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[Display omitted] • The Jinding deposit contains high content of associated critical metal Cd, Tl, Ag. • The enrichment of Fe assists incorporation of components Ge + Mn + Pb + As + Tl. • The enrichment of Cd assists incorporation of components Cu + Ag + Sb. • Cd and Fe zonation at sphalerite indicate a potential exploration deposit. The Jinding deposit is well-known to contain high concentrations of metals Zn, Pb, Cd, Tl, Ag, etc. in the world. The associated critical metals and their substitution mechanisms were wildly concerned. This study investigated and compared sphalerites using a combination of textural, trace element, and sulfur isotopic analyses to give insights into element substitution mechanisms and possible sources of ore-forming fluids and to constrain processes involved in ore genesis of the world-class Jinding sediment-hosted Zn-Pb deposit. LA-ICP-MS analyses reveal chemical zoning in the sphalerites together with the coupling of two main groups of trace elements substitution mechanisms: one is Fe + Ge + Mn + Pb + As + Tl and vacancies to substitute Zn, and the other is Cd + Cu + Ag + Sb to substitute Zn. The incorporation of trace elements is facilitated by the replacement of Zn by Cd and Fe. These two group elements have distinct color oscillatory zonation and are intertwined in the trace element LA-ICP-MS element maps. The sulfur isotopic values show high isotope fractionation in the sphalerite from −28.4 to −0.5 ‰, suggesting a bacteriogenic sulfur origin at Jinding. Sphalerite sample has observed that sulfur isotope is correlated with Fe concentration and anti-correlated with Cd concentration. These variations in isotope fractionation and trace element disequilibrium partitioning were interpreted as the effects of temperature and pH with less influence from sulfur activity. These variability zones of sphalerite alternately enriched in Cd- and Fe-related elements suggested that ore fluids may flow from metal-fertile sedimentary/basement sequences during their ascent, and colloform sphalerite was likely formed by a high degree of supercooling, over-saturation, and rapid mixing between bacteriogenic sulfur and metal-rich in spaces of collapse dome. Based on our observations, we suggested that these variability zones of layered sphalerite alternately enriched in Cd and Fe would likely provide useful insight for a potential economic Zn-Pb and associated critical metals mineral exploration deposit. [ABSTRACT FROM AUTHOR]

• There are three types of pyrite with sector zoning, massive overgrowth, and replacement relics. • Two principal types of sphalerite were identified with fragmented and replacement textures. • Different generations of pyrite have variable trace elements, reflecting an evolving hydrothermal system. • Trace element contents of pyrite indicate that the Qilinchang deposit was formed from low temperature hydrothermal fluids. The Qilinchang Pb-Zn deposit (̴ 5Mt of sulphide ore at mean grades of 2.3–9.2% Pb and 2.7–22.5% Zn) is hosted in Early Carboniferous carbonate rocks and mainly controlled by NE-, NS-, and NW- trending structural belts between the Xiaojiang and Zhaotong-Qujing buried faults. Ore minerals are sphalerite, galena, pyrite, chalcopyrite, and marmatite, whereas gangue minerals are dolomite, calcite, and quartz. Three generations of pyrite are recognized; these include fine-grained anhedral pyrite (Py-I), medium-grained anhedral to subhedral hydrothermal pyrite (Py-II), and coarse-grained subhedral to euhedral hydrothermal pyrite (Py-III), while the sphalerite occurs in two forms as fine-grained intergrown with galena and associated with Py-I and Py-II. Laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis was performed to evaluate trace element compositions of pyrite and sphalerite from different generations of ores. Py-I has relatively higher concentrations of Mg, Mn, Co, Ni, and Tl. Py-II in Cu, As, Se, Mo, and Sb relative to pyrite of other generations. The contents of trace elements in Py-III are variable but significantly enriched in Ti, V, Bi, Ag, and Pb compared to Py-I and Py-II. This variation indicates that these elements occur as micro mineral inclusions of possible Ag-Pb-bearing phases. Sphalerite of stage I has higher concentrations of Mn, Fe, Co, Ni, Cu, Ga, Ge, As, Ag, Cd, In, Sb, Hg, and Pb than stage II. These elements are homogeneously distributed in all samples analyzed. The incorporation of these elements is primarily through simple substitution mechanisms (e.g., 2Zn2+ ↔ Cu+ + In3+) as indicated from binary plots. Principal component analyses (PCA) applied to LA-ICP-MS dataset for pyrite reveal two main clusters; Py-I enriched in Ni, Co and As, Py-II and Py-III high in with V, Mn, Cu, Zn, Se, Mo, Ag, Sb, Au, and Bi. Likewise, the PCA also confirms two clusters of elements for sphalerite; Ge, Cu, As, Sb, Ag, Fe, and Cd corresponding to Sph-I and In, Sn, and Ga corresponding to Sph-II. Py-I has higher Co/Ni ratio ranging from 0.04 to 1.6 compared to Py-II and Py-III having Co/Ni ratios from 0 to 0.706 and 0 0.696, respectively. We report that the pyrites from the Qilinchang deposit have Co/Ni ratios slightly lower than typical Mississippi Valley-Type (MVT) deposits (0.2–7.2) and different from iron oxide copper-gold (IOCG) and porphyry Cu deposits. Considering these geochemical signatures, it can be suggested that the Qilinchang deposit was not related to magmatic activities. We thus propose that the ore-forming fluids responsible for the formation of the deposit were generated from a low-temperature environment, similar to typical MVT deposits. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sphalerite chemistry combined with ML methods were used to classify deposit types. • KNN, NN, and RF algorithms are more efficient than other ML methods in the classification tasks. • Ge, Sn, Co, Mn, Ga, and In in sphalerite are the most important discriminant elements. • Binary discrimination diagrams based on PCA and PLS-DA are provided. Sphalerite can form in different geological environments and is the main ore mineral of most Pb-Zn deposits. Trace elements in sphalerite combined with machine learning (ML) methods have been used for deposit type discrimination. However, the performance of different multivariate and ML methods is not systematically compared. Here more than four thousand laser ablation inductively coupled plasma mass spectrometry data from more than one hundred deposits were compiled and investigated by different multivariate and ML methods. Unsupervised multivariate and ML methods including principal component analysis (PCA) and t -distributed stochastic neighbor embedding (t -SNE), and supervised multivariate and ML methods including partial least squares-discriminant analysis (PLS-DA), logistic regression (LR), support vector machine (SVM), K-nearest neighbors (KNN), random forest (RF), naïve Bayes (NB), and neural network (NN) are used to classify deposit types. The models are constructed for five deposit types, Mississippi Valley-type (MVT), Volcanogenic Massive Sulfide (VMS), sedimentary exhalative (SEDEX), Epithermal, and Skarn deposits, based on twelve elements in sphalerite, Fe, Pb, Mn, Co, Cu, Ga, Ge, Ag, Cd, In, Sn, and Sb. The PCA and PLS-DA methods show similar clustering results, where Epithermal, MVT, SEDEX, and Skarn deposits can be separated from other deposit types. The t -SNE method is only efficient in discriminating MVT, SEDEX, and Epithermal deposits. The KNN, RF, and NN methods show better performance than LR, SVM, and NB in terms of average accuracy and precision. The PCA, t -SNE, and PLS-DA methods have advantages in data visualization, whereas KNN, NN, and RF methods are more suitable for classification tasks. Feature importance analyses of the PLS-DA and RF methods show that the most important discriminant elements in the classification are Ge, Mn, In, Sn, Ga, and Sb. The models based on PCA, PLS-DA, KNN, NN, and RF are used to predict sphalerite samples with uncertain origins. All the models give similar classification results for deposit types, which are consistent with the ore-forming geological setting. The multivariate and ML models, including discrimination diagrams of PCA and PLS-DA, can be used as the first screening for the type of Pb-Zn mineralization in mineral exploration. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ge is mainly coupled with Cu in sphalerite, locally associated with Pb, Ag, and Mn. • The substitution mechanism of Ge will vary with textures and color of sphalerite. • Crystal structure or planes, texture, and temperature affect Ge, Ga, In contents. • Ge, Ga, and In behave differently during sphalerite precipitation. The low-medium temperature Zn-Pb deposits in the Sichuan-Yunnan-Guizhou (SYG) metallogenic region contain not only Pb and Zn but also abundant critical metals such as Ge, Ga, and In. The majority of previous studies focus on the genesis of Pb and Zn metals, and the research on Ge, Ga and In in the SYG region has become a topic in recent years due to economic importance of these metals. In this review, the distribution, occurrence, and enrichment mechanism of Ge, Ga, and In in Zn-Pb deposits in the SYG region is summarized. Sphalerite is the main host mineral of Ge, Ga, and In, with contents of up to ∼1300 ppm, ∼600 ppm, and ∼1191 ppm, respectively. Pyrite from the Fule Zn-Pb deposit is also rich in Ge (up to 340 ppm), which may be due to involvement of magmatic components in the ore-forming fluids. Germanium, Ga, and In mainly appear in the form of isomorphism in sphalerite. Independent minerals of Ge such as ruizhongite (Ag 2 □)Pb 3 Ge 2 S 8), are only found in the Wusihe Zn-Pb deposit. Copper is the main coupling ions for substitution of Ge, Ga, and In in sphalerite. However, the positive correlation of Ge with Pb, Mn and Ag in the sphalerite of Huodehong, Shaojiwan, Shanshulin, and Qingshan Zn-Pb deposits may indicate other means of substitution or existence of nanometer Ge minerals with similar composition to the ruizhongite. The substitution mechanisms of Ge and Ga vary with layers in the zoned sphalerite from the Nayongzhi Zn-Pb deposit, possibly indicating that physical or chemical variations in fluids will affect the substitution ways of Ge and Ga in sphalerite. The growth direction and crystal structure of ZnS also exert control over the contents of Ge, Ga, and In. The enrichment degree of Ge, Ga, and In changes between (1 1 0) and (1 1 1) crystal planes, and the wurtzite structure is beneficial to the infiltration of large ions (Ge, Ga, and In). Compared to sphalerite with euhedral texture, colloform sphalerite is conducive to the enrichment of Ge. For zoned sphalerite such as the rhythmic banding and the conventional zone, the former lacks zoning of Ge, Ga and In but the latter shows elemental zonation and Ge is enriched in the black domains. The correlation between the contents of Ge, Ga, and possible In in sphalerite and Pb or Zn isotopes of sulfides indicates the significant contribution of basement rocks for the enrichment of these metals. During the mineralization process, Ge tends to be enriched in dark or early sphalerite, including the Daliangzi, Tianbaoshan, Huize, Nayongzhi, Fule, Fuli, Wusihe, and Maoping deposits, which may be due to the variations in temperature or fluid evolution. The opposite variation trend of Ge and Ga with sphalerite color or stage in the Daliangzi, Nayongzhi, Maoping, Shaojiwan, and Wusihe Zn-Pb deposits indicates that Ge and Ga may behave differently during precipitation of sphalerite. [ABSTRACT FROM AUTHOR]

• Zn dominates early mineralization stage, whereas late stage features Pb-Sb. • Sulfur is mainly of magmatic source, with a small amount of sulfur from TSR. • Mixing of sulfur-rich fluid with metalliferous brine caused sulfide precipitation. • Temperature is the most important factor to control the metal precipitations. The Lanuoma deposit, located in the Sanjiang Tethyan metallogenic domain, shows a characteristic assemblage of Pb-Zn-Sb mineralization, distinguished from those in other sediment-hosted base metal deposits of this region. The ore textures reveal two mineralization stages: the early stage is characterized by Zn mineralization with occurrences of porous pyrite (Py2) and yellowish-brown sphalerites (Sp1), and the late stage is characterized by Sb-Pb mineralization with occurrences of subhedral-euhedral pyrite (Py3), yellowish-white sphalerites (Sp2), sulfosalts consisting of boulangerite, zinkenite, sorbyite and plagionite and calcite veins. The framboidal pyrites (Py1) predate Pb-Zn-Sb mineralization. Py2 has higher Zn contents (16.97–621.67 ppm, mean: 181.17 ppm) than Py3 (Zn: 0.76–323.44 ppm, mean: 29.58 ppm) by up to one order of magnitude. The Se contents of Py2 (Se: 5.46–87.82 ppm, mean: 50.96 ppm) are also one order of magnitude higher than those of Py3 (Se: 1.64–10.99 ppm, mean: 4.35 ppm). Sp1 is characterized by one order of magnitude higher contents of Fe (381.99–9046.64, mean: 4875.50 ppm) and Se (4.02–72.51 ppm, mean: 34.70 ppm) than Sp2 (Fe: 287.53–584.02 ppm, mean: 416.75 ppm; Se: 2.89–10.80 ppm, mean: 6.20 ppm). However, the average content of Cd (4256.38 ppm) in Sp2 is almost twice that in Sp1 (2635.74 ppm). The higher Se contents in Py2 coupled with higher Se and Fe contents in Sp1 indicate that Py2 and Sp1 had higher precipitation temperatures than Py3 and Sp2. Sulfur isotope compositions of pyrites and sphalerites acquired by NANO-SIMS and LA-MC-ICP-MS suggest two origins: the sulfur of Py2 (δ34S: −3.0 to 2.3‰), Sp1 (δ34S: 0.2–0.9‰) and Sp2 (δ34S: 0.7–2.5‰) was mainly of magmatic source, and sulfur reduced via thermochemical sulfate reduction participated in the formation of Py3 (δ34S: 0.2–6.0‰) and S-Sb-Pb minerals intergrown with Py3. The sulfur isotope compositions of Py1 (δ34S: −31.8 to −19.4‰) indicate a biogenic origin associated with bacterial sulfate reduction. A fluid mixing model is suggested to interpret the genesis of the Lanuoma Pb-Zn-Sb deposit: mixing of a reduced S-bearing fluid with a metalliferous basinal brine resulted in the precipitation of sulfides. Temperature was the most important factor controlling metal precipitation in the Lanuoma deposit. [ABSTRACT FROM AUTHOR]