富铟及贫铟矿床成矿流体中铟与锡铅锌的关系研究

Relationships between indium and tin, zinc and lead in ore-forming fluid from the indium-rich and -poor deposits in China

富铟矿床几乎是锡石-硫化物矿床或富含Sn(Sn以硫盐类矿物存在或赋存于方铅矿等硫化物中)的CuP-b-Zn矿床。Sn的存在与否在某种程度上意味着In的富集与否。以富铟与贫铟矿床主成矿期石英中的流体包裹体为研究对象,分析了成矿流体中In、Sn、Pb和Zn的含量,结果显示,两类矿床成矿流体中Pb和Zn的含量处于同一水平,而富铟矿床成矿流体中In和Sn的含量远远高于贫铟矿床,二者相差1～2个数量级。这一方面说明富铟的成矿流体是形成富铟矿床的物质基础,另一方面说明Sn在In的迁移富集过程中起着重要作用。

In China, indium-rich deposits are almost the cassiterite-sulfide or tin-bearing Cu-Zn-Pb sulfide deposits. That is to say, enrichment of indium in one deposit depends on whether tin exists to a certain extent. In order to find out relationship between tin and indium, the fluid inclusions in quartz from some indium-rich and -poor deposits in China are taken as ore-forming fluid and contents of In, Sn, Zn and Pb are analyzed by ICP-MS in this paper. The result shows that contents of Pb and Zn in the ore-forming fluid from the two types of deposits are uniform, their range is from 31 to 74 μg/g for Pb and 164 to 221 μg/g for Zn, while contents of In and Sn in ore-forming fluid from the indium-rich deposits, which are from 2.5 to 4.1 μg/g for In and from 15 to 39 μg/g for Sn, are largely higher than those from the indium-poor deposits, which are from 0.03 to 0. 09 μg/g for In and from 0.4 to 2 μg/g for Sn. These characteristics indicate that indium-rich ore-forming fluid is the material foundation for formation of the indium-rich deposit, and element tin probably plays an important role in the processes of the indium activation, transference and enrichment.