki, K.: " ^<40>Ar- ^<39>Ar analyses of volcanic rocks recovered from the Japan Sea floor by Legs 127 and 128 : constraints on the age of formation of the Japan Sea." Tamaki, K., Suyehiro, K., Allan, J. et al., Proc. ODP. Sci. Results, 128 : College Station, TX (Ocean Drilling Program). (1992)
Description
「研究成果報告書概要(欧文)」より
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