Journal Description
Minerals
Minerals
is an international, peer-reviewed, open access journal of natural mineral systems, mineral resources, mining, and mineral processing. Minerals is published monthly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), GeoRef, CaPlus / SciFinder, Inspec, Astrophysics Data System, AGRIS, and other databases.
- Journal Rank: JCR - Q2 (Mining & Mineral Processing) / CiteScore - Q2 (Geology)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 17 days after submission; acceptance to publication is undertaken in 2.5 days (median values for papers published in this journal in the first half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Companion journal: Mining
Impact Factor:
2.5 (2022);
5-Year Impact Factor:
2.7 (2022)
Latest Articles
Global Crystallographic Texture of Pyrite in Fossil Wood (Jurassic, Oryol Region, Russia)
Minerals 2023, 13(8), 1050; https://doi.org/10.3390/min13081050 - 08 Aug 2023
Abstract
Many works are devoted to the study of the crystallographic texture of primary skeletal minerals of animals. But how the directions of mineral crystals that replace the organic matter in the fossil state are oriented is unknown. Here we investigated the crystallographic texture
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Many works are devoted to the study of the crystallographic texture of primary skeletal minerals of animals. But how the directions of mineral crystals that replace the organic matter in the fossil state are oriented is unknown. Here we investigated the crystallographic texture of pyrite grown on an organic matrix and without it. Jurassic pyritized wood (Middle Jurassic, Callovian) was studied by the neutron diffraction method. The global crystallographic texture of pyrite in nodules and fossil wood is compared. It was found that in both cases, the isoline patterns of pole figures and texture sharpness are similar to the same characteristics of abiogenic calcite. But the orientations of pyrite crystals in wood are more ordered, the isolines are closer, and the regions of maximum pole density are wider. That is, the pyrite crystals that replaced the petrified wood are more ordered. This was influenced by the organic matrix on which the crystals grew. Repetition of a fossil mollusk shell shape without using its shell as a matrix for crystal growth does not lead to an increase in the crystallographic texture sharpness. This is illustrated by an example of the inner core calcite shell of the gastropod mollusk Bellerophon sp.
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(This article belongs to the Special Issue Biomineralization in Prokaryotes and Eukaryotes)
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Color Origin of Greyish-Purple Tremolite Jade from Sanchahe in Qinghai Province, NW China
Minerals 2023, 13(8), 1049; https://doi.org/10.3390/min13081049 - 07 Aug 2023
Abstract
Greyish-purple tremolite jade has become well known in the past few years, and the origin of its color has attracted the attention of gemologists. In this study, FT-IR spectra, EPMA, EPR spectra, micro-XRF, UV–Vis–NIR spectra, and LA-ICP-MS in situ mapping were analyzed to
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Greyish-purple tremolite jade has become well known in the past few years, and the origin of its color has attracted the attention of gemologists. In this study, FT-IR spectra, EPMA, EPR spectra, micro-XRF, UV–Vis–NIR spectra, and LA-ICP-MS in situ mapping were analyzed to investigate the chromophore elements. The study sample was chosen from the Sanchahe mine, Qinghai Province, NW China, which has the typical characteristics of a gradual color change. The FT-IR and EPMA results revealed that the mineral composition of the dark and light greyish-purple regions of the sample are primarily composed of tremolite. UV–Vis–NIR spectra demonstrated that the greyish-purple color is mainly due to strong absorptions at 560 nm and 700 nm and weak absorption at 745 nm in the visible range. The EPR spectra presented ~3400 G six hyperfine lines resulting from the hyperfine interactions of the unpaired electron with the Mn2+ nucleus in the octahedral site. The UV–Vis–NIR and EPR spectra analyses demonstrated that Mn2+ is the origin of the purple color. A comparison of the major elements in the light and dark regions indicated that the chromogenic elements have strong positive correlations with Mn, Cu, and Fe. LA-ICP-MS mapping used to analyze the first transition metals indicated possible positive correlations between the greyish-purple color and the trace chromogenic elements. This suggested that the Mn, Cu, and Fe contents are significantly high in the dark band region. Combining in situ LA-ICP-MS mapping of trace elements, UV–Vis spectra, and EPR analysis results, it was suggested that Mn, Cu, and Fe are the major contributors to the greyish-purple color. This study provides a reference for the specific experimental methods to determine chromophores and the origin of color in tremolite jades.
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(This article belongs to the Special Issue Gem Deposits: Mineralogical and Gemological Aspects)
Open AccessArticle
Distribution of Potentially Toxic Elements in the City of Zintan and Its Surroundings (Northwestern Libya) by Surface Soil Sampling
by
, , , , , , and
Minerals 2023, 13(8), 1048; https://doi.org/10.3390/min13081048 - 07 Aug 2023
Abstract
The study area is the city of Zintan, in northwestern Libya, which has grown over the past 30 years. Its current population is roughly 30,000. Although the city is in part commercial, most of the population engages in agriculture and primarily grows cereal
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The study area is the city of Zintan, in northwestern Libya, which has grown over the past 30 years. Its current population is roughly 30,000. Although the city is in part commercial, most of the population engages in agriculture and primarily grows cereal crops (wheat and barley). The demand of the growing city for agricultural products has increased, intensifying the use of fertilizers, pesticides, and insecticides. Consequently, concentrations of potentially toxic elements (PTE) in the soil have increased. To assess the soil quality (to provide a snapshot of the condition of the soil), systematic sampling was undertaken across a grid of about 2 km × 2 km. The main objective was to determine the chemical and mineral composition of the area of interest, keeping in mind the geological footprint of the terrain. The geologic framework itself is not conducive to elevated concentrations of elements like U, Th, Mo, As, Hg, Pb, and Cr. Therefore, metal concentrations greater than the amounts in the Earth’s crust are most likely of anthropogenic origin. A total of 143 samples were collected and chemical analyses were performed using a Thermo Fisher Scientific Niton XL3t GOLDD+ XRF analyzer for the following elements: Mo, Zr, Sr, U, Rb, Th, Pb, Au, Se, As, Hg, Zn, W, Cu, Ni, Co, Fe, Mn, Cr, V, Ti, Sc, Ca, K, S, Ba, Cs, Te, Sb, Sn, Cd, Pd, and Ag. This paper provides examples of elevated concentrations, potentially harmful to the environment, such as those of the following: sulfur of unknown origin (two to three times higher than the Earth’s crust average); arsenic, given that there are no related natural phenomena (all the samples measured displayed concentrations higher than those found in the Earth’s crust); mercury (concentrations much higher than permissible levels); cesium (additional investigations required to determine the origin); molybdenum; and uranium likely resulting from the use of superphosphates (concentrations nearly always significantly higher than those in the Earth’s crust).
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(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)
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Microstructural Insights into the Evolution of Ophiolitic Chromite from Luobusha
Minerals 2023, 13(8), 1047; https://doi.org/10.3390/min13081047 - 07 Aug 2023
Abstract
The podiform chromitite found within the Luobusha ophiolite comprises characteristic nodules and massive chromitites. However, the exact origin of these formations remains a topic of ongoing debate. In this study, the microstructures of olivine and chromite are investigated to unravel their formation processes
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The podiform chromitite found within the Luobusha ophiolite comprises characteristic nodules and massive chromitites. However, the exact origin of these formations remains a topic of ongoing debate. In this study, the microstructures of olivine and chromite are investigated to unravel their formation processes and shed light on the associated geodynamic mechanisms. EBSD analysis provides insights into chromitite and host peridotite deformation mechanisms. Olivine grains in the host dunite and nodular chromite exhibit crystallographic preferred orientations (CPOs) with D-type fabrics, which show a girdle distribution in the [010] and [001] axes, normal to the foliation plane of the sample. The massive and disseminated chromitite displays B-type and C-type olivine fabric, with a concentration of [001] axes parallel to the lineation of the sample. Crystal plastic deformation can be observed in the Luobusha chromite grains, highlighting intercrystalline deformation processes. Small grains lacking misorientation observed in the massive chromitite are likely attributed to heterogeneous nucleation. Chromite nodules are found to be a patchwork of subgrains with various orientations and high-angle boundary misorientation. The formation of Luobusha chromitite involves deep-seated crystallization, followed by amalgamation, and subsequent deformation within the mantle peridotite. These findings distinguish Luobusha chromitite from other ophiolitic chromite deposits, offering valuable insights into the deformation history and formation processes.
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(This article belongs to the Section Crystallography and Physical Chemistry of Minerals & Nanominerals)
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Using 1D Thermal Modeling to Evaluate Formation Models of Mafic-Ultramafic Intrusions and Associated Sulfide Cu-Ni-PGE Mineralization
Minerals 2023, 13(8), 1046; https://doi.org/10.3390/min13081046 - 06 Aug 2023
Abstract
In this paper, we trace the thermal history of the mafic–ultramafic intrusions of the Monchegorsk (MC), Fedorova–Pana (FPC), and Norilsk ore-bearing complexes (NC) using an upgraded version of the author’s software Gehenna 2.2. It is shown that a key role in the concentration
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In this paper, we trace the thermal history of the mafic–ultramafic intrusions of the Monchegorsk (MC), Fedorova–Pana (FPC), and Norilsk ore-bearing complexes (NC) using an upgraded version of the author’s software Gehenna 2.2. It is shown that a key role in the concentration of sulfides in the lower parts of the intrusions belongs to the preliminary heating of the host rocks by early magmatic influxes. In the presence of late ore-bearing magmatic phases of a relatively small volume, the pattern of sulfide distribution within such a phase can be used to estimate the time gap with the main influx. Thermal modeling shows that the Gabbro-10 massif, an additional ore-bearing phase of the Nyud-Poaz intrusion of the MC, is separated from the main influx by a time gap of no more than 100 ka, while the minimum gap between the magmatic phases of the Fedorova intrusion of the FPC is 650–700 ka. The development of a hornfels halo around mafic–ultramafic rocks makes it possible to estimate the duration of the process of continuous magma flow inside intrusions, which, as an example from the Kharaelakh intrusion of the NC shows, can reach 1000 years and more. Thermal modeling is recommended both for formulating genetic hypotheses and for testing different scenarios for the formation of sulfide Cu-Ni-PGE mineralization in mafic–ultramafic complexes.
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(This article belongs to the Special Issue Mafic-Ultramafic Layered Intrusions: Genesis, Composition and Mineralization)
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The Mechanism of Viscosity-Enhancing Admixture in Backfill Slurry and the Evolution of Its Rheological Properties
Minerals 2023, 13(8), 1045; https://doi.org/10.3390/min13081045 - 06 Aug 2023
Abstract
Since filling slurry is a cement-based material, viscosity-enhancing admixture exerts a significant effect on its rheological performance and mechanical properties. Viscosity-enhancing admixture can improve pipeline transportation performance and reduce pipeline wear during the filling process of a kilometer-deep mine by changing the plastic
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Since filling slurry is a cement-based material, viscosity-enhancing admixture exerts a significant effect on its rheological performance and mechanical properties. Viscosity-enhancing admixture can improve pipeline transportation performance and reduce pipeline wear during the filling process of a kilometer-deep mine by changing the plastic viscosity and yield stress of high-concentration filling slurries. In order to reveal the influence mechanism of viscosity-enhancing admixture on rheological performance in slurry, the influence of viscosity-enhancing admixture on the rheological performance of slurry is explored by adjusting viscosity-enhancing admixture dosage and conducting bleeding test, liquidity test, and rheological performance test. The extended DLVO theory is employed to analyze the mechanism of HPMC on the stability of filling slurry. The results show that compared with ordinary slurry, after adding HPMC and XG, the particles of filling slurry are prone to link to form a mesh structure. Besides, the increasing frictional force between particles results in a significant decrease in the bleeding rate and liquidity of the slurry. Such an effect becomes more obvious with the increase of viscosity-enhancing admixture dosage. Meanwhile, the overall effect of HPMC molecules is better than that of XG molecules since HPMC can reduce inter-particle repulsion and facilitate particle aggregation. The optimal dosage is about 0.1%, at which time the yield stress of the filling slurry increases from 89.236 to 160.06 Pa, the plastic viscosity increases from 0.296 to 1.063 Pa·s, and the compressive strength increases from 2.58 to 3.59 MPa in 28 days. The study reveals the influence of viscosity-enhancing admixture on the rheological performance of filling slurry and its evolution characteristics, which provides theoretical support for the development of filling resistance and wear reduction technology.
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(This article belongs to the Special Issue Backfilling Materials for Underground Mining, Volume III)
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Heavy Metal Regularity of Carboniferous Weathered Black Shale in Qiziqiao Area, Central Hunan
Minerals 2023, 13(8), 1044; https://doi.org/10.3390/min13081044 - 06 Aug 2023
Abstract
The Hunan region is a high geological background area of black rock series rich in various metallic elements; accordingly, local heavy metal pollution is severe. Previous studies on black shale have primarily focused on the lower Cambrian strata, while research on Carboniferous black
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The Hunan region is a high geological background area of black rock series rich in various metallic elements; accordingly, local heavy metal pollution is severe. Previous studies on black shale have primarily focused on the lower Cambrian strata, while research on Carboniferous black shale remains scarce. To better explore the activity law of heavy metals during Carboniferous black shale weathering, this study analyzed the elemental components of samples through field observations of outcrops in the Qiziqiao area of central Hunan province, China using inductively coupled plasma mass spectrometry and X-ray fluorescence spectrometry. The results showed that the heavy metal content of black shale under different degrees of weathering varied greatly, with different heavy metals maintaining distinct migration and enrichment rules throughout this process. The heavy metal content in Carboniferous black shale and soils of central Hunan was generally less than that of the regional lower Cambrian black shale and soil; however, the Cd content in the black shale soil was slightly higher than background values, while the Sr content was substantially higher than background values. Heavy metals V, Cr, Co, Ni, Cu, and Pb were not generally leached or released during weathering, and may undergo relative enrichment or secondary enrichment. Comparatively, Zn, Cd, and Ba can be more readily leached and released, and may undergo secondary enrichment. The lithophilic element Sr tended to leach out overall and expressed strong activity, whereas the chemical activities of the high-field-strength elements, Zr and Hf, were relatively stable. During soil formation, all heavy metal elements save Sr were significantly enriched. The enrichment factor analysis of different degrees of weathered black shale reveals that the heavy metals Ba, Hf, and Sr in black shale soil originate from the parent rock. V, Cr, Co, Ni, Cu, Zn, Cd, and Pb are influenced by both natural and anthropogenic factors, with Cd being significantly impacted by human activities. The evaluation of soil heavy metals using the geoaccumulation index method indicates that V, Cr, Co, Ni, Cu, Zn, Zr, Ba, Hf, and Pb are non-polluted, Cd exhibits moderate pollution, and Sr shows moderately heavy pollution. From a geochemical perspective, it can be inferred that heavy metals in black shale soil are likely to be secondarily enriched in clay and iron oxide minerals.
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(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)
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Genesis and Geological Significance of Permian Oilfield Water in the Western Periphery of the Mahu Sag, Junggar Basin, China
Minerals 2023, 13(8), 1043; https://doi.org/10.3390/min13081043 - 06 Aug 2023
Abstract
Oilfield water contains valuable geological information and plays an important role in petroliferous basins, being closely related to diagenesis, reservoir physical properties, and hydrocarbon preservation conditions. Here we present a case study of oilfield water in Permian formations in the western periphery of
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Oilfield water contains valuable geological information and plays an important role in petroliferous basins, being closely related to diagenesis, reservoir physical properties, and hydrocarbon preservation conditions. Here we present a case study of oilfield water in Permian formations in the western periphery of the Mahu Sag, Junggar Basin, China. The genesis of oilfield water and its application in oil exploration were investigated through the coupling of tectonic activity, paleoclimate, and water–rock interaction. Volcanic activity provided a rich source of ions, and a hot paleoclimate intensifies the evaporation and concentration of sedimentary water. Tectonic fractures offered channels for water exchange among formations. Water–rock reactions, marked by sodic feldspathization and calcium feldspar dissolution, had profound effects on the oilfield water type and reservoir properties. We established a link between oilfield water and favorable targets for oil exploration. In terms of vertical trends, the Jiamuhe and Upper and Lower Urho formations have strong sealing abilities for hydrocarbon preservation. In the horizontal dimension, areas with high total-dissolved-solid and CaCl2 concentrations, low rNa/rCl, rSO4 × 100/rCl, (rHCO3+CO3)/rCa, and rMg/rCa ratios are favorable for oil exploration.
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(This article belongs to the Special Issue Advances in Fluid Inclusions and Geofluids)
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The Recovery of Gold in Low-Grade Cyanide Tailings by Chlorination Roasting
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, , , , , , and
Minerals 2023, 13(8), 1042; https://doi.org/10.3390/min13081042 - 04 Aug 2023
Abstract
The resource utilization of cyanide tailings has significant environmental and economic benefits. The efficient recovery of gold from low-grade cyanide tailings containing 1.71 g/t Au was performed by a chlorination roasting–flotation process. The effects of roasting temperature, calcium chloride, internal coke, external coke,
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The resource utilization of cyanide tailings has significant environmental and economic benefits. The efficient recovery of gold from low-grade cyanide tailings containing 1.71 g/t Au was performed by a chlorination roasting–flotation process. The effects of roasting temperature, calcium chloride, internal coke, external coke, copper sulfide concentrate, and kaolin on the recovery rate of concentrate, gold grade, and sorting efficiency were investigated. The optimized process parameters were as follows: 16 wt% calcium chloride dihydrate, 6 wt% internal carbon, 1 wt% external carbon, 9 wt% copper sulfide concentrate, 2 wt% kaolin, and roasting temperature of 730 °C. The sorting rate, gold grade, and recovery rate of gold concentrate can reach 88.48%, 33.46 g/t, and 76.7%, respectively, and the gold grade of tailings was as low as 0.17 g/t. In the matte phase, gold can be enriched in the form of gold grains. Therefore, through chlorination roasting, the trapped gold can be released and deposited on the surface of the matte phase due to the transformation from hematite to magnetite. The gold-deposited metal sulfide can be effectively recycled through flotation. These results have potential guiding significance for the efficient recovery of gold from cyanide tailings.
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(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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Unconformities and Gold in New Zealand: Potential Analogues for the Archean Witwatersrand of South Africa
Minerals 2023, 13(8), 1041; https://doi.org/10.3390/min13081041 - 04 Aug 2023
Abstract
Possible young analogues for regionally extensive unconformities (100 to 400 km2) in the gold-bearing Witwatersrand Supergroup (Archean, South Africa) occur in the South Island of New Zealand. Extensive marine unconformities in New Zealand show progression from an unconformity surface to conglomerate
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Possible young analogues for regionally extensive unconformities (100 to 400 km2) in the gold-bearing Witwatersrand Supergroup (Archean, South Africa) occur in the South Island of New Zealand. Extensive marine unconformities in New Zealand show progression from an unconformity surface to conglomerate to clean well-sorted sandstone to marine mudstone, as is also found in the major Witwatersrand auriferous reef horizons. The hosting young sedimentary basins of the South Island rest on thin or thick crust on inboard and outboard foreland settings, with variable alluvial gold budgets. They expose the Cretaceous–Oligocene Waipounamu Erosion Surface unconformity that formed when most of New Zealand was subsiding, and Pleistocene–Holocene unconformities related to global sea level changes. The Witwatersrand gold-bearing reef sediments are a good match for such marine transgressions, but not alluvial fans or braided streams. Most Witwatersrand gold is immediately above planar unconformity surfaces and not restricted to, or concentrated in, erosion channels that are incised through the reefs. However, in modern alluvial fans or braided streams, gold is almost entirely in erosion channels on a smaller scale than the Witwatersrand gold reef packages and not spread across the planar unconformities. Alluvial fans and braid plains in New Zealand dilute gold with large volumes of gravel.
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(This article belongs to the Special Issue Structure and Origin of Gold Mineralization: From Primary to Placer Gold Deposits)
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The Peritectic Reaction of Olivine as the Mechanism of the Ultrabasic–Basic Evolution of the Diamond-Forming Silicate-Carbonate-(C-O-H) System: Experiments at 6.0 GPa
Minerals 2023, 13(8), 1040; https://doi.org/10.3390/min13081040 - 04 Aug 2023
Abstract
Melting phase relations of the diamond-forming olivine (Ol)–jadeite (Jd)–diopside (Di)–(Mg, Fe, Ca, Na)-carbonates (Carb)–(C-O-H-fluid) system are studied in experiments at 6.0 GPa in the polythermal Ol74Carb18.5(C-O-H)7.5-Omp74Carb18.5(C-O-H)7.5 section, where Ol = Fo80
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Melting phase relations of the diamond-forming olivine (Ol)–jadeite (Jd)–diopside (Di)–(Mg, Fe, Ca, Na)-carbonates (Carb)–(C-O-H-fluid) system are studied in experiments at 6.0 GPa in the polythermal Ol74Carb18.5(C-O-H)7.5-Omp74Carb18.5(C-O-H)7.5 section, where Ol = Fo80Fa20, Omp (omphacite) = Jd62Di38 and Carb = (MgCO3)25(FeCO3)25(CaCO3)25(Na2CO3)25. The peritectic reaction of olivine and jadeite-bearing melts with formation of garnet has been determined as a physico-chemical mechanism of the ultrabasic–basic evolution of the diamond-forming system. During the process, the CO2 component of the supercritical C-O-H-fluid can react with silicate components to form additional carbonates of Mg, Fe, Ca and Na. The solidus temperature of the diamond-forming system is lowered to 1000–1020 °C by the joint effect of the H2O fluid and its carbonate constituents. The experimentally recognized peritectic mechanism of the ultrabasic–basic evolution of the diamond-forming system explains the origin of associated paragenetic inclusions of peridotite and eclogite minerals in diamonds, as well as the xenoliths of diamond-bearing peridotites and eclogites of kimberlitic deposits of diamond. Diamond-forming systems have formed with the use of material from upper mantle native peridotite rocks. In this case, the capacity of the rocks to initiate the peritectic reaction of olivine was transmitted with silicate components to diamond-forming systems.
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(This article belongs to the Special Issue Crystal Structures and Phase Transitions of Minerals at Extreme Conditions)
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Magmatic Evolution and Rare Metal Mineralization in Mount El-Sibai Peralkaline Granites, Central Eastern Desert, Egypt: Insights from Whole-Rock Geochemistry and Mineral Chemistry Data
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, , , , , , , , and
Minerals 2023, 13(8), 1039; https://doi.org/10.3390/min13081039 - 04 Aug 2023
Abstract
The Ediacaran peralkaline granites, which were emplaced during the post-collisional tectonic extensional stage, have a limited occurrence in the northern tip of the Nubian Shield. In this contribution, we present new mineralogical and geochemical data of Mount El-Sibai granites from the Central Eastern
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The Ediacaran peralkaline granites, which were emplaced during the post-collisional tectonic extensional stage, have a limited occurrence in the northern tip of the Nubian Shield. In this contribution, we present new mineralogical and geochemical data of Mount El-Sibai granites from the Central Eastern Desert of Egypt. The aim is to discuss their crystallization condition, tectonic setting, and petrogenesis as well as the magmatic evolution of their associated mineralization. Mount El-Sibai consists of alkali-feldspar granites (AFGs) as a main rock unit with scattered and small occurrences of alkali-amphibole granites (AAGs) at the periphery. The AAG contain columbite, nioboaeschynite, zircon and thorite as important rare metal-bearing minerals. Geochemically, both of AFG and AAG exhibit a highly evolved nature with a typical peralkaline composition (A/CNK = 0.82–0.97) and formed in within-plate anorogenic setting associated with crustal extension and/or rifting. They are enriched in some LILEs (Rb, K, and Th) and HFSEs (Ta, Pb, Zr, and Y), but strongly depleted in Ba, Sr, P and Ti with pronounced negative Eu anomalies (Eu/Eu* = 0.07–0.34), consistent with an A-type granite geochemical signature. The calculated TZrn (774–878 °C) temperatures indicate that the magma was significantly hot, promoting the saturation of zircon. The texture and chemistry of minerals suggest that they were crystallized directly from a granitic magma and were later subject to late- to post-magmatic fluids. Both granitic types were most likely generated through partial melting of a juvenile crustal source followed by magmatic fractionation. The lithospheric delamination is the main mechanism which causes uplifting of the asthenospheric melts and hence provides enough heat for crustal melting. The produced parent magma was subjected to prolonged fractional crystallization to produce the different types of Mount El-Sibai granites at different shallow crustal levels. During magma fractionation, the post-magmatic fluids (especially fluorine) contribute significantly to the formation of rare metal mineralization within Mount El-Sibai granites.
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(This article belongs to the Special Issue Petrogenesis, Geochronology, Mineralization and Geochemistry of Granite Rocks)
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Subduction–Accretion History of the Paleo-Pacific Plate Beneath the Eurasian Continent: Evidence from the Tongjiang Accretionary Complex, NE China
Minerals 2023, 13(8), 1038; https://doi.org/10.3390/min13081038 - 03 Aug 2023
Abstract
Detrital zircons in the matrix of an accretionary complex play an important role in providing evidence to reconstruct oceanic plate subduction and accretion processes. The Nadanhada accretionary complex (NAC) dominated by the Yuejinshan, Raohe and Tongjiang accretionary complexes provides significant geological evidence to
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Detrital zircons in the matrix of an accretionary complex play an important role in providing evidence to reconstruct oceanic plate subduction and accretion processes. The Nadanhada accretionary complex (NAC) dominated by the Yuejinshan, Raohe and Tongjiang accretionary complexes provides significant geological evidence to better understand the Paleo-Pacific subduction–accretion process. Most previous studies have focused on the Yuejinshan and Raohe accretionary complexes, while those of the Tongjiang accretionary complex on the north side have focused on blocks. In this study, we present zircon U–Pb dating and Hf isotopic data for the matrix of metasedimentary rock in the Tongjiang accretionary complex. The analysis results show that the zircons in the fine silty mudstone, phyllonite and fine argillaceous siltstone define the youngest weighted mean ages (youngest detrital zircon ages) of 261.4 ± 2.9 Ma (247 Ma), 175.2 ± 4.9 Ma (169 Ma) and 168.6 ± 2.1 Ma (162 Ma), respectively, and yield a younging trend of the accretion materials from west to east. Provenance analysis indicates that the matrix was mainly sourced from the neighboring Jiamusi and Xingkai blocks. Based on previous results of the Permian and Late Triassic blocks in the Yuejinshan region, the Permian and Early Jurassic blocks in the Tongjiang region, and the Late Triassic and Early–Middle Jurassic blocks in the Raohe region, as well as the lower limit of the depositional age of the Late Triassic matrix in the Yuejinshan region and the Middle Jurassic and Early Cretaceous matrices in the Raohe region, we propose that the NAC may record the Late Permian–Triassic, Jurassic and Early Cretaceous oceanic accretion events, representing the westward subduction and accretion process of the Paleo–Pacific Ocean Plate.
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(This article belongs to the Special Issue North China Craton: Geochemistry, Mineralogy and Tectonic Evolution)
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Uranium Occurrence State and Its Implication for Sandstone-Type Uranium Mineralization within the Hanbazhai Area of the Longchuanjiang Basin, China
Minerals 2023, 13(8), 1037; https://doi.org/10.3390/min13081037 - 03 Aug 2023
Abstract
The Mangbang Formation in the Hanbazhai area is part of the uranium ore field in the Longchuanjiang Basin, China. Uraniferous sandstones from this formation are examined in this study. The type and mode of occurrence of uranium are investigated in detail using an
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The Mangbang Formation in the Hanbazhai area is part of the uranium ore field in the Longchuanjiang Basin, China. Uraniferous sandstones from this formation are examined in this study. The type and mode of occurrence of uranium are investigated in detail using an experiment for the sequential extraction of uranium, as well as an electron probe, scanning electron microscopy, and energy spectrum analyses. The sequential extraction experiment indicates that the proportion of uranium minerals is significantly greater than that of the adsorbed uranium in the samples, with the latter being largely present in framboidal pyrites and clay minerals. The results show that these uranium minerals are mainly composed of coffinite and uranium phosphosilicates, which closely coexist with framboidal pyrites, carbon debris, feldspar minerals, and clay minerals. The discovery of coffinite and uranium phosphosilicates is discussed in context with their symbiotic relationship and geochemical environment. Uraniferous sandstones are considered to have undergone at least two stages of mineralization: the sedimentary–diagenetic stage and the later uranium enrichment by fluid. The geochemical environment of the sedimentary–diagenetic stage is generally a sulfide-reducing environment, and the later fluids are rich in U, Si, P, and Y.
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(This article belongs to the Topic Basin Analysis and Modelling)
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Trading Marble for Steel: Early Roman Import of Carrara Marble into the Alps—The Example of the Magdalensberg Trading Post in Noricum
Minerals 2023, 13(8), 1036; https://doi.org/10.3390/min13081036 - 02 Aug 2023
Abstract
The annexation of the Noricum Kingdom by the Roman Empire in 16 BC brought an increase in the trading relations between the empire and its northern neighbours. A first hub for these relations was the emporium on the Magdalensberg in Noricum Mediterraneum (today
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The annexation of the Noricum Kingdom by the Roman Empire in 16 BC brought an increase in the trading relations between the empire and its northern neighbours. A first hub for these relations was the emporium on the Magdalensberg in Noricum Mediterraneum (today southern Carinthia/Austria). During the last decades, archaeological investigations of this settlement in a remote mountainous area revealed, inter alia, different kinds of marble decoration and architecture. Provenance analyses using a combination of different methods, including isotope analysis, trace element analysis and the analysis of inclusion fluids, show that the marbles used on the Magdalensberg are of different origins. Widely used were medium- to coarse-grained Alpine marbles from Roman quarries of the region of Gummern. Prominently used for plates, tiles, profiles, etc. were several types of fine-grained marbles of different origins. One group definitely originated from the quarries of Carrara (Carrara white and Carrara Bardiglio), testifying to the trading relations with northern Italy after the integration of Noricum into the Roman Empire. A database for the Carrara Bardiglio marble is presented and discussed. For the use of these data by further investigators, the numerical data are given as online material.
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(This article belongs to the Special Issue Characterization and Provenance Analysis of Ancient Stone Materials: Insights from Mineralogy, Petrology and Geochemistry)
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Experimental Study on Pore Structure and Soil-Water Characteristic Curve of Ionic Rare Earth Ore under Seepage
Minerals 2023, 13(8), 1035; https://doi.org/10.3390/min13081035 - 02 Aug 2023
Abstract
The ionic rare earth (RE) ore body undergoes particle transport and pore structure change during the leaching process, resulting in "uneven percolation, preferential channel, leaching blind area," and other problems, leading to structural changes in the ore body, low leaching efficiency, and waste
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The ionic rare earth (RE) ore body undergoes particle transport and pore structure change during the leaching process, resulting in "uneven percolation, preferential channel, leaching blind area," and other problems, leading to structural changes in the ore body, low leaching efficiency, and waste of resources. The unsaturated infiltration process is also the key stage that causes these problems. The initial pore structure evolution of the ore body plays a decisive role in the permeability coefficient of the ore body, and the direct influencing factor of the permeability coefficient is the distribution of the pore radius. We carried out research through indoor simulated leaching, the filter paper method for determining matrix suction, and nuclear magnetic resonance (NMR) testing. An ionic rare earth ore soil-water characteristic curve within a large matrix suction range was obtained by the filter paper method. With the increase in volumetric water content, the matrix suction presents a sharp downward trend. When the volumetric water content is less than 20%, this rule is particularly obvious. With the increase in matrix suction, the thickness of the adsorbed water film on the particle surface and pore radius show a decreasing power function trend. Under percolation, the porosity of an ionic rare earth ore sample tends to increase linearly with the increase in volumetric water content during the process from non-saturation to saturation; the porosity of a saturated ore sample after seepage expanded by 17.5 times compared to that of an unsaturated ore sample before seepage. The change rule of the internal microstructure of the ore sample is reflected in the gradual disappearance of micro pores and the gradual formation of small, medium, large, and mega pores, which shows a gradual increase trend. In the pore radius distribution, the more large and medium pores, the larger the permeability coefficient; the more micro and small pores, the smaller the permeability coefficient. For some ore bodies with poor permeability, the ore body is infiltrated with clear water under small water pressure before leaching with a leaching solution, which can improve the permeability of the ore body, effectively improve the efficiency of rare earth leaching, and increase the economic benefits.
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(This article belongs to the Special Issue Recovery of Rare Earth Elements Minerals: 2nd Edition)
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Structure and Distribution of the Gold-Related Quartz Vein Systems in the Southwestern Part of the Barberton Greenstone Belt (South Africa, Eswatini)
Minerals 2023, 13(8), 1034; https://doi.org/10.3390/min13081034 - 01 Aug 2023
Abstract
This study investigates the structural control of the numerous gold occurrences in the southern part of the Barberton Greenstone Belt in the Malolotja and Steynsdorp areas. The gold-bearing event distribution is studied using field structural geology associated with a petrological and microstructural analysis.
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This study investigates the structural control of the numerous gold occurrences in the southern part of the Barberton Greenstone Belt in the Malolotja and Steynsdorp areas. The gold-bearing event distribution is studied using field structural geology associated with a petrological and microstructural analysis. Three major tectonic events have been identified in quartz veins and direct country rocks. The first event (De) created a regional schistosity (Se), probably associated with an early thrusting event. The second event (Df) is related to a large-scale folding, which formed the anticline at Steynsdorp and synform at Malolotja. It resulted from a main E–W direction of shortening and is responsible for the folding of the Se schistosity. It formed a N–S-striking axial planar cleavage (Sf), observed and associated with the emplacement of the main gold-bearing veins. The mineralised system exhibits a complex vein network, in which shallow dipping veins have developed coevally with steep west- and east-dipping veins. A third deformation event (Dl) produced by NE–SW shortening is related to the late barren hydrothermal quartz vein formation. Mineralogically, the veins are filled with abundant quartz, and scarce tourmaline and feldspars. Alteration halos composed of neoformed tourmaline and plagioclase within a talc and white mica matrix developed specifically during the late Dl event. A model of regional deformation giving rise to large-scale folds and quartz vein formation formed in response to E–W and NE–SW directions of shortening globally is proposed and discussed in this paper.
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(This article belongs to the Section Mineral Deposits)
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Analysis and Evaluation of Concentrations of Potentially Toxic Elements in Landfills in the Araucanía Region, Chile
Minerals 2023, 13(8), 1033; https://doi.org/10.3390/min13081033 - 01 Aug 2023
Abstract
This preliminary study focuses on three abandoned sites, located in the communes of Temuco, Villarrica, and Lonquimay, in the Araucanía Region, Chile. Two of the sites were classified as illegal landfills and one was a former landfill. Seventy-three surface samples were taken, of
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This preliminary study focuses on three abandoned sites, located in the communes of Temuco, Villarrica, and Lonquimay, in the Araucanía Region, Chile. Two of the sites were classified as illegal landfills and one was a former landfill. Seventy-three surface samples were taken, of which 32 were from site S1, 20 were from site S2, and 21 were from site S3. The objectives of this study were (1) to establish the background values of trace metals present in soils through different statistical methods, (2) to determine the level of contamination and possible ecological risks in soils, and (3) to assess the health risk posed to children and adults from potentially hazardous elements (As, Ba, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, and Zn). The data analyzed belong to a report presented by Chile’s National Environmental Centre (CENMA). An evaluation was carried out through a multivariate statistical analysis to determine the type of origin and association of the trace elements, and spatial distribution maps were generated to establish the behavior of the contents of heavy metals present in the sites studied. The background values for sites S1, S2, and S3 were obtained by the median + 2MADdian absolute deviation) method. These values varied in the range of 14,702–41,785 mg kg−1 for Al, 0.83–8.9 mg kg−1 for As, 29.2–77.2 mg kg−1 for B, 59.2–143 mg kg−1 for Ba, 10.1–22.8 mg kg−1 for Cd, 18.4–51.2 mg kg−1 for Co, 12.3–38.0 mg kg−1 for Cr, 47.8–76.6 mg kg−1 for Cu, 36,230–64,274 mg kg−1 for Fe, 0.02–0.05 mg kg−1 for Hg, 482–4396 mg kg−1 for Mn, 16.7–19.3 mg kg−1 for Ni, 1.0–17.6 mg kg−1 for Pb, 1.4–28.2 mg kg−1 for Se, 108–258 mg kg−1 for V, and 68.1–145 mg kg−1 for Zn. In terms of ecological risk, the geoaccumulation index (Igeo), enrichment factor (EF), and contamination factor (Cf) values for As and Se at site S1, As at S2, and Pb with As at S3 were the main elements indicating the highest contamination levels, as well as a higher number of samples with contaminated content. The Potential Ecological Risk Index (PERI) revealed that on average, there was a moderate ecological risk for S1 and S2 and a considerable ecological risk for S3; the main contributions were generated by As and Hg in S1 and S2, while, in S3, they were produced by Pb and As. In terms of the risk to human health, the risk was higher in children than in adults, with the ingestion route as the main source of risk. For adults, it was found that there was no likelihood that they would develop any adverse non-carcinogenic or carcinogenic health effects. In contrast, children were found to be more likely to sustain adverse health effects. Regarding the non-carcinogenic risk to children, the Co and As samples at S1, S2, and S3, and the Pb at site S3 showed values exceeding the non-carcinogenic-risk limit. Regarding the carcinogenic risk, all three sites studied had Cd samples that indicated a likelihood of children developing cancer from this heavy metal.
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(This article belongs to the Special Issue Concentration and Distribution of Heavy Metals in Soils, Volume II)
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Jurassic Uranium-Thorium Deposit of Peralkaline Granitic Rocks, Bokan Mountain, Prince of Wales Island, Southeastern Alaska
Minerals 2023, 13(8), 1032; https://doi.org/10.3390/min13081032 - 31 Jul 2023
Abstract
The Lower Jurassic (ca. 177 Ma) Bokan Mountain granitic complex, located on southern Prince of Wales Island, southernmost Alaska hosts a high-grade uranium-thorium deposit with past production. The complex is a circular body (~3 km in diameter) which intruded Paleozoic granitoids as well
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The Lower Jurassic (ca. 177 Ma) Bokan Mountain granitic complex, located on southern Prince of Wales Island, southernmost Alaska hosts a high-grade uranium-thorium deposit with past production. The complex is a circular body (~3 km in diameter) which intruded Paleozoic granitoids as well as metasedimentary and metavolcanic rocks of the Alexander Terrane of the North American Cordillera. This shallow seated intrusion, which is composed of fractionated peralkaline granites, is a zoned body with a dominant core of arfvedsonite granite and a rim of aegirine granite. All the rock-forming minerals typically record a two-stage growth history and aegirine and arfvedsonite were the last major phases to crystallize from the magma. Both arfvedsonite and aegirine granites have overlapping compositions. The rocks have high contents of rare earth elements, Th, U and high field strength elements (Zr, Nb, Hf and Ta) and low contents of Sr, Ba, Eu and Ti, typical of peralkaline granites. The complex hosts structurally controlled rare metal mineralization, which is associated with the late-stage of magma evolution and hydrothermal fluids. Fluorine complexing played a role during the transportation of rare metals in hydrothermal fluids. The U-Th deposit, which occurs at the margin of the aegirine granite zone, includes structurally controlled shear zone-hosted lenses and irregularly shaped pipe-like orebodies. U-Th mineralization is associated with desilicified and albitized granitic rocks and includes mainly uranothorite and uraninite. These minerals mostly form small ovoids in veinlets typically 0.1 to 1 mm wide. The mine produced about 77,000 t of ore at a grade of ~0.76% U3O8 and 3% of ThO2. The parent magma of the pluton was likely derived from a metasomatized lithospheric source (mantle or lower crust), which was enriched by subduction related processes during Paleozoic time.
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(This article belongs to the Section Mineral Deposits)
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Open AccessReview
Advances in Analytical Techniques and Applications in Exploration, Mining, Extraction, and Metallurgical Studies of Rare Earth Elements
by
Minerals 2023, 13(8), 1031; https://doi.org/10.3390/min13081031 - 31 Jul 2023
Abstract
The use of analytical techniques is important and critical in all areas related to REE, such as basic fundamental research, exploration, mining, extraction, and metallurgical activities at different stages by different industries. At every stage of these activities, rock, ore, minerals, and other
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The use of analytical techniques is important and critical in all areas related to REE, such as basic fundamental research, exploration, mining, extraction, and metallurgical activities at different stages by different industries. At every stage of these activities, rock, ore, minerals, and other related materials have to be analyzed for their REE contents in terms of elemental, isotopic, and mineralogical concentrations using different analytical techniques. Spectacular developments have taken place in the area of analytical instrumentation during the last four decades, with some of them having shrunk in size and become handheld. Among laboratory-based techniques, F-AAS, GF-AAS, ICP-OES, and MP-AES have become very popular. Because of high sensitivity, fewer interference effects, and ease of use, ICP-MS techniques, such as quadrupole ICP-MS, ICP-MS/MS, ICP-TOF-MS, MH-ICP-MS, HR-ICP-MS, and MC-ICP-MS, with both solution nebulization as well as direct solid analysis using laser ablation sample introduction methods, have become more popular for REE analysis. For direct analysis of solids, INAA, XRF, and LIBS techniques, as well as LA-based ICP-MS techniques, are being extensively utilized. The LIBS technique in particular requires little to no sample preparation. TIMS, SIMS, and SHRIMP techniques are being used for isotopic as well as dating REE depots. Portable analytical techniques, such as pXRF, pLIBS, and Raman spectrometers are able to perform in situ analysis even in the field, helping to make fast decisions during exploration studies. At present, hyperspectral remote sensing techniques including handheld, drone, and satellite-based techniques have become very popular in REE exploration studies because of their ability to cover larger areas in a limited time and, thus, became very cost-effective. Deployment of microanalytical devices/sensors mounted in remotely operated vehicles (ROV) is being successfully utilized in detecting REE-rich deposits in the deep oceans. Providing updated in-depth information on all these important aspects with suitable examples, especially from the point of view of REE research studies is the focal point of this review article.
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(This article belongs to the Special Issue Rare Earth Elements: Occurrence, Exploration, Alternate Resources, Extraction Techniques, Chemical Characterization and Recycling)
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