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。

基本信息

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

项目摘要

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.

这项研究的主要目的是通过借助激光束从样品中提取AR气体来开发 ^<40> ar- ^<39> AR定型方法。通过这项研究，我们研究了在不同条件下从矿物质中提取AR气体的基本问题，并获得了一种前景，即通过此方法，通过此方法，通过此研究的提取的AR气体量可能会出现 ^<40> ar- ^<39> AR的预期。已经显示，通过许多因素，通过激光束来控制样品的效率。作为激光束的浓度，激光束与样品表面的发射角，用过的镜头的效率，激光发电机的额外功率等。为了观察样品表面的状况，光学显微镜是有效的，但并不总是与激光照射的最佳条件兼容。我们正在尝试使用视频系统在激光照射期间观察样品。将来仍然存在一些问题，其中包括激光照射期间样品表面上温度的估计值，包括激光照射通过激光辐射的融合部分的估计值以及高温Felscic矿物质的融合。此外，迄今为止，使用这种方法，年轻的火山岩小于10mA，必须使用高灵敏和精确的质谱仪来测量样品中激光束的脱水量很少。