Indium Mineralization in the Y ejiwei S n‐Polymetallic Deposit of the S hizhuyuan Orefield, S outhern H unan, C hina

The Y ejiwei deposit, which is located in the southern H unan W – Sn – Pb – Z n M etallogenic B elt in south C hina, is a large‐scale porphyry–skarn–veinlet‐type deposit containing 806 t I n. M ineralization occurs as porphyry‐type S n (stockworks), skarn‐type S n– C u, marble‐hosted‐type S n– C u (veinlet), and vein‐type P b– Z n ores. Thirty‐five ore samples were collected from the Y ejiwei deposit for bulk and mineral chemical composition, microscopic observation and electron microprobe analyses. The porphyry‐type S n ores contain variable amounts of I n (2.3–76 ppm; mean of 17.4 ppm) with local I n enrichment (226 ppm) and 1000 ×  I n/ Z n values are 3.8–52.4. The skarn‐type C u– S n ore is richest in I n (12.3–214 ppm; mean of 114 ppm), and 1000 ×  I n/ Z n values are 2.4–117. In contrast, the In content of the marble‐hosted‐type C u– S n ores is relatively low (7.4–34.9 ppm; mean of 20.3 ppm), and 1000 ×  I n/ Z n is in the range of 0.61–5.5, and the vein‐type P b– Z n ores in the external zone contain the lowest I n contents (7.2–17.0 ppm; mean of 12.1 ppm) with 1000 ×  I n/ Z n values of 0.07–0.09. The ore minerals in the deposit include pyrite, pyrrhotite, cassiterite, and I n‐bearing minerals of sphalerite, chalcopyrite, and stannite. Although only trace amounts of sphalerite are hosted in the porphyry ores, the sphalerite contains the highest I n content (0.27–10.1 wt.% I n) in the deposit. We observed the highest I n contents of all I n‐bearing sphalerite reported in C hina. The I n contents of sphalerite in the skarn‐type ore range from 0.15 to 0.56 wt.%, whereas the marble‐hosted‐, and vein‐type ores have lower I n contents (0.00–0.04, and 0.03–0.06 wt.%, respectively). The In resources of the Y ejiwei deposit are mainly hosted in skarn ores of the No. 31 and No. 32 orebodies. The genesis of I n in the Y ejiwei deposit was closely related to the shallow intrusive environment of related igneous rocks. As W – S n– M o– B i– C u– P b– Z n– A g mineralization is widespread in south H unan, this study would suggest a focus on skarn‐type S n– Z n deposits for the future prospecting of I n resources.