Development of the ^<40>Ar- ^<39>Ar dating method based on the Ar extraction from a sample by using a laser beam.

开发基于使用激光束从样品中提取Ar的^ 40 Ar-^ 39 Ar测年方法。

• 批准号: 02554028
• 负责人: KANEOKA Ichiro
• 金额: $ 7.81万
• 依托单位: Earthquake Research Institute, University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02554028/
• 关键词: 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

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.

本研究的主要目的是发展^<40>Ar- ^<39>Ar定年方法，方法是在激光束的帮助下从样品中提取Ar气体。通过本研究，我们探讨了在不同条件下从矿物中提取氩气的基本问题，并展望了用该方法提取氩气的量可以实现^<40>Ar- ^<39>Ar定年。通过本研究，揭示了激光加热样品的效率受多种因素的控制。如激光束的浓度、激光束与样品表面的入射角、所用透镜的效率、激光发生器的输出功率等。为了观察样品的表面状况，光学显微镜是有效的，但并不总是与激光照射的最佳条件相兼容。我们正在尝试使用视频系统来观察激光照射过程中的样品。在今后的研究中还存在一些问题，其中包括激光辐照过程中样品表面温度的估计、激光辐照熔接件体积的估计和高温熔融矿物的熔接等。此外，要用这种方法测定小于10Ma的年轻火山岩的年代，必须使用高灵敏度和精确的质谱仪来测量样品中激光束脱气的极少量Ar。

项目成果

Kaneoka,I.: "Radiometric age and Sr isotope characteristics of volcanic rocks from the Japan Sea floor." Geochem.J.24. 7-19 (1990)

Kaneoka,I.：“日本海底火山岩的辐射年龄和 Sr 同位素特征。”

Kaneoka, I., Notsu, K., Takigami, Y., Fujioka, K., and Sakai, H.: "Constraints on the evolution of the Japan Sea based on ^<40>Ar- ^<39>Ar ages and Sr isotopic ratios for volcanic rocks of theYamato Sea-mount chain in the Japan Sea." Earth Planet. Sci. Le

Kaneoka, I.、Notsu, K.、Takigami, Y.、Fujioka, K. 和 Sakai, H.：“基于 ^<40>Ar- ^<39>Ar 年龄和日本海演化的约束

Kaneoka,I.: "Radiometric age and Sr isotope charateristics of volcanic rooks from the Japan Sea floor." Geochem.J.24,. 7-19 (1990)

Kaneoka,I.：“日本海底火山车的辐射年龄和 Sr 同位素特征。”

Kaneoka,I.and Takaoka,N.: "Evolution of the lithosphere and its interaction with the underlying mantle as inferred from noble gas isotopes." Australian Jour.Earth Sci.38. 559-567 (1991)

Kaneoka,I. 和 Takaoka,N.：“根据稀有气体同位素推断岩石圈的演化及其与底层地幔的相互作用。”

Takigami, Y. and Funaki, M.: " ^<40>Ar- ^<39>Ar and K-Ar ages for igneous and metaporphic rocks from the Sor Roundane Mountains, East Antarctia." Proc. NIPR Symp. Antarct. Geosci.35. 122-135 (1992)

Takigami, Y. 和 Funaki, M.：“南极洲东部 Sor Roundane 山脉的火成岩和变质岩的 ^<40>Ar- ^<39>Ar 和 K-Ar 年龄。”