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Minerals
Volume 15
Issue 6
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Minerals, Volume 15, Issue 6 (June 2025) – 114 articles

Cover Story (view full-size image): The current study examines rare-metal pegmatites hosted by the 1.8 Ga per-alkaline albite-enriched granite of the renowned Madeira deposit (Amazonas, Brazil). Four types are identified, all derived from magmatic fluids of the host rock. Their mineralogy reflects a rare-metal-rich paragenesis, including cryolite, polylithionite, pyrochlore, xenotime, and genthelvite. These pegmatites record a magmatic–hydrothermal evolution driven by extreme fractionation, melt–melt immiscibility, and internal fluid exsolution. The exceptionally high F content (up to 35 wt.%) played a decisive role in concentrating the strategic metals Nb, Ta, REEs (notably HREE), Li, and Be. These findings establish the Madeira system as a reference for rare-metal magmatic–hydrothermal evolution in per-alkaline granitic systems. View this paper
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22 pages, 5365 KiB  
Article
Machine Learning-Based Analysis of Heavy Metal Migration Under Acid Rain: Insights from the RF and SVM Algorithms
by Jie Yao, Jianping Qian and Dongru Ji
Minerals 2025, 15(6), 663; https://doi.org/10.3390/min15060663 - 19 Jun 2025
Viewed by 368
Abstract
Acid rain alters soil chemistry significantly and is a key driver of heavy metal pollution. This study investigates the environmental impact of acid rain-induced heavy metal migration in the Siding Lead–Zinc mining area in south China. Tailings, surrounding soils, and riverbed sediments were [...] Read more.
Acid rain alters soil chemistry significantly and is a key driver of heavy metal pollution. This study investigates the environmental impact of acid rain-induced heavy metal migration in the Siding Lead–Zinc mining area in south China. Tailings, surrounding soils, and riverbed sediments were examined through simulated acid rain soil column leaching experiments. Leachate parameters—including pH, redox potential (Eh), total dissolved solids (TDSs) and heavy metal concentrations—were used to develop machine learning models (Random Forest and Support Vector Machine) to quantify the influence of environmental factors on metal migration. The results showed that leachates were generally alkaline and reductive after leaching, with Cd, Pb, and Zn as the dominant migrating metals. Leachates from tailings and nearby soils exceeded safe drinking water standards, with significantly higher cumulative metal release than other samples. The RF model outperformed the SVM model in predicting heavy metal concentrations. Feature importance analysis revealed that, beyond sample characteristics, pH and Eh were critical factors driving metal migration. Zn and Cd showed strong sensitivity to these parameters, with pH and Eh contributing over 80% to their migration. The findings highlight that acid rain can enhance the solubility and migration of heavy metals, posing a serious threat to the quality of surrounding water and underscoring the requirement for effective mitigation strategies to protect the ecological environment in mining areas. Full article
(This article belongs to the Special Issue Environmental Geochemistry of Heavy Metals: Contamination, Impacts, and Countermeasure Strategies)
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27 pages, 4959 KiB  
Article
Factors of Bottom Sediment Variability in an Abandoned Alkaline Waste Settling Pond: Mineralogical and Geochemical Evidence
by Pavel Belkin, Sergey Blinov, Elena Drobinina, Elena Menshikova, Sergey Vaganov, Roman Perevoshchikov and Elena Tomilina
Minerals 2025, 15(6), 662; https://doi.org/10.3390/min15060662 - 19 Jun 2025
Viewed by 232
Abstract
The aim of this study is to determine the characteristics of the chemical and mineral composition of sediment layers in a technogenic settling pond. This pond is located on urban land in Berezniki (Perm Krai, Russia), outside the territory of operating industrial facilities, [...] Read more.
The aim of this study is to determine the characteristics of the chemical and mineral composition of sediment layers in a technogenic settling pond. This pond is located on urban land in Berezniki (Perm Krai, Russia), outside the territory of operating industrial facilities, and contains alkaline saline industrial wastes. The origin of this waste was related to sludge from the Solvay soda production process, which had been deposited in this pond over a long period of time. However, along with the soda waste, the pond also received wastewater from other industries. As a result, the accumulated sediment is characterized by variation in morphological properties both in depth and laterally. Five undisturbed columns were taken to study the composition of the accumulated sediment. The obtained samples were analyzed by X-ray diffraction (XRD), synchronous thermal analysis (STA), and X-ray fluorescence (XRF) analysis. The results showed that the mineral composition of bottom sediments in each layer of all studied columns is characterized by the predominance of calcite precipitated from wastewater. Along with calcite, due to the presence of magnesium and sodium in the solution, other carbonates precipitated—dolomite and soda (natron), as well as complex transitional carbonate phases (northupite and trona). Together with carbonate minerals, the chloride salts halite and sylvin, sulfate minerals gypsum and bassanite, and pyrite and nugget sulfur were established. The group of terrigenous mineral components is represented by quartz, feldspars, and aluminosilicates. The chemical composition of sediments in the upper part of the section generally corresponds to the mineral composition. In the lower sediment layers, the role of amorphous phase and non-mineral compounds increased, which was determined by the results of thermal analysis. The content of heavy metals and metalloids also increases in the middle and lower sediment layers. When categorized according to the Igeo value, an excessive degree of contamination (class 6) was observed in all investigated columns for copper content (Igeo 5.2–6.1). Chromium content corresponds to class 5 (Igeo 4.1–4.6), antimony to class 4 (Igeo 3.0–4.0), and lead, arsenic, and vanadium to classes 2 and 3 (moderately polluted and highly polluted). The data obtained on variations in the mineral and chemical composition of sediments represent the initial information for the selection of methods of accumulated waste management. Full article
(This article belongs to the Special Issue Critical Minerals and Associated Elements in Mine Effluent and Treatment Residuals: Management Strategies and Technologies for Resource Recovery)
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18 pages, 3113 KiB  
Article
Chemical Composition of Wolframite from the Porokhovskoe and Yugo-Konevskoe W Deposits (Central Urals): Implications for Fluid Evolution and Ore Genesis
by Konstantin Novoselov, Danil Rogov and Dmitry A. Artemyev
Minerals 2025, 15(6), 661; https://doi.org/10.3390/min15060661 - 19 Jun 2025
Viewed by 279
Abstract
The composition of wolframite from ores of the Porokhovskoe and Yugo-Konevskoe W greisen deposits in the Central Urals is studied using SEM-EDS and LA-ICP-MS analyses. The Porokhovskoe deposit is localized in a metamorphosed volcanosedimentary sequence of Lower Silurian age, and the Yugo-Konevskoe is [...] Read more.
The composition of wolframite from ores of the Porokhovskoe and Yugo-Konevskoe W greisen deposits in the Central Urals is studied using SEM-EDS and LA-ICP-MS analyses. The Porokhovskoe deposit is localized in a metamorphosed volcanosedimentary sequence of Lower Silurian age, and the Yugo-Konevskoe is enclosed in an eponymous granite pluton of Middle Permian–Lower Triassic age. Most studied wolframite grains belong to hűbnerite. The Fe/(Fe + Mn) value of wolframite varies in a range of 0.02–0.50. Wolframite from both deposits is enriched in Zn, Nb, and Mg. The wolframite from the Porokhovskoe deposit is enriched in V, Sc, Zn, and Mg and is depleted in Mo, U, rare earth elements (REEs), Nb, and Ta, compared to wolframite from the Yugo-Konevskoe deposit. It is suggested that this difference is due to the occurrence of ore veins in different rocks at different distance from the source of the ore-forming fluid, which cools down as it moves away from the source, leading to a decrease in the incorporation of trace elements by the lower-temperature wolframite. The predominance of heavy REEs over light REEs in all the studied wolframite is explained by the close ionic radii of heavy REEs to the main mineral-forming elements Fe and Mn. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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12 pages, 1244 KiB  
Article
Evaluation of Energy Consumption for Mineral Processing of Tungsten Ore in Mongolia: Khovd Aimag and Erdene-Soum as Case Studies
by Ha Bich Trinh, Seunghyun Kim, Taehun Son, Junkun Song and Jaeryeong Lee
Minerals 2025, 15(6), 660; https://doi.org/10.3390/min15060660 - 19 Jun 2025
Viewed by 273
Abstract
The tungsten deposits in Mongolia have the potential to be exploited as an alternative source to alleviate the risk due to the monopolization in the global production of such a critical metal. However, it is challenging to develop an efficient mineral processing method [...] Read more.
The tungsten deposits in Mongolia have the potential to be exploited as an alternative source to alleviate the risk due to the monopolization in the global production of such a critical metal. However, it is challenging to develop an efficient mineral processing method that can complement the supply based on the currently available energy resources in Mongolia. Therefore, the present study investigated the range of energy required for the beneficiation of tungsten ores, including theoretical assumptions and practical evaluation for two processes in Mongolia. The range of energy consumption was 0.12 to 2.21 kWh/t for crushing and 0.29 to 4.62 kWh/t for grinding regarding the range of Kick’s constant 0.2–0.6 kWh/t and Bond work index 7–17 kWh/t, respectively. The most dominant impact factor in the comminution was the product size. The evaluation of 18 different comminution–flotation circuits indicated a range of required energy from 362 kWh to 8298 kWh. The maximum values of energy consumption for mineral processing of Erdene-soum and Khovd Aimag tungsten ore were 6280 and 6355 kWh. An estimation regarding the energy demand (6355 kWh) and supply energy for the process of Khovd Aimag ore was conducted to propose a suitable system of renewable energy resources using the power pinch analysis method. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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19 pages, 3754 KiB  
Article
Combining Laser-Induced Breakdown Spectroscopy with the Standard Addition Method for Analyzing Impurity Elements in the Lithium Ore Mineral Spodumene
by Zeshan Adeel Umar, Sandeep Kumar, Song-Hee Han, Su-Bin Ki, Sunhye Kim, Sehoon Jung, Sang-Ho Nam and Yonghoon Lee
Minerals 2025, 15(6), 659; https://doi.org/10.3390/min15060659 - 19 Jun 2025
Viewed by 361
Abstract
Spodumene (LiAlSi2O6) is a key lithium source mineral for energy storage devices, making the accurate and rapid analysis of its elemental composition crucial for the battery industry. This study explores the use of laser-induced breakdown spectroscopy (LIBS) combined with [...] Read more.
Spodumene (LiAlSi2O6) is a key lithium source mineral for energy storage devices, making the accurate and rapid analysis of its elemental composition crucial for the battery industry. This study explores the use of laser-induced breakdown spectroscopy (LIBS) combined with the standard addition method to analyze Be, Na, and K in spodumene. The method achieved relative errors of 5%–15% compared to inductively coupled plasma optical emission spectroscopy (ICP-OES), without requiring certified standards. To ensure accuracy, non-resonance emissions were used for Be and Na to minimize self-absorption effects. Although K analysis faced challenges due to strong self-absorption in resonance emissions, focusing on weak edge intensity reduced the relative error significantly. Our results suggest that LIBS combined with the standard addition method is a promising approach for lithium ore analysis, eliminating the need for certified standard materials and complex sample preparation steps such as acid digestion and high-factor dilution. Full article
(This article belongs to the Special Issue Laser-Induced Breakdown Spectroscopy (LIBS) Applied to Determination of Rare Earth Elements and Critical Minerals)
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3 pages, 146 KiB  
Editorial
Editorial for Special Issue “Geomaterials and Cultural Heritage”
by Marco Benvenuti, Rosarosa Manca and Lucilla Fabrizi
Minerals 2025, 15(6), 658; https://doi.org/10.3390/min15060658 - 19 Jun 2025
Viewed by 168
Abstract
The Special Issue entitled “Geomaterials and Cultural Heritage” serves as a platform to gather contributions at the intersection between Heritage Science, Earth Sciences, Materials Science, and Museum Studies [...] Full article
(This article belongs to the Special Issue Geomaterials and Cultural Heritage)
33 pages, 57582 KiB  
Article
Integrating Remote Sensing and Aeromagnetic Data for Enhanced Geological Mapping at Wadi Sibrit-Urf Abu Hamam District, Southern Part of Nubian Shield
by Hatem M. El-Desoky, Waheed H. Mohamed, Ali Shebl, Wael Fahmy, Anas M. El-Sherif, Ahmed M. Abdel-Rahman, Hamed I. Mira, Mahmoud M. El-Rahmany, Fahad Alshehri, Sattam Almadani and Hamada El-Awny
Minerals 2025, 15(6), 657; https://doi.org/10.3390/min15060657 - 18 Jun 2025
Viewed by 370
Abstract
The present study aims to characterize complex geological structures and significant mineralization using remote sensing and aeromagnetic studies. Structural lineaments play a crucial role in the localization and concentration of mineral deposits. For the first time over the study district, a combination of [...] Read more.
The present study aims to characterize complex geological structures and significant mineralization using remote sensing and aeromagnetic studies. Structural lineaments play a crucial role in the localization and concentration of mineral deposits. For the first time over the study district, a combination of aeromagnetic data, Landsat 9, ASTER, and PRISMA hyperspectral data was utilized to enhance the characterization of both lithological units and structural features. Advanced image processing techniques, including false color composites, principal component analysis (PCA), independent component analysis (ICA), and SMACC, were applied to the remote sensing datasets. These methods enabled effective discrimination between Phanerozoic rock formations and the complex basement units, which comprise the island arc assemblage, Dokhan volcanics, and late-orogenic granites. The local and deep magnetic sources were separated using Gaussian filters. The Neoproterozoic basement rocks were estimated using the radial average power spectrum technique and the Euler deconvolution technique (ED). According to the RAPS technique, the average depths to shallow and deep magnetic sources are approximately 0.4 km and 1.6 km, respectively. The obtained ED contacts range in depth from 0.081 to 1.5 km. The research area revealed massive structural lineaments, particularly in the northeast and northwest sides, where a dense concentration of these lineaments was identified. The locations with the highest densities are thought to signify more fracturization in the rocks that are thought to be connected to mineralization. According to the automatic lineament extraction methods and rose diagram, NW-SE, NNE-SSW, and N-S are the major structural directions. These trends were confirmed and visually represented through textural analysis and drainage pattern control. The lithological mapping results were validated through field observations and petrographic analysis. This integrated approach has proven highly effective, showcasing significant potential for both detailed structural analysis and accurate lithological discrimination, which may be related to further mineralization exploration. Full article
(This article belongs to the Section Mineral Exploration Methods and Applications)
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25 pages, 5622 KiB  
Article
Differential Geochemical Features of Lacustrine Shale and Mudstone from Triassic Yanchang Formation, Ordos Basin, China: Insights into Their Sedimentary Environments and Organic Matter Enrichment
by Ziming Wang, Hongfei Cheng and Yang Wang
Minerals 2025, 15(6), 656; https://doi.org/10.3390/min15060656 - 18 Jun 2025
Viewed by 304
Abstract
The lacustrine mudstones and shales of the Triassic Yanchang Formation in the Ordos Basin serve as critical hydrocarbon source rocks. However, previous studies predominantly focus on individual lithologies, with comparative investigations into the sedimentary environments of dark mudstones and black shales remaining relatively [...] Read more.
The lacustrine mudstones and shales of the Triassic Yanchang Formation in the Ordos Basin serve as critical hydrocarbon source rocks. However, previous studies predominantly focus on individual lithologies, with comparative investigations into the sedimentary environments of dark mudstones and black shales remaining relatively limited. The study systematically compares sedimentary environment parameters (e.g., paleoclimate, paleosalinity, paleoredox conditions, paleowater depth, and paleoproductivity characteristics) between mudstones and shales, and how these distinct environmental factors governed the differential enrichment mechanisms of organic matter within the depositional aquatic system has been elucidated. Geochemical proxies (e.g., CIA, Sr/Cu, Rb/Sr, Sr/Ba, V/Ni, U/Th, V/Cr, Rb/Zr, P/Ti, Cu/Ti) reveal marked contrasts: In comparison with the Chang 7 and Chang 8 dark mudstones, the Chang 7 black shales exhibit (1) warmer–humid paleoclimatic regimes, (2) higher paleosalinity, (3) intensely anoxic conditions, (4) deeper paleowater depth, and (5) elevated paleoproductivity. These environmental divergences directly govern the significant total organic carbon content disparity between black shales and dark mudstones. Organic enrichment in the Chang 7 dark mudstones and black shales is primarily controlled by paleoproductivity and paleoredox conditions, with secondary influences from paleoclimate and paleowater depth. Based on the above studies, this research established a differential organic matter enrichment model. This research is of significant importance for guiding oil and gas exploration and development in the Ordos Basin. Full article
(This article belongs to the Special Issue Element Enrichment and Gas Accumulation in Black Rock Series)
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23 pages, 11386 KiB  
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 463
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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18 pages, 5653 KiB  
Article
Effect of Dual-Site Co-Cultivation on Spectral Characteristics and Trace Element Enrichment in Akoya Pearls
by Peiqi Zhou, Geng Li and Fabian Schmitz
Minerals 2025, 15(6), 654; https://doi.org/10.3390/min15060654 - 18 Jun 2025
Viewed by 367
Abstract
This study systematically investigates for the first time the effects of dual-site co-cultivation on spectral characteristics and trace element enrichment in marine-cultured Akoya pearls from Beihai, China. Akoya pearls were cultured over a one-year period, with the final 40-day stage designated as the [...] Read more.
This study systematically investigates for the first time the effects of dual-site co-cultivation on spectral characteristics and trace element enrichment in marine-cultured Akoya pearls from Beihai, China. Akoya pearls were cultured over a one-year period, with the final 40-day stage designated as the terminal phase. During this period, two experimental groups of pearl oysters were established: Group Y remained in Beihai for continued local cultivation and harvest, while Group B was transferred to Weihai, Shandong Province, for terminal-stage farming under different thermal conditions. A series of comparative analyses were performed using Fourier-transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, Raman spectroscopy, X-ray fluorescence (XRF), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The FTIR results revealed distinct differences between the two groups in the distribution of amide and polysaccharide functional groups, particularly around 1643 cm−1 and 1100 cm−1. The UV-Vis spectra of Group B displayed characteristic absorption bands at 430 nm and 460 nm, associated with the organic matrix of the nacre. Raman spectroscopy further indicated a higher abundance of organic-related vibrational features in Group B. Additionally, both XRF and LA-ICP-MS analyses consistently showed significant differences in the concentrations and distributions of trace elements, particularly copper (Cu), cobalt (Co), and zinc (Zn). The findings demonstrate that the dual-site co-cultivation mode significantly impacts both the organic composition and trace element enrichment patterns in seawater Akoya pearls. This research provides valuable references for optimizing environmental parameters in pearl cultivation processes. Full article
(This article belongs to the Section Biomineralization and Biominerals)
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14 pages, 396 KiB  
Article
Financial and Technological Potential of Eco-Efficient Recycling of Waste Electronic Equipment
by Tomasz Suponik, Paweł Friebe, Umut Kar, Dawid M. Franke and Paulina Gołuch
Minerals 2025, 15(6), 653; https://doi.org/10.3390/min15060653 - 18 Jun 2025
Viewed by 341
Abstract
The paper presents the financial potential of recycling waste electronic equipment (WEE) in the form of printed circuit boards, hard drives, and lithium-ion batteries. Metal contents in selected types of WEE were presented, as well as their price and importance from an environmental, [...] Read more.
The paper presents the financial potential of recycling waste electronic equipment (WEE) in the form of printed circuit boards, hard drives, and lithium-ion batteries. Metal contents in selected types of WEE were presented, as well as their price and importance from an environmental, economic, and geopolitical perspective using indicators of relative supply risk and abiotic depletion potential (ADP). The potential benefits that recycling can bring to the company and the environment were presented. Furthermore, the mass balance and value of recovered metals were estimated for southern Poland, and potential possibilities for the management of the remaining separation products were presented. Finally, verified physical recycling methods for the presented WEE were described. Full article
(This article belongs to the Special Issue Mineral Processing and Recycling Technologies for Sustainable Future)
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17 pages, 7300 KiB  
Article
Mechanism of Iron Powder to Enhance Solid-State Reduction of Chromite Ore
by Xianghong Jiang, Feng Zhang, Yulong Cen and Zhuowei Lei
Minerals 2025, 15(6), 652; https://doi.org/10.3390/min15060652 - 17 Jun 2025
Viewed by 276
Abstract
This study investigated the solid-state reduction characteristics of natural chromite ore and the effect of iron powder on the solid-state reduction characteristics of natural chromite ore under isothermal conditions below 1200 °C. The enhancement mechanism of iron powder on the solid-state reduction of [...] Read more.
This study investigated the solid-state reduction characteristics of natural chromite ore and the effect of iron powder on the solid-state reduction characteristics of natural chromite ore under isothermal conditions below 1200 °C. The enhancement mechanism of iron powder on the solid-state reduction of natural chromite ore was revealed using optical microscopy, X-ray diffraction (XRD), and scanning electron microscopy–energy dispersive spectroscopy (SEM-EDS). The iron metallization rate of chromite ore exhibited a trend of increasing first and then decreasing with the addition of iron powder, and the optimal iron powder addition was determined to be 30%. The multi-step reaction gradually transforms into a single-step reaction with the increase in the dosage of iron powder. Iron powder facilitates the generation of a low-melting Fe-C alloy liquid phase and accelerates the speed of the solid-state reduction reaction of chromite ore and the disintegration of chromite spinel particles. When the iron powder dosage exceeds 30%, most of the multi-step reduction reaction of chromite ore is transformed into the single-step reduction reaction, which reduces the disintegration of chromite spinel particles and weakens the enhancement effect of iron powder on the solid-state reduction of chromite ore. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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25 pages, 9142 KiB  
Article
Petrogenesis and Tectonic Significance of Middle Jurassic Mafic–Ultramafic Cumulate Rocks in Weiyuanpu, Northern Liaoning, China: Insights from Zircon Geochronology and Isotope Geochemistry
by Yifan Zhang, Xu Ma, Jiafu Chen, Yuqi Liu, Yi Zhang and Yongwei Ma
Minerals 2025, 15(6), 651; https://doi.org/10.3390/min15060651 - 17 Jun 2025
Viewed by 403
Abstract
The tectonic evolution of the Paleo-Pacific Ocean and the destruction mechanism of the North China Craton (NCC) are still controversial. In this study, we conducted zircon U-Pb dating, whole-rock geochemistry, and Sr-Nd-Hf isotope analyses on the Weiyuanpu mafic–ultramafic intrusions in the eastern segment [...] Read more.
The tectonic evolution of the Paleo-Pacific Ocean and the destruction mechanism of the North China Craton (NCC) are still controversial. In this study, we conducted zircon U-Pb dating, whole-rock geochemistry, and Sr-Nd-Hf isotope analyses on the Weiyuanpu mafic–ultramafic intrusions in the eastern segment of the northern margin of the NCC to discuss their petrogenesis and tectonic implications. The Weiyuanpu mafic–ultramafic intrusions consist of troctolite, hornblendite, hornblende gabbro, gabbro, and minor diorite, anorthosite, characterized by cumulate structure. The main crystallization sequence of minerals is olivine → pyroxene → magnetite → hornblende. The zircon U-Pb ages of hornblendite, hornblende grabbro, and diorite are ~170Ma. Geochemical characteristics exhibit low-K tholeiitic to calc-alkaline series, enriched in light rare-earth elements (LREE) and significant large-ion lithophile elements (LILE), and depleted in high-field-strength elements (HFSE). Sr-Nd isotopic compositions are ISr = 0.7043–0.7055, εNd(t) = −0.7 to +0.9, and zircon εHf (t) values range from +3.4 to +8.7. These results suggest that the source region was a phlogopite-bearing garnet lherzolite mantle metasomatized by subduction fluids. The study reveals that the northeastern margin of the NCC was in a back-arc extensional setting due to the subduction of the Paleo-Pacific Ocean during the Middle Jurassic, which caused lithosphere thinning and mantle melting in this region. Full article
(This article belongs to the Special Issue Selected Papers from the 7th National Youth Geological Congress)
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20 pages, 5625 KiB  
Article
Pore Evolution Characteristics and Accumulation Effect of Lower Jurassic Continental Shale Gas Reservoirs in Northeastern Sichuan Basin
by Xinyi He, Tao Jiang, Zhenxue Jiang, Zhongbao Liu, Yuanhao Zhang and Dandan Wang
Minerals 2025, 15(6), 650; https://doi.org/10.3390/min15060650 - 16 Jun 2025
Viewed by 249
Abstract
The Sichuan Basin is a key area for shale gas energy exploration in China. However, the pore evolution mechanism and accumulation effect of the Lower Jurassic continental shale gas in the northeastern Sichuan Basin remain poorly understood. In this study, the pore structure [...] Read more.
The Sichuan Basin is a key area for shale gas energy exploration in China. However, the pore evolution mechanism and accumulation effect of the Lower Jurassic continental shale gas in the northeastern Sichuan Basin remain poorly understood. In this study, the pore structure characteristics of shale reservoirs and the dynamic accumulation and evolution of shale gas in the northern Fuling and Yuanba areas were systematically analyzed by adsorption experiments, high-pressure mercury injection joint measurement, and thermal simulation experiments. The results indicate the following: (1) The continental shale in the study area is predominantly composed of mesopores (10–50 nm), which account for approximately 55.21% of the total pore volume, followed by macropores (5–50 μm) contributing around 35.15%. Micropores exhibit the lowest proportion, typically less than 10%. Soluble minerals such as clay minerals and calcite significantly promote pore development, while soluble organic matter may block small pores during hydrocarbon generation, which facilitates the enrichment of free gas. (2) The thermal simulation experiment reveals that pore evolution can be divided into two distinct stages. Prior to 450 °C, hydrocarbon generation leads to a reduction in pore volume due to the compaction and transformation of organic matter. After 450 °C, organic matter undergoes cracking processes accompanied by the formation of shrinkage fractures, resulting in the development of new macropores and a significant increase in pore volume. This indicates that thermal energy input during the thermal evolution stage plays a key role in reservoir reconstruction. (3) The early Jurassic sedimentary environment controls the enrichment of organic matter, and the Cretaceous is the key period of hydrocarbon accumulation. Hydrocarbon generation and diagenesis synergistically promote the formation of gas reservoirs. The Cenozoic tectonic activity adjusted the distribution of gas reservoirs, and finally formed the enrichment model with the core of source–reservoir–preservation dynamic matching. For the first time, combined with dynamic thermal simulation experiments, this study clarifies the stage characteristics of pore evolution of continental shale and identifies the main controlling factors of shale gas accumulation in the Lower Jurassic in northeastern Sichuan, which provides a theoretical basis for continental shale gas exploration and energy resource development, offering important guidance for optimizing the selection of exploration target areas. Full article
(This article belongs to the Special Issue Distribution and Development of Faults and Fractures in Shales)
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20 pages, 3370 KiB  
Article
Reprocessing of Sulphide Flotation Tailings for Copper Recovery: Characterisation
by Richel Annan Dadzie, Massimiliano Zanin, William Skinner, Jonas Addai-Mensah, Richmond Asamoah and George Blankson Abaka-Wood
Minerals 2025, 15(6), 649; https://doi.org/10.3390/min15060649 - 16 Jun 2025
Viewed by 1042
Abstract
This study characterises low-grade copper ore tailings from a conventional flotation circuit to evaluate their feasibility for further processing. A suite of advanced analytical techniques, such as X-ray fluorescence (XRF), inductively coupled plasma (ICP), X-ray diffraction (XRD), and the quantitative evaluation of minerals [...] Read more.
This study characterises low-grade copper ore tailings from a conventional flotation circuit to evaluate their feasibility for further processing. A suite of advanced analytical techniques, such as X-ray fluorescence (XRF), inductively coupled plasma (ICP), X-ray diffraction (XRD), and the quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN), was employed to assess the elemental, chemical, and mineralogical composition of the tailings. Chalcopyrite was identified as the dominant copper-bearing mineral phase, predominantly locked within iron oxides and silicate gangue minerals. The QEMSCAN results showed that chalcopyrite was only partially liberated, which highlights the complex mineral intergrowths that hinder efficient recovery. Based on the mineralogical characteristics, the applicability of various processing techniques, including conventional froth flotation, advanced flotation methods [including HydrofloatTM, Jameson, and the Reflux Flotation Cell (RFC)], magnetic separation, and gravity separation, was evaluated. Overall, this study indicates that incorporating HydroFloat™, the Jameson Cell, and the RFC into the flotation circuit could greatly improve copper recovery from tailings. This study also identified rare earth elements (REEs) as potential by-products of copper recovery, so it is an additional opportunity for resource recovery. This paper contributes to sustainable mining practices and resource optimization by highlighting the characteristics and recovery of valuable minerals from tailings. Full article
(This article belongs to the Special Issue Sustainable Extraction and Reuse of Metallurgical Wastes: Towards Circular Practices)
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11 pages, 1410 KiB  
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 254
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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22 pages, 8030 KiB  
Article
Reservoir Characteristics and Hydrocarbon Potential of Cretaceous Volcanic Rocks in the Shimentan Formation, Xihu Sag, East China Sea Shelf Basin
by Yang Liu
Minerals 2025, 15(6), 647; https://doi.org/10.3390/min15060647 - 14 Jun 2025
Viewed by 315
Abstract
In recent years, significant exploration successes and research progress in volcanic hydrocarbon reservoirs across China’s offshore basins have highlighted their importance as key targets for deep hydrocarbon exploration. In the Shimentan Formation of the Xihu Sag, East China Sea Shelf Basin (ECSSB), low-yield [...] Read more.
In recent years, significant exploration successes and research progress in volcanic hydrocarbon reservoirs across China’s offshore basins have highlighted their importance as key targets for deep hydrocarbon exploration. In the Shimentan Formation of the Xihu Sag, East China Sea Shelf Basin (ECSSB), low-yield gas flows have been encountered through exploratory drilling; however, no major reservoir breakthroughs have yet been achieved. Assessing the large-scale reservoir potential of volcanic sequences in the Shimentan Formation is thus critical for guiding future exploration strategies. Based on previous exploration studies of volcanic reservoirs in other Chinese basins, this study systematically evaluates the hydrocarbon potential of these volcanic units by microscopic thin section identification, major element analysis, integrates drilling data with seismic interpretation techniques—such as coherence cube slicing for identifying volcanic conduits, dip angle analysis for classifying volcanic edifices, and waveform classification for delineating volcanic lithofacies. The main findings are as follows: (1) The Shimentan Formation is primarily composed of intermediate to acidic pyroclastic rocks and lava flows. Volcanic facies are divided into three facies, four subfacies, and six microfacies. Volcanic edifices are categorized into four types: stratified, pseudostratified, pseudostratified-massive, and massive. (2) Extensive pseudostratified volcanic edifices are developed in the Hangzhou Slope Zone, where simple and compound lava flows of effusive facies are widely distributed. (3) Comparative analysis with prolific volcanic reservoirs in the Songliao and Bohai Bay basins indicates that productive reservoirs are typically associated with simple or compound lava flows within pseudostratified edifices. Furthermore, widespread Late Cretaceous rhyolites in adjacent areas of the study region suggest promising potential for rhyolitic reservoir development in the Hangzhou Slope Zone. These results provide a robust geological foundation for Mesozoic volcanic reservoir exploration in the Xihu Sag and offer a methodological framework for evaluating reservoir potential in underexplored volcanic regions. Full article
(This article belongs to the Special Issue Petrology, Geochemistry, Geophysics, Modeling and Mapping of Volcanic/Igneous Reservoirs and Analog Volcanoes)
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15 pages, 5968 KiB  
Article
Production of Barium Sulfide from Low-Grade Barite Ores
by Mario Santander, Danny Guzmán, Marisela Navea, Luis Valderrama, Luis Pérez-Maqueda and Evelyn Cárdenas
Minerals 2025, 15(6), 646; https://doi.org/10.3390/min15060646 - 14 Jun 2025
Viewed by 384
Abstract
The manufacture of barium sulfide or barium salts (BaS, BaCl2, Ba (OH)2, among others) requires high-purity barite ores (>90%). In this study, a new method to produce barium sulfide from low-grade barite ores (60% purity) is proposed. The method [...] Read more.
The manufacture of barium sulfide or barium salts (BaS, BaCl2, Ba (OH)2, among others) requires high-purity barite ores (>90%). In this study, a new method to produce barium sulfide from low-grade barite ores (60% purity) is proposed. The method involves gravitational concentration of barite ore on a shaking table followed by mechanical activation of the barite concentrate with metallurgical coke in a ball mill. The mechanically activated mixture undergoes carbothermic reduction with an argon flow, resulting in the conversion of barite concentrate into barium sulfide. Gravitational concentration studies conducted using a shaking table demonstrated that, upon optimizing key operational parameters—namely, the wash-water flow rate, length, stroke frequency, the splitter positions of the concentrate, middlings, and tailings—a barite concentrate with a purity exceeding 95% BaSO4 was successfully achieved. Mechanical activation of the barite/coal mixture lowered the initial temperature of the carbothermic reduction from 1100 K to 990 K, enabling complete conversion of barite to BaS, as confirmed by thermogravimetric curves and XRD analysis. Furthermore, the activation energy during the carbothermic reduction ranged from 300 to 500 kJ/mol, suggesting a complex reduction process of barite with metallurgical coke that is difficult to represent by a single reaction. Full article
(This article belongs to the Topic New Advances in Mining Technology)
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16 pages, 3301 KiB  
Article
Crystal Chemistry and Thermodynamic Properties of Mineralogically Probable Phosphate Ca2.62Cu1.94Co1.44(PO4)4—Structurally Related to Natural Arsenate Zubkovaite
by Olga Yakubovich, Galina Kiriukhina, Larisa Shvanskaya and Alexander Vasiliev
Minerals 2025, 15(6), 645; https://doi.org/10.3390/min15060645 - 13 Jun 2025
Viewed by 314
Abstract
In this paper, we report the details of the synthesis, single crystal X-ray diffraction study, comparative crystal chemical analysis, and magnetic behavior of a new phosphate variation of the arsenate mineral zubkovaite. The title compound was obtained as a high-temperature flux product in [...] Read more.
In this paper, we report the details of the synthesis, single crystal X-ray diffraction study, comparative crystal chemical analysis, and magnetic behavior of a new phosphate variation of the arsenate mineral zubkovaite. The title compound was obtained as a high-temperature flux product in the form of a partly ordered solid solution and was studied using scanning electron microscopy and microprobe analysis. It possesses a monoclinic symmetry with a P21/n space group; the unit cell parameters are a = 8.8040 (2), b = 4.8970 (1), c = 14.5772 (3), and β = 93.993(2)°. The Ca2.62Cu1.94Co1.44(PO4)4 crystal structure exhibits some statistical disorder. Our refinement showed that two positions are mixed, being occupied by Cu/Co (M1) and Ca/Co (M2) atoms. Two types of layers that are nearly parallel to the (101) plane can be distinguished in the structure. One of them is built by sharing corners of CuO4 squares, M1O5 square pyramids, and PO4 tetrahedra. The second type of layer formed from Ca2+- and M2+-centered polyhedra alternates in the [1¯01] direction to construct a tri-periodic framework. Ca2.62Cu1.94Co1.44(PO4)4 experiences long-range antiferromagnetic ordering at low temperatures, as evidenced by both dc— and ac—magnetic susceptibilities, as well as by the specific heat measurements. Full article
(This article belongs to the Section Crystallography and Physical Chemistry of Minerals & Nanominerals)
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19 pages, 11500 KiB  
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 474
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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29 pages, 4559 KiB  
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 345
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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18 pages, 6276 KiB  
Article
Geochemical Survey of Stream Sediments and Stream Water for Ion-Adsorption Type Rare Earth Deposits (IAREDs): A Pilot Study in Jiaping IARED, Guangxi, South China
by Junhong Liu, Zhixuan Han, Chunfang Dong, Xiaocheng Wei and Yingnan Chen
Minerals 2025, 15(6), 642; https://doi.org/10.3390/min15060642 - 13 Jun 2025
Viewed by 406
Abstract
Rare earth elements (REEs) are critical mineral resources that play a pivotal role in modern technology and industry. Currently, the global supply of light rare earth elements (LREEs) remains adequate. However, the supply of heavy rare earth elements (HREEs) is associated with substantial [...] Read more.
Rare earth elements (REEs) are critical mineral resources that play a pivotal role in modern technology and industry. Currently, the global supply of light rare earth elements (LREEs) remains adequate. However, the supply of heavy rare earth elements (HREEs) is associated with substantial risks due to their limited availability. Ion-adsorption type rare earth deposits (IAREDs), which represent the predominant source of HREEs, have become a focal point for exploration activities, with a notable increase in global interest in recent years. This study systematically collected stream sediments and stream water samples from the Jiaping IARED in Guangxi, as well as from adjacent granitic and carbonate background areas, to investigate the exploration significance of geochemical surveys for IAREDs. Additionally, mineralized soil layers, non-mineralized soil layers, and bedrock samples from the weathering crust of the Jiaping deposit were analyzed. The results indicate that stream sediments originating from the Jiaping IARED and granite-hosted background regions display substantially elevated REE concentrations relative to those from carbonate-hosted background areas. Moreover, δEu values in stream sediments can serve as an effective indicator for differentiating weathering products derived from granitic and carbonate lithologies. Within the mining area, three coarse-grained fractions of stream sediments (i.e., +20 mesh, 20–60 mesh, and 60–150 mesh) exhibit REE concentrations comparable to those observed in both granite-hosted and carbonate-hosted background regions. However, the HREEs content in the finer -150-mesh stream sediments from Jiaping IARED is markedly higher than that in the two background regions. The (La/Sm)N versus (La/Yb)N ratios of -150-mesh stream sediments in the Jiaping IARED may reflect the mixing processes involving HREE-enriched ore layer, non-mineralized layer, and LREE-enriched ore layer. This observation implies that fine-grained (-150-mesh) stream sediments can partially inherit the REE characteristics of mineralized layers within IAREDs. Scanning electron microscopy (SEM) observations indicate that the enrichment of REEs in fine-grained stream sediments primarily originates from REE-rich accessory minerals derived from parent rocks and mineralized weathering crusts. A comparative analysis reveals that the concentrations of REEs in stream water collected during the rainy season are significantly higher than those collected during the dry season. Moreover, the levels of REEs, especially HREE, in stream water from the Jiaping IARED substantially exceed those in background areas. Collectively, these findings suggest that the geochemical signatures of REEs in rainy season stream water possess diagnostic potential for identifying IAREDs. In conclusion, the integrated application of geochemical surveys of stream water and -150-mesh stream sediments can effectively delineate exploration targets for IAREDs. Full article
(This article belongs to the Special Issue Novel Methods and Applications for Mineral Exploration, Volume III)
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24 pages, 20538 KiB  
Article
Data of Lithium from Triphylite LiFe2+PO4 Present in Conțu-Negovanu Pegmatites, in the Southern Carpathians, Romania
by Nicolae Călin, Ciprian Constantina, Diana Perșa, Valentina Cetean and Valentin Paraschiv
Minerals 2025, 15(6), 641; https://doi.org/10.3390/min15060641 - 12 Jun 2025
Viewed by 394
Abstract
This study aims to describe the triphylite (LiFe2+PO4) from Li-bearing pegmatites from the Conțu-Negovanu area (Southern Carpathians, Romania). Thus, for the first time in this area, using four analytical methods, i.e., electron micro-probe analysis (EMPA), polarized optical microscopy (POM), [...] Read more.
This study aims to describe the triphylite (LiFe2+PO4) from Li-bearing pegmatites from the Conțu-Negovanu area (Southern Carpathians, Romania). Thus, for the first time in this area, using four analytical methods, i.e., electron micro-probe analysis (EMPA), polarized optical microscopy (POM), Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (p-XRD), the authors have succeeded in isolating the triphylite from the isomorphous triphylite–lithiophilite series. In addition, in the Conțu-Negovanu area, two new minerals were identified and described for the first time in pegmatites from this area: Fe-rich gatehouseite and wolfeite. The use of EMPA allowed for the tentative calculation of empirical formulae for these secondary phosphate minerals. Full article
(This article belongs to the Special Issue Pegmatites as Hosts of Critical Metals: From Petrogenesis to Mineral Exploration)
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13 pages, 2746 KiB  
Article
A Cl-Dominant Analogue of Annite Occurs at the Eastern Edge of the Oktyabrsky Cu-Ni-PGE Deposit, Norilsk, Russia
by Andrei Y. Barkov, Giovanni Orazio Lepore, Luca Bindi, Robert F. Martin, Taras Panikorovskii, Ivan I. Nikulin and Sergey A. Silyanov
Minerals 2025, 15(6), 640; https://doi.org/10.3390/min15060640 - 12 Jun 2025
Viewed by 350
Abstract
A Cl-rich annitic mica is present in zones in taxitic gabbro–dolerite enriched in base metal sulfides in the eastern portion of the Oktyabrsky deposit in the Norilsk complex (Russia). Other Cl-enriched minerals in the assemblage include hastingsite (4.06 wt.% Cl), ferro-hornblende (2.53 wt.%), [...] Read more.
A Cl-rich annitic mica is present in zones in taxitic gabbro–dolerite enriched in base metal sulfides in the eastern portion of the Oktyabrsky deposit in the Norilsk complex (Russia). Other Cl-enriched minerals in the assemblage include hastingsite (4.06 wt.% Cl), ferro-hornblende (2.53 wt.%), and chlorapatite (>6 wt.%). New wavelength-dispersive electron probe analyses reveal compositions with up to 7.75 wt.% Cl, corresponding to the formula K0.742Na0.047Ca0.007)Σ0.796 (Fe2+2.901Mg0.078Mn0.047Ti0.007Cr0.003)Σ3.036 (Si3.190Al0.782)Σ3.972O10 (Cl1.105OH0.854F0.041)Σ2.000 based on 22 negative charges per formula unit, in which OH(calc.) = 2 − (Cl + F). Unfortunately, the grain size of the Cl-dominant mica precluded a single-crystal X-ray diffraction study even though its EBSD pattern confirms its identity as a member of the Mica group. We present results of a refinement of a crystal from the same mineralized sample containing 0.90(6) apfu Cl [R1 = 7.89% for 3720 unique reflections]. The mica is monoclinic, space group C2/m, a 5.3991(4), b 9.3586(6), c 10.2421(10) Å, β 100.873(9)°, V = 508.22(7) Å3, Z = 2. We also describe physical properties and provide a Raman spectrum. Among the mica compositions acquired from the same sample, a high Cl content is correlated with relative enrichment in Si, Mn, and Na and with a depletion in Al, Mg (low Mg#), K, Cr, and Ti. The buildup in Cl in the ore-forming environment is ultimately due to efficient fractional crystallization of the basic magma, with possible contributions from the Devonian metasedimentary sequences that it intruded. Full article
(This article belongs to the Collection New Minerals)
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33 pages, 48291 KiB  
Article
The Influence of Seasonal Variations in a Continental Lacustrine Basin in an Arid Climate on the Occurrence Characteristics of Gypsum: A Case Study from the Paleogene Bottom Sandstone Member, Tabei Uplift
by Xiaoyang Gao, Wenxiang He, Luxing Dou, Jingwen Yan, Qi Sun, Zhenli Yi and Bin Li
Minerals 2025, 15(6), 639; https://doi.org/10.3390/min15060639 - 12 Jun 2025
Viewed by 334
Abstract
The occurrence of gypsum in clastic rocks of continental saline lake basins reflects complex depositional and diagenetic processes. However, its genesis remains relatively understudied. Based on core descriptions and thin-section analyses, this study investigates the occurrence types and genetic mechanisms of gypsum in [...] Read more.
The occurrence of gypsum in clastic rocks of continental saline lake basins reflects complex depositional and diagenetic processes. However, its genesis remains relatively understudied. Based on core descriptions and thin-section analyses, this study investigates the occurrence types and genetic mechanisms of gypsum in the Bottom Sandstone Member of the northern Tabei Uplift. Five types of gypsum occurrences are identified: layered gypsum, gypsum clasts, spotted gypsum, gypsum nodules, and a mixed deposition of clastic rocks and gypsum. The mixed deposition of clastic rocks and gypsum includes gypsiferous mudstone, muddy gypsum, gypsiferous mudstone containing muddy clasts, and sandy gypsum. Layered gypsum, spotted gypsum, gypsiferous mudstone, and muddy gypsum mainly result from in situ chemical precipitation during periods of high evaporation and reduced runoff. In contrast, gypsum clasts, gypsiferous mudstone containing muddy clasts, and sandy gypsum reflect processes of transportation and reworking induced by flood events. Seasonal variations in hydrodynamic conditions play a critical role in the formation and distribution of gypsum. During dry periods, surface runoff weakens or ceases, and the salinity of lake water or pore water in clastic deposits increases due to intense evaporation, promoting gypsum precipitation. During flood periods, increased runoff can erode previously formed gypsum, which is subsequently transported and deposited as gypsum clasts. The morphology of gypsum varies with its transport distance. These findings enhance our understanding of clastic–evaporite mixed systems in arid continental lacustrine settings and provide insights into sedimentary processes influenced by seasonal climatic fluctuations. Full article
(This article belongs to the Special Issue Deep-Time Source-to-Sink in Continental Basins)
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36 pages, 5500 KiB  
Article
Metasomatic Mineral Systems with IOA, IOCG, and Affiliated Deposits: Ontology, Taxonomy, Lexicons, and Field Geology Data Collection Strategy
by Louise Corriveau, Jean-François Montreuil, Gabriel Huot-Vézina and Olivier Blein
Minerals 2025, 15(6), 638; https://doi.org/10.3390/min15060638 - 11 Jun 2025
Viewed by 387
Abstract
Metasomatic iron and alkali-calcic (MIAC) mineral systems form district-scale metasomatic footprints in the upper crust that are genetically associated with iron oxide–apatite (IOA), iron oxide and iron sulfide copper–gold (IOCG, ISCG), skarn, and affiliated critical and precious metal deposits. The development of MIAC [...] Read more.
Metasomatic iron and alkali-calcic (MIAC) mineral systems form district-scale metasomatic footprints in the upper crust that are genetically associated with iron oxide–apatite (IOA), iron oxide and iron sulfide copper–gold (IOCG, ISCG), skarn, and affiliated critical and precious metal deposits. The development of MIAC systems is characterized by series of alteration facies that form key mappable entities in the field and along drill cores. Each facies can precipitate deposit types specific to the facies or host deposits formed at a subsequent facies. Defining the spatial and temporal relations between alteration facies and host rocks as well as with pre, syn, and post MIAC magmatic, tectonic, and mineralization events is essential to understanding the evolution of a MIAC system and to evaluating its overall mineral prospectivity. This paper proposes an ontology for MIAC systems that frames the key characteristics of the main alteration facies described and links it to a taxonomy and descriptive lexicons that allow the user to build an efficient data collection system tailored to the description of MIAC systems. The application developed by the Geological Survey of Canada for collecting field data is used as an example. The data collection system, including the application for collecting field data and the lexicons, are applicable to regional- and deposit-scale geological mapping as well as to drill core logging. They respond to the need for the metallogenic mapping of mineral systems and the development of more robust mineral prospectivity maps and exploration strategies for the discovery of critical and precious metal resources in MIAC systems. Full article
(This article belongs to the Special Issue Footprints of Mineral Systems with IOCG, IOA and Affiliated Critical Metal Deposits: From Metasomatism to Metamorphism)
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19 pages, 3923 KiB  
Article
Palygorskite as an Extender Agent in Light Cement Pastes for Oil Wells: Performance Analysis
by Rafael A. Ventura, José V. A. Carvalho, Raphael R. da Silva, Francisco G. H. S. Pinto, Júlio C. O. Freitas and Sibele B. C. Pergher
Minerals 2025, 15(6), 637; https://doi.org/10.3390/min15060637 - 11 Jun 2025
Viewed by 373
Abstract
Cementing operations are among the most critical steps in oil-well construction. When performed improperly, the integrity and useful life of the well can be significantly compromised. Light cement pastes are used to cement formations with a low fracture gradient to ensure zonal isolation [...] Read more.
Cementing operations are among the most critical steps in oil-well construction. When performed improperly, the integrity and useful life of the well can be significantly compromised. Light cement pastes are used to cement formations with a low fracture gradient to ensure zonal isolation and maintain the integrity of the casing. Extenders are additives used to reduce the density of cement pastes, ensuring that the paste has desirable properties before and after setting. This work aimed to evaluate the application of palygorskite clay as an additive in lightweight cement pastes for oil wells, highlighting how its fibrous morphology influences the microstructure and enhances the macroscopic properties of the hardened cement matrix. For this, the clay sample was initially characterized regarding its physicochemical properties using X-ray diffraction (XRD), X-ray fluorescence (XRF), thermogravimetry (TG), textural analysis (BET/N2), and scanning electron microscopy (SEM). Lightweight pastes (1.56 g/cm3) were then formulated, varying the clay concentration by 1%, 3%, and 6% of the total mass. Cement pastes using bentonite were also formulated for comparison. Technological tests of atmospheric consistency, rheological behavior, free water, and stability were applied. It can be noted that the pastes formulated with palygorskite had lower viscosity, reflected in the reduced plastic viscosity and yield stress values, indicating easier flow behavior when compared with bentonite-based pastes. The pastes formulated with 6% palygorskite and 3% bentonite showed satisfactory stability and drawdown results. Therefore, applying palygorskite satisfies the minimum requirements for acting as an extending agent for lightweight cement pastes and is an option for application in oil-well cementing operations. 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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17 pages, 12181 KiB  
Article
Tectonic Evolution and Geological Significance of Jinchuan Region Along Northeastern Margin of Longshou Shan
by Zongyue Lu, Ruifeng Duan, Jiaqi Xu, Wei Zhang, Ke Yang, Dongxiang Jiang, Guoshuai Geng and Kang Sun
Minerals 2025, 15(6), 636; https://doi.org/10.3390/min15060636 - 11 Jun 2025
Viewed by 313
Abstract
The Jinchuan area is located along the northeastern margin of Longshou Shan, in the western part of the North China Plate. Since the Paleoproterozoic period, it has undergone complex geological evolution. A systematic analysis of the tectonic evolution in this region reveals key [...] Read more.
The Jinchuan area is located along the northeastern margin of Longshou Shan, in the western part of the North China Plate. Since the Paleoproterozoic period, it has undergone complex geological evolution. A systematic analysis of the tectonic evolution in this region reveals key information about the tectonic background and evolutionary characteristics since the Paleoproterozoic period and serves as a crucial approach for understanding metallogenic processes and achieving breakthroughs in deep mineral exploration. Based on detailed field investigations, this study analyzes the structural characteristics of the area, focusing on conjugate shear joints, folds, and faults. Combined with previous research findings, the evolution of the tectonic stress field is analyzed. The results indicate that the orientation of the maximum principal stress underwent the following six distinct phases of change: nearly north-south (NS) → nearly east-west (EW) → nearly north-south (NS) → north-northeast-south-southwest (NNE-SSW) → northwest-southeast (NW-SE) → northeast-southwest (NE-SW). Integrating these results with the regional tectonic framework, the study systematically reconstructs the tectonic evolution of the Jinchuan area. This research provides important scientific insights and practical value for enhancing geological understanding of the region and guiding mineral resource exploration and development. Full article
(This article belongs to the Section Mineral Exploration Methods and Applications)
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20 pages, 7353 KiB  
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Early Cretaceous Zn-Pb (Ba±Ag±Cu±Fe±Mn) Deposits of Iran: Irish Type or Mississippi Valley Type? Reply to Nejadhadad et al. Comment on “Rajabi et al. Barite Replacement as a Key Factor in the Genesis of Sediment-Hosted Zn-Pb±Ba and Barite-Sulfide Deposits: Ore Fluids and Isotope (S and Sr) Signatures from Sediment-Hosted Zn-Pb±Ba Deposits of Iran. Minerals 2024, 14, 671”
by Abdorrahman Rajabi, Pouria Mahmoodi, Pura Alfonso, Carles Canet, Colin J. Andrew, Reza Nozaem, Saeideh Azhdari, Somaye Rezaei, Zahra Alaminia, Somaye Tamarzadeh, Ali Yarmohammadi, Ghazaleh Khan Mohammadi, Negin Kourangi and Rasoul Saeidi
Minerals 2025, 15(6), 635; https://doi.org/10.3390/min15060635 - 11 Jun 2025
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Abstract
This study critically examines the early Cretaceous carbonate-hosted Zn-Pb (±Ba±Cu) deposits of the Malayer-Esfahan (MEMB) and Yazd-Anarak (YAMB) metallogenic belts in Iran, which have been inaccurately classified as Mississippi Valley type (MVT) deposits by Nejadhadad et al. (2025). Our findings reveal significant differences [...] Read more.
This study critically examines the early Cretaceous carbonate-hosted Zn-Pb (±Ba±Cu) deposits of the Malayer-Esfahan (MEMB) and Yazd-Anarak (YAMB) metallogenic belts in Iran, which have been inaccurately classified as Mississippi Valley type (MVT) deposits by Nejadhadad et al. (2025). Our findings reveal significant differences in mineralogy, fluid inclusion characteristics, and geochemical signatures compared to typical MVT deposits. These deposits are more akin to Irish-type Zn-Pb mineralization and formed in extensional and passive margin environments around the Nain–Baft back-arc basin. The normal faults in this back-arc rift can transform significantly during inversion and compressional tectonics, reactivating to behave as reverse faults and leading to new geological structures and landscapes. Our study highlights barite replacement as a crucial factor in forming sediment-hosted Zn-Pb (±Ba±Cu) and barite-sulfide deposits. Based on textural evidence, fluid inclusion data, and sulfur isotope analyses, we propose that barite plays a fundamental role in controlling subsequent Zn-Pb (±Ba±Cu) mineralization by serving as both a favorable host and a significant sulfur source. Furthermore, diagenetic barite may act as a precursor to diverse types of sediment-hosted Zn-Pb (±Ba±Cu) mineralization, refining genetic models for these deposits. Sulfur isotope analyses of Irish-type deposits show a broad δ34S range (−28‰ to +5‰), indicative of bacterial sulfate reduction (BSR). Nevertheless, more positive δ34S values (+1‰ to +36‰) and textural evidence in shale-hosted massive sulfide (SHMS) deposits suggest a greater role for thermochemical sulfate reduction (TSR) in sulfide mineralization. Full article
(This article belongs to the Special Issue Stratabound Barite Deposits: Mineralogy, Isotope Geochemistry and Geochronology)
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6 pages, 1786 KiB  
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Comment on Rajabi et al. Barite Replacement as a Key Factor in the Genesis of Sediment-Hosted Zn-Pb±Ba and Barite-Sulfide Deposits: Ore Fluids and Isotope (S and Sr) Signatures from Sediment-Hosted Zn-Pb±Ba Deposits of Iran. Minerals 2024, 14, 671
by Mostafa Nejadhadad, Batoul Taghipour and Somayeh Salamab Ellahi
Minerals 2025, 15(6), 634; https://doi.org/10.3390/min15060634 - 11 Jun 2025
Cited by 1 | Viewed by 294
Abstract
Rajabi et al. [...] Full article
(This article belongs to the Special Issue Stratabound Barite Deposits: Mineralogy, Isotope Geochemistry and Geochronology)
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