26Al/10Be等时线埋藏测年法基本原理与应用简介

Introduction to Basic Principles and Applications of Isochron 26Al/10Be Burial Dating Method

中文关键词:  26Al/10Be埋藏测年  等时线  继承核素  浓度剖面模型

英文关键词:26Al/10Be burial dating  Isochron  Inherited nuclide  Depth profile

中文摘要:

      介绍了26Al/10Be等时线埋藏测年法的基本原理及英主要应用范围.将应被同时埋藏的一组石英矿物样的26Al-10Be浓度拟合成等时线,从其斜率解得样品的埋藏年代.在如下情况下该法可克服未知参数多于制约方程的困难:1)冰碛物-古土壤序列中古土壤形成年代的研究,以规避继承核素(inherited nuclide)的干扰；2)因样品埋藏不够深引起的后期生成核素的干扰.此外,依据等时线拟合结果可判断样品是否符合简单恒态侵蚀模式.等时线法的引入,拓宽了埋藏测年的应用范围,并为埋藏测年数据可信度提供了一种有效的验证手段.

英文摘要:

      This paper introduces the basic principles of isochron 26Al/10Be burial dating.The 26Al-10Be concentrations of a set of coeval quartz samples may be grouped into a straight line by using least squares fitting.Then the samples’ burial age can be calculated from the slope of the obtained isochron.In the following two cases,the isochron burial dating can address the issues where unknown parameters outnumber constraint equations:1.the dating of paleosol formation in a sequence of intercalated tills and paleosols to circumvent the presence of unknown 26Al/10Be inherited from past exposure.2.the dating of samples with posteriorly produced cosmogenic nuclides due to insufficient shielding.Besides,according to the result of linear fit,whether or not the samples conform to the "simple steady-state erosion model" can be verified.The establishment of isochron method broadens the application range of burial dating.Moreover,this approach can provide an effective means to check the reliability of burial ages.