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Antimony (Sb) is widely utilized in modern industries and classified as a critical mineral worldwide. China possesses the most abundant Sb mineral resources globally, with over 70% of proven reserves concentrated in southern China. However, due to excessive exploitation, the lifespan of Sb reserves is less than ten years. Therefore, the knowledge of Sb needs to be urgently strengthened. Here, the effectiveness of the geochemical block method to delineate the prospective areas of Sb deposits and determine the potential resource of Sb was studied, with geochemical data covering 2.3 million km2 across southern China. The statistical results showed that the median concentration of Sb in stream sediments (1.05 ppm) in southern China was 1.5 times that of whole China, indicating a significantly elevated background level of Sb in southern China. By setting the threshold value at 2.98 ppm, a total of nine distinct geochemical blocks were delineated. Remarkably, 85% and 76% of the large and medium Sb deposits were located within these geochemical blocks, respectively. Taking the block containing the Xikuangshan giant Sb deposit in Hunan Province as the model, the metallogenic coefficient of Sb is calculated to be 0.32%. The total potential Sb resources in southern China within a depth of 1000 m are estimated to be 21.939 million tons, which are primarily concentrated in the provinces of Hunan, Guangxi, Yunnan, and Guizhou. When the threshold value is set at 4.19 ppm, the predicted potential resources of Sb are 21.45 million tons in twelve blocks, which closely approximate 21.939 million tons. The estimated Sb resource in this study significantly surpasses the proven reserves. The periphery and deep areas of known Sb deposits still hold promising prospects for exploration. This study highlighted the effectiveness of employing the geochemical block method to estimate the potential resources of Sb and determined the ore-prospecting direction of Sb deposits. However, it is important to acknowledge and address the overestimation of predicted resources resulting from the high geological background. [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]