In, Sn, Pb and Zn Contents and Their Relationships in Ore‐forming Fluids from Some In‐rich and In‐poor Deposits in China

Abstract: All the indium‐rich deposits with indium contents in ores more than 100times10−6 seems to be of cassiterite‐sulfide deposits or Sn‐bearing Pb‐Zn deposits, e.g., in the Dachang Sn deposit in Guangxi, the Dulong Sn‐Zn deposit in Yunnan, and the Meng'entaolegal Ag‐Pb‐Zn deposit in Inner Mongolia, the indium contents in ores range from 98times10−6 to 236times10−6 and show a good positive correlation with contents of zinc and tin, and their correlation coefficients are 0,8781 and 0.7430, respectively. The indium contents from such Sn‐poor deposits as the Fozichong Pb‐Zn deposit in Guangxi and the Huanren Pb‐Zn deposit in Liaoning are generally lower than 10times10−6, i.e., whether tin is present or not in a deposit implies the enrichment extent of indium in ores. Whether the In enrichment itself in the ore ‐forming fluids or the ore‐forming conditions has actually caused the enrichment/depletion of indium in the deposits? After studying the fluid inclusions in quartz crystallized at the main stage of mineralization of several In‐rich and In‐poor deposits in China, this paper analyzed the contents and studied the variation trend of In, Sn, Pb and Zn in the ore‐forming fluids. The results show that the contents of lead and zinc in the ore‐forming fluids of In‐rich and ‐poor deposits are at the same level, and the lead contents range from 22times10−6 to 81times10−6 and zinc from 164times10−6 to 309times10−6, while the contents of indium and tin in the ore‐forming fluids of In‐rich deposits are far higher than those of In‐poor deposits, with a difference of 1–2 orders of magnitude. Indium and tin contents in ore‐forming fluid of In‐rich deposits are 1.9times10−6‐4.1times10‐6 and 7times10−6‐55times10−6, and there is a very good positive correlation between the two elements, with a correlation coefficient of 0.9552. Indium and tin contents in ore‐forming fluid of In‐poor deposits are 0.03times10−6‐0.09times10−6 and 0.4times10−6‐2.0times10−6, respectively, and there is no apparent correlation between them. This indicates, on one hand, that In‐rich ore‐forming fluids are the material basis for the formation of In‐rich deposits, and, on the other hand, tin probably played a very important role in the transport and enrichment of indium.