Search Results (116)

Mineral exploration in the Iberian Pyrite Belt follows increasingly deeper targets. The present study introduces an innovative methodology for the detection and identification of blind metallic mineral deposits, in particular volcanogenic massive sulfides based on surface rock coatings. This approach follows the identification pathways of upward metal escape routes and metal distribution in rock fractures located in different anisotropic or isotropic planes above the Neves-Corvo VMS deposit ore lenses, using VP-SEM-EDS and XRD. Coatings are dominated by poorly crystalline to amorphous phases, with goethite and birnessite as the main Fe- and Mn-bearing minerals. Copper, zinc and lead are systematically enriched in coatings developed above or near the ore bodies, reflecting chalcopyrite, sphalerite and galena acidic leaching. Tin shows a restricted and heterogeneous distribution, while Ni and Co display no systematic relationship with the ore bodies. Barium and late Ba–Pb–(Zn) mineralization along fault zones record VMS mineralization. Lead isotopic coating signatures overlap those of IPB massive sulfide deposits, confirming a dominant VMS-derived contribution. Fe–Mn coatings were formed by precipitation from ascending meteoric fluids that leached metals from massive sulfides, their alteration halos, and surrounding lithologies, preserving the geochemical footprint of buried mineralization. This approach constitutes a new patented exploration tool. Full article

The giant Dulong Sn-Zn polymetallic deposit, located in the eastern part of the southeastern Yunnan metallogenic belt, is a world-class ore system. Despite extensive research on the source of tin and its mineralization processes, the specific ore-related intrusion and the source of copper remain highly debated. Recent deep exploration has revealed a deep-seated granite porphyry, yet its geochronological and geochemical characteristics, along with its genetic link to mineralization, are poorly constrained. This study presents new zircon U-Pb age, whole-rock geochemistry, and Sr-Nd-Hf isotopic compositions of this granite porphyry, integrated with a regional comparison to multi-phase Laojunshan granites. LA-ICP-MS zircon U-Pb dating yields a Late Cretaceous age of 85.1 ± 1.2 Ma. The Dulong granite porphyry is strongly peraluminous and high-K calc-alkaline to shoshonitic, exhibiting typical S-type granite affinities with enrichment in Rb, U, and Ta, as well as depletions in Ba, Sr, Nb, and Eu. Isotopic signatures (ε_Nd(t) = −12.5 to −12.0, t_DM2(Nd) = 1.87 to 1.91 Ga; zircon ε_Hf(t) = −10.24 to −1.44, t_DM2(Hf) = 1.24 to 1.79 Ga) suggest that the parental magma was derived from the partial melting of ancient crust, with possible minor input of mantle-derived components in an extensional tectonic setting. The Dulong granite porphyry represents a moderate-to-high temperature, reduced, and highly evolved magmatic system. Notably, its high concentrations of Sn, W, Zn, and Cu indicate that the parental melt was metal-rich, possessing potential for Sn and Cu mineralization. Accordingly, future exploration should prioritize areas characterized by well-developed granite porphyry dykes, skarn–wallrock contact zones, and deep-seated structural intersections. Full article

Baixintan is a magmatic Ni–Cu sulfide deposit discovered in the central Tuwu–Yandong porphyry Cu belt of the Eastern Tianshan Orogen (ETO) of NW China in 2016. It is in close proximity (~5 km) to the Tuwu Cu deposit, the largest Carboniferous porphyry Cu deposit (~336 Ma) in Xinjiang. The Baixintan Ni–Cu ore is characterized by a high Cu/Ni ratio, but the reason for it remains unclear. To resolve this question, we present petrographic, geochronological, whole-rock geochemical, and S, Pb, Cu, and Lu–Hf isotopic data. Ore-related hornblende olivine websterite (HOW) and hornblende olivine gabbro (HOG) were emplaced at 296.6 ± 1.1 Ma and 289.7 ± 1.2 Ma, respectively, which were formed in an Early Permian post-collisional extensional setting. Whole-rock Pb and zircon Lu–Hf isotopes suggest that the parental magmas were predominantly mantle-derived. The Baixintan HOW and HOG contain abundant hornblende and are enriched in LILEs and LREEs but depleted in HFSEs, suggesting subduction-related metasomatism in their magma source. The sulfide (chalcopyrite, pyrrhotite, and pentlandite) δ³⁴S values cluster around 0‰ (–0.13 to 0.11, n = 11), and the chalcopyrite has uniformly negative but variable δ⁶⁵Cu values (–0.96 to –0.13, n = 6), which suggest that the ore-forming materials were mainly derived from the subduction-metasomatized mantle. Olivine Ni contents are significantly lower than those crystallized under sulfide-unsaturated conditions, implying that olivine fractional crystallization was an important trigger for sulfide melt segregation at Baixintan. Baixintan is the only known magmatic Ni–Cu sulfide deposit in the ETO that shares a Cu-preconcentrated, metasomatized mantle source with a giant porphyry Cu system. Copper pre-enrichment in the magma source may be the main factor for the relatively high Cu/Ni ratio observed in the Baixintan deposit. Full article

The Duolong porphyry copper–gold district, located in the northwestern segment of the Bangongco–Nujiang metallogenic belt on the southern margin of the South Qiangtang terrane (Tibet), hosts typical porphyry-style Cu-Au mineralization with well-defined alteration zoning from potassic through chlorite–sericite to propylitic assemblages. Based on integrated in situ major/trace element and sulfur isotope analyses of pyrite and chalcopyrite from different alteration zones, we identify two discrete episodes of magmatic-hydrothermal activity that exerted distinct controls on metal endowment. Sulfur isotope signatures define a systematic evolution from the earliest, high-temperature potassic stage (δ³⁴S: Py-I −3.70 to −1.16‰, mean −2.14‰; Cp-I −4.92 to −0.90‰, mean −2.54‰) through propylitic alteration (Py-II: 1.20‰–5.16‰, mean 3.06‰) to the later chlorite–sericite stage (Py-III: −2.00 to 1.86‰, mean 0.06‰; Cp-II: −2.50 to 0.58‰, mean −0.77‰), tracking progressive fluid cooling and changing fluid sources. Trace element systematics further discriminate these episodes: sulfides from potassic and chlorite–sericite zones are enriched in trace elements, whereas propylitic pyrite is depleted, with potassic pyrite recording the highest Cu concentrations (559–7256 ppm, mean 2302 ppm) and chlorite–sericite pyrite containing the lowest Au contents (0.01–0.59 ppm, mean 0.10 ppm). Gold mineralization occurs as native gold exsolved from chalcopyrite, and the markedly low Au concentrations in chlorite–sericite pyrite (0.01–0.59 ppm, mean 0.10 ppm) demonstrate that gold exsolution was largely completed during the first, high-temperature magmatic-hydrothermal stage. Collectively, these results establish a detailed geochemical framework linking sulfide composition to specific hydrothermal stages, providing new constraints on the processes of porphyry copper–gold mineralization in a collisional setting. Full article

Sandstone-hosted uranium deposits in the western Qaidam Basin are spatially associated with hydrocarbon-bearing structures, yet the specific roles of different sulfur sources in uranium mineralization remain poorly constrained. This study aims to distinguish the contributions of bacterial sulfate reduction and hydrocarbon-associated sulfate reduction to uranium precipitation by integrating detailed petrography, in situ trace element analyses, and sulfur isotope measurements of chalcopyrite from the Yuejin II deposit. Chalcopyrite is restricted to high-grade uranium ores and occurs intergrown with uranium minerals, pyrite, baryte, and carbonate cements. Trace element patterns indicate that oxidizing brines acted as the main transport medium for both uranium and copper, as evidenced by positive correlations between U and brine-related elements (Ba, Sr, Na, K). Positive U-Th correlations with relatively constant Th/U ratios (0.027–0.225) reflect a combination of source composition, fluid transport capacity, and limited thorium remobilization in this near-source, hydrocarbon-rich environment. Correlations between U and high field strength elements (Sn, W) point to a highly evolved granitic origin, with Altyn granitoids likely supplying the copper. Sulfur isotopes show a clear bimodal distribution: one group exhibits heavy δ³⁴S values (+6.9‰ to +18.5‰), while the other shows extremely light values (–36.0‰ to –44.6‰). The light group reflects bacterial sulfate reduction in shallow strata, supported by framboidal pyrite textures, whereas the heavy group corresponds to surface-derived sulfate reduced at hydrocarbon-associated redox fronts, rather than direct incorporation of deep H₂S. The lack of intermediate δ³⁴S values indicates that two discrete sulfur reduction mechanisms coexisted within the same deposit, refining genetic models for uranium mineralization in petroliferous basins and challenging frameworks that invoke a single dominant sulfur source. Full article

The Sepid-Sarve copper deposit is part of an Eocene volcano-sedimentary sequence located in the southern Sabzevar Zone. The copper mineralization occurs at the contact between pyroclastic and lava units with various limestone layers (including marly, Nummulitic, sandy, and clastic limestones). The ore minerals consist of malachite, azurite, chalcocite, digenite, cuprite, tenorite, covellite, and occasionally native copper. The associated hydrothermal fluids show moderate to high salinities, ranging from 3.08 to 13.38 wt.% NaCl equivalent, with homogenization temperatures between 90 and 356 °C, indicating fluid mixing during ore formation. Chalcocite is rarely accompanied by quartz, suggesting low silica content in the ore-forming fluids. The δ³⁴S values of sulfide samples from the Sepid-Sarve deposit range from −23.9 ± 0.3‰ to −2.9 ± 0.2‰, while δ³⁴S values of hydrothermal H₂S range from −24.1 ± 0.3‰ to −21.0 ± 0.3‰. The δ¹⁸O values of hydrothermal fluids associated with mineralization fall within the range of basaltic rocks, meteoric waters, and sedimentary rocks. Geochemical variations in major and trace elements suggest the involvement of continental crustal contamination in the magmatic evolution. The studied volcanic rocks fall within the calc-alkaline to shoshonitic fields, formed in a continental arc setting, and are derived from an enriched mantle source influenced by subduction-related fluids. These rocks are characterized by HREE depletion, moderate LREE enrichment, and a weak negative Eu anomaly. Based on the results, the Sepid-Sarve deposit is classified as a stratabound (Manto-type) copper sulfide deposit, formed in a volcano-sedimentary setting associated with a subduction-related magmatic arc environment. Full article

Magma oxidation state and water content are pivotal factors governing porphyry copper mineralization. The Xiongcun deposit, the only super-large porphyry copper deposit (PCD) formed in an oceanic subduction environment in the Gangdese belt, has been the primary focus of prior research, with limited systematic comparisons conducted among Xiongcun, weakly mineralized, and barren igneous rocks across the Jurassic Arc. Furthermore, the interaction between ore-controlling factors and deep-seated magmatic processes remains poorly understood. This study examines Xiongcun volcanic rocks, as well as weakly mineralized and barren volcanic rocks from the Jurassic Arc, with Dazi and Jiamagou samples from the eastern segment of Jurassia Arc (ESJA) and Xiongcun, Chucun, and Qinze samples from the western segment of Jurassia Arc (WSJA). All samples (168.0–184.8 Ma) are predominantly calc-alkaline, which is typical of arc magmas. Zircon Hf isotopic data reveal pronounced E-W variations but minimal N-S differences, dividing the arc into the WSJA and ESJA subzones. The WSJA volcanic rocks exhibit uniform Hf isotopic signatures (ε_Hf(t) = 11.2–16.3) and young crustal model ages (186–500 Ma), whereas the ESJA mantle source region is heterogeneous, reflecting greater retention of ancient crustal material. Compared to the ESJA, new data from WSJA samples display higher zircon Ce⁴⁺/Ce³⁺ ratios (454 vs. 145), lower T(Zr-Ti) values (716 °C vs. 779 °C), and elevated whole-rock Ba/La ratios. These differences suggest that mineralization contrasts between the two segments arise from varying fluid metasomatism in their source regions, leading to divergent magma oxygen fugacity and water content—critical controls on porphyry Cu formation. The WSJA magmas exhibit higher values in both parameters, while the ESJA lacks significant mineralization potential. Full article

The Apuseni-Banat-Timok-Srednogorie Metallogenic Belt is one of the most important polymetallic metallogenic belts in the western segment of the Tethys, where numerous porphyry-type, skarn-type, and epithermal deposits are developed. However, scholars have noted a lack of systematic chronological and geochemical studies of andesites within this belt. Furthermore, the metallodynamic mechanisms controlling mineralization—such as oceanic plate exhumation and plate tearing—remain controversial. To complement the available research, this study focuses on andesites from the Čukaru Peki area in Serbia and integrates zircon U-Pb dating, molybdenite Re-Os isotopic analysis, and whole-rock geochemical analysis. The results reveal that plagioclase andesitic breccia and fine-grained plagioclase amphibole andesite were emplaced during the Late Cretaceous. Consistently, the molybdenite isochron age (81.46 ± 0.60 Ma, MSWD = 1.30) constrains the mineralization event to the same period. Both rock types exhibit geochemical signatures typical of island arc volcanic rocks, characterized by high SiO₂ contents and low Al₂O₃, MgO, and TiO₂ contents, as well as pronounced fractionation between light and heavy rare earth elements (LREEs and HREEs). The magma source is the mantle wedge metasomatized by fluid-rich melts derived from the dehydration of the subducted oceanic crust. Additionally, the primary magma produced by partial melting of this metasomatized mantle wedge assimilated and was contaminated by continental crustal material predating the Vardar Ocean’s closure during its ascent. Our findings suggest that the regional andesites are products of the exhumation of the Vardar Ocean. This study aims to provide a theoretical foundation for mineral exploration in the Timok ore cluster and, simultaneously, support the identification of ore prospecting targets in andesite alteration zones. Full article

The primary source of drinking water for the people of Tonosí, Panama, is groundwater. This research evaluates the presence of heavy metals and possible hazards by combining geochemical and isotopic analyses. Total Reflection X-ray Fluorescence (TXRF) was used to measure metal levels in water and soil near wells and springs, while stable isotope ratios (δ²H and δ¹⁸O) identified the source of groundwater recharge. Isotopic signatures closely aligned with the Local Meteoric Water Line (LMWL), suggesting meteoric origin and limited evaporation. An analysis of Enrichment Factor (EF) for soil samples, utilizing background values from Coiba and Montijo, showed moderate to substantial enrichment of arsenic, chromium, and copper. Soil enrichment suggests possible dangers with environmental shifts like changes in land use or heavy rainfall. These findings highlight the necessity for continual groundwater observation in rural areas and show the benefits of integrating isotopic and geochemical methods to detect sources of contamination and guide protection strategies. This research improves comprehension of heavy metal exposure in tropical aquifers and offers evidence to aid environmental and public health policymaking. Full article

The Permian Kupferschiefer shale, a key stratigraphic unit within the Zechstein sequence of the Fore-Sudetic Monocline, represents both a metal-rich lithofacies and a potential source rock for hydrocarbon generation. This study presents a comprehensive geochemical characterization of selected Kupferschiefer samples obtained from the Legnica–Głogów Copper District (LGOM) and exploratory boreholes. Analytical methods included Rock-Eval pyrolysis, Py-GC/FID, elemental analysis, TG-FTIR, biomarker profiling, and stable carbon isotope measurements. Results indicate that the shales contain significant amounts of Type II and mixed Type II/III kerogen, derived primarily from marine organic matter with minor terrestrial input. The organic matter maturity, expressed by T_max, places most samples within the oil window. Rock-Eval S2 values exceed 60 mg HC/g rock in some samples, confirming excellent generative potential. Py-GC/FID data further support high hydrocarbon yields, particularly in samples from the CG-4 borehole and LGOM mines. The thermal decomposition of kerogen reveals multiple degradation phases, with evolved gas analysis identifying sulfur-containing compounds and hydrocarbons indicative of sapropelic origin. Isotopic compositions of bitumen and kerogen suggest syngenetic relationships and marine depositional settings, with samples from a North Poland borehole showing isotopic enrichment consistent with post-depositional oxidation. Kinetic parameters calculated using the Kissinger–Akahira–Sunose method demonstrate variable activation energies (107–341 kJ/mol), correlating with differences in organic matter composition and mineral matrix. The observed variability in geochemical properties highlights both regional and facies-dependent influences on the shale’s generative capacity. The study concludes that the Kupferschiefer in southwestern and northern Poland exhibits substantial hydrocarbon generation potential. This potential has been previously underestimated due to the unit’s thinness, but localized zones with high TOC, favorable kerogen type, and low activation energy could be viable exploration targets for natural gas. Full article

Crustaceans are particularly sensitive to copper toxicity, and although the downstream effects of increased copper exposure on the metabolome are often postulated and observed, they are rarely measured. To perform absolute quantification of hydrophilic small-molecule metabolites in the hemolymph of the crustacean Cancer borealis, we derivatized targeted metabolites related to copper toxicity using in-house-developed isotopic N,N-dimethyl leucine (iDiLeu) tags. Selected analytes were pooled at previously determined concentrations to serve as internal standards, and a calibration curve was generated. The sample loss was minimized by optimizing the derivatization-assisted sample cleanup using dispersive liquid–liquid microextraction (DLLME) and hydrophilic–lipophilic balancing (HLB). Calibration curves were then used for the absolute quantification of metabolites of interest following 30 min, 1 h, and 2 h exposures to 10 µM CuCl₂. We found that glutamic acid was downregulated after 2 h of copper exposure, which may disrupt cellular metabolism and increase oxidative stress in crustaceans. These changes could have significant impacts on crustacean populations and the ecosystems they support. Full article

The Chagai porphyry copper belt is a major component of the Tethyan metallogenic domain, which spans approximately 300 km and hosts several giant porphyry copper deposits. The tectonic setting, whether subduction-related or post-collisional, and the deep dynamic processes governing the formation of these giant deposits remain poorly understood. Mafic microgranular enclaves (MMEs), mafic dikes, and multiple porphyries have been documented in the Saindak mining area. This work examines both the ore-rich and non-ore intrusions in the Saindak porphyry Cu-Au deposit, using methods like molybdenite Re-Os dating, U-Pb zircon ages, Hf isotopes, and bulk-rock geochemical data. Geochronological results indicate that ore-fertile and barren porphyries yield ages of 22.15 ± 0.22 Ma and 22.21 ± 0.33 Ma, respectively. Both MMEs and mafic dikes have zircons with nearly identical ²⁰⁶Pb/²³⁸U weighted mean ages (21.21 ± 0.18 Ma and 21.21 ± 0.16 Ma, respectively), corresponding to the age of the host rock. Geochemical and Sr–Nd–Hf isotopic evidence indicates that the Saindak adakites were generated by the subduction of the Arabian oceanic lithosphere under the Eurasian plate, rather than through continental collision. The adakites were mainly formed by the partial melting of a metasomatized mantle wedge, induced by fluids from the dehydrating subducting slab, with minor input from subducted sediments and later crust–mantle interactions during magma ascent. We conclude that shallow subduction of the Arabian plate during the Oligocene–Miocene may have increased the flow of subducted fluids into the sub-arc mantle source of the Chagai arc. This process may have facilitated the widespread deposition of porphyry copper and copper–gold mineralization in the region. Full article

The Aït Abdellah copper deposit in the Bou Azzer-El Graara inlier of the Moroccan Anti-Atlas provides key insights into structurally and lithologically controlled mineralization in Precambrian terranes. The deposit is hosted in feldspathic sandstones of the Tiddiline Group, which unconformably overlie the Bou Azzer ophiolite, and is spatially associated with a NE–SW-trending shear zone. This zone is characterized by mylonitic fabrics, calcite veining, and an extensive network of fractures, reflecting a two-stage deformation history involving early ductile shearing followed by brittle faulting and brecciation. These structural features enhanced rock permeability, enabling fluid flow and metal precipitation. Copper mineralization includes primary sulfides such as chalcopyrite, bornite, pyrite, chalcocite, digenite, and covellite, as well as supergene minerals like malachite, azurite, and chrysocolla. Sulfur isotope values (δ³⁴S = +5.9% to +22.8%) indicate a mixed sulfur source, likely derived from both ophiolitic rocks and volcano-sedimentary sequences. Carbon and oxygen isotope data suggest fluid interaction with marine carbonates and meteoric waters, potentially linked to post-Snowball Earth deglaciation processes. Fluid inclusion studies reveal homogenization temperatures ranging from 195 °C to 310 °C and salinities between 5.7 and 23.2 wt.% NaCl equivalent, supporting a model of fluid mixing between magmatic-hydrothermal and volcano-sedimentary sources. The paragenetic evolution of the deposit comprises three stages: (1) early hydrothermal precipitation of quartz, dolomite, sericite, pyrite, and early chalcopyrite and bornite; (2) a main mineralizing stage characterized by fracturing and deposition of bornite, chalcopyrite, and Ag-bearing sulfosalts; and (3) a late supergene phase with oxidation and secondary enrichment. The Aït Abdellah deposit is best classified as a shear zone-hosted copper system with a complex, multistage mineralization history. The integrated analysis of structural features, mineral assemblages, isotopic signatures, and fluid inclusion data reveals a dynamic interplay between deformation processes, hydrothermal alteration, and evolving fluid sources. Full article

Vineyard soils are frequently contaminated with copper due to the use of Cu fungicides to prevent downy mildew. This study investigated the effects of an aerated compost tea (ACT) made from grape pomace and animal manure on the downward transfer of Cu and on the accumulation of Cu in plants in a sandy loam vineyard soil. Crimson clover and pot marigold were grown in a 40 cm soil column with Cu supplied to the surface at loadings representative of those applied in European vineyards, plus additions of ACT. A source of Cu enriched in the stable isotope ⁶⁵Cu was used to distinguish freshly added Cu (fresh Cu) from Cu already present in the soil (aged Cu). ACT increased the concentration of soluble humic substances (SHS) in pore water in the top 7.5 cm of the column, and increased the concentration of Cu, Al, and Fe in pore water in proportion to the concentration of SHS. The transfer of fresh Cu to deeper soil was limited to the top 5 cm, even after the addition of ACT, although fresh Cu reacted slightly more to ACT than aged Cu. ACT had no effect on Cu phytoextraction but increased the concentration of Cu in roots by almost twofold. Relatively more fresh Cu was transferred to plants than aged Cu, primarily due to its preferential accumulation on the surface. The risk associated with the use of ACT on vineyard soils is not that of promoting the downward transfer of Cu, but rather of increasing Cu availability to plants and likely to other living organisms in the topsoil. Full article

This investigation focuses on anthropogenic impacts on metallic element distribution within coal mining ecosystems, particularly addressing soil contamination risks in the Linhuan region. Researchers conducted comprehensive sampling and analysis of surface soil contaminants, specifically quantifying mercury, copper, zinc, iron, aluminum, and lead concentrations. Through integrated application of receptor modeling (PMF) and mercury isotopic fingerprinting methodology, this study established a quantitative assessment framework for pollution source apportionment. The multi-technique approach enables precise identification of contamination pathways and proportional contributions from different anthropogenic activities in the mining environment. Coupled with a human health risk assessment model, the health risks associated with specific sources were evaluated. The results indicate that the concentrations of Hg, Cu, Zn, Fe, Al, and Pb in the soil of the study area are 9.49, 2.80, 4.01, 11.79, 6.32, and 1.03 times the soil background values, respectively, suggesting a certain degree of enrichment of these six heavy metals in the soil. The PMF source contribution results show that the soil heavy metals in the study area have three sources: natural soil formation, a mixture of coal combustion and traffic activities, and coal mining activities, with contribution rates of 31.23%, 31.59%, and 37.18%, respectively. The health risk assessment results for specific sources indicate that the non-carcinogenic risks of soil heavy metals in the local area require sufficient attention. Hg is the main cause of non-carcinogenic health risks for both groups, making it a priority element for controlling soil heavy metal health risks. Coal mining activities are the main source (52.4%) of non-carcinogenic risks, making them a priority control source for soil heavy metal health risks in the study area. These findings provide a theoretical basis for enhancing the refined management of heavy metal pollution and the prevention of health risks in soils of coal mining areas. Full article