Search Results (664)

The uptake and translocation of Pb, Cr, Cd, and Zn in tomato plants (Solanum lycopersicum L. Rally) were investigated. Tomato seedlings were grown for five weeks in pots containing 40 L of Hoagland nutrient solution (pH 7) or contaminated nutrient solutions at two concentration levels for each element: Cr (100 and 1000 ng/mL), Zn (100 and 1000 ng/mL), Pb (100 and 500 ng/mL), and Cd (50 and 500 ng/mL). The solutions were replenished weekly to maintain a volume of 40 L (pH 7), and 10 mL samples were collected for elemental analysis. After five weeks, the plants were harvested and separated into roots, stems, leaves, and fruits. These samples underwent microwave-assisted digestion, and the element concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS). The results revealed that the elements were mainly accumulated in the roots, with much lower concentrations determined in the fruits. Pb and Cr accumulated only minimally in fruits, with Pb levels of 0.0009 mg/kg wet weight at LI and 0.003 mg/kg wet weight at LII, and Cr levels of 0.028 mg/kg wet weight at LI and 0.031 mg/kg wet weight at LII. The Pb levels did not exceed the permissible limits set by EC regulations (0.05 mg/kg wet weight). Zn exhibited the highest accumulation in fruits, with 2.17 mg/kg wet weight at LI and 4.8 mg/kg wet weight at LII. By contrast, the Cd concentrations in fruits (0.25 mg/kg wet weight at LI and 1.1 mg/kg wet weight at LII) exceeded the EC regulatory limit of 0.02 mg/kg wet weight. The uptake of other essential elements into the tomato plant remained largely unaffected by the presence of contaminants. These results provide valuable insights into food safety. Laser ablation (LA)-ICP-MS imaging revealed an even distribution of Cd and Zn in the leaves of plants grown in contaminated nutrient solutions. By contrast, Cr and Pb were predominantly localized in the leaf veins and at the leaf apex, suggesting different transport mechanisms for these elements from the roots to the aerial parts of the plant. Full article

The Chaluo granite is situated in the middle section of the Yidun magmatic arc in western Sichuan Province, China. It holds great significance for the study of the geological evolution of the Paleo-Neotethys tectonic belts. The Chaluo granite mainly consists of alkaline feldspar, quartz, and biotite, with a small amount of apatite. LA-ICP-MS zircon U-Pb dating yielded crystallization ages of (87 ± 3) Ma for the Chaluo granite, indicating its formation in the Late Cretaceous. Elemental geochemical testing results showed that the Chaluo granite exhibits I-type granite characteristics. It has undergone significant fractional crystallization processes, with high SiO₂ contents (72.83–76.63 wt%), K (K₂O/Na₂O = 1.33–1.53), Al₂O₃ (Al₂O₃ = 12.24–13.56 wt%, A/CNK = 0.91–1.08), and a high differentiation index (DI = 88.91–92.49). Notably, the MgO contents were low (0.10–0.26 wt%), and there were significant depletions of Nb, Sr, Ti, and Eu, while Rb, Pb, Th, U, Zr, and Hf were significantly enriched. The total rare earth element (REE) contents were relatively low (211–383 ppm), showing significant light REE (LREE) enrichment (LREE/HREE = 4.46–5.57) and a pronounced negative Eu anomaly (δEu = 0.09–0.17). In situ zircon Hf analyses, combined with ²⁰⁶Pb/²³⁸U ages, gave ε_Hf(t) values ranging from −3.8 to 1.72 and two-stage Hf ages (t_DM2) of 875–1160 Ma. Together with the S and Pb isotope compositions of the Chaluo granite, its magma likely originated from the partial melting of Middle–Neoproterozoic sedimentary rocks enriched in biogenic S. The tectonic-setting analysis indicates that the Chaluo granite formed in a post-orogenic intracontinental extensional environment. This environment was triggered by the northward subduction-collision of the Lhasa block, followed by slab break-off and the upwelling of the asthenosphere in the Neo-Tethys orogenic belt. We propose that the Paleo-Tethys tectonic belt was influenced by the Neo-Tethys tectonic activity, at least in the Yidun magmatic arc region during the Late Cretaceous. Full article

The Dulong Sn-polymetallic deposit in Yunnan Province of southwestern China serves as a unique case study for unraveling the evolution of skarn systems and tin mineralization. Four distinct garnet types (Grt I to Grt IV) were classified based on petrographic observations. Compositional analysis reveals a progression from Grt I to Grt III, marked by increasing andradite components, and elevated tin concentrations, peaking at 5039 ppm. These trends suggest crystallization from Sn-enriched magmatic-hydrothermal fluids. In contrast, Grt IV garnet exhibits dominant almandine components and minimal tin content (<2 ppm). Its association with surrounding rocks (schist) further implies its metamorphic origin, distinct from the magmatic origin of the other garnet types. Combined with previously published sulfur and lead isotopic data, as well as trace element compositions of garnet, our study suggests that Laojunshan granites supply substantial ore-forming elements such as S, Pb, W, Sn, In, and Ga. In contrast, elements such as Sc, Y, and Ge are inferred to be predominantly derived from, or buffered by, the surrounding rocks. The geochemical evolution of the garnets highlights the critical role of redox fluctuations and fluid chemistry in controlling tin mineralization. Under neutral-pH fluid conditions, early-stage garnets incorporated significant tin. As the oxygen fugacity of the ore-forming fluid declined, cassiterite precipitation was triggered, leading to tin mineralization. This study reveals the interplay between fluid redox dynamics, garnet compositional changes, and mineral paragenesis in skarn-type tin deposits. Full article

This study provides a detailed geochronological paragenesis of fracture systems from the Upper Jurassic petroleum source formation in NE Iraq, utilizing U-Pb dating, integrated with microprobe analyses and petrographic studies. Five fracturing stages are recognized (FI–FV), indicating significant tectonic and temperature changes from the Late Jurassic to Pliocene times (approximately 5.2–5.5 Ma). The burial history curve shows continuous subsidence events, starting with initial burial of the Barsarin Formation reaching depths of 1000–1200 m by 110 Ma, this depth interval coincides with the first fracturing stage (FI). The buffered system of FI by pristine facies and geometrical cross-cutting of FI with early stylolite formation show a prior formation of stylolite. Subsequent fracturing stages FII (28.6 ± 2 Ma, Oligocene) and FIII (19.83 ± 0.43 Ma, Early Miocene) were contemporaneous with tectonic deformation phases and hydrocarbon generation times. Microprobe and optical analyses demonstrate variations in mineralogical composition, particularly in FIV/FV-filled calcite and dolomite cements (12.2 ± 1.5 Ma and 5.5 Ma), highlighting the periods of conduit formation for the hydrocarbon migration. Backscattered electron (BSE) imaging reveals a textural alteration of these cements, especially those associated with fluorite precipitation, which further support the hydrothermal entrapment associated with the hydrocarbon migration. The hydrocarbon entrapment appeared in at least two episodes under subsurface setting under temperatures exceeding 100 °C. In summary, the significant meaningful ages and compositional analyses obtained from this study reveal crucial insights into the dynamics of fracture-filling cements and hydrocarbon entrapment mechanisms within the petroleum source rock formation. The novelty of these data would enhance our understanding of the complex relationship between structural geology and migration conduits, highlighting the influence of fracture-filling cements on hydrocarbon accumulation and reservoir quality as a main target for hydrocarbon field development. Full article

The Western Qinling Orogenic Belt, China’s second-largest Au-metallogenic province, hosts numerous polymetallic deposits, with gold resources particularly concentrated in the northwestern Xiahe–Hezuo area. The Changshitougounao gold deposit, located south of the Xiahe Fault, comprises disseminated ores controlled by near E–W-trending faults and is primarily hosted in quartz diorite and the Lower Triassic Longwuhe Formation. Zircon LA–ICP–MS U–Pb dating of fresh quartz diorite yields an age of 241.8 ± 2.6 Ma. Two generations of monazite were identified: type I magmatic monazite and type II hydrothermal monazite. Type I monazite is intergrown with feldspar, quartz, and biotite, and in situ LA–ICP–MS U–Pb analysis gives an age of 239.2 ± 2.2 Ma. Type II monazite occurs as irregular granular aggregates associated with Au-bearing sulfides and hydrothermal sericite, with an in situ U–Pb age of 230 ± 3.5 Ma. Apatite, also coeval with Au-bearing sulfides and type II monazite, yields an LA–ICP–MS U–Pb age of 230.9 ± 2.5 Ma and 230.7 ± 3.0 Ma. Zircon and type I monazite thus constrain the emplacement of the ore-bearing quartz diorite to ca. 240 Ma, whereas hydrothermal type II monazite and apatite constrain the timing of mineralization to ca. 230 Ma. The ~10 Ma interval between magmatism and mineralization indicates that goldmineralization in the Changshitougounao deposit is decoupled from Early Triassic magmatic activity. Integrating previous studies of the West Qinling geodynamic evolution, we infer that the Changshitougounao deposit formed during collisional orogenesis, in response to the closure of the Paleo-Tethys Ocean. Consequently, the Changshitougounao gold deposit is best classified as an orogenic gold system. Pyrite–arsenopyrite and sericite alteration serve as effective exploration vectors, and the contact zone between quartz diorite veins and slate represents a favorable structural setting for ore prospecting. Full article

Addressing the technological bottlenecks in the efficient utilization of clay-type Li deposits in China, this study systematically investigates Li occurrence states and develops clean extraction processes using the Jinyinshan clay-type Li deposit in southern Hubei as a case study. The research aims to provide technical guidance for subsequent geological exploration and development of such deposits. Analytical techniques, including AMICS, EPMA, and LA-ICP-MS, reveal that Li primarily occurs in structurally bound forms within cookeite (82.55% of total Li), illite (6.65%), and rectorite (5.20%), with mineral particle sizes concentrated in fine-grained fractions (<45 μm). Leveraging process mineralogical insights, two industrially adaptable blank roasting–acid leaching processes were innovatively developed. Process I employs a full flow of blank roasting–hydrochloric acid leaching–Li-Al separation–Ca/Mg removal–concentration for Li precipitation–three-stage counter-current washing. Optimizing roasting temperature (600 °C), hydrochloric acid concentration (18 wt%), and leaching parameters achieved a 92.37% Li leaching rate. Multi-step purification yielded lithium carbonate with >99% Li₂CO₃ purity and an overall Li recovery of 73.89%. Process II follows blank roasting–sulfuric acid leaching–Al removal via alum precipitation–Al/Fe removal–freeze crystallization for sodium sulfate removal–Ca/Mg removal–concentration for Li precipitation–three-stage counter-current washing. Parameter optimization and freezing impurity removal achieved an 89.11% Li leaching rate, producing lithium carbonate with >98.85% Li₂CO₃ content alongside by-products like crude sodium chloride and ammonium alum. Both processes enable resource utilization of Al-rich residues, with the hydrochloric acid-based method excelling in stability and the sulfuric acid-based approach offering superior by-product valorization potential. This low-energy, high-yield clean extraction system provides critical theoretical and technical foundations for scaling clay-type Li deposit utilization, advancing green Li extraction and industrial chain development. Full article

The Matra As–Sb deposit (Alpine Corsica, France) is hosted in the normal N–S trending Matra Fault. Sulfide minerals in ore consist of realgar, stibnite, and pyrite with minor orpiment and hörnesite. The gangue includes quartz, dolomite, and calcite. In this study, the microstructural analysis of selected ore samples has been combined with the geochemical characterization of the sulfides. The results depict a succession of events that record the evolution of the ore deposit related to fault movement. In the pre–ore stage, plumose, crustiform, jigsaw, and feathery textures of quartz testify to a short–lived boiling event. The mineral assemblage of the main–ore stage includes an Fe(–Zn) substage dominated by the formation of different textures of pyrite. In general, pyrite samples contain significant concentrations of As (≤32,231 ppm) and Sb (≤10,684 ppm), with lesser amounts of by Tl (≤1257 ppm) and Ni (≤174 ppm). This is followed by an Sb–As–Fe substage of pyrite–stibnite–realgar ±orpiment. The precipitation of the sulfides was mainly driven by changes in ƒS₂. The increasing level of oxidation is attributed to a progressive influx of meteoric water resulting from reactivation of the Matra Fault. Full article

The most important bauxite deposits in Türkiye are located in the Seydişehir (Konya) and Akseki (Antalya) regions, situated along the western Taurus Mountain, with a total reserve of approximately 44 million tons. Some of the bauxite deposits have been exploited for alumina since the 1970s. In this study, bauxite samples, collected from six different deposits were examined to determine their mineralogical and chemical composition, as well as their REE content, with the aim of identifying which bauxite types are enriched in REEs and assessing their economic potential. The samples included massive, oolitic, and brecciated bauxite types, which were analyzed using optical microscopy, X-ray diffraction (XRD), X-ray fluorescence (XRF) and inductive coupled plasma-mass spectrometry (ICP-MS), field emission scanning electron microscopy (FESEM-EDX), and electron probe micro-analysis (EPMA). Massive bauxites were found to be more homogeneous in both mineralogical and chemical composition, predominantly composed of diaspore, boehmite, and rare gibbsite. Hematite is the most abundant iron oxide mineral in all bauxites, while goethite, rutile, and anatase occur in smaller quantities. Quartz, feldspar, kaolinite, dolomite, and pyrite were specifically determined in brecciated bauxites. Average oxide contents were determined as 52.94% Al₂O₃, 18.21% Fe₂O₃, 7.04% TiO₂, and 2.69% SiO₂. Na₂O, K₂O, and MgO values are typically below 0.5%, while CaO averages 3.54%. The total REE content of the bauxites ranged from 161 to 4072 ppm, with an average of 723 ppm. Oolitic-massive bauxites exhibit the highest REE enrichment. Cerium (Ce) was the most abundant REE, ranging from 87 to 453 ppm (avg. 218 ppm), followed by lanthanum (La), which reached up to 2561 ppm in some of the massive bauxite samples. LREEs such as La, Ce, Pr, and Nd were notably enriched compared to HREEs. The lack of a positive correlation between REEs and major element oxides, as well as with their occurrences in distinct association with Al- and Fe-oxides-hydroxides based on FESEM-EDS and EPMA analyses, suggests that the REEs are present as discrete mineral phases. Furthermore, these findings indicate that the REEs are not incorporated into the crystal structures of other minerals through isomorphic substitution or adsorption. Full article

Quartz from four typical but contrasting peralkaline quartz-saturated granite systems (Khan Bogd and Khalzan Buregte plutons (Mongolia), Ivigtut stock (Greenland), Europa and Madeira plutons (Pitinga magmatic province, Brazil)) was analyzed using LA-ICP-MS to define the range of selected trace element content and trends in their evolution and to compare this content with published data from granitoids of other geochemical types. The evaluation of about 1100 analyses found the studied trace elements mostly in ranges <0.01–18 ppm Li (median 2.41 ppm), 1.2–77 ppm Ti (median 8.2 ppm), 8.3–163 ppm Al (median 42 ppm) and 0.05–5.7 ppm Ge (median 0.98 ppm) (in all cases 5% of the lowest and 5% of the highest values were omitted). Quartz from geochemically less evolved riebeckite-bearing granite plutons shows no Ti/Ge fractionation and displays either a positive Ti–Al correlation or no Ti–Al correlation. More fractionated and potentially mineralized peralkaline magmatic systems were formed within two distinct magmatic episodes: quartz from the older phases is relatively Ti-rich and evolved via Ti decrease with no possible Ge enrichment, while quartz from younger phases is Ti-poor from the beginning and has the ability of enrichment in Al and Ge. Relative enrichment in Al and increase in Ge/Ti value of quartz can serve as a supporting method for the identification of potentially ore-bearing magmatic systems. Full article

The Tuztaşı low-sulfidation epithermal Au–Ag deposit (Biga Peninsula, Türkiye) records a multi-stage hydrothermal history that can be interpreted through the trace and rare-earth-element (REE) chemistry of quartz. High-precision LA-ICP-MS analyses of five representative quartz samples (23 ablation spots; 10 analytically robust) reveal two fluid stages. Early fluids were cold, dilute meteoric waters (δ¹⁸O₍H₂O₎ ≈ −6.8 to +0.7‰), whereas later fluids circulated deeper, interacted with felsic basement rocks, and evolved in composition. Mineralized quartz displays marked enrichment in As (raw mean = 2854 ± 6821 ppm; filtered mean = 70 ± 93 ppm; one spot 16,775 ppm), K (498 ± 179 ppm), and Sb (57.8 ± 113 ppm), coupled with low Ti/Al (<0.005) and elevated Ge/Si (0.14–0.65 µmol mol⁻¹). Chondrite-normalized REE patterns show pronounced but variable LREE enrichment ((La/Yb)_n ≤ 45.3; ΣLREE/ΣHREE up to 10.8) and strongly positive Eu anomalies (δEu ≤ 9.3) with slightly negative Ce anomalies (δCe ≈ 0.29); negligible Ce–Eu covariance (r² ≈ 0.05) indicates discrete redox pulses. These signatures indicate chemically evolved, reducing fluids conducive to Au–Ag deposition. By contrast, barren quartz is characterized by lower pathfinder-element contents, less fractionated REE profiles, higher Ti/Al, and weaker Eu anomalies. A composite exploration toolkit emerges: As > 700 ppm, As/Sb > 25, Ti/Al < 0.005, Ge/Si > 0.15 µmol mol⁻¹, and δEu ≫ 1 reliably identify ore-bearing zones when integrated with δ¹⁸O data and fluid-inclusion microthermometry from earlier studies on the same vein system. This study provides one of the first systematic applications of integrated trace-element and REE analysis of quartz to a Turkish low-sulfidation epithermal system, offering an applicable model for vectoring mineralization in analogous settings worldwide. Full article

Rare earth elements (REEs) are emerging soil contaminants due to increasing fertilizer use, mining activities, and technological applications. However, few studies have assessed their concentrations in soils or associated environmental risks. Here, we evaluate the influence of land cover types (Eucalyptus plantation, forest, and pasture), parent material, and soil physicochemical properties (predictor variables) on REE content in the Brazilian Atlantic Forest and measure pseudo-total REE content using inductively coupled plasma mass spectrometry (ICP-MS). Differences in REE content across land cover types, parent materials, and soil properties were assessed using similarity and variance analyses (ANOSIM, ANOVA, and Kruskal–Wallis) followed by post hoc tests (Tukey HSD and Dunn’s). We used model selection based on the Akaike criterion (ΔAICc < 2) to determine the influence of predictor variables on REE content. Our results showed that parent materials (igneous and metamorphic rocks) were the best predictors, yielding plausible models (Adj R² ≥ 0.3) for Y, δEu, and La_N/Sa_N. In contrast, Ca:Mg alone provided a plausible model (Adj R² = 0.15) for δCe anomalies, while clay content (Adj R² = 0.11) influenced the Sa_N/Yb_N ratio, though soil properties had weaker effects than parent materials. However, we found no evidence that Eucalyptus plantations or pastures under non-intensive management increase REE content in Brazilian Atlantic Forest soils. Full article

Arsenic (As) and cadmium (Cd) in rice grains are major global food safety concerns. Iron (Fe) can help reduce both, but current Fe treatments suffer from poor stability, low leaf absorption, and fast soil immobilization, with unclear underlying mechanisms. To address these issues, an Fe-based metal–organic framework (MIL-88) was modified with sodium alginate (SA) to form MIL-88@SA. Its stability as a foliar inhibitor and its leaf absorption were tested, and its effects on As and Cd accumulation in rice were compared with those of soluble Fe (FeCl₃) and chelating Fe (HA + FeCl₃) in a field study on As–Cd co-contaminated rice paddies. Compared with the control, MIL-88@SA outperformed or matched the other Fe treatments. A single foliar spray during the tillering stage increased the rice yield by 19% and reduced the inorganic As and Cd content in the grains by 22.8% and 67.8%, respectively, while the other Fe treatments required two sprays. Its superior performance was attributed to better leaf affinity and thermal stability. Laser ablation inductively coupled plasma–mass spectrometry (LA–ICP–MS) and confocal laser scanning microscopy (CLSM) analyses revealed that Fe improved photosynthesis and alleviated As–Cd stress in leaves, MIL-88@SA promoted As and Cd redistribution, and Fe–Cd co-accumulation in leaf veins enhanced Cd retention in leaves. Full article

The Yangtze Block, with its widespread Neoproterozoic mafic–felsic magmatic rock series and volcanic–sedimentary rock assemblages, is one of the key windows for reconstructing the assembly and fragmentation process of Rodinia. This study focuses on the Taoyuan syenogranite from the Micangshan Massif on the northern Yangtze Block, by conducting systematic chronology, mineralogy, and geochemistry analyses to investigate their source, petrogenesis, and tectonic setting. LA-ICP-MS U–Pb geochronology reveals that the medium- to coarse-grained and medium- to fine-grained syenogranites have crystallization ages of 878 ± 4.2 Ma and 880 ± 6.5 Ma, respectively. These syenogranites have aluminum saturation index (A/CNK) values ranging from 0.79 to 1.06, indicating quasi-aluminous to weakly peraluminous compositions, and are classified as calc-alkaline I-type granites. The geochemical indicators of these rocks, including Mg^# (44–48, mean 46), Zr/Hf (40.07), Nb/La (0.4), and zircon εHf(t) values (+9.2 to +10.9), collectively indicate a depleted lithospheric mantle source. The mantle source was metasomatized by subduction-derived fluids and sediment melts prior to partial melting as evidenced by their higher Mg^#, elevated Ba content, and distinctive ratios (Rb/Y, Nb/Y, Th/Yb, Th/Sm, Th/Ce, and Ba/La). Integrating regional data, this study confirms crust–mantle interaction along the northern Yangtze during the early Neoproterozoic, supporting a sustained subduction-related tectonic setting. Full article

The Oligocene Dongying Formation beach-bar system, widely distributed in the HHK Depression of the Bohai Bay Basin, constitutes a key target for mid-deep hydrocarbon exploration, though its provenance remains controversial due to complex peripheral source terrains. To address this, we developed an integrated methodology combining LA-ICP-MS zircon U-Pb dating with whole-rock rare earth element (REE) analysis, facilitating provenance studies in areas with limited drilling and heavy mineral data. Analysis of 849 high-concordance zircons (concordance >90%) from 12 samples across 5 wells revealed that Geochemical homogeneity is evidenced by strongly consistent moving-average trendlines of detrital zircon U-Pb ages among the southern/northern provenances and the central uplift zone, complemented by uniform REE patterns characterized by HREE (Gd-Lu) enrichment and LREE depletion; geochemical disparities manifest as dual dominant age peaks (500–1000 Ma and 1800–3100 Ma) in the southern provenance and central uplift samples, contrasting with three distinct peaks (65–135 Ma, 500–1000 Ma, and 1800–3100 Ma) in the northern provenance; spatial quantification via multidimensional scaling (MDS) demonstrates closer affinity between the southern provenance and central uplift (d_ij = 4.472) than to the northern provenance (d_ij = 6.708). Collectively, these results confirm a dual (north–south) provenance system for the central uplift beach-bar deposits, with the southern provenance dominant and the northern acting as a subsidiary source. This work establishes a dual-provenance beach-bar model, providing a universal theoretical and technical framework for provenance analysis in hydrocarbon exploration within analogous settings. Full article

Volcanic eruptions release gases and particulates that may adversely affect human health. The Tajogaite eruption on La Palma provided a unique opportunity to evaluate inorganic pollutant exposure in a directly affected population. As part of the ISVOLCAN study, blood samples from 393 adults residing in the island’s western region were analyzed for 43 inorganic elements using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), including 20 toxic elements identified by the Agency for Toxic Substances and Disease Registry (ATSDR). The median age of participants was 51 years, and 56.7% were female. Higher levels of Hg and Mn were associated with long-term occupational exposure, while smoking was linked to elevated Cd, Pb, and Sr levels. Participants living within 6.5 km of the volcano had significantly higher concentrations of Al and Ti. Ash cleanup activities were associated with increased levels of Ni and Cu, and those spending over five hours outdoors daily showed elevated Se and Pb. This is the first biomonitoring study to assess blood concentrations of inorganic pollutants in a population exposed to volcanic emissions. The findings highlight key exposure factors and underscore the need for continued research to assess long-term health effects and inform public health measures. Full article