年轻沉积物^(36)Cl测年研究进展

Progress in ^(36)Cl Dating of Young Sediments

宇宙成因核素36Cl对第四纪地层及第四纪时代的厘定具有独特的优势。近年来随着加速器质谱(AMS)技术的不断发展,36Cl已经能被高灵敏测量,使得36Cl测年技术前景广阔。本文介绍了36Cl测年的研究现状和研究难点,对于陆相沉积物的36Cl测年方法进行了探索,对制约其发展的测年公式中早期放射性比度I0对测年精度的影响以及在地球科学中的应用前景进行了探讨,进一步提出不同海拔高度对I0存在叠加效应。同时介绍了36Cl样品的制备流程,该流程采用离子交换树脂驱除试样中的硫和可能产生"盐效应"的常量金属元素,有效地排除了36S对36Cl的干扰,建立了动态的AgCl制样技术流程,方法高效快捷。

The cosmogenic ^36Cl has a unique advantage for the dating of quaternary strata and the quaternary period. Due to the continuous development of Accelerator Mass Spectrometry （AMS） , ^36Cl can now be measured to a high degree of sensitivity. The research status and difficulties surrounding the use of ^36Cl as a dating tool are discussed, especially the dating method in continental sediments. The early specific activity I0 in the dating formula which restricts the application of this technique is also discussed including the theory that the superimposition effect has to I0 at different elevations. The process of the sample＇s preparation is also introduced as a dynamic AgCl sample preparation process, namely that the ion exchange resin is applied to remove S and the metallic elements which maybe produce the ‘salt effect＇ , effectively eliminate the interference to ^36Cl by ^36S. This method has the advantage of being very efficient.