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Geochemical Study of Trace Elements and In Situ S–Pb Isotopes of the Sachakou Pb–Zn Deposit in the Aksai Chin Region, Xinjiang

Xiaojian Zhao

^1,2,3,4

Nuo Li

^1,*,

Tingbin Fan

⁵,

Jing Sun

⁶,

Qinglin Sui

⁷,

Huishan Zhang

⁴,

Zhouping Guo

⁴,

Jianatiguli Wusiman

^1,3,

Kai Weng

⁴ and

Yanjing Chen

^8,*

Xinjiang Research Center for Mineral Resources, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China

College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830046, China

University of Chinese Academy of Sciences, Beijing 100029, China

⁴

Technology Innovation Center for Intelligent Remote Sensing Monitoring of Natural Resources in the Upper and Middle Reaches of the Yellow River, MNR, Xi’an Center, China Geological Survey (Northwest China Center for Geoscience Innovation), Xi’an 710119, China

⁵

Geological Bureau, Xinjiang Uyghur Autonomous Region, Urumqi 830000, China

⁶

Geological Exploration Institute of Shandong Zhengyuan, China Metallurgical Geology Bureau, Weifang 261057, China

⁷

School of Resources and Safety Engineering, University of South China, Hengyang 421001, China

⁸

MOE Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, China

Authors to whom correspondence should be addressed.

Minerals 2025, 15(3), 271; https://doi.org/10.3390/min15030271

Submission received: 27 November 2024 / Revised: 26 February 2025 / Accepted: 4 March 2025 / Published: 6 March 2025

(This article belongs to the Special Issue Genesis and Evolution of Pb-Zn-Ag Polymetallic Deposits: 2nd Edition)

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Abstract

The sulfide Pb–Zn deposits in the Aksai Chin region of Xinjiang have long been subject to debate regarding their genetic classification due to the unclear origin of the ore-forming components. This study focuses on the Sachakou Pb–Zn deposit, the most representative deposit in the region, and integrates field investigations, petrographic observations, in situ LA-ICP-MS trace element analysis, and in situ S–Pb isotope analysis. The deposit is hosted within the siliceous rock and silicified limestone of the Lower Jurassic Bagongbulansha Formation, with ore bodies controlled by structural and stratigraphic factors. Three mineralization stages have been identified in the Sachakou deposit: a red–brown sphalerite mineralization stage (S1), a light-brown sphalerite stage (S2), and a galena mineralization stage (S3). The trace elements in sphalerite indicate that the mineralization process is unrelated to magmatic activity. The mineralization temperature, determined using a GGIMFis geothermometer, ranges from 294 °C to 121 °C. The δ³⁴S_V-CDT values of sulfides range from −4.93‰ to 1.24‰, suggesting that the Jurassic gypsum layer served as the sulfur source. The lead isotope ratios of ²⁰⁶Pb/²⁰⁴Pb range from 18.308 to 18.395, of ²⁰⁷Pb/²⁰⁴Pb—from 15.669 to 15.731, and of ²⁰⁸Pb/²⁰⁴Pb—from 38.595 to 38.776, indicating that the ore-forming metals were predominantly sourced from the upper crust. Based on geological and geochemical characteristics, the Sachakou Pb–Zn deposit is classified as a sedimentary-hosted epizonogenic hydrothermal deposit.

Keywords:

Sachakou Pb–Zn deposit; trace elements in sphalerite; in situ S–Pb isotopes; type of deposit

1. Introduction

The classification of hydrothermal deposits has long been a contentious issue in mineral deposit studies. Chen [1] categorized hydrothermal deposits into three distinct systems based on endogenic metallogenic processes: epizonogenic, metamorphic, and magmatic hydrothermal mineral systems. Within this framework, epizonogenic hydrothermal deposits are further subdivided into volcanic-hosted epizonogenic hydrothermal deposits, sedimentary-hosted epizonogenic hydrothermal deposits, and seafloor hydrothermal sedimentary deposits [1,2]. These classifications encompass several common Pb–Zn deposit types described in the literature, including MVT, SEDEX, Epithermal, and VMS deposits, offering a novel perspective for understanding the genesis of Pb–Zn mineralization.

Sphalerite is an important sulfide in hydrothermal deposits, recording key physicochemical conditions of ore formation [3,4,5]. The trace elements in sphalerite (e.g., Cd, Ga, Ge, In) are not only economically valuable, but also provide critical insights through their concentrations and modes of occurrence for tracing the source of metals [6,7,8,9], reconstructing ore-forming temperatures [10,11,12], and identifying deposit types [4,13,14,15]. Integrating geological characteristics, sulfur and lead isotopic compositions, and sphalerite trace element compositions enables further refinement of the genetic classification of ore deposits.

The Karakoram–Sanjiang metallogenic province, located in the eastern part of the Tethys metallogenic domain, has developed the largest lead–zinc belt in China. Over the past 12 years, more than forty Pb–Zn deposits and occurrences have been identified in the Aksai Chin region of Xinjiang, at the southern end of the Karakoram metallogenic belt. Based on the statistics of this study, the cumulative Pb + Zn metal reserves exceed 26 Mt, establishing this region as the largest Pb–Zn resource base in China. These Pb–Zn deposits in this region are hosted in Mesozoic strata of the Tianshuihai Terrane, with orebodies typically exhibiting stratiform, stratiform-like, or lenticular morphologies [16,17]. Based on ore features, the Pb–Zn deposits can be classified into non-sulfide deposits, represented by Huoshaoyun, and sulfide deposits, exemplified by Sachakou and Yuanbaoling. However, compared to the extensive studies on non-sulfide Pb–Zn deposits (e.g., Huoshaoyun [18,19,20,21,22]), research on the region’s widely distributed sulfide Pb–Zn deposits remains limited. Previous studies on sulfide Pb–Zn deposits primarily focused on debates regarding the sources of ore-forming fluids, metals, and the classification of deposit types: (1) some researchers suggest that the ore-forming metals in sulfide Pb–Zn deposits originate from the upper crust and classify them as MVT or SEDEX deposits [17,23,24]; (2) others argue that the ore-forming fluids and metals are closely related to deep magmatic activity, classifying these deposits as magmatic-related carbonate-replacement Pb–Zn deposits [25,26]. Therefore, determining the sources of ore-forming components in the regional sulfide Pb–Zn deposits is crucial for understanding their genetic mechanisms.

The Sachakou Pb–Zn deposit, located in the south-central part of the Aksai Chin region in Xinjiang, represents the largest and most significant sulfide deposit in the area. It hosts over 1.6 Mt of metal, including 1.33 Mt of zinc and 0.32 Mt of lead, with average grades of 4.73% Zn and 1.14% Pb. In this study, we present the results of comprehensive investigations on the sulfide ores, focusing on geological and geochemical characteristics. These investigations include detailed sphalerite trace element analysis using LA-ICP-MS and in situ S and Pb isotopic analyses of metallic sulfides. The primary objectives of this research are to (1) identify the trace element enrichment characteristics and substitution mechanisms in sphalerite and reconstruct ore-forming temperatures; (2) provide new constraints on the sources of ore-forming metals; and (3) refine the genetic classification of the deposit. The findings will provide crucial insights into the mechanisms of regional Pb–Zn mineralization and guide targeted exploration in analogous settings.

2. Regional Geology

The Aksai Chin region is located on the northwestern margin of the Tibet Plateau (Figure 1a), at the southern end of the West Kunlun–Karakoram Orogenic Belt, spanning the Tianshuihai Terrane and the South Qiangtang Terrane (Figure 1b). The regional stratigraphy ranges from the Proterozoic to the Cenozoic, with Mesozoic strata being predominant. The Paleozoic and Mesozoic strata are characterized by a series of minor anticlines and synclines, predominantly oriented along northwest-trending axes, and are also host to a set of north-trending imbricate reverse thrusts (Figure 1c).

The Mesozoic clastic and carbonate rocks constitute the primary host rock series for Pb–Zn deposits in the region. The Heweitan Formation (T₂h) exhibits a deep-water turbidite system in its lower part, with sandstone and slate interbedded with deep marine siliceous rocks, transitioning upward into shallow marine shoreface deposits dominated by clastic rocks with intercalations of limestone. The Keleqinghe Formation (T₃k) represents a slope to semi-deep water turbidite system, characterized by siltstone and feldspathic quartz sandstone. Transitional marine–terrestrial depositional systems dominate the Bagongbulansha Formation (J₁b), with conglomerates, siltstones, and limestones. The Longshan Formation (J₂l) consists of shallow marine carbonate rocks, locally intercalated with clastic rocks and basalt. The Tielongtan Group (K₂T) features medium- to thick-bedded limestone, siltstone, and mudstone, with basal conglomerates occasionally observed. Gypsum layers are extensively developed in the Jurassic to Cretaceous strata, with thicknesses ranging from a few centimeters to 200 m [27,28].

Figure 1. Geographical location map (a), tectonic sketch map (b) (modified after Gao et al. [29]), and geological and mineral resources map (c) (modified after Zhao et al. [16]) of the Aksai Chin region.

The Aksai Chin region is characterized by intense tectonic activity, with the development of major faults and folds. Major faults, from north to south, include the Dahongliutan Fault, Qiaotianshan Fault, Heweitan Fault, Kongkashankou Fault, and Altyn Tagh Fault [30,31]. Among these, the Qiaotianshan Fault and the Heweitan Fault control the distribution of the Mesozoic strata and Pb–Zn deposits [16,17,20]. The Qiaotianshan Fault Zone is approximately 650 km long and 100 to 500 m wide, dipping northeast with an angle of 50° to 65° [32]. The fault zone experienced two phases of activity: an early phase of brittle–ductile shear extensional strike-slip tectonics and a later phase of brittle thrust strike-slip tectonics [27]. The Heweitan Fault Zone is approximately 210 km long, trends at approximately 300°, with a dip angle of 30°. The early phase was characterized by thrusting, with later superimposed extensional features [32]. Regional folding mainly developed during the Yanshanian and Indo–Chinese epochs. The Indo–Chinese epoch is characterized by a series of gentle, symmetrical NEE-trending folds observed in the southern part of the ore concentration area affecting the Triassic and older strata, with an angular unconformity between the Triassic and Jurassic strata. The Yanshanian folds are NW-trending, linear, asymmetrical, and tight, observed in the Cretaceous and older strata [29].

Magmatic activity in the Aksai Chin region is unevenly distributed. Extensive Late Triassic magmatic intrusions occur in the northern part of the region [33,34,35], while a few outcrops of mafic magmatic rocks are found in the central region, and a small number of volcanic interlayers are observed within the Jurassic limestone in the southern part [27,36].

3. Deposit Geology

The Sachakou Pb–Zn deposit is located in the south-central part of the Aksai Chin region. The exposed strata include the Upper Triassic Keleqinghe Formation (T₃k), Lower Jurassic Bagongbulansha Formation (J₁b), and Quaternary (Q) (Figure 2). Additionally, a small outcrop of the Early Triassic tuffite is found in the southwestern part of the mining area, representing a transitional facies between medium-grained lithic sandstone and rhyolitic tuff [37]. The Upper Triassic Keleqinghe Formation (T₃k) is distributed in the northern part of the mining area, characterized by gray to reddish-purple, thin- to medium-bedded siltstone, feldspathic quartz sandstone, and lithic quartz sandstone. The Lower Jurassic Bagongbulansha Formation (J₁b), which extends nearly east–west across the entire area, serves as the main ore-hosting formation. Its lithological assemblage mainly consists of gray-yellow to reddish-purple conglomerate, light to dark gray bioclastic limestone, fine-grained limestone, silicified limestone, and siliceous rock. The conglomerate is primarily composed of gravel and cement. The gravel particles, ranging in size from 2 to 11 mm, exhibit subangular to subrounded shapes and consist predominantly of tuff, fine sandstone, and limestone. The cement is chiefly composed of iron oxides, including goethite and hematite, occurring in a ferruginous cementation form. Within the limestone, multiple gypsum layers are present, with thicknesses varying between 0.1 and 1 m. The siliceous rock is primarily composed of chalcedony, which is typically formed by microcrystalline to cryptocrystalline quartz with particle sizes smaller than 0.05 mm.

In the mining area, a total of nine faults (F2–F10) have been identified. Among these, F4 and F5 form a set of nearly east–west normal faults that control the distribution of the main ore belt, while the other faults comprise several sets of nearly north–south and northwest-trending strike-slip faults.

No magmatic or metamorphic activity has been observed in the mining area.

Three Pb–Zn ore belts have been delineated in the Sachakou mining area. Ore belt III is the main ore belt, approximately 3100 m long and averaging 400 m in width, located between the east–west main fault and north–south secondary faults, with its orientation and occurrence strictly controlled by faulting. A total of 29 Pb–Zn ore bodies, including 15 concealed ones, have been delineated within ore belt III. The ore bodies are mostly stratiform-like or lenticular, occurring in the fracture zones of the siliceous rock and silicified limestone of the Lower Jurassic Bagongbulansha Formation (Figure 3 and Figure 4a,b). They exhibit average Zn grades ranging from 2.49% to 5.59%, average Pb grades ranging from 0.11% to 2.83%, and average Pb + Zn grades ranging from 3.67% to 7.27%.

The metallic minerals of the Sachakou Pb–Zn deposit are categorized into primary and secondary types. The primary minerals are dominated by sphalerite and galena, followed by stibnite, with minor amounts of pyrite and trace amounts of chalcopyrite (Figure 4e and Figure 5c). The secondary minerals are primarily smithsonite, followed by cerussite, limonite, hematite, and minor gypsum, among others (Figure 4f and Figure 5g). Gangue minerals are mainly quartz, with trace amounts of calcite and dolomite. The wall rock alteration is primarily silicification, with minor carbonate alteration.

Based on the mineral assemblage characteristics and paragenesis, the Sachakou Pb–Zn deposit can be divided into a hydrothermal period and a supergene oxidation period, with the hydrothermal period comprising one pre-mineralization stage and three mineralization stages (Figure 6).

Pre-mineralization stage (S0): This stage is characterized by barren quartz, predominantly occurring as vein structures, which are later infilled or crosscut and fragmented into breccia by S1 ores (Figure 4c,d).

Red–brown sphalerite mineralization stage (S1): This stage is characterized predominantly by vein mineralization. The primary minerals are mainly quartz and sphalerite, with subordinate galena, minor pyrite and calcite, and trace amounts of chalcopyrite (Figure 4e). Sphalerite is red–brown, occurring as anhedral to subhedral grains (0.06–3.60 mm), typically forming vein-like aggregates (Figure 5a). Galena occurs mostly as anhedral grains (0.02–2.20 mm), commonly exhibiting replacement textures and filling microveins along sphalerite and wall rock fractures (Figure 5b). Pyrite occurs as anhedral to subhedral grains (0.02–0.20 mm), typically filling sphalerite fractures or being disseminated throughout (Figure 5c).

Light-brown sphalerite mineralization stage (S2): This stage is also characterized predominantly by vein mineralization. The main minerals include sphalerite, galena, stibnite, and quartz, with minor calcite and trace amounts of pyrite. The S2 mineralization postdates S1, as evidenced by the S2 veins crosscutting and disrupting the S1 veins (Figure 4h,i and Figure 5d). Sphalerite occurs as light-brown anhedral grains (0.04–2.60 mm) (Figure 4k and Figure 5e). Stibnite is silver-gray to light gray, anhedral to subhedral prismatic grains (0.12–9.60 mm), commonly forming radiating and vein-like aggregates, often cementing siliceous rock breccia (Figure 4g and Figure 5f). Galena occurs as anhedral grains (0.02–2.80 mm), filling interstitial spaces between the sphalerite and the wall rock (Figure 5e).

Galena mineralization stage (S3): This stage is primarily characterized by brecciated ores. The S3 mineralization postdates S2, as evidenced by compressional interactions between S3 ores and pre-existing S2 veins, resulting in deformation and fragmentation of the latter (Figure 4j). The main mineral is galena, with minor sphalerite and stibnite (Figure 4l). Galena occurs as anhedral grains (0.04–5.60 mm), forming aggregates that fill spaces between breccia fragments (Figure 5g,h). Sphalerite is yellow, occurring as anhedral grains (0.01–0.13 mm), typically forming microvein-like aggregates (Figure 5i).

4. Sampling and Analytical Methods

All the samples in this study were collected from surface outcrops and drill cores of Ore Belt III in the Sachakou Pb–Zn deposit (Figure 2 and Figure 3). The samples were prepared into thin sections, polished sections, probe sections, and laser ablation sections. Sulfide minerals from different mineralization stages were selected under the microscope for observation, photography, and labeling in preparation for in situ trace element analysis and in situ S–Pb isotopic analysis.

4.1. In Situ Trace Element Analysis of Sphalerite

In situ trace element analysis of sphalerite was conducted at Xi’an Zhaonian Mineral Testing Technology Co., Ltd. (Xi’an, China), using a Thermo Fisher iCAP RQ ICP-MS (Thermo Fisher Scientific, Bremen, Germany) coupled with a New Wave NWR 213 laser ablation system (Electro Scientific Industries, Fremont, CA, USA). Laser ablation was performed with a spot diameter of 40 µm, a frequency of 8 Hz, and an energy density of approximately 6 J/cm², with high-purity helium as the carrier gas. The instrument was tuned to optimal conditions using NIST 610 before the analysis. LA-ICP-MS sampling was performed using single-spot ablation. During the analysis, the laser beam was initially blocked for 20 s to collect a blank background, followed by continuous ablation of the sample for 45 s, and then a 20 s washout to clean the introduction system, resulting in a total analysis time of 85 s per spot. Offline data processing was performed using Iolite 4 [39], with trace element compositions of minerals calibrated against MASS-1 and NIST 610. During the in situ trace element analysis of sphalerite, the zinc content measured by electron probe microanalysis (EPMA) was preferentially used as the internal standard. In the absence of EPMA data, a theoretical value of 64.06% was applied. The recommended values for elements in NIST 610 glass were obtained from the GeoReM database (http://georem.mpch-mainz.gwdg.de/ (access on 11 January 2022).

4.2. In Situ Sulfur Isotope Analysis of Sulfides

In situ S isotope analysis of sulfides was conducted at the State Key Laboratory of Continental Dynamics, Northwest University (Xi’an, China), using laser ablation-multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). The laser ablation system used was a Resonitics M50-LR excimer ArF laser ablation system (wavelength, 193 nm; pulse width, 20 ns) manufactured by Australian Scientific Instruments (ASI), Canberra, Australia, and the mass spectrometer was a Nu Plasma 1700 high-resolution multi-collector ICP-MS produced by Nu Instruments, Wrexham, UK. During the analysis, single-spot ablation was performed on predefined areas of the sample using the laser ablation system, with an ablation diameter of 30–37 µm, a frequency of 3 Hz, and an energy density of 3.6 J/cm². The aerosol generated by ablation was carried by high-purity helium (280 mL/min) into the MC-ICP-MS for analysis, with argon (0.86 L/min) as the auxiliary gas. Faraday cups H5, Ax, and L4 were used to collect signals for ³⁴S, ³³S, and ³²S, respectively. By adjusting the source slit, X–Y slit, and the adjustable collector slit in front of the Faraday cups, a resolution power greater than 20,000 was achieved. The reference materials used for analysis included sphalerite (NBS123, δ³⁴S_V-CDT = 17.8 ± 0.2‰, 2SD), pyrite (Py-4, δ³⁴S_V-CDT = 1.7 ± 0.3‰, 2SD), chalcopyrite (Cpy-1, δ³⁴S_V-CDT = 4.2 ± 0.3‰, 2SD), and galena (CBI-3, δ³⁴S_V-CDT = 28.5 ± 0.4‰, 2SD). Data acquisition was performed in the TRA mode, with an integration time of 0.2 s, background collection time of 30 s, sample integration time of 50 s, and washout time of 45 s. The standard-sample bracketing (SSB) method was used for correction during the analysis. Detailed analytical methods were described by Chen et al. [40] and Yuan et al. [41].

4.3. In Situ Lead Isotope Analysis of Sulfides

In situ Pb isotope analysis of sulfides was conducted at Xi’an Zhaonian Mineral Testing Technology Co., Ltd. (Xi’an, China), using laser ablation-multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). The laser ablation system used was a Geolas HD excimer laser ablation system manufactured by Coherent, Göttingen, Germany, and the mass spectrometer was a Neptune Plus multi-collector ICP-MS produced by Thermo Fisher Scientific, Bremen, Germany. During the analysis, single-spot ablation was performed on predefined areas of the sample using the laser ablation system, with the laser spot size and ablation frequency adjusted based on Pb signal intensity, typically ranging from 44 to 90 µm and 4 to 10 Hz, respectively, with an energy density of 5.0 J/cm². The analysis process was equipped with a signal smoothing and “de-mercury” device, which not only improved signal stability and precision of isotope ratio measurements, but also effectively reduced gas background and Hg signals from the sample, ensuring accurate determination of ²⁰⁴Pb [42]. The Neptune Plus mass spectrometer is equipped with nine Faraday cups, capable of simultaneously receiving static signals for ²⁰⁸Pb, ²⁰⁷Pb, ²⁰⁶Pb, ²⁰⁴Pb, ²⁰⁵Tl, ²⁰³Tl, and ²⁰²Hg. A single-standard Tl solution was introduced through a desolvation membrane (Aridus II) and mixed with the laser ablation aerosol before entering the ICP, using the ²⁰⁵Tl/²⁰³Tl ratio for real-time instrumental mass fractionation correction of the Pb isotopes. MASS-1 and Sph-HYLM (a natural sphalerite) were used to determine the mass fractionation relationship between Tl and Pb, yielding an optimized and matrix-matched ²⁰⁵Tl/²⁰³Tl ratio. Sphalerite standard Sph-HYLM was used as an external standard to monitor the precision and accuracy of the analysis, with long-term accuracy of ²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁶Pb/²⁰⁴Pb generally better than ±0.2‰ and external precision better than 0.4‰ (2σ). Detailed instrumental conditions and analytical methods were described by Zhang et al. [43], and the analytical data were processed using specialized isotope data processing software Iso-Compass (Ver. 1.0) [44].

5. Analysis Results

5.1. Trace Element Composition

This study analyzed 12 sphalerite samples from Sachakou, with a total of 69 points for in situ trace element analysis. The elemental composition characteristics are presented in Figure 7 and Table S1.

The Fe concentration in sphalerite ranges from 0.48% to 18.75%, with a predominant distribution between 3.46% and 7.21% and an average of 5.75%. In Sp1, the Fe concentration ranges from 5.52% to 18.75%, with an average of 9.97%, indicating a classification as marmatite. In Sp2, the Fe concentration varies from 0.73% to 7.95%, with an average of 4.59%, while in Sp3, it ranges from 0.48% to 7.55%, averaging 4.20%. The Cd concentration in sphalerite ranges from 677.35 ppm to 3395.79 ppm, predominantly between 991.84 ppm and 2063.62 ppm, averaging 1600.52 ppm. The Hg concentration ranges from 134.89 ppm to 1823.30 ppm, primarily distributed between 238.76 ppm and 554.78 ppm, with an average of 441.04 ppm. The Sb concentration ranges from 0.21 ppm to 5378.68 ppm, predominantly between 12.04 ppm and 507.19 ppm, with an average of 535.10 ppm. The Ag concentration varies from 0.52 ppm to 4143.41 ppm, mainly between 7.32 ppm and 67.07 ppm, with an average of 290.56 ppm. The Ga concentration ranges from 0.07 ppm to 714.21 ppm, primarily distributed between 1.58 ppm and 31.44 ppm, averaging 34.31 ppm. The Ge concentration ranges from 0.26 ppm to 280.33 ppm, predominantly between 1.80 ppm and 44.77 ppm, with an average of 34.78 ppm.

The Pb concentration in sphalerite ranges from 0.50 ppm to 13,316.11 ppm, predominantly between 14.72 ppm and 295.26 ppm, with an average of 483.92 ppm. The Cu concentration ranges from 2.08 ppm to 3949.51 ppm, primarily between 41.31 ppm and 575.02 ppm, averaging 448.36 ppm. The Co concentration spans from 3.41 ppm to 694.95 ppm, mainly between 26.37 ppm and 162.88 ppm, averaging 127.59 ppm. The Sn concentration ranges from 0.59 ppm to 799.69 ppm, primarily between 2.77 ppm and 12.34 ppm, averaging 35.94 ppm. The Se concentration ranges from 0.25 ppm to 91.27 ppm, primarily between 1.58 ppm and 9.17 ppm, averaging 7.72 ppm. The As concentration spans 0.01 ppm to 78.68 ppm, typically between 0.60 ppm and 3.08 ppm, averaging 6.44 ppm. The Tl concentration ranges from 0.00 ppm to 5.69 ppm, predominantly between 0.03 ppm and 0.46 ppm, averaging 0.42 ppm. Sphalerite also contains trace amounts of Mn, Ni, In, Au, Mo, and Bi.

5.2. In Situ Sulfur Isotopes

In situ S isotope analysis was conducted on 28 points across six metal sulfide samples from Sachakou, including 7 sphalerite, 9 galena, 7 stibnite, and 5 stratiform pyrite points (Table S2).

The δ³⁴S_V-CDT values of sulfides in the deposit samples vary from −4.93‰ to 1.24‰, with an average of −2.88‰ and a total range of 6.09‰. In S1, the δ³⁴S_V-CDT values for sphalerite (Sp1) range from 0.56‰ to 1.24‰, with an average of 0.90‰. Galena (Gn1) values range from −3.90‰ to −3.60‰, averaging −3.76‰. In S2, sphalerite (Sp2) δ³⁴S_V-CDT values range from −3.04‰ to −2.33‰, averaging −2.80‰. Galena (Gn2) values range from −4.49‰ to −4.01‰, with an average of −4.30‰. Stibnite (Sbn1) values range from −2.20‰ to −1.44‰, with an average of −1.74‰. In S3, sphalerite (Sp3) δ³⁴S_V-CDT values range from −4.61‰ to −3.70‰, averaging −4.16‰. Galena (Gn3) values span from −4.93‰ to −4.85‰, with an average of −4.89‰. Stibnite (Sbn2) δ³⁴S_V-CDT values range from −2.50‰ to −1.33‰, averaging −2.06‰. For stratiform pyrite, δ³⁴S_V-CDT values range from −2.76‰ to 5.22‰, with an average of 1.63‰.

5.3. In Situ Lead Isotopes

A total of 36 points from six galena samples collected in Sachakou were analyzed for in situ Pb isotopes (Table S3).

The Pb isotope ratios in these samples range from 18.308 to 18.395 for ²⁰⁶Pb/²⁰⁴Pb, from 15.669 to 15.731 for ²⁰⁷Pb/²⁰⁴Pb, and from 38.595 to 38.776 for ²⁰⁸Pb/²⁰⁴Pb, with averages of 18.345, 15.697, and 38.675, respectively. Calculated from these ratios, the µ value averages 9.66, the ω value averages 38.79, and the Th/U ratio averages 3.89. In S1, the ratios for galena (Gn1) are from 18.329 to 18.347 for ²⁰⁶Pb/²⁰⁴Pb, from 15.708 to 15.725 for ²⁰⁷Pb/²⁰⁴Pb, and from 38.694 to 38.749 for ²⁰⁸Pb/²⁰⁴Pb, with averages of 18.339, 15.717, and 38.726, respectively. In S2, the ratios for galena (Gn2) range from 18.349 to 18.395 for ²⁰⁶Pb/²⁰⁴Pb, from 15.679 to 15.731 for ²⁰⁷Pb/²⁰⁴Pb, and from 38.628 to 38.776 for ²⁰⁸Pb/²⁰⁴Pb, with averages of 18.369, 15.701, and 38.688, respectively. In S3, the ratios for galena (Gn3) range from 18.308 to 18.318 for ²⁰⁶Pb/²⁰⁴Pb, from 15.669 to 15.671 for ²⁰⁷Pb/²⁰⁴Pb, and from 38.595 to 38.614 for ²⁰⁸Pb/²⁰⁴Pb, with averages of 18.313, 15.670, and 38.605, respectively.

6. Discussion

6.1. Trace Element Distribution Characteristics and Implications for Mineralization Temperature

In the LA-ICP-MS signal intensity profiles of the sphalerite from the Sachakou deposit, metal elements Fe, Co, Zn, Cd, Hg, and Ag display relatively smooth ablation curves (Figure 8a), whereas Sn and In exhibit pronounced peaks (Figure 8b). These observations suggest that divalent cations such as Fe, Cd, Co, and Hg are incorporated into sphalerite via isomorphous substitution, monovalent cations such as Ag—through coupled substitution with trivalent cations, whereas Sn and In are likely present as inclusions [4,5,9,45].

In the bivariate scatter plots of trace elements in sphalerite (Figure 9a–d), although the correlations between Fe, Mn (with one anomalously high value > 2000 ppm removed), Co, Cd, and Ge are weak, these elements exhibit observable evolutionary trends across the three mineralization stages (Sp1 → Sp2 → Sp3): the concentrations of Fe, Mn, and Co decrease progressively, while those of Cd and Ge increase. Correspondingly, the color of sphalerite transitions from reddish-brown to light brown and then to yellow, dark-colored sphalerite is enriched in Fe, Co, and Mn, whereas light-colored sphalerite is enriched in Cd and Ge but relatively depleted in Fe, Co, and Mn. These characteristics suggest that (1) Fe²⁺ and Cd²⁺ in sphalerite are not simply negatively correlated in a binary manner, but are related to multiple factors in the fluid, such as the activity of reduced sulfur, pH, Zn/Cd ratio, fluid temperature, and the source of cadmium [8,46,47,48]; (2) Fe, Co, and Mn are more easily enriched under early mineralization and high-temperature conditions, while Ge and Cd are enriched under late mineralization and low-temperature conditions, with low temperatures favoring the enrichment of Ge and Cd [10,49,50,51]. The concentrations of In and Sn are extremely low, with median values of 0.03 × 10⁻⁶ and 4.18 × 10⁻⁶. These elements exhibit prominent synchronous peaks in laser ablation signal intensity profiles of some sphalerite samples (Figure 8b) and show a significant positive correlation in scatter plots (Figure 9e). It is inferred that In and Sn primarily enter sphalerite in the form of microscopic inclusions. Given the absence of magmatic rocks in the deep and peripheral regions of the Sachakou Pb–Zn deposit, it is inferred that In and Sn were likely derived from the extraction of acidic magmatic or pyroclastic rocks by ore-forming fluids during long-distance migration, eventually being concentrated in sphalerite [52]. In this analysis, 81% of the sphalerite samples have Ni concentrations below the detection limit. However, the remaining data reveal a strong positive correlation between Ni and Mn (R² = 0.80, Figure 9f), suggesting the possibility of a substitution mechanism: 2Zn²⁺ ↔ Ni²⁺ + Mn²⁺. Additionally, a strong positive correlation is also observed between As and Ag (R² = 0.93, Figure 9g), indicating a potential substitution mechanism: 2Zn²⁺ ↔ Ag⁺ + As³⁺ [53,54,55]. The trace element distribution patterns in the sphalerite from the Sachakou Pb–Zn deposit suggest that its mineralization process is weakly associated with magmatic activity and occurred in an environment characterized by progressive cooling.

Numerous studies have demonstrated that many trace elements (e.g., Mn, Fe, Ga, Ge, In, Ag, Cd, Co, Cu) in sphalerite are closely associated with temperature intensity [4,10,11,12,56]. Frenzel et al. [11] proposed that Mn, Fe, Ga, Ge, and In can be used to reconstruct mineralization temperatures, leading to the development of the GGIMFis geothermometer. Applying this method to the Sachakou sphalerite, the calculated mineralization temperature ranges from 294 °C to 121 °C, classifying it as a medium- to low-temperature deposit (Figure 10). Across different mineralization stages, the temperature for S1 ranges from 294 °C to 206 °C, for S2—from 260 °C to 133 °C, and for S3—from 216 °C to 121 °C, indicating a progressive cooling trend throughout the mineralization process, consistent with the temperature trends inferred from sphalerite color changes and the concentrations of Fe, Co, and Mn. This result is consistent with the mineralization temperature ranges (291 °C to 119 °C, unpublished) determined for the Honghuangling Pb–Zn deposit in this study using a GGIMFis geothermometer. These findings suggest that Pb–Zn deposits along the Heweitang Fault in the Aksai Chin region share comparable ore-forming temperatures, characterized by medium- to low-temperature conditions.

6.2. Sulfur Sources

The δ³⁴S_V-CDT values of the metal sulfides from the Sachakou Pb–Zn deposit range from −4.93‰ to 1.24‰, which are similar to the δ³⁴S_V-CDT range of mantle-derived sulfur (from −3‰ to 3‰) [57] (Figure 11a). However, no magmatic rocks have been identified in the mining area to date. Furthermore, the Sachakou deposit lacks hydrothermal alteration minerals and is characterized by low concentrations of Mn, Co, In, and Sn, suggesting that magmatic processes are unlikely to have been the primary source of sulfur in this deposit.

Sulfur in an individual deposit or region may originate from a single or multiple sources, such as sulfate-bearing evaporites, connate seawater, diagenetic sulfides, sulfur-bearing organic material, H₂S reservoir gas, and reduced sulfur in anoxic basin waters [59,60]. The Aksai Chin region is widely characterized by the development of evaporites, such as gypsum, particularly in the Lower Jurassic Bagongbulansha Formation and the Middle Jurassic Longshan Formation, where multiple gypsum layers have been identified [28,36], some of which have reached an economically viable minable scale.

Dissolved gypsum in these strata can be reduced to H₂S mainly through two main processes: (1) bacterial sulfate reduction (BSR) at lower temperatures (≤100 °C), which is a slow process and can result in S isotope fractionation exceeding −40‰ [61]; and (2) thermochemical sulfate reduction (TSR) at higher temperatures (>100 °C), which rapidly generates substantial amounts of H₂S, causing a maximum negative shift of 20‰ in S isotope fractionation [62]. The reduction of sulfate to H₂S can be represented by the following reaction equation [63]:

Ca²⁺ + 2SO₄²⁻ + 2CH₄ + 2H⁺ → 2H₂S + CaCO₃ + 3H₂O + CO₂

In this equation, CH₄ represents a range of possible organic compounds or hydrocarbons, while SO₄ denotes dissolved sulfate, which may originate from shallow phreatic refluxing brines or from evaporitic sulfate minerals such as gypsum, glauberite, or anhydrite [63]. The H₂S produced through these processes subsequently reacts with metal ions in the ore-forming fluid to precipitate sulfide minerals [64,65]:

H₂S + M²⁺ → MS + 2H⁺ (M = Zn, Pb)

S isotope analyses of the Jurassic gypsum layers between Sachakou and Huoshaoyun show the δ³⁴S_V-CDT values ranging from 11.10‰ to 20.63‰, with an average value of 16.24‰ (Figure 11b) [19,28,29,58]. This value is 19.12‰ higher than the average δ³⁴S_V-CDT value of the metal sulfides from the Sachakou deposit (−2.88‰). Zhou [66] identified post-mineralization barren calcite veins in the Sachakou Pb–Zn deposit, which have been attributed to the interaction between gypsum and the ore-forming fluid.

Furthermore, the mineralization temperature of the Sachakou Pb–Zn deposit, determined using a GGIMFis geothermometer, ranges from 294 °C to 121 °C, which falls within the temperature range required for TSR and aligns with the expected S isotope fractionation pattern. Therefore, it is inferred that TSR played a dominant role in sulfur reduction and mineralization at Sachakou.

6.3. Lead Sources

In the ²⁰⁷Pb/²⁰⁴Pb versus ²⁰⁶Pb/²⁰⁴Pb tectonic model diagram (Figure 12a,b), all the Pb isotope datapoints for Gn1 and Gn2 in the Sachakou deposit plot appear above the upper crustal lead evolution line, while the six datapoints from Gn3 fall between the upper crustal evolution line and the orogenic belt lead evolution line, closely adjacent to the upper crustal lead evolution line. In the ²⁰⁸Pb/²⁰⁴Pb versus ²⁰⁶Pb/²⁰⁴Pb tectonic model diagram (Figure 12c,d), all the datapoints from Sachakou plot appear above the orogenic belt, near its boundary. According to Zhu [67], the ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb values in lead tectonic models are the most sensitive indicators of source region variations, while ²⁰⁶Pb/²⁰⁴Pb is more responsive to the timing of mineralization. They proposed that calculating ∆β and ∆γ using U–Th–Pb isotope compositions from ore lead provides a more effective means of tracing the source region. In the ∆β versus ∆γ tectonic environment classification diagram for Pb isotopes, all the datapoints are linearly arranged within the upper crustal range (Figure 12e). According to the calculations, the Th/U ratios for the galena in the Sachakou deposit range from 3.86 to 3.92 (with an average of 3.89), which is slightly higher than the global upper crustal average of 3.88 [68]. The µ values range from 9.61 to 9.72 (with an average of 9.66), exceeding the upper crustal µ value of 9.58 [19], further supporting an upper crustal origin.

The metals in hydrothermal deposits hosted in carbonate rocks may originate from either the surrounding strata or the underlying basement rocks through which the fluid flows [70,71]. The strata of the Tianshuihai Terrane, ranging from the Permian to the Cretaceous, exhibit elevated background levels of Pb, Zn, Hg, Cd, and Sb, with the Pb concentrations being 2.69 to 4.04 times higher than the average crustal abundance, and the Zn concentrations 1.35 to 2.67 times higher [27,36]. Lead isotope analyses of the Upper Triassic Keleqinghe Formation limestone, the Middle Jurassic Longshan Formation limestone, and the Upper Cretaceous Tielongtan Group limestone [19,66] indicate that the Pb isotope composition of the galena from the Sachakou deposit is consistent with that of the Jurassic Bagongbulansha Formation, which hosts the ore (Figure 12b,d). Overall, the narrow variation range and linear distribution of the Pb isotope ratios and parameters in both the Sachakou ore and its host rocks suggest that the lead involved in the mineralization process likely originated from a single source or underwent thorough mixing and homogenization.

Based on this analysis, we conclude that the ore-forming metals in the Sachakou deposit are derived from the upper crust.

6.4. Genetic Type of the Deposit

Previous studies showed that endogenic metallogenic processes occurring within a temperature range of 50–300 °C and at depths of 0–10 km are classified as “epizonogenism,” with the resultant deposit referred to as an epizonogenic hydrothermal deposit [1,2]. Based on this classification, these deposits can be divided into three main types [1,2]:

(1) Volcanic-hosted epizonogenic hydrothermal deposits (VHE or VHEH). These deposits occur in continental volcanic and subvolcanic rocks and are formed by magmatically driven, circulating meteoric hydrothermal fluids. These include primarily epithermal deposits of Au, Ag, Pb–Zn, Cu, and U, along with some nonmetallic deposits. Based on the characteristics of the ore-forming fluids, these deposits can be further subdivided into high-sulfidation and low-sulfidation types.

(2) Sedimentary-hosted epizonogenic hydrothermal deposits (SHE or SHEH). These deposits occur in sedimentary sequences and are formed by circulating meteoric hydrothermal fluids or activated basin brines. These include Carlin-type gold deposits, MVT Pb–Zn deposits, sandstone-hosted Cu and U deposits, Hg–Sb deposits, and some low-temperature dispersed element deposits.

(3) Seafloor hydrothermal sedimentary deposits (SFH). These deposits are formed by submarine hydrothermal exhalative processes occurring at the lithosphere–hydrosphere interface and are commonly known as massive sulfide deposits. Depending on the abundance of volcanic rocks within the host strata, these deposits can be further classified as VMS (or VHMS) and SEDEX types.

The Sachakou Pb–Zn deposit is situated within the Qiao’ertianshan–Linjitang foreland basin of the Tianshuihai Terrane. It occurs within the carbonate rocks of the Lower Jurassic Bagongbulansha Formation (J₁b). The deposit is structurally and stratigraphically controlled, with the ore bodies primarily occurring in stratiform-like and lenticular shapes. The ore formation significantly postdates the host rocks, displaying typical epigenetic mineralization characteristics. The ore is predominantly vein-type and breccia-structured, exhibiting an anhedral to euhedral granular texture. The primary ore minerals include sphalerite, galena, and stibnite, with quartz serving as the dominant gangue mineral. The alteration of surrounding rock is primarily characterized by silicification, reflecting fluid–rock interactions between the ore-forming fluids and the limestone [72].

The sphalerite in the Sachakou Pb–Zn deposit is relatively rich in Fe, Ga, Ge, Ag, Cd, and Sb, while being low in Mn, Ni, In, and Sn. This contrasts with the trace element composition of sphalerite in magmatically related Pb–Zn deposits (Fe > 10%, Mn > 0.1%, Co > 200 ppm, and Sn > 100 ppm) [4,8,51,52,73]. The relatively high Fe content in the sphalerite from the Sachakou deposit may be associated with the extensive presence of hematite and siderite in the regional strata from the Late Neoproterozoic to Early Cambrian and Permian to Triassic periods [74,75]. The GGIMFis geothermometer indicates mineralization temperatures ranging from 294 °C to 121 °C, suggesting that the Sachakou Pb–Zn deposit formed under medium- to low-temperature conditions. In situ S–Pb isotope analysis suggests that the sulfur source for mineralization was derived from Jurassic gypsum layers, while the ore-forming metals were primarily sourced from the upper crust.

Based on the geological and geochemical characteristics of the Sachakou Pb–Zn deposit, it formed under epizonogenism and is classified as a sedimentary-hosted epizonogenic hydrothermal deposit.

7. Conclusions

(1) The Sachakou Pb–Zn deposit can be divided into the hydrothermal period and the supergene oxidation period, with the hydrothermal period further subdivided into the pre-mineralization stage, the red–brown sphalerite mineralization stage, the light-brown sphalerite mineralization stage, and the galena mineralization stage.

(2) Trace element analysis of the sphalerite from the Sachakou Pb–Zn deposit indicates that the mineralization process is not associated with magmatic activity. Additionally, the mineralization temperature, determined using a GGIMFis geothermometer, ranges from 294 °C to 121 °C.

(3) Sulfur isotope analysis reveals that the δ³⁴S_V-CDT values of the metal sulfides in the Sachakou deposit range from −4.93‰ to 1.24‰, indicating Jurassic gypsum layers as the sulfur source.

(4) The ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb ratios in the galena from the Sachakou deposit range from 18.308 to 18.395, from 15.669 to 15.731, and from 38.595 to 38.776, respectively, with the average values of 18.345, 15.697, and 38.675. These ratios indicate that the ore-forming metals are primarily crustal in origin.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/min15030271/s1, Table S1: Trace element composition of the sphalerite from the Sachakou Pb–Zn Deposit; Table S2: Sulfur isotope composition of the Sachakou Pb–Zn Deposit and its surrounding area; Table S3: Lead isotope compositions of the Sachakou Pb–Zn Deposit.

Author Contributions

Investigation, X.Z., N.L., T.F., J.S., Q.S., H.Z., Z.G., K.W. and J.W.; writing—original draft preparation, X.Z.; writing—review and editing, N.L. and Y.C.; supervision, Y.C. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Second Tibetan Plateau Scientific Expedition and Research Program (2021QZKK0303), the Tianshan Talents Project of the Xinjiang Uygur Autonomous Region (2023TSYCLJ0007), the National Natural Science Foundation of China (42372115 and 92055314), the Shaanxi Provincial Key R&D Program—International Science and Technology Cooperation Program—Key Project (2024GH-ZDXM-26), China Geological Survey Project (DD20240114), and the China Scholarship Council (202108575005).

Data Availability Statement

The authors declare that all analytical data supporting the findings of this study are available within the paper or cited in peer-review references.

Acknowledgments

Special thanks to Ming Wang, Baotong Feng, and Zuo Yan from the No. 8 Geological Party, Geological Bureau of the Xinjiang Uyghur Autonomous Region; Dong Liang from the Xinjiang Geological Exploration Institute, China Metallurgical Geology Bureau; and Zhaofei Wang from Zijin Mining Group Company Limited, as well as Wei Li from the Xi’an Center, China Geological Survey, for their invaluable assistance during the fieldwork. We also thank the reviewers for their valuable comments and suggestions, and the editor for their valuable improvements to the manuscript.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 2. Simplified geological map of the Sachakou Pb–Zn mining area (modified after Wang et al. [38]).

Figure 3. The profile of exploration line 317 in the Sachakou Pb–Zn Mining Area (modified after Wang et al. [38]).

Figure 4. Photographs of the Sachakou mining area and typical ore samples. (a) Overview of Pb–Zn ore belt III. (b) Contact boundary between silicified limestone and the silicified and limonitized fracture zone. (c) Banded Pb–Zn ore. (d) Brecciated quartz (S0) cemented by the Pb–Zn ore (S1). (e) Partially oxidized vein-type Pb–Zn ore (S1). (f) Fully oxidized vein-type Pb–Zn ore. (g) Vein-type stibnite ore (S2). (h) Pb–Zn ore (S2) cementing breccias of the Pb–Zn ore (S1) and siliceous rock fragments. (i) Sphalerite vein (S2) crosscutting a sphalerite vein (S1) and the siliceous rock. (j) Contact relationship between the Pb–Zn ore (S2) and the Pb–Zn ore (S3). (k) Vein-type Pb–Zn ore (S2). (l) Brecciated galena ore (S3). Cer—cerussite; Gn—galena; Gyp—gypsum; Lm—limonite; Qz—quartz; Sbn—stibnite; Smt—smithsonite; Sp—sphalerite.

Figure 5. Photomicrographs and BSE images of ore minerals from the Sachakou Pb–Zn deposit. (a) Rhythmic banded Sp1 coexisting with Qz1. (b) Qz1 coexisting with Gn1 and Sp1. (c) Qz1 coexisting with Py1, Sp1, and Gn1, with smithsonite replacing Sp1 along fractures. (d) Qz1 and Sp1 crosscut by later-stage Qz2 and Sp2. (e) Gn2 filling fractures within Sp2 in the siliceous rock. (f) Sbn1 coexisting with Sp2, with euhedral Py2 developing along the boundary between Sbn1 and the siliceous rock. (g) Anglesite and cerussite replacing the edges of Gn3. (h) Cerussite replacing Gn3 (BSE); (i) Siderite coexisting with Sp3 and Gn3, with cerussite developing along the fractures within siderite and Gn3 (BSE). Ang—anglesite; Cer—cerussite; Gn—galena; Py—pyrite; Qz—quartz; Sd—siderite; Sbn—stibnite; Smt—smithsonite; Sp—sphalerite.

Figure 6. Mineralization stage division of the Sachakou Pb–Zn deposit.

Figure 7. Comparison of the sphalerite trace element concentrations using LA-ICP-MS in the Sachakou Pb–Zn deposit.

Figure 8. Representative time-resolved depth profiles of the sphalerite from the Sachakou Pb–Zn deposit. (a) Flat signals indicating elements mainly hosted in the sphalerite lattice. (b) Abnormal peak signals suggesting the presence of micro-scale mineral inclusions.

Figure 9. Scatter plot of trace elements in the sphalerite from the Sachakou Pb–Zn deposit. (a) Fe vs. Mn. (b) Fe vs. Co. (c) Fe vs. Ge. (d) Fe vs. Cd. (e) In vs. Sn. (f) Ni vs. Mn. (g) As vs. Ag.

Figure 10. Histogram of sphalerite mineralization temperatures in the Sachakou Pb–Zn deposit, determined using a GGIMFis geothermometer.

Figure 11. Sulfur isotope histogram (a) and scatter plot (b) of the sulfides from the Sachakou Pb–Zn deposit and the surrounding area (Jurassic gypsum layer data from the research by Gao et al. [29], Jia et al. [19], Li et al. [58]; Tang et al. [28]).

Figure 12. Pb isotope correlation diagrams of the galena from the Sachakou Pb–Zn Deposit. The ²⁰⁷Pb/²⁰⁴Pb versus ²⁰⁶Pb/²⁰⁴Pb evolution diagram (base map from Zartman and Doe [69]) is shown in (a), with a close-up view provided in (b); the ²⁰⁸Pb/²⁰⁴Pb versus ²⁰⁶Pb/²⁰⁴Pb evolution diagram (base map from Zartman and Doe [69]) is shown in (c), with a close-up view provided in (d); (e) ∆β versus ∆γ tectonic environment classification diagram (base map from Zhu [67]). The stratigraphic Pb isotope data in (a–e) are cited from Jia et al. [19] and Zhou [66]. 1—mantle-derived lead; 2—upper crustal lead; 3—subduction zone lead with a mixture of upper crustal and mantle-derived lead (3a—magmatism; 3b—sedimentation); 4—chemically precipitated lead; 5—seafloor hydrothermal lead; 6—medium- to high-grade metamorphic lead; 7—high-grade lower crustal lead; 8—orogenic belt lead; 9—ancient shale upper crustal lead; 10—retrograde metamorphic lead.

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Zhao, X.; Li, N.; Fan, T.; Sun, J.; Sui, Q.; Zhang, H.; Guo, Z.; Wusiman, J.; Weng, K.; Chen, Y. Geochemical Study of Trace Elements and In Situ S–Pb Isotopes of the Sachakou Pb–Zn Deposit in the Aksai Chin Region, Xinjiang. Minerals 2025, 15, 271. https://doi.org/10.3390/min15030271

AMA Style

Zhao X, Li N, Fan T, Sun J, Sui Q, Zhang H, Guo Z, Wusiman J, Weng K, Chen Y. Geochemical Study of Trace Elements and In Situ S–Pb Isotopes of the Sachakou Pb–Zn Deposit in the Aksai Chin Region, Xinjiang. Minerals. 2025; 15(3):271. https://doi.org/10.3390/min15030271

Chicago/Turabian Style

Zhao, Xiaojian, Nuo Li, Tingbin Fan, Jing Sun, Qinglin Sui, Huishan Zhang, Zhouping Guo, Jianatiguli Wusiman, Kai Weng, and Yanjing Chen. 2025. "Geochemical Study of Trace Elements and In Situ S–Pb Isotopes of the Sachakou Pb–Zn Deposit in the Aksai Chin Region, Xinjiang" Minerals 15, no. 3: 271. https://doi.org/10.3390/min15030271

APA Style

Zhao, X., Li, N., Fan, T., Sun, J., Sui, Q., Zhang, H., Guo, Z., Wusiman, J., Weng, K., & Chen, Y. (2025). Geochemical Study of Trace Elements and In Situ S–Pb Isotopes of the Sachakou Pb–Zn Deposit in the Aksai Chin Region, Xinjiang. Minerals, 15(3), 271. https://doi.org/10.3390/min15030271

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