裂变径迹LA-ICP-MS/FT法原理、实验流程和应用

PRINCIPLE,EXPERIMENTAL PROCESS AND APPLICATION OF FISSION TRACK LA-ICP-MS/FT METHOD

裂变径迹是一种重要的低温热年代学测年方法,目前被广泛应用于岩体冷却年龄测试及各种构造演化热历史等的研究.该方法主要包括传统的外探测器法和近年来新开发的激光-电感耦合等离子质谱法(LA-ICP-MS/FT).由于传统的外探测器法一直受限于国内反应堆中子热化不充分、辐照周期长以及辐照带来的环境安全等问题,无法有效、快速地获得数据.相反,LA-ICP-MS/FT法的建立和应用不仅避免了因中子热化不充分、热中子分布不均带入的误差而提高了测年精度,而且还极大地提高了测试效率,缩短了解决科学问题的时间.通过对近年来新建立的裂变径迹LA-ICP-MS/FT法的测年基本原理和方法、实验步骤、常用年龄值和裂变径迹退火等的详细介绍,综述了该方法在相关应用方面的研究进展,并与传统的外探测器法进行了详细的对比.最后综述了LA-ICP-MS/FT法在造山带冷却隆升历史、沉积盆地分析、盆-山耦合系统分析、断裂活动、成矿时代和矿体保存等多方面的应用.

Fission track,an important low-temperature thermochronology dating method,is widely used in rock mass cooling age tests and study of thermal history of tectonic evolution.It mainly includes the traditional external detector(EPMA)method and newly-developed LA-ICP-MS/FT method.Due to the limitations of traditional method,such as inadequate neutron thermalization in domestic reactors,long irradiation period and environmental security problems,data cannot be obtained effectively and quickly.On the contrary,the establishment and application of LA-ICP-MS/FT not only avoids the errors caused by inadequate neutron thermalization and uneven thermal neutron distribution,but also greatly improves the testing efficiency and shortens the time to solve scientific problems.Through the detailed introduction to fission track LA-ICP-MS/FT dating principle and method,experimental process,commonly-used age value and fission track annealing,the paper discusses the research progress of the method in related applications and compares with traditional external detector method,and finally summarizes the applications in analyses of cooling and uplift history of orogenic belts,sedimentary basins,basin-mountain coupling system,fault activities,metallogenic age and orebody preservation.