Metallogenesis and Formation of the Maliping Pb-Zn Deposit in Northeastern Yunnan: Constraints from H-O Isotopes, Fluid Inclusions, and Trace Elements

Abstract

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 Yuhuchun Formation and is tectonically driven. Unlike other Pb-Zn de-posits 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 or-ganic-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.

Editorial for Special Issue “Genesis and Evolution of Pb-Zn-Ag Polymetallic Deposits”

“…The fluid inclusion and H-O-He-Ar isotopic data suggests that ore-forming fluids in the Maoping deposit are the result of mixing of metamorphic fluids from the Precambrian basement and basinal brines from the Youjiang Basin [6]. Similarly, the new data from the Maliping deposit suggest that the ore-forming fluids are derived from the mixing of deep sourced fluids flowing through the basement and organic-bearing basinal brines [7].…”

Metallogenic Model for Pb-Zn Deposits in Clastic Rocks of the Dahai Mining Area, Northeast Yunnan: Evidence from H-O-S-Sr-Pb Isotopes

“…Studies on fluid inclusions in sphalerite and gangue minerals of several major deposits in the SYGT have shown that the homogenization temperature of the inclusions ranges from 115 to 280 • C, with an average range of 150-250 • C [17,18]. The average homogenization temperature of fluid inclusions from the Maliping deposit is 255 • C [19]. At this temperature, TSR may be the main mechanism responsible for the transformation of SO 4 2− into H 2 S in the hydrothermal solution.…”