The Maliping large-scale Pb-Zn deposit is located in the Sichuan-Yunnan-Guizhou Pb-Zn polymetallic metallogenic triangle area (SYGT), where the Pb-Zn ore body is hosted in the interlayer fracture zone at the interface between siliceous cataclastic dolomite and clastic rocks in the Lower Cambrian Yuhucun Formation and is tectonically driven. Unlike other Pb-Zn deposits hosted in the Sinian and Carboniferous carbonate rocks in the area, the metallogenic mechanism and deep and peripheral ore prospecting prediction research require further exploration. In this study, representative samples of a typical orebody profile were systematically collected, and microthermometry of fluid inclusions and H-O isotopes and metal sulfide trace element analyses were performed. The main findings were as follows: (1) The fluid inclusion study showed that the ore-forming fluids have vapor-rich phase reduction characteristics of medium-low temperature, salinity, and density. (2) H-O isotopic studies showed that the ore-forming fluids are derived from the mixing of deep-source fluids flowing through the deep fold basement (Kunyang Group) and organic containing basin brine. (3) Rare earth element (REE) characteristics indicate that the ore-forming materials were primarily derived from the folded basement (Kunyang Group). (4) The trace element study showed that sphalerite is relatively enriched in Cu, Cd, Ga, and Ge, while depleted in Fe, Mn, Sn, and Co, similar to the typical Huize-type (HZT) Pb-Zn deposit in the area. Therefore, it is suitable to explore the deposit using a large-scale “four step style” ore prospecting method for ore prospecting and prediction. Moreover, the results provide a reference for the study of Pb-Zn metallogenic systems and new ideas for the deep and peripheral prospecting of Pb-Zn deposits in this area.

The Malongchang Ag-Pb polymetallic deposit is located at the junction of the eastern part of the Tethys mega-tectonic domain and the southwestern margin of the Yangtze Craton. It is a medium-sized Ag-dominant deposit (300 tons of proven Ag metal reserves) associated with Pb, Cu, and Zn and has considerable exploration potential, but its theoretical research and level of exploration remain poorly constrained. Based on systematic in-situ trace element and S-Pb isotope analyses, the following conclusions were drawn: (1) The δ³⁴S values range from − 8.44‰ to 3.51‰, with a mean of approximately − 2.47‰, indicating enrichment in light sulphur isotopes. The reduced S is of crustal origin and mainly derived from the thermochemical reduction of sulphate in basin brine. (2) Ore-forming metal materials are sourced primarily from the Kunyang Group folded basement and partially provided by fluids extracting ore-forming materials from the wall rock. (3) Ag occurs mainly in galena. Sphalerite is enriched in Cd and Hg and depleted in Mn, Fe, Co, In, and Sn, similar to the Mississippi Valley-type deposits. (4) The ore-forming formation, resulted from the sequential migration of two fluids and subsequent mixed-fluid precipitation. These findings provide theoretical support and new guidance for prospecting in the deeper and peripheral parts of the Malongchang deposit, and the larger Ag-Pb polymetallic metallogenic region.