210Pb测年方法在岩溶碳酸盐沉积物中的应用研究

碳酸盐沉积物中的210Pb,通过大气降水、土壤水渗入沉积物中吸附所得,并且不同沉积物组分和粒级对210Pb的吸附能力不同.笔者以沉积环境稳定、沉积的连续性及其剖面保存的完整性的洞穴沉积物--石笋和流石等作为主要研究对象,并与取自云南白水台的钙华样品进行210Pb的对比.利用210Ph测年技术方法对岩溶地区不同类型的近代碳酸盐沉积物样品进行测定,并探讨该方法适应范围.结果发现:利用210Pb法能够比较可靠的测定沉积物的沉积速率,并根据沉积物的相对垂直深度和210Pb比度的关系,计算出近100 a沉积物年龄和沉积速率.由此可见,210Pb测年技术在岩溶沉积物中的应用,将有助于获取高分辨率的计年,并提供精确的沉积速率,为现代岩溶作用过程的研究提供重要的信息,从而具有广泛的应用前景.

Application of 210Pb Dating Technique to the Study of Carbonate Sediments in the Karst Area

210Pb in carbonate sediments is derived from granule adsorption through the water cycle in soil and atmosphere.Moreover,different granules have different capabilities for the adsorption of 210Pb.The processes can be analyzed according to the 210Pb content.Using the 210Pb technique,the authors studied different modern carbonate sediments in different karst areas.The results show that the 210Pb technique can be reliably used to determine the velocity of carbonate sedimentation and calculate the time and velocity of carbonate sedimentation in the last 100 years through the study of the relationship between the depth of sediments and the ratio of 210Pb.It is concluded that the 210Pb technique can not only provide a means for studying carbonate sediments but also supply important information for modern karst development.