Mississippi Valley Type (MVT)¹ deposits represent the majority of carbonate-hosted Zn–Pb deposits globally. They typically form in an extensional tectonic setting along passive margins. However, studies on carbonate-hosted Zn–Pb deposits in the Sichuan–Yunnan–Guizhou Triangle area (SYGT) reveal differences in terms of the essential features of typical MVT deposits. We discuss the main features of these deposits, controlled by folds and faults, high-grade Zn–Pb ores and symbiotic or associated elements (i.e., abundant Ag and dispersed amounts of Ge, Ga, and Cd) of significant economic value. Based on a comparison of Pb-Zn deposits in SYGT and classical MVT deposits formed in an extensional tectonic setting, as well as a subsequent discussion on deposit classification, we propose that the Huize-style Zn–Pb deposits are a new deposit style, whose basic features can guide future ore exploration. We define the Huize-style deposits based on four factors: i) Hierarchical ore-controlling system of strike-slip fault-fold structures, ii) litho-facies associated with typical alternation and mineralisation, iii) ore-forming geochemical features revealed by typical mineral assemblages, mineralisation alteration zoning, fluid-inclusion, isotope geochemistry and metallogenic acid–alkali geochemical barriers, and iv) different prospecting methods to those typically used for MVT deposits. The Huize-style and typical MVT deposits constitute the carbonate-hosted non-magmatic epigenetic hydrothermal-type (CNHT) Zn–Pb deposits.

1. Driving intention, characterized by ambiguity, dynamism, and unpredictability, necessitates implementing human-like thinking and effective driving intention prediction as pivotal steps toward fu...

Understanding the contamination and sources of heavy metal(loid)s (HMs) at historical sites is vital for safeguarding human health and the ecological environment. This study focused on As, Hg, Cd, Cu, Pb, Ni, and Cr concentrations in the residual soil, groundwater, and surface water around a mineral processing plant. The sources of these elements and the human health risks posed by them were evaluated using various indexes. Soil HM concentrations exceeded background values for Yunnan Province, ranked as As > Pb > Cd > Cu > Hg > Ni. The river water met China’s Class II waterbody standard; however, Cd, Cu, Pb, and pH exceeded the maximum permissible sewage discharge concentrations in the accumulated water. The groundwater showed severe HM pollution, meeting China’s Class III water quality standard. The average value of the Nemerow pollution index was consistent with that of the single-factor pollution index in the following order: As > Pb > Cd > Ni > Cu > Hg. Children face heightened risk through the oral ingestion of As, Cd, and Pb, particularly in high-value sampling points in the residue deposit area. The main sources of these pollutants are anthropogenic activities and the soil formation matrix.

This work investigates the ultra-large Huize Pb–Zn deposit, based on the results of preceding studies and detailed field geological surveys. The existing findings were reorganized and reinterpreted and supplemented with C–H–O isotopic measurements, which resulted in the identification of two different metallogenic fluids: a high temperature, low salinity, and acidic Fluid A, which originates from deep-seated fluids and is enriched in lighter C and O isotopes (−3‰<δ¹³C‰< −4‰; 10‰<δ¹⁸O‰< 17‰; −92‰<δD‰< −50‰), and a low temperature, high salinity Fluid B, which is a subsurface brine formed by atmospheric precipitation. Fluid B is characterized by heavier C–O–H isotopic compositions (−2‰<δ¹³C‰< 1‰; 2‰<δ¹⁸O‰< 24‰; −66‰<δD‰< −43‰) than Fluid A and cycles continuously within the strata. We hypothesize that the Huize Pb–Zn deposit is the result of large-scale fluid migration from deep regions of the crust. These upward-moving fluids extracted metallic elements from carbonate strata of various ages, forming a metal-rich metallogenic fluid (Fluid A). After higher-grade ores were precipitated from the fluid following decompression boiling, it then mixed with Fluid B and continued to precipitate sulfides.

Germanium (Ge), as a critical metal, is in high demand due to its growing usage in emerging industries and green technologies. The Sichuan-Yunnan-Guizhou Zn-Pb metallogenic region, located on the southwestern margin of the Yangtze block, is one of the most important producers of Ge in China. The Maoping Zn-Pb deposit in the Sichuan-Yunnan-Guizhou region contains Ge-bearing sphalerite, whose crystal chemistry and process of Ge incorporation are poorly resolved. Sphalerite occurring in two hydrothermal stages (Sp-II and Sp-III) is recognized in this deposit. Laser ablation inductively coupled plasma mass spectrometry was used to map the concentrations of key elements (including Mn, Fe, Cu, Ga, Ge, As, Ag, Cd, In, Sn, Sb, Hg, and Pb) in Sp-II and Sp-III, and their distributions were qualitatively compared, followed by a quantitative assessment through application of the structural similarity index. The results suggest that Ge positively correlates with Cu in Sp-II, but with Ag in Sp-III, differences that may be related to the temperature of formation. The metamorphic basement is the main source of Ge in the Maoping deposit. Additionally, coal seams in this deposit could potentially be important contributors to Ge enrichment. A model for Ge mineralization was proposed in which the mixing of the Ge-bearing metamorphic fluids with the Ge-bearing basin brines precipitated sphalerite, and the Ge was incorporated into Sp-II and Sp-III via 2Cu⁺ + Ge⁴⁺ ↔ 3Zn²⁺ and 2Ag⁺ + Ge⁴⁺ ↔ 3Zn²⁺, respectively, under medium sulfur fugacity and low oxygen fugacity conditions.