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Volume 14
Issue 9
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Minerals, Volume 14, Issue 9 (September 2024) – 110 articles

Cover Story (view full-size image): Bedded barite–sulfide deposits mined for barite rock near Aberfeldy, Scotland, are deformed and metamorphosed but retain textural, mineral–chemical, and isotopic (S,O) evidence for precipitation from hydrothermal fluids exhaled onto the Ediacaran seafloor. Localized conglomeratic textures suggest mechanical reworking of precipitated barite. The compositional diversity in pyrite and sphalerite reflects varied redox environments and proximity to hydrothermal discharges. Minor modifications occurred during diagenesis, including the growth of cross-cutting crystals of barite and gypsum. Encapsulated barium carbonates indicate early diagenetic barite dissolution with the incorporation of sulfur into pyrite, elevating pyrite δ34S. These deposits provide an example of the classic model of SEDEX mineralization. View this paper
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14 pages, 7636 KiB  
Article
Test Method for Mineral Spatial Distribution of BIF Ore by Imaging Spectrometer
by Wenhua Yi, Shanjun Liu, Ruibo Ding, Heng Yue, Haoran Wang and Jingli Wang
Minerals 2024, 14(9), 959; https://doi.org/10.3390/min14090959 - 23 Sep 2024
Viewed by 611
Abstract
The spatial distribution characteristics of iron ore components are important when measuring the difficulty of their beneficiation. Polarized light microscopy and scanning electron microscopy are traditional methods with some shortcomings, including complicated operation and low efficiency. Most of the laboratory hyperspectral imaging techniques [...] Read more.
The spatial distribution characteristics of iron ore components are important when measuring the difficulty of their beneficiation. Polarized light microscopy and scanning electron microscopy are traditional methods with some shortcomings, including complicated operation and low efficiency. Most of the laboratory hyperspectral imaging techniques that have emerged in recent years have been focused on the field of mineral resource exploration. In contrast, the mineral distribution and tectonic characteristics of iron ores have been relatively poorly studied in the field of beneficiation. To address the issue, 11 experimental samples of banded iron formation (BIF)-hosted iron ores were selected and tested using an imaging spectrometer. Then, based on the differences in spectral characteristic of the three main components (quartz, hematite, and magnetite) in the samples, the identification model of the spatial distribution of the iron ore components was established using the normalized spectral amplitude index (NSAI) and spectral angle mapper (SAM). The NSAI and SAM identify minerals based on spectral amplitude features and spectral morphological features of the sample, respectively. The spatial distribution of different minerals in the samples was tested using the model, and the test results demonstrated that the spatial distribution of the three components is consistent with the banded tectonic character of the sample. Upon comparison with the chemical test results, the mean absolute errors (MAE) of the model for quartz, hematite, and magnetite in the samples were 2.03%, 1.34%, and 1.55%, respectively, and the root mean square errors (RMSE) were 2.72%, 2.08%, and 1.85%, respectively, with the exception of one martite sample that reached an MAE of 10.17%. Therefore, the model demonstrates a high degree of accuracy. The research provides a new method to test the spatial distribution of iron ore components. Full article
(This article belongs to the Special Issue Mapping of Rocks and Minerals Using Hyperspectral Remote Sensing, 2nd Edition)
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17 pages, 10342 KiB  
Article
Characterization and Analysis of the Main Factors of Brittleness of Shale Oil Reservoirs in the Liushagang Formation, X Depression, Beibuwan Basin
by Fuqiang Lai, Yuejiao Liu, Mingzheng Tang, Chengxiang Zeng and Ruyue Wang
Minerals 2024, 14(9), 958; https://doi.org/10.3390/min14090958 - 23 Sep 2024
Viewed by 413
Abstract
The analysis of the main factors of brittleness is an important basis for the selection of engineering desserts in shale oil reservoirs. In this study, with the shale oil reservoir of the Liushagang Formation in the X Depression of the Beibuwan Basin as [...] Read more.
The analysis of the main factors of brittleness is an important basis for the selection of engineering desserts in shale oil reservoirs. In this study, with the shale oil reservoir of the Liushagang Formation in the X Depression of the Beibuwan Basin as the research object, a characterization and analysis of the main factors of brittleness of the reservoir was performed in order to further reveal the brittleness of shale reservoirs in the study area. The brittleness of reservoirs in the study area was controlled by both internal and external factors, and the main factors of brittleness in the target section included the maturity of organic matter, horizontal stress difference, and brittle minerals. As the maturity of organic matter increased, the density, elastic modulus, and hardness of casein increased and the differentially hardened internal structure occurred and significantly affected brittleness. The mineral composition of the reservoir was characterized by complex mineral types and high contents of brittle minerals, and the minerals determining brittleness were mainly quartz, feldspar, calcite, and dolomite. The horizontal stress difference of the shale oil section was relatively small and contributed to fracturing and reforming. This study clarified the brittleness characteristics of E2l shale and its main factors, and provided a basis for the selection of shale formation geo-engineering dessert layers in the study area. Full article
(This article belongs to the Special Issue Distribution and Development of Faults and Fractures in Shales)
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23 pages, 11481 KiB  
Article
Geological Controlling Factors on Mississippi Valley-Type Pb-Zn Mineralization in Western Semnan, Iran
by Soran Qaderi, Abbas Maghsoudi, Amin Beiranvand Pour and Mahyar Yousefi
Minerals 2024, 14(9), 957; https://doi.org/10.3390/min14090957 - 21 Sep 2024
Viewed by 547
Abstract
Mississippi Valley-type (MVT) Pb-Zn deposits are a subtype of sedimentary-hosted mineralization. These deposits are hosted by carbonate sequences in passive-margin tectonic settings. This paper uses the Fry technique and distance distribution analysis to model the spatial distribution pattern of MVT Pb-Zn deposits in [...] Read more.
Mississippi Valley-type (MVT) Pb-Zn deposits are a subtype of sedimentary-hosted mineralization. These deposits are hosted by carbonate sequences in passive-margin tectonic settings. This paper uses the Fry technique and distance distribution analysis to model the spatial distribution pattern of MVT Pb-Zn deposits in the west of Semnan province (Iran) and their association with some geological features, aiming at mapping mineral prospectivity in the area. The modeling results reveal that NE–SW trending faults and Permian-Cretaceous dolomites and limestone are, respectively, major structural and lithological controlling factors of mineralization that operate as conduits and physicochemical subsystems of ore formation. The integration of the corresponding evidence maps of the controlling factors with a model of the geochemical signature of MVT Pb-Zn deposits through a supervised random forest approach, a machine learning technique, gains an exceptional prospectivity map predicting 100% of the known MVT Pb-Zn deposits in only 15% of the study area, which is an achievement. The recognized targets can be planned for further exploration. Full article
(This article belongs to the Special Issue Mineralogy and Geochemistry of Polymetallic Ore Deposits)
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26 pages, 8922 KiB  
Article
Comparative Study of Sulfides from Porphyry, Skarn, and Carbonate-Replacement Mineralization at the Recsk Porphyry-Mineralized Complex, Hungary
by M�t� Bir�, Johann G. Raith, Monika Feichter, M�t� Hencz, Gabriella B. Kiss, Attila Vir�g and Ferenc Moln�r
Minerals 2024, 14(9), 956; https://doi.org/10.3390/min14090956 - 21 Sep 2024
Viewed by 492
Abstract
A calc–alkaline dioritic–andesitic–dacitic intrusive–volcanic complex of Early Oligocene (30 Ma) age and its Mesozoic sedimentary basement at Recsk host a well-preserved porphyry–skarn–polymetallic carbonate-replacement–epithermal mineral system. The unique occurrence offers an exceptional possibility to study these related mineralization types at a single locality. This [...] Read more.
A calc–alkaline dioritic–andesitic–dacitic intrusive–volcanic complex of Early Oligocene (30 Ma) age and its Mesozoic sedimentary basement at Recsk host a well-preserved porphyry–skarn–polymetallic carbonate-replacement–epithermal mineral system. The unique occurrence offers an exceptional possibility to study these related mineralization types at a single locality. This study presents the textural–paragenetic, compositional characteristics, and systematics of sulfide mineral assemblages for the porphyry, skarn, and carbonate-replacement ore types, which are currently situated at a depth of 500–1200 m below the present surface. Detailed petrography combined with EPMA analyses of molybdenite, galena, sphalerite, tetrahedrite-group minerals and Bi-bearing sulfosalts allows for the establishment of characteristic mineral and chemical fingerprints for each mineralization type. Rhenium concentration in molybdenite, occurring as rare disseminations and quartz–carbonate veinlets in altered host rocks in all three mineralization types, shows a decreasing trend towards the more distal mineralization types. High Re contents (x¯ = 1.04 wt.%, max. up to 4.47 wt%) are typical for molybdenite from the porphyry mineralization, but Re is not homogeneously distributed, neither within individual molybdenite crystals nor on a mineralization scale. Copper and Se show opposite behavior in molybdenite, both becoming enriched in the more distal mineralization types. Silver, Bi, and Se concentrations increase in galena and tetrahedrite-group minerals, both towards the country rocks, making them the best candidates for vectoring within the whole hydrothermal system. For tetrahedrite-group minerals, Ag, Bi, Se, together with Sb and Zn, are the suitable elements for fingerprinting; all these are significantly enriched in the distal carbonate-replacement mineralization compared to the other, more proximal ore types. Additionally, further trends can be traced within the composition of sulfosalts. Lead-bearing Bi sulfosalts preferentially occur in the polymetallic carbonate-replacement veins, while being under-represented in the skarn and porphyry mineralization. Porphyry mineralization hosts Cu-bearing Bi sulfosalts dominantly, while skarn is characterized by Bi-dominated sulfosalts. Sphalerite, although present in all mineralization types, cannot be used for fingerprinting, vectoring, or thermobarometry based on EPMA measurements only. Trace element contents of sphalerite are low, often below the detection limits of the analyses. This is further complicated by the intense “chalcopyrite disease” occurring throughout the distal mineralization types. All the above-listed major, minor, and trace element ore mineral characteristics enable the characterization of the Recsk ores by mineral geochemical fingerprints, providing a possible vectoring tool in porphyry Cu–(Mo)–Au-mineralized systems. Full article
(This article belongs to the Special Issue New Discovery and Exploration Methods of Porphyry and Epithermal Mineral Deposits)
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17 pages, 6853 KiB  
Article
New Ag-Rich Mn-Zn±Pb Vein Mineralization at the Mavro Xylo Manganese Oxide Deposit, Drama, Greece
by George Soulamidis, Christina Stouraiti, Panagiotis Voudouris and Harilaos Tsikos
Minerals 2024, 14(9), 955; https://doi.org/10.3390/min14090955 - 21 Sep 2024
Viewed by 493
Abstract
The manganese deposits at the Kato Nevrokopi area are located in the Drama Basin (Northern Greece) and belong to the Rhodope Metamorphic Province. The deposits were previously exploited for several supergene Mn-oxide ore bodies of massive, battery-grade nsutite, spatially associated with fault zones [...] Read more.
The manganese deposits at the Kato Nevrokopi area are located in the Drama Basin (Northern Greece) and belong to the Rhodope Metamorphic Province. The deposits were previously exploited for several supergene Mn-oxide ore bodies of massive, battery-grade nsutite, spatially associated with fault zones in the vicinity of Oligocene granitic intrusions. We conducted detailed geological, mineralogical, and geochemical investigations at the Mavro Xylo deposit, which led to the identification of Ag-rich Mn-Zn±Pb vein-type mineralization. The studied paragenesis appears to have developed during two hydrothermal stages: stage I, characterized by the mineral assemblage rhodonite–quartz–rhodochrosite–pyrophanite–pyrite–galena–Te bearing argentite–sphalerite–wurtzite–alabandite, and stage II, dominated by Ag-rich, Mn-Zn±Pb oxides in the form of fracture-fills along a high-angle NE-SW fault zone in brecciated marbles. Bulk analyses of the stage-II oxide assemblage yielded concentrations of Ag up to 0.57 wt.%. In the veins, wurtzite is present in bands, succeeded by manganese oxides, while calcite and quartz are the main gangue minerals. We placed particular emphasis on the occurrence of Ag in high concentrations within distinct manganese oxides. Major silver carriers include Zn-bearing todorokite, chalcophanite, and hydrous Pb-Mn oxide. The vein-type mineralization at Mavro Xylo shares many characteristics with other intermediate-sulfidation epithermal precious metal-rich deposits associated with high Mn concentrations. The evolution of the mineral paragenesis indicates a change in the physicochemical attributes of the ore-forming fluids, from initially reducing (stage I) to oxidizing (stage II). Although the origin of the initial ore-forming fluid remains to be constrained, the above redox change is tentatively attributed to the increasing incursion of meteoric waters over time. Full article
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27 pages, 5400 KiB  
Article
Lithology Identification Based on Improved Faster R-CNN
by Peng Fu and Jiyang Wang
Minerals 2024, 14(9), 954; https://doi.org/10.3390/min14090954 - 21 Sep 2024
Viewed by 568
Abstract
In the mining industry, lithological identification is crucial for ensuring the safety of equipment and personnel, as well as for improving production efficiency. Traditional ore identification methods, such as visual inspection, physical testing, and chemical analysis, have many limitations in terms of their [...] Read more.
In the mining industry, lithological identification is crucial for ensuring the safety of equipment and personnel, as well as for improving production efficiency. Traditional ore identification methods, such as visual inspection, physical testing, and chemical analysis, have many limitations in terms of their operational complexity and applicability. Modern ore identification technologies, especially those combined with deep learning methods, can effectively overcome these shortcomings and significantly enhance identification performance. However, mainstream deep learning object detection algorithms still face the issues of low accuracy and poor identification performance in challenging mining conditions. To handle these problems, an improved Faster R-CNN model is proposed in this study. Specifically, we replace the backbone network ResNet with Res2Net-50 and incorporate an improved Feature Pyramid Network (FPN) to enhance feature fusion, thereby further improving the model’s feature extraction capability. Region of Interest(ROI) Align replaces the ROI pooling layer to solve the spatial misalignment issue, providing a higher detection accuracy in tasks involving small object detection and precise boundary detection. Additionally, the backbone feature extraction network integrates an efficient channel attention (ECA) module to optimize high-resolution semantic information maps. By adding simulated noise, the model’s robustness and anti-interference capabilities are enhanced. Soft-NMS is used instead of traditional NMS, preserving more potential targets through a confidence decay mechanism, thereby improving the detection accuracy and robustness. The experimental results show that the improved Faster R-CNN model maintains efficient and accurate ore identification capabilities even in complex mining environments, demonstrating its great potential in practical applications. The model achieves significant improvements in detection accuracy and efficiency, providing strong support for the intelligent and automated identification of ores. Full article
(This article belongs to the Special Issue Application of Deep Learning and Computer Vision in Petrographic Images Analysis)
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20 pages, 6773 KiB  
Article
A Geochemical and Isotopic Investigation of Carbonatites from Huangshuian, Central China: Implications for Petrogenesis and Mantle Sources
by Hao Zhao, Antonio Simonetti, Stefanie Simonetti, Xiaopeng Cao and Yushan Du
Minerals 2024, 14(9), 953; https://doi.org/10.3390/min14090953 - 21 Sep 2024
Viewed by 599
Abstract
The exact geological processes involved in the formation of subduction zone-related carbonatites remain ambiguous, along with their implications for crustal/carbon recycling in carbonatite melt generation. This study provides new geochemical and stable (C, O) and radiogenic (Sr, Nd, Pb) isotope data for Huangshuian [...] Read more.
The exact geological processes involved in the formation of subduction zone-related carbonatites remain ambiguous, along with their implications for crustal/carbon recycling in carbonatite melt generation. This study provides new geochemical and stable (C, O) and radiogenic (Sr, Nd, Pb) isotope data for Huangshuian carbonatite, located within the Lesser Qinling Orogen, with the aim to decipher its complex petrogenetic history. The carbonatites display elevated CaO, low MgO and alkali contents, and significant enrichments of Pb, Mo, and HREEs compared to typical carbonatites. The δ13CPDB (−4.6 to −4.9‰) and δ18OSMOW (+6.6 to +7.8‰) values plot within the field of primary igneous carbonatites. The carbonatites are characterized by consistent radiogenic isotopic compositions [(87Sr/86Sr)i = 0.70599–0.70603; εNd = −10.4 to −12.8; 206Pb/204Pb =16.24–17.74]. These combined results suggest that the carbonatites represent late-stage differentiation products of a parental, mantle-derived carbonatite melt. Their corresponding Sr-Nd-Pb isotopic compositions support the hypothesis that the Lesser Qinling carbonatites originate from a heterogeneous upper mantle source involving an EMI-like mantle component coupled with minor assimilation of the basement rocks. The parental carbonatite melt was derived by the melting of carbonate-bearing subcontinental lithospheric mantle metasomatized as the result of Early Triassic subduction of the Mianlue Ocean. Full article
(This article belongs to the Special Issue Advances in Mantle–Crust Interactions for Petrogenesis and Ore-Forming Processes)
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17 pages, 3054 KiB  
Review
Advances and Prospects on Flotation Enhancement of Difficult-to-Float Coal by Emulsion: A Review
by Xin Wang, Huaigang Cheng and Danjing Ding
Minerals 2024, 14(9), 952; https://doi.org/10.3390/min14090952 - 20 Sep 2024
Viewed by 572
Abstract
Coal is expected to continue dominating the global energy landscape for a considerable period in the future. However, the depletion of high-quality coal resources and the increasing proportion of difficult-to-float coals are exacerbating environmental issues and leading to significant waste of carbon resources, [...] Read more.
Coal is expected to continue dominating the global energy landscape for a considerable period in the future. However, the depletion of high-quality coal resources and the increasing proportion of difficult-to-float coals are exacerbating environmental issues and leading to significant waste of carbon resources, making the clean and efficient utilization of such coals imperative. Enhancing the quality of coal through flotation is a prerequisite for the resource utilization of coal. Difficult-to-float coal, characterized by high hydrophilicity, complex pore structures, and fine particle size, poses challenges for efficient flotation using conventional collectors. Emulsions, owing to their exceptional surface and interfacial regulation capabilities and environmental adaptability, have been employed as flotation collectors for various minerals and have garnered significant attention in recent years for their application in the flotation of difficult-to-float coals. In the pursuit of green and cost-effective flotation technologies for such coals, this paper systematically reviews the causes of poor floatability in difficult-to-float coals and their latest research progress by emulsion flotation. It summarizes the impact of emulsion types and preparation methods on their properties and application areas, with a particular focus on the key mechanisms by which emulsion collectors enhance the flotation of difficult-to-float coals, including surface charge regulation, surface hydrophobicity modification, and interfacial tension control. Finally, this paper outlines future research directions on emulsion flotation, which will likely focus on the precise control of emulsion structure and size, the targeted separation of organic components by emulsion collectors under complex conditions, the development of low-cost and highly biocompatible synthetic reagents, and the development of efficient emulsion storage and transportation equipment. Full article
(This article belongs to the Special Issue Industrial Minerals Flotation—Fundamentals and Applications)
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14 pages, 6320 KiB  
Article
Fluidal Peperites Recorded in the Cretaceous Lacustrine Sediments in the Southern Korean Peninsula: Syn-Magmatic Sediment Fluidization and Its Influence on the Peperite Formation
by Min-Cheol Kim and Yong Sik Gihm
Minerals 2024, 14(9), 951; https://doi.org/10.3390/min14090951 - 20 Sep 2024
Viewed by 400
Abstract
This study assessed the influence of sediment and water redistribution in host sediments on peperite formation by examining the peperites at the boundary between Cretaceous lacustrine sedimentary successions and intruding dikes (D1 and D2). The peperite zones occur along the dike margins and [...] Read more.
This study assessed the influence of sediment and water redistribution in host sediments on peperite formation by examining the peperites at the boundary between Cretaceous lacustrine sedimentary successions and intruding dikes (D1 and D2). The peperite zones occur along the dike margins and consist of fluidal juvenile fragments, classified as Type A and Type B perperite zones based on lateral extent of the peperite zones. Type A peperite zone, the dominant type, exhibites a narrow distribution (<20 cm), whereas Type B peperite zone sporadically occurs along D1 with a wider width (<1 m). Type B peperite zone is laterally linked with clastic dikes. These dikes containi fluidal shaped dike fragments with jigsaw-fit textures, indicating syn-magmatic fluidization and the resultant formation of the clastic dike via heat transfer. During dike emplacement, the interaction between the host sediments and the intruding magma formed Type A along the margins. Simultaneously, the clastic dikes, composed of fluidized sediments and water, supplied additional water and sediments, enhancing magma-host sediment intermingling and leading to the wide lateral extent of Type B. Our findings demonstrate that sediment and water redistribution via syn-magmatic fluidization is crucial in peperite formation, influencing the initial processes of phreatomagmatic volcanism. Full article
(This article belongs to the Special Issue Sedimentary Basins: Sedimentation, Stratigraphy, Petrology and Tectonics)
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15 pages, 19399 KiB  
Article
Fast Elemental Analysis of Heavy Mineral Suites by Scanning Electron Microscopy (SEM-Unity BEX)
by Jim Buckman, Amy Gough and Max Webb
Minerals 2024, 14(9), 950; https://doi.org/10.3390/min14090950 - 19 Sep 2024
Viewed by 721
Abstract
Developments in scanning electron microscopy (SEM) have introduced instant live coloured SEM images based on elemental composition. Here, we use a technique utilising a Unity BEX detector system, with collection speeds up to 100 times faster than typical standard energy-dispersive X-ray (EDX) analysis [...] Read more.
Developments in scanning electron microscopy (SEM) have introduced instant live coloured SEM images based on elemental composition. Here, we use a technique utilising a Unity BEX detector system, with collection speeds up to 100 times faster than typical standard energy-dispersive X-ray (EDX) analysis systems, to obtain large area backscattered and elemental composition maps of heavy mineral (HM) suites from a sample from an Oligocene fluvio-deltaic system in the Central Myanmar Basin. The fast X-ray collection rate and a high-resolution backscattered (BSE) detector allow for rapid imaging of polished blocks, thin sections, and stubs. Individual HM species can be rapidly classified, allowing for the subsequent collection of compositional and morphological metrics. In addition, the identification of grains such as zircon and apatite allow for further analysis by cathodoluminescence (CL) to identify and record the presence of growth zonation, which is critical for further U-Pb geochronology and thermochronology, using fission track analysis of apatite, zircon, and titanite. The sample used in this study contains a diverse heavy mineral suite due to the complex tectonic history of Myanmar, juxtaposing multiple metamorphic basement terranes alongside volcanic arcs and obducted ophiolites. This, along with the textural and mineralogical immaturity of the sediments themselves (governed by short transport systems and the rapid weathering of the sources), means that a wide variety of heavy mineral species can be identified and tested using this new technique, which provides a time-efficient method in comparison to traditional optical techniques. As the Unity BEX detector is located at the polepiece, it is relatively insensitive to working distance; in addition, the geometry of paired X-ray detectors on either side of the polepiece (at 180°) means that the system is also capable of fully characterising individual particles, on uncut and unpolished grain mounts, without artefacts such as particle shadowing. The development of a more comprehensive heavy mineral EDX database (library) will improve the accuracy of this new technique, as will the correlation with other techniques such as Raman spectroscopy. Full article
(This article belongs to the Special Issue Mineralogical and Geochemical Characterization of Geological Materials)
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30 pages, 19679 KiB  
Article
Paleoenvironmental Transition during the Rhuddanian–Aeronian and Its Implications for Lithofacies Evolution and Shale Gas Exploration: Insights from the Changning Area, Southern Sichuan Basin, South-West China
by Hangyi Zhu
Minerals 2024, 14(9), 949; https://doi.org/10.3390/min14090949 - 18 Sep 2024
Viewed by 457
Abstract
During the Rhuddanian–Aeronian interglacial period, global geological events such as glacial melting, synsedimentary volcanic activity, biological resurgence, and large-scale marine transgressions caused frequent fluctuations in paleoproductivity, climate changes, and sea level variations. These paleoenvironmental transitions directly influenced the development characteristics of shale lithofacies. [...] Read more.
During the Rhuddanian–Aeronian interglacial period, global geological events such as glacial melting, synsedimentary volcanic activity, biological resurgence, and large-scale marine transgressions caused frequent fluctuations in paleoproductivity, climate changes, and sea level variations. These paleoenvironmental transitions directly influenced the development characteristics of shale lithofacies. This study investigates the Longmaxi Formation shale in the Changning area in the Southern Sichuan basin, focusing on 28 core samples from Well N1. Using scanning electron microscopy, QEMSCAN, TOC, XRD, and major and trace element analyses, we reconstructed the paleoenvironmental transitions of this period and explored their control over shale lithofacies types and mineral compositions. Four shale lithofacies were identified: carbonate rich lithofacies (CRF), biogenic quartz-rich lithofacies (BQRF), detrital clay-rich lithofacies (CRDF), and detrital quartz-rich lithofacies (DQRF). During the Rhuddanian period, rising global temperatures caused glacial melting and rapid marine transgressions. The low oxygen levels in bottom waters, combined with upwelling and abundant volcanic material, led to high paleoproductivity. This period primarily developed BQRF and CRF. Rich nutrients and abundant siliceous organisms, along with anoxic to anaerobic conditions, provided the material basis and preservation conditions for high biogenic quartz and organic matter content. High paleoproductivity and anoxic conditions also facilitated the precipitation of synsedimentary calcite and supplied Mg2+ and SO42− for the formation of iron-poor dolomite via sulfate reduction. From the Late Rhuddanian to the Mid-Aeronian, the Guangxi orogeny caused sea levels to fall, increasing water oxidation and reducing upwelling and volcanic activity, which lowered paleoproductivity. Rapid sedimentation rates, stepwise global temperature increases, and the intermittent intensification of weathering affected terrigenous clastic input, resulting in the alternating deposition of CRF, CRDF, and DQRF. Two favorable shale gas reservoirs were identified from the Rhuddanian–Aeronian period: Type I (BQRF) in the L1–L3 Layers, characterized by high TOC and brittleness, and Type II (DQRF) in the L4 Layer, with significant detrital quartz content. The Type I-favorable reservoir supports ongoing gas production, and the Type II-favorable reservoir offers potential as a future exploration target. Full article
(This article belongs to the Special Issue Environment and Geochemistry of Sediments, 2nd Edition)
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24 pages, 8983 KiB  
Article
Microseismic Monitoring and Disaster Warning via Mining and Filling Processes of Residual Hazardous Ore Bodies
by Zilong Zhou, Yinghua Huang and Congcong Zhao
Minerals 2024, 14(9), 948; https://doi.org/10.3390/min14090948 - 18 Sep 2024
Viewed by 448
Abstract
The thick ore bodies in the Xianglushan tungsten mine have been irregularly mined, forming a super large, connected irregular goaf group and tall, isolated irregular pillars inside. At the same time, there is a production capacity task of recovering residual and dangerous ore [...] Read more.
The thick ore bodies in the Xianglushan tungsten mine have been irregularly mined, forming a super large, connected irregular goaf group and tall, isolated irregular pillars inside. At the same time, there is a production capacity task of recovering residual and dangerous ore bodies. This poses the potential for serious ground-pressure disasters, such as roof caving, pillar collapse, and large-scale goaf collapse during mining. Based on the actual needs of the site, we established a microseismic monitoring system. After analyzing the mining and filling processes and their relationships, and, combined with the distribution characteristics of microseismic multiple parameters, we constructed a ground-pressure disaster warning mode and mechanism. We analyzed the stability of the goaf, further formed a warning system, and achieved disaster warning. In response to the current situation of the difficulty of early warning of ground pressure in the Xianglushan tungsten mine, continuous on-site monitoring of existing goaves, point pillars, and strip pillars, as well as analysis of stress changes during dynamic mining and filling processes, we explored scientific and reasonable early warning mechanisms and models, understanding the relationship between the changes in microseismic parameters during dynamic mining and filling processes and ground pressure, studying and improving the reliability of underground microseismic monitoring and early warning, and achieved the internal connection between building early warning systems and the prevention of ground-pressure disasters. The results indicate that the mining and filling process of the ore body is the main factor in maintaining a stable and balanced distribution of underground ground pressure in mining engineering. Microseismic monitoring can invert the evolution of ground pressure and form a feedback system with ground-pressure warning, achieving mine safety management. Full article
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23 pages, 1759 KiB  
Article
Characterization of Humic Acid Salts and Their Use for CO2 Reduction
by Tomasz Spietz, Maira Kazankapova, Szymon Dobras, Zhanar Kassenova, Bolat Yermagambet, Andrey Y. Khalimon and Sławomir Stelmach
Minerals 2024, 14(9), 947; https://doi.org/10.3390/min14090947 - 18 Sep 2024
Viewed by 752
Abstract
The European Union aims to be climate neutral by 2050. To achieve this ambitious goal, net greenhouse gas emissions must be reduced by at least 55% by 2030. Post-combustion CO2 capture methods are essential to reduce CO2 emissions from the chemical [...] Read more.
The European Union aims to be climate neutral by 2050. To achieve this ambitious goal, net greenhouse gas emissions must be reduced by at least 55% by 2030. Post-combustion CO2 capture methods are essential to reduce CO2 emissions from the chemical industry, power generation, and cement plants. To reduce CO2, it must be captured and then stored underground or converted into other valuable products. Apromising alternative for CO2 reduction is the use of humic acid salts (HASs). This work describes a process for the preparation of potassium (HmK) and ammonium (HmA) humic acid salts from oxidized lignite (leonardite). A detailed characterization of the obtained HASs was conducted, including elemental, granulometric, and thermogravimetric analyses, as well as 1H-NMR and IR spectroscopy. Moreover, the CO2 absorption capacity and absorption rate of HASs were experimentally investigated. The results showed that the absorption capacity of the HASs was up to 10.9 g CO2 per kg. The CO2 absorption rate of 30% HmA solution was found to be similar to that of 30% MEA. Additionally, HmA solution demonstrated better efficiency in CO2 absorption than HmK. One of the issues observed during the CO2 absorption was foaming of the solutions, which was more noticeable with HmK. Full article
(This article belongs to the Special Issue Carbon Dioxide Storage, Utilization & Reduction)
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21 pages, 10207 KiB  
Article
Hydrothermal Karstification of the Pre-Messinian Eonile Canyon: Geomorphological and Geochemical Evidences for Hypogene Speleogenesis in the Middle Nile Valley of Egypt
by Ashraf A. Mostafa, Hatem M. El-Desoky, Diaa A. Saadawi, Ahmed M. Abdel-Rahman, John Webb, Hassan Alzahrani, Fahad Alshehri, Abdurraouf Okok, Ahmed E. Khalil and Eman A. Marghani
Minerals 2024, 14(9), 946; https://doi.org/10.3390/min14090946 - 16 Sep 2024
Viewed by 801
Abstract
The surface and subsurface karst features of the Eocene limestone plateaus along the Middle Nile Valley in Egypt were formerly believed to be epigene in origin and to have developed during post-Eocene pluvial periods. However, the morphology of the caves and their restriction [...] Read more.
The surface and subsurface karst features of the Eocene limestone plateaus along the Middle Nile Valley in Egypt were formerly believed to be epigene in origin and to have developed during post-Eocene pluvial periods. However, the morphology of the caves and their restriction to particular stratigraphic intervals suggests that they are hypogene. The geochemistry and mineralogy of the soft, thick-bedded, brown/black cave infills shows that these sediments originated from hydrothermal processes, as evidenced by their Fe, Mn, Co, Ni, and Cu concentrations. Thus, the karst features are hypogene and probably formed during the opening of the Red Sea Rift at the end of the Oligocene and early Miocene. At this time, there was abundant volcanic activity, as shown by basalt lavas ~70 km northwest of Assiut; this triggered the release of large amounts of CO2 that made the hydrothermal waters acidic and dissolved the caves. Full article
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22 pages, 12515 KiB  
Article
Application of Machine Learning to Characterize Metallogenic Potential Based on Trace Elements of Zircon: A Case Study of the Tethyan Domain
by Jin Guo and Wen-Yan He
Minerals 2024, 14(9), 945; https://doi.org/10.3390/min14090945 - 16 Sep 2024
Viewed by 657
Abstract
Amidst the rapid advancement of artificial intelligence and information technology, the emergence of big data and machine learning provides a new research paradigm for mineral exploration. Focusing on the Tethyan metallogenic domain, this paper conducted a series of research works based on machine [...] Read more.
Amidst the rapid advancement of artificial intelligence and information technology, the emergence of big data and machine learning provides a new research paradigm for mineral exploration. Focusing on the Tethyan metallogenic domain, this paper conducted a series of research works based on machine learning methods to explore the critical geochemical element signals that affect the metallogenic potential of porphyry deposits and reveal the metallogenic regularity. Binary classifiers based on random forest, XGBoost, and deep neural network are established to distinguish zircon fertility, and these machine learning methods achieve higher accuracy, exceeding 90%, compared with the traditional geochemical methods. Based on the random forest and SHapley Additive exPlanations (SHAP) algorithms, key chemical element characteristics conducive to magmatic mineralization are revealed. In addition, a deposit classification model was constructed, and the t-SNE method was used to visualize the differences in zircon trace element characteristics between porphyry deposits of different mineralization types. The study highlights the promise of machine learning algorithms in metallogenic potential assessment and mineral exploration by comparing them with traditional chemical methods, providing insights into future mineral classification models utilizing sub-mineral geochemical data. Full article
(This article belongs to the Special Issue The Formation and Evolution of Gold Deposits in China)
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14 pages, 3804 KiB  
Article
Study on the Effects of Microwave Heating Time and Power on the Mechanical Properties of Cemented Tailings Backfill
by Pengchu Ding, Shiheng Yan, Qinqiang Guo, Liwu Chang, Zhen Li, Changtai Zhou, Dong Han and Jie Yang
Minerals 2024, 14(9), 944; https://doi.org/10.3390/min14090944 - 15 Sep 2024
Viewed by 605
Abstract
With the escalating demand for advanced and eco-friendly processing technologies in mining engineering, the potential applications of microwave heating technology in the treatment of cement tailings backfill (CTB) are expanding significantly. This research comprehensively investigates the mechanisms through which microwave irradiation duration and [...] Read more.
With the escalating demand for advanced and eco-friendly processing technologies in mining engineering, the potential applications of microwave heating technology in the treatment of cement tailings backfill (CTB) are expanding significantly. This research comprehensively investigates the mechanisms through which microwave irradiation duration and power influence the mechanical properties of CTB with varying concentrations and cement-to-sand ratios. The aim is to reveal the influencing patterns through experimental methods, providing scientific evidence for optimizing CTB treatment processes. This paper conducted microwave heating tests, uniaxial compression tests, and SEM-EDS tests on CTB. The research results indicate that heating time and power significantly enhance the early strength of CTB, with a more pronounced effect on CTB with higher concentrations and higher cement–sand ratios. When the heating time is 7 min and the heating power is 340 W, the cement hydration reaction is maximally promoted, thereby increasing the density and strength growth rate of CTB. However, excessively long heating time or overly high heating power may cause microcracks or thermal stress concentration within the CTB, adversely affecting the strength growth rate of CTB. Optimal thermal exposure duration and microwave power settings facilitate the activation of cementitious materials and the nucleation of calcium-silicate-hydrate (C-S-H) phases, thereby accelerating the compressive strength evolution of cemented tailings backfill (CTB). The outcomes of this research offer valuable insights into the deployment of microwave heating methodologies in underground mine backfilling, which are pivotal for augmenting the economic viability and environmental sustainability of mining operations. Full article
(This article belongs to the Topic New Advances in Mining Technology)
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31 pages, 4027 KiB  
Review
Toward Viable Industrial Solid Residual Waste Recycling: A Review of Its Innovative Applications and Future Perspectives
by Tugba Keskin, Erol Yilmaz, Tugrul Kasap, Muhammet Sari and Shuai Cao
Minerals 2024, 14(9), 943; https://doi.org/10.3390/min14090943 - 15 Sep 2024
Viewed by 1891
Abstract
Industrial solid residual waste (ISRW) generated during and/or due to the making of energy, heat, and raw materials poses a major threat to a sustainable future due to its large production quantities and complex characteristics. Especially improper disposal of ISRW (e.g., coal ashes, [...] Read more.
Industrial solid residual waste (ISRW) generated during and/or due to the making of energy, heat, and raw materials poses a major threat to a sustainable future due to its large production quantities and complex characteristics. Especially improper disposal of ISRW (e.g., coal ashes, municipal waste residue, and biomass ashes) not only threatens human health but can also cause environmental hazards such as water, soil, and air pollution, upsetting the global balance. Given the environmental impacts as well as increasingly stringent disposal regulations, lack of landfills, and economic constraints, more sustainable and naturally friendly management strategies are being adopted for ISRW. While numerous studies in the literature have considered various characteristics of ISRW, a complete appraisal of the entire practice, from making to disposal, is still lacking. This paper presents an overview of the making, features, and traditional and innovative managing tactics of ISRW within the context of a general legal framework. This paper provides a scientific review of the various production types, global production quantities, and characteristics of ISRW. Additionally, the orthodox management strategies of ISRWs are scrutinized from a sociological and ecological standpoint, and diverse techniques for more viable and secure management are elucidated. This review culminates in an examination of the global impact and advantages of ISRW management policies based on legislation and regulations. Consequently, this paper seeks to elucidate the extant practices and a few recent advancements pertaining to ISRWs. Additionally, it underscores the ecological, sociological, and economic issues engendered by ISRWs and proposes innovative applications and production technologies. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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17 pages, 6340 KiB  
Article
Shale Oil Generation Conditions and Exploration Prospects of the Cretaceous Nenjiang Formation in the Changling Depression, Songliao Basin, China
by Wenjun Zhang, Wenyu Zhang, Shumin Lin, Xing Ke, Min Zhang and Taohua He
Minerals 2024, 14(9), 942; https://doi.org/10.3390/min14090942 - 15 Sep 2024
Viewed by 484
Abstract
Low-maturity shale oil predominates in shale oil resources. China’s onshore shale oil, particularly the Cretaceous Nenjiang Formation in the Songliao Basin, holds significant potential for low-maturity shale oil, presenting promising exploration and development prospects. This study delves into the hydrocarbon generation conditions, reservoir [...] Read more.
Low-maturity shale oil predominates in shale oil resources. China’s onshore shale oil, particularly the Cretaceous Nenjiang Formation in the Songliao Basin, holds significant potential for low-maturity shale oil, presenting promising exploration and development prospects. This study delves into the hydrocarbon generation conditions, reservoir characteristics, and oil-bearing property analysis of the mud shale from the Nen-1 and Nen-2 sub-formations of the Nenjiang Formation to pinpoint favorable intervals for shale oil exploration. Through the integration of lithology, pressure, and fracture distribution data in the study area, favorable zones were delineated. The Nen-1 sub-formation is widely distributed in the Changling Depression, with mud shale thickness ranging from 30 to 100 m and a total organic content exceeding 2.0%. Type I kerogen predominated as the source rock, while some samples contained type II kerogen. Organic microcomponents primarily comprised algal bodies, with vitrinite reflectance (Ro) ranging from 0.5% to 0.8%. Compared to Nen-1 shale, Nen-2 shale exhibited less total organic content, kerogen type, and thermal evolution degree, albeit both are conducive to low-maturity shale oil generation. The Nen-1 and Nen-2 sub-formations predominantly consist of clay, quartz, feldspar, calcite, and pyrite minerals, with minor dolomite, siderite, and anhydrite. Hydrocarbons primarily reside in microfractures and micropores, including interlayer micropores, organic matter micropores, intra-cuticle micropores, and intercrystalline microporosity, with interlayer and intra-cuticle micropores being dominant. The free oil content (S1) in Nen-1 shale ranged from 0.01 mg/g to 5.04 mg/g (average: 1.13 mg/g), while in Nen-2 shale, it ranged from 0.01 mg/g to 3.28 mg/g (average: 0.75 mg/g). The Nen-1 and Nen-2 sub-formations are identified as potential intervals for shale oil exploration. Considering total organic content, oil saturation, vitrinite reflectance, and shale formation thickness in the study area, the favorable zone for low-maturity shale oil generation is primarily situated in the Heidimiao Sub-Depression and its vicinity. The Nen-2 shale-oil-enriched zone is concentrated in the northwest part of the Heidimiao Sub-Depression, while the Nen-1 shale-oil-enriched zone lies in the northeast part. Full article
(This article belongs to the Topic Petroleum Geology and Geochemistry of Sedimentary Basins)
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32 pages, 26323 KiB  
Article
Geochronology and Geochemical Characteristics of Granitoids in the Lesser Xing’an–Zhangguangcai Range: Petrogenesis and Implications for the Early Jurassic Tectonic Evolution of the Mudanjiang Ocean
by Jingui Kong, Kai Qiao, Xiaoyu Huo, Guobin Zhang, Xingkai Chen and Lei Yao
Minerals 2024, 14(9), 941; https://doi.org/10.3390/min14090941 - 15 Sep 2024
Viewed by 452
Abstract
This article focuses on zircon U-Pb isotope dating and a whole-rock elemental analysis of granodiorites, monzonitic granites, granodioritic porphyries, and alkali feldspar granites in the Yangmugang area of the Lesser Xing’an–Zhangguangcai Range. The zircon U-Pb isotope-dating results revealed that these granitic rocks formed [...] Read more.
This article focuses on zircon U-Pb isotope dating and a whole-rock elemental analysis of granodiorites, monzonitic granites, granodioritic porphyries, and alkali feldspar granites in the Yangmugang area of the Lesser Xing’an–Zhangguangcai Range. The zircon U-Pb isotope-dating results revealed that these granitic rocks formed during the late Early Jurassic period (182.9–177.2 Ma). Their geochemical characteristics and zircon saturation temperatures suggest that the granodiorites are moderately differentiated I-type granites and the monzonitic granite, granodioritic porphyries, and alkali feldspar granites are highly differentiated I-type granites. The degree of magma differentiation progressively increased from granodiorites to alkali feldspar granites. By combining the regional Nd and Hf isotope compositions, it was inferred that the magma source involved the melting of lower crustal material from the Mesoproterozoic to the Neoproterozoic eras. By integrating these findings with contemporaneous intrusive rock spatial variations, it was indicated that the late Early Jurassic granitoids in the Lesser Xing’an–Zhangguangcai Range formed within an extensional tectonic setting after the collision and closure of the Songnen–Zhangguangcai Range and Jiamusi blocks. Additionally, this study constrains the closure of the Mudanjiang Ocean to the late Early Jurassic period (177.2 Ma). Full article
(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)
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21 pages, 6955 KiB  
Article
Zircon U-Pb Ages of the Granitoids in Shanxi and Its Significance for Tectonic Evolution of North China Craton in Mesozoic
by Fuhui Qi, Pengpeng Li and Chao Liu
Minerals 2024, 14(9), 940; https://doi.org/10.3390/min14090940 - 15 Sep 2024
Viewed by 489
Abstract
Mesozoic granitoid formations offer crucial insights into the tectonic history of the North China Craton. New zircon U-Pb ages of two Mesozoic granitoids in the Huai’an terrane yield ages of 226.4 ± 1.1 Ma for the Yihe (YH) granite and 156.3 ± 2.9 [...] Read more.
Mesozoic granitoid formations offer crucial insights into the tectonic history of the North China Craton. New zircon U-Pb ages of two Mesozoic granitoids in the Huai’an terrane yield ages of 226.4 ± 1.1 Ma for the Yihe (YH) granite and 156.3 ± 2.9 Ma for the Zhujiagou (ZJG) granodiorite. The negative Nb, Ta, and Ti anomalies; high Nb/Ta ratios (20.4 to 24.1); high (La/Yb)N (30–84); low initial 87Sr/86Sr ratios (0.707725–0.708188); and negative ƐNd(t) values of the Yihe complex suggest that it originated from the partial melting of the lower crust and lithospheric mantle. However, the geochemical and Sr-Nd isotopic results of the ZJG granodiorite are characterized by I-type granites: Na2O + K2O values of 7.27 to 7.94 wt%, negative Nb anomalies, positive Pb anomalies, higher initial 87Sr/86Sr ratios (0.710979–0.714841), and much lower ƐNd(t) values (−27.1 to −30.1). The Late Jurassic Zhujiagou complex was derived from partial melting of a thickened low crust, and during the Late Triassic, magmatic rocks were formed under a post-collisional extensional regime. Multiple upwellings of the asthenosphere facilitated the mixing of magmas derived from partial melting of the lithospheric mantle and lower crust. These mixed magmas then ascended to the upper crust after undergoing fractional crystallization, leading to the formation of the YH complex. In the Late Jurassic, the tectonic regime of the NCC shifted from compression to extension. The Late Jurassic intrusion identified in this study developed within a compressional setting linked to the subduction of the Paleo-Pacific Ocean. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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22 pages, 12371 KiB  
Article
The Fate of “Immobile” Ti in Hyaloclastites: An Evidence from Silica–Iron-Rich Sedimentary Rocks of the Urals Paleozoic Massive Sulfide Deposits
by Nuriya R. Ayupova, Valery V. Maslennikov, Irina Yu. Melekestseva, Dmitry A. Artemyev and Elena V. Belogub
Minerals 2024, 14(9), 939; https://doi.org/10.3390/min14090939 - 13 Sep 2024
Viewed by 581
Abstract
The formation of Paleozoic silica–iron-rich sedimentary rocks in the Urals volcanic-hosted massive sulfide (VHMS) deposits is considered a result of seafloor alteration of hyaloclastites mixed with calcareous/organic or sulfide material. These rocks host various Ti mineral phases pointing to the transformation of precursor [...] Read more.
The formation of Paleozoic silica–iron-rich sedimentary rocks in the Urals volcanic-hosted massive sulfide (VHMS) deposits is considered a result of seafloor alteration of hyaloclastites mixed with calcareous/organic or sulfide material. These rocks host various Ti mineral phases pointing to the transformation of precursor metacolloidal TiO2 phases to disordered anatase during seafloor alteration of hyaloclastites, which was later converted to globules and clusters and further to diagenetic rutile. The LA-ICP-MS analysis showed that the Ti content of hyaloclasts partly replaced by finely dispersed Si–Fe aggregates increases to 540–2950 ppm and decreases (<5 ppm) in full Si–Fe pseudomorphs after hyaloclasts. LA-ICP-MS element mapping reveals the enrichment in V, U, Cr, W, Nb, Pb, and Th of the anatase globules and the local accumulation of Zr, Y, and REE on their periphery. Corrosive biogenic textures in the outer zones of some hyaloclasts and biomorphic aggregates in rocks contain anatase particles in assemblage with apatite indicating the biophilic properties of Ti. This work fills the knowledge gaps about Ti mobilization during low-temperature seafloor alteration of hyaloclastites in VHMS deposits. Full article
(This article belongs to the Special Issue Mineralization and Geochemistry of VMS Deposits)
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13 pages, 4474 KiB  
Article
Experimentation of Heat-Insulating Materials for Surrounding Rocks in Deep Mines and Simulation Study of Temperature Reduction
by Hongwei Deng and Yuanzhe Xiao
Minerals 2024, 14(9), 938; https://doi.org/10.3390/min14090938 - 13 Sep 2024
Viewed by 541
Abstract
With the increasing depletion of shallow resources, mining has gradually shifted to deeper levels, and the high-temperature problem of deep mining has restricted the efficient and safe development of mining. In this study, five types of thermal insulation materials for surrounding rocks with [...] Read more.
With the increasing depletion of shallow resources, mining has gradually shifted to deeper levels, and the high-temperature problem of deep mining has restricted the efficient and safe development of mining. In this study, five types of thermal insulation materials for surrounding rocks with different ratios were produced using tailings, P.O.32.5 clinker, aluminum powder, glass beads, quick lime, and slaked lime as test materials. Based on the uniaxial compression test, the thermal constant analysis test, and numerical simulation analysis technology, the change rule of mortar compressive strength and thermal conductivity was analyzed, and the cooling effect of surrounding-rock thermal insulation materials with different ratios was discussed. The results showed that the compressive strength of the surrounding-rock thermal insulation materials ranged from 0.39 to 0.53 MPa, and the thermal conductivity ranged from 0.261 to 0.387 W/(K·m), with the compressive strength of ratio E being the largest and the thermal conductivity of ratio A being the lowest. In the numerical simulation analysis results, the thermal insulation layer thickness was taken as a value of 10 cm when, at this time, the best thermal insulation effect and economic benefits involved a temperature reduction of 0.9 K. In the case of changing the thermal conductivity and inlet wind speed, the original temperature of the rock temperature reduction was also very clear, with maximum reductions of 0.92 K, 0.92 K, and 1.42 K. Full article
(This article belongs to the Special Issue Metallurgy Waste Used for Backfilling Materials)
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27 pages, 11927 KiB  
Article
Nature of Scapolite Color: Ab Initio Calculations, Spectroscopy, and Structural Study
by Roman Shendrik, Nikita V. Chukanov, Alexander Bogdanov, Alexandra Myasnikova, Elizaveta Pankrushina, Anatoly A. Zolotarev, Anastasiia Babkina, Ekaterina Popova, Marina F. Vigasina, Sergey M. Aksenov, Grigoriy Ilyin and Igor V. Pekov
Minerals 2024, 14(9), 937; https://doi.org/10.3390/min14090937 - 13 Sep 2024
Viewed by 702
Abstract
The article describes the results of a comprehensive study of the extra-framework components of scapolites using quantum–chemical calculations, electronic and vibrational spectroscopy, and single-crystal X-ray diffraction and crystal structure refinement. The ab initio calculations were performed using an embedded-cluster approach of extra-framework components [...] Read more.
The article describes the results of a comprehensive study of the extra-framework components of scapolites using quantum–chemical calculations, electronic and vibrational spectroscopy, and single-crystal X-ray diffraction and crystal structure refinement. The ab initio calculations were performed using an embedded-cluster approach of extra-framework components in various cation surroundings. As a result, through comparing the experimental and ab initio calculation results, the energies of the electronic and vibrational transitions of various extra-framework components (CO3)2−, (CO3)·−, S3·−, S2·−—as well as the role of these components in the process of the lowering of the symmetry—were determined for scapolites belonging to the marialite–meionite solid–solution series. The nature of the various colors of the scapolites has also been established. Colors from purple to blue are a result of the presence of radiation-induced pairs of defects: carbonate radical anions (CO3)·− and F-centers. However, polysulfide S3·− radical anions are found in some violet scapolites. Full article
(This article belongs to the Special Issue Crystal Structure, Mineralogy, and Geochemistry of Scapolite)
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24 pages, 13494 KiB  
Article
Geology and Geochemistry of the Hongnipo Copper Deposit, Southwest China
by Wangdong Yang, Gongwen Wang and Yunchou Xu
Minerals 2024, 14(9), 936; https://doi.org/10.3390/min14090936 - 13 Sep 2024
Viewed by 454
Abstract
The Hongnipo deposit, a newly discovered large copper deposit in the Kangdian Fe-Cu metallogenic belt of southwest China, is hosted in the Paleoproterozoic metavolcanic and metasedimentary rocks of the Hekou group. The deposit comprises five strata-bound ore bodies and is associated with sporadically [...] Read more.
The Hongnipo deposit, a newly discovered large copper deposit in the Kangdian Fe-Cu metallogenic belt of southwest China, is hosted in the Paleoproterozoic metavolcanic and metasedimentary rocks of the Hekou group. The deposit comprises five strata-bound ore bodies and is associated with sporadically distributed gabbroic intrusions. Four stages of mineralization and alteration have been identified: sodic alteration (I), banded sulfide (II), magnetite (III), and sulfide vein/stockwork (IV). Extensive sodic alteration of stage I is confirmed by the composition of feldspars. Trace element analysis of magnetite suggests a formation temperature of 400 ± 50 °C and has a characteristic of IOCG deposits, while high δ18O values (8.3–11.0‰) of fluids from stage III indicate a magmatic water origin. Sulfide δ34SVCDT values from stages II and IV range from −2.6 to 10.9‰ and −1.5 to 9.9‰, respectively, suggesting a mixed sulfur source from magmatic H2S and reduced seawater sulfate. Chalcopyrite from Hongnipo shows a narrow δ65Cu range of −0.135 to 0.587‰, indicating formation at high temperatures. The lack of correlation between δ65Cu and δ34SVCDT values suggests distinct geochemical behaviors in mineralization. In summary, the Hongnipo deposit is classified as a Cu-rich section of a typical IOCG deposit. Full article
(This article belongs to the Special Issue Geology, Geochemistry, Genesis, Modeling, Structure and Exploration of Copper Polymetallic Deposits)
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6 pages, 16630 KiB  
Brief Report
First Record of Romanechite in the Apulian Karst (Southern Italy) Resulting from the Interaction of Limestones and Clay Minerals
by Annamaria Fornelli, Francesca Micheletti, Pasquale Acquafredda and Annarosa Mangone
Minerals 2024, 14(9), 935; https://doi.org/10.3390/min14090935 - 13 Sep 2024
Viewed by 415
Abstract
A new occurrence of the Mn-Ba ore mineral, romanechite, has been discovered in a small paleo-doline of the Apulian karst on Mesozoic carbonate rock successions, characterized by reddish incrustations and nodules made essentially by Fe-bearing calcite. The conditions under which Mn-Ba ore minerals [...] Read more.
A new occurrence of the Mn-Ba ore mineral, romanechite, has been discovered in a small paleo-doline of the Apulian karst on Mesozoic carbonate rock successions, characterized by reddish incrustations and nodules made essentially by Fe-bearing calcite. The conditions under which Mn-Ba ore minerals form represent an intriguing area of research, as these minerals can act as scavengers for heavy elements, impacting soils, surface sediments, and even associated aquatic systems. The genesis of romanechite is linked to the progressive interaction of silicate aqueous solutions enriched in Al, Si, and Fe with the limestone substrate. The findings provide new insights into the genetic processes responsible for the formation of reddish Mn incrustations, supporting their polygenetic origin because of the chemical alteration of limestone and allochthonous siliciclastic muds. Full article
(This article belongs to the Section Clays and Engineered Mineral Materials)
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13 pages, 14435 KiB  
Article
Spread Spectrum Induced Polarization (SSIP) Survey for the Qiushuwan Copper–Molybdenum Deposits in Southern Henan Province, China
by Jawad Ahmad, Rujun Chen, Ijaz Ahmed, Muhammad Yaseen, Shahid Ali Shah, Osama Abdul Rahim, Farid Ullah, Shah Fahad and Li Rui
Minerals 2024, 14(9), 934; https://doi.org/10.3390/min14090934 - 13 Sep 2024
Viewed by 753
Abstract
The Qiushuwan Cu-Mo deposit, situated in the East Qinling molybdenum belt, is a notable mining site renowned for its considerable quantities of medium-sized molybdenum. The goal of this study is to improve comprehension and identify additional mineral resources by conducting a thorough examination [...] Read more.
The Qiushuwan Cu-Mo deposit, situated in the East Qinling molybdenum belt, is a notable mining site renowned for its considerable quantities of medium-sized molybdenum. The goal of this study is to improve comprehension and identify additional mineral resources by conducting a thorough examination of the mine using the spread spectrum-induced polarization (SSIP) technique. Gathering SSIP data, conducting geological investigations, and examining the electrical characteristics of rock and mineral samples along Profile-80 led to significant discoveries. The investigation identified two significant ore bodies with high conductivity: C2, linked to granite porphyry and molybdenum veins, and C4, associated with a skarn deposit containing a concentrated amount of copper ore. This study used resistivity models created from SSIP data to find out how conductivity changed in different parts of the research area. Additional drill verifications validated these findings, indicating the presence of potential mineral resources. The petrographic analysis of core samples showed that minerals like pyrite, molybdenite, chalcopyrite, epidote, calcite, and garnet were present. Notably, the samples frequently contained both pyrite and molybdenite together. Sample 04-2 contained substantial quantities of molybdenite and pyrite; Sample 05-1 had occasional pyrite; and Sample 07-4 included both pyrite and chalcopyrite. These findings offer useful insights for evaluating the magnitude and economic feasibility of the mineral deposits; however, additional investigation is required to completely comprehend the scope of the resources. The integration of borehole data and the alignment of geological sections with inversion models confirmed the validity of the conclusions. The core samples that were retrieved show a lot of different minerals, including valuable ores and minerals that have been changed. Pyrite and molybdenite are always found together. These findings establish a solid basis for further investigation and the sustainable management of resources. This study contributes to the understanding of the Qiushuwan Cu-Mo deposit and advances exploration techniques using the spread spectrum-induced polarization (SSIP) method. It provides useful information for geologists, mining professionals, and stakeholders involved in resource usage. Full article
(This article belongs to the Section Mineral Exploration Methods and Applications)
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21 pages, 9535 KiB  
Article
Petrogenesis of Eocene A-Type Granite Associated with the Yingpanshan–Damanbie Regolith-Hosted Ion-Adsorption Rare Earth Element Deposit in the Tengchong Block, Southwest China
by Zhong Tang, Zewei Pan, Tianxue Ming, Rong Li, Xiaohu He, Hanjie Wen and Wenxiu Yu
Minerals 2024, 14(9), 933; https://doi.org/10.3390/min14090933 - 12 Sep 2024
Viewed by 425
Abstract
The ion-adsorption-type rare earth element (iREE) deposits dominantly supply global resources of the heavy rare earth elements (HREEs), which have a critical role in a variety of advanced technological applications. The initial enrichment of REEs in the parent granites controls the formation of [...] Read more.
The ion-adsorption-type rare earth element (iREE) deposits dominantly supply global resources of the heavy rare earth elements (HREEs), which have a critical role in a variety of advanced technological applications. The initial enrichment of REEs in the parent granites controls the formation of iREE deposits. Many Mesozoic and Cenozoic granites are associated with iREE mineralization in the Tengchong block, Southwest China. However, it is unclear how vital the mineralogical and geochemical characteristics of these granites are to the formation of iREE mineralization. We conducted geochronology, geochemistry, and Hf isotope analyses of the Yingpanshan–Damanbie granitoids associated with the iREE deposit in the Tengchong block with the aims to discuss their petrogenesis and illustrate the process of the initial REE enrichment in the granites. The results showed that the Yingpanshan–Damanbie pluton consists of syenogranite and monzogranite, containing REE-bearing accessory minerals such as monazite, xenotime, apatite, zircon, allanite, and titanite, with a high REE concentration (210–626 ppm, mean value is 402 ppm). The parent granites have Zr + Nb + Ce + Y (333–747 ppm) contents and a high FeOT/MgO ratio (5.89–11.4), and are enriched in Th (mean value of 43.6 ppm), U (mean value of 4.57 ppm), Zr (mean value of 305 ppm), Hf (mean value of 7.94 ppm), Rb (mean value of 198 ppm), K (mean value of 48,902 ppm), and have depletions of Sr (mean value of 188 ppm), Ba (mean value of 699 ppm), P (mean value of 586 ppm), Ti (mean value of 2757 ppm). The granites plot in the A-type area in FeOT/MgO vs. Zr + Nb + Ce + Y and Zr vs. 10,000 Ga/Al diagrams, suggesting that they are A2-type granites. These granites are believed to have formed through the partial melting of amphibolites at a post-collisional extension setting when the Tethys Ocean closed. REE-bearing minerals (e.g., apatite, titanite, allanite, and fluorite) and rock-forming minerals (e.g., potassium feldspar, plagioclase, biotite, muscovite) supply rare earth elements in weathering regolith for the Yingpanshan–Damanbie iREE deposit. Full article
(This article belongs to the Special Issue Petrogenesis of Large Igneous Province and Rare Earth–Rare Metal Deposits)
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23 pages, 10947 KiB  
Review
The Role of Organic Matter and Hydrocarbons in the Genesis of the Pb-Zn-Fe (Ba-Sr) Ore Deposits in the Diapirs Zone, Northern Tunisia
by Larbi Rddad, Nejib Jemmali and Samar Jaballah
Minerals 2024, 14(9), 932; https://doi.org/10.3390/min14090932 - 12 Sep 2024
Viewed by 1076
Abstract
Extensional tectonics along NE-trending faults, coupled with diapirism, created paleo-highs and subsiding basins, providing the structural framework for subsequent mineralization processes. The preservation of organic matter within the Fahdene and Bahloul Cretaceous formations during the Anoxic Oceanic Events (AOE-1 and AOQ-2) facilitated the [...] Read more.
Extensional tectonics along NE-trending faults, coupled with diapirism, created paleo-highs and subsiding basins, providing the structural framework for subsequent mineralization processes. The preservation of organic matter within the Fahdene and Bahloul Cretaceous formations during the Anoxic Oceanic Events (AOE-1 and AOQ-2) facilitated the extraction of metals from seawater. The association of metals with organic matter, Fe-Mg oxides, and pyrite is revealed by principal component analysis (PCA). The subsequent maturation of organic matter generated hydrocarbons, with thermal cracking leading to the incorporation of organo-metallic ligands into mobile hydrocarbons. Oilfield brines form as a byproduct of this catagenesis. The metal-rich hydrocarbons and basinal brines invaded SO4−2-rich fluids from Triassic evaporites, resulting in the precipitation of sulfates (barite and celestite) and the bacteriogenic (BSR) and/or thermal (TSR) reduction of sulfate to reduced sulfur, which combined with metals to form sulfide ores. This study examines the role of hydrocarbons in the genesis of ore deposits within the diapiric zone, drawing upon a synthesis of literature and geological data. It highlights the interplay between basinal evolution, the organic matter-rich Cretaceous formations (Fahdene and Bahloul), diapiric paleo-highs, and the Alpine orogeny, which are identified as crucial factors in ore genesis in the diapiric zone. Full article
(This article belongs to the Special Issue The Role of Hydrocarbons in the Genesis of Mineral Deposits)
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22 pages, 4005 KiB  
Article
Distribution of Heavy Metals along the Mediterranean Shoreline from Baltim to El-Burullus (Egypt): Consequences for Possible Contamination
by Rehab A. Seif, Antoaneta Ene, Hesham M. H. Zakaly, Asmaa M. Sallam, Sherif A. Taalab, Mohammed S. Fnais, Diaa A. Saadawi, Shaimaa A. Amer and Hamdy A. Awad
Minerals 2024, 14(9), 931; https://doi.org/10.3390/min14090931 - 12 Sep 2024
Viewed by 683
Abstract
This work is mainly concerned with the effect of anthropogenic activities, the presence of black sand spots, factory construction, and shipping, in addition to other activities like agriculture, on soil heavy metal pollution along the Mediterranean shores of Lake El-Burullus, Egypt, to assess [...] Read more.
This work is mainly concerned with the effect of anthropogenic activities, the presence of black sand spots, factory construction, and shipping, in addition to other activities like agriculture, on soil heavy metal pollution along the Mediterranean shores of Lake El-Burullus, Egypt, to assess the contamination levels and to identify possible sources and the distribution of these metals. This study focuses on the various heavy metal contamination levels in El-Burullus Lake coastal sediments. Sediment samples were collected and analyzed by the XRF technique for heavy metals, including Cr, Cu, Ni, Zn, Zr, Pb, Ba, Sr, Ga, Rb, V, and Nb. Statistical analyses, including correlation coefficient, factor analysis, and cluster analysis, were employed to understand the interactions and sources of these metals. The highest concentrations recorded were for Zr (84–1436 mg/kg) and Pb (1–1166 mg/kg), with average concentrations of 455.53 mg/kg and 79.27 mg/kg, respectively. Cr, Zr, Nb, and Pb showed average values higher than the average shale concentration, indicating potential pollution. Correlation analysis revealed strong associations between several metals, suggesting common sources of both natural and anthropogenic origin and similar distribution patterns. Factor analysis indicated four main factors accounting for 94.069% of the total variance, with the first factor heavily dominated by Cr, Ni, Zn, and Ba. The contamination factor (Cf) and degree (DC) analyses revealed varying contamination levels, with most metals exhibiting the greatest values in the western half of the area. The pollution load index (PLI) indicated high-quality sediment samples without significant pollution. Our findings highlight the importance of continued monitoring and management techniques to reduce possible environmental and health concerns associated with these pollutants. Full article
(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)
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15 pages, 9366 KiB  
Article
Study of the Genesis Process and Deep Prospecting Breakthrough in the Gouli Ore Concentration of the East Kunlun Metallogenic Belt Using Audio Magnetotelluric Data
by Ji’en Dong, Peng Wang, Hua Li, Huiqing Zhang, Mingfu Zhao, Haikui Tong, Xiaoliang Yu, Jie Li and Binshun Zhang
Minerals 2024, 14(9), 930; https://doi.org/10.3390/min14090930 - 12 Sep 2024
Viewed by 348
Abstract
The East Kunlun Orogenic Belt is an essential part of the Qin-Qikun composite orogenic system, the most crucial orogenic belt in Qinghai Province, and an important gold ore-producing area in China. The Gouli gold field in its eastern section is one of the [...] Read more.
The East Kunlun Orogenic Belt is an essential part of the Qin-Qikun composite orogenic system, the most crucial orogenic belt in Qinghai Province, and an important gold ore-producing area in China. The Gouli gold field in its eastern section is one of the most important gold fields discovered in the belt in recent years. The Mailong mining area is an important gold mining area in the Gouli ore-concentrated area. The area has experienced frequent and intense magmatic activity, with intrusive rock bodies extensively exposed and intersected by a complex network of fault structures, providing excellent geological conditions for the formation of gold deposits. However, it is difficult to explore due to high altitude, poor transportation, and shallow coverage. This study used an audio magnetotelluric sounding method to track the deep direction and inclination of known mineral belts in the Mailong mining area, and identified mineral exploration targets, providing a basis for mineral exploration. Subsequently, a gold ore body was discovered through drilling verification, achieving a breakthrough in deep mineral exploration. The electromagnetic exploration method works well for exploring structurally altered rock-type gold deposits in plateau desert areas, and combined with the results of this electromagnetic exploration, a metallogenic geological model and genesis process of the Mailong mining area has been constructed. Full article
(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)
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