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12 pages, 1530 KiB  
Article
Effect of Aggregate Type on Asphalt–Aggregate Adhesion and Its Quantitative Characterization
by Liuxiao Chen, Junlin Li, Hao Xiang, Jun Zhang, Enlin Feng and Lin Kong
Materials 2025, 18(15), 3696; https://doi.org/10.3390/ma18153696 - 6 Aug 2025
Abstract
To study the effect of aggregate type on the adhesion between asphalt and aggregate, limestone, basalt, diabase, and 70# asphalt with SBS asphalt were selected. The mineral phase composition of the aggregates was analyzed by X-ray diffraction. The surface energy theory was used [...] Read more.
To study the effect of aggregate type on the adhesion between asphalt and aggregate, limestone, basalt, diabase, and 70# asphalt with SBS asphalt were selected. The mineral phase composition of the aggregates was analyzed by X-ray diffraction. The surface energy theory was used to calculate the adhesion work and the work of flaking. The modified water boiling method combined with image processing technology was used to quantitatively characterize the flaking behavior of the asphalt. The results show that the aggregate type is closely related to the asphalt–aggregate adhesion. The mineral compositions of different types of aggregates vary significantly, with limestone, being a strongly alkaline aggregate predominantly comprising CaCO3, exhibiting better adhesion with asphalt. The contact angle test and modified boiling method also yielded the same results, and the adhesion relationship with asphalt was limestone > basalt > diabase. Image processing technology effectively characterizes the spalling situation of asphalt and conducts quantitative analysis. Full article
(This article belongs to the Section Construction and Building Materials)
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21 pages, 19752 KiB  
Article
Phase Characterisation for Recycling of Shredded Waste Printed Circuit Boards
by Laurance Donnelly, Duncan Pirrie, Matthew Power and Andrew Menzies
Recycling 2025, 10(4), 157; https://doi.org/10.3390/recycling10040157 - 6 Aug 2025
Abstract
In this study, we adopt a geometallurgical analytical approach common in mineral processing in the characterization of samples of shredded waste printed circuit board (PCB) E-waste, originating from Europe. Conventionally, bulk chemical analysis provides a value for E-waste; however, chemical analysis alone does [...] Read more.
In this study, we adopt a geometallurgical analytical approach common in mineral processing in the characterization of samples of shredded waste printed circuit board (PCB) E-waste, originating from Europe. Conventionally, bulk chemical analysis provides a value for E-waste; however, chemical analysis alone does not provide information on the textural variability, phase complexity, grain size, particle morphology, phase liberation and associations. To address this, we have integrated analysis using binocular microscopy, manual scanning electron microscopy, phase, textural and compositional analyses by automated (SEM-EDS), phase analysis based on (Automated Material Identification and Classification System (AMICS) software, and elemental analysis using micro-XRF. All methods used have strengths and limitations, but an integration of these analytical tools allows the detailed characterization of the texture and composition of the E-waste feeds, ahead of waste reprocessing. These data can then be used to aid the design of optimized processing circuits for the recovery of the key payable components, and assist in the commercial trading of e-scrap. Full article
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22 pages, 9502 KiB  
Article
Phase-Field Modeling of Thermal Fracturing Mechanisms in Reservoir Rock Under High-Temperature Conditions
by Guo Tang, Dianbin Guo, Wei Zhong, Li Du, Xiang Mao and Man Li
Appl. Sci. 2025, 15(15), 8693; https://doi.org/10.3390/app15158693 (registering DOI) - 6 Aug 2025
Abstract
Thermal stimulation represents an effective method for enhancing reservoir permeability, thereby improving geothermal energy recovery in Enhanced Geothermal Systems (EGS). The phase-field method (PFM) has been widely adopted for its proven capability in modeling the fracture behavior of brittle solids. Consequently, a coupled [...] Read more.
Thermal stimulation represents an effective method for enhancing reservoir permeability, thereby improving geothermal energy recovery in Enhanced Geothermal Systems (EGS). The phase-field method (PFM) has been widely adopted for its proven capability in modeling the fracture behavior of brittle solids. Consequently, a coupled thermo-mechanical phase-field model (TM-PFM) was developed in COMSOL 6.2 Multiphysics to probe thermal fracturing mechanisms in reservoir rocks. The TM-PFM was validated against the analytical solutions for the temperature and stress fields under steady-state heat conduction in a thin-walled cylinder, three-point bending tests, and thermal shock tests. Subsequently, two distinct thermal fracturing modes in reservoir rock under high-temperature conditions were investigated: (i) fracture initiation driven by sharp temperature gradients during instantaneous thermal shocks, and (ii) crack propagation resulting from heterogeneous thermal expansion of constituent minerals. The proposed TM-PFM has been validated through systematic comparison between the simulation results and the corresponding experimental data, thereby demonstrating its capability to accurately simulate thermal fracturing. These findings provide mechanistic insights for optimizing geothermal energy extraction in EGS. Full article
(This article belongs to the Special Issue Advances in Failure Mechanism and Numerical Methods for Geomaterials)
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22 pages, 9028 KiB  
Article
Mechanochemical Activation of Basic Oxygen Furnace Slag: Insights into Particle Modification, Hydration Behavior, and Microstructural Development
by Maochun Xu, Liuchao Guo, Junshan Wen, Xiaodong Hu, Lei Wang and Liwu Mo
Materials 2025, 18(15), 3687; https://doi.org/10.3390/ma18153687 - 6 Aug 2025
Abstract
This study proposed a mechanochemical activation strategy using ethanol-diisopropanolamine (EDIPA) to improve the grindability and hydration reactivity of basic oxygen furnace slag (BOFS), aiming for its large-scale industrial utilization. The incorporation of EDIPA significantly refined the particle size distribution and reduced the repose [...] Read more.
This study proposed a mechanochemical activation strategy using ethanol-diisopropanolamine (EDIPA) to improve the grindability and hydration reactivity of basic oxygen furnace slag (BOFS), aiming for its large-scale industrial utilization. The incorporation of EDIPA significantly refined the particle size distribution and reduced the repose angle. As a result, the compressive strength of BOFS paste increased by 25.4 MPa at 28 d with only 0.08 wt.% EDIPA. Conductivity tests demonstrated that EDIPA strongly complexes with Ca2+, Al3+, and Fe3+, facilitating the dissolution of active mineral phases, such as C12A7 and C2F, and accelerating hydration reactions. XRD and TG analyses confirmed that the incorporation of EDIPA facilitated the formation of Mc (C4(A,F)ČH11) and increased the content of C-S-H, both of which contributed to microstructural densification. Microstructural observations further revealed that EDIPA refined Ca(OH)2 crystals, increasing their specific surface area from 4.7 m2/g to 35.2 m2/g. The combined effect of crystal refinement and enhanced hydration product formation resulted in reduced porosity and improved mechanical properties. Overall, the results demonstrated that EDIPA provided an economical, effective, and scalable means of activating BOFS, thereby promoting its high-value utilization in low-carbon construction materials. Full article
(This article belongs to the Special Issue Advances in Sustainable Construction Materials, Third Edition)
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13 pages, 266 KiB  
Article
Correlation Between Phase Angle and Body Composition, Strength and Nutritional Habits in Male Gamers
by Catarina N. Matias, Francesco Campa, Joana Cardoso, Margarida L. Cavaca, Rafael Carlos and Filipe J. Teixeira
Sports 2025, 13(8), 257; https://doi.org/10.3390/sports13080257 - 6 Aug 2025
Abstract
Gaming has evolved into a cultural phenomenon with a global reach, captivating millions of individuals. Nevertheless, little is known about this population. We aim to physiologically characterise the Portuguese gamers, bearing in mind that phase angle (PhA) is a general indicator of health, [...] Read more.
Gaming has evolved into a cultural phenomenon with a global reach, captivating millions of individuals. Nevertheless, little is known about this population. We aim to physiologically characterise the Portuguese gamers, bearing in mind that phase angle (PhA) is a general indicator of health, to check possible correlations between body composition, strength, and nutrition. A sample of 35 male gamers (individuals who play video games) was evaluated for anthropometry; body composition through DXA for whole-body bone mineral content (BMC), fat-free mass (FFM, kg), fat mass, and visceral adipose tissue, and through BIA (bioelectrical impedance analysis) for total body water (TBW), water pools (extracellular water and intracellular water, ICW), and PhA; strength through maximal isometric handgrip strength using a dynamometer; and nutritional intake using a three-day food record. Results show that participants are within reference metrics for all the analysed variables except regarding protein and carbohydrate intake (all values are above and below the Acceptable Macronutrient Distribution Ranges, respectively). A positive correlation was observed between PhA and TBW, ICW, handgrip strength, BMC and FFM, and a negative correlation with fat mass (absolute, percentage and visceral). In conclusion, PhA correlates with body composition variables, which aligns with previous research as a predictor of health and performance. Full article
11 pages, 225 KiB  
Article
Influence of Trace Mineral Sources and Levels on Growth Performance, Carcass Traits, Bone Characteristics, Oxidative Stress, and Immunity of Broiler
by Tassanee Trairatapiwan, Rachakris Lertpatarakomol, Sucheera Chotikatum, Achara Lukkananukool and Jamlong Mitchaothai
Animals 2025, 15(15), 2287; https://doi.org/10.3390/ani15152287 - 5 Aug 2025
Abstract
This study investigated the effects of reducing organic trace minerals below commercial inclusion levels and compared them with both low-dose and commercial levels of inorganic trace minerals, focusing on growth performance, carcass traits, tibia characteristics, oxidative stress (superoxide dismutase [SOD] and malondialdehyde [MDA]), [...] Read more.
This study investigated the effects of reducing organic trace minerals below commercial inclusion levels and compared them with both low-dose and commercial levels of inorganic trace minerals, focusing on growth performance, carcass traits, tibia characteristics, oxidative stress (superoxide dismutase [SOD] and malondialdehyde [MDA]), and immune response (serum IgG) in broilers. A total of 384 one-day-old Ross 308 chicks were randomly assigned to three dietary treatments: (1) commercial-level inorganic trace minerals (ILI; Zn 100 ppm; Cu 15 ppm; Fe 100 ppm; Mn 80 ppm; Se 0.2 ppm; I 3 ppm); (2) low-level organic trace minerals (LLO; Zn 30 ppm; Cu 4 ppm; Fe 11 ppm; Mn 30 ppm; Se 0.225 ppm; I 3 ppm), and (3) low-level inorganic trace minerals (LLI; Zn 30 ppm; Cu 4 ppm; Fe 11 ppm; Mn 30 ppm; Se 0.2 ppm; I 3 ppm). Each treatment consisted of eight replicates with 16 birds per replicate, and diets were provided in two phases: starter (days 1–21) and grower (days 22–35). The results showed that the LLO group demonstrated a significantly improved feed conversion ratio (FCR) during the starter phase, 2.4% better than that of the ILI and LLI groups (p = 0.02). Additionally, filet and thigh muscle yields in the LLO group were higher by 11.9% (p = 0.03) and 13.9% (p = 0.02), respectively, compared to the ILI group. Other carcass traits, as well as pH and drip loss, were not significantly affected. However, tibia breaking strength at day 35 was 15.1% lower in the LLO group compared to the ILI group (p = 0.02). No significant differences were observed in oxidative stress markers or IgG levels among groups. This study demonstrated that reducing the inclusion level of inorganic trace minerals did not negatively affect broiler growth performance, whereas supplementation with low levels of organic trace minerals improved both growth performance and carcass quality. Full article
(This article belongs to the Section Animal Nutrition)
20 pages, 4663 KiB  
Article
Investigation on Imbibition Recovery Characteristics in Jimusar Shale Oil and White Mineral Oil by NMR
by Dunqing Liu, Chengzhi Jia and Keji Chen
Energies 2025, 18(15), 4111; https://doi.org/10.3390/en18154111 - 2 Aug 2025
Viewed by 158
Abstract
Recovering oil by fracturing fluid imbibition has demonstrated significant potential for enhanced oil recovery (EOR) in tight oil reservoirs. White mineral oil (WMO), kerosene, or saturated alkanes with matched apparent viscosity have been widely used as “crude oil” to investigate imbibition mechanisms in [...] Read more.
Recovering oil by fracturing fluid imbibition has demonstrated significant potential for enhanced oil recovery (EOR) in tight oil reservoirs. White mineral oil (WMO), kerosene, or saturated alkanes with matched apparent viscosity have been widely used as “crude oil” to investigate imbibition mechanisms in light shale oil or tight oil. However, the representativeness of these simulated oils for low-maturity crude oils with higher viscosity and greater content of resins and asphaltenes requires further research. In this study, imbibition experiments were conducted and T2 and T1T2 nuclear magnetic resonance (NMR) spectra were adopted to investigate the oil recovery characteristics among resin–asphaltene-rich Jimusar shale oil and two WMOs. The overall imbibition recovery rates, pore scale recovery characteristics, mobility variations among oils with different occurrence states, as well as key factors influencing imbibition efficiency were analyzed. The results show the following: (1) WMO, kerosene, or alkanes with matched apparent viscosity may not comprehensively replicate the imbibition behavior of resin–asphaltene-rich crude oils. These simplified systems fail to capture the pore-scale occurrence characteristics of resins/asphaltenes, their influence on pore wettability alteration, and may consequently overestimate the intrinsic imbibition displacement efficiency in reservoir formations. (2) Surfactant optimization must holistically address the intrinsic coupling between interfacial tension reduction, wettability modification, and pore-scale crude oil mobilization mechanisms. The alteration of overall wettability exhibits higher priority over interfacial tension in governing displacement dynamics. (3) Imbibition displacement exhibits selective mobilization characteristics for oil phases in pores. Specifically, when the oil phase contains complex hydrocarbon components, lighter fractions in larger pores are preferentially mobilized; when the oil composition is homogeneous, oil in smaller pores is mobilized first. Full article
(This article belongs to the Special Issue New Progress in Unconventional Oil and Gas Development: 2nd Edition)
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17 pages, 14783 KiB  
Article
Behavior of Osteoblastic Lineage Cells When in the Presence of Tamoxifen: In Vitro and In Vivo Studies on Osseointegration
by Luiz Guilherme Fiorin, Emanuela Galliera, Henrique R. Matheus, Dolaji Henin, Edilson Ervolino, Gabriela Carrara Simionato, Juliano Milanezi de Almeida and Claudia Dellavia
Dent. J. 2025, 13(8), 351; https://doi.org/10.3390/dj13080351 - 1 Aug 2025
Viewed by 84
Abstract
Background/Objectives: Tamoxifen, a selective estrogen receptor modulator widely used as an adjunct in the treatment of breast cancer, has known effects on bone metabolism, although its impact on osseointegration and cellular responses during early bone healing remains unclear. Understanding these effects is essential [...] Read more.
Background/Objectives: Tamoxifen, a selective estrogen receptor modulator widely used as an adjunct in the treatment of breast cancer, has known effects on bone metabolism, although its impact on osseointegration and cellular responses during early bone healing remains unclear. Understanding these effects is essential given the increasing use of dental implants in cancer survivors. The study aimed to observe the influence of tamoxifen on human osteosarcoma (SAOS-2) cells lines, as well on the osseointegration of titanium implants in ovariectomized female rats. Methods: SAOS-2 cells were incubated with Dulbecco’s modified growth medium. Six titanium (Ti) disks were used at each time point. The samples were divided into groups with the presence (TAM, n = 36) or not (CTR, n = 36) of tamoxifen in a concentration of 2 μM. In vivo, 72 animals were divided in groups with bilateral ovariectomy or SHAM and tamoxifen administration or not (15 mg/kg). Cell viability, mineralization rate, and collagen synthesis were assessed, as well as bone/implant contact (BIC) and bone ingrowth (BIN). Results: Tamoxifen caused a decrease in SAOS-2 viability, although an increase in the mineralization rate was observed. In vivo, the TAM groups presented higher BIC and BIN when compared to their control, but a lower percentage of mature collagen cells. Conclusions: Based on our findings, in vitro, the therapy with TAM slightly reduced the viability of SAOS-2 cells while significantly increasing the mineralization rate. In vivo, the therapy positively influenced BIC and BIN during the osseointegration phase. Full article
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13 pages, 1750 KiB  
Article
Mineral-Based Synthesis of CuFe2O4 Nanoparticles via Co-Precipitation and Microwave Techniques Using Leached Copper Solutions from Mined Minerals
by Carolina Venegas Abarzúa, Mauricio J. Morel, Gabriela Sandoval-Hevia, Thangavel Kavinkumar, Natarajan Chidhambaram, Sathish Kumar Kamaraj, Nagarajan Dineshbabu and Arun Thirumurugan
Minerals 2025, 15(8), 819; https://doi.org/10.3390/min15080819 - 1 Aug 2025
Viewed by 139
Abstract
Environmental sustainability and responsible resource utilization are critical global challenges. In this work, we present a sustainable and circular-economy-based approach for synthesizing CuFe2O4 nanoparticles by directly utilizing copper oxide minerals sourced from Chilean mining operations. Copper sulfate (CuSO4) [...] Read more.
Environmental sustainability and responsible resource utilization are critical global challenges. In this work, we present a sustainable and circular-economy-based approach for synthesizing CuFe2O4 nanoparticles by directly utilizing copper oxide minerals sourced from Chilean mining operations. Copper sulfate (CuSO4) was extracted from these minerals through acid leaching and used as a precursor for nanoparticle synthesis via both chemical co-precipitation and microwave-assisted methods. The influence of different precipitating agents—NaOH, Na2CO3, and NaF—was systematically evaluated. XRD and FESEM analyses revealed that NaOH produced the most phase-pure and well-dispersed nanoparticles, while NaF resulted in secondary phase formation. The microwave-assisted method further improved particle uniformity and reduced agglomeration due to rapid and homogeneous heating. Electrochemical characterization was conducted to assess the suitability of the synthesized CuFe2O4 for supercapacitor applications. Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements confirmed pseudocapacitive behavior, with a specific capacitance of up to 1000 F/g at 2 A/g. These findings highlight the potential of CuFe2O4 as a low-cost, high-performance electrode material for energy storage. This study underscores the feasibility of converting primary mined minerals into functional nanomaterials while promoting sustainable mineral valorization. The approach can be extended to other critical metals and mineral residues, including tailings, supporting the broader goals of a circular economy and environmental remediation. Full article
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22 pages, 20436 KiB  
Article
An Adaptive Decomposition Method with Low Parameter Sensitivity for Non-Stationary Noise Suppression in Magnetotelluric Data
by Zhenyu Guo, Cheng Huang, Wen Jiang, Tao Hong and Jiangtao Han
Minerals 2025, 15(8), 808; https://doi.org/10.3390/min15080808 - 30 Jul 2025
Viewed by 125
Abstract
Magnetotelluric (MT) sounding is a crucial technique in mineral exploration. However, MT data are highly susceptible to various types of noise. Traditional data processing methods, which rely on the assumption of signal stationarity, often result in severe distortion when suppressing non-stationary noise. In [...] Read more.
Magnetotelluric (MT) sounding is a crucial technique in mineral exploration. However, MT data are highly susceptible to various types of noise. Traditional data processing methods, which rely on the assumption of signal stationarity, often result in severe distortion when suppressing non-stationary noise. In this study, we propose a novel, adaptive, and less parameter-dependent signal decomposition method for MT signal denoising, based on time–frequency domain analysis and the application of modal decomposition. The method uses Variational Mode Decomposition (VMD) to adaptively decompose the MT signal into several intrinsic mode functions (IMFs), obtaining the instantaneous time–frequency energy distribution of the signal. Subsequently, robust statistical methods are introduced to extract the independent components of each IMF, thereby identifying signal and noise components within the decomposition results. Synthetic data experiments show that our method accurately separates high-amplitude non-stationary interference. Furthermore, it maintains stable decomposition results under various parameter settings, exhibiting strong robustness and low parameter dependency. When applied to field MT data, the method effectively filters out non-stationary noise, leading to significant improvements in both apparent resistivity and phase curves, indicating its practical value in mineral exploration. Full article
(This article belongs to the Special Issue Novel Methods and Applications for Mineral Exploration, Volume III)
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17 pages, 2495 KiB  
Article
Production Capacity and Temperature–Pressure Variation Laws in Depressurization Exploitation of Unconsolidated Hydrate Reservoir in Shenhu Sea Area
by Yuanwei Sun, Yuanfang Cheng, Yanli Wang, Jian Zhao, Xian Shi, Xiaodong Dai and Fengxia Shi
Processes 2025, 13(8), 2418; https://doi.org/10.3390/pr13082418 - 30 Jul 2025
Viewed by 253
Abstract
The Shenhu sea area is rich in unconsolidated hydrate reserves, but the formation mineral particles are small, the rock cementation is weak, and the coupling mechanism of hydrate phase change, fluid seepage, and formation deformation is complex, resulting in unclear productivity change law [...] Read more.
The Shenhu sea area is rich in unconsolidated hydrate reserves, but the formation mineral particles are small, the rock cementation is weak, and the coupling mechanism of hydrate phase change, fluid seepage, and formation deformation is complex, resulting in unclear productivity change law under depressurization exploitation. Therefore, a thermal–fluid–solid–chemical coupling model for natural gas hydrate depressurization exploitation in the Shenhu sea area was constructed to analyze the variation law of reservoir parameters and productivity. The results show that within 0–30 days, rapid near-well pressure drop (13.83→9.8 MPa, 36.37%) drives peak gas production (25,000 m3/d) via hydrate dissociation, with porosity (0.41→0.52) and permeability (75→100 mD) increasing. Within 30–60 days, slower pressure decline (9.8→8.6 MPa, 12.24%) and fines migration cause permeability fluctuations (120→90 mD), reducing gas production to 20,000 m3/d. Within 60–120 days, pressure stabilizes (~7.6 MPa) with residual hydrate saturation < 0.1, leading to stable low permeability (60 mD) and gas production (15,000 m3/d), with cumulative production reaching 2.2 × 106 m3. This study clarifies that productivity is governed by coupled “pressure-driven dissociation–heat limitation–fines migration” mechanisms, providing key insights for optimizing depressurization strategies (e.g., timed heat supplementation, anti-clogging measures) to enhance commercial viability of unconsolidated hydrate reservoirs. Full article
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25 pages, 15689 KiB  
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 331
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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24 pages, 6356 KiB  
Article
The Significance of Metasomatism in the Formation of the Tanbreez REE Deposit in South Greenland
by Hans Kristian Schønwandt, Thomas Ulrich, Greg Barnes and Ole Christiansen
Minerals 2025, 15(8), 797; https://doi.org/10.3390/min15080797 - 29 Jul 2025
Viewed by 112
Abstract
The layering of the lower layered kakortokite in the per-alkaline Ilímaussaq complex has been interpreted as an orthocumulus rock. Petrographic observation and mineral chemical data from the topmost and the lowest part of the layered kakortokite show signs that indicate massive metasomatic overprint. [...] Read more.
The layering of the lower layered kakortokite in the per-alkaline Ilímaussaq complex has been interpreted as an orthocumulus rock. Petrographic observation and mineral chemical data from the topmost and the lowest part of the layered kakortokite show signs that indicate massive metasomatic overprint. The occurrence of globular structures in the top part of kakortokite and fine-grained inclusions in the lower layered kakortokite are interpreted as the precursor of kakortokite and the result of a subsolidus reaction between a fluid phase and the underlying rock, respectively. Two different processes led to the formation of kakortokite, a precursor where a clear repetitive layering occurs and a chemical reaction between a fluid phase and the underlying rock where different kakortokite types are randomly interstratified. Both metasomatic events led to a higher rare earth element (REE) grade of the original REE mineralization. Full article
(This article belongs to the Special Issue Ore Deposits Related to Metamorphism)
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39 pages, 8119 KiB  
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 324
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
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37 pages, 22971 KiB  
Article
Sedimentary Facies and Geochemical Signatures of the Khewra Sandstone: Reconstructing Cambrian Paleoclimates and Paleoweathering in the Salt Range, Pakistan
by Abdul Bari Qanit, Shahid Iqbal, Azharul Haq Kamran, Muhammad Idrees, Benjamin Sames and Michael Wagreich
Minerals 2025, 15(8), 789; https://doi.org/10.3390/min15080789 - 28 Jul 2025
Viewed by 1068
Abstract
Red sandstones of the Cambrian age are globally distributed and represent an important sedimentation phase during this critical time interval. Their sedimentology and geochemistry can provide key information about the sedimentation style, paleoclimatic conditions, and weathering trends during the Cambrian. In the Salt [...] Read more.
Red sandstones of the Cambrian age are globally distributed and represent an important sedimentation phase during this critical time interval. Their sedimentology and geochemistry can provide key information about the sedimentation style, paleoclimatic conditions, and weathering trends during the Cambrian. In the Salt Range of Pakistan, the Khewra Sandstone constitutes the Lower Cambrian strata and consists of red–maroon sandstones with minor siltstone and shale in the basal part. Cross-bedding, graded bedding, ripple marks, parallel laminations, load casts, ball and pillows, desiccation cracks, and bioturbation are the common sedimentary features of the formation. The sandstones are fine to medium to coarse-grained with subangular to subrounded morphology and display an overall coarsening upward trend. Petrographic analysis indicates that the sandstones are sub-arkose and sub-lithic arenites, and dolomite and calcite are common cementing materials. X-ray Diffraction (XRD) analysis indicates that the main minerals in the formation are quartz, feldspars, kaolinite, illite, mica, hematite, dolomite, and calcite. Geochemical analysis indicates that SiO2 is the major component at a range of 53.3 to 88% (averaging 70.4%), Al2O3 ranges from 3.1 to 19.2% (averaging 9.2%), CaO ranges from 0.4 to 25.3% (averaging 7.4%), K2O ranges from 1.2 to 7.4% (averaging 4.8%), MgO ranges from 0.2 to 7.4% (averaging 3.5%), and Na2O ranges from 0.1 to 0.9% (averaging 0.4%), respectively. The results of the combined proxies indicate that the sedimentation occurred in fluvial–deltaic settings under overall arid to semi-arid paleoclimatic conditions with poor to moderate chemical weathering. The Khewra Sandstone represents the red Cambrian sandstones on the NW Indian Plate margin of Gondwana and can be correlated with contemporaneous red sandstones in the USA, Europe, Africa, Iran, and Turkey (Türkiye). Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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