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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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22 pages, 5306 KB  
Article
Geochemical Signatures and Element Interactions of Volcanic-Hosted Agates: Insights from Interpretable Machine Learning
by Peng Zhang, Xi Xi and Bo-Chao Wang
Minerals 2025, 15(9), 923; https://doi.org/10.3390/min15090923 - 29 Aug 2025
Viewed by 343
Abstract
To unravel the link between agate geochemistry, host volcanic rocks, and ore-forming processes, this study integrated elemental correlation analysis, interaction interpretation, and interpretable machine learning (LightGBM-SHAP framework with SMOTE and 5-fold cross-validation) using 203 in-situ element datasets from 16 global deposits. The framework [...] Read more.
To unravel the link between agate geochemistry, host volcanic rocks, and ore-forming processes, this study integrated elemental correlation analysis, interaction interpretation, and interpretable machine learning (LightGBM-SHAP framework with SMOTE and 5-fold cross-validation) using 203 in-situ element datasets from 16 global deposits. The framework achieved 99.01% test accuracy and 97.4% independent prediction accuracy in discriminating host volcanic rock types. Key findings reveal divergence between statistical elemental correlations and geological interactions. Synergies reflect co-migration/co-precipitation, while antagonisms stem from source competition or precipitation inhibition, unraveling processes like stepwise crystallization. Rhyolite-hosted agates form via a “crust-derived magmatic hydrothermal fluid—medium-low salinity complexation—multi-stage precipitation” model, driven by high-silica fluids enriching Sb/Zn. Andesite-hosted agates follow a “contaminated fluid—hydrothermal alteration—precipitation window differentiation” model, controlled by crustal contamination. Basalt-hosted agates form through a “low-temperature hydrothermal fluid—basic alteration—progressive mineral decomposition” model, with meteoric water regulating Na-Zn relationships. Zn acts as a cross-lithology indicator, tracing crust-derived fluid processes in rhyolites, feldspar alteration intensity in andesites, and alteration timing in basalts. This work advances volcanic-agate genetic studies via “correlation—interaction—mineralization model” coupling, with future directions focusing on large-scale micro-area elemental analysis. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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29 pages, 5957 KB  
Article
Multistage Fluid Evolution and P-T Path at Ity Gold Deposit and Dahapleu Prospect (Western Ivory Coast)
by Yacouba Coulibaly, Michel Cathelineau and Marie-Christine Boiron
Minerals 2025, 15(9), 918; https://doi.org/10.3390/min15090918 - 28 Aug 2025
Viewed by 538
Abstract
Gold mineralisation at Ity (Ivory Coast) is spatially associated with skarns formed at contacts between carbonate-rich Birimian volcano-sedimentary rocks and felsic intrusions, whereas at Dahapleu, a nearby skarn-free prospect, gold occurs in structurally controlled shear zones. Gold occurs as native gold in pyrite [...] Read more.
Gold mineralisation at Ity (Ivory Coast) is spatially associated with skarns formed at contacts between carbonate-rich Birimian volcano-sedimentary rocks and felsic intrusions, whereas at Dahapleu, a nearby skarn-free prospect, gold occurs in structurally controlled shear zones. Gold occurs as native gold in pyrite or as a Bi–Te–Au–Ag telluride assemblage. Fluid inclusion data indicate that Ity formed through a hybrid model: a mesothermal orogenic gold system dominated by CO2–CH4 fluids at >350 °C, superimposed on earlier skarn mineralisation characterised by saline fluids. At Dahapleu, no skarn fluids were identified, but volatile-rich inclusions with more variable signatures (CO2, CO2–CH4, CO2–N2) indicate metamorphic fluids circulating in convective, fault-related systems and recording distinct fluid–rock interactions. The Ity–Dahapleu mineralising system thus displays fluid inclusion characteristics typical of mesothermal orogenic gold systems, likely at higher temperatures than most West African Birimian deposits. Overall, the Ity system reflects a long-lived thermal anomaly driving fluid circulation and metal deposition, with successive favourable events: rapid exhumation of hot lithospheric crust, granite intrusion, and skarn formation, followed by shear deformation and hydrothermal activity. Full article
(This article belongs to the Special Issue Mineralogy, Geochemistry and Fluid Inclusion Study of Gold Deposits Endowed in Critical Metals)
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15 pages, 7780 KB  
Article
Geochronological Constraints on the Genesis of the Changshitougounao Gold Deposit, Qinling Orogen
by Xian-Fa Xue, Sheng-Xiang Lu, Shou-Xu Wang, Da-Hu Yuan, Zheng-Wang Zeng, Jin-Hong Qiu and Jie Wang
Minerals 2025, 15(9), 903; https://doi.org/10.3390/min15090903 - 26 Aug 2025
Viewed by 727
Abstract
The Western Qinling Orogenic Belt, China’s second-largest Au-metallogenic province, hosts numerous polymetallic deposits, with gold resources particularly concentrated in the northwestern Xiahe–Hezuo area. The Changshitougounao gold deposit, located south of the Xiahe Fault, comprises disseminated ores controlled by near E–W-trending faults and is [...] Read more.
The Western Qinling Orogenic Belt, China’s second-largest Au-metallogenic province, hosts numerous polymetallic deposits, with gold resources particularly concentrated in the northwestern Xiahe–Hezuo area. The Changshitougounao gold deposit, located south of the Xiahe Fault, comprises disseminated ores controlled by near E–W-trending faults and is primarily hosted in quartz diorite and the Lower Triassic Longwuhe Formation. Zircon LA–ICP–MS U–Pb dating of fresh quartz diorite yields an age of 241.8 ± 2.6 Ma. Two generations of monazite were identified: type I magmatic monazite and type II hydrothermal monazite. Type I monazite is intergrown with feldspar, quartz, and biotite, and in situ LA–ICP–MS U–Pb analysis gives an age of 239.2 ± 2.2 Ma. Type II monazite occurs as irregular granular aggregates associated with Au-bearing sulfides and hydrothermal sericite, with an in situ U–Pb age of 230 ± 3.5 Ma. Apatite, also coeval with Au-bearing sulfides and type II monazite, yields an LA–ICP–MS U–Pb age of 230.9 ± 2.5 Ma and 230.7 ± 3.0 Ma. Zircon and type I monazite thus constrain the emplacement of the ore-bearing quartz diorite to ca. 240 Ma, whereas hydrothermal type II monazite and apatite constrain the timing of mineralization to ca. 230 Ma. The ~10 Ma interval between magmatism and mineralization indicates that goldmineralization in the Changshitougounao deposit is decoupled from Early Triassic magmatic activity. Integrating previous studies of the West Qinling geodynamic evolution, we infer that the Changshitougounao deposit formed during collisional orogenesis, in response to the closure of the Paleo-Tethys Ocean. Consequently, the Changshitougounao gold deposit is best classified as an orogenic gold system. Pyrite–arsenopyrite and sericite alteration serve as effective exploration vectors, and the contact zone between quartz diorite veins and slate represents a favorable structural setting for ore prospecting. Full article
(This article belongs to the Special Issue Gold–Polymetallic Deposits in Convergent Margins)
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13 pages, 5817 KB  
Article
Dissolution of Diamond in Water–Chloride Fluids at Mantle P-T Conditions
by Alexander Khokhryakov, Alexey Kruk, Alexander Sokol and Denis Nechaev
Minerals 2025, 15(9), 897; https://doi.org/10.3390/min15090897 - 24 Aug 2025
Viewed by 535
Abstract
Syngenetic fluid inclusions in natural diamonds are indicators of the composition of fluids responsible for growth and crystallization conditions. The chloride concentration in saline fluid inclusions of natural diamonds reaches 50 wt%. We study the dissolution of diamonds in the H2O-KCl-NaCl [...] Read more.
Syngenetic fluid inclusions in natural diamonds are indicators of the composition of fluids responsible for growth and crystallization conditions. The chloride concentration in saline fluid inclusions of natural diamonds reaches 50 wt%. We study the dissolution of diamonds in the H2O-KCl-NaCl system at temperatures of 1200 °C and 1400 °C and a pressure of 5.5 GPa using a BARS high-pressure multi-anvil apparatus. Two scenarios of diamond dissolution were experimentally investigated: (i) metasomatism by saline brines at high oxygen fugacity of the magnetite–hematite buffer; (ii) interaction with reduced carbon-unsaturated water–chloride fluid at low fO2 imposed by the iron–wüstite buffer. It is found that the presence of alkaline chlorides in the aqueous fluid significantly accelerates diamond dissolution at high oxygen fugacity but inhibits the process under reduced conditions. The morphology of diamond dissolution features is controlled by the presence of water in the fluid over the entire range of the studied P-T-fO2 conditions. Experimental results indicate that the interaction with oxidizing highly saline fluids during metasomatic events could negatively affect diamond preservation in mantle rocks and eventually lead to the formation of uneconomic kimberlites. Under reducing conditions, water–chloride fluids favor diamond preservation. Full article
(This article belongs to the Special Issue Unveiling the Depths: Advances in Kimberlite Research as Windows into Earth’s Evolution and Resource Potential)
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33 pages, 8102 KB  
Article
Fluid Components in Cordierites from Granulite- and Amphibolite-Facies Rocks of the Aldan Shield and Yenisei Ridge, Russia: Evidence from Pyrolysis-Free GC-MS, Raman, and IR Spectroscopy
by Ksenia Zatolokina, Anatoly Tomilenko, Taras Bul’bak and Nikolay Popov
Minerals 2025, 15(9), 890; https://doi.org/10.3390/min15090890 - 22 Aug 2025
Viewed by 614
Abstract
This study provides the first comprehensive characterization of fluid components in cordierites from both moderate- to high-pressure granulite facies of the Aldan Shield (Sutam and Nimnyr blocks), and granulite–amphibolite facies of the Yenisei Ridge (Kan and Yenisei series of the Angara–Kan complex), Russia, [...] Read more.
This study provides the first comprehensive characterization of fluid components in cordierites from both moderate- to high-pressure granulite facies of the Aldan Shield (Sutam and Nimnyr blocks), and granulite–amphibolite facies of the Yenisei Ridge (Kan and Yenisei series of the Angara–Kan complex), Russia, using integrated infrared and Raman spectroscopy coupled with pyrolysis-free gas chromatography–mass spectrometry (GC-MS). Granulite-facies cordierites record CO2-dominated fluids (XCO2 = CO2/(H2O + CO2) = 0.74–0.99) with elevated values (XCO2 = 0.89–0.99) in high-pressure, high-temperature (high-P-T) samples from the Sutam block and Kan series compared to moderate-P-T samples from the Nimnyr block (XCO2 = 0.74–0.84). Amphibolite-facies cordierites (Yenisei series) show significantly lower CO2 contents (XCO2 = 0.51–0.57) and higher H2O concentrations relative to high-pressure granulites. Critically, we report the first identification in cordierites of at least 12 homologous series of organic compounds and nitrogenated, sulfonated, and halogenated compounds. These results provide new constraints on fluid behavior across metamorphic facies transitions. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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13 pages, 7481 KB  
Article
Influence of Hydration on Shale Reservoirs: A Case Study of Gulong Shale Oil
by Feifei Fang, Ke Xu, Yu Zhang, Yu Wang, Zhimin Xu, Sijie He, Hui Huang, Hailong Wang, Weixiang Jin and Yue Gong
Minerals 2025, 15(8), 878; https://doi.org/10.3390/min15080878 - 21 Aug 2025
Viewed by 499
Abstract
In the process of the exploration and development of shale oil, the influence of hydration on shale reservoirs is complex, as it can not only improve porosity and permeability, but also lead to reservoir instability. At present, there is a lack of systematic [...] Read more.
In the process of the exploration and development of shale oil, the influence of hydration on shale reservoirs is complex, as it can not only improve porosity and permeability, but also lead to reservoir instability. At present, there is a lack of systematic understanding of the influence of hydration on the physical and chemical properties of shale oil reservoirs. Therefore, in this study, taking the Gulong shale oil reservoir in Songliao Basin as the research object, X-ray diffraction mineral composition analysis, electron microscope scanning, and micro-CT scanning were used to study the micro–macro-changes in shale caused by hydration, and the effects of different fracturing fluids on hydration were evaluated. The results show the following: (1) Hydration increases the porosity and permeability of Gulong shale through clay dispersion and dissolution pore formation, though these transient effects may compromise long-term reservoir stability due to pore-throat clogging. (2) Prolonged hydration significantly enhanced pore structure complexity, with tortuosity increasing by 64.7% (from 2.19 to 3.60) and the fractal dimension rising by 7.5% (from 1.99 to 2.14) with hydration time, and the proportion of larger pores (50–100 μm) increased significantly. (3) Hydration leads to crack propagation and new cracks, and the intersection of cracks reduces the core strength, which may eventually lead to macroscopic damage. (4) The influence of different fracturing fluids on the hydration reaction is obviously different. The higher the concentration, the stronger the hydration effect. Distilled water helps to increase porosity and permeability, but long-term effects may affect reservoir stability. The results of this paper reveal the changes in micro- and macro-characteristics of shale oil reservoirs under hydration, which is of great significance for analyzing the mechanism of hydration and provides theoretical support for improving shale oil recovery. Full article
(This article belongs to the Special Issue Clay Minerals: Roles in Oil and Gas Generation, Drilling, and Enhanced Recovery)
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33 pages, 7573 KB  
Article
A Stochastic Framework for Mineral Resource Uncertainty Quantification and Management at Compañía Minera Doña Inés de Collahuasi
by Alejandro Cáceres, Xavier Emery, Felipe Ibarra, Jorge Pérez, Sebastián Seguel, Gonzalo Fuster, Andrés Pérez and Rodrigo Riquelme
Minerals 2025, 15(8), 855; https://doi.org/10.3390/min15080855 - 13 Aug 2025
Viewed by 19228
Abstract
Mineral resource classification plays a critical role in communicating confidence levels, yet supporting methodologies such as drill-hole spacing analysis and geostatistical simulations are not consistently applied in routine updates of deterministic resource models. As a result, both local and global uncertainty quantification remain [...] Read more.
Mineral resource classification plays a critical role in communicating confidence levels, yet supporting methodologies such as drill-hole spacing analysis and geostatistical simulations are not consistently applied in routine updates of deterministic resource models. As a result, both local and global uncertainty quantification remain underutilized, and drilling requirements are often defined without a clear link to uncertainty reduction. This paper introduces a mineral resource uncertainty and drilling policy framework developed and applied at Compañía Minera Doña Inés de Collahuasi (CMDIC). The framework quantifies the uncertainty of each mineral resource model update when new data are available and provides an initial approach to determining drilling requirements based on CMDIC’s risk acceptance policies for different project stages. The proposed approach is a stochastic workflow that uses the current deterministic mineral resource model and database to generate geostatistical simulations. These simulations account for data quality, quantity, geological variability, and copper-grade variability. They form the basis for mineral resource classification with an explicit uncertainty quantification and provide an optimized drilling campaign to achieve desired risk levels subject to budget constraints. Because stochastic modeling updates faster than deterministic modeling, it provides timely insights from new drilling campaigns and delivers valuable insights for subsequent deterministic geological and grade modeling updates. The implementation of this workflow demonstrates its feasibility as a standard step following deterministic modeling, leading to cost-effective mineral resource development and management by aligning technical practices with the organization’s strategic objectives and risk preferences. Full article
(This article belongs to the Section Mineral Exploration Methods and Applications)
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39 pages, 13361 KB  
Article
Mineralogical, Petrological, 3D Modeling Study and Geostatistical Mineral Resources Estimation of the Zone C Gold Prospect, Kofi (Mali)
by Jean-Jacques Royer and Niakalé Camara
Minerals 2025, 15(8), 843; https://doi.org/10.3390/min15080843 - 8 Aug 2025
Viewed by 1230
Abstract
A 3D model integrating mineralogical, petrological, and geostatistical resource estimation was developed for Zone C of the Kofi Birimian gold deposit in Western Mali. Petrographic analysis identified two forms of gold mineralization: (i) native gold or electrum inclusions within pyrite, and (ii) disseminated [...] Read more.
A 3D model integrating mineralogical, petrological, and geostatistical resource estimation was developed for Zone C of the Kofi Birimian gold deposit in Western Mali. Petrographic analysis identified two forms of gold mineralization: (i) native gold or electrum inclusions within pyrite, and (ii) disseminated native gold along pyrite fractures. Four types of hydrothermal alteration–epidotization, chloritization, carbonatization, and albitization were observed microscopically. Statistical analysis of geochemical data classified five lithologies: mafic dyke, felsic dyke, diabase, faulted breccia, and intermediate quartz diorite. Minerals identified petrographically were corroborated by multivariate correlations among elements (Cr, Fe, Ni, Al, Ti, Na, and Ca), as revealed by Principal Component Analysis (PCA). A 3D borehole-based model revealed spatial correlations between hydrothermal alteration zones and associated geochemical anomalies, notably tourmalinization (B) and albitization (Na), with the latter serving as a key indicator for new exploration targets. The spatial associations of anomalous Ag, B, Hg, As, and Na commonly linked to tourmalinization suggest favorable zones for gold and silver mineralization. Geostatistical analysis identified isotropic continuous mineralized structures for most elements, including gold. Spherical isotropic variograms with ranges from 35 to 75 m were fitted for in situ resource estimation (e.g., silver ≈ 40 m; gold ≈ 60 m). The resulting estimated resources (indicated + inferred), based on a 1.0 g/t Au cut-off, are 2.476 Mt at 3.5 g/t Au indicated (0.278 Moz or 8.67 t), and 1.254 Mt at 2.78 g/t Au inferred (0.112 Moz or 3.49 t). This study provides a framework for identifying new mineralized zones, and the multidisciplinary approach demonstrates the connections between mineralogy and the information embedded in geochemical datasets, which are revealed through appropriate tools and an understanding of the underlying processes. Full article
(This article belongs to the Special Issue Advancements in Mineral Resource Characterization Using Machine Learning)
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22 pages, 5351 KB  
Article
Hydrometallurgical Leaching of Copper and Cobalt from a Copper–Cobalt Ore by Aqueous Choline Chloride-Based Deep Eutectic Solvent Solutions
by Emmanuel Anuoluwapo Oke, Yorkabel Fedai and Johannes Hermanus Potgieter
Minerals 2025, 15(8), 815; https://doi.org/10.3390/min15080815 - 31 Jul 2025
Viewed by 675
Abstract
The sustainable recovery of valuable metals such as Cu and Co from ores is a pressing need considering environmental and economic challenges. Therefore, this study evaluates the effectiveness of deep eutectic solvents (DESs) as alternative leaching agents for Cu and Co extraction. Four [...] Read more.
The sustainable recovery of valuable metals such as Cu and Co from ores is a pressing need considering environmental and economic challenges. Therefore, this study evaluates the effectiveness of deep eutectic solvents (DESs) as alternative leaching agents for Cu and Co extraction. Four DESs were prepared using choline chloride (ChCl) as a hydrogen bond acceptor (HBA) and oxalic acid (OA), ethylene glycol (EG), urea (U) and thiourea (TU) as hydrogen bond donors (HBDs). Leaching experiments were conducted with DESs supplemented with 30 wt.% water at varying temperatures, various solid-to-liquid ratios, and time durations. The ChCl:OA DES demonstrated the highest leaching efficiencies among the DESs tested on pure CuO and CoO, achieving 89.2% for Cu and 92.4% for Co (60 °C, 400 rpm, 6 h, −75 + 53 µm particle size, and 1:10 solid-to-liquid ratio). In addition, the dissolution kinetics, analysed using the shrinking core model (SCM), showed that the leaching process was mainly controlled by surface chemical reactions. The activation energy values for Cu and Co leaching were 46.8 kJ mol−1 and 51.4 kJ mol−1, respectively, supporting a surface chemical control mechanism. The results highlight the potential of ChCl:OA as a sustainable alternative for metal recovery. Full article
(This article belongs to the Special Issue Innovations in Hydrometallurgy: Traditional and Emerging Approaches for Sustainable Metal Recovery)
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31 pages, 29045 KB  
Article
Earliest Cambrian Carbonate Platform Evolution, Environmental Change, and Organic Matter Accumulation in the Northwestern Yangtze Block, South China
by Jincheng Liu, Qingchun Jiang, Yan Zhang, Jingjiang Liu, Yifei Ai, Pengzhen Duan and Guangyou Zhu
Minerals 2025, 15(8), 812; https://doi.org/10.3390/min15080812 - 31 Jul 2025
Viewed by 383
Abstract
The earliest Cambrian (ca., 538.8–524.8 Ma) was an important period in geological history witnessing significant environmental change, during which organic-rich facies were developed in the Yangtze Platform, South China. However, the contemporaneous paleogeographic and stratigraphic framework within which the environmental change and organic [...] Read more.
The earliest Cambrian (ca., 538.8–524.8 Ma) was an important period in geological history witnessing significant environmental change, during which organic-rich facies were developed in the Yangtze Platform, South China. However, the contemporaneous paleogeographic and stratigraphic framework within which the environmental change and organic matter accumulation took place remains poorly understood. We investigate this based on facies, sequence stratigraphic, and geochemical analyses of the lowermost Cambrian Maidiping and Zhujiaqing formations in the northwestern Yangtze Block. The results show that the terminal Ediacaran rimmed platform changed into a foredeep carbonate ramp and backbulge basin after the onset of the earliest Cambrian transgression. Across the Ediacaran–Cambrian boundary, the shallow-marine redox condition rapidly transitioned from relative euxinia to an oxygen-rich state. During the late transgression to highstand normal regression, the foredeep carbonate ramp expanded to the cratonic interior, and nutrients brought by intensified continental weathering and upwelling promoted significant phytoplankton proliferation, an increase in oxygen level and primary productivity, and then organic matter enrichment. During the forced regression, the carbonate ramp gradually changed into a rimmed platform. The weakening continental weathering and expanding anoxic area during the forced to lowstand normal regression led to the significant organic carbon burial in the foredeep basin. Full article
(This article belongs to the Special Issue Organic Petrology and Geochemistry: Exploring the Organic-Rich Facies)
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26 pages, 8845 KB  
Article
Occurrence State and Genesis of Large Particle Marcasite in a Thick Coal Seam of the Zhundong Coalfield in Xinjiang
by Xue Wu, Ning Lü, Shuo Feng, Wenfeng Wang, Jijun Tian, Xin Li and Hayerhan Xadethan
Minerals 2025, 15(8), 816; https://doi.org/10.3390/min15080816 - 31 Jul 2025
Viewed by 411
Abstract
The Junggar Basin contains a large amount of coal resources and is an important coal production base in China. The coal seam in Zhundong coalfield has a large single-layer thickness and high content of inertinite, but large particle Fe-sulphide minerals are associated with [...] Read more.
The Junggar Basin contains a large amount of coal resources and is an important coal production base in China. The coal seam in Zhundong coalfield has a large single-layer thickness and high content of inertinite, but large particle Fe-sulphide minerals are associated with coal seams in some mining areas. A series of economic and environmental problems caused by the combustion of large-grained Fe-sulphide minerals in coal have seriously affected the economic, clean and efficient utilization of coal. In this paper, the ultra-thick coal seam of the Xishanyao formation in the Yihua open-pit mine of the Zhundong coalfield is taken as the research object. Through the analysis of coal quality, X-ray fluorescence spectrometer test of major elements in coal, inductively coupled plasma mass spectrometry test of trace elements, SEM-Raman identification of Fe-sulphide minerals in coal and LA-MC-ICP-MS test of sulfur isotope of marcasite, the coal quality characteristics, main and trace element characteristics, macro and micro occurrence characteristics of Fe-sulphide minerals and sulfur isotope characteristics of marcasite in the ultra-thick coal seam of the Xishanyao formation are tested. On this basis, the occurrence state and genesis of large particle Fe-sulphide minerals in the ultra-thick coal seam of the Xishanyao formation are clarified. The main results and understandings are as follows: (1) the occurrence state of Fe-sulphide minerals in extremely thick coal seams is clarified. The Fe-sulphide minerals in the extremely thick coal seam are mainly marcasite, and concentrated in the YH-2, YH-3, YH-8, YH-9, YH-14, YH-15 and YH-16 horizons. Macroscopically, Fe-sulphide minerals mainly occur in three forms: thin film Fe-sulphide minerals, nodular Fe-sulphide minerals, and disseminated Fe-sulphide minerals. Microscopically, they mainly occur in four forms: flake, block, spearhead, and crack filling. (2) The difference in sulfur isotope of marcasite was discussed, and the formation period of marcasite was preliminarily divided. The overall variation range of the δ34S value of marcasite is wide, and the extreme values are quite different. The polyflake marcasite was formed in the early stage of diagenesis and the δ34S value was negative, while the fissure filling marcasite was formed in the late stage of diagenesis and the δ34S value was positive. (3) The coal quality characteristics of the thick coal seam were analyzed. The organic components in the thick coal seam are mainly inertinite, and the inorganic components are mainly clay minerals and marcasite. (4) The difference between the element content in the thick coal seam of the Zhundong coalfield and the average element content of Chinese coal was compared. The major element oxides in the thick coal seam are mainly CaO and MgO, followed by SiO2, Al2O3, Fe2O3 and Na2O. Li, Ga, Ba, U and Th are enriched in trace elements. (5) The coal-accumulating environment characteristics of the extremely thick coal seam are revealed. The whole thick coal seam is formed in an acidic oxidation environment, and the horizon with Fe-sulphide minerals is in an acidic reduction environment. The acidic reduction environment is conducive to the formation of marcasite and is not conducive to the formation of pyrite. (6) There are many matrix vitrinite, inertinite content, clay content, and terrigenous debris in the extremely thick coal seam. The good supply of peat swamp, suitable reduction environment and pH value, as well as groundwater leaching and infiltration, together cause the occurrence of large-grained Fe-sulphide minerals in the extremely thick coal seam of the Xishanyao formation in the Zhundong coalfield. Full article
(This article belongs to the Special Issue Mineralogical and Geochemical Characteristics of Coal and Coal-Bearing Strata)
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20 pages, 6964 KB  
Article
Mineralogical Analysis of Factors Affecting the Grade of High-Gradient Magnetic Separation Concentrates and Experimental Study on TiO2 Enrichment Using ARC
by Yifei Liu, Zhenqiang Liu, Yuhua Wang, Yuxin Zhang and Dongfang Lu
Minerals 2025, 15(8), 799; https://doi.org/10.3390/min15080799 - 30 Jul 2025
Viewed by 404
Abstract
High-gradient magnetic separation is a key step in the pre-concentration of ilmenite before flotation, particularly in the gravity separation process. However, as the amount of weakly magnetic gangue minerals increases, the grade of the coarse concentrate from high-gradient magnetic separation decreases. This paper [...] Read more.
High-gradient magnetic separation is a key step in the pre-concentration of ilmenite before flotation, particularly in the gravity separation process. However, as the amount of weakly magnetic gangue minerals increases, the grade of the coarse concentrate from high-gradient magnetic separation decreases. This paper investigates the mineralogical factors affecting the enrichment efficiency of high-gradient magnetic separation. Additionally, a newly developed stirred fluidized bed device, an agitated reflux classifier (ARC), was successfully applied to remove weakly magnetic gangue minerals that are difficult to separate by high-gradient magnetic separation (HGMS). For low-grade ilmenite with a feed grade of 3.97%, a combined process of magnetic separation and gravity separation was employed, achieving a concentrate with a grade of 16.50% and a recovery rate of 54.11%. This concentrate meets the requirements for flotation feed. This study provides a new approach for the beneficiation of low-grade ilmenite. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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10 pages, 1262 KB  
Communication
Gold as Pollution Tracer in Holocene Sediments of the Doñana National Park, the Largest Biological Reserve in Europe
by Verónica Romero, Francisco Ruiz, María Luz González-Regalado, María Isabel Carretero, Manuel Pozo, Guadalupe Monge, Luis Miguel Cáceres, Joaquín Rodríguez Vidal, Manuel Abad, Tatiana Izquierdo, Antonio Toscano, Paula Gómez and Gabriel Gómez
Minerals 2025, 15(8), 801; https://doi.org/10.3390/min15080801 - 30 Jul 2025
Viewed by 482
Abstract
Estuaries are excellent containers for the prehistorical and historical pollution that develops in their river basins. This paper studies the Au contents obtained by inductively coupled plasma spectrometry of two cores extracted from the Doñana National Park (Guadalquivir Estuary, SW Spain). Concentrations of [...] Read more.
Estuaries are excellent containers for the prehistorical and historical pollution that develops in their river basins. This paper studies the Au contents obtained by inductively coupled plasma spectrometry of two cores extracted from the Doñana National Park (Guadalquivir Estuary, SW Spain). Concentrations of this precious metal have been associated with the different prehistoric and historical stages of exploitation of the Iberian Pyritic Belt. The three detected peaks correspond to the first mining operations in the area around the park, the first systematic Tartessian mining and strong exploitation during the Roman period. Consequently, Au is an appropriate marker of the contamination phases prior to its current extraordinary biological diversity. Full article
(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)
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31 pages, 10410 KB  
Article
Integrated Prospectivity Mapping for Copper Mineralization in the Koldar Massif, Kazakhstan
by Dinara Talgarbayeva, Andrey Vilayev, Elmira Serikbayeva, Elmira Orynbassarova, Hemayatullah Ahmadi, Zhanibek Saurykov, Nurmakhambet Sydyk, Aigerim Bermukhanova and Berik Iskakov
Minerals 2025, 15(8), 805; https://doi.org/10.3390/min15080805 - 30 Jul 2025
Viewed by 799
Abstract
This study developed a copper mineral prospectivity map for the Koldar massif, Kazakhstan, using an integrated approach combining geophysical and satellite methods. A strong spatialgenetic link was identified between faults and hydrothermal mineralization, with faults acting as key conduits for ore-bearing fluids. Lineament [...] Read more.
This study developed a copper mineral prospectivity map for the Koldar massif, Kazakhstan, using an integrated approach combining geophysical and satellite methods. A strong spatialgenetic link was identified between faults and hydrothermal mineralization, with faults acting as key conduits for ore-bearing fluids. Lineament analysis and density mapping confirmed the high permeability of the Koldar massif, indicating its structural prospectivity. Hyperspectral and multispectral data (ASTER, PRISMA, WorldView-3) were applied for detailed mapping of hydrothermal alteration (phyllic, propylitic, argillic zones), which are critical for discovering porphyry copper deposits. In particular, WorldView-3 imagery facilitated the identification of new prospective zones. The transformation of magnetic and gravity data successfully delineated geological features and structural boundaries, confirming the fractured nature of the massif, a key structural factor for mineralization. The resulting map of prospective zones, created by normalizing and integrating four evidential layers (lineament density, PRISMA-derived hydrothermal alteration, magnetic, and gravity anomalies), is thoroughly validated, successfully outlining the known Aktogay, Aidarly, and Kyzylkiya deposits. Furthermore, new, previously underestimated prospective areas were identified. This work fills a significant knowledge gap concerning the Koldar massif, which had not been extensively studied using satellite methods previously. The key advantage of this research lies in its comprehensive approach and the successful application of high-quality hyperspectral imagery for mapping new prospective zones, offering a cost-effective and efficient alternative to traditional ground-based investigations. Full article
(This article belongs to the Section Mineral Exploration Methods and Applications)
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25 pages, 15689 KB  
Article
Mineralogical and Chemical Properties and REE Content of Bauxites in the Seydişehir (Konya, Türkiye) Region
by Muazzez Çelik Karakaya and Necati Karakaya
Minerals 2025, 15(8), 798; https://doi.org/10.3390/min15080798 - 29 Jul 2025
Viewed by 686
Abstract
The most important bauxite deposits in Türkiye are located in the Seydişehir (Konya) and Akseki (Antalya) regions, situated along the western Taurus Mountain, with a total reserve of approximately 44 million tons. Some of the bauxite deposits have been exploited for alumina since [...] Read more.
The most important bauxite deposits in Türkiye are located in the Seydişehir (Konya) and Akseki (Antalya) regions, situated along the western Taurus Mountain, with a total reserve of approximately 44 million tons. Some of the bauxite deposits have been exploited for alumina since the 1970s. In this study, bauxite samples, collected from six different deposits were examined to determine their mineralogical and chemical composition, as well as their REE content, with the aim of identifying which bauxite types are enriched in REEs and assessing their economic potential. The samples included massive, oolitic, and brecciated bauxite types, which were analyzed using optical microscopy, X-ray diffraction (XRD), X-ray fluorescence (XRF) and inductive coupled plasma-mass spectrometry (ICP-MS), field emission scanning electron microscopy (FESEM-EDX), and electron probe micro-analysis (EPMA). Massive bauxites were found to be more homogeneous in both mineralogical and chemical composition, predominantly composed of diaspore, boehmite, and rare gibbsite. Hematite is the most abundant iron oxide mineral in all bauxites, while goethite, rutile, and anatase occur in smaller quantities. Quartz, feldspar, kaolinite, dolomite, and pyrite were specifically determined in brecciated bauxites. Average oxide contents were determined as 52.94% Al2O3, 18.21% Fe2O3, 7.04% TiO2, and 2.69% SiO2. Na2O, K2O, and MgO values are typically below 0.5%, while CaO averages 3.54%. The total REE content of the bauxites ranged from 161 to 4072 ppm, with an average of 723 ppm. Oolitic-massive bauxites exhibit the highest REE enrichment. Cerium (Ce) was the most abundant REE, ranging from 87 to 453 ppm (avg. 218 ppm), followed by lanthanum (La), which reached up to 2561 ppm in some of the massive bauxite samples. LREEs such as La, Ce, Pr, and Nd were notably enriched compared to HREEs. The lack of a positive correlation between REEs and major element oxides, as well as with their occurrences in distinct association with Al- and Fe-oxides-hydroxides based on FESEM-EDS and EPMA analyses, suggests that the REEs are present as discrete mineral phases. Furthermore, these findings indicate that the REEs are not incorporated into the crystal structures of other minerals through isomorphic substitution or adsorption. Full article
(This article belongs to the Special Issue Critical Metal Minerals, 2nd Edition)
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39 pages, 8119 KB  
Article
Magmatic Redox Evolution and Porphyry–Skarn Transition in Multiphase Cu-Mo-W-Au Systems of the Eocene Tavşanlı Belt, NW Türkiye
by Hüseyin Kocatürk, Mustafa Kumral, Hüseyin Sendir, Mustafa Kaya, Robert A. Creaser and Amr Abdelnasser
Minerals 2025, 15(8), 792; https://doi.org/10.3390/min15080792 - 28 Jul 2025
Viewed by 658
Abstract
This study explores the magmatic and hydrothermal evolution of porphyry–skarn–transitional Cu-Mo-W-Au systems within the Nilüfer Mineralization Complex (NMC), located in the westernmost segment of the Eocene Tavşanlı Metallogenic Belt, NW Türkiye. Through integration of field data, whole-rock geochemistry, Re–Os molybdenite dating, and amphibole–biotite [...] Read more.
This study explores the magmatic and hydrothermal evolution of porphyry–skarn–transitional Cu-Mo-W-Au systems within the Nilüfer Mineralization Complex (NMC), located in the westernmost segment of the Eocene Tavşanlı Metallogenic Belt, NW Türkiye. Through integration of field data, whole-rock geochemistry, Re–Os molybdenite dating, and amphibole–biotite mineral chemistry, the petrogenetic controls on mineralization across four spatially associated mineralized regions (Kirazgedik, Güneybudaklar, Kozbudaklar, and Delice) were examined. The earliest and thermally most distinct phase is represented by the Kirazgedik porphyry system, characterized by high temperature (~930 °C), oxidized quartz monzodioritic intrusions emplaced at ~2.7 kbar. Rising fO2 and volatile enrichment during magma ascent facilitated structurally focused Cu-Mo mineralization. At Güneybudaklar, Re–Os geochronology yields an age of ~49.9 Ma, linking Mo- and W-rich mineralization to a transitional porphyry–skarn environment developed under moderately oxidized (ΔFMQ + 1.8 to +0.5) and hydrous (up to 7 wt.% H2O) magmatic conditions. Kozbudaklar represents a more reduced, volatile-poor skarn system, leading to Mo-enriched scheelite mineralization typical of late-stage W-skarns. The Delice system, developed at the contact of felsic cupolas and carbonates, records the broadest range of redox and fluid compositions. Mixed oxidized–reduced fluid signatures and intense fluid–rock interaction reflect complex, multistage fluid evolution involving both magmatic and external inputs. Geochemical and mineralogical trends—from increasing silica and Rb to decreasing Sr and V—trace a systematic evolution from mantle-derived to felsic, volatile-rich magmas. Structurally, mineralization is controlled by oblique fault zones that localize magma emplacement and hydrothermal flow. These findings support a unified genetic model in which porphyry and skarn mineralization styles evolved continuously from multiphase magmatic systems during syn-to-post-subduction processes, offering implications for exploration models in the Western Tethyan domain. Full article
(This article belongs to the Special Issue New Discovery and Exploration Methods of Porphyry and Epithermal Mineral Deposits)
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24 pages, 7393 KB  
Article
Thermodynamic Modeling Constrains the Alteration and Mineralization Patterns of the Pulang Porphyry Cu-Au Deposits in Eastern Tibet
by Shaoying Zhang, Wenyan He, Huaqing Wang and Yiwu Xiao
Minerals 2025, 15(8), 780; https://doi.org/10.3390/min15080780 - 25 Jul 2025
Viewed by 511
Abstract
Thermodynamic simulations of fluid–rock interactions provide valuable insights into mineral deposit formation mechanisms. This study investigates the Pulang porphyry Cu-Au deposit in the Sanjiang Tethys Orogen, employing both Gibbs energy minimization (GEM) and the Law of mass action (LMA) method to understand alteration [...] Read more.
Thermodynamic simulations of fluid–rock interactions provide valuable insights into mineral deposit formation mechanisms. This study investigates the Pulang porphyry Cu-Au deposit in the Sanjiang Tethys Orogen, employing both Gibbs energy minimization (GEM) and the Law of mass action (LMA) method to understand alteration overprinting and metal precipitation. The modeling results suggest that the ore-forming fluid related to potassic alteration was initially oxidized (ΔFMQ = +3.54~+3.26) with a near-neutral pH (pH = 5.0~7.0). Continued fluid–rock interactions, combined with the input of reduced groundwater, resulted in a decrease in both pH (4.8~6.1) and redox potential (ΔFMQ~+1), leading to the precipitation of propylitic alteration minerals and pyrrhotite. As temperature further decreased, fluids associated with phyllic alteration showed a slight increase in pH (5.8~6.0) and redox potential (ΔFMQ = +2). The intense superposition of propylitic and phyllic alteration on the potassic alteration zone is attributed to the rapid temperature decline in the magmatic–hydrothermal system, triggering fluid collapse and reflux. Mo, mainly transported as HMoO4− and MoO4−2, precipitated in the high-temperature range; Cu, carried primarily by CuCl complexes (CuCl4−3, CuCl2−, CuCl), precipitated over intermediate to high temperatures; and Au, transported as Au-S complexes (Au(HS)2−, AuHS), precipitated from intermediate to low temperatures. This study demonstrates that fluid–rock interactions alone can account for the observed sequence of alteration and mineralization in porphyry systems. Full article
(This article belongs to the Special Issue Thermal History and Preservation Mechanisms of Porphyry-Cu Deposits: Evidence from Thermochronology, Mineral and Isotopic Geochemistry)
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32 pages, 32586 KB  
Article
Magmatic Evolution at the Saindak Cu-Au Deposit: Implications for the Formation of Giant Porphyry Deposits
by Jun Hong, Yasir Shaheen Khalil, Asad Ali Narejo, Xiaoyong Yang, Tahseenullah Khan, Zhihua Wang, Huan Tang, Haidi Zhang, Bo Yang and Wenyuan Li
Minerals 2025, 15(8), 768; https://doi.org/10.3390/min15080768 - 22 Jul 2025
Viewed by 1922
Abstract
The Chagai porphyry copper belt is a major component of the Tethyan metallogenic domain, which spans approximately 300 km and hosts several giant porphyry copper deposits. The tectonic setting, whether subduction-related or post-collisional, and the deep dynamic processes governing the formation of these [...] Read more.
The Chagai porphyry copper belt is a major component of the Tethyan metallogenic domain, which spans approximately 300 km and hosts several giant porphyry copper deposits. The tectonic setting, whether subduction-related or post-collisional, and the deep dynamic processes governing the formation of these giant deposits remain poorly understood. Mafic microgranular enclaves (MMEs), mafic dikes, and multiple porphyries have been documented in the Saindak mining area. This work examines both the ore-rich and non-ore intrusions in the Saindak porphyry Cu-Au deposit, using methods like molybdenite Re-Os dating, U-Pb zircon ages, Hf isotopes, and bulk-rock geochemical data. Geochronological results indicate that ore-fertile and barren porphyries yield ages of 22.15 ± 0.22 Ma and 22.21 ± 0.33 Ma, respectively. Both MMEs and mafic dikes have zircons with nearly identical 206Pb/238U weighted mean ages (21.21 ± 0.18 Ma and 21.21 ± 0.16 Ma, respectively), corresponding to the age of the host rock. Geochemical and Sr–Nd–Hf isotopic evidence indicates that the Saindak adakites were generated by the subduction of the Arabian oceanic lithosphere under the Eurasian plate, rather than through continental collision. The adakites were mainly formed by the partial melting of a metasomatized mantle wedge, induced by fluids from the dehydrating subducting slab, with minor input from subducted sediments and later crust–mantle interactions during magma ascent. We conclude that shallow subduction of the Arabian plate during the Oligocene–Miocene may have increased the flow of subducted fluids into the sub-arc mantle source of the Chagai arc. This process may have facilitated the widespread deposition of porphyry copper and copper–gold mineralization in the region. Full article
(This article belongs to the Section Mineral Deposits)
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20 pages, 1677 KB  
Review
Froth Flotation of Lepidolite—A Review
by Xusheng Yang, Bo Feng and Longxia Jiang
Minerals 2025, 15(7), 750; https://doi.org/10.3390/min15070750 - 17 Jul 2025
Cited by 1 | Viewed by 605
Abstract
As one of the important lithium resource sources, lepidolite has become a new energy strategic resource research hot spot. The efficient flotation of lepidolite directly affects the recovery and economic value of lithium resources. This paper systematically reviews the flotation research progress of [...] Read more.
As one of the important lithium resource sources, lepidolite has become a new energy strategic resource research hot spot. The efficient flotation of lepidolite directly affects the recovery and economic value of lithium resources. This paper systematically reviews the flotation research progress of lepidolite, focusing on the influence of the type of capture agent and process parameters (pH, activator, and depressant) on flotation. In view of the separation problems caused by the similarity of the surface properties of lepidolite and its associated gangue minerals (albite, feldspar, and quartz), the strategies for regulating the crystal structure of the minerals and their surface properties are analyzed. In addition, the lepidolite flotation process and its challenges are summarized, including poor selectivity of chemicals, fine mineral embedded size, easy to form sludge, and insufficient environmental friendliness, etc. The future development direction of lepidolite flotation technology is also prospected, which provides theoretical support and reference for the efficient recovery of lepidolite. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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21 pages, 8925 KB  
Article
Zr-Th-REE Mineralization Associated with Albite–Aegirine-Bearing Rocks of the Burpala Alkaline Intrusion (North Baikal Region, South Margin of the Siberian Craton)
by Ivan Aleksandrovich Izbrodin, Anna Gennadievna Doroshkevich, Anastasia Evgenyevna Starikova, Alexandra Vladislavovna Malyutina, Tatyana Nikolaevna Moroz and Igor Sergeevich Sharygin
Minerals 2025, 15(7), 742; https://doi.org/10.3390/min15070742 - 16 Jul 2025
Viewed by 402
Abstract
The rocks of the Burpala alkaline intrusion contain a wide range of rare minerals that concentrate rare earth elements (REEs), Nb, Th, Li, and other incompatible elements. One of the examples of the occurrence of such mineralization is albite–aegirine rocks located at the [...] Read more.
The rocks of the Burpala alkaline intrusion contain a wide range of rare minerals that concentrate rare earth elements (REEs), Nb, Th, Li, and other incompatible elements. One of the examples of the occurrence of such mineralization is albite–aegirine rocks located at the contact zone between the intrusion and the host terrigenous–sedimentary rock. In albite–aegirine rocks, cubic crystals of “metaloparite”, partially or completely substituted by bastnäsite-(Ce) and polymorphic TiO2 phases (anatase and rutile) mainly represent the rare metal minerals. In albite–aegirine rocks, trace element minerals are predominantly represented by cubic crystals of “metaloparite”, which are partially or completely replaced by bastnäsite-(Ce) and polymorphic TiO2 phases such as anatase and rutile. Additionally, Th-bearing zircon (up to 17.7 wt% ThO2) and a variety of unidentified minerals containing REEs, Th, and Nb were detected. The obtained data indicate that bastnäsite-(Ce) is the result of the recrystallization of “metaloparite” accompanied by the formation of Th-bearing zircon and Nb-bearing rutile (up to 9.9 wt% Nb2O5) and the separation of various undiagnosed, unidentified LREE phases. Our studies show that remobilization of LREEs, HFSEs, and local enrichment of rocks in these elements occurred due to the effects of residual fluid enriched in fluorine and carbon dioxide. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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23 pages, 1663 KB  
Review
Adsorption of Antibiotics by Natural Clay Minerals
by Leonid Perelomov, Maria Gertsen, Saglara Mandzhieva, Vadim Sychev, Tamara Dudnikova, Ilya Khaidanov, Irina Perelomova, Tatiana Minkina and Yurii Atroshchenko
Minerals 2025, 15(7), 733; https://doi.org/10.3390/min15070733 - 14 Jul 2025
Viewed by 1043
Abstract
The use of widespread and inexpensive clay minerals as adsorptive agents, as well as materials obtained by their chemical modification, can contribute to the solution of the problem of environmental pollution with antibiotics. This review considers the structural features of various natural clay [...] Read more.
The use of widespread and inexpensive clay minerals as adsorptive agents, as well as materials obtained by their chemical modification, can contribute to the solution of the problem of environmental pollution with antibiotics. This review considers the structural features of various natural clay minerals and the effect of these features on their sorption capacity. Based on the analysis of available papers (over the last 15 years, also including some fundamental basics over the last 20–30 years), it has been established that the main property of an antibiotic molecule affecting the ability to be adsorbed by a clay mineral is the hydrophilicity of the organic substance molecule. The leading properties that determine the ability of clays to adsorb antibiotics are the charge and area of their surfaces. The ability of antibiotic molecules to protonate and a partial change in the edge charge of mineral layers is determined by the acidity of the sorption solution. In addition, empirical evidence is provided that the most important factors affecting adsorption are the ionic strength of the sorption solution, the concentration of the adsorbent and adsorbate, and the interaction temperature. The diversity of the composition, structure, and properties of clay minerals allows them to be effective sorbents for a wide range of antibiotics. Full article
(This article belongs to the Section Clays and Engineered Mineral Materials)
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26 pages, 2032 KB  
Review
A Cross-Disciplinary Review of Rare Earth Elements: Deposit Types, Mineralogy, Machine Learning, Environmental Impact, and Recycling
by Mustafa Rezaei, Gabriela Sanchez-Lecuona and Omid Abdolazimi
Minerals 2025, 15(7), 720; https://doi.org/10.3390/min15070720 - 9 Jul 2025
Viewed by 2412
Abstract
Rare-earth elements (REEs), including lanthanides, scandium, and yttrium, are important for advanced technologies such as renewable energy systems, electronics, medical diagnostics, and precision agriculture. Despite their relative crustal abundance, REE extraction is impeded by complex geochemical behavior, dispersed distribution, and environmental challenges. This [...] Read more.
Rare-earth elements (REEs), including lanthanides, scandium, and yttrium, are important for advanced technologies such as renewable energy systems, electronics, medical diagnostics, and precision agriculture. Despite their relative crustal abundance, REE extraction is impeded by complex geochemical behavior, dispersed distribution, and environmental challenges. This review presents a comprehensive overview of REE geochemistry, mineralogy, and major deposit types including carbonatites, alkaline igneous rocks, laterites, placer deposits, coal byproducts, and marine sediments. It also highlights the global distribution and economic potential of key REE projects. The integration of machine learning has further enhanced exploration by enabling deposit classification and geochemical modeling, especially in data-limited regions. Environmental and health challenges associated with REE mining, processing, and electronic waste (e-waste) recycling are studied, along with the expanding use of REEs in agriculture and medicine. Some recycling efforts offer promise for supply diversification, but significant technological and economic barriers remain. Ensuring a secure and sustainable REE supply will require integrated approaches combining advanced analytics, machine learning, responsible extraction, and coordinated policy efforts. The present review offers a general overview that can be useful for informing future studies and resource-related discussions. Full article
(This article belongs to the Special Issue Editorial Board Members’ Collection Series: "Critical and Strategic Minerals", 2nd Edition)
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21 pages, 12768 KB  
Article
Applicability Analysis with the Improved Spectral Unmixing Models Based on the Measured Hyperspectral Data of Mixed Minerals
by Haonan Zhang, Lizeng Duan, Yang Zhang, Huayu Li, Donglin Li and Yan Li
Minerals 2025, 15(7), 715; https://doi.org/10.3390/min15070715 - 6 Jul 2025
Cited by 1 | Viewed by 674
Abstract
Hyperspectral technology can non-destructively identify and analyze minerals. However, the quantitative inversion of different components in mixed minerals remains difficult in mineral spectral analysis. A set of mineral samples was prepared from dolomite and gypsum, varying in their components. Three improved spectral decomposition [...] Read more.
Hyperspectral technology can non-destructively identify and analyze minerals. However, the quantitative inversion of different components in mixed minerals remains difficult in mineral spectral analysis. A set of mineral samples was prepared from dolomite and gypsum, varying in their components. Three improved spectral decomposition models were proposed: the Continuum Removal-Fully Constrained Linear Spectral Model (CR-FCLSM), the Natural Logarithm-Fully Constrained Linear Spectral Model (NL-FCLSM), and the Ratio Derivative Model (RDM). The unmixing Abundance Error (AE) was 0.161, 0.051, and 0.082 for CR-FCLSM, NL-FCLSM, and RDM. The results of the three improved linearized unmixing models are better than those of the traditional linear spectral unmixing model. The NL-FCLSM effectively enhanced the linear characteristics of the spectrum, making it more suitable for two mineral mixing scenarios. The systematic bias of CR-FCLSM may be due to its insufficient sensitivity to low-abundance signals. The stability of RDM depends on the selection of a strong linear band. The unmixing experiments of the measured spectra and the data from the USGS spectral library demonstrate that the improved linear unmixing model is more accurate than the traditional linear spectral model and simpler to calculate than the nonlinear spectral model, providing a new approach for demodulating hyperspectral images. Full article
(This article belongs to the Section Mineral Exploration Methods and Applications)
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32 pages, 68153 KB  
Review
Barite Deposits of Türkiye: A Review
by Zeynep Cansu, Hüseyin Öztürk and Nurullah Hanilçi
Minerals 2025, 15(7), 692; https://doi.org/10.3390/min15070692 - 28 Jun 2025
Viewed by 703
Abstract
Türkiye hosts a wide variety of barite deposits that can be broadly classified into two major groups based on their tectonic settings: magmatism-associated and passive margin-hosted deposits. The magmatism-associated deposits include Kızılcaören (F + Ba + REE + Th, Beylikova–Eskişehir), Kirazören (Bulancak–Giresun), and [...] Read more.
Türkiye hosts a wide variety of barite deposits that can be broadly classified into two major groups based on their tectonic settings: magmatism-associated and passive margin-hosted deposits. The magmatism-associated deposits include Kızılcaören (F + Ba + REE + Th, Beylikova–Eskişehir), Kirazören (Bulancak–Giresun), and Karacaören (Mesudiye–Ordu). The Kızılcaören deposit formed in relation to the emplacement of a late Oligocene carbonatitic sill, while the Kirazören and Karacaören deposits are associated with the Cretaceous Pontide magmatic arc. Passive margin-hosted deposits occur within various Paleozoic sedimentary lithologies—such as metasandstone, shale, schist, and limestone—and are found in the Taurides and the Arabian Platform. These deposits occur as either concordant or discordant veins. This barite belt extends from Şarkikaraağaç (Isparta), through Hüyük (Konya) and Alanya (Antalya), to Silifke (Mersin), Tordere (Adana), Önsen, Şekeroba (Kahramanmaraş), and Hasköy (Muş). The Paleozoic deposits represent the major barite resources of Türkiye, with an annual production of approximately 300,000 metric tons. Smaller deposits around Gazipaşa (Antalya) contain minor Pb-Zn sulfides. Mesozoic barite deposits are hosted in Triassic dolomites and are associated with Pb-Zn mineralization in the Hakkari region of the Arabian Platform. Pb and Sr isotope data indicate that the barium in these deposits was derived from ancient continental crust. The isotopic compositions of both concordant (stratabound) and discordant (vein-type) barites are generally homogeneous. In northwestern Türkiye, the Sr isotope compositions of the barite deposits align well with those of the Oligocene carbonatite host complex. The 87Sr/86Sr isotope ratio of the Kızılcaören deposit (0.706‰) is the least radiogenic among Turkish barite deposits, suggesting a mantle contribution. The Kirazören deposit in the Pontide magmatic arc follows with a slightly higher ratio (0.707‰). Triassic barites from the Hakkari region yield 87Sr/86Sr values around 0.709‰, slightly more radiogenic than coeval seawater. Paleozoic barite deposits show the most radiogenic 87Sr/86Sr values, including Aydıncık (0.718‰), Şarkikaraağaç (0.714‰), Hasköy (0.713‰), Kahramanmaraş (0.712‰), Tordere, and Hüyük (both 0.711‰), consistent with their respective host rocks. The elevated radiogenic Pb and Sr isotope values in the passive margin-hosted deposits suggest that the barium originated from deeper, barium-enriched rocks, whereas stable sulfur isotope data point to a marine sulfur source. Moreover, Sr and S isotopic signatures indicate that the Paleozoic sediment-hosted deposits formed in association with cold seeps on the seafloor, resembling modern analogs. In contrast, the Mesozoic Karakaya deposit (Hakkari) represents a typical vent-proximal, sediment-hosted deposit with no magmatic signature. Full article
(This article belongs to the Special Issue Stratabound Barite Deposits: Mineralogy, Isotope Geochemistry and Geochronology)
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32 pages, 21563 KB  
Article
Diagenetic Classification—A New Concept in the Characterization of Heterogeneous Carbonate Reservoirs: Permian–Triassic Successions in the Persian Gulf
by Hamzeh Mehrabi, Saghar Sadat Ghoreyshi, Yasaman Hezarkhani and Kulthum Rostami
Minerals 2025, 15(7), 690; https://doi.org/10.3390/min15070690 - 27 Jun 2025
Viewed by 529
Abstract
Understanding diagenetic processes is fundamental to characterizing heterogeneous carbonate reservoirs, where variations in pore structures and mineralogy significantly influence reservoir quality and fluid flow behavior. This study presents an integrated diagenetic classification approach applied to the upper Dalan and Kangan formations in the [...] Read more.
Understanding diagenetic processes is fundamental to characterizing heterogeneous carbonate reservoirs, where variations in pore structures and mineralogy significantly influence reservoir quality and fluid flow behavior. This study presents an integrated diagenetic classification approach applied to the upper Dalan and Kangan formations in the Persian Gulf. Utilizing extensive core analyses, petrographic studies, scanning electron microscopy (SEM) imaging, and petrophysical data, six distinct diagenetic classes were identified based on the quantification of key processes such as dolomitization, dissolution, cementation, and compaction. The results reveal that dolomitization and dissolution enhance porosity and permeability, particularly in high-energy shoal facies, while cementation and compaction tend to reduce reservoir quality. A detailed petrographic examination and rock typing, including pore type classification and hydraulic flow unit analysis using flow zone indicator methods, allowed the subdivision of the reservoir into hydraulically meaningful units with consistent petrophysical characteristics. The application of the Stratigraphic Modified Lorenz Plot facilitated large-scale reservoir zonation, revealing the complex internal architecture and significant heterogeneity controlled by depositional environments and diagenetic overprints. This diagenetic classification framework improves predictive modeling of reservoir behavior and fluid distribution, supporting the optimization of exploitation strategies in heterogeneous carbonate systems. The approach demonstrated here offers a robust template for similar carbonate reservoirs worldwide, emphasizing the importance of integrating diagenetic quantification with multi-scale petrophysical and geological data to enhance reservoir characterization and management. Full article
(This article belongs to the Special Issue Carbonate Petrology and Geochemistry, 2nd Edition)
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25 pages, 3819 KB  
Article
Evolution of Mafic Tungnárhraun Lavas: Transcrustal Magma Storage and Ascent Beneath the Bárðarbunga Volcanic System
by Tanya Furman, Denali Kincaid and Collin Oborn Brady
Minerals 2025, 15(7), 687; https://doi.org/10.3390/min15070687 - 27 Jun 2025
Viewed by 629
Abstract
The Tungnárhraun basalts in southern Iceland record a transcrustal magma system formed during Holocene deglaciation. These large-volume (>1 km3) Early through Mid-Holocene lavas contain ubiquitous plagioclase feldspar macrocrysts that are too primitive to have grown from the host lavas. Thermobarometry based [...] Read more.
The Tungnárhraun basalts in southern Iceland record a transcrustal magma system formed during Holocene deglaciation. These large-volume (>1 km3) Early through Mid-Holocene lavas contain ubiquitous plagioclase feldspar macrocrysts that are too primitive to have grown from the host lavas. Thermobarometry based on plagioclase melt and clinopyroxene melt equilibrium reveals a transcrustal structure with at least three distinct storage regions. A lower-crustal mush zone at ~14–30 km is fed by primitive, low 87Sr/86Sr magmas with diverse Ti/K and Al/Ti signatures. Plagioclase feldspar growth is controlled by an experimentally determined pseudoazeotrope where crystals develop inversely correlated An and Mg contents. The rapid ascent of magmas to mid-crustal levels (~8–9 km) allows the feldspar system to revert to conventional thermodynamic phase constraints. Continued plagioclase growth releases heat, causing olivine and pyroxene to be resorbed and giving the magmas their characteristic high CaO/Al2O3 values (~0.8–1.0) and Sc contents (~52 ppm in matrix material). Mid-Holocene MgO-rich lavas with abundant plagioclase feldspar macrocrysts erupted directly from this depth, but both older and younger magmas ascended to a shallow-crustal storage chamber (~5 km) where they crystallized olivine, clinopyroxene, and plagioclase feldspar and evolved to lower MgO contents. The Sr isotope differences between the plagioclase macrocrysts and their carrier melts suggest that the fractionation involves the minor assimilation of country rock. This model does not require the physical disruption of an established and long-lived gabbroic cumulate mush. The transcrustal structures documented here existed in south Iceland at least throughout the Holocene and likely influenced much of Icelandic magmatism. Full article
(This article belongs to the Special Issue Trans-Crustal Evolution of Magmas: Clues from Thermodynamic and Geochemical Modelling, Thermo-Barometry and Experimental Petrology)
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31 pages, 34129 KB  
Article
Prediction of Buried Cobalt-Bearing Arsenides Using Ionic Leach Geochemistry in the Bou Azzer-El Graara Inlier (Central Anti-Atlas, Morocco): Implications for Mineral Exploration
by Yassine Lmahfoudi, Houssa Ouali, Said Ilmen, Zaineb Hajjar, Ali El-Masoudy, Russell Birrell, Laurent Sapor, Mohamed Zouhair and Lhou Maacha
Minerals 2025, 15(7), 676; https://doi.org/10.3390/min15070676 - 24 Jun 2025
Viewed by 1080
Abstract
The Aghbar-Bou Azzer East mining district (ABED) is located between the Bou Azzer East and Aghbar deposits. It is an area of approximately 7 km long towards ENE–WSW and 2 km wide towards N–S. In this barren area, volcano-sedimentary rocks are attributed to [...] Read more.
The Aghbar-Bou Azzer East mining district (ABED) is located between the Bou Azzer East and Aghbar deposits. It is an area of approximately 7 km long towards ENE–WSW and 2 km wide towards N–S. In this barren area, volcano-sedimentary rocks are attributed to the Ouarzazate group outcrop (Ediacarian age): they are composed of volcanic rocks (ignimbrite, andesite, rhyolite, dacite, etc.) covered by the Adoudou detritic formation in angular unconformity. Given the absence of serpentinite outcrops, exploration investigation in this area has been very limited. This paper aims to use ionic leach geochemistry (on samples of soil) to detect the presence of Co-bearing arsenides above hidden ore deposits in this unexplored area of the Bou Azzer inlier. In addition, a detailed structural analysis allowed the identification of four families of faults and fractures with or without filling. Three directional major fault systems of several kilometers in length and variable orientation in both the Cryogenian basement and the Ediacaran cover have been identified: (i) ENE–WSW, (ii) NE–SW, and (iii) NW–SE. Several geochemical anomalies for Co, As, Ni, Ag, and Cu are aligned along three main directions, including NE–SW, NW–SE, and ENE–WSW. They are particularly well-defined in the western zone but are only minor in the central and eastern zones. Some of these anomalies correlate with the primary structural features observed in the studied area. These trends are consistent with those known under mining exploitation in nearby ore deposits, supporting the potential for similar mineralization in the ABED. Based on structural analysis and ionic leach geochemistry, drilling programs were conducted in the study area, confirming the continuity of serpentinites at depth beneath the Ediacaran cover and the presence of Co–Fe-bearing arsenide ores. This validates the ionic geochemistry technique as a reliable method for exploring buried ore deposits. Full article
(This article belongs to the Special Issue Novel Methods and Applications for Mineral Exploration, Volume III)
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24 pages, 4791 KB  
Article
Zircon out, Elpidite in: Deformation-Driven Zirconosilicate Evolution in Peralkaline Granites: A Case Study of the Papanduva Pluton (Brazil)
by Larissa P. Grangeiro, Frederico C. J. Vilalva, Silvio R. F. Vlach and Armando L. S. de Oliveira
Minerals 2025, 15(7), 667; https://doi.org/10.3390/min15070667 - 20 Jun 2025
Viewed by 354
Abstract
The peralkaline granites of the Papanduva Pluton (South Brazil) display a remarkable facies dichotomy, with zircon dominant in massive facies and diverse zirconosilicates (Zr-Si) in foliated facies. This study employs petrography and mineral chemistry (major and trace elements) to elucidate the textural diversity [...] Read more.
The peralkaline granites of the Papanduva Pluton (South Brazil) display a remarkable facies dichotomy, with zircon dominant in massive facies and diverse zirconosilicates (Zr-Si) in foliated facies. This study employs petrography and mineral chemistry (major and trace elements) to elucidate the textural diversity and compositional evolution of these minerals. Three discrete zirconosilicate groups were identified: Na-rich elpidite (euhedral, vein-like, and granular varieties), Na-poor (Na,K)Zr-Si-I, and silica-rich (Na,K)Zr-Si-II. Contrary to the expected crystallization sequences, trace element data reveal that REE enrichment correlates with deformation intensity rather than paragenetic order, with vein-like aggregates along deformation features showing the highest REE concentrations. Statistical analysis demonstrates significant correlations between REE contents and alkali exchange patterns. We propose a three-stage evolutionary model involving magmatic crystallization, deformation-enhanced fluid interaction, and late-stage recrystallization, with a progressive evolution from Na-dominated to K-dominated conditions. This study provides new insights into closed-system fluid evolution in agpaitic environments and highlights deformation as a primary control on element mobility in peralkaline granitic systems. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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34 pages, 12770 KB  
Article
Immiscibility in Magma Conduits: Evidence from Granitic Enclaves
by Ya Tian, Guanglai Li, Yongle Yang, Chao Huang, Yinqiu Hu, Kai Xu and Ji Zhang
Minerals 2025, 15(7), 664; https://doi.org/10.3390/min15070664 - 20 Jun 2025
Viewed by 385
Abstract
Many granitic enclaves are developed in the volcanic channel of the Xiangshan volcanic basin. To explore their genesis, this study examined the petrography, geochemistry, LA-ICP-MS zircon U–Pb chronology, and zircon Hf isotopes of the granitic enclaves and compared them with the porphyroclastic lavas. [...] Read more.
Many granitic enclaves are developed in the volcanic channel of the Xiangshan volcanic basin. To explore their genesis, this study examined the petrography, geochemistry, LA-ICP-MS zircon U–Pb chronology, and zircon Hf isotopes of the granitic enclaves and compared them with the porphyroclastic lavas. In general, the granitic enclaves and porphyroclastic lavas have similar structures, and the rock-forming minerals and accessory minerals have relatively close compositions. In terms of rock geochemical characteristics, the granitic enclaves are richer in silicon and alkalis but have lower abundances of aluminum, magnesium, iron, and calcium than the porphyroclastic lavas. Rb, Th, K, Sm, and other elements are more enriched, whereas Ba, Ti, Nb, P, and other elements are more depleted. The granitic enclaves have lower rare earth contents (195.53 × 10−6–271.06 × 10−6) than the porphyroclastic lavas (246.67 × 10−6–314.27 × 10−6). The rare earth element distribution curves of the two are generally consistent, both right-leaning, and enriched with light rare earth patterns. The weighted average zircon U–Pb ages of two granitic enclave samples were 135.45 ± 0.54 Ma (MSWD = 0.62, n = 17) and 135.81 ± 0.60 Ma (MSWD = 0.40, n = 20), respectively, which are consistent with the weighted average age of a single porphyroclastic lava sample of 134.01 ± 0.53 Ma (MSWD = 2.0, n = 20). The zircons of the two kinds of rocks crystallize at almost the same temperature. The consistent trend of the rare earth element distribution curve of zircons in the granitic enclaves and the porphyroclastic lava samples indicates that the zircons of the two samples were formed in the same stage. The formation process of granitic enclaves may be that the lower crustal melt is induced to rise, and the crystallization differentiation occurs in the magma reservoir and is stored in the form of crystal mush, forming a shallow crystal mush reservoir. The crystal mush reservoir is composed of a large number of rock-forming minerals such as quartz, feldspar, and biotite, as well as accessory mineral crystals such as zircon and flowable intergranular melt. In the later stage of magma high evolution, a small and short-time magmatic activity caused a large amount of crystalline granitic crystal mush to pour into the volcanic pipeline. In the closed system of volcanic pipeline, the pressure and temperature decreased rapidly, and the supercooling degree increased, and the immiscibility finally formed pale granitic enclaves. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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18 pages, 6291 KB  
Article
Petrological Exploration of Magma Storage and Evolution Conditions at the Eastern Virunga Volcanic Province (Rwanda, East African Rift System)
by Fabio Colle, Teresa Trua, Serena Giacomelli, Massimo D’Orazio and Roberto Valentino
Minerals 2025, 15(7), 666; https://doi.org/10.3390/min15070666 - 20 Jun 2025
Cited by 1 | Viewed by 447
Abstract
The Virunga Volcanic Province (VVP), located in the western branch of the East African Rift System, hosts a variety of alkaline lavas erupted from closely spaced volcanic centers. However, the magmatic system of this region, particularly in its eastern sector, remains insufficiently constrained. [...] Read more.
The Virunga Volcanic Province (VVP), located in the western branch of the East African Rift System, hosts a variety of alkaline lavas erupted from closely spaced volcanic centers. However, the magmatic system of this region, particularly in its eastern sector, remains insufficiently constrained. In this study, we present a petrological and geochemical investigation of basaltic to trachytic lavas from the eastern VVP. Thermobarometric analysis of mineral phases indicates that basalts originated from magma storage zones between 4 and 30 km deep, with crystallization temperatures of ~1200 °C and melt H2O contents lower than 1 wt%. In contrast, more evolved magmas crystallized at similar depths, but at lower temperatures (~1050 °C) and higher H2O contents, ranging from 2 to 4 wt%. Thermodynamic modelling suggests that extensive (up to 70%) fractional crystallization of an assemblage dominated by olivine, clinopyroxene, and plagioclase can produce the more evolved trachytic derivatives from basaltic parental melts. When integrated with previous studies from other VVP volcanoes, our findings deepen the understanding of the architecture of the magmatic system beneath the region, suggesting it resembles a well-developed multi-level plumbing system. Full article
(This article belongs to the Special Issue Trans-Crustal Evolution of Magmas: Clues from Thermodynamic and Geochemical Modelling, Thermo-Barometry and Experimental Petrology)
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23 pages, 11397 KB  
Article
Tectonic Evolution of Wadi Hebran Area on the Suez Rift Eastern Flank, Sinai, Egypt
by Sherif Mansour, Amr Elkelish, Abdullah S. Alawam, Mohamed A. Gharib, Akihiro Tamura and Noriko Hasebe
Minerals 2025, 15(6), 655; https://doi.org/10.3390/min15060655 - 18 Jun 2025
Viewed by 797
Abstract
Continental rifts represent one of the most important settings geologically and economically. The Suez Rift represents more than 74% of the Egyptian crude oil. It represents the northern end of the Red Sea, which understanding is vital to reconstructing the tectonics, dynamics, and [...] Read more.
Continental rifts represent one of the most important settings geologically and economically. The Suez Rift represents more than 74% of the Egyptian crude oil. It represents the northern end of the Red Sea, which understanding is vital to reconstructing the tectonics, dynamics, and time–temperature history of the whole region. An effective method to reveal rift-related history is by studying its flanks, which are represented here by the Arabian-Nubian Shield Neoproterozoic basement rocks. We applied an approach integrating new fission-track thermochronology data, new time–temperature modeling, stratigraphic information, and geological knowledge, which has proven its effectiveness in such geological settings. The collected samples from the Wadi Hebran area on the eastern flank of the Suez rift showed two differentiated cooling histories: The first has a Carboniferous zircon fission-track and a Cretaceous apatite fission-track age, and the second has a Triassic zircon fission-track and an Oligocene–Miocene apatite fission-track age. The time–temperature history modeling supported four distinct cooling events activated through the Neoproterozoic post-accretion erosional event, Variscan tectonic event, Gondwana disintegration, and the Suez Rift initiation. The rock uplift that accompanied the Suez Rift reaches up to 4 km, explaining the extraordinary elevations of the Catherina region, and supports an active rift component in the southern segment of the Suez Rift eastern flank. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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11 pages, 1410 KB  
Article
Theoretical Study on Impact of Chemical Composition and Water Content on Mechanical Properties of Stratlingite Mineral
by Daniel Tunega and Ali Zaoui
Minerals 2025, 15(6), 648; https://doi.org/10.3390/min15060648 - 16 Jun 2025
Viewed by 356
Abstract
Stratlingite is known as one of the hydration products of aluminum-rich cements. Its microstructure and, consequently, mechanical properties, depend on the Al/Si ratio and hydration conditions. The layered structure of stratlingite is characterized as defected, with vacancies in the aluminosilicate layer. This study [...] Read more.
Stratlingite is known as one of the hydration products of aluminum-rich cements. Its microstructure and, consequently, mechanical properties, depend on the Al/Si ratio and hydration conditions. The layered structure of stratlingite is characterized as defected, with vacancies in the aluminosilicate layer. This study uses density functional theory calculations on different stratlingite models to show how chemical composition, water content, and structural defects affect its mechanical properties. The developed models represent structures with full occupancy, with little or no content of structural water, and with vacancies in the aluminosilicate layer. It was shown that the full occupancy models have the highest toughness and are strongly anisotropic. The calculated bulk modulus (BH) of the models with full occupancy was about 40 GPa, being in the typical range for calcium aluminosilicate minerals. The water loss led to an increase in BH by approximately 40% compared to the models with full occupancy. In contrast, the models with vacancies exhibited a decrease in BH of about 30%. In models with the high silicon content (Al/Si ratio of 1/4), BH, Young’s (EH), and shear (GH) moduli decreased in a range 15%–30% compared to the models with an Al/Si ratio of 2/3 of Al/Si. Finally, according to Pugh’s ratio (BH/GH), which serves as a criterion for brittle–ductile transition (1.8), the models with full occupancy exhibit a brittle behavior, whereas the defected structures are closer to ductile. This could explain the elastic behavior of stratlingite binder in concretes. Generally, the calculations showed that all investigated parameters (chemical composition, water content, and structural defects) have a significant impact on the mechanical properties of stratlingite minerals. Full article
(This article belongs to the Section Clays and Engineered Mineral Materials)
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29 pages, 4559 KB  
Article
Revisiting the Permian Stratigraphy of the Kuznetsk Coal Basin (Siberia, Russia) Using Radioisotopic Data: Sedimentology, Biotic Events, and Palaeoclimate
by Vladimir V. Silantiev, Yaroslav M. Gutak, Marion Tichomirowa, Alexandra Käßner, Anna V. Kulikova, Sergey I. Arbuzov, Nouria G. Nourgalieva, Eugeny V. Karasev, Anastasia S. Felker, Maria A. Naumcheva, Aleksandr S. Bakaev, Lyubov G. Porokhovnichenko, Nikolai A. Eliseev, Veronika V. Zharinova, Dinara N. Miftakhutdinova and Milyausha N. Urazaeva
Minerals 2025, 15(6), 643; https://doi.org/10.3390/min15060643 - 13 Jun 2025
Viewed by 683
Abstract
The radioisotopic dating of five stratigraphic levels within the Permian succession of the Kuznetsk Coal Basin refined the ages of the corresponding stratigraphic units and, for the first time, enabled their direct correlation with the International Chronostratigraphic Chart, 2024. The analysis revealed significant [...] Read more.
The radioisotopic dating of five stratigraphic levels within the Permian succession of the Kuznetsk Coal Basin refined the ages of the corresponding stratigraphic units and, for the first time, enabled their direct correlation with the International Chronostratigraphic Chart, 2024. The analysis revealed significant discrepancies between the updated ages and the previously accepted regional scheme (1982–1996). A comparison of regional stratigraphic units’ durations with estimated coal and siliciclastic sediment accumulation rates indicated that the early Permian contains the most prolonged stratigraphic hiatuses. The updated stratigraphic framework enabled re-evaluating the temporal sequence of regional sedimentological, volcano–tectonic and biotic events, allowing for more accurate comparison with the global record. Palaeoclimate reconstructions indicated that during the early Permian, the Kuznetsk Basin was characterised by a relatively warm, humid, and aseasonal climate, consistent with its mid-latitude position during the Late Palaeozoic Ice Age. In contrast, the middle-to-late Permian shows a transition to a temperate, moderately humid climate with pronounced seasonality, differing from the warmhouse conditions of low-latitude palaeoequatorial regions. The latest Lopingian reveals a distinct trend toward increasing dryness, consistent with global palaeoclimate signals associated with the end-Permian crisis. Full article
(This article belongs to the Special Issue Sedimentary Basins and Minerals)
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19 pages, 11500 KB  
Article
Continental Rift Driven by Asthenosphere Flow and Lithosphere Weakening by Flood Basalts: South America and Africa Cenozoic Rifting
by Ingo L. Stotz, Berta Vilacís, Jorge N. Hayek and Hans-Peter Bunge
Minerals 2025, 15(6), 644; https://doi.org/10.3390/min15060644 - 13 Jun 2025
Viewed by 631
Abstract
Continental rifting is the process by which land masses separate and create new ocean basins. The emplacement of large igneous provinces (LIPs) is thought to have played a key role in (super) continental rifting; however, this relationship remains controversial due to the lack [...] Read more.
Continental rifting is the process by which land masses separate and create new ocean basins. The emplacement of large igneous provinces (LIPs) is thought to have played a key role in (super) continental rifting; however, this relationship remains controversial due to the lack of a clearly established mechanism linking LIP emplacement to continental fragmentation. Here, we show that plume flow links LIP magmatism to continental rifting quantitatively. Our findings are further supported by the sedimentary record, as well as by the mineralogy and petrology of the rocks. This study analyzes the early Cretaceous separation of West Gondwana into South America and Africa. Prior to rifting, Jurassic hiatuses in the stratigraphic record of continental sediments from both continents indicate plume ascent and the resulting dynamic topography. Cretaceous mafic dyke swarms and sill intrusions are products of major magmatic events that coincided with continental rifting, leading to the formation of large igneous provinces in South America and Africa, including the Central Atlantic Magmatic Province, Equatorial Magmatic Province, Paraná–Etendeka, and Karoo. It has been suggested that dyke intrusions may weaken the lithosphere by reducing its mechanical strength, creating structural weaknesses that localize extensional deformation and facilitate rift initiation. The sedimentary analysis and petrological evidence from flood basalt magmas indicate that plumes may have migrated from the depths toward the surface during the Jurassic and erupted during the Cretaceous. It is thought that the resulting fast plume flow, induced by one or more mantle plumes, generated a dynamic force that, in combination with lithospheric weakening from dyke intrusion, eventually rifted the lithosphere of West Gondwana. Full article
(This article belongs to the Special Issue Large Igneous Provinces: Research Frontiers)
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17 pages, 3986 KB  
Article
Geo-Identity of the Most Exploited Underground Obsidian Deposit in Mesoamerica: Cartography, Petrography, and Geochemistry of the Sierra de las Navajas, Hidalgo, Mexico
by Gerardo Alonso López-Velarde, Jesús Roberto Vidal-Solano and Alejandro Pastrana
Minerals 2025, 15(6), 629; https://doi.org/10.3390/min15060629 - 10 Jun 2025
Viewed by 668
Abstract
The Sierra de las Navajas is a Late Pliocene volcanic complex with a rhyolitic composition and peralkaline affinity. It is located on the northeastern edge of the Trans-Mexican Volcanic Belt in the state of Hidalgo. Within this rocky massif lies Cerro de las [...] Read more.
The Sierra de las Navajas is a Late Pliocene volcanic complex with a rhyolitic composition and peralkaline affinity. It is located on the northeastern edge of the Trans-Mexican Volcanic Belt in the state of Hidalgo. Within this rocky massif lies Cerro de las Navajas, the site of the most intensively exploited archaeological obsidian deposit in Mesoamerica. Obsidian extraction in this area has been carried out through open-pit mining and unique underground mining. The geological identity of the deposit encompasses the origin, distribution, and petrological characteristics of the obsidian from Cerro de las Navajas, determined through detailed geological mapping, petrographic study, and geochemical analysis. The results reveal the obsidian deposit’s style as well as its temporal and spatial position within the eruptive evolution of the region. The deposit originated from a local explosive eruptive mechanism associated with the partial collapse of a lava dome, forming a Block and Ash Flow Deposit (BAFD). The obsidian blocks, exploited by different cultures, correspond to the pyroclastic blocks within this deposit, which can reach up to 1 m in diameter and are embedded in a weakly consolidated ash matrix. The BAFD was later buried by (a) subsequent volcanic events, (b) structural adjustments of the volcanic edifice, and (c) soils derived from the erosion of other volcanic units. This obsidian deposit was mined underground from the Early Formative period to the Colonial era by the cultures of the Central Highlands and colonized societies. Interest in the vitreous quality and exotic nature of obsidian lithics from the BAFD led to the development of a complex exploitation system, which was generationally refined by the Teotihuacan, Toltec, and Aztec states. Full article
(This article belongs to the Special Issue Characterization and Provenance Analysis of Ancient Stone Materials: Insights from Mineralogy, Petrology and Geochemistry)
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17 pages, 7055 KB  
Article
Effects of Grinding Parameters on Galena Particle Size Distribution and Flotation Performance
by Mengchi Guo, Yuankun Yang, Shengli Yu, Yanming Wu, Guohua Gu, Yanhong Wang, Qingke Li and Jianyu Chen
Minerals 2025, 15(6), 618; https://doi.org/10.3390/min15060618 - 9 Jun 2025
Cited by 1 | Viewed by 563
Abstract
The processing of low-grade, lead-containing practical ores requires fine grinding to liberate galena and enhance flotation recovery. The ball mill is still one of the most common approaches used in industry for fine grinding. This study investigated the effect of the grinding parameters [...] Read more.
The processing of low-grade, lead-containing practical ores requires fine grinding to liberate galena and enhance flotation recovery. The ball mill is still one of the most common approaches used in industry for fine grinding. This study investigated the effect of the grinding parameters in a ball mill on the fine grinding product of galena and on flotation performance. The grinding product had a particle size below 30 μm, which was classified into +25 μm, −25 + 10 μm, and −10 μm fractions. Grinding experiments showed that modifications to the grinding concentration, media proportion, and filling ratio exerted significant effects on the yields of the +25 μm and −10 μm fractions. Flotation experiments showed that the yield of −10 μm particles negatively affected the flotation performance of galena. Discrete element method simulation results revealed that an increase in the motion velocity of the media group enhanced attrition effects during fine grinding, promoting the generation of −10 μm particles. The higher yield of −10 μm particles facilitated a smaller contact angle and smaller agglomerate size, resulting in lower recovery. To optimize the particle size distribution and improve fine-grained galena flotation recovery, it is essential to reduce the attrition of the grinding media on the mineral. Full article
(This article belongs to the Special Issue Advances in the Theory and Technology of Physical Separation)
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16 pages, 6672 KB  
Article
Lithology and Macroscopic Coal Lithotype Identification of Coal-Bearing Measures Based on Elemental Mud Logging: A Case Study of the Eastern Ordos Basin Coal Seam
by Yuejiao Liu, Wenya Zhang, Fuqiang Lai, Mingyang Zhang, Honghua Sun, Zongsheng Zhou, Jianmeng Sun, Ruyue Wang and Shanshan Zheng
Minerals 2025, 15(6), 616; https://doi.org/10.3390/min15060616 - 9 Jun 2025
Viewed by 365
Abstract
China is rich in coalbed methane (CBM) resources, and the key to realizing the scale and efficiency of CBM development is to build “engineering tools” for exploration and development continuously. Accurate calculation of rock components and precise identification of lithology and macroscopic coal [...] Read more.
China is rich in coalbed methane (CBM) resources, and the key to realizing the scale and efficiency of CBM development is to build “engineering tools” for exploration and development continuously. Accurate calculation of rock components and precise identification of lithology and macroscopic coal lithotypes of coal-bearing measures are the basis for the evaluation of CBM geological engineering. This paper proposes a method to identify the lithology and macroscopic coal lithotypes of coal-bearing measures based on elemental mud logging. Firstly, a coal seam demarcation line is constructed based on the elemental mud logging to divide the coal and non-coal seams. Secondly, the content of each component in the coal and non-coal seams is calculated. Finally, based on the results of the calculations, a method for recognizing the lithology of non-coal seams and macroscopic coal lithotypes of coal seams is constructed based on the combination of the S (sulfur) element innovatively. The calculation error of mineral and proximate analysis components is less than 10%, and the average accuracy of lithology and macroscopic coal lithotype identification is as high as 87%. The results can provide important technical guidance for the geological evaluation of coal-bearing measures and the selection of target seams. Full article
(This article belongs to the Special Issue Mineralogical and Geochemical Characteristics of Coal and Coal-Bearing Strata)
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36 pages, 13118 KB  
Article
Geochemical Halos in Wall Rocks and Overlying Soils as Indicators of Concealed Lithium Pegmatites
by Mona-Liza C. Sirbescu, Teagan R. Cox, Luiza M. P. Pierangeli, Joy O. Youngblood, David C. Weindorf and Thomas R. Benson
Minerals 2025, 15(6), 615; https://doi.org/10.3390/min15060615 - 8 Jun 2025
Cited by 3 | Viewed by 1224
Abstract
Spodumene-bearing pegmatites are geochemically anomalous among crystalline rocks and important critical mineral resources in the green energy transition. However, prospecting is challenging due to their small size and the fact that they are often covered by soil and vegetation. This study demonstrates that, [...] Read more.
Spodumene-bearing pegmatites are geochemically anomalous among crystalline rocks and important critical mineral resources in the green energy transition. However, prospecting is challenging due to their small size and the fact that they are often covered by soil and vegetation. This study demonstrates that, rather than being a hindrance, soil cover can enhance geochemical exploration, at least at the prospect scale. This study examines the dispersion pathways of lithium (Li) and its pathfinder elements (Rb, B, Ga, and Sn) from pegmatites (<10 m thick) into metamorphic host rocks and further into overlying undisturbed soils in heavily forested, postglaciated terrain of northeastern Wisconsin, USA. Soil-sample traverses over the world-renowned, lepidolite-type Animikie Red Ace pegmatite and two nearby dikes reveal pronounced <20 m anomalies with up to 1400 ppm of Li, 450 ppm of Rb, 3100 ppm of B, 40 ppm of Ga, and 60 ppm of Sn, greatly exceeding the control soil concentrations from nonmineralized granite and pegmatites. Soils mirror both the magmatic fractionation and alteration of pegmatite bedrock and metasomatic halos in parent host rocks. Metasomatized amphibolite revealed the presence of a holmquistite-ferro-holmquistite mineral. This greenfield pilot exploration led to lithium-rich pegmatite discoveries within the district and demonstrates the applicability of proximal sensors for soil exploration in Wisconsin and beyond. Full article
(This article belongs to the Special Issue Pegmatites as Hosts of Critical Metals: From Petrogenesis to Mineral Exploration)
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18 pages, 8075 KB  
Article
Kinetic Aspects of Chrysotile Asbestos Thermal Decomposition Process
by Robert Kusiorowski, Anna Gerle, Magdalena Kujawa and Andrea Bloise
Minerals 2025, 15(6), 609; https://doi.org/10.3390/min15060609 - 5 Jun 2025
Cited by 1 | Viewed by 645
Abstract
Growing requirements in the field of environmental protection and waste management result in the need to search for new and effective methods of recycling various types of waste. From the perspective of technical and natural sciences, the disposal of hazardous waste, which can [...] Read more.
Growing requirements in the field of environmental protection and waste management result in the need to search for new and effective methods of recycling various types of waste. From the perspective of technical and natural sciences, the disposal of hazardous waste, which can lead to environmental degradation, is of utmost importance. A particularly hazardous waste is asbestos, used until recently in many branches of the economy and industry. Despite the ban on the production and use of asbestos introduced in many countries, products containing it are still present in the environment and pose a real threat. This paper presents the results of research related to the process of asbestos neutralization, especially the chrysotile variety, by the thermal decomposition method. Changes in the mineralogical characteristics of asbestos waste were studied using the following methods: TG-DTA-EGA, XRD, SEM-EDS and XRF. The characteristics of the chrysotile asbestos sample were determined before and after thermal treatment at selected temperatures. The second part of the study focuses on the kinetic aspect of this process, where the chrysotile thermal decomposition process was measured by two techniques: ex situ and in situ. This study showed that the chrysotile structure collapsed at approximately 600–800 °C through dehydroxylation, and then the fibrous chrysotile asbestos was transformed into new mineral phases, such as forsterite and enstatite. The formation of forsterite was observed at temperatures below 1000 °C, while enstatite was created above this temperature. From the kinetic point of view, the chrysotile thermal decomposition process could be described by the Avrami–Erofeev model, and the calculated activation energy values were ~180 kJ mol−1 and ~220 kJ mol−1 for ex situ and in situ processes, respectively. The obtained results indicate that the thermal method can be successfully used to detoxify hazardous chrysotile asbestos fibers. Full article
(This article belongs to the Special Issue Recycling of Industrial Waste for the Development of Sustainable Materials)
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16 pages, 1871 KB  
Article
Prediction of Circulation Load of Side-Flanged High-Pressure Grinding Rolls Closed-Circuit Crushing
by Nan Li, Lixia Li, Jiaqi Wang, Zhe Liu, Quan Feng, Qiang Zhang, Hui Liu, Bern Klein and Bing Li
Minerals 2025, 15(6), 603; https://doi.org/10.3390/min15060603 - 4 Jun 2025
Viewed by 408
Abstract
To enhance the performance of the combined high-pressure grinding roller (HPGR) and tower mill (TM) process for −1 mm particle size, this study addresses the key technical challenges of insufficient material quantity (<100 kg) and complex experimental procedures in HPGR closed-circuit crushing tests [...] Read more.
To enhance the performance of the combined high-pressure grinding roller (HPGR) and tower mill (TM) process for −1 mm particle size, this study addresses the key technical challenges of insufficient material quantity (<100 kg) and complex experimental procedures in HPGR closed-circuit crushing tests by proposing a novel circulating load prediction method based on the principle of mass balance and first-order crushing kinetics. Using a side-flanged HPGR WGM 6020 installation, systematic −1 mm HPGR closed-circuit crushing tests were conducted on seven different ore samples under three specific pressing forces, with detailed characterization of the dynamic variations in product size distribution, specific energy consumption, and circulating load during each cycle. The results demonstrate that within the specific pressing force range of 3.5 N/mm2 to 4.5 N/mm2 when the crushing process reaches equilibrium, the circulating load stabilizes between 100% and 200%, while the specific energy consumption is maintained within 1–2.5 kWh/t. Notably, at the specific pressing force of 4.5 N/mm2, both the circulating load and specific energy consumption rapidly achieve stable states, with ore characteristics showing no significant influence on the number of cycles. To validate the model accuracy, additional samples were tested for comparative analysis, revealing that the deviations between the model-predicted −1 mm product content and circulating load and the experimental results were less than ±5%, confirming the reliability of the proposed method. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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17 pages, 1581 KB  
Article
Advancing Flotation Process Modeling: Bayesian vs. Sklearn Approaches for Gold Grade Prediction
by Sheila Devasahayam
Minerals 2025, 15(6), 591; https://doi.org/10.3390/min15060591 - 31 May 2025
Cited by 2 | Viewed by 582
Abstract
This study explores Bayesian Ridge Regression and PyMC-based probabilistic modelling to predict the cumulative grade of gold based on key operational variables in gold flotation. By integrating prior knowledge and quantifying uncertainty, the Bayesian approach enhances both interpretability and predictive accuracy. The dataset [...] Read more.
This study explores Bayesian Ridge Regression and PyMC-based probabilistic modelling to predict the cumulative grade of gold based on key operational variables in gold flotation. By integrating prior knowledge and quantifying uncertainty, the Bayesian approach enhances both interpretability and predictive accuracy. The dataset includes variables such as crusher type, particle size, power, time, head grade, and collector type. Comparative analysis reveals that PyMC outperforms traditional Sklearn models, achieving an R2 of 0.92 and an MSE of 102.37. These findings highlight the potential of Bayesian models for robust, data-driven process optimization in mineral processing. The higher cumulative gold grade observed for VSI products and PAX collector usage may be attributed to the superior liberation efficiency of VSI, which produces more angular and cleanly fractured particles, enhancing collector attachment. PAX, being a strong xanthate, shows high affinity for sulphide mineral surfaces, particularly under the flotation conditions used, thereby improving selectivity and recovery. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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15 pages, 2858 KB  
Article
Surface Physicochemical Property Differences Between Gold-Bearing and Gold-Free Pyrite for Efficient and Clean Processing of Refractory Pyritic Gold Ores
by Xujian Chai, Runqing Liu, Wenchao Dong, Wei Sun and Shangyong Lin
Minerals 2025, 15(6), 577; https://doi.org/10.3390/min15060577 - 29 May 2025
Viewed by 510
Abstract
Selective separation of gold-bearing pyrite from gold-free pyrite through flotation to improve the gold-to-sulfur ratio in the feed can significantly enhance the throughput of autoclaves, thus achieving efficient and clean processing of refractory pyritic gold ores. To achieve this expectation, this study examined [...] Read more.
Selective separation of gold-bearing pyrite from gold-free pyrite through flotation to improve the gold-to-sulfur ratio in the feed can significantly enhance the throughput of autoclaves, thus achieving efficient and clean processing of refractory pyritic gold ores. To achieve this expectation, this study examined the surface physicochemical differences between gold-bearing and gold-free pyrite under flotation conditions using cyclic voltammetry, polarization curve testing, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) simulations. Electrochemical tests showed higher reactivity in gold-bearing pyrite, with reactivity positively correlated to gold content. XPS results indicated more oxidation products on gold-bearing pyrite surfaces under identical conditions. DFT simulations revealed that the presence of gold reduced the oxygen adsorption energy on the pyrite surface while enhancing interactions between oxygen atoms and sulfur and iron atoms. Based on these findings, the selective separation of gold-bearing and gold-free pyrite in the flotation process can be explored through pulp aeration pre-oxidation combined with collectors demonstrating selectivity toward barren pyrite (e.g., dithiocarbamate collectors). This study provides theoretical foundations for the efficient exploitation and utilization of refractory gold-bearing pyrite resources. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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14 pages, 7485 KB  
Article
Supported Hybrid Amines Within Porous Aluminosilicate Clays with Natural Different Morphologies for Efficient CO2 Capture
by Xiaoyu Li, Jie Chen, Wenqing Zhang, Chenyu Wang, Hui Ma, Kang Peng and Zheng Zhou
Minerals 2025, 15(5), 506; https://doi.org/10.3390/min15050506 - 9 May 2025
Viewed by 678
Abstract
The urgent need for efficient CO2 capture technologies has driven research into amine-functionalized adsorbents, though existing methods face trade-offs between adsorption capacity and cycling stability. This study addresses these limitations by developing a novel hybrid modification strategy combining chemical grafting and physical [...] Read more.
The urgent need for efficient CO2 capture technologies has driven research into amine-functionalized adsorbents, though existing methods face trade-offs between adsorption capacity and cycling stability. This study addresses these limitations by developing a novel hybrid modification strategy combining chemical grafting and physical impregnation on polymorphic kaolinite minerals. Through systematic acid leaching and hybrid grafting–impregnation amine functionalization, the adsorbents with hierarchically porous structures and optimized performances are synthesized. The tubular adsorbent (ATK-APTES-PEI) demonstrated exceptional performance, achieving a CO2 uptake of 1.68 mmol/g at 75 °C under a 60% CO2/40% N2 mixed gas flow, with only 5.3% capacity loss after 10 adsorption–desorption cycles, significantly outperforming both rod-like (ARK-APTES-PEI, 1.55 mmol/g) and flake-like (AFK-APTES-PEI, 1.23 mmol/g) variants. The unique pore structure of ATK-APTES-PEI enables simultaneous high amine loading and maintained gas diffusion pathways, while the hybrid modification strategy synergistically enhances both adsorption capacity and stability by increasing active surface sites. These findings establish critical structure–property relationships for mineral-based adsorbents and demonstrate a scalable approach for industrial CO2 capture applications. The work provides a blueprint for designing cost-effective, stable adsorbents using abundant clay minerals, bridging materials science with environmental engineering for sustainable carbon management solutions. Full article
(This article belongs to the Special Issue Clay Minerals and CO2 Capture, Utilization and Storage)
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15 pages, 5368 KB  
Article
Radioiodide Sorption on Natural and Acid-Treated Zeolite
by Petr Belousov, Ekaterina Tyupina, Pavel Kozlov, Yulia Izosimova, Inna Tolpeshta, Tatiana Koroleva, Boris Pokidko, Victoria Krupskaya and Anastasia Rumyantseva
Minerals 2025, 15(5), 494; https://doi.org/10.3390/min15050494 - 7 May 2025
Viewed by 575
Abstract
This work is devoted to the study of the effect of acid treatment on the structural and textural properties of natural zeolite and its sorption activity with respect to radioiodide. To carry out the experiments, natural zeolite was treated with nitric acid of [...] Read more.
This work is devoted to the study of the effect of acid treatment on the structural and textural properties of natural zeolite and its sorption activity with respect to radioiodide. To carry out the experiments, natural zeolite was treated with nitric acid of various concentrations at 20 and 90 degrees. The following methods were used to study the samples: XRD, SEM, DTA, XRF, FTIR, BET, and CEC analyses. Experiments on the sorption and desorption of radioiodide were carried out. The obtained results indicate that acid treatment results in the gradual leaching of aluminum from the crystal lattice and a significant increase in the specific surface area and microporosity of the zeolite. At the same time, the morphology of clinoptilolite is not significantly changed. Additional studies have shown that acid treatment leads to the hydrophobization of zeolite channels and the formation of an amorphous aluminosilicate phase, which makes a significant contribution to the increase in the specific surface area and microporosity. It was found that, with an increase in the degree of dealumination of the zeolite, there is an increase in the sorption properties with respect to radioiodide. The maximum values of sorption capacity were obtained after treating the zeolite with a 1 M nitric acid solution at 90 °C. With a further increase in the concentration of acid, critical changes in the structure of the zeolite occur, leading to a sharp decrease in the sorption capacity. Iodide sorption is not associated with physical adsorption in the micropores of the zeolite and the newly formed amorphous phase. The main mechanism of the sorption appears to be the interaction with silanol and bridging hydroxyl groups on the surface of the zeolite and the amorphous aluminosilicate phase. Full article
(This article belongs to the Special Issue Zeolite: From a Boiling Stone to the Applicable Minerals in Various Industrial Processes: 2nd Edition)
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16 pages, 7745 KB  
Article
Investigation of a Novel Depressant for Flotation Separation of Chalcopyrite and Galena: Experiments and Adsorption Mechanisms
by Hong Zeng, Chongjun Liu, Tong Lu, Zehui Gao, Yangge Zhu, Chuanyao Sun, Zhiqiang Zhao, Guiye Wu, Ruidong Li and Jun Hu
Minerals 2025, 15(5), 454; https://doi.org/10.3390/min15050454 - 27 Apr 2025
Cited by 1 | Viewed by 535
Abstract
To reduce lead content in copper concentrates, this study developed a novel galena depressant, TA (thioureidoacetic acid). This study utilizes a synthetic mineral feed with fully liberated galena and chalcopyrite from separate sources to establish baseline separation conditions. The adsorption capability of TA [...] Read more.
To reduce lead content in copper concentrates, this study developed a novel galena depressant, TA (thioureidoacetic acid). This study utilizes a synthetic mineral feed with fully liberated galena and chalcopyrite from separate sources to establish baseline separation conditions. The adsorption capability of TA on galena surfaces was systematically investigated through micro-flotation tests, surface characterization, and first-principles calculations. Results demonstrate that TA effectively reduces galena recovery (from 82.92% to 12.29%) without compromising chalcopyrite flotation efficiency (>83.2% recovery) when using thionocarbamate (Z200) as the collector. FTIR and XPS analyses confirm that TA chemisorbs onto galena surfaces via its C=S and C=O functional groups. First-principles calculations reveal dual Pb-S and Pb-O bond formation during TA adsorption, resulting in stronger interfacial binding energy compared to Z200. This work establishes a molecular engineering framework for designing high-selectivity depressants. Full article
(This article belongs to the Special Issue Advances in Flotation of Copper, Lead and Zinc Minerals)
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24 pages, 13891 KB  
Article
Fertility of Gabbroic Intrusions in the Paleoproterozoic Lynn Lake Greenstone Belt, Manitoba, Canada: Insights from Field Relationships, Geochemical and Metallogenic Characteristics
by Xue-Ming Yang
Minerals 2025, 15(5), 448; https://doi.org/10.3390/min15050448 - 26 Apr 2025
Viewed by 767
Abstract
Magmatic nickel–copper–platinum group element (PGE) deposits hosted in mafic–ultramafic intrusions within volcanic arc systems are highly attractive targets for mineral exploration, yet their genesis remains poorly understood. This study investigates metagabbroic intrusions in the Paleoproterozoic Lynn Lake greenstone belt of the Trans-Hudson Orogen [...] Read more.
Magmatic nickel–copper–platinum group element (PGE) deposits hosted in mafic–ultramafic intrusions within volcanic arc systems are highly attractive targets for mineral exploration, yet their genesis remains poorly understood. This study investigates metagabbroic intrusions in the Paleoproterozoic Lynn Lake greenstone belt of the Trans-Hudson Orogen to identify the key factors, in the original gabbros, that control the formation of magmatic Ni-Cu-PGE deposits in volcanic arc systems. By examining the field relationships, geochemical and sulfur and oxygen stable isotope compositions, mineralogy, and structural fabrics, this study aims to explain why some intrusions host mineralization (e.g., Lynn Lake and Fraser Lake intrusions), whereas others remain barren (e.g., Ralph Lake, Cartwright Lake, and Snake Lake intrusions). Although both the fertile and barren gabbroic, likewise original, intrusions exhibit metaluminous, tholeiitic to calc-alkaline affinity with volcanic arc geochemical signatures, they differ significantly in shape, ranging from vertical and tube-like to tabular forms, reflecting distinct geological settings and magma dynamics. The gabbroic rocks of fertile intrusions exhibit erratic trace element profiles, lower (Nb/Th)N and higher (Cu/Zr)N ratios, as well as a larger range of δ34S values than those in barren intrusions. Key factors influencing Ni-Cu-PGE mineralization include the degree of partial melting of the mantle, early sulfide segregation, and crustal contamination, particularly from volcanogenic massive sulfide deposits. These processes likely triggered sulfide saturation in the mafic magmas. Geochemical proxies, such as PGE concentrations and sulfur and oxygen stable isotopes, provide critical insights into these controlling factors. The results of this study enhance our understanding of the metallogenic processes responsible for the formation of magmatic Ni-Cu-PGE deposits in the gabbroic intrusions emplaced in an extensional setting due to slab rollback, during the geological evolution of the Lynn Lake greenstone belt, offering valuable guidance for mineral exploration efforts. Full article
(This article belongs to the Special Issue Novel Methods and Applications for Mineral Exploration, Volume III)
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23 pages, 16107 KB  
Article
Utilizing Lineaments Extracted from Radar Images and Drainage Network to Evaluate the Mineral Potential of Au and Cu in the Bom Jardim Group (Neoproterozoic), Southern Brazil
by Marco Antonio Fontoura Hansen, César Augusto Moreira, Henri Masquelin, José Pedro Rebés Lima, Lenon Melo Ilha, Luiza Lima Alves, Sissa Kumaira and Ana Flávia da S. Araújo
Minerals 2025, 15(5), 436; https://doi.org/10.3390/min15050436 - 23 Apr 2025
Viewed by 1421
Abstract
The exploration of gold and copper is essential for the sustainable development of mining worldwide and in Brazil, given the dependency on copper imports. This study aims to reassess and identify promising areas for sulfide prospecting in southern Brazil, with technologies, including radar [...] Read more.
The exploration of gold and copper is essential for the sustainable development of mining worldwide and in Brazil, given the dependency on copper imports. This study aims to reassess and identify promising areas for sulfide prospecting in southern Brazil, with technologies, including radar images (ALOS PALSAR) and software (PCI Geomatics CATALYST Professional Complete, version 2023, QGIS 3.38.1 (Grenoble), Spring 5.5.6, and Orient 3.20.0), for the extraction and processing of tectonic lineaments. The comparative analysis between these linear structures and the drainage networks allows for the assessment of alluvial gold minerals and disseminated copper in andesites, as observed in the abandoned Seival mines. The methods employed include the extraction of tectonic lineaments and the evaluation of mineral occurrences in the Hilário (volcanogenic) and Arroio dos Nobres (sedimentary) formations of the Bom Jardim Group (Neoproterozoic) and their drainage networks. As a result, this article concludes that the main tectonic alignment directions for copper and gold occurrences disseminated in andesites are predominantly E–W, N–S, N 5° W, N 58° W, N 62° E, and N 23° E, and for alluvial gold N–S and N 45° W. These results are crucial for reassessing abandoned mining areas and identifying the primary mineral orientations in rocks and the predominant orientation of alluvial deposits, serving as structural controls for discovering new mineral occurrences. It is concluded that geotechnologies have expanded the possibilities for study, enabling a more detailed analysis of tectonic lineaments and drainage systems and providing a valuable prospective guide for gold and copper mineral exploration. Full article
(This article belongs to the Special Issue Geophysical Signatures of Mineral Deposits in Tropical and Subtropical Settings)
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26 pages, 7042 KB  
Article
Thermodynamic Stability of Clay Minerals in Boreal Forest Soil and Its Relationship to the Properties of Soil Organic Matter
by Igor V. Danilin, Yulia G. Izosimova, Ruslan A. Aimaletdinov and Inna I. Tolpeshta
Minerals 2025, 15(4), 430; https://doi.org/10.3390/min15040430 - 20 Apr 2025
Viewed by 513
Abstract
This paper assesses the thermodynamic stability of clay minerals in the upper organo-mineral horizon of podzolic soil, as well as in the rhizosphere of Norway spruce (Picea abies (L.) H. Karst.) and Norway maple (Acer platanoides L.). Moreover, it determines the [...] Read more.
This paper assesses the thermodynamic stability of clay minerals in the upper organo-mineral horizon of podzolic soil, as well as in the rhizosphere of Norway spruce (Picea abies (L.) H. Karst.) and Norway maple (Acer platanoides L.). Moreover, it determines the impact of soil organic matter on the thermodynamic stability of clay minerals. Calculations of ΔGf and the saturation index (SI) for clay minerals in laboratory experiments simulating soil conditions without soil moisture outflow allowed us to find out that the thermodynamic stability of clay minerals decreased in the series kaolinite > illite > vermiculite > chlorite. In the rhizosphere of spruce, kaolinite, vermiculite and illite have the lowest, and in the soil under maple-the highest thermodynamic stability, which is associated with differences in the properties of soil organic matter of rhizospheres of different tree species. Laboratory experiments on the sorption of soil humic acid (HA) on clay minerals demonstrated that sorbed HA decreased the thermodynamic stability of biotite and increased the thermodynamic stability of kaolinite and muscovite. Thermodynamic stability of clay minerals decreased with increased proportion of sorbed thermolabile organic matter. Full article
(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)
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22 pages, 17789 KB  
Article
Mafic Enclaves Reveal Multi-Magma Storage and Feeding of Shangri-La Lavas at the Nevados de Chillán Volcanic Complex
by Camila Pineda, Gloria Arancibia, Valentina Mura, Diego Morata, Santiago Maza and John Browning
Minerals 2025, 15(4), 418; https://doi.org/10.3390/min15040418 - 17 Apr 2025
Cited by 1 | Viewed by 865
Abstract
The Nevados de Chillán Volcanic Complex is one of the most active of the Southern Volcanic Zone. It is formed by NW-SE-aligned eruptive centers divided into two subcomplexes, namely Cerro Blanco (basaltic andesitic) and Las Termas (dacitic), and two satellite cones (to the [...] Read more.
The Nevados de Chillán Volcanic Complex is one of the most active of the Southern Volcanic Zone. It is formed by NW-SE-aligned eruptive centers divided into two subcomplexes, namely Cerro Blanco (basaltic andesitic) and Las Termas (dacitic), and two satellite cones (to the SW and NE of the main alignment). Our study of the Shangri-La volcano, which is located between the two subcomplexes, in alignment with the satellite cones, and which produced dacitic lavas with basaltic andesitic enclaves, sheds light on the compositional and structural diversity of the volcanic complex. Detailed petrography along with mineral chemistry allows us to suggest partial hybridization between the enclaves and the host lavas and that mixing processes are related to the generation of the Shangri-La volcano and to other volcanic products generated in the complex. This is supported by mixing trends between the enclaves and the most differentiated units from Las Termas. We argue the presence of two main magma storage areas genetically related to crustal structures. A dacitic reservoir (~950 °C) is fed along NW-SE structures, whereas a deeper mafic reservoir (>1100 °C) utilizes predominantly NE-SW structures. We suggest that the intersection between these sets of structures facilitates magma ascent and controls the Nevados de Chillán plumbing system dynamics. Full article
(This article belongs to the Special Issue Magmatic Evolution through Time of Volcanic Zones: Evidence from Isotopic, Geochemical and Geochronological Data of Eruption Products)
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50 pages, 21988 KB  
Article
Transforming LCT Pegmatite Targeting Models into AI-Powered Predictive Maps of Lithium Potential for Western Australia and Ontario: Approach, Results and Implications
by Oliver P. Kreuzer and Bijan Roshanravan
Minerals 2025, 15(4), 397; https://doi.org/10.3390/min15040397 - 9 Apr 2025
Viewed by 2961
Abstract
Here, we present holistic targeting models for lithium–cesium–tantalum (LCT) pegmatites in Western Australia, the world’s largest supplier of hardrock lithium ores, and Ontario, an emerging hardrock lithium mining jurisdiction. In this study, the LCT pegmatite targeting models, informed by a review of this [...] Read more.
Here, we present holistic targeting models for lithium–cesium–tantalum (LCT) pegmatites in Western Australia, the world’s largest supplier of hardrock lithium ores, and Ontario, an emerging hardrock lithium mining jurisdiction. In this study, the LCT pegmatite targeting models, informed by a review of this deposit type and framed in the context of a mineral system approach, served to identify a set of targeting criteria that are mappable in the publicly available exploration data for Western Australia and Ontario. This approach, which formed the basis for artificial intelligence (AI)-powered mineral potential modeling (MPM), using multiple, complimentary modeling techniques, not only delivered the first published regional-scale views of lithium potential across the Archean to Proterozoic terrains of Western Australia and Ontario, but it also delivered an effective framework for exploration and revealed hidden trends. For example, we identified a statistically verifiable proximity relationship between lithium, gold, and nickel occurrences and confirmed a significant size differential between LCT pegmatites in Western Australia and Ontario, with the former typically containing much larger resources than the latter. Overall, this regional-scale targeting study served to demonstrate the power of precompetitive, high-quality geoscience data, not only for regional-scale targeting but also for the development of camp-scale targets that have the resolution to be investigated using conventional prospecting techniques. Importantly, MPM does not generate ‘treasure maps’. Rather, MPM provides another tool in the ‘exploration toolbox’, and its output should be taken as the starting point for further investigations. Full article
(This article belongs to the Special Issue Critical Metal Minerals, 2nd Edition)
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