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Under economic globalization, countries are linked through trade and investments. This economic interdependence creates vulnerabilities. The indirect vulnerability induced by interdependent networks of trade and investments can put a country's economy at risk, but this risk has yet to be systematically quantified and investigated. In this paper, we developed the novel Potential Indirect Vulnerability Index (PIVI) to capture how interdependencies between networks of trade and foreign direct investment (FDI) may induce economic vulnerabilities. The model consisted of three main components: a target country (the importer of goods), an investing country (the exporter of FDI), and the intermediary countries that export commodities to the target country and receive FDI from the investing country, serving as conduits of the vulnerabilities caused indirectly by the investing country. The PIVI quantifies the indirect vulnerabilities based on the product of two fractions: 1) the dependency of the target country on commodities from each intermediary country; and 2) the dependency of each intermediary country on FDI from the investing country. We demonstrated the utility of PIVI by examining the US economy's vulnerability to China using 2019 trade and FDI data. Several Asian countries and a mix of agricultural products and raw materials were identified as conduits through which China could potentially influence the US economy. Vietnam was a sizeable risk because, while it has been a primary source of many US imports, it also received about 30% of its FDI from China. The US policy makers might opt to increase diversity in trade partners or to promote investment in countries such as Vietnam. We also applied the PIVI analysis to critical minerals, identifying cobalt, tungsten, and copper as the most vulnerability-inducing among them. PIVI is a flexible metric than can be aggregated and modified to provide a more nuanced and focused assessment of an economy's vulnerability. [ABSTRACT FROM AUTHOR]

The Xingluokeng deposit is the largest granite-related tungsten deposit within the Wuyi metallogenic belt in South China. The Xingluokeng intrusion primarily consists of porphyritic biotite granite, biotite granite, and fine-grained granite. The deposit is represented by veinlet-disseminated mineralization with K-feldspathization and biotitization, alongside quartz-vein mineralization with greisenization and sericitization. This study investigates in-situ analyses of quartz compositions from both the intrusion and hydrothermal veinlets and veins. Trace element correlations indicate that trivalent Al3+ and Fe3+ replace Si4+ within the quartz lattice, with monovalent cations (such as Li+, Na+, and K+) primarily serving as charge compensators. Low Ge/Al ratios (< 0.013) of quartz from granites suggest a magmatic origin. The low Al/Ti and Ge/Ti ratios, accompanied by high Ti contents in quartz, suggest that the porphyritic biotite granite and biotite granite are characterized by relatively low levels of differentiation and high crystallization temperatures. In contrast, the fine-grained granite exhibits a higher degree of fractionation, lower crystallization temperatures, and a closer association with tungsten mineralization. Ti contents in quartz from quartz veins indicate Qz-I formed at temperatures above 400 °C, while Qz-II to Qz-V formed at temperatures below 350 °C. Variations in different generations of quartz, as indicated by Al content and (Al + Fe)/(Li + Na + K) ratio, suggest that Qz-I precipitated from a less acidic fluid with a stable pH, whereas Qz-II to Qz-V originated from a more acidic fluid with notable pH variations. Consequently, alkaline alteration and acidic alteration supplied the essential Ca and Fe for the precipitation of scheelite and wolframite, respectively, highlighting a critical mechanism in tungsten mineralization at the Xingluokeng deposit. [ABSTRACT FROM AUTHOR]

The ecological and human health risks of heavy metal(loid)s (HMs) in soils around tungsten (W) mining sites have often disregarded the presence of W. In this study, we aimed to investigate the concentrations of 10 HMs (including W and other accompanying elements) in 18 agricultural soil samples obtained around a W mining site in southern Jiangxi, China. Furthermore, we determined the contamination status, source identification, and ecological and health risks of HMs in soils. Our findings revealed that HMs were extensively accumulated in soils within the study area, with the highest mean concentrations of W found. W concentrations were above background values at all sites. Multivariate analysis revealed that W mining activities, including extracting and transporting W ore, were the primary source of HMs in the soil (61.40%). The ecological risk assessment revealed that the potential ecological risk across the survey area exhibited a high risk, and the cadmium (Cd) and W should be prioritised as control pollutants for soils around the W mine site. The human health risk assessment displayed that 73.43% of children with an unacceptable non-carcinogenic risk, and W contributed the most to the overall non-carcinogenic risk (42.32%), followed by Cd and arsenic (As). In addition, 22.03% of children and 13.4% of adults were under a significant carcinogenic risk. Overall, our findings emphasise the importance of considering element W in future studies investigating the contamination of HMs around W mining areas. As such, we calculated a safe limit value for element W in soil (141.01 mg/kg) to facilitate the conservation and development of soils in W mining areas in China. Our study provides valuable information for pollution prevention and soil contamination risk mitigation in W mining areas. [ABSTRACT FROM AUTHOR]

Background: Dayu County, a major tungsten producer in China, experiences severe heavy metal pollution. This study evaluated the pollution status, the accumulation characteristics in paddy rice, and the potential ecological risks of heavy metals in agricutural soils near tungsten mining areas of Dayu County. Furthermore, the impacts of soil properties on the accumulation of heavy metals in soil were explored. Methods: The geo-accumulation index (Igeo), the contamination factor (CF), and the pollution load index (PLI) were used to evaluate the pollution status of metals (As, Cd, Cu, Cr, Pb, Mo, W, and Zn) in soils. The ecological risk factor (RI) was used to assess the potential ecological risks of heavy metals in soil. The health risks and accumulation of heavy metals in paddy rice were evaluated using the health risk index and the translocation factor (TF), respectively. Pearson's correlation coefficient was used to discuss the influence of soil factors on heavy metal contents in soil. Results: The concentrations of metals exceeded the respective average background values for soils (As: 10.4, Cd: 0.10, Cu: 20.8, Cr: 48.0, Pb: 32.1, Mo: 0.30, W: 4.93, Zn: 69.0, mg/kg). The levels of As, Cd, Mo, and tungsten(W) exceeded the risk screening values for Chinese agricultural soil contamination and the Dutch standard. The mean concentrations of the eight tested heavy metals followed the order FJ-S > QL > FJ-N > HL > CJ-E > CJ-W, with a significant distribution throughout the Zhangjiang River basin. Heavy metals, especially Cd, were enriched in paddy rice. The Igeo and CF assessment indicated that the soil was moderately to heavily polluted by Mo, W and Cd, and the PLI assessment indicated the the sites of FJ-S and QL were extremely severely polluted due to the contribution of Cd, Mo and W. The RI results indicated that Cd posed the highest risk near tungsten mining areas. The non-carcinogenic and total carcinogenic risks were above the threshold values (non-carcinogenic risk by HQ > 1, carcinogenic risks by CR > 1 x 10-4 a-1) for As and Cd. Correlation analysis indicated that K2O, Na2O, and CaO are main factors affecting the accumulation and migration of heavy metals in soils and plants. Our findings reveal significant contamination of soils and crops with heavy metals, especially Cd, Mo, and W, near mining areas, highlighting serious health risks. This emphasizes the need for immediate remedial actions and the implementation of stringent environmental policies to safeguard health and the environment. [ABSTRACT FROM AUTHOR]

The Nanling region is located at the intersection of the Yangtze Block and Cathaysia Block and is characterized by complex geological and tectonic processes, as well as distinct W-Sn-REE mineralization. Despite extensive research on the mineralization of W-Sn and REE deposits in the Nanling region, the factors impacting the distribution pattern of eastern tungsten and western tin deposits, as well as the mechanism of REE enrichment in the parent rocks, remain uncertain. Deep structural and tectonic variability plays a crucial role in the formation of mineral deposits in the upper crust. Information on deep structural and tectonic variability is contained in the Moho depth, Curie depth, effective elastic thickness, lithospheric density, and thermal structure derived from the processing and inversion of satellite gravity and magnetic data. In this paper, we comprehensively analyse satellite gravity and magnetic data from the Nanling region, integrating the processing and inversion results with the tectonic evolution of this region and relevant geological information. It is hypothesized that the Chenzhou–Linwu fault serves as a channel for mineral and thermal transfer in the Sn ore aggregation zone, facilitating the material transport from the deep mantle to the surface and ultimately leading to the formation of Sn-enriched granite. The collection area of tungsten ore is more weakly associated with the Chenzhou–Linwu fault, and through deep heat transfer, tungsten components are primarily concentrated in the Earth's crust to produce W-enriched granite. The primary source of REE enrichment in the parent rocks associated with REE mineralization is predominantly derived from the felsic crust, and the rapid intrusion of deep magma resulting from the subduction and retraction of the Palaeo-Pacific Plate is a contributing factor to the contrasting enrichment of light and heavy rare-earth elements. Mineral crystalline differentiation is relatively high, leading to the formation of ore-forming parent rocks with high heavy rare-earth element contents. [ABSTRACT FROM AUTHOR]

Accurately determining the timing and mechanism of metallogenesis of ore deposits is essential for developing a robust genetic model for their exploration. In this paper, we analyze the formation conditions of cassiterite in five major deposits of southern Hunan Province, one of the most important tungsten-tin (W-Sn) provinces in South China, using a combination of cathodoluminescence imaging, in situ U-Pb geochronology, and trace-element concentration data. In situ cassiterite U-Pb geochronology constrains the main period of Sn mineralization to between 155.4 and 142.0 Ma, demonstrating a temporal and genetic relationship to silicic intrusive magmatism in the same area. Three stages of magmatic activity and metallogenic evolution are recognized: (1) Early Paleozoic and Triassic: the initial enrichment stage of tungsten and tin; (2) Jurassic: the metasomatic mineralization stage; and (3) Cretaceous: the magmatic-hydrothermal superposition stage. The cassiterite in these deposits takes four forms, i.e., quartz vein-type, greisen-skarn-type, greisen-type, and granite-type, representing a progression characterized by the increasing content and decreasing range of variation of high field strength elements (HFSEs), and reflecting a general increase in the degree of evolution of the associated granites. Rare earth element (REE) concentrations suggest that precipitation of cassiterite was insensitive to the redox state of the fluid and that precipitation of cassiterite in the southern Hunan Sn deposits did not require a high-fO2 environment. These findings provide new insights into tin mineralization processes and exploration strategies. [ABSTRACT FROM AUTHOR]

The Nanling metallogenic belt in South China hosts ∼50 percent of the world's tungsten (W), ∼20 percent tin (Sn), and other critical metals. However, the factors controlling ore distribution and types are still debated, due partly to the lack of high‐resolution crustal models. We apply an array‐based receiver function imaging method to resolve the fine‐scale crustal structure using a newly deployed dense nodal array across the belt. We find weak Moho converting phases in the northern belt, indicating a gradual crust‐mantle transition distinct from the sharp transitions observed elsewhere. The weak Moho spatially correlates with a major fault zone, A‐type granite distribution, and Sn ore deposits. Combining with geochemical and petrological evidence, we propose that the gradual crust‐mantle transition is attributed to, and likely facilitated, the mixing of mantle materials with the crust, thus contributing to Sn and other Mesozoic ore formations in the northern Nanling belt. Plain Language Summary: Mapping the detailed crustal structure plays a critical role in ore characterization and exploration, which is essential to keep pace with societal needs for green energy and sustainability. Here we apply seismic imaging to delineate the subsurface structure of the Nanling metallogenic belt in South China using hundreds of sensors. We find the crustal structure, particularly the Moho geometries, spatially correlates with the types of ore deposits. Specifically, the tin and tungsten‐tin‐bearing granites that have mantle chemical signatures are distributed near a major fault zone with a gradual crust‐mantle transition. In contrast, tungsten and other metal deposits in the central belt show evidence of mostly crustal origin with a seismically sharp and elevated Moho. We propose that the imaged gradual crust‐mantle transition, which corresponds likely to an inherited lithospheric weak zone, could serve as a magmatic pathway for mantle materials to flux into the lower crust, thus contributing to critical ore deposits. Key Points: We apply receiver function imaging using a dense nodal array to the largest metallogenic belt in South ChinaWe observe weak Moho converted phases near a major fault zone and an uplifted Moho by ∼4 km in the central metallogenic beltThe obtained crustal structure correlates spatially with the characteristic geochemical signature of the ore deposits [ABSTRACT FROM AUTHOR]

The current study aims at assessing the capabilities of five machine learning models in terms of mapping tungsten polymetallic prospectivity in the Gannan region, China. The five models include logistic regression (LR), support vector machine (SVM), random forest, convolutional neural network (CNN), and light gradient boosting machine (LGBM) models. Three types of data sets including geochemical data, lithostratigraphic contacts, and faults were employed to generate 16 evidential maps that were used to build the machine learning models. Tungsten polymetallic deposits were randomly separated into two parts: 80% for training and 20% for validating. Performance of the models was evaluated through receiver operating characteristic and K‐fold cross validation, with an emphasis on the variable influence within different machine learning methods. The results show that the models are especially sensitive to the chemical elements: Be, Bi, Pb, and Cd, implying that they are closely related to tungsten polymetallic mineralization. Compared to other models, the LGBM and CNN models performed best, while the LR model was the most stable. The results also indicated that the CNN model can predict the maximum number of tungsten polymetallic deposits within the minimum area based on the prediction‐area plot analysis, while the SVM model can capture the least amount of tungsten polymetallic deposits within the largest area. Finally, 18 prospective areas were delineated according to the prediction results of the machine learning models, which provided important guidance for tungsten polymetallic exploration in the study area. Key Points: Five machine learning models were used and compared for tungsten polymetallic prospectivity analysis in the Gannan region, ChinaPerformances of the machine learning models were evaluated through receiver operating characteristic, P‐A plot, and K‐fold cross validationConvolutional neural network model is most efficient in mapping favorable areas for tungsten polymetallic exploration [ABSTRACT FROM AUTHOR]

Skarn-type tungsten deposits are widely distributed all over the world and contribute more than 70% of the world's W supply. The temporal relation between the W mineralization and causative intrusions and the evolution of ore-forming fluids are matters of ongoing debate. In this study, we combine in situ LA-ICP-MS U-Pb dating and trace element compositions of scheelite from Zhuxi, the world's largest W deposit, and compare them with literature data to address the above issues. Three primary ore stages exist at Zhuxi: prograde skarn, retrograde skarn, and quartz-sulfide stages. Most scheelite occurs in the retrograde skarn stage and is further subdivided into three generations: Sch A, B, and C. The obtained LA-ICP-MS U-Pb ages for three scheelite generations in the Zhuxi deposit are 154.0 ± 2.8, 150.3 ± 3.5, and 150.4 ± 6.3 Ma, respectively, indicating that the entire W mineralization is closely related to the emplacement of the nearby Late Jurassic granites (~154 to 150 Ma, zircon U-Pb ages). In situ LA-ICP-MS trace element results demonstrate that Sch A shows the highest Mo content (mean = 1002 ppm), where those for Sch B and Sch C are 109 and 45 ppm, respectively. These, combined with the gradually increasing trend of Ce contents and δCe values, indicate a shift from oxidizing to reducing conditions for the ore-forming fluid. All three scheelite generations yield significant positive δEu anomalies, which are considered to be unrelated to the redox state, but caused by the addition of Eu (e.g., feldspar dissolution). The high-Y/Ho ratio of scheelite and a good correlation between Y/Ho ratio and δEu (R2 = 0.96) suggest that intense fluid-rock interactions between ore fluids and the Shuangqiaoshan Group metasedimentary rocks as well as earlier-formed skarns drove fluid evolution. This study demonstrates that scheelite U-Pb geochronology is a useful technique when identifying the temporal link between hydrothermal W mineralization and the causative intrusion. Our results also highlight that the reactions of the ore fluids with wall rocks and earlier-formed skarns significantly modify the primary fluid compositions. [ABSTRACT FROM AUTHOR]

As a metal of strategic value, tungsten plays an important part in civil and military applications. Currently, China is the biggest tungsten producer all over the world, and the metallic smelting technologies for tungsten are well established. However, the harmless recovery and treatment procedures for tungsten residue remain rather underdeveloped. The treatment of tungsten residue generally includes the recovery of valuable metals (e.g., scandium, tantalum, and niobium) and the solidification of toxic elements (e.g., arsenic, lead, and chromium), which may control the transfer of these elements and metals. If treated improperly, the resource of tungsten residue may be wasted, and potential environmental risks could arise. Therefore, the safe disposition of tungsten residue has become the limit factor and an urgent problem to be solved for the sustainable development of tungsten-related industries. In this regard, we reviewed the industrial background of tungsten and the composition and toxicity characteristics of tungsten residue. In addition, particular attention was paid to the harmless utilization processes and technologies for tungsten residue, which were then systematically compared in terms of the applicable situations as well as their advantages and shortcomings. Finally, the development trend for the harmless utilization of tungsten residue was discussed, and some proposals for further studies were provided. [ABSTRACT FROM AUTHOR]

The Yangchuling porphyry W–Mo deposit is an oxidized tungsten deposit in the Jiangnan tungsten belt, which is the largest tungsten belt in the world. Both W- and Mo-mineralization predominantly occur in the cupola of a monzogranite porphyry with abundant mafic dikes and microgranular mafic enclaves (MMEs). Acicular apatite in MMEs and similar SIMS U–Pb zircon ages of the monzogranite porphyry (149.7 ± 1.1 Ma) and MMEs (148.7 ± 1.3 Ma) suggesting mixing of mafic and felsic melts. Plagioclase phenocrysts are oscillatory zoned with An-rich and An-poor zones with lower 87Sr/86Srinitial values and higher contents of Mg, Ti, and Sr in the An-rich zones and resorption surfaces in An-poor bands. These textures reflect multiple injection of mafic magma into the magma system responsible for the formation of the Yangchuling deposit. Whole rock Sr–Nd isotope data and zircon Hf–O isotope data indicate 60–70% contribution from the enriched mantle and 30–40% from the crust to the ore-forming granitic rocks. The W and Mo endowments of the Yangchuling deposit and other W-Mo deposits in the Jiangnan tungsten belt have different sources. Whereas W is derived from the melting of supracrustal metasedimentary rocks, Mo is contributed by mafic magmas. The latter is inferred from (i) the close relationship of Mo mineralization with mafic dikes and MMEs rather than the more evolved monzogranite porphyry and (ii) higher Mo concentrations in scheelite from MMEs (3020–3406 ppm) than in scheelite from the host monzogranitic porphyry (540–1886 ppm). On the scale of the whole Jiangnan tungsten belt, granitic rocks with more intense Mo mineralization have higher εHf zircon values that demonstrate higher input of mantle material to the deposit-forming granites. [ABSTRACT FROM AUTHOR]

The formation and evolution of the ancient continental crust are crucial issues in solid-earth geology which are commonly associated with global tectonic events and the formation of economically valuable magmatic-hydrothermal ore deposits. The Cathaysia Block, one of the ancient continents in Southeast Asia, can be subdivided into two parts: the West Cathaysia Block and the East Cathaysia Block. Unlike the East Cathaysia Block, no Precambrian rocks are exposed in the West Cathaysia Block, constraining further understanding of the formation and evolution of this block. In this study, a total of four hundred and thirty-three zircon U-Pb dating analyses and two hundred and eighteen Lu-Hf isotopic analyses on zircon grains from the Jurassic Dengfuxian granites and Ordovician Tanghu granites, Nanling Range, were carried out. LA-ICP-MS zircon U-Pb dating yields mean average 206Pb/238U ages of 152.6 ± 2.2 Ma (MSWD = 1.6) and 442.4 ± 1.7 Ma (MSWD = 3.8), which are regarded as the rock-forming age for the Jurassic Dengfuxian granites and Ordovician Tanghu granites, respectively. The 207Pb/206Pb ages of the inherited zircons from the Jurassic Dengfuxian granites and Ordovician Tanghu granites range from 522 Ma to 3395 Ma, hosting two major peaks at the 0.9–1.0 Ga and 2.4–2.5 Ga. In contrast to the East Cathaysia Block, the West Cathaysia Block lacks the age peak of 1.8–1.9 Ga, indicating that the West Cathaysia Block was not influenced by the assembly of the Columbia supercontinent in the Paleo-Proterozoic. In combination with the Lu-Hf isotopes, we proposed that the crust evolution of the West Cathaysia Block in Archean is dominated by juvenile crustal growth events, and dominated by the crustal reworking since the Proterozoic. The long duration of crustal reworking in the West Cathaysia Block resulted in the enrichment of lithophile elements (e.g., W, Sn, Nb, and Ta) in the crust of that region. Therefore, the Jurassic granites in the Nanling Range, which are mainly derived from the partial melting of Proterozoic basement rocks, became associated with large-scale tungsten polymetallic mineralization. [ABSTRACT FROM AUTHOR]

Revealing hydrothermal evolution from the early oxide to late carbonate stages for quartz–wolframite vein‐type deposits is essential for understanding the ore‐forming process. In this study, we choose the Baishitouwa tungsten polymetallic deposit located in the southern Great Xing'an Range tungsten belt as a case study, and present detailed deposit geology and in situ fluid inclusion (FI) analyses including microthermometry, laser Raman spectra, and LA‐ICP‐MS microanalysis to address this issue. Four stages of hydrothermal activity were identified: (1) quartz–wolframite (I), (2) quartz–wolframite (II)–pyrite–chalcopyrite, (3) quartz–polymetallic sulphides, and (4) quartz–carbonate. Four types of FIs were recognized: CO2‐rich, CO2‐bearing, liquid‐rich, and brine inclusions. Microthermometric data showed that the homogenization temperatures and salinities from the early to late stages are 380–460°C, 7.4–17.3, and 29.3–43.2 wt% NaCl equiv., 300–390°C and 7.1–17.0 wt% NaCl equiv., 220–320°C and 2.7–8.1 wt% NaCl equiv., and 150–250°C and 0.5–4.8 wt% NaCl equiv., respectively, suggesting a decreasing trend. Geochemically, all stage fluids contained high Rb and Mn concentrations, high Rb/Na, Cs/Na, Li/Na, K/Na, Rb/Sr, low K/Rb, and consistent Cs/Rb and Cs/(Na + K) ratios, indicating that the mineralizing fluids originated from a common source—an underlying, geochemically uniform, and highly fractionated granitic magma. Fluid immiscibility and cooling are the main mechanisms for wolframite precipitation, whereas greisenization is subordinate; the incursion of meteoric water into the hydrothermal system initiated at the sulphide stage, and fluid mixing is the dominant mechanism for sulphide precipitation. [ABSTRACT FROM AUTHOR]

The Banjing tungsten deposit, which has been discovered recently, is located in the northernmost part of the Dabu pluton, southern Jiangxi Province, China. In this study, zircon LA‐ICP‐MS U–Pb dating of the fine‐grained porphyritic biotite granite indicate that it was formed in the early Yanshanian (159.4 ± 2.5 Ma–161.6 ± 0.8 Ma). Whole‐rock geochemical studies have shown the fine‐grained porphyritic biotite granite has SiO2 of 75.82%–76.84%, Al2O3 12.50%–12.87%, MgO 0.07%–0.20%, and CaO 0.64%–1.09%, with A/CNK of 1.017–1.038. It has a total rare earth elements content of 93.9–118.9 ppm with strong negative Eu anomalies (δEu = 0.021–0.081). The biotite granite is enriched in Rb, Th, U, Nd and depleted in Ba, Sr, Nb, Ti. These data suggest the Dabu pluton belongs to S‐type granite. This pluton has ISr of 0.71212–0.72929 and εNd(t) from −9.60 to −10.62 with Nd model ages concentrated in 1732–1838 Ma. These isotopic data in combination with zircon Hf isotopes suggest the biotite granite originated from partial melting of the Middle Proterozoic metamorphic supracrustal rocks in South China, with a minor contribution from juvenile crust. Meanwhile, this study has obtained Re–Os isochron ages of the intrusion‐related and quartz vein‐type molybdenum mineralization are 156.3 ± 2.7 Ma and 157.0 ± 1.1 Ma in the Banjing tungsten deposit, respectively. Sericite from the greisen‐type tungsten‐molybdenum ore has an 40Ar–39Ar plateau age of 156.4 ± 1.0 Ma, interpreted as the formation age of this deposit. Collectively, the Banjing tungsten deposit is considered as a product of the early Yanshanian large‐scale peak mineralization in South China, which was formed in an extensional intracontinental environment caused by the subduction of the Palaeo‐Pacific Plate. [ABSTRACT FROM AUTHOR]

The Huashandong W deposit (7.7 Mt @ 0.26% WO3) is a newly discovered Neoproterozoic scheelite-dominated deposit in the world-class Jiangnan tungsten belt, South China. It occurs largely in metasedimentary rocks near the western margin of the Neoproterozoic Jiuling batholith and mainly consists of W-bearing exogreisen, hydrothermal breccias, and quartz veins. Two episodes of Neoproterozoic granite magmatism are identified with zircon U-Pb ages of ca. 830–823 and 807–804 Ma, respectively. According to cross-cutting relationships and mineral assemblages, two periods of hydrothermal alteration and W mineralization, corresponding to the two episodes of granite magmatism, are recognized in the Huashandong deposit. The early period is dominated by greisenization and associated scheelite mineralization whereas the late period is characterized by sericitization, hydrothermal brecciation, quartz veining, and associated scheelite and minor wolframite mineralization. Molybdenite Re-Os dating indicates that the early- and late-period W mineralization took place at ca. 828 and 800 Ma, respectively. Zircon trace element characteristics suggest that the Jiuling granite crystallized from reduced granitic magmas and has the potential for W mineralization. The petrologic and geochemical features of the Jiuling granite, coupled with the zircon U-Pb ages and Hf isotopic signatures and molybdenite Re-Os ages, imply that the Huashandong W deposit is genetically related to two phases of evolved granodiorites in the Jiuling batholith. The magmatic-hydrothermal nature of both metallogenic events is confirmed by H-O isotopes on hydrothermal quartz. [ABSTRACT FROM AUTHOR]

The Xihuashan and Yaogangxian granitic plutons in South China comprise highly evolved multiphase Li‐rich granites and host quartz‐vein‐type tungsten deposits. The δ7Li values of Phase A (early stage), B (middle stage), and C (late stage) from the Xihuashan pluton are 1.0–1.2‰, 1.1–3.0‰, and 2.4–2.8‰ respectively, increasing through chemical evolution. The granites from the Yaogangxian pluton also display gradually enriched in heavy Li isotopes in a later stage, although systematically lighter than those of the Xihuashan pluton. In both plutons, the δ7Li shows good correlations with SiO2 and Li concentrations as well as Rb/Sr, Nb/Ta, and Zr/Hf ratios, indicating Li isotopic fractionation most likely caused by magmatic differentiation. In situ analyses show that the minerals of Xihuashan pluton record a continuous elemental spectrum, reflecting the results of progressive magmatic differentiation. The δ7Li values of quartz, feldspar, mica, and zircon all correlate well with the chemical evolutions of granitic magma, systematically elevated in Phases B and C relative to Phase A. The Li isotope data of the mineral separates further document that the enrichment of 7Li in the residual melt was most likely due to the equilibrium fractionation between the mineral and melts. The data are interpreted to reflect that intense magmatic differentiation was responsible for Li isotopic variations coupled with the enrichment in the Li, F, P, and rare metals in the late‐phase granites of the Xihuashan pluton. The lithium isotope behavior documented in this study provides new insights into magmatic differentiation and associated rare‐metal mineralization. Plain Language Summary: In the past, magmatic differentiation was thought not to produce resolvable Li isotopic fractionation based on studies of basaltic rocks. Overall, only sparse studies on Li isotopes of highly evolved granites have been reported, and thus possible isotope fractionation of Li isotopes during differentiation of felsic magma could have been neglected. In this study, we present evidence of Li isotope fractionation during the differentiation of granitic magma. The most evolved (late‐stage) rare‐metal‐rich granites are systematically enriched in heavier Li isotopes. The chemical and isotopic compositions of both bulk rocks and mineral separates (e.g., zircon and mica) indicate that equilibrium fractionation during fractional crystallization governs Li isotopic behavior and enriches heavier Li isotopes in the residual melts. Our quantitative modeling also supports the equilibrium fractionation between minerals and magma as the primary mechanism for the observed Li isotopic variations. Key Points: Large Li isotopic fractionations are observed in rare‐metal‐rich peraluminous granitesFractional crystallization governs Li isotopic behavior and enriches heavier Li isotopes in the highly evolved granitesLithium isotopes provide new insights into the granitic magmatic differentiation process and rare‐metal mineralization [ABSTRACT FROM AUTHOR]

The Shamai tungsten deposit is located in the western part of the Xing'an Mongolian orogenic belt of northeastern China and contains quartz‐vein hosted tungsten mineralization. In this paper, we present the results of zircon laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) U–Pb dating of the fine‐grained biotite monzogranite, medium‐grained biotite monzogranite, and porphyritic biotite monzogranite samples from the deposit as well as in situ zircon Hf isotopic and in situ plagioclase Pb isotopic analyses. Combining new laser Raman spectroscopic data for fluid inclusions with previously HO isotopic data yields insights into the precipitation of ore minerals. The fine‐grained biotite monzogranite, medium‐grained biotite monzogranite, and porphyritic biotite monzogranite were emplaced at 142.5 ± 1.0 Ma, 141.9 ± 1.1 Ma, and 140.2 ± 1.0 Ma, respectively. The fine‐ to medium‐grained biotite monzogranite and porphyritic biotite monzogranite samples contain zircons with εHf(t) values from 3.2 to 7.9 and from 4.2 to 7.6, respectively, yielding tDM2 model ages from 996 to 692 Ma and 923 to 708 Ma, respectively. The geochemical, zircon Hf isotopic, and in situ plagioclase Pb isotopic data indicate that the magmas were generated by the partial melting of juvenile crustal material mixed with mantle‐derived components. The laser Raman and HO isotopic data for fluid inclusions within tungsten‐bearing quartz veins indicate that the tungsten mineralization formed as a result of fluid mixing. Combining the data with the spatial and temporal distribution and tectonic setting of tungsten deposits in NE China suggests that this area records four stages of mineralization at 300–290, 250–230, 200–180, and 150–130 Ma. The Shamai deposit occurred in an intra‐continental extensional regime. [ABSTRACT FROM AUTHOR]

[Display omitted] • First accuracy age of Neoproterozoic tungsten mineralization (ca. 826–818 Ma) in western Yangtze Block (WYB). • The Huili scheelite deposit is genetically related to the ca. 826 Ma highly fractionated granite. • Heterogeneous magma sources and highly differentiation account for the formation of W-mineralized granite. • Neoproterozoic tungsten mineralization in WYB may occur in an arc-related extensional setting. Neoproterozoic granitic magmatism and associated mineralization in the western Yangtze Block (WYB), South China, records the assembly and breakup of the Rodinia supercontinent, making it a key window for understanding the tectonic evolution and associated dynamic process of the Rodinia supercontinent. In this paper, we present an integrated study on petrology, petrography, geochemistry, zircon U-Pb-Hf isotope, vesuvianite U-Pb and muscovite Rb-Sr geochronology for the W-rich granitic plutons (Xiacun and Shunhe plutons) and ore-bearing granitic dikes from the newly discovered Neoproterozoic Huili tungsten deposit in the WYB. Our objective is to provide vital constraint on the mineralization age and metallogenic geodynamic setting of the Neoproterozoic Huili tungsten deposit in the WYB. The ore body is characterized by skarn-type and quartz vein-type mineralization with main ore mineral of scheelite and gangue minerals of vesuvianite, muscovite and diopside. Zircon U-Pb dating indicates the granitic plutons and granitic dikes emplaced at ca. 845 Ma and 824 Ma, respectively. The vesuvianite U-Pb age and muscovite Rb-Sr isochron age are ca. 826–818 Ma and 822 Ma, respectively, indicating the tungsten mineralization was coeval with the crystallization of the granitic dikes. Petrology and geochemical studies reveal that the granitic dikes and the Shunhe pluton are highly fractionated S-type granite, while the Xiacun pluton belongs to unfractionated S-type granite. The granitic plutons have uniform and weakly enriched zircon Lu-Hf isotopes (εHf(t) = -3.08 ∼ -0.22), while the granitic dikes have varied zircon Hf isotopes (εHf(t) = -10.57 ∼ 4.64). Zircon Lu-Hf isotopes, as well as their varied whole-rock geochemical compositions, indicate that the Xiacun and Shunhe granitic plutons mainly originate from partial melting of Middle Paleoproterozoic crust, while the ore-bearing granitic dikes are mainly derived from the melting of heterogeneous Middle Paleoproterozoic crust, followed by significant fractional crystallization of feldspar, biotite and accessory minerals. Petrological, geochronological and geochemical data compilation reveals that the studied ca. 845 Ma granitic plutons and ca. 824 Ma W-mineralized granitic dikes were formed in a progressive subduction and a back-arc extension setting, respectively, and the Neoproterozoic back-arc extension-related granitic magmatism during the breakup of Rodinia supercontinent may be beneficial for the tungsten mineralization. [ABSTRACT FROM AUTHOR]

The economically important tin‑tungsten mineralization in southwestern China has attracted much interest in recent years, yet its age, tectonic setting, and genetic relationship to the host granites remain uncertain in most regions. Our focus in this study is the Shuicheng tin-polymetallic deposit, situated in the western sector of the Diantan Batholith, within the northern Tengchong Block. The granites in this area consist of two intrusive units, i.e., 1) biotite monzogranite (T1), with LA-ICP-MS zircon U Pb ages ranging from 76.88 ± 0.43 Ma to 74.69 ± 0.57 Ma, whole-rock ε Nd (t) values ranging from −9.75 to −8.11, and zircon ε Hf (t) values from −12.19 to −8.85; and 2) alkali-feldspar granite (T2), with an LA-ICP-MS zircon U Pb age of 52.16 ± 0.23 Ma, whole-rock ε Nd (t) values of −10.15 to −8.25, and zircon ε Hf (t) values of −9.64 to −8.06. These two intrusive events have been linked to prolonged low-angle subduction and retreat of the subducting Neo-Tethys Ocean Plate, respectively. The Shuicheng granites exhibit high concentrations of SiO 2 and Al 2 O 3 , contrasted with low levels of FeOT, CaO, MgO, TiO 2 , and P 2 O 5 , suggesting that they are highly fractionated S-type granites. High abundances of Rb, K, U, and Hf, along with low contents of Ba, Sr, and Ti, further indicate significant fractionation and crystallization processes during magma evolution. Importantly, a transition from purely magmatic conditions to a magmatic-hydrothermal state occurred during the latter stages of magmatic evolution. This transition, associated with an amplified potential for tin mineralization, provides fresh insight into the role of magmatic processes in ore genesis, enriching our understanding of the tin‑tungsten mineralization history of the Tengchong region. [Display omitted] • The Shuicheng granites at Tengchong are highly differentiated S-type granite. • The Shuicheng granites were emplaced at 75–52 Ma by two stages of magmatism. • The magmas were related to the subduction and roll back of the Neo-Tethys Ocean. • The transition from melt to fluid serves as a sign of mineralization in the area. [ABSTRACT FROM AUTHOR]

The Zuluhong quartz-vein-type polymetallic deposit, located in the Alatau area of Western Tianshan, China, is a particular and typical tungsten deposit associated with copper. This paper presents major and trace element analyses of magmatic and altered (i.e, chloritized) biotite from the deposit, in order to identify the source of the magmas and characterize the mineralization physical-chemical condition. Magmatic biotite is Fe-rich and has high Rb/Ba ratios (0.27–9.14), indicative of extensive differentiation of granite. Moreover, magmatic biotite has total rare earth element (∑REE) contents that are 5–10% of the whole-rock contents, shows slight light REE depletion, and negative Ce anomalies. Magmatic biotite is enriched in some large-ion lithophile elements (LILE; e.g., Rb and K) and depleted in some high-field-strength elements (HFSE; e.g., Th and Nb). These geochemical features, coupled with geological evidence, indicate that the Zuluhong intrusion is a highly fractionated I-type granite derived from lower crustal melting. During ore formation, magmatic biotite was partially to totally altered to chlorite due to interaction with ore-forming fluids. The temperature and oxygen fugacity decreased during alteration. The mineralization in the Zuluhong polymetallic deposit can be divided into at least two stages. In the early stage, quartz-vein-type wolframite mineralization formed from Si- and volatile-rich fluids that were derived from fractionated granitic magma. In the later stage, W–Cu ores formed as metal sulfides were dominated by chalcopyrite. The later ore-forming fluids experienced a decrease in temperature and oxygen fugacity as they reacted (i.e, chloritization and lesser silicification) with reducing wall rocks around the contact zone of the intrusion. [ABSTRACT FROM AUTHOR]

The Piaotang deposit is one of the largest vein‐type W‐polymetallic deposits in southern Jiangxi Province, South China. The coexistence of wolframite and cassiterite is an important feature of the deposit. Based on detailed petrographic observations, microthermometry of fluid inclusions in wolframite, cassiterite and intergrown quartz was undertaken. The inclusions in wolframite were observed by infrared microscope, while those in cassiterite and quartz were observed in visible light. The fluid inclusions in wolframite can be divided into two types: aqueous inclusions with a large vapor‐phase proportion and aqueous inclusions with a small vapor‐phase ratio. The homogenization temperature (Th) of inclusions in wolframite with large vapor‐phase ratios ranged from 280°C to 390°C, with salinity ranging from 3.1 to 7.2 wt% NaCl eq. In contrast, the Th values of inclusions with small vapor‐phase ratios ranged from 216°C to 264°C, with salinity values ranging from 3.5 to 9.3 wt% NaCl eq. Th values of primary inclusions in cassiterite ranged from 316°C to 380°C, with salinity ranging from 5.4 to 9.3 wt% NaCl eq. Th values for primary fluid inclusions in quartz ranged from 162°C to 309°C, with salinity values ranging from 1.2 to 6.7 wt% NaCl eq. The results show that the formation conditions of wolframite, cassiterite and intergrown quartz are not uniform. The evolutionary processes of fluids related to these three kinds of minerals are also significantly different. Intergrown quartz cannot provide the depositional conditions of wolframite and cassiterite. The fluids related to tungsten mineralization for the NaCl‐H2O system had a medium‐to‐high temperature and low salinity, while the fluids related to tin mineralization for the NaCl‐H2O system had a high temperature and medium‐to‐low salinity. The results of this study suggest that fluid cooling is the main mechanism for the precipitation of tungsten and tin. [ABSTRACT FROM AUTHOR]

The ore-related Sn granites in the Youjiang basin (YJB; ~ 4.0 Mt Sn) and W granites in the Jiangnan tungsten belt (JNB; ~ 6.0 Mt WO3) in south China were studied to decipher regional-scale controls on whether Sn or W is most likely to be associated with highly fractionated reduced granitic magmas. Both Sn and W mineralization-related magmas were derived from partial melting of metasedimentary rocks. Although Sn and W behave similarly during fractional crystallization and therefore become enriched in highly evolved reduced granites, there is commonly a clear distinction between Sn-dominated and W-dominated systems. For example, the YJB hosts world-class Sn deposits that lack accompanying economic W, whereas the JNB hosts world-class reduced W deposits that lack accompanying economic Sn. This difference may be related to conditions of source melting, such that W is mobilized into initial granitic magmas when partial melting of metasedimentary rocks occurs at lower temperature, whereas melts that form at higher temperature may have higher Sn concentrations. The later have low W concentrations because W has already been lost at the lower temperature melting event. Results from this study reveal that the W-related granites in the JNB were derived from metasedimentary rocks that had never experienced a previous episode of high-grade metamorphism or melting. The melts were enriched in W but depleted in Sn and formed W-only ores after extensive fractional crystallization. In contrast, the granites in the YJB were derived from melting of metasedimentary rocks that had undergone previous episodes of high-grade metamorphism or melting and formed Sn-only ores after extensive fractional crystallization. [ABSTRACT FROM AUTHOR]

The Xintianling tungsten deposit is a super-large deposit in the Nanling tungsten–tin mineralization belt, which is genetically associated with the early-stage hornblende-biotite monzonitic granite of Qitianling pluton. The orebodies predominantly occur as veins and lenses within skarn rocks between Xintianling granite and limestone (Shidengzi group). In this work, whole-rock major and trace elements and zircon U–Pb ages of the Xintianling granite were studied in an attempt to investigate the geochronological framework, petrogenesis, tectonism, and metallogenesis with regard to the deposit. The petrographic and geochemical analyses indicated that the Xintianling granite consists of three intrusive units of medium- and coarse-grained biotite granite, fine-grained biotite granite, and granite porphyry, of which the biotite granite was strongly associated with mineralization. Biotite granite rocks are highly K-calc-alkaline and weakly peraluminous, with A/CNK ratios ranging from 0.99 to 1.05. Late-granite porphyry is aluminum-supersaturated with a high evolution degree, whose geochemical characteristics suggest that it is either an I- or S-type granite. LA-ICP-MS zircon U-Pb dating revealed that medium- and coarse-grained biotite granite (162.3 ± 1.2 Ma, MSWD = 1.3), fine-grained biotite granite (161.8 ± 1.3 Ma, MSWD = 1.8), and granite porphyry (154.3 ± 1.6 Ma, MSWD = 2.4) formed in the late Jurassic. The emplacement of the Qitianling A-type granite and associated tungsten-tin polymetallic mineralization is a continuous evolution process, and they are products of the large-scale mineralization of the Nanling in the middle–late Jurassic (150–160 Ma). Under the tectonic setting of the Mesozoic lithospheric extension, asthenosphere upwelling along deep-fault, intensive mantle–crust interaction processes probably provide not only the high heat flow, but also partly mantle-derived material for large-scale W-Sn-polymetallic mineralization in this area. [ABSTRACT FROM AUTHOR]

Tungsten (W) contamination presents emerging environmental challenges, necessitating the need to establish soil screening levels (SSLs), especially for residential soils. This study assessed the health exposure risk and derived national and regional residential SSLs for W in Chinese residential soils, incorporating machine-learning prediction of in-vitro soil W bioaccessibility. We analyzed 204 residential soil samples collected across 24 provinces, recording a wide range of W concentrations (0.01-3063.2 mg/kg). Synchrotron-based X-ray fluorescence spectroscopy, chemical extractions, and random forest modeling indicated that the key determinants of soil W bioaccessibility were soil pH, cation exchange capacity, organic matter, and clay contents. Monte Carlo simulations demonstrated that soil W contamination predominantly results in noncarcinogenic health risks to residents via oral exposure, especially in mining-affected regions. A national residential SSL (NRSSL) of 35.5 mg/kg and regional residential SSLs (RRSSLs) of 34.5-49.2 mg/kg were established. Incorporating predicted bioaccessibility increased the NRSSL to 73.8 mg/kg and the RRSSLs to 69.8-112.5 mg/kg. Southern China, which is rich in W ore, exhibited lower RRSSLs, underscoring a need for enhanced safety management. Our framework and findings provide a robust scientific foundation for future soil contamination risk assessment studies, and we present customized SSLs that can guide targeted W risk control strategies., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Huihui Du reports financial support was provided by National Key Research and Development Program of China. Huihui Du reports financial support was provided by Science and Technology Innovation Program of Hunan Province. Huihui Du reports financial support was provided by National Natural Science Foundation of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Tungsten (W) is one critical metal and has been widely used in various fields due to its unique properties. China is the biggest tungsten producer and consumer in the world. However, China mainly relies on virgin tungsten resources, leading to both tungsten resource depletion and associate environmental pressures. It is therefore urgent to encourage tungsten recycling. This study aims to evaluate environmental impacts between primary and secondary tungsten carbide production in one Chinese tungsten firm by employing emergy analysis. Our results show that the total emergy input for primary and secondary tungsten carbide production is 1.16E+12 sej/g and 4.17E+11 sej/g respectively. Primary tungsten carbide production is dominated by local crustal ores, while emergy inputs for secondary tungsten carbide production is dominated by electricity and chemical consumption. Based on emergy-based sustainability indicators, environmental loading from secondary tungsten carbide production is less than that from primary tungsten carbide production. However, the value of ecosystem service has not been reflected in the prices of tungsten-related commodities. These findings provide valuable insights to those policy makers so that they can prepare appropriate tungsten resource management policies. Several policy recommendations are then proposed by considering the Chinese realities. [Display omitted] • A complete input inventory of tungsten production has been established from a life-cycle perspective. • Emergy accounting has been applied to compare the environmental impacts and resource efficiency of primary and secondary tungsten production. • Tungsten production demonstrates greater sustainability when compared to the average level of the Chinese non-ferrous metal production sector. • The real value of ecosystem services is not reflected in the prices of tungsten products. • From an economic and environmental perspective, recycled tungsten is still far from being a substitute for primary products. [ABSTRACT FROM AUTHOR]

[Display omitted] • We identified W-rich zircons from the granite in the Hukeng deposit. • These W-rich zircons record the activity of W-rich ore-forming fluids. • W/Gd ratios of zircons can be used as an indicator to estimate mineralization potential. South China is endowed with copious hydrothermal tungsten ore deposits, which are generally suggested to be associated with highly fractionated granites. However, the mechanism of tungsten enrichment and mineralization during magmatic-hydrothermal processes is not clear. Here, we clearly identified W-rich zircons (up to several thousand ppm) from the granite in the Hukeng tungsten deposit in South China. W-rich zircons are generally dark in cathodoluminescence images with irregular cracks, cavities and blurry oscillatory zones. They also show high contents of U, Nb, REEs, and high W/Gd ratios, which are not possible to be produced only by magma differentiation. Raman spectra of zircons indicate that these W-rich zircons have experienced different degrees of metamictization. Thus, these W-rich zircons should be crystallized from the late magma and subsequently altered by W-rich magmatic-hydrothermal fluids. W-rich zircons record the activity of W-rich ore-forming fluids which were exsolved from the granitic magma. We suggested that the W/Gd ratios of > 0.2 of zircons can be used as an indicator to estimate the W mineralization potential of a granite. This study provides a new pathway for using zircon to record tungsten mineralization processes and to guide tungsten ore prospecting. [ABSTRACT FROM AUTHOR]

The Yupo scheelite (Sch)-bearing deposit is hosted in the external contact zones between the Yupo granodiorite and Cambrian Huangdongkou Formation of South China. The stratiform ore bodies contain hedenbergitic pyroxene (Hd 23–69) and andradite-poor garnet (Ad 0–22) assemblages, indicating that Yupo is a typical reduced W skarn deposit. The garnet compositions are zoned in a deposit scale inwardly from the periphery of the grossular-rich skarn reaction front to more subcalcic compositions. Scheelite occurs mainly as disseminated grains in the skarn coeval with retrograde alteration (Sch I) and in quartz veins crosscutting skarns (Sch II-1, -2, and -3). Sch II-1 occurs as cores rimmed by Sch II-2, and Sch II-3 as veinlet cutting both of them. The Sch I and Sch II-3 show weak Eu anomalies different from the pronounced positive Eu anomalies of Sch II-1 and -2. All the scheelite contains low Mo contents (<0.1 wt%), together with the subordinate precipitation of molybdenite, indicating a reduced ore-forming fluid system. The Mo content and Eu anomaly jointly reveal that the reducing condition enhanced from Sch I to Sch II-1 and alleviated from Sch II-1 to Sch II-3. The four scheelite generations show gradually increased initial 87Sr/86Sr ratios from 0.7144 to 0.7242, which are higher than that of the magmatic apatite (0.7082–0.7127) and the carbonate rocks (0.7104–0.7109). The Cambrian carbonaceous shale is a high (87Sr/86Sr) i endmember that interacted with the initial ore-forming fluid; continuing interaction was deemed to enhance the reduction of the ore-forming fluid from Sch I to Sch II-1. Weakening of the intensity of fluid-rock interaction with carbonate rocks during vein-type mineralization caused the (87Sr/86Sr) i values of the scheelite to increase gradually. The input of meteoric water decreased the fluid reduction capability during the formation of Sch II-1 to Sch II-3. Fluid-rock interaction dominated the scheelite mineralization of the reduced W skarn deposit. [Display omitted] • The redox-sensitive elements Mo and Eu can provide useful discriminators for fluid. • The trace elements and Sr isotopes shed new light on the ore-forming process. • Fluid-rock interaction dominated the mineralization of scheelite. [ABSTRACT FROM AUTHOR]

The Huxingshan W deposit (0.21 Mt. WO 3 @ 0.3 %) in northeastern Hunan province is located at the western margin of the Jiangnan tungsten belt (JNB), South China. It consists of a series of magma-derived scheelite-quartz-muscovite (SQM) veins in the F1 fault (which contains over 60 % of the W resource), beneath Niutitang Formation (Fm.) carbonate rocks, and above Yijiaqiao Fm. slate (sub-economic), distal from the concealed two-mica granite, which is thought to be responsible for the tungsten mineralization. In this study, we employ LA-ICP-MS zircon and monazite U Pb, and muscovite 40Ar/39Ar dating to constrain the timing of magmatism and W mineralization at the Huxingshan deposit. Monazite and zircon dating yield coeval ages of 137.6 ± 0.5 Ma and 138.0 ± 0.5 Ma, respectively. Our muscovite 40Ar/39Ar dating yielded well plateau ages of 132.9 ± 0.6 Ma, 132.2 ± 0.6 Ma, 130.7 ± 0.5 Ma, and 129.7 ± 0.6 Ma for four representative SQM vein ore samples occurring in the Niutitang Fm. carbonate, F1 fault, and Yijiaqiao Fm. slate, indicating multiple pulses of ore-forming fluid infiltration at Huxingshan. Our age data demonstrate that the two-mica granite emplaced at ∼137.6 Ma, significantly earlier than the pulsed W mineralization at ca. 132.9–129.7 Ma. The lack of spatial and temporal association precludes any genetic link between them. Thus, we infer that the ore-forming fluids likely originated from undiscovered deep plutons and ascended through the F1 fault. Besides, our reliable ages coincide with the two periods of large-scale Mesozoic magmatism and W mineralization phases in the JNB, with the 137.6 Ma magmatism falling within the first phase (150–135 Ma), while the W mineralization (ca.132.9–129.7 Ma) falls within the second phase (130–125 Ma). Of which, the second phase, including the Huxingshan, Xianglushang, Dongping, and Jianfengpo deposits, are situated in the western JNB and show further potential in this region. [Display omitted] • The SQM (scheelite-quartz-muscovite) vein-type mineralization in Huxingshan occurs in F1 fault and beneath carbonate rocks. • The pulsed W mineralization formed at ca. 132.9–129.7 Ma cannot be sourced from the two-mica granite emplaced at ~137.6 Ma. • The Huxingshan deposit coincide with the second phase of large-scale Mesozoic W mineralization in the Jiangnan tungsten belt. [ABSTRACT FROM AUTHOR]

Hydroplumboelsmoreite (IMA21-C), (Pb,□)2(W,Fe3+)2O6(H2O), is a redefined elsmoreite-group mineral in the pyrochlore supergroup. It was found in a 'jixianite' cotype specimen provided by Mr. Liu Jianchang, who first found 'jixianite' in 1979 in the Jizhou District, Tianjin City, China. The mineral occurs as yellow to reddish brown aggregates, together with raspite and another elsmoreite-group mineral under study. Hydroplumboelsmoreite occurs in cryptocrystalline form and occasionally in octahedral microcrystalline form (under 20 μm in size). The crystals are colourless and translucent with a white streak, and the lustre is adamantine to greasy. Hydroplumboelsmoreite is isotropic, with a calculated refractive index of 2.29, a Mohs hardness of ~4½–5, and a calculated density of 7.47 g⋅cm−3. The strongest five powder X-ray diffraction lines [d in Å(I)(hkl)] are 6.070(28)(111), 3.012(100)(222), 2.603(32)(004), 1.836(35)(044) and 1.568(30)(226). The crystal structure was refined to R1 = 0.0459 using 80 unique reflections collected with MoKα radiation, and the results show that the mineral is cubic, space group Fd $\bar{3}$ m, with a = 10.3377(5) Å, V = 1104.77(16) Å3 and Z = 8. Electron microprobe analyses and crystal structure refinement were used to determine the empirical formula: (Pb1.05Sr0.05Ce3+0.07Na0.01□0.82)Σ2.00(W1.32Fe3+0.67Zr0.01)Σ2.00O6[(H2O)0.43O0.19□0.38]Σ1.00. The mineral was named hydroplumboelsmoreite based on the predominance of Pb, W, and molecular H2O in the A, B and Y sites, respectively. [ABSTRACT FROM AUTHOR]

BACKGROUND: Tungsten molybdenum ores are strategic mineral resources. China is a large producer and consumer of tungsten and molybdenum ore. Accurate and efficient analysis of tungsten and molybdenum and its associated beneficial and harmful elements is of great significance for the evaluation and comprehensive utilization of tungsten and molybdenum ore deposits. Acid dissolution and alkali fusion are the general digestion methods in tungsten molybdenum ore analysis. However, the acid solution method cannot be used to overcome the hydrolysis problem when treating samples with high content of tungsten and molybdenum, whereas the alkali fusion method such as sodium peroxide and sodium hydroxide usually introduces a large content of alkali metals, so the determination of potassium and sodium cannot be finished. OBJECTIVES: To find an efficient method for the determination of tungsten, molybdenum and 11 other elements in tungsten molybdenum ore. METHODS: Lithium metaborate melting-tartaric acid ultrasonic leaching and inductively coupled plasma-optical emission spectrometry (ICP-OES) was used for the simultaneous determination of tungsten, molybdenum, copper, lead, zinc, aluminum, iron, calcium, magnesium, titanium, manganese, potassium and sodium in tungsten-molybdenum ore. The sample was completely digested by lithium metaborate fusion. No other elements were introduced except for B and Li. Tartaric acid was used to inhibit the hydrolysis of tungsten and molybdenum. Ultrasonic leaching speeds up the dissolution of the frit. RESULTS: The experiment optimized the analysis spectrum and observation method of each element, compared the amount of flux and instrument conditions to obtain the best conditions, and used the matrix matching method to draw a standard curve to eliminate the influence of the matrix effect. The linear correlation coefficient of the standard curve of each element was greater than 0.9990, the detection limit of the method was 1.34-46.2μg/g, the relative error of measured results was 0.14%-8.7%, the relative standard deviation (RSD, n=10) of the measured results was 1.4%-7.6%. CONCLUSIONS: This method can accurately and efficiently complete the simultaneous determination of multiple elements in tungsten and molybdenum ore samples. [ABSTRACT FROM AUTHOR]

It is critical to keep a low level of tungsten impurity concentration in the core plasma of the fusion reactor. Using the OEDGE code, the influence on the tungsten concentration due to the cross-field transport in the scrape-off layer is studied. Based on the design parameters of the China Fusion Engineering Test Reactor, the background plasma with the peak target electron temperature of 15 eV is generated using the onion-skin model. The neon impurity with the assumed concentration of 0.2% inside the separatrix is included for estimating the tungsten sputtering source. In a series of simulations of tungsten transport, the diffusion coefficient D⊥ is varied from 0.1 to 10 m2 s−1, and the hypothetical inward pinch velocity VIMP is in the range of 0–5 m s−1. The tungsten concentration inside the separatrix increases with decreasing diffusion coefficient and exceeds 10−5 for the diffusion coefficient lower than about 0.2 m2 s−1. When the hypothetical inward pinch is included, the tungsten concentration increases. The relation between the relative increase in tungsten concentration and VIMP/D⊥ is fitted. [ABSTRACT FROM AUTHOR]

The Helukou deposit, with proven reserves of 33 752 t WO3, is one of the newly exploited mediumscale tungsten (W) deposits in the Guposhan ore field, Nanling Range of South China. Skarn-type and less abundant altered granite-type tungsten orebodies were identified in this deposit. The ore mineralization in this district was a product of two-stage magmatism, as shown by LA-ICP-MS U-Pb dating of zircons and Re-Os dating of molybdenite. The former yielded U-Pb ages of 184.0 ± 3.6 Ma (MSWD = 0.15) and 163.8 ± 1.5 Ma (MSWD = 0.41) for fine-grained biotite granite and muscovite granite, respectively, as well as a U-Pb age of 181.5 ± 2.1 Ma (MSWD = 0.75) for zircon grains from altered granite-type tungsten ore. The latter yielded molybdenite Re-Os ages of 183.5 ± 2.8 Ma (without MSWD owing to a limited number of samples) and 163.4 ± 2.8 Ma (MSWD = 0.71) for altered granite-type and skarn-type tungsten deposits, respectively. Thus, two separate tungsten mineralization events occurred during the Early Jurassic and Middle Jurassic. Trace-element compositions suggest that scheelite I was controlled by the coupled substitution reactions of 2Ca2+ = Na+ + REE3+ and Ca2+ + W6+ = Nb5+ + REE3+, whereas scheelite II was controlled by the coupled reactions of 2Ca2+ = Na+ + REE3+ and 3Ca2+ = Ca + 2REE3+ (where  is a site vacancy). High Mo and low Ce contents suggest that both scheelite I and scheelite II were precipitated from oxidizing magmatic-hydrothermal fluids. Based on the mineral assemblage of the altered granite-type ores and geochemical characteristics of scheelite I [i.e., negative Eu anomalies (0.02-0.05; mean = 0.03 and STD = 0.01), and high 87Sr/86Sr ratios (0.70939-0.71932; mean = 0.71345 and STD = 0.00245)], we infer that fluid-rock interaction played an important role in modifying Early Jurassic ore-forming fluids. Scheelite II exhibits a geochemical composition [i.e., 87Sr/86Sr ratios (0.70277-0.71471; mean = 0.70940 and STD = 0.00190), Eu anomalies (0.14-0.55; mean = 0.26 and STD = 0.09), and Y/Ho ratios (16.1-33.7; mean = 27.9 and STD = 2.91)] similar to that of the Middle Jurassic Guposhan granites, suggesting inheritance of these features from granite-related magmatic-hydrothermal fluids. These results provide new insights into the two-stage magmatic and metallogenic history of the Nanling Range during the Jurassic Period. [ABSTRACT FROM AUTHOR]

The technology of pulse-plasma modification of the working surface of the die of 4Kh5MF1S tool steel (analogues are X40CrMoV5-1 in the EU and 4Cr5MoSiV1 in China) was considered. The mentioned tool is used for stamping billets of titanium VT6 alloy (wt.%: Al -- 3.0--6.8; V -- 3.5--5.0; Ti -- base), which is performed at temperatures of up to 700 °C. The die surface is heated, which leads to its oxidation and diffusion redistribution of alloying elements. Pulse-plasma stamping leads to the formation of elastic-plastic deformations of the surface layer in a tool steel, which in combination with pulsed thermal and electromagnetic effects provides a refinement of the alloy structure and intensifies the diffusion mechanisms of alloying elements. The studies showed that the modified layer (over 80 µm thickness) in 4Kh5MF1S steel, formed in the process of pulse-plasma treatment, contains up to 2.5 % carbon, up to 12 % oxygen and up to 3 % tungsten. In the mentioned layer the presence of nanocrystalline structures with a size of less than 100 nm was revealed. The hardness of the modified layer is more than 700 HV0.025. The surface roughness after pulse-plasma treatment did not change. Experience of industrial use of this technology showed that modification of a surface of the die from 4Kh5MF1S steel provided its high serviceability at a deep drawing of products from the heated (to 700 °C) sheet of VT-6 titanium of 3 mm thickness. [ABSTRACT FROM AUTHOR]

[Display omitted] • The concentration and spatial distribution of tungsten in China outlined. • Catchment sediments with high tungsten concentrations is scattered south China. • Concentration centers of tungsten anomalies are correlated with parent rock, tungsten mineralization. • Nine anomalously high content regions were identified for tungsten prospecting targets in China. Tungsten (W), known as the "teeth of industry", is a critical mineral resource for emerging industries worldwide. Given the crucial role of tungsten in various industrial and military applications, its potential as a mineral resource for China must be assessed. Determining the concentration and distribution of tungsten in catchment sediment environments is key to such assessments. Therefore, based on the China Geochemical Baselines (CGB) project, we obtained information on the continental-scale concentrations, variations, and distributions of tungsten throughout mainland China. The tungsten concentrations in the top and deep sediment samples varied from 0.20 to 294 ppm, with a median value of 1.56 ppm, and 0.25 to 216 ppm, with a median value of 1.51 ppm, respectively. The tungsten concentrations varied widely across regions, with the distribution at the catchment scale predominantly controlled by the parent rock, especially granites and alkaline rocks, and the distribution at the continental scale primarily controlled by mineralization. Generally, the spatial distribution of tungsten in the top and deep catchment sediments was relatively consistent, with higher concentrations in South China and lower concentrations in Northwest China. Furthermore, nine large to super-large tungsten prospecting belts were delineated. Numerous well-known tungsten deposits have been located, especially in the South China anomalous belt (with an area of approximately 1.03 million km2), which exhibits an anomalous distribution trend of prospecting tungsten deposits from the south to north, and the east to west. Moreover, the Xizang (Tibet)-Sanjiang anomaly belt (approximately 585,000 km2) represents an important future exploration target for tungsten deposits. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrothermal alteration changed the CL color of scheelite at Huangjindong. • Trace elements correlation reveals the approach of REE incorporating into scheelite. • Sr isotopes indicate a metamorphic fluid source for scheelite at Huangjindong. • Pressure reduction dominates the scheelite precipitation in orogenic gold deposits. Scheelite and wolframite are two primary tungsten minerals in nature. The occurrence of tungsten minerals varies in different types of deposits, with scheelite rather than wolframite typically forming in orogenic gold deposits. However, the explanation for this phenomenon remains unclear. Huangjindong deposit, located in the center of the Jiangnan Orogenic Belt in southern China, is a typical orogenic gold deposit with scheelite mineralization. Texture, in-situ trace elements and Sr isotope compositions of scheelite from this deposit were investigated to explore the formation process of scheelite and the source of tungsten of similar orogenic gold deposits. Three hydrothermal stages have been identified at this deposit: milky scheelite + quartz (pre-gold Stage I); gold + sericite + sulfide + quartz (syn -gold Stage II); and dolomite + quartz (post-gold Stage III). Scheelite primarily occurs during the initial pre-gold stage. Local color differences in CL image have developed along rims and in domains adjacent to fractures of scheelite due to slight late-stage hydrothermal alteration of scheelite along their fractures. The intense development of sericite and chlorite alteration in the host rocks indicates that the water–rock reaction consumed a large amount of H+. Within the scheelite-quartz veins, the presence of brecciated slate enclaves and localized quartz geodes, indicating that the fluid experienced significant pressure drop. This indicates that the water–rock reaction and the decrease in pressure resulted in the precipitation of scheelite. The dominance of tungsten mineral precipitation due to pressure reduction serves as the main factor driving the development of scheelite over wolframite within the deposit, which also elucidates the reason that tungsten mineralization associated with orogenic gold deposits predominantly features scheelite. The characteristics of scheelite without oscillatory zoning, high Sr (1180–8600 ppm) and low Mo (bdl-0.18 ppm) concentrations, and flat REE pattern are similar to those of scheelite in orogenic gold deposits worldwide. The high 87Sr/86Sr ratio (0.7539–0.7663) indicates that the tungsten-bearing ore-forming fluids derived from deep-seated metamorphic fluids. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three generations of tungsten minerals have been identified in the Hongling tungsten deposit. • Fluid-induced dissolution–reprecipitation processes are responsible for the formation of tungsten minerals. • Intensive hydrothermal processes are critical to the mineralization of tungsten in magmatic-hydrothermal systems. Tungsten is a critical metal that is predominantly found in magmatic-hydrothermal W-Sn deposits. However, the behavior and controlling factors of tungsten in highly evolved granitic systems are not yet well-known. In this study, we examined the integrated mineral textures and geochemistry of wolframite and scheelite from the Hongling tungsten deposit in the word-class Nanling W-Sn metallogenic belt, South China. Our results reveal that wolframite and scheelite from the muscovite granite of the highly evolved Reshui granite pluton can be classified into three generations formed through a process of coupled dissolution-reprecipitation. Wolframite with altered relict textures was formed during the early magmatic stage, while the two generations of scheelite (Sch-I and Sch-II) were formed during the magmatic-hydrothermal transitional stage. The formation of Sch-I, which exhibits a notable positive Eu anomaly, required the participation of external Ca-rich reduced fluids within the magmatic exsolved fluids from the highly evolved peraluminous pluton. The porous Sch-II occurs as marginal overgrowth or fracture-filling textures and exhibits a similar negative Eu anomaly as the dissolved wolframite. These three generations of tungsten minerals exhibit distinguishable REE contents and distribution patterns, with increasing LREE and decreasing HREE trends. The fluctuation of oxygen fugacity and the compositional evolution of tungsten minerals from wolframite through Sch-I to Sch-II indicate the involvement of external Ca-rich reduced fluids within the magmatic exsolved fluids from the highly evolved peraluminous pluton. The coupled dissolution of wolframite and the reprecipitation of scheelite were likely induced by intensive fluid-rock interactions, which are critical for the remobilization and enrichment of tungsten in magmatic-hydrothermal deposits. We inferred that such fluid-induced dissolution-reprecipitation of tungsten minerals provides new insights into the formation of the world-class Nanling W-Sn metallogenic belt in South China. [ABSTRACT FROM AUTHOR]

An empirical equation has been proposed to describe geochemical backgrounds of trace elements during rock weathering on weathering and lithological indices. However, with respect to lithium, the equation was derived on only 9 regolith profiles in China and was not applicable to carbonate-bearing materials with WIG (weathering index of granite) larger than 120. To derive a robust and widely used equation on geochemical backgrounds of lithium, 851 elemental abundance data including 379, 280, and 192 records of rocks, soils, and stream sediments, respectively, were used to fit the new equation. lg c = −0.02630 xy 2 z + 0.03000 xyz 2 + 0.03540 xy + 0.6425 y + 3.288 for WIG<20 （1） lg c = 0.00001579 x 2 yz + 0.001141 y 2 xz - 0.9445 y + 0.3650 z for 20≤WIG<120 （2） lg c = 0.1849 xy 2 z + 0.03382 xyz 2 + 0.6839 xyz - 09414 x - 1.471 y + 1.070 z for WIG≥120 （3） where c is the calculated geochemical background of Li in μg/g. WIG is the weathering index of granite. The x in Eq. (1) and Eq. (2) is WIG and is lg(WIG) in Eq. (3). The y is lg(Al 2 O 3 /Ti) where Al 2 O 3 and Ti represent their contents with units of wt% and μg/g respectively. The z is lg(K 2 O/SiO 2) where K 2 O and SiO 2 represent their contents in wt%. The fitting data of Li, WIG, Al 2 O 3 /Ti, and K 2 O/SiO 2 are 3.5–70 μg/g, 6.9–9400, 0.0003–0.0356, and 0.0006–0.1410, respectively. By comparison with the previous equation in a linear fitting, the newly presented equation in a nonlinear fitting is applicable to geological materials without WIG limitations. However, to the materials with WIG ranging from 0 to 120, the fitted results between the previous and the newly presented equations are generally similar. In summary, the new equation works well to describe lithium geochemical backgrounds of geological materials and could play an important role in environmental and exploration geochemistry. In mineral exploration, the method of seven levels' classification of geochemical anomaly can be improved on this newly presented equation and has been validated in the Tieshanlong tungsten deposit area in Southeastern China. • A new equation on 851 elemental abundances was proposed using the partial derivative quadratic function theory to describe Li geochemical backgrounds. • The new equation is applicable to samples in the rock-soil-sediment systems. • The new equation is potential in environmental and exploration geochemistry. [ABSTRACT FROM AUTHOR]

The tin (Sn)-tungsten (W) polymetallic ore concentrated district in SE Yunnan is distributed at the junction region of the Yangtze Block, the Cathaysian Block and the Indosinian Block, where there are several giant deposits of tin, tungsten, copper, silver, lead, zinc and indium closely associated with a large scale Late Cretaceous magmatism. Bi-dimensional empirical mode decomposition (BEMD) is used to extract aeromagnetic anomalous components at the survey scale of 1: 200 000 from the original aeromagnetic data of SE Yunnan. Four intrinsic mode functions (IMFs) and a residues component are obtained, which may reflect the geological structures and geological bodies at different spatial scales from high frequency to low frequency. The results are shown as follows: (1) Two different types of Precambrian basement in the study area were recognized: one is the Yangtze Block basement characterized by a strong positive magnetic anomaly, the other is the Cathaysian Block basement with a weak negative magnetic anomaly. The former consists of high grade metamorphic rocks including metamorphosed basic igneous rocks, while the latter consists of low grade metamorphosed sedimentary rocks. (2) The aeromagnetic anomalies associated with Sn-W polymetallic mineralization and related to granites in the study area illustrate a pattern of a skarnized alteration-mineralization zone with a positive ring magnetic anomaly enclosing a granitic intrusion with negative magnetic anomaly; (3) The ring positive magnetic anomaly zones enclosing the negative magnetic anomaly are defined as the Sn-W polymetallic ore-searching targets in the study area. [ABSTRACT FROM AUTHOR]

The paper presents the assessment of equivalence of the spectral radiance scales in the wavelength range from 250 to 2500 nm, reproduced at the national metrology institutes of Korea (KRISS), China (NIM), and Russia (VNIIOFI), carried out in the framework of international comparisons. The common set of three tungsten strip lamps was used as an artefact. Based on a series of blind measurements of the lamps spectral radiance performed at each laboratory alternately, the reference value of the comparison was determined at each wavelength as a weighted mean of the measured data of three laboratories. The degree of equivalence of each laboratory was then calculated as the deviation of the measurement data of that participant from the reference value. A data analysis method was proposed for calculating the degree of equivalences and their uncertainties. The method is based on processing spectral radiance ratios, rather than differences, which allows eliminating the influence of a result of one particular participant to results of other laboratories. The comparison results confirm the equivalence of spectral radiance scales of all the laboratories within their expanded uncertainties (k = 2) except a few wavelength points. [ABSTRACT FROM AUTHOR]

Tungsten deposits are usually associated with granitic intrusions that record a long and complex evolution of the magmatic-hydrothermal system. However, the genetic link between magmatic-hydrothermal evolution and tungsten mineralization remains unclear. The Xihuashan tungsten deposit in South China, an important vein-type wolframite deposit, is closely associated with greisen and multiphase intrusive activity that produced biotite granite, two-mica granite, and muscovite granite. From the biotite granite to the two-mica granite to the muscovite granite, micas vary from siderophyllite to lithian siderophyllite, with decreasing K/Rb and Nb/Ta ratios and increasing Rb and Cs contents. The zoned micas in the muscovite granite and greisen display fluorine-depleted rims, reflecting subsolidus replacement by external aqueous fluids. The presence of siderite indicates a Fe-, Mn-, and CO2-rich fluid under reducing conditions. The micas in the greisen have higher-F contents and lower Fe3+/Fe2+ ratios than those in the muscovite granite, suggesting that the fluids contributing to greisen formation had a relatively high-fluorine content and were reduced. The increase of CO2 in the fluid enhanced its ability to unlock W from melts/rocks into fluids. The reducing environment also facilitated the tungsten mineralization. During greisenization, the pH value of the fluid increased, which destabilized the polymeric tungstates to form WO42–. The mixture of W-rich solution and Fe-, Mn-rich external fluid eventually precipitated as vein-type wolframite in favorable locations. An empirical equation (Li2O = 0.0748 × F2 + 0.0893 × F) was introduced for estimating the Li2O contents of hydrothermal micas using the F contents determined by EPMA. [ABSTRACT FROM AUTHOR]

The Maoping tungsten deposit is located in the Nanling W–Sn metallogenic belt in South China. Greisen and quartz vein types of mineralization developed in this deposit. Protolithionite occurs in the granite. Zinnwaldite is occurs mainly in greisen and wolframite–quartz veins whereas phengite is found in the underground quartz veinlets. In granite and greisen, protolithionite, and zinnwaldite are partly replaced by Li-phengite. LA-ICP-MS trace element analyses of micas and wolframite are employed to characterize the ore-forming source and evolution of ore-forming fluids. Micas show compositional variation trend in vertical directions with a decrease of W, Sn, Nb, and Ta and an increase of MgO, V, Ni, and Co. Wolframite in greisen has higher Mo, Sn, Nb, Ta, and REEs than those in quartz veins. All wolframites show similar REE patterns with enrichment of HREE. Wolframites in greisen and quartz veins have negative Eu anomalies, while wolframites in quartz veinlet display positive Eu anomalies. Compositions of mica and wolframite from different mining levels of the Maoping deposit suggest that the ore-forming fluids are dominated by magmatic hydrothermal fluids in the deep with a slight addition of meteoric water in the shallow. Brittle fracture-induced depressurization and fluid mixing controlled the evolution of ore-forming fluids and possibly lead to the wolframite deposition. [ABSTRACT FROM AUTHOR]

The Zhuxi tungsten deposit in Jiangxi Province, South China, contains a total W reserve of about 2.86 Mt at an average grade of 0.54 wt% WO3, representing the largest W deposit in the world. Numerous studies on the metallogeny of the deposit have included its timing, the ore‐controlling structures and sedimentary host rocks and their implications for mineral exploration. However, the deep nappe structural style of Taqian–Fuchun metallogenic belt that hosts the W deposit, and the spatial shape and scale of deeply concealed intrusions and their sedimentary host rocks are still poorly defined, which seriously restricts the discovery of new deposits at depth and in surrounding areas of the W deposit. Modern 3D geological modeling is an important tool for the exploration of concealed orebodies, especially in brownfield environments. There are obvious density contrast and weak magnetic contrast in the ore‐controlling strata and granite at the periphery of the deposit, which lays a physical foundation for solving the 3D spatial problems of the ore‐controlling geological body in the deep part of the study area through gravity and magnetic modeling. Gravity data (1:50000) and aeromagnetic data (1:50000) from the latest geophysical surveys of 2016–2018 have been used, firstly, to carry out a potential field separation to obtain residual anomalies for gravity and magnetic interactive inversion. Then, on the basis of the analysis of the relationship between physical properties and lithology, under the constraints of surface geology and borehole data, human–computer interactive gravity and magnetic inversion for 18 cross‐sections were completed. Finally, the 3D geological model of the Zhuxi tungsten deposit and its periphery have been established through these 18 sections, and the spatial shape of the intrusions and strata with a depth of 5 km underground were obtained, initially realizing "transparency" for ore‐controlling bodies. According the analysis of the geophysical, geochemical, and geological characteristics of the Zhuxi tungsten deposit, we discern three principles for prospecting and prediction in the research area, and propose five new exploration targets in its periphery. [ABSTRACT FROM AUTHOR]

Rare metals including Lithium (Li), Beryllium (Be), Rubidium (Rb), Cesium (Cs), Zirconium (Zr), Hafnium (Hf), Niobium (Nb), Tantalum (Ta), Tungsten (W) and Tin (Sn) are important critical mineral resources. In China, rare metal mineral deposits are spatially distributed mainly in the Altay and Southern Great Xingán Range regions in the Central Asian orogenic belt; in the Middle Qilian, South Qinling and East Qinling mountains regions in the Qilian–Qinling–Dabie orogenic belt; in the Western Sichuan and Bailongshan–Dahongliutan regions in the Kunlun–Songpan–Garze orogenic belt, and in the Northeastern Jiangxi, Northwestern Jiangxi, and Southern Hunan regions in South China. Major ore‐forming epochs include Indosinian (mostly 200–240 Ma, in particular in western China) and the Yanshanian (mostly 120–160 Ma, in particular in South China). In addition, Bayan Obo, Inner Mongolia, northeastern China, with a complex formation history, hosts the largest REE and Nb deposits in China. There are six major rare metal mineral deposit types in China: Highly fractionated granite; Pegmatite; Alkaline granite; Carbonatite and alkaline rock; Volcanic; and Hydrothermal types. Two further types, namely the Leptynite type and Breccia pipe type, have recently been discovered in China, and are represented by the Yushishan Nb–Ta– (Zr–Hf–REE) and the Weilasituo Li–Rb–Sn–W–Zn–Pb deposits. Several most important controlling factors for rare metal mineral deposits are discussed, including geochemical behaviors and sources of the rare metals, highly evolved magmatic fractionation, and structural controls such as the metamorphic core complex setting, with a revised conceptual model for the latter. [ABSTRACT FROM AUTHOR]

Unlike classic skarn-type scheelite deposits directly acquiring sufficient Ca2+ from surrounding limestones, all of the scheelite orebodies of the Shangfang tungsten (W) deposit occur mainly in amphibolite, and this provides a new perspective on the mineralization mechanism of W deposits. The ability of hydrothermal scheelite (CaWO4) to bind REE3+ in their Ca2+ crystal lattices makes it a useful mineral for tracing fluid-rock interactions in hydrothermal mineralization systems. In this study, the REE compositions of scheelite and some silicate minerals were measured systematically in-situ by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to assess the extent of fluid-rock interactions for the Late Mesozoic quartz-vein-type Shangfang W deposits. According to the variations in CaO and REE among scheelite and silicate minerals, the amphibole and actinolite in amphibolite may be able to release large amounts of Ca2+ and REE3+ into the ore-forming fluids during chlorite alteration, which is critical for scheelite precipitation. Furthermore, an improved batch crystallization model was adopted for simulating the process of scheelite precipitation and fluid evolution. The results of both the in-situ measurements and model calculations demonstrate that the precipitation of early-stage scheelite with medium rare-earth elements (MREE)-rich and [Eu/Eu*]N<1. The early-stage scheelite would consume more MREE than LREE and HREE of fluid, which will gradually produce residual fluids with strong MREE-depletion and [Eu/Eu*]N>1. Even though the partition coefficient of REE is constant, the later-stage scheelite will also inherit a certain degree of MREE-depletion and [Eu/Eu*]N future from the residual fluids. As a common mineral, sheelite forms in various types of hydrothermal ore deposits (e.g., tungsten and gold deposits). Hence, the improved batch crystallization model is also possible for obtaining detailed information regarding fluid evolution for other types of hydrothermal deposits. The results from model calculations also illustrate that the Eu anomalies of scheelite are not an effective index correlated to oxygen fugacity of fluids but rather are dominantly controlled by the continuous precipitation of scheelite. [ABSTRACT FROM AUTHOR]

The short-lived 182Hf-182W system has been used to constrain the early Earth's accretion and differentiation. This paper reports high precision W isotopic compositions and trace element concentrations for Archean (4.0–3.0 Ga) intermediate to felsic rocks from the Slave, North China, and Kaapvaal cratons to discuss early Earth differentiation and mantle mixing processes. The 4.0–3.8 Ga diorite and trondhjemite samples from the Acasta Gneiss Complex (AGC) in the Slave Craton and Anshan Complex in the North China Craton have positive μ182W values ranging from 8.3 ± 3.6 to 14.5 ± 4.0, whereas the 3.36–2.95 Ga TTG rocks from the North China Craton have a uniform modern mantle-like μ182W value of 0.7 ± 3.9 (2 SD, n = 11); with one exception, the 3.32 Ga old sample F28-2, which has a positive μ182W anomaly (7.3 ± 3.9 and 13.0 ± 3.2 for two individual analyses). The Earth's oldest potassic granites, occurring as conglomerates in the Moodies Group, an intrusive trondhjemite, and an amphibolite with ages of ~3.55 Ga in the Kaapvaal Craton exhibit W isotopic compositions indistinguishable from what is proposed for the modern mantle. The positive 182W anomalies in the 4.0–3.8 Ga rocks could possibly be the result of either early mantle differentiation that occurred within the lifetime of 182Hf or a partial lack of late accreted material. The signature of 182W excess in the 3.32 Ga sample (F28-2) is inherited from earlier crust, presumably similar to the 3.8 Ga TTGs, either by melting or crustal contamination. The transition in μ182W values from positive to near-zero would indicates that a significant event occurred at ∼3.6 Ga which caused efficient mixing of early differentiated mantle and late accreted material, possibly indicating the transition of tectonic regimes from plume to plate tectonics on the Earth. [ABSTRACT FROM AUTHOR]

The Yangbishan iron–tungsten deposit, located in the central part of the Jiamusi Massif, Heilongjiang Province, NE China, is the oldest tungsten deposit in NE China to date. Both ore‐forming conditions and mineralisation characteristics indicate that tungsten mineralisation belongs to the skarn type. Petrography, microthermometric measurements and laser Raman spectroscopy of fluid inclusions in quartz grains associated with scheelite indicate that the ore‐forming fluid of the tungsten mineralisation in Yangbishan deposit belonged to the moderate‐temperature NaCl–H2O–CH4±N2 system. Fluid inclusion analyses indicate that ore‐forming fluid experienced decreasing temperatures and fluid degassing, inducing scheelite precipitation. Analysis of C, H and O isotopes of fluid inclusions within scheelite grains show δ13C values varying from −20.7 to −24.9‰, δD from −109.9 to −119.9‰, δ18O from 6.8 to 10.0‰ and δ18OH2O from 8.7 to 11.9‰. These data, together with C, H and O isotope compositions of the quartz associated with scheelite in tungsten ores, imply that ore‐forming fluid was derived dominantly from magma but influenced by organic material (reducing carbon) derived from wall rocks. Sm/Nd ratios of scheelite vary from 0.15 to 0.21, εNd (t = 520 Ma) values from −5.64 to −17.95 (average of −10.21) and TDM2 values from 702 and 2693 Ma (average of 2070 Ma), indicating the ores were sourced from ancient crustal rocks. The compositions of C–H–O–S–Pb and Nd isotopes support the fact that interaction between crust‐derived magma and strata rich in organics played an important role in the tungsten mineralisation of the Yangbishan deposit. [ABSTRACT FROM AUTHOR]

Salicylhydroxamic acid is an excellent collector of oxidizing ore, and it has an efficient collection performance for tungsten molybdenum ore. However, the utilization ratio of salicylhydroxamic acid is relatively low in the flotation process, and a large amount of flotation wastewater discharged might cause damage to the water environment. This study mainly compared the effects of natural sunlight degradation, ozonation, and Fenton oxidation processes on the treatment of salicylchydroxamic acid wastewater from W–Mo mineral processing. The results showed after 30 hours degradation by natural sunlight, the CODcr removal rate of wastewater was only 25.99%. When the initial pH was 8, the dosage of O3 was 1.3 mg/L and the reaction time was 60 minutes; O3 oxidation could remove 40.37% CODcr from wastewater, and the BOD5/CODcr value increased to higher than 0.3 after 15 min reaction. Under the Fenton oxidation conditions such as initial pH 3, H2O2 dosage 0.96 g/L, and the molar ratio of H2O2 to Fe2+ 2 : 1, 90.43% CODcr could be removed from flotation wastewater after 90 min reaction, and the BOD5/CODcr value was obviously improved. Fenton oxidation was a high efficient processing technology for salicylhydroxamic acid wastewater, and the effluent could meet the discharge and reuse emission standard requirements in China. [ABSTRACT FROM AUTHOR]

The North Wuyi area is an important metallogenic belt in South China and hosts many Pb–Zn–Ag deposits within the Jurassic–Cretaceous volcanic basins. These deposits are mostly genetically associated with Late Jurassic magmatism. The Cretaceous granitic rocks in the Lizikeng basin, at the eastern part of the North Wuyi area, were investigated for their mineralogical and geochemical characteristics in this study. Three types of granitic rocks, quartz monzonite, granite porphyry, and monzogranite, occur, and zircon U–Pb dating reveals that they all formed during the short period of 133–129 Ma, corresponding to the early Cretaceous volcanic-intrusive activities in South China. The whole-rock geochemistry indicates that all three granitic rocks have I-type affinity. The quartz monzonite and granite porphyry have consistently low whole-rock εNd(t) values of − 10.4 to − 9.6 and zircon εHf(t) values of − 14.2 to − 8.2, and they were likely derived from Proterozoic crustal sources without any significant contribution of mantle-derived material. The monzogranite, which shows also negative but slightly higher εNd(t) and εHf(t) values of − 7.6 to − 7.1 and − 9.3 to − 7.0, respectively, might also be derived from a major Proterozoic crustal source but with some input of mantle magma. The geochemical data show that the monzogranite belongs to tungsten-bearing granite with highly evolved characteristics, and with high Nb and W contents similar to the typical rare-metal and W-bearing granites in South China. A large number of typical hydrothermal rare-metal minerals are identified in the monzogranite, such as W-bearing rutile, niobian rutile, and columbite-group minerals as well as ferberite. The discovery of the early Cretaceous granitic rocks with tungsten mineralization potential indicates that the North Wuyi area is prospective for rare-metal mineralization, which opens a new window for rare-metal prospecting in the volcanic basins, as this type of ore deposit was previously thought to occur in granites from mountain range areas in South China, such as the Nanling Range. [ABSTRACT FROM AUTHOR]

BACKGROUND: Global harmonious high-quality geochemical data and accompanying maps are reference baselines for quantifing future human-induced or natural environmental changes. OBJECTIVES: In order to ensure the accuracy of geochemical reference values and analytical data, advisions were made for laboratory analysis. METHODS: The analytical data of Cd, Hg and W from China, USA, Europe and Australia were compared and two analysis data of the sam laboratory in China at an interval of 15 years were also compared. RESULTS: The analysis data of cadmium in different laboratories and the same laboratory at 15-year intervals are consistent with a correlation coefficient of 0.96. But mercury is poorly consistent with a correlation coefficient of 0.74, and tungsten is not comparable with a correlation coefficient of 0.56). The analysis results of cadmium are highly consistent because the analysis method is the same and the detection limit is close. The consistency of mercury is poor, especially the low-content mercury is significantly different because the analysis method and detection limit are different. Tungsten is not comparable in different laboratories because of different laboratory analytical methods.The prerequist for recognition of environmental changes (RCenv> REsmpl+RDlab) is that the change value must be larger than the value of field sampling error (REsmpl) and laboratory analysis error (RDlab). Therefore, sampling errors and laboratory analysis errors must be minimized. CONCLUSIONS: Six general guidelines are proposed. 1) The original sample was separated through a 10-mesh sieve and processed to a particle size of less than 200 mesh using pollution-free method. 2) A total of 71 elements plus other parameters should be determined by well-established mulitiple analyticalmethods, e.g., fussed glass bead-XRF for major elements and 4-acids ICP-MS and ICP-OES for minor elements in combination with other methods. 3) The method detection limits must be lower than crustal abundance of the chemical elements and reportable data percentage must be more than 90%. 4) The geochemical reference materials used for quality control should contain the reported certified CRM values for all elements. 5) Analytical relative errors for the triplicate samples should be less than 40% (RD ≤ 40%) if concentration of the element is less than 3 times detection limits, and less than 20% (RD ≤ 20%) for the elements with concentration more than 3 times detection limits as well as major elements, Fe-group elements and toxic metals. 6) The total contents of major elements SiO2, Al2O3, Fe2O3, FeO, MnO, MgO, CaO, Na2O, K2O, TiO2, P2O5, H2O+, CO2, SO2 and organic maters or those of SiO2, Al2O3, Fe2O3, FeO, MnO, MgO, CaO, Na2O, K2O, TiO2, P2O5,and LOI should be at 99.3%-100.7%. [ABSTRACT FROM AUTHOR]