石英中子活化微量稀土成分分析在解决金矿床成因及物质来源方面的应用

THE APPLICATION OF QUARTZ NEUTRON ACTIVATION TRACE REE ANALYSIS TO GENESIS AND MATERLAL SOURCE OF GOLD DEPOSIT

通过对五台地区高凡矿田高凡银金矿床中的脉石英、石英斑岩中的石英斑晶、铜钼矿化脉石英和变辉绿岩脉中脉石英的中子活化稀土成分分析,并结合苏联有关研究资料表明:石英中微量稀土元素的地球化学特征基本上反映了其形成时初始溶液或岩浆的稀土元素地球化学行为,可利用来判断金矿床的成因及成矿物质来源.浅成金矿床脉石英显示∑REE、∑Y/∑S_c、∑LREE/∑HREE、Eu/Sm较小,La/Yb处于地壳岩石计算值范围,稀土配分模式基本与酸性岩类的一致;深成金矿床脉石英则显示∑REE、∑Y/∑S_c、∑LREE/∑HREE、Eu/Sm较大,La/Yb低于地壳岩石计算值,稀土配分模式与超基性岩类相似.

After the neutron activation REE analysis for vein quartz, the phenocryst quartz in quartz porphyry, the Cu-Mo mineralized vein quartz and the vein quartz in metadiabase in Gaofan orefield Wutai district, and refering to some studies from Russia, it shows that the trace REE geochemical characteristics of quartz can basically represent the geochemical characteristics of the initial mineralizing solution or magma in which the quartz was formed, and can be used to determine the genesis and material source of gold deposit: In shallow-seated gold deposit, the quartz shows high ∑REE、∑Y/∑Sc、∑LREE/∑HREE, low Eu/Sm, La/Yb in the range of the earth crust rock, the REE pattern similar to that of the acid rocks; in deep-seated gold deposit, the vein quartz shows low ∑REE、∑Y/∑Sc、∑LLREE/∑HREE、 high Eu/Sm, La/Yb below the calculated value of the earth crust rock, and the REE pattern similar to that of the ultrabasic rocks.