Abundant Mineral Research Articles

Natural peloids originating from subsea depths of 200 m in the hupo basin, South Korea: physicochemical properties for potential pelotherapy applications

The present study firstly reports surface sediment from the subsea depth of 200 m as a potential natural peloid. The fine-silt sediment exhibited a consistent clay mineral composition dominated by illite, chlorite, kaolinite, and diatomite. The most abundant clay mineral was illite/mica, with other minerals loosely packed in a face-to-face orientation. The thermal conductivity, specific heat capacity, and cation-exchange capacity of the sediment were in the range 0.855–0.885 W/m K, 2.718–2.821 J/g °C, and 23.06–32.96 cmol/kg, respectively. The concentrations of most toxic elements in the sediment were considerably lower than the limits set by domestic cosmetic regulations and other international standards. The analyzed samples exhibited similar properties to those of previously reported peloids, thus making them suitable for use in the field of pelotherapy; furthermore, the consistency in data across a wide peloid-distribution area is expected to enable economically viable mining. Future investigations should aim to to evaluate the long-term effects on the skin, the bioavailability of potentially hazardous substances, and the therapeutic efficacy for various skin conditions.

Discrimination of tectonic provinces using zircon U-Pb ages from bedrock and detrital samples in the northern Andes

Abstract The northern Andes of southern Colombia contain a rich geologic history recorded by Proterozoic to Cenozoic metamorphic, igneous, and sedimentary rocks. The region plays a pivotal role in understanding the evolution of topography in northwestern South America and the development of large river systems, such as the Amazon, Orinoco, and Magdalena rivers. However, understanding of the basement framework has been hindered by challenging access, security concerns, tropical climate, and outcrop scarcity. Further, an insufficient geochronologic characterization of Andean basement complicates provenance interpretations of adjacent basins and restricts understanding of the paleogeographic evolution of southern Colombia. To address these issues, this paper presents a zircon U-Pb geochronological dataset derived for 24 bedrock samples and 19 modern river samples. The zircon U-Pb results reveal that the Eastern Cordillera of southern Colombia is underlain by basement rocks that originated in various tectonic events since ca. 1.5 Ga, including the accretion of discrete terranes. The oldest rocks, found in the Garzon Massif, are high-grade metamorphic rocks with contrasting Proterozoic protolith crystallization ages. Whereas the SW part of the massif formed during the Putumayo Orogeny (ca. 1.2–0.9 Ga), we report orthogneisses for the NE segment with protoliths formed at ca. 1.5 Ga, representing the NW continuation of the Rio Negro Jurena province of the Amazonian Craton. In contrast, crystalline rocks of the Central Cordillera primarily consist of Permian–Triassic (ca. 270–250 Ma) and Jurassic–Cretaceous (ca. 180–130 Ma) igneous rocks formed in a magmatic arc. In southernmost Colombia, the Putumayo Mountains mainly consist of Jurassic–Cretaceous (180–130 Ma) plutonic and volcanic rocks. Furthermore, we analyzed the heavy mineral abundances in modern river sands in southern Colombia (spanning 1°N–5°N) and found that key minerals such as garnet and epidote can be utilized to trace high-grade metamorphic and igneous lithologies, respectively, in the river catchments. The differentiation of basement ages for separate tectonic provinces, combined with heavy mineral abundances in modern sands, can serve as unique fingerprints in provenance analyses to trace the topographic and exhumational evolution of different Andean regions through time.

Quantifying the Pore Heterogeneity of Alkaline Lake Shale during Hydrous Pyrolysis by Using the Multifractal Method

Distinguishing itself from marine shale formations, alkaline lake shale, as a significant hydrocarbon source rock and petroleum reservoir, exhibits distinct multifractal characteristics and evolutionary patterns. This study employs a combination of hydrous pyrolysis experimentation, nitrogen adsorption analysis, and multifractal theory to investigate the factors influencing pore heterogeneity and multifractal dimension during the maturation process of shale with abundant rich alkaline minerals. Utilizing partial least squares (PLS) analysis, a comparative examination is conducted, elucidating the disparate influence of mineralogical composition on their respective multifractal dimensions. The findings reveal a dynamic evolution of pore characteristics throughout the maturation process of alkaline lake shale, delineated into three distinct stages. Initially, in Stage 1 (200 °C to 300 °C), both ΔD and H demonstrate an incremental trend, rising from 1.2699 to 1.3 and from 0.8615 to 0.8636, respectively. Subsequently, in Stages 2 and 3, fluctuations are observed in the values of ΔD and D, while the H value undergoes a pronounced decline to 0.85. Additionally, the parameter D1 exhibits a diminishing trajectory across all stages, decreasing from 0.859 to 0.829, indicative of evolving pore structure characteristics throughout the maturation process. The distinct alkaline environment and mineral composition of alkaline lake shale engender disparate diagenetic effects during its maturation process compared with other shale varieties. Consequently, this disparity results in contrasting evolutionary trajectories in pore heterogeneity and multifractal characteristics. Specifically, multifractal characteristics of alkaline lake shale are primarily influenced by quartz, potassium feldspar, clay minerals, and alkaline minerals.

Spatial variability of clay minerals in a semi-arid region of Turkiye

Clay minerals are the source of many chemical and physical properties that influence the provision of soil-based ecosystem services. This study aimed to identify the most significant soil characteristics contributing to the spatial variability of clay minerals in a semi-arid region of Turkiye. Additionally, the study assessed the predictive capabilities of Classification and Regression Tree (CART), Random Forest Regression (RF) and eXtreme Gradient Boosting Regression (XGBoost) in estimating soil clay mineral content. Smectite+vermiculite (SMVR) was the most abundant clay mineral in the study area, followed by illite and kaolinite. Hyperparameter tuning significantly improved model accuracy, with root mean square error (RMSE) reductions ranging from 2.53% to 97.3%. The machine learning algorithms demonstrated varying performances in spatial prediction accuracy. The RF model achieved the lowest RMSE (8.587%) and the highest R2 values (0.796) for predicting SMVR. The XGBoost outperformed other models for kaolinite (RMSE: 4.814%, R2:0.713) and illite (RMSE:7.368%, R2:0.613). Exchangeable cations, particularly magnesium (Mg) and calcium (Ca), were identified as crucial factors influencing the spatial distribution of clay minerals. Among these, M concentration had the strongest influence on predicting both SMVR (38.1%) and illite (26.3%). Conversely, for kaolinite prediction, Ca concentration played the most significant role (38.7%), followed by Mg (19.93%). In conclusion, this study demonstrates the effectiveness of machine learning models, particularly XGBoost which achieved the lowest RMSE for all clay minerals investigated. These models offer a valuable tool for predicting clay mineral content in the Kazova Plain. The findings highlight the importance of parent material, weathering processes, and specific soil properties, such as exchangeable cations, in shaping clay mineral distribution. This knowledge not only contributes to a deeper understanding of soil formation in semi-arid environments but also practical applications. For instance, by predicting the abundance of SVMR, known for its high cation exchange capacity land managers can develop targeted strategies for optimizing fertilizer application in the Kazova Plain.

U-Pb dating of bastnäsite from the Vuoriyarvi massif: An example application for assessing the REE potential of carbonatite-related deposits

The Vuoriyarvi massif is a Devonian multistage alkaline-ultrabasic carbonatite complex within the Kola alkaline province. Dolomite carbonatites of the Vuoriyarvi massif contain abundant rare-earth mineralization mainly represented by ancylite-(Ce) and bastnäsite-(Ce). Ancylite was previously shown to have probably formed in the Devonian (ca. 365 Ma) during an early postmagmatic overprint. Previous geological observations have revealed a much later crystallization of bastnäsite but have not been able to specify the exact age of the mineralization. The in situ U-Pb dating of bastnäsite allowed us to constrain its genesis. Bastnäsite for this study was extracted from two varieties of dolomite carbonatite breccias cemented by (1) quartz-bastnäsite and (2) strontianite aggregates (hereafter bastnäsite-rich and strontianite-rich carbonatites – BRC and SRC, respectively). The obtained age estimations (237.7 ± 9.8 Ma and 239.9 ± 4.1 Ma, respectively) indicate that both studied rocks were formed during a single event. The revealed age difference (∼125 Ma) excludes the genetic link between the bastnäsite origin and regional alkaline magmatism, pointing out an additional source for the Vuoriyarvi bastnäsite-bearing rocks. Moreover, the obtained U-Pb ages provide strong evidence that a Triassic event is responsible for the occurrence of bastnäsite mineralization due to hydrothermal REE redistribution from the Devonian ancylite-rich carbonatites. Most of the REEs released during this process via dissolution of ancylite were precipitated in situ as bastnäsite, while strontium was transported and incorporated into strontianite. The Pb isotopic characteristics of bastnäsite (206Pb/204Pb = 18.1 ± 0.1, 207Pb/204Pb = 15.3 ± 0.1, and 207Pb/206Pb = 0.84 ± 0.01) are most probably inherited from the Devonian host rocks of the Vuoriyarvi massif involved in the Triassic overprint. Isotopic signatures of Pb, Sr, and Nd show that the depleted mantle and lower crust played the leading role in formation of the Vuoriyarvi alkaline complex. Taken together, the results of the present study negate the supergene origin of the Vuoriyarvi bastnäsite, implying that the bastnäsite mineralization is not confined to near-surface layers and, therefore, may be dispersed more broadly throughout the complex. These findings raise the question on underestimation of the probable REE reserves and lay the groundwork for a reassessment of the economic potential of the Vuoriyarvi complex.

Hydrogen incorporation mechanism in the lower-mantle bridgmanite

Abstract Bridgmanite, the most abundant mineral in the lower mantle, can play an essential role in deep-Earth hydrogen storage and circulation processes. To better evaluate the hydrogen storage capacity and its substitution mechanism in bridgmanite occurring in nature, we have synthesized high-quality single-crystal bridgmanite with a composition of (Mg0.88Fe0.052+Fe0.053+Al0.03)(Si0.88Al0.11H0.01)O3 at nearly water-saturated environments relevant to topmost lower mantle pressure and temperature conditions. The crystallographic site position of hydrogen in the synthetic (Fe,Al)-bearing bridgmanite is evaluated by a time-of-flight single-crystal neutron diffraction scheme, together with supporting evidence from polarized infrared spectroscopy. Analysis of the results shows that the primary hydrogen site has an OH bond direction nearly parallel to the crystallographic b axis of the orthorhombic bridgmanite lattice, where hydrogen is located along the line between two oxygen anions to form a straight geometry of covalent and hydrogen bonds. Our modeled results show that hydrogen is incorporated into the crystal structure via coupled substitution of Al3+ and H+ simultaneously exchanging for Si4+, which does not require any cation vacancy. The concentration of hydrogen evaluated by secondary-ion mass spectrometry and neutron diffraction is ~0.1 wt% H2O and consistent with each other, showing that neutron diffraction can be an alternative quantitative means for the characterization of trace amounts of hydrogen and its site occupancy in nominally anhydrous minerals.

Formation of Topaz-Greisen by a Boiling Fluid: A Case Study from the Sn-W-Li Deposit, Zinnwald/Cínovec

Abstract Zinnwald/Cínovec is one of the largest Li-Sn-W greisen deposits in Europe. Greisens in general are important hosts for many major ore deposits of several high-tech elements—most prominently Sn, W, and Li. However, the mechanisms of greisenization in relationship to ore formation are still not well understood, especially for the important case of fluoride-rich greisen. Here, we investigate the sequence and formation mechanism of the topaz-greisen in the Zinnwald/Cínovec deposit. Based on the mineral abundances, the alteration profile can be divided into four distinct zones: (1) rhyolite, (2) albitite, (3) low-degree greisen, and (4) high-degree greisen. In the greisen zones, almost all the feldspar has been replaced by topaz (up to 12 vol %) + quartz (up to 78 vol %), and the abundance of mica gradually decreases from 11 to 3 vol % with increasing degree of greisenization. Mass balance calculations indicate a net influx of F and silica during greisenization. Our observations are best explained by a two-stage greisenization process involving phase separation by boiling in the pore space of the sample: first an acidic HF-rich phase, likely a vapor, reacted with feldspar to form topaz and quartz in a dissolution-precipitation reaction. This reaction created substantial transient porosity, which was subsequently sealed by the precipitation of quartz and fluorite from a boiling liquid. We interpret the vapor and liquid as emerging from a common supercritical aqueous parental fluid. The characteristic sequence of creation of pore space by a vapor and the subsequent reduction of porosity by precipitation from the associated boiling liquid constrain the conditions and time available for ore formation. This study evaluates the mechanism of topaz greisenization and the controls on porosity evolution, which are crucial to ore element redistribution.

The Existence of Macroalgae in Indonesia: Unlocking the Nutritive Potential for Sustainable Beef Production

Abstract Assessment of the existence of macroalgae and revealing the chemical composition to investigate the potential usage for feed to support sustainable beef production has been conducted in Indonesian prominent livestock production area specifically Lombok, Bali, Yogyakarta, Lampung and Bengkulu. These regions host numerous seaweed production centres, while others hold the capacity to develop into seaweed cultivation zones. To assess the existence, utilisation, and accessibility of macroalgae in each region, observations and interviews were conducted. Subsequently, dominant macroalgae species were sampled and subjected to proximate analysis to determine their nutritional profiles. The results showed that the dominant macroalgae observed included red algae (Rhodophyta) like Eucheuma sp., Gracilaria sp., and Acanthophora sp., green algae (Chlorophyta) such as Ulva sp. and Caulerpa sp., and the brown alga (Phaeophyta) Sargassum sp. The dominant macroalgae found in all five observation sites with high abundance were Sargassum sp., Gracilaria sp., and Eucheuma cottonii. Ulva sp. and Eucheuma spinosum were present at four sites, while Acanthophora sp. and Caulerpa sp. were found at three sites. The dry matter content of the macroalgae ranged from 9.92% to 17.01%, with the highest values observed in the Eucheuma group (14.11%-17.01%). This was followed by Sargassum sp. (12.55 ± 2.40%), Ulva sp. (12.28 ± 2.33%), and Gracilaria sp. (11.09 ± 3.79%). Caulerpa sp. exhibited the lowest dry matter content (9.92 ± 1.29%). The crude protein (CP) content varied both within and between groups of algae species and observation sites. Gracilaria sp. exhibited the highest CP content (13.55 ± 0.16%), followed by Caulerpa sp. (11.87 ± 2.22%), Sargassum sp. (8.98 ± 0.42%), and Ulva sp. (6.98 ± 0.94%). The mineral content of the macroalgae was noticeably high, which is reflected in the low organic matter content. Ulva sp. had the highest organic matter content (80.17%), followed by Sargassum sp. (70.55%), Gracilaria sp. (66.53%), Caulerpa sp. (47.61%), and Eucheuma cottonii (43.50%). The readily available seaweed in this study tend to exhibit moderate to high protein and mineral content, making it a promising partial replacement or supplement for conventional feed, potentially contributing to sustainable beef production. Gracilaria sp., the most readily available seaweed, high in nutrient content with the potential to partially replace conventional feed protein sources. Its abundance of vitamins and minerals may enrich the overall value of the feed.

Microtextural evidence for the recrystallization of opal-A to quartz in epithermal veins: A case study from the McLaughlin deposit, California

High-grade ores in low-sulfidation epithermal deposits commonly consist of banded veins containing quartz as the most abundant gangue mineral. Previous studies suggested that at least some of the quartz has formed as a product of recrystallization from a noncrystalline silica precursor. Detailed petrographic studies confirm that high-grade veins from the <2.2 Ma McLaughlin deposit in California were originally entirely composed of opal-AG. The noncrystalline silica is isotropic in crossed-polarized light and consists of compacted microspheres that are up to several micrometers in size. In many bands of the high-grade veins, the thermodynamically unstable opal-AG has matured to quartz. The recrystallization of the noncrystalline silica resulted in the development of quartz and ore textures that mask the original conditions of vein formation. Incipient recrystallization of the opal-AG caused the formation of lepispheres consisting of opal-CT as well as the development of concentrically banded silica spheres. Continued maturation led to the growth of elongated quartz crystals or complexly shaped quartz aggregates in the cores of the concentrically banded silica spheres. Amalgamation of quartz crystals caused the development of mosaic quartz or flamboyant quartz. Ripening produced large prismatic quartz crystals, which are characterized by zones of feathery appearance. Fluid inclusions within the quartz formed through recrystallization are typically highly irregular in shape and show inconsistent liquid-to-vapor volumetric proportions, but assemblages with consistent ratios are also present. Bands rich in fluid inclusions occurring along former recrystallization fronts in prismatic quartz crystals resemble growth zones in zonal quartz. Recrystallization of the silica matrix resulted in grain coarsening of the ore minerals and encapsulation of ore minerals by quartz. In areas where recrystallization of the noncrystalline silica proceeded to completeness, the quartz textures could be easily misinterpreted to indicate that quartz growth occurred in open space with the ore minerals infilling vug spaces. Correct recognition of recrystallization textures has significant implications for paragenetic investigations on vein material from epithermal deposits as well as the design of fluid inclusion studies.

Enhancing drought tolerance in broccoli (Brassica oleracea L.) through melatonin application: Physiological and biochemical insights into growth, photosynthesis, and antioxidant defense mechanisms

Broccoli is a well-known and high-value vegetable crop for its abundance of antioxidants and minerals. Despite its popularity, its production faces significant challenges from various abiotic stressors, particularly drought stress. Melatonin a multifunctional molecule within plants modulates environmental stresses including drought stress. Therefore, the current study aimed to evaluate the effect of melatonin application (0 and 100 μM) on broccoli under 100% field capacity (FC) (well-watered) and drought stress (50% field capacity). Foliar application of melatonin helped overcome drought-induced losses and enhanced plant height (23.72%), root length (43.47%), total chlorophyll contents (46%), carotenoids (60%) and yield (34.23%), glycine betaine (GB) (77.7%), whereas reducing the oxidative activities of hydrogen peroxide (H2O2) (20%) and leaf water potential (LWP) (33.35%) in broccoli plants. Antioxidant activities, i.e., superoxide dismutase (SOD), peroxide (POD), catalase (CAT), and ascorbate (APX) were further enhanced under melatonin treatment with 28.53%, 26.10%, 35.26%, and 33.33% respectively. Melatonin application significantly increased gas exchange characteristics by increasing stomatal conductance. Pearson correlation matrix and biplot were developed for the determination of trait association and treatment performance. Exogenous melatonin application decreased the oxidative damage brought on by the drought and increased the yield of broccoli.

Updating the alluvial mapping of the middle Loire catchment: Predictive geomorphology approach and mineralogical characterization of the deposits

This study aims to provide a full synthesis of recent work on the fluvial terraces of the middle section of the Loire River, between its exit from the “Massif Central” montane area and its entry into the Touraine region, with the aim of better understanding of the evolution of the river during the Pleistocene period.New fieldwork and topographic analyses (including a predictive geomorphology approach) permit updating the spatial extent and geometry of the different Quaternary alluvial sedimentary formations in this area. In addition, new analytical data were acquired both by X-ray diffraction (XRD) on heavy minerals and by gamma spectrometry measurements on alluvial sandy sediments. These analyses allow us to characterize and distinguish the alluvial formations.This work has identified three distinct periods in the history of the Loire: the oldest, corresponding to the deposition of sediments characterised by an abundance of metamorphic minerals, originating from the Massif Central; an intermediate period, corresponding to the deposition of the high terraces of the Loire system, not characterised by mineralogical analyses but by the approach of the predicted geomorphology showing different terrace geometries; lastly, a recent period comprising the low and medium altitude terraces, characterised by an abundance of volcanic minerals also originating from the Massif Central.

Caveolin-dependent endocytosis regulates arterial calcification

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): SFB219 Introduction Patients with chronic kidney disease (CKD) have a significantly elevated cardiovascular risk, which is primarily due to premature vascular aging with arterial calcification - a substantial public health burden. Calcifying extracellular vesicles (EVs) are required for the onset and progression of calcification. Endocytosis and exocytosis are important for EV genesis and cargo loading, thus controlling EV release and propensities. Purpose We aim to investigate endocytosis, endosomal ripening, and exocytosis as critical mechanisms of EV-dependent mineralization. Methods and Results First, we characterized EVs from calcifying vascular smooth muscle cells (SMCs) compared to control SMCs. Western blot analysis revealed an increase in tissue nonspecific alkaline phosphatase (TNAP) among calcifying EVs but not in flotillin abundance. When compared to control EVs, calcifying EVs showed higher TNAP activity. Flow cytometry and a turbidity assay were then used to evaluate EV mineral cargo and aggregation potential. Compared to the control, EVs produced from SMCs cultivated under calcifying conditions had 5-fold more mineral-positive EVs (p=0.004) and a 3-fold higher nucleation potential (p&amp;lt;0.001). Next, endocytosis was blocked by targeting Dynamin-1 and –2, which inhibited caveolin- and clathrin-dependent endocytosis (Dynasore hydrate), or targeting clathrin-terminal domain, which inhibited solely clathrin-dependent endocytosis (Pitstop 2). Dynasore reduced matrix mineralization dose-dependently and lowered mineral-positive EVs by 18%, whereas Pitstop 2 had no effect, suggesting a role of caveolin-dependent endocytosis in EV-mediated calcification. Indeed, Cav-1 silencing inhibited matrix mineralization and Cav-1 protein was more abundant in calcifying EVs than in control EVs. Dynasore and Pitstop-2 did not affect the EV number measured by nanoparticle tracking analysis. Inhibition of endosomal ripening by Rab7 inhibition did not affect SMC calcification. Exocytosis was inhibited by Rab27a inhibition, which reduced mineral deposition (-32%, p=0.017) without affecting EV mineral or EV quantity. Conclusion EVs released from calcifying SMCs showed a higher abundance of mineral and TNAP proteins, suggesting a role in mineral transport and deposition. Our data suggest that caveolin-dependent endocytosis is essential in EV-mediated SMC calcification. Mineral cargo in EVs is independent of Rab7 and Rab27a pathways.

Influence of Mineralogy and Mineralogy Approach to Optimize Processing: A Case Study of Tin–Copper Polymetallic Ore

Tin-Copper polymetallic ore is a type of typical ore that cassiterite is closely associated with sulfide minerals. In mineral processing of tin–copper polymetallic ore, flotation is generally used to recover valuable sulfide minerals, while gravity separation is used to recover cassiterite. A mine in Yunnan, China, uses the traditional “flotation–gravity separation” process to recover copper and tin but faces several problems during processing, such as an insufficient copper grade in Cu concentrate, a much higher grade of As in S concentrate, and a grade of S in Sn concentrate that exceeds the standard. A process mineralogy study was conducted, with a focus on Cu–S mixed concentrate, S concentrate, and Sn rough concentrate. It was determined that the main cause of these problems is not the liberation or size distribution of valuable minerals but the superstructure of pyrrhotite, which represents one of the most abundant minerals in the products. Based on EMPA, SEM-EDS, and XRD data, both monoclinic pyrrhotite and hexagonal pyrrhotite occurred in all samples. The abundance of different superstructures of pyrrhotite in one sample was determined by means of particle extraction and area calculation from microscopic images, and the distribution characteristics of monoclinic pyrrhotite and hexagonal pyrrhotite in the whole process were clarified. This process mineralogy study indicates that the strong magnetic hexagonal pyrrhotite mainly affects the copper recovery during flotation, and the hexagonal pyrrhotite mainly affects the recovery of cassiterite during gravity separation. Strong magnetic monoclinic pyrrhotite and weak magnetic hexagonal pyrrhotite should be fully considered in the optimization of mineral processing, and the magnetic separation of pyrrhotite should be adopted to optimize the overall environment of copper flotation and tin gravity separation.

Geological and Geochemical Characterization of Variscan Pegmatites in the Sidi Bou Othmane District, Central Jebilet Province, Morocco

The Sidi Bou Othmane (SBO) pegmatite district is situated in the Central Jebilet massif, Western Meseta domain, Morocco. The SBO district is hosted essentially in a volcano-sedimentary series composed of Late-Devonian Sarhlef shales. Pegmatite bodies crop out as dykes, which are oriented from N-S to E-W and are generally variably deformed with ductile and/or brittle structures with ante, syn- or post-kinematic criteria. Petrographic observations of pegmatite dykes show that feldspars (i.e., albite, microcline) are the most abundant mineral phases, followed by quartz and micas, with tourmaline and accessory minerals such as garnet, and zircon also featuring heavily, as well as secondary minerals such as clinochlore, sericite, and illite. The geochemical study of the SBO pegmatites indicates that they have mainly S-type granitic compositions, which are peraluminous granites with calc-alkalic affinities. The study of trace elements indicates that SBO pegmatites were formed in post-orogenic syn-collision context during the Variscan orogeny by the partial melting of argilliferous sediment. They can be ascribed to the muscovite-bearing pegmatite; moreover, they have good potential regarding ceramics. They also contain minerals, such as feldspar, which have been recently assessed as critical raw materials by the European Union.

Insights into the Crystallinity-Dependent Photochemical Productions of Reactive Oxygen Species from Iron Minerals.

Iron minerals are widespread in earth's surface water and soil. Recent studies have revealed that under sunlight irradiation, iron minerals are photoactive on producing reactive oxygen species (ROS), a group of key species in regulating elemental cycling, microbe inactivation, and pollutant degradation. In nature, iron minerals exhibit varying crystallinity under different hydrogeological conditions. While crystallinity is a known key parameter determining the overall activity of iron minerals, the impact of iron mineral crystallinity on photochemical ROS production remains unknown. Here, we assessed the photochemical ROS production from ferrihydrites with different degrees of crystallinity. All examined ferrihydrites demonstrated photoactivity under irradiation, resulting in the generation of hydrogen peroxide (H2O2) and hydroxyl radical (•OH). The photochemical ROS production from ferrihydrites increased with decreasing ferrihydrite crystallinity. The crystallinity-dependent photochemical •OH production was primarily attributed to conduction band reduction reactions, with the reduction of O2 by conduction band electrons being the rate-limiting key process. Conversely, the crystallinity of iron minerals had a negligible influence on photon-to-electron conversion efficiency or surface Fenton-like activity. The difference in ROS productions led to a discrepant degradation efficiency of organic pollutants on iron mineral surfaces. Our study provides valuable insights into the crystallinity-dependent ROS productions from iron minerals in natural systems, emphasizing the significance of iron mineral photochemistry in natural sites with abundant lower-crystallinity iron minerals such as wetland water and surface soils.

Mineral extraction and governance in the Nigerian Mining Industry: An examination of regulatory conflicts amongst Nigeria’s three tiers of government

Nigeria’s abundant mineral potentials can be harnessed to significantly contribute to her socio-economic development if the regulatory framework of the Nigerian Mining Industry (NMI) is properly articulated and implemented, devoid of the regulatory conflicts that have been observed amongst various regulatory and government entities. This article analyses a 2019 – 2020 study undertaken by the Ministry of Mines and Steel development in the Federal Capital Territory and 17 out of the 36 States of the Federal Republic of Nigeria which exposed mining sector-related regulatory conflicts amongst the Federal, State and Local Governments and their Ministries, Departments, and Agencies (MDAs). The study also revealed that, despite certain extant Constitutional and statutory instruments vesting the control of minerals and mining activities on the Federal Government and its Ministry of Mines and Steel Development, the implementation of other national and subnational statutory instruments has generated regulatory conflicts and controversial interferences in the governance of mineral resources in the country. This development has led to adverse political and socio-economic implications and outcomes. Thus, after an in-depth consideration of these regulatory conflicts and its implications, the article recommends, among other salient solutions, the amendment and/or repeal of all applicable mining statutes and regulations to remove these regulatory conflicts, and this will better position the NMI on the path to restoration and ultimately surpassing its glorious past.

Application of geological and short wavelength infrared (SWIR) spectroscopy mapping in the Mailong gold deposit, East Kunlun: Implications for exploration targeting

Widespread regolith cover makes it difficult to identify the anomalous size of their mineralogical or geochemical footprint at the surface in gold exploration. Short wavelength infrared (SWIR) spectroscopy with effective identification of clays and other hydrous minerals shows potential application in gold exploration. The detailed geological and short wavelength infrared (SWIR) spectroscopy mapping was conducted in the newly-discovered orogenic-type Mailong gold deposit (13.06 t @ 6.29 g/t Au), East Kunlun, to determine alteration stage and mineral assemblages and discuss the potential values of SWIR spectral in gold exploration.In the Mailong area, magmatic rocks consist of granodiorite, biotite granodiorite, plagiogranite and mafic dikes, and the gold mineralization shows a close spatial and temporal relationship with mafic dikes. The earliest chloritization (chlorite-quartz) is widely distributed in granodiorite, biotite granodiorite and plagiogranite. The following potassic alteration (hydrothermal K-feldspar and quartz) is developed along high-angle fault/fracture, which cut through granodiorite, biotite granodiorite and plagiogranite. The subsequent sulfide alteration (chlorite-muscovite-sulfide-carbonate) overprints the former potassic and chloritization alteration, and shows spatial association with mafic dikes. Native gold occurs in fracture arsenopyrite or associated with minerals such as pyrite, and chalcopyrite during the early sulfide stage. Supergene alteration is characterized by limonite and malachite. At Mailong, the SWIR data indicate that the most abundant alteration minerals (chlorite, white micas and ankerite) mainly occurred in the northern area. White mica Al-OH absorption occurs at longer wavelengths (Pos2200 = 2202.5 ∼ 2203 nm) and higher Illite crystallinity (IC = 1.2 ∼ 3.1) probably reflecting a higher temperature and pH conduit at the bottom of ZK0001 and ZK0801. The sharp shift of IC values near the bottom reflects the control of fault. This area is also situated at the V-shaped intersections of the three granitic intrusions and structural transection, indicating more of a possible hydrothermal fluid channel than a mineralization center. Low-grade Au mineralization (Au = 0.1 ∼ 0.5 g/t) is mainly distributed within hydrothermal channels with higher Pos2200 (mainly 2022.5 ∼ 2203 nm) and IC values (mainly 1.2 ∼ 3.1), while high-grade Au endowment associated with mafic dikes has low Pos2200 (mainly 2201 ∼ 2202.5 nm) and IC values (mainly 0.43 ∼ 1.2). Meanwhile, an equation of distance = -15*IC + 31 (R2 = 0.47) can be summarized for low-grade orebodies vectoring. Integrating geological mapping and spectral data, target areas for high-grade ore bodies can be outlined using the criteria of white mica, shorter wavelength of Al-OH absorption position (Pos2200 = 2201 ∼ 2202.5 nm), lower IC values (IC = 0.43 ∼ 1.2), and chlorite Fe-OH absorption position Pos2250 (>2247 nm) along with occurrences of mafic dikes. This study demonstrates that utilizing the detailed SWIR identification in conjunction with accurate geological mapping has great potential for greenfield exploration of orogenic gold deposits.

Influence of botanical origin and geographical zones on physicochemical properties, mineral contents and consumer acceptance of honey in Tanzania

Honey offers nutritional and therapeutic benefits to people, hence understanding its quality and consumer preferences is essential for its consumption. In this study, the physicochemical properties, mineral content, and consumer preferences of honey samples from various Tanzanian geographical zones and botanical origins were investigated. Thirty-two honey samples from acacia species and miombo woodland origins were purchased from beekeepers in five zones of Tanzania, and analyzed for those parameters using standard methods. The lake zone acacia samples had significantly (p < 0.05) higher moisture while the northern zone miombo samples had higher acidity than other samples. The lake zone miombo sample had a higher viscosity than other samples. Potassium was the most abundant mineral (380.2 ± 89.30–3488.1 ± 87.17 mg/kg) in honey and all minerals differed significantly (p < 0.05) between botanical origins and geographical zones with miombo samples in all zones having higher values than their acacia counterparts. Furthermore, the eastern zone miombo and lake zone acacia honey were the most acceptable samples by consumers. Therefore, the Tanzanian honey quality and consumer preferences vary significantly with botanical and geographical origins. Nevertheless, despite the variations, quality values were within the national and internal standard bounds, hence the consumption of these honey is encouraged based on their known benefits.

Temperature-dependent dielectric properties of the Korean lunar simulant and ilmenite: Lunar microwave processing potential

There is increasing interest in the potential application of microwave sintering technology in the construction of infrastructure on the Moon. This study aimed to characterize the dielectric properties of in situ lunar materials; this information is critical for an understanding of the interaction of these materials with microwave and in the application of microwave sintering technology. Dielectric properties including the real and imaginary permittivity, dielectric loss tangent, penetration depth, and electrical conductivity of Korean Lunar Simulant (KLS-1) and ilmenite (an abundant lunar mineral) were investigated at microwave frequencies as a function of temperature. X-ray dispersion (XRD) analyses confirmed that the lattice expansion of minerals with increasing temperature was consistent with an increasing trend in permittivity. The dielectric loss tangent of ilmenite was 2–36 times higher than that of KLS-1, depending on temperature, indicating that ilmenite has greater ability to absorb microwave energy, converting it to heat. Ilmenite demonstrated rapid heating to 1000°C within a few minutes on exposure to 1 kW microwave (2.45 GHz) irradiation. This study provides important information relevant to the development of microwave technology for future lunar applications.

Impact of Pyrite Textures Prevalence on Flotation Performance in Mount Isa Copper Orebodies

ABSTRACT Pyrite, the most abundant sulfide mineral in base-metal deposits, presents significant challenges in mineral processing due to its deleterious effects when not properly managed. Its undesirable association with valuable minerals leads to low-quality concentrates, hindering smelting processes. Pyrite’s distinct textures and variable elemental compositions affect its floatability, with complex textures challenging to depress. Moreover, since multiple textures can be present within an orebody, their relative proportion in the ore could affect the overall flotation performance. Therefore, understanding the types of pyrite present, their abundance, and how they affect the flotation behavior of the ore is critical for an efficient depression and possible reclamation of pyrite. At the Mount Isa copper deposit, framboidal or ‘carbonaceous’ pyrite has been an ongoing challenge to the copper concentration operation, reducing the flotation circuit’s efficiency. Previous work by Yenial-Arslan et al. showed that high pyrite recoveries could be strongly linked to the prevalence of fine-grained pyrite. However, samples belonging to the coarse pyrite domain exhibited low natural floatability. This study further investigates the effect of the prevalence of pyrite textures on the flotation performance of copper orebodies at the Mount Isa deposit. The prevalence of pyrite textures was quantified and statistically linked to the natural floatability of pyrite, proving that fine-grained and framboidal pyrite greatly influence pyrite’s overall recovery. Furthermore, various mineral characterization techniques, such as synchrotron X-ray fluorescence microscopy (XFM) analysis, were used to explore how the natural floatability of pyrite was affected.