Occurrence characteristics and enrichment regularity of indium in pyrite: A case study of Dachang tin ore-field
(1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,
Ministry of Education, Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
3. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry,
Chinese Academy of Sciences, Guiyang 550002, China)
Ministry of Education, Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
3. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry,
Chinese Academy of Sciences, Guiyang 550002, China)
Abstract: To reveal the occurrence state and enrichment regularity of the dispersed element indium in pyrite, the petrology, mineralogy, geochemistry, and mineral physics were researched detailedly. The results suggest that the structure of pyrite is mainly composed of massive structure, disseminated structure, vein structure, reticular structure, comb structure and so on. Generally, the pyrite coexists with sphalerite, marmatite, pyrrhotite, chalcopyrite, galena, and arsenopyrite. And the texture of pyrite primarily consists of the metasomatic texture, solid solution texture, idiomorphic-hypidiomorphic granular texture, and disseminated texture. The content of indium in pyrite ranges from 0.491×10-6 to 65.1×10-6 with an average value of 14.38×10-6. Yet, the indium content in the Gaofeng deposit is higher than that in the Dafulou and Tongkeng deposit, showing a particularly significant supernormal enrichment. Besides, the cadmium content in pyrite is also higher than other dispersed elements, and similarly the abnormal enrichment of cadmium in the Gaofeng deposit is also very significant. An obvious positive correlation exists between In and Cd, or Tl, but a negative correlation between In and Re. It is difficult to find out a positive or negative correlation between In and Ga. The element zinc is of great importance to the enrichment of indium, which can possibly facilitate to the migration and crystallization of dispersed element indium.
Key words: dispersed element indium; pyrite; lattice structure; enrichment regularity; cassiterite-sulfide deposit; Dachang ore-field