中文摘要：

湖泊沉积物是研究古气候、古环境的理想对象。本文选取鹤庆湖泊沉积物开展了样品BeO制备的实验研究。通过对比黄土提取10Be的思路，利用条件实验确定了先沉淀去除常量元素，再进行阳离子交换的新的实验流程。加速器质谱仪的测量结果表明该流程有效可靠，为下一步拓展湖泊10Be环境示踪的新方向提供了实验方法基础。

英文摘要：

Background, aim, and scope The cosmogenic radionuclide 10Be is produced primarily by nuclear interactions between secondary cosmic-ray particles with oxygen and nitrogen in the atmosphere. Its production rate is mainly regulated by the geomagnetic field intensity on time scales of thousands to hundreds of thousands years, so that its accumulated concentration in sediments can, in principle, be used to derive high-resolution records of geomagnetic field changes. A lot of researches that trace paleo- geomagnetic intensity variation using l~Be in ice core, lake and loess sediment were reported during recent years. The results have validated the l~Be technique using AMS, as a viable tool to trace past paleo- geomagnetic intensity changes. However, the research about 1~Be in lake sediment hasn＇t been reported in China. Therefore, it is very necessary to study the lacustrine sample, especially the chemical pretreatment method, which will provide the experimental foundation for environment tracing by lacustrine ~~Be. In this paper, we research the procedure of BeO preparation of samples from Heqing lake sediment. Materials and methods The Heqing Basin in Yunnan was the first deep drill core, which obtained about 666 m depth sediment. The sediment was mainly lacustrine. In the paper, we chose a small part of the drill core as our samples. The depth range of the samples is 120--180 m, the interval of which is 8 cm. According the procedure of BeO preparation of loess samples, it is an important step to create the leaching curve. The time scope of Be from the samples in loess and paleosol is the same. But according the result of condition experiment, the time range of Be of different lacustrine samples was different. Obviously, once cation exchange can not separate Be. So we tried twice cation exchange and precipitation-cation exchange respectively, in order to decide which one can separate Be. Results The experiment results show that （1） we collected the leachate between 800--3600 s. The solutions were evaporated and