在系统介绍洞穴石笋高精度ICP—MS铀系年代学原理与方法的基础上,对贵州荔波县衙门洞Y1石笋进行了ICP—MS ^230Th测年研究。综合分析认为精确时标的建立对于利用石笋进行古气候重建具有重要的实际意义;采用ICP—MS ^230Th测年方法进行石笋样品定年准确可靠,并且比TIMS方法具有更高的效率,所需样品更微量。通过生长速率变化分析表明,石笋生长速率记录了过去冷暖突变事件,因此可以用它作为一个有意义的环境记录替代指标来研究古降水及古气候变化。
Based on the introduction to high precision ICP-MS uranium series chronology mechanism and method, the stalagmite Y1 from Yamen cave, Libo county, Guizhou province, China was dated with the method in the paper. From researching on ^230Th data of stalagmite Y1, the following conclusions can be made. The precise chronology established is of practical significance for the reconstruction of paleo-climate by stalagmite; ICP-MS ^230Th dating method is accurate and credible, which is more efficient than TIMS method ; ICP-MS ^230Th dating method needs much less weight of calcite sample. By researching growth rate of stalagmites, it is proved that growth rate can record abrupt cold and warm events in the past global climatic changes. Therefore, growth rate of stalagmites could be regarded as a good environmental proxy for the study of Changes in paleo-precipitation and paleo-climate.