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Ethylene in principle can be obtained via oxidative coupling of methane (OCM), but it is urgently calling for a low-temperature active and selective catalyst. To accomplish this goal, the CexZr1-xO2 solid solutions with varied Ce/Zr molar ratio were modified with Mn2O3-Na2WO4 to fabricate OCM catalysts. The effects of Ce/Zr ratio and Mn2O3-Na2WO4 doping were investigated on the catalyst reactivity for the OCM, showing that the reaction light-off temperature, activity and selectivity are subject to the Ce/Zr molar ratio and Mn2O3-Na2WO4 doping. The promising catalyst with Ce/Zr molar ratio of 0.15/0.85 achieves 25% CH4 conversion with 67% selectivity to C2-C3 at 660 °C and is stable for at least 100 h. The catalysts were systematically studied by CH4-TPSR, O2-TPO/-TPD, CH4-pulse, in-situ FT-IR, EPR and XPS, showing that the Mn2O3-Na2WO4 doped Ce0.15Zr0.85O2 can generate more O2– species thereby leading to a markedly improved activity and selectivity at much lowered reaction temperature.

To better constrain Ca isotopic fractionation during volcanic magma differentiation, we report Ca isotope data for a series of volcanic glasses from the eastern Manus Basin that represent a continuum of compositions comprising basaltic andesite, andesite, dacite, and rhyolite. Our results show that these volcanic glasses exhibit ~0.25‰ variation in Ca isotopic compositions, with δ44/40Ca ranging from 0.81 ± 0.04 to 1.05 ± 0.04‰. The similar trace element patterns and Sr-Nd isotopic compositions exclude source heterogeneity as the cause of the varied Ca isotopic compositions. Due to their low K/Ca ratios and young age, the Ca isotopic variations cannot be attributed to 40K decay. Instead, the observed Ca isotopic variations are primarily controlled by their lithology. Specifically, δ44/40Ca of basaltic andesite (0.81 ± 0.04) and andesite (0.82 ± 0.01) are similar to the averages of reported mid-ocean ridge basalts (MORBs; 0.84 ± 0.10; 2SD, N = 26) and back-arc basin basalts (BABBs; 0.80 ± 0.08; 2SD, N = 21) in literature, but do not correlate with SiO2 or MgO contents, indicating the Ca isotopic fractionation is insignificant during intermediate-mafic magma evolution. As magma differentiation continues, δ44/40Ca of dacite and rhyolite evolves from 0.85 ± 0.01 to 1.05 ± 0.04‰. Moreover, δ44/40Ca of felsic glasses are negatively correlated with Eu/Eu*, which suggests that the increasing δ44/40Ca of felsic glasses is most likely related to plagioclase (Pl) fractional crystallization. Therefore, we conclude that Ca isotopes can behave differently at different stages of volcanic magma differentiation. Modeling of fractional crystallization using rhyolite-MELTS shows that the relative Ca fractions in crystallized minerals (e.g., Pl vs. Cpx) and the Ca isotopic fractionation factor between the residual melt and crystallized Pl (αmelt-Pl, which is likely related to the An number of Pl, magma temperature and kinetic effects during crystallization), provide a plausible explanation for the behavior of Ca isotopes during volcanic magma differentiation.

The latest multichannel seismic data from the Yap subduction zone is presented to investigate the Caroline Ridge fault system, developed by faulting and bending processes within the incoming oceanic plateau. We reveal that horst and graben structures exist along the entire incoming Caroline Ridge adjacent to the trench and that pervasive bending-related faults trending ~N30°E have developed subparallel to the trench. However, the widths of the horst and graben structures decrease gradually from north to south. The two-stage ancient abyssal hill fabrics overlap the incoming Caroline Ridge. Abyssal hill faults trending ~N65°W present large trench-ridge angles (85–90°); in the southern segment, abyssal hill faults trending ~N70°E have relatively low trench-ridge angles (~35–40°). From the Caroline Ridge to the horst and graben structures, the topography decreases, and slump bodies with deformed internal reflections have developed above an irregular reflector. Little stable pelagic sediment with horizontal reflectors accumulates on the horst and graben structures, suggesting that the faulting and bending processes involve long and intense tectonic processes that affect the sedimentary environment. The sedimentary strata and fault distributions differ between the North and South Caroline Ridge, which is primarily attributable to the different rifting processes. Furthermore, we propose that N65°W-trending ancient faults sufficiently decrease the yield strength of the incoming Caroline Ridge to facilitate the bending-related faulting. During subduction, the incoming North Caroline Ridge that has a large degree of rifting and the Sorol Trough, which has a thin crust, may resist less flexural bending and generate the wide horst and graben structures. The ancient faults and rifting model of incoming oceanic plateaus play a significant role in bending-related faulting

Hydrous minerals in the hybridized zone at the slab-mantle interface play a critical role in retaining and transporting fluid mobile elements in subduction zones. The observed high B and As concentrations and high δ11B values in arc magmas were previously thought to have been resulted from the mechanical transport of forearc serpentinites down to subarc depths by mantle corner flows or through subduction channels because B, As, and Sb are mostly released during early stages of subduction. This study provides new insights into the recycling of B, As, and Sb in subduction zones via an in-situ study on a set of carbonate-bearing serpentinite samples from the Mianlue melange complex in the Qinling Orogen. Petrological observations and bulk-rock Sr-Pb isotopes reveal that the Jianchaling serpentinites were formed by interactions between forearc peridotites and sediment-derived fluids at a shallow depth in the subduction channel. Some Jianchaling serpentinites experienced the lizardite to antigorite transition at 300–400 °C with infiltrations of CO2-rich fluids. In contrast, the Liangyazi antigorite serpentinites were produced at a greater depth. Antigorite grains in the Jianchaling serpentinites have lower Feapfu than those in the Liangyazi serpentinites and most antigorite with geochemical data in the literature. Meanwhile, B, As, and Sb concentrations of Fe-poor antigorite from the Jianchaling serpentines (385–653 ppm B, 198–334 ppm As, and 6.24–8.01 ppm Sb) are not only higher than those of the Fe-rich antigorite from the Liangyazi serpentinites but also 2–3.5 times higher than those of the surrounding lizardite. The lower modal percentage of spinel and ferritchromite in antigorite veinlets, together with the lower bulk-rock FeO content of antigorite-lizardite serpentinites than that of lizardite serpentinites from the Jianchaling region, indicates that some FeO might be lost during the lizardite to antigorite transition. The presence of carbonate minerals in the antigorite veinlets and the remarkably high B, As, and Sb concentrations in the Jianchaling antigorite indicate that the penetrating fluids during the lizardite to antigorite transition are most likely derived from sediment and metabasite decarbonations at

The Dongguashan deposit is the largest and deepest Cu (Au) deposit in the Tongling region, eastern China. The presence of skarn and stratiform ore bodies in the same system of the Dongguashan deposit has caused much debate as to whether the mineralization was associated with magmatic-hydrothermal or sedimentary origin. In this study, in situ (LA-ICP-MS and EPMA) elemental compositions of medium-to coarse-grained euhedral pyrite from the stratiform and skarn ore bodies, and pyritization marble are investigated in the Dongguashan deposit. The results of the studied pyrite samples have relatively consistent trace element composition characteristics and several genetically significant elemental combinations. Gold and Ag are mainly of lattice bound appearance in pyrite. The Pb, Cu, Sb and Tl elements are mainly incorporated into the pyrite structure as substitutions. The distinctly trace element distribution correlations (e.g., Mn, Se and Tl) of the studied pyrites indicate that they were formed in a high temperature and oxidizing environment. Low Au (1) and Se/Tl (>10) ratios of the studied pyrites imply that the Dongguashan deposit is most likely to be a magmatic-hydrothermal origin.

Seafloor hydrothermal chimneys are significant metal resources and have fundamental effects on marine chemistry balance. Previous studies on growth of the chimneys focused on mineral composition and elemental distribution in chimney walls, but the isotopic composition of different elements and their correlations remain poorly understood. Here, we report lateral Fe and S isotopes from sulfides across a chimney wall in detail from the Deyin-1 hydrothermal field (DHF) on the South Mid-Atlantic Ridge. Pyrite was characterized by increases in both δ34S and δ56Fe from the exterior to the interior within the chimney wall, which is likely related to enhanced S and Fe isotope fractionation between pyrite and fluids derived from the temperature gradient. Furthermore, δ56Fe displayed a well-defined, linear, positive correlation with δ34S in pyrite from the DHF as well as in pyrite from other areas. A model of hydrothermal pyrite formation suggests that, under conditions with uniform hydrothermal fluid, different temperatures and similar pyrite–fluid exchange degrees could result in the observed linear relationships between δ34S and δ56Fe. The regular and coupled Fe–S isotope variations within the chimney wall efficiently constrain the process of hydrothermal sulfide formation.

The westward subduction of the Pacific plate interacted with the northward subduction of the eastern Neo-Tethys plate in the Early Cretaceous. However, the subduction polarities between these two plates in the Early Cretaceous is not well constrained. The proto-Philippine arc is suggested to have originated at the Pacific – Neo-Tethys intersection in the SW Pacific in the latest Jurassic – Early Cretaceous, and can provide information about the ancient interaction between these two plates. In this study, the oldest known Early Cretaceous mantle-derived arc volcanic rocks and slab-melting generated adakites occurring in the Philippine arc have been studied for Pb, Sr, Nd and Hf isotopes to discriminate the provenance of their mantle sources and/or subduction components. The 126–118 Ma Kansi island arc volcanics have Pacific-type Pb isotopes, suggesting that the subduction components in the source are mainly from the subducted Pacific plate. Their Hf-Nd isotopes give support to a mantle source that is isotopically transitional Pacific-Indian type. The formation of the Kansi volcanics dates the subduction of the Pacific plate under the transitional Pacific-Indian mantle as Early Cretaceous. The subsequent generation of the 110 Ma Kansi adakitic diorites with the similar Pacific-type Pb isotopes indicates further partial melting of the subducted Pacific plate. In contrast, the post-110 Ma Lutopan adakitic diorites have Indian-type Pb isotopes, indicating the subsequent subduction of an Indian-type oceanic slab in the eastern Neo-Tethys tectonic regime. Therefore, the proto-Philippine arc is constrained to have originated at the intersection between Indian-type and Pacific-type oceanic crusts and mantle domains. The successive generation of these Early Cretaceous arc rocks in the Philippines indicates that a transformation of the tectonic regime from southwestward Pacific subduction to northeastward subduction of the eastern Neo-Tethys plate in the SW Pacific Ocean occurred at ca. 110 Ma, due to the abrupt change in drifting direction of the Pacific plate.

Supercritical CO2 appearing as bubbles in hydrothermal vents was identified in the south part of the Okinawa Trough using in situ Raman spectroscopy. Significantly, the N2 peak in supercritical CO2 is much larger than those in seawater and vent fluids, indicating that supercritical CO2 enriches N2 from the surrounding environment. Considering that the partial pressures of CO2 and N2 in the Earth’s proto-atmosphere were ~10–20 MPa, supercritical CO2 with high N2 was likely the dominant CO2 phase near the water-air interface in the early history of the Earth, which promoted the synthesis, pre-enrichment and preservation of amino acids and other organic matters that are essential to the origin of life.

In order to investigate the behavior of potassium (K) isotopes during metamorphic dehydration and to further constrain its implications for K recycling in the subduction zone, we measured K isotopic compositions of whole-rocks and separated minerals (phengite, omphacite, amphibole) from Sumdo eclogites, Tibet, using a recently established high-precision analysis method. Our data reveal that the δ41K (‰) of the whole-rock eclogites (−1.64 to −0.24) displays dramatically lower values than observed in fresh mid-ocean ridge basalts (MORB) (−0.43 ± 0.17) and altered MORB (−0.76 to −0.11). In addition, the δ41K values of eclogites show a positive correlation with both K2O contents and K/Nb ratios, which suggests that the low δ41K values were most likely caused by dehydration during subduction. Thus, isotopically heavy K may be released into the mantle wedge, while the light component is subducted into the deep mantle. Therefore, the K isotope systems have the potential to trace subducted crustal materials and to create heterogeneity within the mantle. Mineral separates from Sumdo eclogites are highly heterogeneous in K isotopic compositions, ranging from −0.98 to +0.23 in phengite, from −1.25 to −1.10 in omphacite and from −1.16 to −0.09 in amphibole. The K isotope fractionations between amphibole and phengite and between amphibole and omphacite vary from −0.30 to +0.25 and from −0.04 to +0.63, respectively, indicating K isotopic disequilibrium between amphibole and omphacite/phengite, which might result from the multistage growth of minerals during subduction metamorphism. However, generally phengites show heavier K isotopic compositions than the coexisting omphacite (Δ41Kphengite-amphibole = +0.25) and amphibole (Δ41Kphengite-amphibole = +0.03 ∼ +0.30, except TB193 is −0.25), which may imply that the K isotopic fractionation is controlled by the difference in coordination numbers of K between phengite (6) and omphacite (7 to 8)/amphibole (8).

Calcium isotopes can potentially be used to trace many geological processes. Characterizing the Ca isotopic compositions of marine sediments is a precondition for using Ca isotopes to trace the recycling of marine sediments into the mantle and mantle-derived rocks. The best way to achieve this goal is to investigate different types of marine sediments that are adjacent to subduction zones and would undergo subduction in the future. Here, we present high-precision Ca isotopic data for marine sediments from the Deep Sea Drilling Project (DSDP) Sites 543 and 144 along the Lesser Antilles forearc region, to constrain the Ca isotope signatures of marine sediments with various components and assess their possible effects on δ44/40Ca of the local mantle and arc lavas via subduction. Our results show that the δ44/40Ca values of these marine sediments vary from 0.10 to 1.21‰ and depend on lithology. Carbonate-rich sediments from Site 144 exhibit δ44/40Ca values in the range of 0.10–0.58‰ with a weighted average value of 0.36‰, which is ∼0.6‰ lower than that of the mantle. In comparison, δ44/40Ca of clay-rich sediments from Site 543 range from 0.79 to 1.21‰ with a mantle-like mean value of 0.96‰. The data obtained here suggest that carbonate- and clay-rich marine sediments differ significantly both in Ca isotopic compositions and CaO contents. Recycling of these sediments will result in different effects on the isotopic compositions of the local mantle and probably affect the local arc lavas. Specifically, carbonate-rich sediments from Site 144 with high CaO contents and light Ca isotopic compositions can alter the local mantle to lower δ44/40Ca signatures, which is expected in the southern Lesser Antilles arc lavas.

Subduction related metasomatism has been proposed to be one of the most important processes that may cause Ca isotopic heterogeneities in the mantle. Back-arc basin basalts (BABBs) affected by different contributions of subducted materials have various geochemical compositions ranging from MORB-like to arc-like, so that they are ideal media to investigate the behavior of Ca isotopes during plate subduction. Here we report Ca isotopic compositions of a series of BABBs from the Lau Basin, Woodlark Basin and Coriolis Troughs in the southwestern Pacific. Our results show that δ44/40Ca of all the BABBs exhibit a narrow range of 0.73 ± 0.07 to 0.89 ± 0.06‰ with an average of 0.80 ± 0.08‰ (2SD, N = 21), which are lower than the estimated value of the Bulk Silicate Earth (BSE, 0.94 ± 0.05‰), but are similar to that of MORBs reported in the literature (0.83 ± 0.11‰, 2SD, N = 21). Even though the mantle sources of BABBs studied here have been influenced by various amounts of slab-derived fluids and/or sediments, there is no systematic variation of δ44/40Ca with indicators of subduction contributions (e.g., Ce/Pb, Nb/U, Ba/La, Th/Yb, 87Sr/86Sr and 143Nd/144Nd). This suggests that either there is no Ca isotopic discrepancy between subducted components and mantle, and/or the amount of Ca that is transferred from the subducting Pacific slab to the studied BABB mantle sources is insignificant. Water depths at which subducting sediments were deposited control the components of marine sediments that may be subducted, which in turn determine how subduction affects Ca isotopic composition of the mantle. Because the southwestern Pacific has deeper water depths than the carbonate compensation depth, pelagic clays dominate the contribution from the subducted slab rather than carbonates, which leads to the negligible Ca isotopic fractionation during subduction along these trenches. The lack of correlations of δ44/40Ca with geochemical indicators of magma differentiation (e.g., MgO, CaO/Al2O3, Sr/Nd, Eu/Eu*) suggests that intermediate-mafic magma differentiation has insignificant effects on Ca isotopic compositions of BABBs. Therefore, we conclude that the observed offset of δ44/40Ca (∼0.14‰) between the mantle and BABBs studied here should be primarily controlled by Ca isotopic fractionation during partial melting without significant contributions from subducted materials.

2-furfuraldehyde (2-FAL) is widely accepted as a chemical marker to indicate the degradation of cellulose insulation in oil-impregnated transformers. However, the application of 2-FAL in the aging diagnosis of transformers in operation is ineffective. The excessive dispersion of 2-FAL concentration measured in transformers is caused by many influence factors. In addition, the 2-FAL concentration in oil cannot indicate the aging of the most serious point given the temperature distribution along the winding height, that is, the insulation at the hot spot of a winding. To optimize the assessment, an improved method for the hot-spot insulation assessment based on the 2-FAL concentration in oil is proposed in this work. The 2-FAL generation in cellulose chain scission is firstly analyzed theoretically, and a new linear relationship between ( 1 / D P t - 1 / D P 0 ) and 2-FAL total generation is obtained. Moreover, the 2-FAL partitioning between an insulation paper and mineral oil influenced by temperature, moisture, and aging status in total is considered. Second, by considering the linear relationship and the 2-FAL partitioning, an equation between the insulation at hot-spot temperature and the 2-FAL concentration in oil is established for the thermal aging under unequal temperature distribution condition. Finally, to verify the proposed method, a testing platform is introduced to conduct the thermal aging experiment with temperature gradients. The proposed method demonstrates better assessment results than the conventional thermal aging test at constant temperature.

Summary Large-scale shale gas exploitation greatly enriches ethane resources, making the oxidative dehydrogenation of ethane to ethylene quite fascinating, but the qualified catalyst with unique combination of enhanced activity/selectivity, enhanced heat transfer, and low pressure drop presents a grand challenge. Herein, a high-performance Nb2O5-NiO/Ni-foam catalyst engineered from nano- to macroscale for this reaction is tailored by finely tuning the performance-relevant Nb2O5-NiO interaction that is strongly dependent on NiO-precursor morphology. Three NiO-precursors of different morphologies (clump, rod, and nanosheet) were directly grown onto Ni-foam followed by Nb2O5 modification to obtain the catalyst products. Notably, the one from the NiO-precursor of nanosheet achieves the highest ethylene yield, in nature, because of markedly diminished unselective oxygen species due to enhanced interaction between Nb2O5 and NiO nanosheet. An advanced catalyst is developed by further thinning the NiO-precursor nanosheet, which achieves 60% conversion with 80% selectivity and is stable for at least 240 h., Graphical Abstract, Highlights • A series of Nb2O5-NiO/Ni-foam catalysts are developed for the ODE reaction • Catalysts are obtained by Nb2O5 modification of NiO-precursors grown onto Ni-foam • Thinning NiO-precursors dramatically improves the ethylene selectivity • Non-selective O2- species are markedly reduced with enhanced Nb2O5-NiO interaction, Catalysis; Organic Reaction; Nanomaterials; Nanostructure

Goose astrovirus (GAstV) is a novel pathogen that was discovered in 2018. It has two genotypes, GAstV-1 and GAstV-2, and both can cause visceral gout of goslings and result in significant economic losses. The present work aimed to develop a duplex TaqMan real-time quantitative reverse transcription PCR (RT-qPCR) assay to distinguish the two genotypes. MegAlign software was used to design two pairs of primers and a pair of matched probes based on the open reading frame 2 (ORF2) sequence with the greatest difference between GAstV-1 and GAstV-2, and primer and probe concentrations and annealing temperatures were optimised. Fluorescence signals were obtained for GAstV-1 and GAstV-2 in the FAM and VIC channels, respectively, but no fluorescent signal was observed for other pathogens. The detection limit for GAstV-1 and GAstV-2 was 33.3 and 33.7 DNA copies/μL, respectively. Intra- and inter-assay variability tests revealed excellent reproducibility. Furthermore, the assay detected GAstV-1 and GAstV-2 in allantoic fluids (100% positive) spiked with viruses, and 70 clinical gout gosling samples were examined, of which 11.4% were positive for GAstV-1, 74.3% were positive for GAstV-2%, and 5.7% were positive for mixed infection. In summary, the developed duplex RT-qPCR assay has high specificity, sensitivity, and reproducibility, and can be used in the clinic for detection of GAstV-1 and GAstV-2.

We present high-precision iron isotope data for harzburgites and constituting minerals from the Yushigou supra-subduction zone ophiolite in the North Qilian orogen of northern Tibet to provide insights into iron isotope behavior in subduction zones. The Yushigou harzburgites represent typical melting residues of silica-enriched forearc mantle wedge with significant melt extraction and minimal melt percolation. The δ56Fe ranges from −0.096‰ to 0.110‰ in olivine, from −0.111‰ to 0.105‰ in orthopyroxene and from −0.141‰ to 0.054‰ in spinel. Coexisting minerals fall on a line with a slope of 1 in the δ-δ plot, indicating iron isotope equilibrium between mineral pairs. Iron isotopic fractionation between olivine and orthopyroxene is minor, which is consistent with theoretical predictions and previous observations. Good iron isotopic equilibrium between olivine and orthopyroxene is a further indicator that silica enrichment in arc peridotites is inherited from their mantle source. In contrast, significantly negative iron isotopic fractionation between spinel and olivine contradicts with most previous constraints, which may be ascribed to Cr substitution in spinel. Bulk rock harzburgites have δ56Fe ranging from −0.097‰ to 0.076‰, the average of which (0.002 ± 0.020‰) is similar to average δ56Fe determined for abyssal peridotites. Based on this inference, the lower δ56Fe of arc magmas than MORB should be due to smaller discrepancy in Fe3+/ΣFe between arc magmas and arc peridotites when compared with MORB and abyssal peridotites. Our modelling demonstrates that this can be achieved if arc magmas are produced by redox-buffered melting of silica-enriched mantle wedge while MORB are produced by redox-unbuffered melting of the depleted mantle.

The Cu-Mo polymetallic deposits are widespread in the Chizhou region, the Middle and Lower Yangtze River metallogenic belt, eastern China, but the formation of Cu-Mo polymetallic deposits remains unclear. Geochronological, geochemical and Sr-Nd-Hf isotopic compositions of the Cu-Mo polymetallic deposits in the Chizhou region are systemically investigated to reveal the formation of Cu-Mo polymetallic deposits and petrogenesis of the granodiorite (porphyry). The geochronological dating results show the formation ages of Cu-Mo polymetallic deposits (molybdenite Re-Os age, 151–148 Ma) and the granodiorites (porphyries) (zircon U-Pb age, 150–146 Ma) in the Chizhou region are simultaneous (within error). The Chizhou granodiorites (porphyries) (SiO2 = 62.9–65.7 wt%) are high-K calc-alkaline peraluminous I-type granodiorites. They have high Mg# (mainly >40) values and low Na2O ( 0.2 wt%), and high log fO2 values (−28.3 to −6.22). The distinctly chemical and isotopic compositions indicate that the Chizhou granodiorites formed from metasomatized mantle-derived magmas mixing with Neoproterozoic crustal components. The results indicate that the formation of the Cu-Mo polymetallic deposits in the Chizhou region may depend on the slab-derived Cl-enriched fluids, an oxidizing environment and a mantle-crust mixed source.

Scheelite has been analyzed from the Shizhuyuan and the Xianglushan world-class W deposits from the Nanling W–Sn region and Jiangnan W belt, respectively. The Shizhuyuan deposit consists of proximal skarn and greisen W–Sn–Mo–Bi and distal Pb–Zn–Ag veins. The Xianglushan deposit, contains layer-like sulfide–scheelite and skarn W orebodies on granite cupolas overprinted by W greisen veins. Scheelite in skarn ores from the Shizhuyuan contains higher concentrations of Mo than those in the sulfide–scheelite and skarn ores from the Xianglushan deposit, reflecting differences between oxidizing and reducing magmatic-hydrothermal fluids. Under oxidizing conditions, W is accompanied by Mo partitions into exsolved fluids to form W–Mo garnet skarns, whereas under reducing conditions, little Mo is carried by exsolved fluids to form W pyroxene skarns. Trace element patterns of scheelite from both deposits show negative Ba, Sr, Zr, and Ti, and positive Ta anomalies. Rare earth element (REE)patterns of scheelite within skarns from the Shizhuyuan deposit have negatively inclined and flat M-type tetrad patterns, and scheelite from the greisens displays flat and positively inclined M-type tetrad patterns. We infer that the fluids formed scheelite within the W skarns and greisens inherited parental magma trace element and REE characteristics (depleted Ba, Sr, Zr, and Ti, enriched Ta, negative Eu anomalies, and tetrad effects). Whereas, scheelite from sulfide–scheelite veins and skarns of the Xianglushan deposit also has W- and MW-type tetrad REE patterns. The W-type tetrad REE patterns are complementary to REE patterns from the Renjiashan granite, and the MW-type tetrad REE patterns occur during a single evolutionary stage within a complex hydrothermal environment. Sulfide mineralization can form after or before W skarns (the former like Shizhuyuan deposit and the latter like Xianglushan deposit). The formation conditions of the latter included reducing conditions and sulfide firstly supersaturated in the melt, resulting in sulfide drops which carried W aggregated on the cupolas. W skarns and greisens in both deposits underwent generally successive processes related to water supersaturation in the melt. Following a temperature decrease and crystallization, bubbles carried material changing from Si and metal to Si oxide complexes.