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The Yangla Cu skarn deposit is located in the central part of the Jinshajiang Suture Zone, southwest China, with a total reserve of 150 Mt Cu @ 1.03%. The newly discovered antimony orebodies at the depth of Yangla are strictly controlled by the stratum, structure, and lithology, which are lenticular and vein-like within the marble fracture zone, which can provide a window into multistage mineralization and ore genesis at Yangla. Mineralization can be divided into three types, Cu–Pb–Zn (skarn) pyrite, galena, and sphalerite, Cu (porphyry) chalcopyrite and pyrite, and Sb (hydrothermal) stibnite and pyrite. The mineral assemblages were stibnite + pyrite + calcite + quartz ± minor scheelite in antimony ores. This study presents quantitative measurements of the trace element compositions of pyrite and stibnite from the Yangla antimony ores. Analysis of pyrite with electron probe microanalysis (EPMA) showed enrichment in Co, Ni, Sb, As, and Mo, and deficit in its S and Fe contents when compared to the stoichiometric concentrations of S and Fe in pyrite. The Sb-related pyrite may belong to sedimentary-reworked genesis and may be modified by hydrothermal fluids, thereby presenting a certain difference (i.e., crystal morphology, texture, and chemical composition) compared to the skarn and porphyry Cu-related pyrite in the Yangla Cu skarn deposit. Analysis of stibnite with EPMA and inductively coupled plasma-mass spectrometry showed enrichment in As, Pb, Sn, Pb, Cu, and Zn, and presented much higher Sb contents and slightly lower S contents when compared to the stoichiometric concentrations of Sb and S in stibnite. Statistical analysis of the stibnite trace elements showed correlations for the elemental pairs Cu–Pb, As–Sb, and Sn–Pb, and the coupled substitution equations Sb3+ ↔ Cu+ + Pb2+, Sb3+ ↔ As3+, and Sn2+ ↔ Pb2+ may be the major factors governed the incorporating Cu, Pb, As and Sn within the stibnite. Moreover, this study preliminary shows that the antimony mineralization may belong to a carbonate replacement hydrothermal genesis at Yangla. [ABSTRACT FROM AUTHOR]

Pyrite, the most common sulfide mineral, is a ubiquitous component of many hydrothermal gold deposits. Geochemical patterns within the refractory pyrite structure represent a valuable repository of information that can help constrain the sources of ore-forming materials, and the evolution of ore-forming processes over time. However, there are still a lot of debates on the mechanisms of physico-chemical processes in ore-forming fluid controlling trace element and sulfur isotope distributions in pyrite during growth. In our manuscript, we use cutting-edge complementary microanalytical methods to understand the origin and evolution of zoned gold-bearing pyrite in samples from the largest gold deposit in the Ailaoshan gold belt, SW China, Zhenyuan (exceeding 100t Au, average grade: 5.3 g/t). Pyrite, arsenopyrite, chalcopyrite, and stibnite are the most abundant sulfide minerals in most orebodies. Of these, pyrite is dominant and is also the most important host for gold. Two types of pyrite can be clearly distinguished: framboidal pyrite and hydrothermal pyrite. Gold is most commonly hosted by hydrothermal pyrite. Framboidal pyrite, mainly hosted by carbonaceous slate, hosts negligible Au, and features low δ34S values ranging from − 35.0 (± 0.9) to − 25.6 (± 1.0)‰. Hydrothermal pyrite is characterized by complex intra-grain zoned textures with alternating As-rich and As-poor bands readily recognizable on backscattered electron images. Scanning electron microscopy and trace-element analyses show that both visible and invisible gold occur only in the As-rich bands. Compared to the As-poor bands (72.1% of Au concentration data < 1.96 ppm, n = 43), the As-rich bands are characterized by far higher concentrations of Au (up to 1420 ppm), Cu, Ag, Sb, and Tl, but lower concentrations of Co and Ni. In-situ sulfur isotope analysis indicates that the δ34S values of As-rich zones range from − 7.3 (± 0.6) to 2.9 (± 0.6)‰ and are similar to those of As-poor zones (from − 6.9 (± 0.7) to 2.8 (± 0.6)‰), but distinct from the framboidal pyrite. Combined with published fluid inclusion data and a probable age for the magmatic event associated with mineralization, these data suggest that magmatic–hydrothermal fluids contributed most ore-forming materials and that periodic boiling led to formation of the rhythmic As-rich and As-poor bands in pyrite. Our data for pyrite constrain the evolution of ore-forming processes and provide new insights into the formation of zoned pyrite, with the conclusions having broad implications for analogous hydrothermal gold deposits worldwide. [ABSTRACT FROM AUTHOR]

The Gongguan deposit in southern Qinling district, central China, is characterized by a Hg and Sb metal association, with proven reserves of 7,543 t Hg and 17,100 t Sb. The Hg-Sb mineralized veins are primarily hosted by local Lower Devonian dolomite. Three primary paragenetic stages have been identified, including (I) pyrite-dolomite-quartz, (II) stibnite-cinnabar-quartz-calcite and (III) post-ore calcite. Dominant mercury and antimony mineralization occurred in stage II. Fluid inclusion microthermometry of quartz and calcite reveal that the Hg-Sb mineralization is associated with a low temperature (142° to 240 °C) and low salinity (< 8.6 wt% NaCl equivalent) fluid, belonging to a H2O-NaCl ± CO2 system. The H–O isotope compositions (δDH2O = −84 to −63‰, δ18OH2O = 1.3 to 12.7‰) of the hydrothermal fluid suggest a mixture of metamorphic fluid and meteoric water. In situ sulfur isotope results of cinnabar (δ34S = 3.4 to 14.5‰), stibnite (δ34S = 4.9 to 10.5‰) and pyrite (δ34S = 3.8 to 5.4‰) indicate sulfur sources from decomposition of diagenetic pyrite and/or the thermochemical sulfate reduction in local sedimentary rocks. In situ obtained 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios (18.006 to 18.362, 15.445 to 15.610 and 37.871 to 38.288, respectively) of stibnite and pyrite substantially differ from those for the regional Carlin Au-Sb and SEDEX Pb–Zn ore deposits. The lead isotope results indicate that the underlying Paleozoic (Silurian to Cambrian) strata and Precambrian metamorphic basement supplied substantial metals for the studied Hg-Sb deposit, whereas the host Devonian carbonates did not contribute significant metals. In summary, we propose that fluid mixing between metamorphic fluid and meteoric water was the main cause for carbonate-hosted Hg-Sb deposition at Gongguan, which reduced the stibnite solubility, oxidized mercury (Hg0 to Hg2+), favoring the process of dedolomitization. [ABSTRACT FROM AUTHOR]

To systematically study the environmental problems of heavy metal pollution in soils caused by antimony (Sb) smeltery in central and southern China, the pollution levels, sources and risks of heavy metals were explored based on the GIS, pollution indices, multivariate statistical methods combined with positive matrix factorization (PMF) model, and risk assessment model. The results showed the average contents of Hg, Pb, Cd, Cr, As, and Sb in soils were 0.06, 47.77, 2.88, 53.12, 21.22 and 20.53 mg/kg, respectively. Except for Hg and Cr, the contents of other metals all exceeded the background values of Hunan Mountain soil (BV). Spatial distribution of heavy metal contents and pollution indices (Igeo, PLI, and RI) indicated that above 50% of the studied area were polluted moderately by Cd and Sb, and 77% of sampling sites were under a severe ecological risk level. Multivariate statistics and PMF analysis suggested that Cd (76.9%) and As (57.7%) were mainly from agricultural activities, followed by Sb smelting (12.7% for Cd and 25% for As). The atmosphere deposition of transportation and industrial activities, antimony smelting and nature origin respectively contributed 40.6%, 20.5% and 30.7% of Hg in soils. Sb (73.9%) and Pb (54.5%) were from the Sb smelting, followed by the high geological background (35.6% for Pb and 25% for Sb). Cr (69.7%) was natural origin, but agricultural activities had 21.6% of contribution to its accumulation in soils. Significantly, the values of non-carcinogenic risk (HI) for children under three exposure pathways in different soil depths was bigger than 1 and exceeded the "acceptable level" of risk, and the total carcinogenic risks (TCR) for adults and children were exceeded 1 × 10–4 with an unacceptable carcinogenic risk for human body. Oral ingestion of As was the remarkable characteristic of risk, which should be paid attention to. [ABSTRACT FROM AUTHOR]

Antimony pollution in the groundwater of the Xikuangshan (XKS) antimony (Sb) mine area in China's Hunan Province has attracted increasing attention. A total of 43 water samples were collected to help understand the hydrogeochemical characteristics, identify the Sb source, and evaluate the water–rock interactions of the Shetianqiao aquifer (SA). The Sb concentrations in shallow and deep SA water samples were 0.1–47.4 mg L−1 and 0.3–19.2 mg L−1, respectively. Stibnite oxidation and leaching from arsenic alkali residue mine wastes were the main Sb sources for the shallow SA water, whereas stibnite oxidation and stronger water–rock interaction were the predominant Sb sources for the deep SA water. The higher Sb concentration (> 10.0 mg L−1) in shallow SA water was predominantly induced by weathering of Sb-bearing minerals, evaporation/concentration effects, and cation exchange, whereas the higher Sb concentration in deep SA water was largely caused by weathering of Sb-bearing minerals, evaporation/concentration effects, ion exchange, and competitive adsorption. These findings provide a more detailed understanding of the geochemical behavior of Sb in groundwater and can be used to develop suitable Sb pollution management strategies. [ABSTRACT FROM AUTHOR]

Elevated soil concentrations of antimony (Sb) and co-contaminants are frequently encountered where antimony has been mined on a large scale. For instance, the Xikuangshan antimony mine in central South China has sustained, over many centuries, dispersed and spatially variable input of toxic elements into the soil ecosystem. We utilized this unique environment to assess the impact of geochemical conditions on soil microbiology. Geochemical conditions were assessed by monitoring absolute and available fractions of toxic elements and disrupted soil properties. Soil microbiology was studied by high-throughput sequencing and statistical analysis, including principle component analysis and canonical correspondence analysis. Results show that Sb concentrations were ranged from 970 to more than 24,000 mg/kg. As concentrations were three times higher than the regional background values and ten times higher for Pb, 590 times higher for Cd and 30 times higher for Hg. About 5–10% of the total soil Sb was environmentally mobile. Microbial diversity was high, and soil properties such as pH, organic matter, iron and sulfate controlled the absolute microbial activity. We identified strong positive and negative correlations with specific bacterial taxonomic groups which show: (1) an intolerance of available fractions for all elements, e.g., Gemmatimonas, Pirellula, Spartobacteria; (2) a good tolerance of available fractions for all elements, e.g., Povalibacter, Spartobacteria; and (3) a mixed response, tolerating available Sb, Hg and Cd and inhibition by As, Pb, e.g., Escherichia/Shigella and Arthrobacter, and in reverse, e.g., Gemmatimonas and Sphingomonas. The site hosts great diversity dominated by Gram-negative organisms, many with rod (bacillus) morphologies but also some filamentous forms, and a wide range of metabolic capabilities: anaerobes, e.g., Saccharibacteria, metal oxidizing, e.g., Geobacter, chemoautotrophs, e.g., Gemmata, and sulfur reducing, e.g., Desulfuromonas. The bioremediation potential of Arthrobacter and Escherichia/Shigella for Sb control is highlighted. [ABSTRACT FROM AUTHOR]

Arsenic (As) and antimony (Sb) are both toxic metalloids that are of primary concern for human health. Mining activity has introduced elevated levels of arsenic and antimony into the rivers and has increased the risks of drinking water contamination in China. Due to their mobility, the majority of the metalloids originating from mining activities are deposited in the river sediments. Thus, depending on various geochemical conditions, sediment could either be a sink or source for As and Sb in the water column. Microbes are key mediators for biogeochemical transformation and can both mobilize or precipitate As and Sb. To further understand the microbial community responses to As and Sb contamination, sediment samples with different contamination levels were collected from three rivers. The result of the study suggested that the major portions of As and Sb were in strong association with the sediment matrix and considered nonbioavailable. These fractions, however, were also suggested to have profound influences on the microbial community composition. As and Sb contamination caused strong reductions in microbial diversity in the heavily contaminated river sediments. Microorganisms were more sensitive to As comparing to Sb, as revealed by the co-occurrence network and random forest predictions. Operational taxonomic units (OTUs) that were potentially involved in As and Sb metabolism, such as Anaerolinea, Sphingomonas, and Opitutus, were enriched in the heavily contaminated samples. In contrast, many keystone taxa, including members of the Hyphomicrobiaceae and Bradyrhizobiaceae families, were inhibited by metalloid contamination, which could further impair crucial environmental services provided by these members. [ABSTRACT FROM AUTHOR]

Mesozoic mineral deposits in South China include world-class deposits of W, Sn and Sb and those that provide the major sources of Ta, Cu, Hg, As, Tl, Pb, Zn, Au and Ag for the entire country. These deposits can be classified into polymetallic hydrothermal systems closely related to felsic intrusive rocks (Sn-W -Mo granites, Cu porphyries, polymetallic and Fe skarns, and polymetallic vein deposits) and low-temperature hydrothermal systems with no direct connection to igneous activities (MVT deposits, epithermal Au and Sb deposits). Recent studies have shown that they formed in the Triassic (Indosinian), Jurassic-Cretaceous (Early Yanshanian), and Cretaceous (Late Yanshanian) stages. Indosinian deposits include major MVT (Pb-Zn-Ag) deposits and granite-related W-Sn deposits. Early Yanshanian deposits are low-temperature Sb-Au and high-temperature W-Sn and Cu porphyry types. Many Late Yanshanian deposits are low-temperature Au-As-Sb-Hg and U deposits, and also include high-temperature W-Sn polymetallic deposits. The formation of these deposits is linked with a specific tectonothermal evolution and igneous activities. This special issue brings together some of the latest information in eight papers that deal with the origins and tectonic environments of mineral deposits formed in these stages. We anticipate that this issue will stimulate more interests in these ore deposits in South China. [ABSTRACT FROM AUTHOR]

The article presents abstracts of several studies on environmental geochemistry. Some of the abstracts presented include "Biogeochemical Cycling of Nutrients in Karstic Catchments, Southwestern China: Linkages to Changes of Eco-Environments," by Congqiang Liu and "Emerging Organic Contamination in China," by Guibin Jiang and colleagues.

Focuses on a study on the metallogenic chemistry of antimony (Sb)-mineralization in the southern margin of the north China platform. Geological setting; Mineralogy and geochemistry of the ore deposits; Conclusion.