LA–ICP–MS analysis of sulfides from the Jianzhupo deposit, Guangxi Province, China: Insights into element incorporation mechanisms and ore genesis

Abstract

The Jianzhupo deposit, the largest Zn-Sb deposit in the Wuxu orefield in China, contains abundant sphalerite and jamesonite, contrasting with typical Sb deposits elsewhere. Whether the Sb and Zn in the deposit derived from similar parental sources is not clearly resolved. Here, trace-element compositions of sulfides from the deposit were determined by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). Results indicate that jamesonite is an important Cd-bearing sulfide with Cd contents of 523–764 ppm and minor or no significant Cd variations were observed within jamesonite crystals. Trace-element compositions of jamesonite indicates that Cd enters the lattice by coupled substitution as 2Fe2+ ↔ Zn2+ + Cd2+. Due to similar geochemical behaviors between Zn and Cd in hydrothermal systems, Zn/Cd ratio of sphalerite was suggested as a robust geochemical tracer to distinguish metal sources in such systems. Here, we summarized the Zn/Cd ratios of sphalerite from various hydrothermal systems and the results show that values between 169 and 233, and lower than 44 are from high- and low-temperature temperature fluid conditions, respectively. Due to different Zn/Cd ratios between sediments and igneous rocks, we conclude that metals in sphalerite from the Jianzhupo deposit were likely derived from granite; in contrast, metals in jamesonite were related to sedimentary rocks. These conclusions are consistent with previous studies on the deposit. Overall, our results indicate that ore-forming fluids of the Jianzhupo deposit were derived from magmatic–hydrothermal and basin water. This study extends the application of trace-element compositions in resolving the sources of sulfides in hydrothermal systems.