Organic Materials and Their Effects on Lead–Zinc Mineralization in the Xicheng Belt, Western Qinling (China): A Review

Xicheng is an important Chinese area enriched in lead–zinc polymetallic ore concentration area. Since the 1970s, substantial research achievements have been made in various domains, including the geological and geochemical characteristics of the deposits, metallogenic chronology, features of the marine basin during the initial mineralization stage, enrichment and precipitation of lead–zinc and other metallic ions, ore genesis, and metallogenic simulation experiments. Among these, the most representative findings focus on exhalative sedimentary reformation and the complexation of organic matter with lead–zinc metal elements during sedimentary processes. This review discusses the formation and evolution of sulfur-containing organic matter, especially H2S, under Thermal Decomposition of Sulfate (TDS), Bacterial Sulfate Reduction (BSR), and Thermochemical Sulfate Reduction (TSR) conditions, and further summarizes the general characteristics of organic matter and lead–zinc (and other metal elements) adsorption–complexation–reduction. Subsequent research on organic lead–zinc mineralization in the Xicheng area has been grounded in ore deposit geology and geochemistry, adopting the perspective of organic fluids. These studies focus particularly on the formation process of Pb–Zn organic complexes and analyze the various stages and mechanisms of mineralization based on the characteristics and evolution of organic matter. This approach provides new insights for understanding both the general features and the unique attributes of lead–zinc mineralization in the Xicheng area.