Pb-Zn Deposits and Associated Critical Metals

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Deposits".

Deadline for manuscript submissions: closed (16 June 2023) | Viewed by 19162

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Guest Editor
Key Laboratory of Critical Minerals Metallogeny in Universities of Yunnan Province, School of Earth Sciences, Yunnan University, Kunming 650500, China
Interests: MVT Pb-Zn deposits; carbonate minerals U-Pb dating; ore deposit geochemistry; critical metals; ore prospecting

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Guest Editor
MNR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China
Interests: Pb–Zn mineralization; metallogenesis; precipitation mechanism; enrichment of scattered elements
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Faculty of Land and Resources Engineering, Kunming University of Science and Technology, Kunming 650093, China
Interests: MVT Pb-Zn deposits; cassiterite–sulphide deposits; critical metals

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Guest Editor
College of Resources and Environment, Yangtze University, Wuhan 430100, China
Interests: carbonate-hosted Zn-Pb deposits; non-sulphide Zn-Pb deposit; critical metals

Special Issue Information

Dear Colleagues,

Pb-Zn deposits and the critical metals within them are critical for the functioning of human society. Pb-Zn deposits are heterogeneously distributed worldwide with varying deposit types, deposit scales and ore grades, and the types and contents of critical metals found in them differ as well. Pb-Zn deposit types include volcanic-hosted massive sulphide (VHMS/VMS), the magmatic–hydrothermal-associated skarn and/or epithermal type, sediment-hosted types (e.g., clastic-hosted sedimentary exhalative, SEDEX; carbonate-hosted Mississippi Valley type, MVT; sandstone-hosted type, SST; and shale-hosted type) and the vein type. Pb-Zn deposits also host economically valuable critical metals. For example, magmatic–hydrothermal-associated skarn and/or epithermal Pb-Zn deposits provide In and Cd, whereas sediment-hosted Pb-Zn deposits provide Ge, Cd, Ga and Tl. Although extensive studies have been carried out on these deposits, several important mechanisms remain unelucidated, including those underlying the detailed ore-forming process, the enrichment of Pb-Zn and associated critical metals and their genetic relationship and the occurrence of critical metals. To better understand the origin of Pb-Zn deposits and their affiliated critical metals, this Special Issue will report new advances in ore deposit geology, mineralogy, geochemistry, geochronology, ore prospecting, computational simulation, big data and deep learning. Papers detailing new analytical methods and experimental studies are also welcome. This Special Issue will present new studies spanning from the regional to mineral scale and from a variety of fields, from geology and geochemistry to ore prospecting, and from computational simulation to big data and deep learning, using novel advanced analytical techniques. It aims to provide a comprehensive understanding of Pb-Zn deposits and their associated critical metals.

Prof. Dr. Jia-Xi Zhou
Prof. Dr. Changqing Zhang
Prof. Dr. Tao Ren
Dr. Yue Wu
Guest Editors

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Keywords

  • Pb-Zn deposits
  • critical metals
  • sulphide minerals
  • hydrothermal carbonate minerals
  • mineral in situ geochemistry
  • geochronology
  • ore-forming process
  • ore prospecting
  • computational simulation
  • big data and deep learning

Published Papers (12 papers)

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Research

19 pages, 99506 KiB  
Article
Integration of Electrical Resistivity Tomography and Induced Polarization for Characterization and Mapping of (Pb-Zn-Ag) Sulfide Deposits
by Mosaad Ali Hussein Ali, Farag M. Mewafy, Wei Qian, Fahad Alshehri, Mohamed S. Ahmed and Hussein A. Saleem
Minerals 2023, 13(7), 986; https://doi.org/10.3390/min13070986 - 24 Jul 2023
Cited by 6 | Viewed by 1880
Abstract
The accurate characterization and mapping of low-grade ore deposits necessitate the utilization of a robust exploration technique. Induced polarization (IP) tomography is a powerful geophysical method for mineral exploration. An integrated survey using electrical resistivity tomography (ERT) and IP was employed in this [...] Read more.
The accurate characterization and mapping of low-grade ore deposits necessitate the utilization of a robust exploration technique. Induced polarization (IP) tomography is a powerful geophysical method for mineral exploration. An integrated survey using electrical resistivity tomography (ERT) and IP was employed in this study to characterize and map (Zn-Pb-Ag) ore deposits in NE New Brunswick, Canada. The survey encompassed twelve parallel lines across the study area. The 2D and 3D inversion of the results provided a detailed image of the resistivity and chargeability ranges of subsurface formations. The boundaries of sulfide mineralization were determined based on resistivity values of (700–2000 Ohm.m) and chargeability values of (3.5 mV/V) and were found to be located at an approximate depth of 80–150 m from the surface. The findings were validated through a comparison with data from borehole logs and mineralogy data analysis. The size and shape of sulfide deposits were successfully characterized and mapped in the study area using this cost-effective mapping approach. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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21 pages, 15511 KiB  
Article
Genesis of the Giant Huoshaoyun Non-Sulfide Zinc–Lead Deposit in Karakoram, Xinjiang: Constraints from Mineralogy and Trace Element Geochemistry
by Xiang Chen, Dengfei Duan, Yuhang Zhang, Fanyan Zhou, Xin Yuan and Yue Wu
Minerals 2023, 13(7), 842; https://doi.org/10.3390/min13070842 - 22 Jun 2023
Viewed by 1279
Abstract
The Huoshaoyun zinc–lead deposit, a giant non-sulfide deposit in Xinjiang, is one of the most significant discoveries of zinc–lead deposit in China and globally in recent years. The deposit is dominated by zinc–lead non-sulfides, with minor occurrences of sulfides such as sphalerite, galena, [...] Read more.
The Huoshaoyun zinc–lead deposit, a giant non-sulfide deposit in Xinjiang, is one of the most significant discoveries of zinc–lead deposit in China and globally in recent years. The deposit is dominated by zinc–lead non-sulfides, with minor occurrences of sulfides such as sphalerite, galena, and pyrite. The non-sulfide minerals include smithsonite, cerussite, anglesite, and Fe-oxide. This study focuses on the mineralogical characteristics of sulfide and non-sulfide ores, as well as the trace element characteristics of sphalerite, smithsonite, and Fe-oxide. Mineralogical analysis reveals that smithsonite is derived from the oxidation of primary sulfide minerals and can be classified into three types that are generated during different stages of supergene oxidation. The three types of smithsonite are formed through replacing the sphalerite and host limestone, as well as directly precipitating in the fissures and vugs. Trace element analysis of sphalerite indicates that it is rich in Cd, Tl, and Ge, but poor in Fe and Mn. The ore-forming temperature, calculated using the GGIMFis geothermometer, is mostly within the range of 100~150 °C. Moreover, the trace element characteristics, ore-forming temperature, and S and Pb isotope compositions of the sulfide ores of the Huoshaoyun deposit are similar to those of the Jinding and Duocaima MVT lead–zinc deposits, which are also located in the Eastern Tethyan zinc–lead belt. This suggests that the sulfide orebody in the Huoshaoyun Zn-Pb deposit could also be the MVT deposit. Study of the trace element of the non-sulfide minerals shows that the Mn and Cd are relatively enriched in smithsonite, while Ga, Ge, and Pb are enriched in Fe-oxide. This can be attributed to distinct geochemical properties of the trace elements in the non-sulfide minerals of the Huoshaoyun deposit and is consistent with those of the other oxidized MVT deposits, thus indicating the supergene oxidation process of this deposit. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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20 pages, 13670 KiB  
Article
LA-ICP-MS Trace Element Geochemistry of Sphalerite and Metallogenic Constraints: A Case Study from Nanmushu Zn–Pb Deposit in the Mayuan District, Shaanxi Province, China
by Junjie Wu, Huixin Dai, Yong Cheng, Saihua Xu, Qi Nie, Yiming Wen and Ping Lu
Minerals 2023, 13(6), 793; https://doi.org/10.3390/min13060793 - 10 Jun 2023
Cited by 1 | Viewed by 1177
Abstract
The Nanmushu Zn–Pb deposit is a large-scale and representative deposit in the Mayuan ore field on the northern margin of the Yangtze Block. This study investigates the trace element geochemistry of sphalerite from this deposit using laser ablation inductively coupled plasma mass spectrometry [...] Read more.
The Nanmushu Zn–Pb deposit is a large-scale and representative deposit in the Mayuan ore field on the northern margin of the Yangtze Block. This study investigates the trace element geochemistry of sphalerite from this deposit using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The results show that the main trace elements in sphalerite include various trace elements, such as Mn, Fe, Cu, Ga, Ge, Ag, Cd, Pb, Co, Hg, Tl, In, Sn, and Sb. Among them, Ag, Ge, Cd, and Cu are valuable components that may be recovered during mineral processing or smelting techniques. The histograms, LA-ICP-MS time-resolved depth profiles, and linear scan profiles indicated that most trace elements occur in sphalerite as isomorphs, while partial Pb, Fe, and Ag occur as tiny mineral inclusions. The correlation diagrams of trace elements revealed that Fe2+, Mn2+, Pb2+, and Tl3+ can substitute Zn2+ in sphalerite through isomorphism. In sphalerite, Cd2+ and Hg2+ together or Mn2+, Pb2+, and Tl3+ together can replace Zn2+, i.e., ((3Mn, 3Pb, 2Tl)6+, 3(Cd, Hg)2+) ↔ 3Zn2+. Moreover, there is a mechanism of Ge4+ with Cu+ or Ga3+ with Cu+ replacing Zn2+ in the Nanmushu deposit, i.e., Ge4+ + 2Cu+ ↔ 3Zn2+ or 2Ga3+ + 2Cu+ ↔ 4Zn2+. Furthermore, the trace element compositions indicate that the Nanmushu Zn mineralization occurred under low-temperature conditions (<200 °C) and should be classified as a Mississippi Valley-type (MVT) deposit. This study provides new insights into the occurrence and substitution mechanisms of trace elements in sphalerite and the metallogenic constraints of the Nanmushu deposit. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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17 pages, 6856 KiB  
Article
Zircon and Garnet U–Pb Ages of the Longwan Skarn Pb–Zn Deposit in Guangxi Province, China and Their Geological Significance
by Xuejiao Zhang, Wei Ding, Liyan Ma, Wei Fu, Xijun Liu and Saisai Li
Minerals 2023, 13(5), 644; https://doi.org/10.3390/min13050644 - 06 May 2023
Cited by 2 | Viewed by 1472
Abstract
Garnet is the most common alteration mineral in skarn-type deposits, and the geochronological research on it can limit the mineralization age. The Longwan Pb–Zn deposit, situated within the Fozichong Pb–Zn ore field in Guangxi, lacks precise geochronological data, limiting the in-depth comprehension of [...] Read more.
Garnet is the most common alteration mineral in skarn-type deposits, and the geochronological research on it can limit the mineralization age. The Longwan Pb–Zn deposit, situated within the Fozichong Pb–Zn ore field in Guangxi, lacks precise geochronological data, limiting the in-depth comprehension of its genesis and tectonic setting. This study employs LA-ICP-MS U–Pb dating of garnets developed in the skarn orebody and zircons in the associated granitic porphyry to determine the deposit’s mineralization age. Backscatter electron images and electron probe microanalysis reveal common zonation characteristics in garnets from the Longwan Pb–Zn deposit, with dominant end-member compositions of Andradite and Grossular. The values of U concentrations range from 1.8 ppm to 3.7 ppm, and a garnet U–Pb age of 102.6 ± 1.9 Ma was obtained, consistent with the zircon U–Pb age of 102.1 ± 1.2 Ma from the granite porphyry within the deposit. The Longwan Pb–Zn deposit formed during the late Early Cretaceous as a skarn deposit resulting from contact metasomatism between the granite porphyry and the host rock. The deposit likely formed in response to the Neo-Tethys plate subducting beneath the South China continent during the Cretaceous, followed by a retreat during the Late Cretaceous. The Cenxi-Bobai Fault experienced reactivation under the extensional tectonic regime induced by the Neo-Tethys Ocean’s retreat, leading to a series of magmatic activities along the NE-trending direction within the Fault. The Longwan Pb–Zn deposit formed during the processes of magma emplacement and contact metasomatic reactions with the country rock. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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20 pages, 4101 KiB  
Article
Trace Elements of Gangue Minerals from the Banbianjie Ge-Zn Deposit in Guizhou Province, SW China
by Yun-Lin An, Jia-Xi Zhou, Qing-Tian Meng, Guo-Tao Sun and Zhi-Mou Yang
Minerals 2023, 13(5), 638; https://doi.org/10.3390/min13050638 - 04 May 2023
Cited by 1 | Viewed by 1300
Abstract
There are many dispersed element-rich Pb-Zn deposits hosted by Paleozoic carbonate rocks in the Middle-Upper Yangtze Block, China. The origin and nature of the ore-forming fluids that formed them are still much debated (syngenetic vs. epigenetic). The Banbianjie Ge-Zn deposit is located in [...] Read more.
There are many dispersed element-rich Pb-Zn deposits hosted by Paleozoic carbonate rocks in the Middle-Upper Yangtze Block, China. The origin and nature of the ore-forming fluids that formed them are still much debated (syngenetic vs. epigenetic). The Banbianjie Ge-Zn deposit is located in the southeastern margin of the Yangtze Block, SW China. It is a newly discovered medium-sized Zn (Zn metal reserves > 0.39 Mt, @1.78%–9.5% Zn) and large-scale Ge deposit (Ge metal resources > 900 t, @100 × 10−6–110 × 10−6 Ge) in the Western Hunan–Eastern Guizhou Pb-Zn metallogenic belt, SW China. Gangue minerals in the Banbianjie deposit are very developed, including calcite, dolomite and barite, which are closely associated with sulfides. Hence, the trace elements of gangue minerals could be used to trace the nature, source and evolution of ore-forming fluids, and the ore genesis of this deposit can be discussed. These gangue minerals are nearly horizontally distributed in the plot of La/Ho-Y/Ho, suggesting that they are the products of the same hydrothermal fluids. The total rare earth element (∑REE) contents from calcite and dolomite to barite show an increasing trend, indicating that the REEs in the ore-forming fluids were mainly enriched in barite. Hence, the ∑REE of barite can approximately represent the ΣREE of the hydrothermal fluids, which are quite similar to those of the underlying strata, indicating that the ore-forming fluids were likely originated from and/or flowed through them. The Eu anomalies from dolomite (Eu/Eu* = 0.33–0.66) to calcite (Eu/Eu* = 0.29–1.13) and then to barite (Eu/Eu* = 1.64–7.71) show an increasing trend, suggesting that the ore-forming fluids experienced a shift in the ore-forming environment from reduced to oxidized. Hence, the source of the Banbianjie Ge-Zn deposit is the underlying strata, and the ore-forming physical–chemical condition has experienced a transition from reduction to oxidation during the Ge-Zn mineralization. The ore genesis of the Banbianjie Ge-Zn deposit is most likely a Mississippi Valley-type (MVT) deposit. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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12 pages, 9305 KiB  
Article
The Genesis of Pyrite in the Fule Pb-Zn Deposit, Northeast Yunnan Province, China: Evidence from Mineral Chemistry and In Situ Sulfur Isotope
by Meng Chen, Tao Ren and Shenjin Guan
Minerals 2023, 13(4), 495; https://doi.org/10.3390/min13040495 - 30 Mar 2023
Viewed by 1278
Abstract
The Fule deposit is a typical Cd-, Ge- and Ga-enriched Pb-Zn deposit located in the southeast of the Sichuan–Yunnan–Guizhou Pb-Zn polymetallic ore province in China. Zoned, euhedral cubic and pentagonal dodecahedral and anhedral pyrites were observed, and they are thought to comprise two [...] Read more.
The Fule deposit is a typical Cd-, Ge- and Ga-enriched Pb-Zn deposit located in the southeast of the Sichuan–Yunnan–Guizhou Pb-Zn polymetallic ore province in China. Zoned, euhedral cubic and pentagonal dodecahedral and anhedral pyrites were observed, and they are thought to comprise two generations. First generation pyrite (Py1) is homogeneous and entirely confined to a crystal core, whereas second generation pyrite (Py2) forms bright and irregular rims around the former. Second generation pyrite also occurs as a cubic and pentagonal dodecahedral crystal in/near the ore body or as an anhedral crystal generally closed to the surrounding rock. The content of S, Fe, Co, and Ni in Py1 are from 52.49 to 53.40%, 41.91 to 44.85%, 0.19 to 0.50% and 0.76 to 1.55%, respectively. The values of Co/Ni, Cu/Ni and Zn/Ni are from 0.22 to 0.42, 0.02 to 0.08 and 0.43 to 1.49, respectively, showing that the Py1 was formed in the sedimentary diagenetic stage. However, the contents of S, Fe, Co, and Ni in Py2 are in the range from 51.67 to 54.60%, 45.01 to 46.52%, 0.03 to 0.07% and 0.01 to 0.16%, respectively. The Co/Ni, Cu/Ni and Zn/Ni values of Py2 are from 0.40 to 12.33, 0.14 to 13.70 and 0.04 to 74.75, respectively, which is characterized by hydrothermal pyrite (mineralization stage). The different δ34S values of the Py1 (−34.9 to −32.3‰) and the Py2 (9.7 to 20.5‰) indicate that there are at least two different sources of sulfur in the Fule deposit. The sulfur in Py1 was derived from the bacterial sulfate reduction (BSR), whereas the sulfur in the ore-forming fluids (Py2) was derived from the thermochemical sulfate reduction (TSR). The main reasons for the different morphologies of pyrite in the regular spatial distribution in the Fule deposit are temperature and sulfur fugacity. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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24 pages, 26033 KiB  
Article
Pore Variation Characteristics of Altered Wall Rocks in the Huize Lead–Zinc Deposit, Yunnan, China and Their Geological Significance
by Yanglin Li, Zhigang Kong, Changqing Zhang, Yue Wu, Xue Yang, Yu Wang and Gang Chen
Minerals 2023, 13(3), 363; https://doi.org/10.3390/min13030363 - 04 Mar 2023
Cited by 2 | Viewed by 1478
Abstract
The porosity and permeability of the rock surrounding lead–zinc deposits are key factors for controlling the migration and precipitation of ore-forming hydrothermal fluid. In this paper, the Huize super-large lead–zinc deposit was taken as the case study, and variations in the porosity and [...] Read more.
The porosity and permeability of the rock surrounding lead–zinc deposits are key factors for controlling the migration and precipitation of ore-forming hydrothermal fluid. In this paper, the Huize super-large lead–zinc deposit was taken as the case study, and variations in the porosity and permeability of the wall rocks and their relationship with the orebody were analyzed by using CT scanning technology. The experimental results showed that the average pore radius of dolomite with a decreasing distance to the orebody ranged from 1.60 to 1.65 μm, increasing to 1.77~2.05 μm. The CT porosity increased from 2.76%–2.81% to 3.35%–3.99%. The average pore throat length decreased from 29.57–39.95 μm to 13.57–16.83 μm. In the research, it was found that the hydrothermal fluids rich in chemical elements changed the properties of the surrounding rocks. Temperature rise will lead to dolomitization of limestone and recrystallization of dolomite. This process led to an increase in the porosity of the wall rocks. During the formation of the orebody, the metal minerals in the hydrothermal fluid entered the pores of the rock. As a result, the pore radius and pore volume of the wall rocks were reduced, along with the pore throat radius and pore throat length. Therefore, the wall rock pores near the orebody were isolated from each other, and the permeability of the surrounding rock decreased. The variation characteristics for the porosity and permeability of the dolomite at various distances from the mine can be used to discover orebodies. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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16 pages, 6034 KiB  
Article
The Origin of the Caiyuanzi Pb–Zn Deposit in SE Yunnan Province, China: Constraints from In Situ S and Pb Isotopes
by Yongguo Jiang, Yinliang Cui, Hongliang Nian, Changhua Yang, Yahui Zhang, Mingyong Liu, Heng Xu, Jinjun Cai and Hesong Liu
Minerals 2023, 13(2), 238; https://doi.org/10.3390/min13020238 - 08 Feb 2023
Viewed by 1303
Abstract
Located at the intersection of the Tethys and Pacific Rim metallogenic belts, the Laojunshan polymetallic metallogenic province in SE Yunnan Province hosts many large-scale W–Sn and Sn–Zn polymetallic deposits. The newly discovered Caiyuanzi medium-sized Pb–Zn deposit is located in the northern part of [...] Read more.
Located at the intersection of the Tethys and Pacific Rim metallogenic belts, the Laojunshan polymetallic metallogenic province in SE Yunnan Province hosts many large-scale W–Sn and Sn–Zn polymetallic deposits. The newly discovered Caiyuanzi medium-sized Pb–Zn deposit is located in the northern part of this province and has eight sulfide ore bodies. All the ore bodies occur in the siliceous rocks of the Lower Devonian Pojiao Formation (D1p). The ore bodies are conformable with stratigraphy and controlled by a lithologic horizon. The sulfide ores have banded or laminated structures. The ore minerals are mainly pyrite, chalcopyrite, sphalerite, and galena. In this study, in situ sulfur and lead isotopes were used to constrain the origin of the Caiyuanzi Pb–Zn deposit. The results show that the in situ δ34S values of pyrite, chalcopyrite, and sphalerite range from 0.1‰ to 6.0‰, with an average of 4.7‰. This δ34S signature reflects the mixing between magmatic-derived and reduced seawater sulfate sulfur. The in situ Pb isotopes characteristics of pyrite, galena, and sphalerite suggest that the sulfur and lead of ore minerals come from the upper crust. Integrating the data obtained from the studies including regional geology, ore geology, and S–Pb isotope geochemistry, we proposed that the Caiyuanzi Pb–Zn deposit is a hydrothermal deposit formed by sedimentary exhalative and magmatic hydrothermal superimposition. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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18 pages, 5147 KiB  
Article
The Origin of Carbonate Components in Carbonate Hosted Pb-Zn Deposit in the Sichuan-Yunnan-Guizhou Pb-Zn Metallogenic Province and Southwest China: Take Lekai Pb-Zn Deposit as an Example
by Zhiwei He, Bo Li, Xinfu Wang, Xianguo Xiao, Xin Wan and Qingxi Wei
Minerals 2022, 12(12), 1615; https://doi.org/10.3390/min12121615 - 15 Dec 2022
Cited by 2 | Viewed by 1567
Abstract
The Lekai lead–zinc (Pb-Zn) deposit is located in the northwest of the Sichuan–Yunnan–Guizhou (SYG) Pb-Zn metallogenic province, southwest China. Even now, the source of the metallogenic fluid of Pb-Zn deposits in the SYG Pb-Zn metallogenic province has not been recognized. Based on traditional [...] Read more.
The Lekai lead–zinc (Pb-Zn) deposit is located in the northwest of the Sichuan–Yunnan–Guizhou (SYG) Pb-Zn metallogenic province, southwest China. Even now, the source of the metallogenic fluid of Pb-Zn deposits in the SYG Pb-Zn metallogenic province has not been recognized. Based on traditional lithography, rare earth elements (REEs), and carbon–oxygen (C–O) isotopes, this work uses the magnesium (Mg) isotopes of hydrothermal carbonate to discuss the fluid source of the Lekai Pb-Zn deposit and discusses the fractionation mechaism of Mg isotopes during Pb-Zn mineralization. The REE distribution patterns of hydrothermal calcite/dolomite are similar to that of Devonian sedimentary carbonate rocks, which are all present steep right-dip type, indicating that sedimentary carbonate rocks may be serve as the main source units of ore-forming fluids. The C–O isotopic results of hydrothermal dolomite/calcite and the δ13CPDB–δ18 OSMOW diagram show that dolomite formation is closely related to the dissolution of marine carbonate rocks, and calcite may be affected to some extent by basement fluid. The Mg isotopic composition of dolomite/calcite ranges from −3.853‰ to −1.358‰, which is obviously lighter than that of chondrites, mantle, or seawater and close to that of sedimentary carbonate rock. It shows that the source of the Mg element in metallogenic fluid of Lekai Pb-Zn deposit may be sedimentary carbonate rock rather than mantle, chondrites, or seawater. In addition, the mineral phase controls the Mg isotope fractionation of dolomite/calcite in the Lekai Pb-Zn deposit. Based on the geological, mineralogical, and hydrothermal calcite/dolomite REE, C–O isotope, and Mg isotope values, this work holds that the mineralization of the Lekai Pb-Zn deposit is mainly caused by basin fluids, influenced by the basement fluids; the participation of basement fluids affects the scale and grade of the deposit. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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16 pages, 4791 KiB  
Article
3D Quantitative Metallogenic Prediction of Indium-Rich Ore Bodies in the Dulong Sn-Zn Polymetallic Deposit, Yunnan Province, SW China
by Fuju Jia, Zhihong Su, Hongliang Nian, Yongfeng Yan, Guangshu Yang, Jianyu Yang, Xianwen Shi, Shanzhi Li, Lingxiao Li, Fuzhou Sun and Ceting Yang
Minerals 2022, 12(12), 1591; https://doi.org/10.3390/min12121591 - 12 Dec 2022
Cited by 2 | Viewed by 1251
Abstract
The southwestern South China Block is one of the most important Sn polymetallic ore districts in the world, of which the Dulong Sn-Zn polymetallic deposit, closely related to Late Cretaceous granitic magmatism, contains 0.4 Mt Sn, 5.0 Mt Zn, 0.2 Mt Pb, and [...] Read more.
The southwestern South China Block is one of the most important Sn polymetallic ore districts in the world, of which the Dulong Sn-Zn polymetallic deposit, closely related to Late Cretaceous granitic magmatism, contains 0.4 Mt Sn, 5.0 Mt Zn, 0.2 Mt Pb, and 7 Kt In, and is one of the largest Sn-Zn polymetallic deposits in this region. In this paper, on the basis of a 3D model of ore bodies established by the cut-off grade of the main ore-forming elements, the In grades were estimated by the ordinary Kriging method and the In-rich cells were extracted. The 3D models of strata, faults, granites, and granite porphyries in the mining area were established and assigned the attributes to the cells, which built buffer zones representing the influence space of the geological factors. The weight of evidence and artificial neural network methods were used to quantitatively evaluate the contribution of each geological factor to mineralization. The results show that the Neoproterozoic Xinzhai Formation (Pt3x), fault (F1), and Silurian granites (S3L) have considerable control effects on the occurrence of In-rich ore bodies. The metallogenic predictions according to the spatial coupling relationship of each geological factor in 3D space were carried out, and then the 3D-space-prospecting target areas of In-rich ore bodies were delineated. In addition, the early geological maps and data information of the mining area were comprehensively integrated in 3D space. The feasibility of 3D quantitative metallogenic prediction based on the deposit model was explored by comparing the two methods, and then, the 3D-space prospecting target area was delineated. The ROC curve evaluation shows that the results of two methods have indicative value for prospecting. The modeling results may support its use for future deep prospecting and exploitation of the Dulong and other similar deposits. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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33 pages, 11509 KiB  
Article
Fractal Structure Characteristics and Prospecting Direction of Dispersed Metals in the Eastern Guizhou Pb–Zn Metallogenic Belt, SW China
by Zhongliang Cui, Jiaxi Zhou, Kai Luo and Maoda Lu
Minerals 2022, 12(12), 1567; https://doi.org/10.3390/min12121567 - 05 Dec 2022
Viewed by 1103
Abstract
The eastern Guizhou Pb–Zn metallogenic belt (EGMB) is an important source of Pb–Zn resources and other critical minerals (including dispersed metals, such as Ge, Cd and Ga) in China. In order to ensure the continuous resource supply of Pb–Zn and associated dispersed metals, [...] Read more.
The eastern Guizhou Pb–Zn metallogenic belt (EGMB) is an important source of Pb–Zn resources and other critical minerals (including dispersed metals, such as Ge, Cd and Ga) in China. In order to ensure the continuous resource supply of Pb–Zn and associated dispersed metals, it is urgent to explore the direction of further prospecting for them. Fractal theory can realize the fractal structure characterization of fault structures and the spatial distribution of mineral deposits, which is helpful for mineral exploration. However, the fault fractal research and prospecting application are still seldom covered in the EGMB. We used fractal theory to determine fine-scale fractal structure characteristics of fault structures and ore deposits in the EGMB, and Fry analysis to delineate favorable metallogenic areas. The results show that within a scale range of 3.670–58.716 km, the integrated faults capacity dimension (CPD) is 1.5095, the information dimension (IND) is 1.5391, and the correlation dimension (CRD) is 1.5436, indicating fault structures with high maturity, which are conducive to the migration and accumulation of ore-forming fluids. The multi-fractal spectrum width and height are 0.3203 and 1.5355, respectively, implying a significant metallogenic potential. The spatial distribution fractal dimensions (SDD) of Pb–Zn specifically and metal deposits in general are 1.0193 and 1.0709, respectively; the quantity distribution fractal dimensions (QDD) are 1.4225 and 1.4716, respectively, and the density distribution fractal dimensions (DDD) are 1.422 and 1.472, respectively, indicating strong clustering. Hence, the favorable metallogenic regions can be divided into four grades, among which grade I region is continuously distributed in space and has the greatest prospecting potential. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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16 pages, 1962 KiB  
Article
Application of Machine Learning Algorithms to Classification of Pb–Zn Deposit Types Using LA–ICP–MS Data of Sphalerite
by Guo-Tao Sun and Jia-Xi Zhou
Minerals 2022, 12(10), 1293; https://doi.org/10.3390/min12101293 - 14 Oct 2022
Cited by 8 | Viewed by 1863
Abstract
Pb–Zn deposits supply a significant proportion of critical metals, such as In, Ga, Ge, and Co. Due to the growing demand for critical metals, it is urgent to clarify the different types of Pb–Zn deposits to improve exploration. The trace element concentrations of [...] Read more.
Pb–Zn deposits supply a significant proportion of critical metals, such as In, Ga, Ge, and Co. Due to the growing demand for critical metals, it is urgent to clarify the different types of Pb–Zn deposits to improve exploration. The trace element concentrations of sphalerite can be used to classify the types of Pb–Zn deposits. However, it is difficult to assess the multivariable system through simple data analysis directly. Here, we collected more than 2200 analyses with 14 elements (Mn, Fe, Co, Ni, Cu, Ga, Ge, Ag, Cd, In, Sn, Sb, Pb, and Bi) from 65 deposits, including 48 analyses from carbonate replacement (CR), 684 analyses from distal magmatic-hydrothermal (DMH), 197 analyses from epithermal, 456 analyses from Mississippi Valley-type (MVT), 199 analyses from sedimentary exhalative (SEDEX), 377 analyses from skarn, and 322 analyses from volcanogenic massive sulfide (VMS) types of Pb–Zn deposits. The critical metals in different types of deposits are summarized. Machine learning algorithms, namely, decision tree (DT), K-nearest neighbors (KNN), naive Bayes (NB), random forest (RF), and support vector machine (SVM), are applied to process and explore the classification. Learning curves show that the DT and RF classifiers are the most suitable for classification. Testing of the DT and RF classifier yielded accuracies of 91.2% and 95.4%, respectively. In the DT classifier, the feature importances of trace elements suggest that Ni (0.22), Mn (0.17), Cd (0.13), Co (0.11), and Fe (0.09) are significant for classification. Furthermore, the visual DT graph shows that the Mn contents of sphalerite allow the division of the seven classes into three groups: (1) depleted in Mn, including MVT and CR types; (2) enriched in Mn, including epithermal, skarn, SEDEX, and VMS deposits; and (3) DMH deposits, which have variable Mn contents. Data mining also reveals that VMS and skarn deposits have distinct Co and Ni contents and that SEDEX and DMH deposits have different Ni and Ge contents. The optimal DT and RF classifiers are deployed at Streamlit cloud workspace. Researchers can select DT or RF classifier and input trace element data of sphalerite to classify the Pb–Zn deposit type. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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