稀有气体同位素测试技术及其在矿床学研究中的应用

Noble Gas Isotope Analytical Techniques and Its Application in Economic Geology Researches

稀有气体包含He、Ne、Ar、Kr、Xe、Rn六种元素,由于其化学性质十分的稳定,一般不参与各种化学反应过程。其在地球不同圈层及地外物质中的丰度和同位素组成差别巨大,是地球科学研究的重要示踪剂。稀有气体同位素组成的测试方法主要有分阶段加热熔融、真空压碎、激光微区熔蚀等气体采集方式,获得的气体经多级纯化后在静态稀有气体同位素质谱中进行测试。在矿床学研究中,作为灵敏示踪剂的稀有气体同位素大多用于判别成矿物质、成矿流体的来源,特别是幔源物质的贡献大小及壳幔相互作用与成矿的关系,用于揭示矿床在成矿各阶段(期)中的物质和流体源区差异,用以追踪和揭示成矿流体的演化、反演成矿过程并在一定程度上指示成矿流体在成矿过程中的行为。稀有气体同位素为精细成矿作用研究、不同矿种成矿作用差异分析、探寻大规模成矿作用提供了重要的科研手段。

The noble gas contains six elements He, Ne, Ar, Kr, Xe, Rn, because of its chemical properties is very stable, generally do not participate in chemical reaction process. The noble gas in different earth spheres and extraterrestrial materials has a huge different abundance and isotope characteristic, and is one important tracer in earth science researches. Analytical techniques of noble gas isotopic composition has three methods for the gas collection, i. e. stepped heating, in vacuo crushing and laser micro zone ablation. The obtained gases will go through multi-stage purify system, and finally are tested by static noble gas isotope mass spectrometry. As the sensitive tracer, noble gas isotope can be used to identify the source of ore-forming materials and fluids, especially for the mantle original contribution, crust-mantle interaction and metallogenic relationship, in economic geological researches. It can be used to trace and reveal the differences among the ore-forming stages and the evolution of fluids and mineralizations. In addition, noble gas isotope also can indicate the behavior of fluid in ore-forming processes. Noble gas isotope provides an important scientific research tool for detailed mineralization study, metallogenic difference research and large-scale mineralization exploring.