Search Results (129)

The magmatic Ni-Co-Cu mineralization in the Iken deposit in the central part of the Kun-Manie complex, Amur Oblast, Russia, hosted by an olivine-bearing websterite, is of a low-sulfide type. The fine-grained disseminations of base metal sulfides (BMS), dominantly pyrrhotite, pentlandite (a major source of Ni of industrial importance), and chalcopyrite, are followed by a scarce Pd-Pt-Ag mineralization. Elevated contents of Al in orthopyroxene (mean 2.78 wt.% Al₂O₃) along with Al–Na enrichment in clinopyroxene (diopside; mean 5.10 wt.% Al₂O₃) are associated with highly aluminous compositions of low-chromium members of the spinel–hercynite series. High levels of TiO₂ in kaersutite and titanian phlogopite also reflect a pronounced degree of fractionation of the ore-forming melt. Minor portions of sulfide melt are distributed evenly as a result of immiscibility at advanced stages of orthopyroxene crystallization, after the formation of olivine. Differentiated grains of droplet-like BMS largely settled in situ close to grain boundaries of orthopyroxene or occupied interstitial spaces of pyroxenes and olivine in association with spinel–hercynite and fluorapatite. A combination of late saturation in S with relatively quick cooling rates of the hypabyssal body prevented the effective settlement and accumulation of sulfide droplets in the ore zone. The well-developed lamellae of troilite (Fe₅₀S₅₀) exsolved from the host pyrrhotite Fe₄₈S₅₂ during subsolidus cooling, as a consequence of a low-temperature reaction triggered by a sudden drop in fO₂. An influx of mantle-derived fluid bearing CO₂, CO, and CH₄ with the rising magma could be the primary cause of the fO₂ reduction. Also, graphite-bearing metasedimentary rocks could have been assimilated. Tiny grains of minerals of noble metals (moncheite and merenskyite with essential amounts of melonite component, sperrylite, hessite, alloy Au_63.2Ag_36.8, and argentopentlandite) deposited late in a fluid-enriched medium under submagmatic conditions. Full article

The lamprophyre dikes and multi-generational pyrite and arsenopyrite developed in the Jinshan gold deposit in the West Qinling metallogenic belt provide critical evidence for understanding the role of mantle-derived magmatism in gold mineralization processes. In this study, we conducted zircon U-Pb dating of lamprophyre to constrain the timing of magmatic activity and the mineralization age, and performed EMPA and LA-ICP-MS analyses on sulfides from the main metallogenic stage (Py II–III, Apy II–III) and lamprophyre-hosted pyrite (Py L) to constrain the formation conditions and metal sources of the Jinshan deposit. The results show that the mantle-derived magmatism represented by lamprophyre yields an age of 206 ± 2 Ma, which provides a lower-limit constraint on the timing of gold mineralization, corresponding to the subduction-to-extension transition period in the region. Stage II mineralization occurred at 270–320 °C with logƒS₂ of −9 to −5, dominantly as Au-HS complexes, indicating medium-temperature hydrothermal conditions with low sulfur fugacity, consistent with microscopic mineral assemblages and thermodynamic simulations. Systematic δ³⁴S variations reveal: stage II values (9.24–5‰) indicate granitic/Devonian sedimentary sources; Py L values (2.19–3.6‰) reflect mantle contributions; stage III signatures (−2.3–1.93‰) record late meteoric water mixing. Complementary δ⁵⁶Fe data show that Py II (0.2–0.3‰) and Py L (0.58–0.68‰) preserve magmatic fingerprints, while negative values of Py III (−2.29 to −0.71‰) document increasing sedimentary Fe incorporation. Combined with geochronology, S-Fe isotopes, and physicochemical constraints, we propose that the Jinshan gold deposit formed in a tectonic setting transitioning from compression to extension during the Late Indosinian (ca. 237–201 Ma). Mineralization was initiated by the partial melting of the metasomatized mantle, where hydrous magmas efficiently extracted Au and volatiles. These components ascended through transcrustal faults, with Au partitioning into exsolved fluids that precipitated gold through immiscibility and boiling in secondary structures. Full article

Chlorine (Cl) and sulfur (S) are two crucial mineralizing agents in silicate melts, and are closely related to the genesis of metallic mineral deposits. Magmatic ore deposits usually form in mafic–ultramafic silicate melts by the separation (liquation) of a cooling, sulfur-rich magma into two immiscible liquids. It is not easy to identify the complexation between gold (Au), cooper (Cu) and Cl, S using the current experiment methods, and the coordination of Au and Cu with Cl and S is still unclear in mafic–ultramafic silicate melts. In this study, by using first-principles molecular dynamics technique, we investigated the structure of Au, Cu, Cl and S in the (a) anhydrous and (b) hydrous peridotite melt to reveal their coordination geochemistry. Our results show that Si⁴⁺–Cl⁻, Cu⁺–O²⁻, Au⁺–O²⁻, Cu⁺–Cl⁻, Au⁺–Cl⁻, Au⁺–S²⁻, and Cu⁺–S²⁻ cannot form stable ion pairs in silicate melts; therefore, Au⁺ and Cu⁺ cannot form stable complexes with S²⁻, O²⁻ or Cl⁻ in the melts. But the diffusion coefficients of Au⁺, Cu⁺, S²⁻ and Cl⁻, their RDF values and the bonding time ratio of the silicate melt systems show that, although they cannot form stable complexes, within the range of effective chemical bond lengths, they have a high probability of approaching and interacting with each other, which enables them to form crystal embryos or liquid-phase molecules during magma evolution. Full article

Granitic rocks dominate Earth’s continental crust, yet the Hadean record is severely limited. Extraterrestrial evolved lithologies, crystallized under predominantly anhydrous, plate tectonics-free conditions analogous to those of early Earth, provide valuable analogues. This review synthesizes lunar, asteroidal, Martian, and candidate Venus/Mercury data, revealing that partial melting of mafic protoliths, not fractional crystallization or silicate liquid immiscibility, represents the dominant formation mechanism. Granitic magmatism persisted episodically from merely 1.11 Myr after Solar System formation through at least 3.87 Ga, with estimated abundances of 0.2%–2% representing a conservative lower limit. These findings imply that Hadean Earth possessed the thermal and compositional prerequisites for analogous magmatism, suggesting that substantial felsic material may have been present, though quantitative estimates remain unwarranted given current data limitations. By establishing a comparative planetary framework, this study illuminates pathways for reconstructing Hadean crustal differential processes, highlighting priorities for future exploration missions targeting cryptic silicic reservoirs, particularly deep-crustal exposures in large lunar impact basins and in situ characterization of Venusian highland terrains. Full article

In this work, compatibilized poly(lactic acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) blends were developed and characterized, to be potentially utilized as biodegradable self-healing matrices for composite laminates. Blends containing 10, 20 and 30%wt of PBAT and 0.5 phr of an epoxy-based compatibilizer were prepared by melt compounding and hot pressing. Rheological measurements showed that moduli and complex viscosity generally increased with PBAT content, while maintaining viscosity levels suitable for conventional melt-processing operations. FT-IR and FESEM analyses confirmed the formation of an immiscible but well-compatibilized morphology, characterized by a homogeneous dispersion of PBAT domains within the PLA phase. Mechanical tests revealed a decrease in tensile modulus (up to 44%), strength (up to 45%) and fracture toughness (up to 40%) with a PBAT content up to 30%wt. Self-healing was evaluated by measuring the fracture toughness (K_IC) recovery after thermal treatment at 140 °C. After healing, the blend containing 20%wt of PBAT exhibited a self-healing efficiency of 64% under impact conditions, which was attributed to the smoother fracture surface generated at an elevated strain rate that facilitated a more effective flow of the molten PBAT phase across the crack interface during healing. The formulation containing 20%wt of PBAT featured the best balance between mechanical performance and self-healing efficiency. Full article

The extraction of high-purity sodium tungstate from complex wolframite concentrates presents significant challenges due to the limitations of conventional processing methods, which are often energy-intensive and generate substantial secondary waste. In this study, we propose a novel phase-regulated alkali fusion approach for the one-step production of high-purity Na₂WO₄. Using phase-diagram calculations with FactSage in the Na-Fe-Mn-Si-O system, SiO₂ was introduced to regulate slag formation, promoting immiscibility between the silicate slag and Na₂WO₄ melt. This resulted in a clear stratification of the phases at 1000 °C, enabling spontaneous separation of the Na₂WO₄-rich salt phase from the slag. The optimized conditions achieved a sodium tungstate purity of 98.76%, with a tungsten recovery rate of 98.91%. Furthermore, impurity elements such as Fe and Mn were preferentially retained in stable silicate/oxide phases within the slag, contributing to the high purity of the sodium tungstate product. This method offers a simplified and environmentally friendly alternative to traditional hydrometallurgical and pyrometallurgical processes, with significant implications for the efficient utilization of complex tungsten resources. Full article

Interstitial microstructures in igneous rocks record key evidence of late-stage evolution processes. In order to constrain the late-stage evolution of a Baima gabbro pegmatite (Panxi region, SW (Southwestern Sichuan Province), China), we investigated its mineral compositions and late-stage microstructures. These microstructures include replacive symplectites and fish-hook clinopyroxene. Replacive symplectites include fine-grained lamellar intergrowths of anorthite (An)-rich plagioclase + clinopyroxene/amphibole/biotite that are rooted to Fe-Ti oxides and replacing nearby plagioclase primocrysts (Type I) and intergrowths of An-rich plagioclase + clinopyroxene/amphibole that are rooted to olivine and replacing nearby plagioclase primocrysts (Type II). Rare replacive symplectites composed of biotite + plagioclase are also present. Those replacive symplectites and fish-hook clinopyroxene grew at a late magmatic stage with temperatures of 867–1023 °C. An-rich plagioclase in the replacive symplectites and fish-hook textures have An contents up to 94 mol.%, much higher than those of plagioclase primocrysts. Interstitial microstructures are interpreted to reflect interaction between primocrysts and an Fe-rich residual interstitial liquid, consistent with separation and migration of conjugate immiscible melts in a crystal mush. We propose that the hydrous interstitial melt in the Baima gabbro pegmatite may have undergone silicate immiscibility during late-stage magma crystallization. As the crystal fraction increased, crystal-mush compaction and porous melt migration likely became the primary controls on the evolution of the late-stage interstitial melt, rather than convection or diffusion. Full article

During the magmatic stage, base and rarer metals segregate from silicate melts to form ore deposits. The usual case is the porphyry (PD) type (Cu, Mo, and W) above subduction zones. The metal grade increases from some ppb or ppm up to percent levels. A new type of trans-porphyry (TPD) deposits (Sn, Ta, Nb, and gems) results from large-scale shear between cratons within continental plates, internal decoupling, and vertical motion. The bulk ore generation process develops along three stages: from magma generation, emplacement, and the formation of an immiscible magmatic phase (MIP), fluids, and melt. However, in TPD, metals segregate from the crust during melting below 800 °C, biotites break down, and the melt remains below the critical point (731 °C). Fluid advection competes with chemical diffusion, yielding the required enrichment. The subcritical MIP splits into a silicate-rich and an aqueous-rich phase, which are both incompatible with each other. Granite, pegmatites, and greisen coexist in the magma chamber. Their respective extraction from a composite mush involves electron exchanges between charges, or orbitals, yielding metal oxides through chemical diffusion. In contrast, in metals (Nb and Ta) observed in pegmatites, and also in gems, electrons rearrange their electronic cloud through their polarizability. Lastly, gems independently grow under the influence of the extremely hard fluids (Li, Be, and B). Magma generation, involving the lower crust (garnet and pyroxene), results in melts that form the two observed pegmatite groups (NYF and LCT), with each being associated with alkaline (A-type) or continental (S-type) granitic melts. Full article

In this study, the properties of poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) blends were analyzed according to the PBS content during the manufacture of the blend. However, the inherent immiscibility between PLA and PBS often leads to phase separation and limited mechanical performance, particularly in melt-spun fiber applications, which restrict their practical use. To increase the miscibility of the PLA/PBS blend, methylene diphenyl diisocyanate (MDI) was added up to 0.8 wt.%, and the characteristics were analyzed via thermogravimetric analysis, differential scanning calorimetry, viscosity measurements, dynamic mechanical analysis, and Fourier-transform infrared spectroscopy. As the PBS content in the blend increased, the thermal stability, viscosity, elastic properties, and glass transition temperature decreased. In contrast, as the MDI content in the PLA/PBS blend increased, the thermal stability, viscosity, elastic properties, and glass transition temperature increased. The results revealed that the miscibility of the PLA/PBS blend increased as the MDI content in the blend increased. Additionally, the tensile strength and elongation of the PLA/PBS blend fibers manufactured through melt spinning were analyzed. While the tensile strength decreased as the PBS content increased, the tensile strength and elongation considerably improved as the MDI content in the blend increased. Specifically, the tensile strength of the PLA/PBS blend fibers increased from 2.55 to 2.99 gf/de, corresponding to an improvement of approximately 17%, while the elongation at break increased from 22.48% to 41.64%, representing an enhancement of approximately 85% with increasing MDI content. Full article

A large, low-grade Fe–Ti–V oxide deposit occurs within the Xiaohaizi Ultramafic–Mafic intrusion. Based on petrographic observations and electron probe microanalysis (EPMA) of amphibole, this study examines the magmatic evolution and ore-forming processes of the intrusion through analyses of amphibole occurrence, mineral chemistry, and crystallization conditions. Five textural types of amphibole were identified: (i) inclusions, (ii) co-crystallization with early silicates, (iii) reaction rims, (iv) co-crystallization with late Fe–Ti oxides, and (v) phenocrysts. The amphiboles are calcic varieties, mainly composed of magnesio-hastingsite, kaersutite, and tschermakite. Crystallization occurred at temperatures of 901–1013 °C and pressures of 254–424 MPa, with ΔNNO values ranging from −1.3 to +2.8 and estimated melt H₂O contents of 3.3–7.1 wt.%, corresponding to crystallization depths of 9.6–16.0 km. Importantly, the crystallization interval of the Fe–Ti oxides is defined by these amphibole-assemblage conditions, as evidenced by their direct intergrowth. Integration of mineralogical and geochemical data indicates that the Xiaohaizi intrusion underwent four distinct stages of magmatic evolution. During these stages, the crystallization of Fe–Ti oxides was accompanied by notable fluctuations in oxygen fugacity and melt water content. These results suggest that fractional crystallization played a dominant role in ore formation, with possible late-stage liquid immiscibility observed at the mineral scale. Overall, this study proposes that the Xiaohaizi Fe–Ti–V oxide deposit represents a magmatic conduit-type ore-forming system developed within a crystal mush. The enrichment of Fe–Ti oxides is strongly associated with hydrous melts and elevated oxygen fugacity conditions. Full article

The environmental impact of petroleum-based plastics has accelerated the search for sustainable alternatives in food packaging. Polylactic acid (PLA), a biobased and compostable polymer, is among the most promising candidates, yet its inherent brittleness and poor moisture barrier limit its application in high-humidity contexts such as dairy packaging. This study investigates immiscible PLA/poly(butylene succinate-co-adipate) (PBSA) blend films as potential biobased packaging materials for perishable foods. Even if these blends have been already studied, limited attention has been given to the systematic characterization of the baseline barrier properties of unmodified PLA/PBSA blends in contact with liquid dairy products. Four blend ratios (PLA/PBSA = 30/70, 40/60, 50/50, 60/40 wt%) were prepared via micro-compounding and compression molding. The films were characterized through melt flow analysis, FTIR, SEM, DSC, DMTA, and tensile testing to evaluate their thermal, morphological, and mechanical properties. Crucially, moisture barrier performance was assessed under simulated dairy conditions by sealing fresh whey at 4 °C and monitoring weight loss over 30 days. Results revealed that while tensile strength and storage modulus (E’) decreased nearly linearly with increasing PBSA content, elongation at break exhibited a non-linear trend, highlighting the complex interplay between blend morphology and mechanical behavior. The study provides a baseline understanding of neat PLA/PBSA blends in contact with liquid dairy, identifying the most promising formulations for future scale-up. These findings contribute to the development of biodegradable packaging systems tailored for refrigerated, high-moisture food applications Full article

The contamination of water by heavy metals is a global problem with distressing health consequences, and researchers have proposed various methods to remove these ions. This study explored poly (lactic acid) (PLA)/ethylene vinyl acetate (EVA)/graphene oxide (GO) composites as possible adsorbents of lead ions from water. GO was synthesized using modified Hummer’s method, and melt mixing was used to prepare the polymer blends and composites. Morphology investigations showed that PLA and EVA were immiscible, GO preferred to settle on the interface between the two polymers, and GO had a partial miscibility and compatibility effect on the polymers, even though cracks and voids were observed with increasing GO content. In water absorption studies, the early hydrolytic degradation of PLA was avoided by incorporating EVA, resulting in reasonable water absorption rates. The 50/50 w/w PLA/EVA blend and its composites showed a high-water intake. In Pb(II) adsorption studies using AAS, all the analyzed samples had very high Pb(II) adsorption capacities, and the 66.5/28.5/5 w/w PLA/EVA/GO composite adsorbed the most lead ions, under basic media, and a 5 h contact time. Adsorption kinetic modeling suggested that a homogenous adsorption process took place, with a precise Langmuir isotherm. The developed materials are promising commercial lead ion adsorbents that are environmentally friendly. Full article

Skarn-type iron ore is economically significant, and numerous skarn ore deposits have been identified in the North China Craton. The newly discovered orbicular diorite in this region is distinguished from other analogous rocks due to the accumulation of large magnetite particles, which may shed new light on the genesis of this ore type. The magnetite in different parts of the orbicular structure exhibits distinct compositional differences. For example, magnetite at the edge has a small particle size (200 μm) and is associated with the minerals plagioclase and hornblende, indicating that it crystallized from normal diorite magma. By contrast, magnetite in the core has a relatively large particle size (>1000 μm), is associated with apatite and actinolite, and contains apatite inclusions as well as numerous pores. The size of magnetite in the mantle falls between that of the edge and the core. The syngenetic minerals of magnetite in the mantle include epidote and plagioclase. The magnetites in the cores of orbicules have a higher content of Ti, Al, Ni, Cr, Sc, Zn, Co, Ga, and Nb than those in the rim. The δ⁵⁶Fe value of the core magnetite (0.46‰–0.78‰) is much higher than that of the mantle and rim magnetite in orbicules. Moreover, the δ⁵⁶Fe value of magnetite increases as the V content of magnetite gradually decreases. This large iron isotope fractionation is likely driven by liquid immiscibility that forms iron-rich melts under high oxygen fugacity. The reaction between magma and carbonate xenoliths (Ca, Mg)CO₃ during magma migration generates abundant CO₂, which significantly increases the oxygen fugacity of the magmatic system. Under the action of CO₂ and other volatile components, liquid immiscibility occurs in the magma chamber, and Fe-rich oxide melts are formed by the melting of carbonate xenoliths. Iron oxides (Fe₃O₄/Fe₂O₃₎ will crystallize close to the liquidus due to high oxygen fugacity. These characteristics of magnetite in the Tanling orbicular diorite (Wuan, China) indicate that diorite magma reacts with carbonate xenoliths to form “Fe-rich melts”, and skarn iron deposits are probably formed by the reaction of intermediate-basic magma with carbonate rocks that generate such “Fe-rich melts”. A possible reaction is as follows: diorite magma + carbonate → (magnetite-actinolite-apatite) + garnet + epidote + feldspar + hornblende + CO₂↑. Full article

This paper presents a detailed analysis of the thermal and flammability properties of polylactide- (PLA) and poly(ethylene terephthalate)- (PET) based polymer blends with biofillers, such as calcium lignosulfonate (CLS), lignosulfonamide (SA) and lignosulfonate modified with tannic acid (BMT) and gallic acid (BMG). Calorimetric studies revealed the presence of two glass transitions, one cold crystallization temperature, and two melting points, confirming the partial immiscibility of the PLA and PET phases. The additives had different effects on the temperatures and ranges of phase transformations—BMT restricted PLA chain mobility, while CLS acted as a nucleating agent that promoted crystallization. Thermogravimetric analyses (TGA) analyses showed that the additives significantly affected the thermal stability under oxidizing conditions, some (e.g., BMG) lowered the onset degradation temperature, while the others (BMT, SA) increased the residual char content. The additives also altered combustion behavior; particularly BMG that most effectively reduced flammability, promoted char formation, and extended combustion time. CLS reduced PET flammability more effectively than PLA, especially at higher PET content (e.g., 65% reduction in PET for 2:1/CLS). SA inhibited only PLA combustion, with strong effects at higher PLA content (up to 76% reduction for 2:1/SA). BMT mainly reduced PET flammability (48% reduction in 1:1/BMT), while BMG inhibited PET more strongly at lower PET content (76% reduction for 2:1/BMG). The effect of each additive also depended on the PLA:PET ratio in the blend. FTIR analysis of the char residues revealed functional groups associated with decomposition products of carboxylic acids and aromatic esters. Ultimately, only blends containing BMT and BMG met the requirements for flammability class FV-1, while SA met FV-2 classification. BMG was the most effective additive, offering enhanced thermal stability, ignition delay, and durable char formation, making it a promising bio- based flame retardant for sustainable polyester materials. Full article

Many granitic enclaves are developed in the volcanic channel of the Xiangshan volcanic basin. To explore their genesis, this study examined the petrography, geochemistry, LA-ICP-MS zircon U–Pb chronology, and zircon Hf isotopes of the granitic enclaves and compared them with the porphyroclastic lavas. In general, the granitic enclaves and porphyroclastic lavas have similar structures, and the rock-forming minerals and accessory minerals have relatively close compositions. In terms of rock geochemical characteristics, the granitic enclaves are richer in silicon and alkalis but have lower abundances of aluminum, magnesium, iron, and calcium than the porphyroclastic lavas. Rb, Th, K, Sm, and other elements are more enriched, whereas Ba, Ti, Nb, P, and other elements are more depleted. The granitic enclaves have lower rare earth contents (195.53 × 10⁻⁶–271.06 × 10⁻⁶) than the porphyroclastic lavas (246.67 × 10⁻⁶–314.27 × 10⁻⁶). The rare earth element distribution curves of the two are generally consistent, both right-leaning, and enriched with light rare earth patterns. The weighted average zircon U–Pb ages of two granitic enclave samples were 135.45 ± 0.54 Ma (MSWD = 0.62, n = 17) and 135.81 ± 0.60 Ma (MSWD = 0.40, n = 20), respectively, which are consistent with the weighted average age of a single porphyroclastic lava sample of 134.01 ± 0.53 Ma (MSWD = 2.0, n = 20). The zircons of the two kinds of rocks crystallize at almost the same temperature. The consistent trend of the rare earth element distribution curve of zircons in the granitic enclaves and the porphyroclastic lava samples indicates that the zircons of the two samples were formed in the same stage. The formation process of granitic enclaves may be that the lower crustal melt is induced to rise, and the crystallization differentiation occurs in the magma reservoir and is stored in the form of crystal mush, forming a shallow crystal mush reservoir. The crystal mush reservoir is composed of a large number of rock-forming minerals such as quartz, feldspar, and biotite, as well as accessory mineral crystals such as zircon and flowable intergranular melt. In the later stage of magma high evolution, a small and short-time magmatic activity caused a large amount of crystalline granitic crystal mush to pour into the volcanic pipeline. In the closed system of volcanic pipeline, the pressure and temperature decreased rapidly, and the supercooling degree increased, and the immiscibility finally formed pale granitic enclaves. Full article