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This study investigates an environment-centered, state-driven corrosion prognosis framework to predict the long-term atmospheric corrosion loss of metal materials, and this paper takes carbon steel as an example to show the establishment process of the framework. Unlike traditional power-linear prediction models that seldomly consider environmental impacts, the proposed model quantitatively establishes the correlations between corrosion loss and dynamic atmospheric environmental factors. A comprehensive power-linear function model integrating multiple atmospheric environmental factors is constructed, following the corrosion kinetics robustness. Under the proposed framework, the steady-state start time is evaluated, followed by the long-term corrosion loss prediction under different corrosivity categories and test sites. The applicability is justified via a case study of long-term field exposure tests of metal materials in China, as well as the experimental results of the ISO CORRAG program. By comparing with the traditional power model and ISO model, the experimental results demonstrate the capability and effectiveness of the proposed prognosis methodology in acquiring accurate corrosion state information and corrosion loss prediction results with less input corrosion information. [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 application of whole-rock compositions to trace magma evolution or crystal-melt equilibrium may be called into question when foreign crystals are incorporated into host magmas. To address this challenge, establishing the origins (orthocrysts, antecrysts, xenocrysts, etc.) of minerals with variable textures in magmatic plumbing systems is necessary. In this paper, we describe complex oscillatory zoning patterns of clinopyroxenes (Cpx) from the Miocene Majuangou (MJG) alkali basalts from West Qinling, China. Our detailed petrographic, mineralogical, and geochemical analyses unravel the origins of various Cpx crystals with distinct textural patterns, thereby providing information about magma storage, recharging and/or mixing, and transportation, as well as the reactions between crystals and melts/fluids. Based on textural patterns, Cpx may be divided into four types: normal (Type-1 Cpx), simple oscillatory (Type-2 Cpx), complex oscillatory (Type-3 Cpx), and grains that lack zoning (Type-4 Cpx, suggested to be orthocrysts). Through the textural characterization of Cpx, the comparison between different types of Cpx, and the relationships between Cpx major compositions from different lithologies, we concluded that Type-1–3 Cpx cores are antecrysts or xenocrysts with diverse origins: primitive magma (Type-1 Cpx cores), magma mush (Type-2 Cpx cores), and crustal granulite (Type-3 Cpx cores). The zoning patterns and the compositions of these Cpx crystals indicate at least three batches of magmatic activity, i.e., the Batch-1 low-Mg# magma (Mg#: 47.4–53.3), the Batch-2 primitive magma (Mg#: 57.2–64.5), and the Batch-3 low-Mg# host alkali magma (Mg#: 47.2–54.6). Cpx-melt thermobarometry demonstrates that at least two crustal magma reservoirs existed in the magma plumbing system at depths of 30.1 and 40.9 km. The antecrystic/xenocrystic Cpx cores were captured by, continued to grow in, and subsequently reacted with ascending K-rich melt/fluid. The spongy textures in Cpx cores/mantles are attributed to this reaction, which may be expressed as: Melt 1 (primitive or evolved) + K-rich melts/fluids + Cpx (CaMgSi2O6) = K-feldspar (KAlSi3O8) + ilmenite (FeTiO3) + Melt 2 (derivative). The products of this reaction (K-feldspar and ilmenite) filled the sieves in the spongy zones of Type-1–3 Cpx. This detailed investigation of compositional and textural features of Cpx antecrysts/xenocrysts suggests that the interactions between various interconnected magma reservoirs are widespread beneath the magmatic plumbing system. Our study emphasizes the importance of the incorporation of foreign crystals and the Cpx-melt/fluid reaction in magmatic plumbing system, which can significantly modify the whole-rock compositions and lead to the formation of spongy textures without the need for fractures and cracks in minerals. [ABSTRACT FROM AUTHOR]

Systemic functional translation studies (SFTS) has been a research area sustained by scholars from both Systemic Functional Linguistics (SFL) and translation studies over the past decades. In China, there have been an increasing number of studies in SFTS after the 2000s, with Professor Guowen Huang being one of the pioneering and influential scholars contributing to this emerging research area. This paper is a transcript of an interview conducted with Guowen Huang and it serves to provide a general introduction to his research. In the interview, he discusses his motivation for exploring SFTS, the advantages of applying SFL to translation studies, and the Ph.D. students he has supervised over the past decades. He also introduces his own work on the translations of ancient Chinese poems, the translations of the Analects (Lunyu 论语) of Confucius, and his investigation of applying ecolinguistics to translation studies. Finally, he suggests some future studies needed in this area. [ABSTRACT FROM AUTHOR]

This article explores some features of digital payments in China to raise analytical questions for a pragmatist anthropology of money. It shows that digital payments in China are concentrated in two companies, that are part of a small oligopoly of companies that organize digital connections among around 850 million people in the territory. This raises questions concerning the role of digital payments for social interdependence and the constitution of social hierarchies. The second section analyzes the institutional setting and the legitimizing narratives with which this happens. It shows a complex interdependence between the state and non-state-owned big technological companies, which produce legitimizing narratives that can be shared, divergent or even contradictory. This raises questions concerning the role of digital payments in the project of constituting a national society. In the conclusion, the paper recalls that, although these developments in the Chinese territory cannot be replicated elsewhere, they pose important questions for the analysis of digital money's present and potential futures worldwide. [ABSTRACT FROM AUTHOR]

In the current social and economic world context, Chinese trade relations represent a challenge for all partners. The article provides an overview of bilateral trade, especially export, between the European Union (EU) and China in the apparel and accessories industry, most performance parts of the bilateral relations from the textile industry. The research is highlighting the major trends of export relations for this industry during 2001–2019. The author presents the evolution of articles of apparel and accessories exports in the EU and China, emphasizing the major tendencies for each of them. Further are developed benchmarks of Romanian contribution to the relationship between EU and China. The methods used present a multi-method approach, utilizing primary and secondary research through exploratory data from the official website regarding the apparel industry, as EU Statistics, International Trade Centre, and others. The main result of the paper shows that at the European level, one of the most important objectives for the apparel industry is to assure EU–China trade feasible barrier export instruments to develop efficiently the bilateral exports. [ABSTRACT FROM AUTHOR]

While post-disaster rebuilding is an urgent task for affected areas, an approach without consideration for climate protection will probably lead to another disaster of carbon lock-in. Therefore, policymaking and implementation are critically important. This paper takes the Guangyuan prefecture as a case study, where the local government took the lead in low-carbon initiative and made a great contribution to low-carbon development. Based on long-term field investigations and semi-structured interviews, using the theory of multi-level governance, it discusses policy formation and implementation in the Guangyuan prefecture, and how the governance system promoted an environment-and-climate-friendly rebuilding. The results demonstrate the urgency of carbon decoupling in post-disaster-rebuilding and the significance of an effective governance system. This provides insight to the contemporary world that post-disaster rebuilding is not only a revitalization of the affected areas, but a comprehensive undertaking to avoid other possible disasters and ensure a sustainable future. [ABSTRACT FROM AUTHOR]

This review summarizes the history, function, application, and achievement of the RheumCloud App as a novel smartphone application. This App reflects the development of the Chinese Rheumatism Data Center (CRDC), which provides not only a technical platform for the database and registry of rheumatic diseases (RDs) in China, but also a close tie between Chinese rheumatologists and patients with RDs. Throughout the past decade, CRDC has successfully built the world's largest nationwide database for RDs. A total of 2074 tertiary referral centers consisting of 8051 rheumatologists participated in the registry. RheumCloud App, which is representative of the success of CRDC, has played a central role in supporting patient cohort registration, biosample collection, and patient education. Based on the data of the Rhuem-Cloud App, three national key research projects have been funded and a series of research papers have been published. [ABSTRACT FROM AUTHOR]

The ammonia-hydrazine shutdown protection method is widely used in thermal power plants in China because of its good protective performance. However, the toxicity and safety of hydrazine have restricted its use in many power plants, and it is necessary to improve the shutdown protection techniques. In this paper, electrochemical impedance spectroscopy and potentiodynamic polarization curves were used to study the effect of hydrazine in water solutions of different pH values, adjusted with ammonia on the corrosion behavior of carbon steel. It was found that in the water solution without hydrazine, the corrosion resistance of a carbon steel electrode increased with raising the pH. When the pH value of water increased to 10.5, the impedance value of the carbon steel increased significantly, the corrosion current density decreased from 26.06 μA·cm−2 at pH 10.0 to 2.36 μA·cm−2, and the steel surface was passivated. Hydrazine had different effects on the electrochemical corrosion behavior of carbon steel in water solutions with various pH. When the pH of water was not higher than 10.0, hydrazine had a good corrosion inhibition effect on carbon steel. When the pH of water was not lower than 10.5, the addition of hydrazine inhibited the passivation of carbon steel and promoted the corrosion. The adsorption and substitutional oxidation of hydrazine in the anode region of carbon steel surface should be the reasons for the above phenomenon. [ABSTRACT FROM AUTHOR]

Solubility equilibria are relevant to many aspects of chemistry and chemical engineering. Studies on solubility phenomena are of importance in understanding chemistry and in the development of chemical technology. Solubility equilibria are especially useful for geochemists investigating the formation and evolution of natural salt deposits. China possesses an enormous variety of such resources, including salt lakes, underground brines, oil-field brines, and natural soda and borate deposits, etc. With the ongoing economic development of China, the exploitation and comprehensive utilization of these kinds of mineral resources are making great progress. Although much research on aqueous salt systems has been published, solubility equilibria studies have long been an active research field in China. This paper presents a review of solubility research on salt/water systems, encompassing more than 200 papers from Chinese researchers. [ABSTRACT FROM AUTHOR]

Over two decades from 1949 until the resumption of the diplomatic relations between these two countries in 1972, West German companies never gave up on the Chinese market despite substantial difficulties caused by Cold War frictions. This paper exams the payment transactions and terms of credits for financing industrial projects between the PRC and West German companies. [ABSTRACT FROM AUTHOR]

This paper presents the results of an investigation of the incorporation of Au within pyritic ore from the Qiucun epithermal Au deposit, China. The new data provide insights into the mode of occurrence of Au during fluid-rock interactions within epithermal systems. The distribution and mode of occurrence of Au within arsenian pyrite were investigated using a chemical and structural characterization-based approach combining laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) trace element analysis, megapixel synchrotron X‑ray fluorescence analysis (MSXRF), and atom probe tomography (APT). The resulting data indicate that invisible Au is present at elevated concentrations in the form of a homogeneous solid solution within As-rich pyrite domains, which yields Au concentrations that positively correlate with As. Arsenic-induced lattice defects, such as stacking faults and the expansion of the pyrite unit cell, provide evidence of the effect of As on the incorporation of Au into pyrite. The nucleation and crystallization of electrum preferentially occurred at the fluid-pyrite reaction interface or along fractures and grain boundaries within the pre-existing pyrite. This study indicates that changes in physicochemical conditions (e.g., temperature, pH, and sulfur fugacity) during fluid-pyrite interactions are key controls on the development of nanometer- or micrometer-scale clusters of gold. The systematic compositional and textural observations documented in this study provide new insights into the mechanisms responsible for the different modes of occurrence of Au (ionic vs. particulate) and enable us to further understand the processes involved in the formation of Au mineralization. [ABSTRACT FROM AUTHOR]

Given the evolving multimodal features in educational settings, modes other than language further enable the diversity in the realization of meanings and pedagogic goals. This paper explores modality in multimodal pedagogic materials for teaching English as a foreign language in China. Drawing upon the social semiotic approach to modality in visual media, this study provides a comparative analysis of modality markers in different elemental genres that constitute the macrogenre of a teaching unit, with a focus on explaining the underlying reasons for the different choices in terms of coding orientation. It is shown that different degrees of deviation from the accepted coding orientation are employed in different constituent genres of the macrogenre of a given text. [ABSTRACT FROM AUTHOR]

Kann eine Lehrmethode weltweit eingesetzt werden oder muss sie jeweils an lokale Bildungskontexte angepasst werden? In diesem Beitrag wird ein Forschungsprojekt von 2015 bis 2016 vorgestellt, in dem die aus Deutschland stammende Methode „Lernen durch Lehren" an der chinesischen Zhejiang-Universität getestet und evaluiert wurde. In der Methode „Lernen durch Lehren" (LdL) erarbeiten Lernende eigenständig Unterrichtsthemen und vermitteln den Lehrstoff in der Rolle der Lehrkraft. Aus den Forschungsergebnissen der Studie geht hervor, dass die Methode auch mit TeilnehmerInnen (TN), die geringe Erfahrungen mit kommunikativer Didaktik haben, erfolgreich angewendet werden kann. Insbesondere in den Bereichen Sprechfähigkeit und Hörverstehen konnten erhebliche Erfolge verzeichnet werden; der Sprechanteil der TN erhöhte sich im Pilotprojekt ebenso wie die Lernerautonomie und Informationskompetenz der TN stark. Jedoch führte die Unterrichtsvorbereitung zu einer hohen Arbeitsbelastung für die Studierenden, denen es an didaktischer Erfahrung mangelte. Auch kulturelle Konzepte wie der Gesichtsverlust und ein durch das chinesische Schulsystem geprägtes Verständnis der Lehrerrolle beeinflussten die Implementierung. In diesem Beitrag wird die Hypothese aufgestellt, dass das Implementationsdesign der Methode LdL für den Einsatz in China kultursensitiv angepasst werden muss. Can teaching methods be applied globally or do they have to be adapted to fit the specific cultural environment of the classroom? This paper discusses a research project at Zhejiang University where the method learning-by-teaching (LBT) was applied and assessed in the context of Chinese Higher Education in 2015/2016. In LBT classes, students take over tasks that are traditionally performed by teachers: They explore content independently, find ways of teaching the subject matter and enable student learning by correcting other students or giving them feedback. The project at ZJU revealed that learning-by-teaching can be beneficial in the Chinese context, even though the learners had little experience with communicative methods. LBT showed positive results especially in promoting speaking and listening comprehension, by enhancing autonomous learning and creating an active and collaborative learning atmosphere. But in the case study, the participants described problems understanding student-taught grammar sections. Generally, they found it hard to comprehend other student-teachers. As the students lacked teaching experience, they faced an increased preparation time. This paper suggests that the previous learning experience of the participants in the Chinese school system and their exposure to Chinese cultural values (regarding teacher roles for example) had an influence on the results of the study. Consequently, the implementation design of the method should be adapted culture-sensitively if used in China. However, the quick progression of the learners in terms of speaking and listening comprehension contradict the wide-spread idea of a static Chinese type of learner and show the potential of the method in the PRC. [ABSTRACT FROM AUTHOR]

This paper presents results of a German-Chinese comparative research project on the provision of services by non-profit organizations (NPOs) in the field of migration. It argues that NPOs and local governments deploy similar strategies in their joint attempt to tackle social problems, regardless of their political backgrounds. From a top-down perspective German and Chinese local governments show similar outsourcing modes, while from a bottom-up perspective NPOs show similar practices of network governance. [ABSTRACT FROM AUTHOR]

Unraveling the evolution of Mississippi Valley-type (MVT) hydrothermal system is crucial for understanding ore genesis and exploration. In this paper, we take the Wusihe Pb-Zn deposit in the western Yangtze Block (South China) as a case study, using detailed ore deposit geology, quartz in situ trace elements, and sulfides in situ S-Pb isotopes, to propose a new integrated model for the evolution of MVT hydrothermal system. Four hydrothermal stages were identified in the Wusihe ore district: (I) lamellar pyrite-sphalerite; (II) disseminated, stock-work, and brecciated sphalerite-galena; (III) massive galena, and (IV) veined calcite-bitumen. Within the most representative stage (stage II), Al concentrations in quartz (Q) increase from 8.46–354 ppm (mean 134 ppm) of Q1 to 171–3049 ppm (mean 1062 ppm) of Q2, and then decrease to 3.18–149 ppm (mean 25.4 ppm) of Q3. This trend indicates the role of acid-producing processes that resulted from sulfide precipitation and acid consumption by carbonate buffering. The occurrence of authigenic non-altered K-feldspar provides further evidence that the ore-forming fluids were weakly acidic with pH values of > ~5.5. Moreover, new bulk δ34S values of sulfides (+1.8 to +14.3‰) are overall lower than those previously reported (+7.1 to +20.9‰), implying that in addition to thermochemical sulfate reduction (TSR), bacterial sulfate reduction (BSR) may play an important role in the formation of S2–. In situ δ34S values show a larger range (–4.3 to +26.6‰), and significantly, varies within single grains (up to +12.3‰), suggesting mixing of two isotopically distinct S2– end-members produced by TSR and BSR. The diagenetic and hydrothermal early phase (stage I) sulfides were formed within a nearly closed system of BSR, whereas the formation of late phase (stage II and stage III) sulfides was caused by the input of hydrothermal fluids that promoted TSR. New galena in situ Pb isotopic ratios (206Pb/204Pb = 18.02–18.19, 207Pb/204Pb = 15.66–15.69, and 208Pb/204Pb = 38.14–38.39) suggest that the sources of mineralizing metals in the Wusihe deposit are mainly Proterozoic basement rocks. Hence, a multi-process model (i.e., basin-mountain coupling, fluid mixing, local sulfate reduction, in situ acid-producing and involvement of black shales and carbonate sequences) was responsible for the formation of the Wusihe deposit, while S2– was produced by both TSR and BSR, providing new insights into the evolution of MVT hydrothermal system. [ABSTRACT FROM AUTHOR]

This study uses sustainable development theory to analyze China's garment industry, which has been under pressure of high energy consumption, excess capacity and environmental pollution. The purpose of this work is to explore customized platform effectiveness on fashion design and production by the integration of clothing ceo-design (CED) and clothing life cycle evaluation. By cooperation and data analyses, garment companies come into being, which provides information for the study on customized platform effectiveness. Meanwhile, this paper begins with addressing the potential problems for fashion design, production and inventory management, making a distinction between garment virtual design (GVD)and personalized garment customization (PGC) and suggesting a useful computer-aided approach for fashion design and production process. The data and information were gathered from garment companies in China. This work presents the findings from case study research into sustainable improvements for fashion design and production in the garment industry; in this way, the level of customized platform may be compared and analyzed, which is a significant growth point of sustainable improvements for this research and practice domain. [ABSTRACT FROM AUTHOR]

[Ag6]4+ clusters are extremely rare in nature (only found in Ag-rich tetrahedrite group minerals). Due to their remarkable structures and some promising applications, a few synthesis phases that contain octahedral [Ag6]4+ clusters have been reported. However, the kinds of natural conditions that promote the formation of subvalent hexasilver clusters in tetrahedrite group minerals are still unclear. Kenorozhdestvenskayaite-(Fe), ideally Ag6(Ag4Fe2)Sb4S12□ is a new tetrahedrite group mineral containing a natural [Ag6]4+ cluster, found in the Yindongpo gold deposit, Weishancheng ore field, Henan Province, China. This new species occurs at the edges of galena crystals as anhedral grains of 2 to 20 μm in size and is associated with pyrargyrite, pyrrhotite, and siderite. Kenorozhdestvenskayaite-(Fe) is black in color with metallic luster. It is brittle with conchoidal fracture and has a calculated density of 5.329 g/cm3. The empirical formula calculated on the basis of cation = 16 apfu is M(2)Ag6M(1)(Ag2.41Cu1.20Fe1.84Zn0.71)Σ6.16X(3)(Sb3.82As0.01)Σ3.83S(1)S11.60S(2)□. It is cubic, with space group I 4 3m, a = 10.7119(6) Å, V = 1229.1(2) Å3, and Z = 2. Since kenorozhdestvenskayaite-(Fe) is a new tetrahedrite group mineral containing a natural [Ag6]4+ cluster, its structure is comparable to the synthetic ternary phosphide (Ag6M4P12) M 6 ′ . The presence of the unusual mineral assemblages, i.e., pyrrhotite and pyrargyrite, as well as the other keno-end-member tetrahedrites, indicates a low-fS2 state for the mineralization stage, probably a result of the fluid boiling process in an open system that likely contributed to the formation of S-deficient tetrahedrites. [ABSTRACT FROM AUTHOR]

A-type granites generally have much lower water, higher temperature, and incompatible element concentrations than I-type granitoids. Yet it remains unclear why I-A-type granitic complexes occur in convergent plate margins. Here we conduct geochemical analyses on apatite and mafic minerals from the late Cretaceous I-A-type granitic complex in Fuzhou area, SE China, aiming to decipher differentiation, fluid metasomatism, and degassing that primarily control the compositional diversity of felsic magmas. Apatites in both rock types are F-rich and show large H2O and δD variations, i.e., 341–3892 ppm H2O and –325 to +336‰ δD in I-type granitoids; 67–1366 ppm H2O and –251 to +1439‰ δD in A-type granites. H2O in apatite is negatively correlated with La/Sm and Sr/Y in the I-type granitoids, whereas it is positively correlated with Ce and total rare earth element (REE) concentrations in the A-type granites. Once H2O increases up to hundreds of ppm, both rock types show a rapid decrease of H2O/Ce, an increase of F/Cl, and extensive H isotope fractionation. Arfvedsonite occurs as a late crystallizing mineral in the A-type granite and has much higher contents of Na2O, K2O, F, and high field strength elements (HFSE) than hornblende in the I-type granitoids, indicating the addition of F-HFSE-rich alkaline fluids during its magmatic evolution. The consumption of arfvedsonite and formation of aegirine further indicate the role of fluid metasomatism and H2 degassing via a reaction of 3Na3Fe5Si8O22(OH)2 + 2H2O = 9NaFeSi2O6 + 2Fe3O4 + 6SiO2+5H2. The combined geochemical data demonstrate that the systematic differences in mineral assemblage, whole-rock composition, magma temperature, H2O content, and δD of apatite between the I- and A-type granites are likely attributed to varying degrees of differentiation, fluid metasomatism and magmatic degassing. The I-type granitoids experienced hornblende, biotite, plagioclase, K-feldspar, and apatite fractionation and close-system degassing. The A-type granite was likely formed from the I-type monzogranitic magma that was metasomatized by the mantle-derived F-HFSE-rich alkaline fluids to produce the peralkaline magma, which further experienced K-feldspar + plagioclase + biotite + apatite fractionation and open-system degassing. Further numerical estimation indicates that the primary magma of Fuzhou granitic complex contained ~3.0 wt% H2O, and the lower water content of A-type granite was likely attributed to strong degassing during its emplacement. Our results indicate that some peralkaline A-type granites can be generated from relatively water-poor I-type granitic magmas by fluid metasomatism and degassing. [ABSTRACT FROM AUTHOR]

To evaluate the ovarian reserve (OR) in women with antiphospholipid syndrome (APS), systemic lupus erythematosus (SLE), especially SLE-associated APS, and to determine the association between OR and clinical and laboratory parameters. We compared the antral follicle count (AFC), anticardiolipin antibody, and anti-Müllerian hormone (AMH), inhibin B (INHB), antiphospholipid (aPL) antibody, follicle-stimulating hormone (FSH), progesterone (P), testosterone (T), and estradiol (E2) among patients with primary APS (PAPS), SLE-APS, and SLE who were treated at Jinhua Central Hospital between 2017 and 2020. We conducted correlations and logistic regression analyses to identify the risk factors of OR failure in women with APS. Serum AMH were positively correlated with AFC and INHB in APS patients, and low AMH was independent risk factor for OR decline in APS patients. The ROC curve showed a high accuracy for AMH in the prediction of OR failure. Compared to healthy subjects (HS), patients with PAPS, SLE-APS, and SLE exhibited lower serum AMH, AFC, INHB, and E2 levels and higher FSH and levels (p<0.05). Of all the patients, those with SLE-APS manifested the lowest serum AMH, AFC, INHB, and E2 levels and the highest FSH levels (p<0.05). APS and SLE patients showed lower indications of OR, including AFC and AMH, compared to HS. SLE-APS patients also appeared to have a lower OR than either SLE or PAPS patients. [ABSTRACT FROM AUTHOR]

Ancient manganese (Mn) deposits are primarily characterized by the presence of Mn(II) carbonates that likely formed by the diagenetic reduction of precursor Mn(IV) oxides. As such, Precambrian sedimentary Mn deposits have been used as a line of evidence for the evolution of oxygen in Earth's surface environments. However, recent studies have shown that these Mn(II)-carbonates have the ability to directly accumulate within anoxic water columns, where free oxygen does not play a role in their formation. This alternative pathway casts uncertainty on the robustness of using ancient Mn deposits to constrain the redox fabric of the past marine water columns. Here, we investigate the Wafangzi Mn and Fe ore deposit from the 1.45 billion-year-old Tieling Formation, North China. The deposit contains Mn(II,III) mineral phases (hausmannite, braunite) as inclusions, or unreacted residues, trapped within Mn(II) carbonate (Ca-rhodochrosite). Some nodules and oolites of Mn(II) and Fe(II)-carbonate phases are also present and display a banded structure with concentric rings. Mn(III) oxide (manganite) is present in a paragenetic assemblage along with hematite and replacement textures with braunite. The negative carbon isotope composition (δ13C, –7‰ to –4‰) from Mn(II) carbonate samples in the Wafangzi Mn deposit which are distinct from that of contemporaneous seawater (~0‰), along with petrographic and speciation analyses, collectively suggest that the Mn(II,III)- and Fe(II)-bearing mineral phases formed through the diagenetic reduction of primary Mn(IV)/Fe(III) minerals coupled to the oxidation of organic matter. Therefore, the Wafangzi Mn deposit suggests the presence of sufficiently oxygenated marine waters, overlying anoxic ferruginous deeper waters with a transitional manganous water layer that could have driven the redox cycling of Mn, Fe, and C. Given the contemporaneous economic Mn deposits in the 1.45 Ga Ullawarra Formation in Western Australia, our findings imply the existence of a transient, and perhaps widespread, pulsed oxygenation event in the mid-Proterozoic oceans. [ABSTRACT FROM AUTHOR]

Elucidating metal transport agents is the key to understanding the genesis of deposits and tracking the locations of concealed orebodies. Here, we integrate H-O-S-Cu isotopic data from the shear-zone-hosted Lingyun Cu deposit, China, as a means to fingerprint metal transport agents. Sulfide mineralization can be divided into early and late stages, which consist of chalcopyrite + bornite + quartz veins and chalcopyrite + bornite + ankerite veinlets, respectively. Both δ18Ofluid and δD values of fluid inclusions hosted by quartz (δ18Ofluid: 0.5‰ to 9.9‰, δD: –103.9‰ to –60.1‰) and δ65Cu values of sulfides (–1.85‰ to +0.39‰) from the early stage progressively decrease from the southeastern to northwestern portions of the Lingyun deposit, whereas sulfide δ34S simultaneously shifts toward heavier values (–14.4‰ to 5.0‰). The δ34S and δ65Cu values of sulfides from the late stage have restricted ranges from –11.2‰ to –9.3‰ and –0.30‰ to 0.05‰, respectively. The possibilities of meteoric water addition, water-rock interaction, inter-mineral Cu partitioning, diffusion, and oxidation could be ruled out as reasons for having caused systematic H-O-S-Cu isotope variations. Vapor-liquid separation resulted in preferential incorporation of light Cu, H, and O isotopes into the vapor phase. The decrease in oxygen fugacity in the fluids resulted in a shift toward heavier δ34S values as fluid flowed outward. Vapor-phases are the dominant transport agents for Cu in the Lingyun deposit, which may be widely applicable to shear-zone-hosted deposits. The direction of progressively increasing δ65Cu, δD, and δ18O values and decreasing δ34S values allows identification of potential locations of concealed orebodies. [ABSTRACT FROM AUTHOR]

Scheelite (CaWO4) is an economically important W mineral in skarns that form when magmatic fluids exsolved from a granitic intrusion react with carbonate wall rocks. In the Fujiashan W skarn deposit, scheelite formed during four stages of the hydrothermal skarn development. We present cathodoluminescence (CL) images and in situ trace element and Sr-O isotope data of scheelite from these four stages, i.e., scheelite in prograde and retrograde skarn, quartz-sulfide veins, and late calcite replacements. Scheelite from prograde skarn and quartz sulfide veins are homogeneous and show oscillatory zoning textures in CL images, whereas scheelite from retrograde skarn and late carbonate stages display dissolution-reprecipitation and patchy textures. The brightness of CL textures decreases with a higher substitution of Mo. Molybdenum-rich scheelite (up to 2.1 wt%) is characterized by relatively high contents of Nb and Ta (up to 156 and 0.9 ppm, respectively), positive Eu anomalies, high-δ18O values (5.2 to 5.9‰), and relatively low-87Sr/86Sr values (0.70661 to 0.70727), and has grown in a system with a continuous supply of magmatic fluid. Molybdenum-poor scheelite (0.2 wt%) has low contents of Nb and Ta, negative Eu anomalies, low-δ18O values (4.2 to 4.3‰), and relatively high-87Sr/86Sr ratios (0.70748 to 0.70804). This type of scheelite formed in a system with a restricted flow of magmatic fluid during scheelite precipitation became increasingly depleted in elements that substitute into scheelite. The continued reaction of the magmatic fluid with the wall rocks and the precipitation of minerals from the fluid resulted in a systematic change of the δ18O and 87Sr/86Sr ratios. Chemical and isotopic variations in scheelite may reflect the pulsed flow of a magmatic fluid and do not require the involvement of different fluids or contrasting redox conditions. [ABSTRACT FROM AUTHOR]

High-Sr/Y granitoids in continental settings are sometimes erroneously regarded as the products derived from partial melting of thickened/delaminated mafic lower curst under relatively higher pressures (>1.5 GPa) in a collisional orogenic setting. In fact, multiple magmatic processes in the trans-crustal magma system, such as recycling of antecrysts, crustal assimilation, and fractional crystallization, can create or modify the primary "adakitic" signature. As a result, the generation of adakitic magmas in continental settings remains controversial from a bulk-rock perspective. Here, we address the origin of adakitic plutonic rocks through geochemical and textural characterization of rock-forming minerals in the pyroxene-bearing Zhuyuan granodiorite, West Qinling, China. The Zhuyuan granodiorite formed in a post-collisional setting and primarily consists of resorbed orthopyroxene, three types of clinopyroxene, amphibole, two types of plagioclases, K-feldspar, biotite, and quartz. Type-1 Cpx has high XMg (70.0–81.7). Type-2 Cpx displays normal zoning and decreasing XMg (80.9 to 71.5) from the core to rim. Type-3 Cpx is reversely zoned, where the rims have higher XMg (75.5–86.9), Ni, Cr, suggesting a recharge event. Orthopyroxene has high-Ni and -Cr contents, as well as high XMg (80.9–82.8), indicative of antecrysts that grew in mafic magma reservoirs. The injection of magmas from different sources is supported by sieve-textured plagioclase and crystal size distributions of non-poikilitic amphibole. Finally, non-sieve textured plagioclase, biotite, K-feldspar, and quartz are late-crystallized phases, indicative of an orthocrystic origin. The melts in equilibrium with these orthocrysts display significantly higher Sr/Y values than the magma batches that crystallized other mafic phases (i.e., amphibole, clinopyroxene, and orthopyroxene). Thus, we propose that the system involved an initial high-Sr/Y melts in equilibrium with the orthocryst assemblage was generated by water-fluxed melting of intermediate to felsic sources. The addition of low Sr/Y non-orthocrysts (e.g., amphibole and pyroxene) and associated melt diluted the original "adakitic signal" in the magma reservoir and drove the bulk composition to more mafic values. Consequently, the Zhuyuan pyroxene-bearing granodiorite represents a mixture of crystals with diverse origins and distinct magma batches of various compositions (from felsic to mafic compositions). Our study emphasizes that the origin of adakitic granitoids cannot be clearly deciphered without geochemical analysis of the constituent minerals. We also suggest that Sr/Y values in plutons should be cautiously used in paleo-crustal thickness estimates in collisional settings because of possible open system scenarios as described here. [ABSTRACT FROM AUTHOR]

The large Mo isotopic fractionations between diferent geological reservoirs make this isotopic system a potentially useful tool for constraining the origins of magmatism. However, the efect of magmatic diferentiation on Mo isotopes is still controversial. In this study, we obtained Mo isotope data for the Panzhihua gabbroic intrusion (i.e., including mineral separates of clinopyroxene, plagioclase, magnetite, and ilmenite). The whole-rock samples and mineral separates exhibit large Mo isotopic fractionations with δ98/95Mo values as follows: magnetite (–0.73‰ to –0.32‰) < clinopyroxene (–0.32‰ to –0.10‰) < ilmenite (0.06‰ to 0.36‰) < plagioclase (0.33‰ to 0.83‰). Iron-Ti oxides have Mo contents that are one order of magnitude higher than those of clinopyroxene and plagioclase. Mass balance calculations based on Mo isotopes and contents are consistent with an accumulated origin for the Panzhihua intrusion. Rayleigh fractionation modeling shows that the removal of magnetite and ilmenite results in significant Mo isotopic fractionation in the residual magma. Due to the low Mo contents of clinopyroxene and plagioclase, Mo isotopes are not significantly fractionated by the removal of these minerals. Therefore, our study highlights that fractionation of Fe-Ti oxides can cause considerable Mo isotopic fractionation; consequently, caution is needed when using Mo isotopes to infer magma origins. [ABSTRACT FROM AUTHOR]

A new mineral species, yuchuanite-(Y), ideally Y2(CO3)3·H2O, has been discovered and characterized in the Yushui Cu deposit in South China. The mineral occurs in bedded/massive ore and is associated with bornite, chalcopyrite, galena, sphalerite, bastnäsite-(Y), xenotime-(Y), anhydrite, and quartz. Individual crystals range in size from 30 to 300 μm. No twinning is observed. The mineral is colorless and transparent with a vitreous luster. The calculated density is 3.62 g/cm3. An electron microprobe analysis yields the empirical formula (based on 10 O apfu), (Y1.61Yb0.11Er0.11Dy0.08Ho0.03 Gd0.02Tm0.02)Σ1.99(CO3)3·H2O. Yuchuanite-(Y) is triclinic, with space group P 1 ¯ (# 2) , Z = 6, and unit-cell parameters a = 6.2134(3) Å, b = 8.9697(3) Å, c = 19.9045(7) Å, α = 91.062(3)°, β = 90.398(3)°, γ = 91.832(3)°, and V = 1108.54(8) Å3. The structure is constructed from (110) sheets of eight-coordinated Y polyhedra and C trigonal planar groups. All Y polyhedra are linked by shared edges. The Y atoms occupy six independent crystallographic sites of two different coordination types: [YO7(H2O)] and [YO8]. The chemical composition of yuchuanite-(Y) is similar to tengerite-(Y), Y2(CO3)3·2–3H2O, but is distinct in the crystal structure, such as crystal system, space group, and unit cell, from that of tengerite-(Y). The Y polyhedra of tengerite-(Y) are nine-coordinated, while those of yuchuanite-(Y) are eight-coordinated. Moreover, their structures could be both described as sheet structures built up from Y polyhedra and CO3 trigonal planar groups but link together in significantly different ways. Thus, yuchuanite-(Y) is not a polytype of tengerite-(Y) but is an independent mineral species. [ABSTRACT FROM AUTHOR]

Modified magnetite and hydrothermal apatite in banded iron formations (BIFs) are ideal minerals for studying hydrothermal and metamorphic processes and are applied to linking with high-grade Fe mineralization and metamorphism in iron deposits hosted by BIFs. In this study, we have investigated the geochemical composition of modified magnetite and hydrothermal apatite and in situ U-Pb geochronology on apatite from the Huogezhuang BIF-hosted Fe deposit in northeastern China. The magnetite in metamorphosed BIF is modified, locally fragmented, and forms millimeter- to micrometer-scale bands. The apatite is present surrounding or intergrowing with magnetite, has corroded surfaces, and contains irregular impurities and fluid inclusions, indicating that it has been partly hydrothermally altered. Original element compositions (e.g., Fe, Al, Ti, K, Mg, and Mn) of magnetite in BIFs have been modified during high-grade Fe mineralization and retrogressive metamorphism with temperature reduction and addition of acids. The hydrothermally altered apatite has been relatively reduced in the contents of Ca, P, F, La, Ce, Nd, δCe, δEu, and total REEs compared to non-altered apatite. The magnetite and apatite in low-grade BIFs are poorer in FeOT than those from the high-grade Fe ores, indicating that Fe is remobilized during the transition from BIFs to high-grade Fe ores. The magnetite and apatite in high-grade Fe ores are overgrown by greenschist-facies minerals formed during retrograde metamorphism, suggesting that the high-grade Fe mineralization may be related to retrogressive metamorphism. In situ U-Pb geochronology of apatite intergrown with magnetite and zircon LA-ICP-MS U-Pb dating at Huogezhuang deposit reveals that the BIF-hosted magnetite was altered and remobilized at ca. 1950–1900 Ma, and deposition of the BIF began during the Late Neoarchean. The changes of elements in the modified magnetite and diferent geochemical compositions of the altered and unaltered apatite confirm that the modified magnetite and hydrothermal apatite can be efective in tracing high-grade Fe mineralization and retrogressive metamorphism in BIFs. [ABSTRACT FROM AUTHOR]

Two types of turquoise, including homogeneous Cu-rich turquoise and oscillatory zoned turquoiseplanerite series, are recognized in association with quartz-barite veins hosted by Cambrian carbonaceous slates from western Hubei Province of China. Combined fluid inclusion and Raman micro-spectroscopic data reveal that turquoise-bearing barite-quartz veins contain three types of fluid inclusions (pure CH4-N2, carbonic-aqueous, and aqueous), suggesting the responsible fluid is of carbonic-aqueous composition with low oxygen fugacity. Pressure-corrected homogenization temperatures in quartz and barite show a range from 325 to 485 °C and 186 to 391 °C, respectively. Carbon, oxygen, and hydrogen isotopic data suggest that the mineral-forming fluids have a mixed metamorphic-organic affinity, in which the fluids have δ18O and δD values of 15.0 to 18.8‰ and –111 to –93‰, respectively. Generally, the formation of quartz-barite-turquoise veins could be triggered by prior metamorphic devolatilization, followed by the interaction of fluids with country rocks enriched in carbonaceous material, which resulted in the leaching of Cu, Fe, P, and Al from chalcopyrite, pyrite, magnetite, monazite, xenotime, apatite, feldspar, and muscovite in the wall rocks. Decomposition of the organic matter in the carbonaceous slates, caused by regional metamorphism and deformation, could also promote the concentration and transportation of necessary metals for the turquoise. Thus, we propose a new model and suggest that the turquoise gem deposits in western Hubei Province of China belong to the non-magmatic hydrothermal vein type deposit, not the previously proposed supergene origin. The turquoise-forming fluids were characterized by the coexistence of two immiscible fluids of non-magmatic affinity (i.e., moderate to high-temperature and low-salinity aqueous fluid and pure CH4-N2 fluid formed by interaction with carbonaceous slates). The bluish green homogeneous turquoise in the metamorphic quartz-barite-turquoise veins evolved toward the turquoise-planerite solid solution series as the metal-leaching capability of the aqueous fluids decreased. [ABSTRACT FROM AUTHOR]

The results of investigations into enrichment of precious metals in sphalerite and pyrite from the Maluntou epithermal gold deposit, China, are reported. The obtained data suggest intimate associations of Au- and Ag-bearing nanoparticles with chalcopyrite inclusions in sphalerite and pyrite. The origins of chalcopyrite inclusions involved different hydrothermal processes, including recrystallization-driven phase separation from parent chalcopyrite-sphalerite solid solutions and replacement of pre-existing pyrite in the presence of Cu-bearing fluids. The chalcopyrite blebs/lamellae follow sphalerite {111} planes, which define a shared sulfur layer for both chalcopyrite and sphalerite. This study indicates that mixing and boiling during the evolution of ore-forming fluids for the Maluntou deposit are key processes for the abnormal enrichment of precious metals in sphalerite and pyrite. The chalcopyrite micro/nano inclusions enhanced enrichment of precious metals in sphalerite provides new insights into the controls on the enrichment of precious metals in sulfides. [ABSTRACT FROM AUTHOR]

We present in situ LA-ICP-MS U-Pb dating of xenotime and monazite in assemblages with native gold and Au (Ag) tellurides from the Xiaoqinling lode gold district in central China. Composite xenotime and monazite grains formed through coupled dissolution-reprecipitation reactions reveal two discrete gold mineralization events. The first gold mineralization event, recorded by monazite (158.6 ± 3.3 Ma, Tera-Wasserburg lower intercept age) and xenotime cores (157.11 ± 0.83 Ma, weighted mean 206Pb/238U age), is characterized by the mineral assemblage of lingbaoite (AgTe3)-sylvanite ([Au,Ag]2Te4)-stützite (Ag5–xTe3)/native tellurium-sylvanite-stützite. The second gold mineralization event, recorded in the rims of xenotime (135.46 ± 0.93 Ma, weighted mean 206Pb/238U age), is characterized by the mineral assemblage of native gold-calaverite (AuTe2)-petzite (AuAg3Te2)-tellurobismuthite (Bi2Te3). Our study implies that the large-scale Jurassic mineralization event in eastern China, related to flat subduction of the paleo-Pacific plate beneath the eastern China continent, also caused widespread gold mineralization in the Qinling-Dabie Orogen, in addition to production of its world-class porphyry Mo deposits. The fact that only a few Jurassic gold mineralization ages have been reported before, may be due to the lack of suitable geochronometers to record the earlier Jurassic hydrothermal processes, which have been overprinted by the better-recognized Early Cretaceous gold mineralization event. This study also presents a rare example of xenotime compositional alterations and resetting of U-Pb ages induced by low to moderate salinity carbono-aqueous fluids at low temperatures. The textural relationships between gold minerals in contact with such composite xenotime crystals demonstrate that they could have precipitated before, coeval with, or after the dated domains. Since low to moderate salinity carbonoaqueous fluids are commonly involved in the formation of lode gold deposits, it is crucial to examine xenotime textures and recognize potential alteration textures before carrying out isotopic dating of xenotime collected from these deposits. Without prior compositional and textural characterization, attempts to date such composite crystals could yield mixed dates and meaningless ages. [ABSTRACT FROM AUTHOR]

From integrated textural and compositional studies of auriferous and barren pyrite/marcasite in the epithermal Axi gold deposit, China, we have identified a relationship between multiple gold mineralizing events, mafic magma recharge, and fluid-rock reactions. Three generations of pyrite (Py1–3) and four generations of marcasite (Mar1–4) record episodic gold mineralizing events, followed by silver-copper-lead-zinc-cadmium enrichment. The gold mineralizing events are recorded by high concentrations of subnanometer-sized gold in Py1, Py3, and Mar3 (max. = 147, 129, and 34 ppm, med. = 39, 34, and 12 ppm). Based on previous Re-Os age determinations of pyrite and U-Pb zircon ages of the andesitic wallrock, these gold events slightly postdate pulsed mafic magma recharge and represent the incursion of Au-As-S-rich magmatic volatiles into circulating meteoric water. Silver-Cu-Pb-Zn-Cd enrichment in Py2, Mar2, and Mar4 are consistent with quiescent degassing and gradual Ag-Cu-Pb-Zn-Cd enrichment in an evolved felsic magma. Barren Mar1 records the dominance of meteoric water and a limited magmatic fluid contribution. High-Co-Ni-V-Cr-Ti contents in porous cores of Py1 and Mar2 are attributed to wall rock alteration and dissolution-reprecipitation. The results provide convincing evidence that the metal budget (especially for Au, Ag, Cu, Pb, Zn, Sb) of the hydrothermal fluids and sulfides in epithermal systems are controlled by the influx of magmatic fluids and associated magma, whereas the enrichment of certain fluid-immobile elements, such as Co, Ni, V, Cr, and Ti, is caused in part by fluid-rock interaction. [ABSTRACT FROM AUTHOR]

Several important processes in the petrogenesis of granite are still debated due to a poor understanding of complex interactions between minerals during the melting and melt segregation processes. To promote an improved understanding of the mineral-melt relationships, we present a systematic petrographic and geochemical analysis for melanosome and leucosome samples from the Triassic Jindong migmatite, South China. Petrographic observations and zircon U-Pb geochronology indicate that the Jindong migmatite was formed through water-fluxed melting of the Early Paleozoic gneissic granite (437 ± 2 Ma) during the Triassic (238 ± 1 Ma), with the production of melt dominated by the breakdown of K-feldspar, plagioclase, and quartz. The Jindong leucosomes may be divided into lenticular and net-structured types. Muscovite, plagioclase, and K-feldspar in the net-structured leucosome show higher Rb and much lower Ba and Sr contents than those in the lenticular leucosome. This may be attributed to the elevation of Rb and decreasing Ba and Sr abundances in melts during the segregation process due to early fractional crystallization of K-feldspar and plagioclase. These leucosomes show negative correlation between εNd(t) and P2O5, reflecting increasing dissolution of low-εNd(t) apatite during the melting process. The continuous dissolution of apatite caused saturation of monazite and xenotime in melt, resulting in the growth of monazite and xenotime around apatite in the melanosome. This process led to a sharp decrease of Th, Y, and REE with increasing P2O5 in the leucosome samples. This complex interplay of accessory mineral reactions in the source impacts REE geochemistry and Nd isotope ratios of granites. As the granites worldwide exhibit similar compositional and isotopic patterns to the Jindong leucosomes, we suggest that both the melting and melt segregation processes strongly control the granitic melt compositions. [ABSTRACT FROM AUTHOR]

This note offers two short comments on Kai Lyu's paper published by AEL: A Convivium in 2015. The note highlights the fact that although the historical comparative perspective is very fruitful, Kai Lyu could have gone beyond the market/state divide, and could have better integrated the roles of stock exchanges in the political economy of China and the US in order to account for their different institutional transformations. [ABSTRACT FROM AUTHOR]

Halogens and other volatiles are widely recycled into the deep mantle by subduction and are key components to metasomatize the sub-continental lithospheric mantle (SCLM). Lamprophyres are well known to be rich in volatiles and are important for understanding the halogen characteristics of the metasomatized SCLM and/or the mobilization of halogens during the ascent of such volatile-rich, low-degree partial melts. The North China Craton (NCC) hosts lamprophyre dikes coeval with extensive thinning of the eastern NCC in the Mesozoic and generated from lithosphere metasomatized by multiple-stage subduction components. Here we report bulk-rock heavy halogens (Cl, Br, and I) of 16 lamprophyres from the eastern NCC. The bulk-rock halogen concentrations are overall very low (Cl = 58–170 μg/g, Br = 285–559 ng/g, and I <5 ng/g), comparable with depleted Mid-Ocean ridge basalts (N-MORBs). Volatile-rich minerals (e.g., amphibole and biotite) are abundant (20–30 vol%) in these lamprophyres, however, electron probe microanalyses (EPMA) data indicate that amphiboles are mainly rich in OH and F but display very low Cl concentrations (0.01–0.04 wt%). The bulk rock and amphibole data consistently indicate low abundances of heavy halogens in the lamprophyres, which is dificult to reconcile with the remarkable enrichment of fluid-mobile large ion lithophile elements such as Ba, Rb, and K. Based on low Cl/Nb and Br/Nb but high Ba/Nb and K/Nb ratios, the low halogen concentrations likely resulted from extensive volatile loss (>90%) during melt ascent. The low Cl concentrations in early-stage amphiboles (Mg# 60–64) further indicate that such loss would have occurred before amphibole crystallization at a depth of ~15 km. We thus propose that crystallization of early olivines and pyroxenes and reaction with surrounding mantle rocks likely induced volatile saturation and exsolution, leading to strong partitioning of the halogens into the exsolved aqueous volatile phases and thus the extensive loss of halogens from the rising melt. These results reveal that significant volatile loss of halogens not only occurs during surficial low-pressure eruption but also at much deeper levels in the crust, as also identified for some kimberlites. Consequently, it would be dificult to constrain the primitive halogen components of the mantle sources via lamprophyres or similar magmas. [ABSTRACT FROM AUTHOR]

Diverse fluid sources and complex fluid flow paths in skarn systems appear to be well documented. Nevertheless, in situ microanalysis of oxygen isotopes by secondary ion microprobe (SIMS) in skarn minerals can provide further high spatial resolution information on this complexity and the formation of skarns and associated ore deposits. In this study, we investigated the Haobugao skarn Zn-Fe-Sn deposit (0.36 M tonnes Zn) in the southern Great Xing'an Range, northeast (NE) China, and the associated Early Cretaceous Wulanba biotite granite. Based on drill hole logging, four early skarn phases are recognized: proximal red-brown garnet-hedenbergite exoskarn, central green garnet exoskarn, light brown garnet-diopside exoskarn, and distal pyroxene skarn. Oxygen isotope analyses of garnet, pyroxene, and other minerals from skarn, oxide, and quartz-sulfide stages were carried out using SIMS to determine the origin and evolution of the skarn-forming hydrothermal system. Garnet from exoskarn has a much wider range in δ18OVSMOW, between –8.1 and +6.0‰, than other stages and minerals. The estimated δ18O values of fluids in equilibrium with the Haobugao skarn vary widely from –5.1‰ to +8.9‰, suggesting that the skarn formed via episodic flux of magmatic fluid and meteoric water. Low δ18O values of cassiterite and quartz from quartz-sulfide stage rocks are +1.2 to +3.6‰, and +5.7 to +5.9‰, respectively, indicating significant contributions of meteoric water during deposition of Pb-Zn sulphides. Therefore, meteoric fluids were periodically present throughout most of the stages of skarn formation at Haobugao. [ABSTRACT FROM AUTHOR]

This article adopts an ecolinguistic approach to study the thematic choices in the General Debate statements by the US and China at the United Nations General Assembly (2017–2020) to reveal the eco-characteristics of the two countries' thematic choices and their impacts on the constructions of international relations. Findings suggest that, from the perspective of ecosophy, a significant proportion of the US's thematic choices are destructive to international relations, while China's thematic choices are mostly beneficial and ambivalent. The US's thematic choices are frequently used to portray "us versus them" and "America first", which displays a message of egocentrism instead of ecocentrism. China's thematic choices are typically used to show China's willingness to undertake global responsibility and to jointly work with other stakeholders to safeguard our planet, echoing China's global vision of "building a shared future for mankind". [ABSTRACT FROM AUTHOR]

Olivine compositions are widely used to constrain magmatic thermodynamic conditions such as magmatic temperature, oxygen fugacity, and H2O content. However, elemental diffusion may change the initial compositions and lead to large uncertainty on the estimation of these thermodynamic conditions. In this study, we conducted LA-ICP-MS elemental mapping and EPMA analysis of olivine phenocrysts and olivine-hosted spinel from the Jiagedaqi (JGD) alkaline basalts in northeast China to evaluate the influence of elemental difusion on olivine-composition-based geothermometry, oxybarometry, and hygrometry. The JGD olivines show normal Fo [Mg/(Mg + Fe) × 100 in moles] zoning, with cores having Fo of 77–87 and rims having Fo of 67–73. The constant P contents from core to rim indicate that these compositional zonings were caused mainly by difusion. Because Al is a slow-diffusing element and its content is relatively constant from core to rim, the temperature calculated by the Al-in-olivine thermometer is not influenced by elemental difusion and preserves the JGD olivine crystallization temperature up to 1150 °C. The temperatures calculated using the Sc/Y-in-olivine thermometer, the oxygen fugacity calculated using the olivine–spinel oxybarometer, and the H2O content calculated on the basis of Ca partitioning between olivine and melt are strongly influenced by the diffusion of Fo, Sc/Y, and Ca. However, the compositional plateaus in olivine cores, which were not influenced by elemental diffusion, preserve the magmatic temperature (1150 °C), oxygen fugacity (QFM+1.4), and H2O content (4 wt%) that applied during the formation of the JGD olivines. Together, these findings suggest that the mantle source of the JGD basalts was metasomatized by fluids released from the subducted slab. This study highlights that elemental difusion in olivine phenocrysts can strongly afect the application of olivine-composition-based geothermometers, oxybarometers, and hygrometers. However, primitive olivine cores that have not been influenced by difusion preserve the initial magmatic thermodynamic conditions. [ABSTRACT FROM AUTHOR]

Allanite is an important rare earth element (REE)-U-bearing mineral in granites, and it can act as a metal source for the formation of some hydrothermal uranium deposits and ion-adsorption REE deposits. To investigate the potential of allanite as a mineral probe of granite-related uranium mineralization processes and the formation of ion-adsorption REE deposits, we present textures, geochemistry, and in situ U-Pb isotope data for allanite from the fertile Changjiang granite associated with the Changjiang uranium ore field and barren Jiufeng granite in the Zhuguangshan batholith, South China. Alteration of allanite in the Changjiang granite is characterized by the altered domains with lower backscattered electron (BSE) intensities than the unaltered domains and replacement by other secondary minerals such as REE fluorocarbonates, calcite, fluorite, thorite, clay minerals, quartz, chlorite, and epidote. Crystals from the Jiufeng granite were partly replaced by the altered domains appearing darker in BSE images and minor REE fluorocarbonates. The darker domains of the Changjiang and Jiufeng allanite grains have higher Fe3+/(Fe3++Fe2+) ratios and U concentrations than those of the brighter domains, indicating that the alteration of allanite was probably related to more oxidized fluids. This study suggests that the Changjiang granite might have been subjected to the influx of F- and CO2-bearing fluids. The brighter domains of the Changjiang and Jiufeng allanite grains have weighted mean 207Pb-corrected 206Pb/238U ages of 156.7 ± 4.3 Ma and 161.6 ± 5.3 Ma, respectively, consistent with the corresponding zircon 206Pb/238U ages of 156.1 ± 1.4 Ma and 159.8 ± 1.8 Ma. The darker domains of the Changjiang allanite grains yield a weighted mean 206Pb/238U age of 141.4 ± 5.6 Ma, which overlaps within error the timing of a uranium mineralization event (~140 Ma) in the Changjiang uranium ore field and the age of a crustal extension event (140–135 Ma) in South China. The BSE images and elemental maps reveal that rare earth elements such as La and Ce have been released from the Changjiang allanites during alteration and were precipitated as REE-fluorocarbonates that are susceptible to chemical weathering, which sets the stage for the formation of an ion-adsorption REE deposit. Our study suggests that the regional crustal extension might have played an important role in the formation of both granite-related uranium and ion-adsorption REE deposits in South China, as it could have triggered alteration or breakdown of REE-U-bearing minerals in source rocks. [ABSTRACT FROM AUTHOR]

Numerous skarn-type Sn deposits have been identified in the Nanling Range (South China), of which the Shizhuyuan W-Sn-Bi-Mo, Xianghualing Sn, Jinchuantang Sn-Bi, and Hehuaping Sn deposits are the largest. The Xianghualing deposit, which is the focus of this study, hosts a resource of 0.17 Mt Sn grading 0.93–1.39 wt% SnO2. Whether the distal skarn-type mineralization and the cassiteritesulfide vein-type orebody in the Xianghualing district are genetically related to the Laiziling granitic pluton, which produced the proximal skarn-type Sn mineralization, however, is still unknown. The Xianghualing Sn mineralization occurs exclusively as cassiterite and has been subdivided into four ore-types: (1) lenticular proximal skarn ore (Cst I) containing the mineral assemblage cassiteritepyrrhotite-chalcopyrite-actinolite-wollastonite; (2) layered distal skarn ore (Cst II) containing the mineral assemblage cassiterite-pyrrhotite-chalcopyrite-actinolite; (3) vein cassiterite-sulfide ore (Cst III) distal from the skarn and associated granite containing the mineral assemblage cassiterite-arsenopyrite-pyrrhotite-muscovite-fluorite; and (4) veinlet Sn-Pb-Zn ore (Cst IV) distal from the skarn and associated granite containing the mineral assemblage cassiterite-galena-sphalerite-topaz-quartz. Here, we report the results of in situ laser ablation inductively coupled plasma mass spectrometric (LA-ICP-MS) U-Pb age determinations for garnet from the Xianghualing skarn and the above four types of cassiterite. Our age determinations indicate that there were two independent magmatic-hydrothermal events at ~160 and 156~150 Ma, both of which led to Sn mineralization. The first Sn mineralization event at ~160 Ma (Cst IV U-Pb ages of 159.6 ± 1.4 to 158.5 ± 0.8 Ma) is interpreted to have been associated with a speculative unexposed granitic pluton, which is coeval with the nearby Jianfengling granite intrusion. The second Sn mineralization event at 156~150 Ma (Cst I to Cst III U-Pb ages of 155.9 ± 0.7 to 152.3 ± 1.1 Ma and garnet U-Pb ages of 153.6 ± 7.6 to 151.5 ± 3.5 Ma) is genetically related to the adjacent Laiziling granitic intrusion (152.8 ± 1.2 Ma, zircon U-Pb age). This event was responsible for the bulk of the Sn resource (>95%). Our age determinations provide convincing evidence for superimposed Jurassic Sn mineralizing systems at Xianghualing. They also show the value of combining garnet and cassiterite U-Pb age determinations to constrain the timing of skarn and Sn mineralization and distinguish discrete Sn mineralizing events in a protracted metallogenic history. [ABSTRACT FROM AUTHOR]

Stratabound ore has been recognized as an end-member of porphyry copper systems, but pyrite chemistry has not been widely applied to linking stratabound ore with the related porphyry and skarn system. Stratabound ore is commonly developed around porphyry-skarn systems in eastern China, and is characterized by abundant colloform pyrite; however the origin of the colloform pyrite has been contentious. Xinqiao deposit is ideal for study of pyrite geology and geochemistry with the aim of elucidating formation of the stratabound ore and to decipher the evolution of pyrite compositions in a porphyry-skarn environment. The colloform pyrite paragenesis and S isotopes indicate that it formed during early skarn mineralization, based on its occurrence in stockwork veins cutting skarn minerals, and that it is replaced by later hypogene sulfides; the δ34S of colloform pyrite (average 6.12‰) is close to the δ34S value of both porphyry- (average 5.06‰) and skarn-type pyrite (average 4.65‰). The colloform texture formed as an aggregate of nanometer- or micrometer-sized (<0.2 μm) pyrite cubes produced by rapid crystallization from a high-fS2, low-temperature, and supersaturated fluid. Supersaturation of the fluid was probably produced by rapid decompression that triggered fluid boiling and cooling when the magmatic-hydrothermal fluid (derived from Cretaceous magma) flowed along the Devonian-Carboniferous unconformity. Subsequently, the colloform pyrite was replaced by later stage pyrite with distinctive trace elements (Co, Ni, and Se), indicating that the stratabound ore at Xinqiao formed from multiple pulses of magmatic-hydrothermal fluids derived from an Early Cretaceous stock. Co, Ni, and Se enrichment in porphyry- and proximal skarn-type pyrite suggests they formed at relatively high temperature, whereas the colloform pyrite shows trace element contents (Cu, Pb, Zn, Ag, and Bi) similar to those in distal skarn pyrite, suggesting that they may have formed in the same fluid environment. The trace element variations in pyrite from stratabound, skarn and porphyry ore probably resulted from decreasing fluid temperature and increasing pH away from the source. Our data, combined with previous studies, show that Co and Ni in pyrite increase toward porphyry and skarn ore, whereas As, Sb, Pb, Ag, and Bi are enriched in pyrite in distal stratabound ore, which extends for 1–2 km away from the intrusion. A plot of As/Se vs. Co discriminates the three ore types that occur associated with porphyry-skarn Cu systems in the Middle and Lower Yangtze belt (MLYB). These results indicate pyrite chemistry can be effective in discriminating the genesis of different deposit types related to porphyry-skarn systems and can potentially be used as a vectoring tool during exploration in the MLYB and elsewhere. [ABSTRACT FROM AUTHOR]

Kamafugites are strongly silica-undersaturated melts that are difficult to produce by partial melting of volatile-free peridotites but can be produced experimentally in the presence of CO2. Nevertheless, there is not yet direct evidence for a CO2-rich mantle source and the possible presence of recycled carbonates in the source of natural kamafugites. Marine carbonates have a heavier zinc isotopic composition (δ66Zn) than that of the mantle by up to 1.0‰, making zinc isotopes a sensitive tracer for recycled carbonates in the sources of mantle-derived magmas. Here we take Cenozoic kamafugites from the West Qinling orogen in China as an example to address the origin of this rare volcanic rock. The West Qinling kamafugites are strongly silica-undersaturated (SiO2 = 37.0 to 43.0 wt%) and have significantly higher δ66Zn (0.30‰ to 0.47‰) than that of the normal mantle (0.18 ± 0.05‰). No correlation between δ66Zn and MgO or SiO2 contents is observed, indicating that the high δ66Zn was not a result of magmatic differentiation. Modeling of melting indicates that even at extremely low degree (~0.5%), partial melting of a normal peridotitic source is still unlikely to produce silicate melts with δ66Zn values exceeding 0.30‰. Thus, the elevated δ66Zn of the West Qinling kamafugites demonstrates the presence of recycled carbonates in their mantle sources. Binary-mixing modeling suggests that the source contains ~5 to 15% recycled carbonates, which is supported by the positive correlation between δ66Zn and CaO/Al2O3. Overall, the West Qinling kamafugites represent the products of low-degree partial melting of a recycled carbonate-bearing peridotite source, which provides evidence for an important role of recycled carbonates in the origin of natural kamafugite suites. [ABSTRACT FROM AUTHOR]

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Due to the precise and continuous regulation of phase, holographic encryption based on metasurfaces and liquid crystals (LCs) has been proposed to encrypt the information by manipulating the wavelength, polarization, etc. However, the security cannot be fully guaranteed since the requirements of decoding methods for these schemes are generally not very strict and vulnerable for exhaustive attack. Furthermore, any part of the hologram stolen may lead to the disclosure of the hidden information regardless of the generation mode of phase delay or the selection of media material, so the security needs to be further improved. Here, inspired by Tiger Amulet, embodying the encryption consciousness of ancient China, we propose a simple but effective encryption method and design a "four-in-one" hologram based on photopatterned LCs. Specifically, the most important encrypted image can only be displayed when the four LC holograms in the same group are spliced into a whole according to the designed order. On the contrary, the camouflage information would be displayed if the holograms are placed in the optical path separately or spliced in wrong order. It is even more interesting that with the LC directors tilted with applied external voltages, the holographic efficiency of the LC hologram will change accordingly. This sets further demanding requirement on the decryption condition and thus increases the encryption security. With the advantages of simple design, high security, and low crosstalk, our encryption scheme has great potential in the fields of information hiding and image encryption. [ABSTRACT FROM AUTHOR]

The Hannuoba basalt, located in the northern margin of the North China Craton, is a typical intra-continental basalt with ocean island basalt-like geochemical features and has been extensively studied. However, its origin and deep processes, such as magma mixing and crystallization conditions, are still unclear. To further understand the mechanisms leading to the compositional heterogeneity and magmatic processes of Hannuoba basalt at crustal and/or mantle depth, in situ major element, trace element, and 87Sr/86Sr compositional heterogeneity of four representative plagioclase crystals in three Hannuoba tholeiite samples, as well as whole-rock major and trace element data, are reported. According to the petrographic characteristics, the basalts are divided into fine-grained and coarse-grained groups. The anorthite content in plagioclase of samples varies in a small range (56–64%), but the content of trace elements in plagioclase from the coarse-grained samples is generally higher than that of the fine-grained samples. Clinopyroxene-melt equilibrium thermobarometer and plagioclase-clinopyroxene magnesium and rare earth element exchange thermometers show that the magma for the two types of basalt was stored and crystallized at a similar depth, and crystallized within a 20 °C (fine-grained basalt) and 50 °C (coarse-grained basalt) temperature window, which may be a reason for the grain size diferences between the two types of basalts. We found that 87Sr/86Sr of all the studied plagioclase crystals varied from 0.70333 ± 0.00018 (2SE) to 0.70556 ± 0.00031 (2SE), a much large range than the whole rock of Hannuoba basalts reported previously and consistent with that of Cenozoic basalts in North China. Therefore, at least two kinds of melts with significant differences in isotope and minor heterogeneity in major and trace elements are injected into each magma plumbing system. The content of trace elements in the Hanuoba tholeiite is between the Hanuoba alkaline basalt and the lower crust, which may be explained by the mixing of the alkaline basalt and the lower crust, but the low 87Sr/86Sr (<0.704) characteristics of plagioclase cannot be derived from alkaline basalts, because trace element abundances in the plagioclase are not in equilibrium with the alkaline basalt. Therefore, we believe that the compositional heterogeneity of Hannuoba tholeiitic basalt is caused by the mixing of heterogeneous lower crust rather than different mantle-derived melts. In turn this indicates that the contribution of the continental lower crust to the continental basalt is more complicated than previously recognized. [ABSTRACT FROM AUTHOR]

Magmatic and metasomatic zircon occurs in many alkaline igneous rocks and both are potential economic reservoirs of Zr, and in some places, rare-earth elements. The Baerzhe deposit in China is an example of a system where both types of zircon occur. Previous studies recognized deuteric and variably altered magmatic zircon in a transsolvus miaskitic granite, as well as four types of metasomatic zircon in a transsolvus agpaitic granite. In this study, the relationships among, and origins of, zircon and how these relate to models for rare-metal mineralization are assessed. In situ backscattered electron (BSE) and cathodoluminescence (CL) imaging, Raman spectroscopy (including mapping), and chemistry of zircon from the agpaitic granite were conducted, combined with evaluation of published data on zircon from Baerzhe. Their textural, spectroscopic, and chemical characteristics suggest that the four types of metasomatic zircon in the agpaitic granite were not subjected to metamictization or intense alteration, with trace-element accommodation largely following a xenotime substitution mechanism. The most abundant type of metasomatic zircon in the agpaitic granite occurs in zircon-quartz pseudomorphs and exhibits comparable CL, Raman spectral, and chemical features to rare zircon that has partially replaced elpidite. This confirms that the pseudomorphs formed by complete replacement of elpidite. The pseudomorph zircon occurs in association with snowball quartz that contains inclusions of zircon, aegirine, and albite, and with secondary quartz containing aegirine. This is consistent with their coeval formation during Na metasomatism. The restriction of Na metasomatism to the agpaitic granite indicates that this event and the associated zircon formation resulted from early autometasomatism of the agpaitic phase. REE- and Be-rich zircon that replaced magmatic amphibole crystallized as a result of reaction with a REE- and Be-rich fluid that most likely was responsible for the later REE-Nb-Be mineralization that affected both the miaskitic and agpaitic granites. The miaskitic granite contains deuteric and altered magmatic zircon with diferent chemical characteristics to the four types of metasomatic zircon in the agpaitic granite. This suggests that secondary Zr mineralization in the miaskitic granite formed from diferent fluids to those that metasomatized the agpaitic granite and may also have resulted from autometasomatism. This study reveals a complex picture for the formation of zircon at Baerzhe, the character of which can vary significantly, both temporally and spatially. Such variable chemistry of the various types of zircon resulted not only from their diferent origins (magmatic vs. metasomatic), but also from localized water-rock interaction that involved multiple stages of fluids. Zircon in both the miaskitic and agpaitic phases was mainly the product of autometasomatism that was constrained to their parental granites. [ABSTRACT FROM AUTHOR]

Jingwenite-(Y), Y2Al2V2+(SiO4)O4(OH)4, the first V-HREE-bearing silicate mineral discovered in nature, is an abundant component of a sediment-hosted stratiform Cu (SSC) deposit, Yushui, South China. The mineral occurs in bedded/massive sulfide-bearing ore and is associated with bornite, chalcopyrite, galena, xenotime-(Y), nolanite, thortveitite, roscoelite, barite, and quartz. Optically, jingwenite-(Y) is biaxial (+), with a = 1.92(4), p = 1.95(2), Y = 1.99(3) (white light), and 2V (calculated) = 83°. The dispersion is medium with r < v, and the pleochroism is with X = light brown, Y = brown, Z = dark brown. The color, streak, luster, and hardness (Mohs) are light brown, yellowish gray, vitreous, and 4^-5, respectively. Jingwenite-(Y) is monoclinic, with space group I2la, Z = 4, and unit-cell parameters a = 9.4821(2) A, b = 5.8781(1) A, c = 19.3987(4) A, p = 90.165(2)°, and V = 1081.21(4) A3. The structure ofjingwenite-(Y) has chains of edge-sharing Al(V,Fe)-O octahedra and V(Ti)-O octahedra extending along the b-axis and linked by insular Si-O tetrahedra, leaving open channels occupied by HREEs. Jingwenite-(Y) is a new nesosilicate structural type. Sm-Nd dating and Nd isotope signatures ofjingwenite-(Y) reveal an epigenetic origin and suggest that HREEs and V were added to the SSC system via leaching of abundant heavy minerals in the footwall red sandstone by oxidized basinal brines. The abundance ofjingwenite-(Y) at Yushui indicates that it could potentially be a valuable resource for HREE and V. Moreover, HREE and V mineralization can also occur in the same sediment-hosted Cu mineral system. [ABSTRACT FROM AUTHOR]

The Aqishan-Yamansu belt in Eastern Tianshan (NW China) hosts several important Fe and Fe-Cu deposits, the origin of which is the subject of considerable debate. The coexistence of various types of ore-forming fluids makes it difficult to distinguish the genesis of the Fe-Cu deposits. We present detailed textural and compositional data on magnetite from the Paleozoic Shuanglong Fe-Cu deposit to constrain the formation of iron oxides and the evolution of the ore-forming fluids and thus define the genesis of the Fe-Cu ores. Based on the mineral assemblages and crosscutting relationships of veins, two mineralization stages were established, including the early Fe mineralization and late Cu mineralization stage. Three types of magnetite, i.e., platy (MA), massive (MB), and granular (MC) magnetite occur in the Fe mineralization. Backscattered electron (BSE) images identified display oscillatory zoning in an early hematite and transformational mushketovite phase (MA-I), characterized by abundant porosity and inclusions, as well as two later generations, including an early dark (MA-II, MB-I, and MC-I) and later light magnetite (MA-III, MB-II, and MC-II). The MA-I has extremely high W contents and mostly displays as micro-and invisible scheelite inclusions, which were probably caused by the W expulsion during mushketovitization. The texture and composition of magnetite suggest that the later light magnetite formed via dissolution and reprecipitation of the precursor dark magnetite, and the temperature and oxygen fugacity of fluids decreased over time. Our study also shows the MB-II magnetite and coexisting chlorite display synchronous oscillatory zoning, with the calculated temperature from 444 to 212 °C. Such variations could indicate the incursion of external low-temperature fluids with high salinity, which can dissolve the primary dark magnetite. This study provides a good example of using magnetite to trace the complex evolution and multiple sources of ore-forming fluids. [ABSTRACT FROM AUTHOR]

Porphyry-type Mo deposits have supplied most of the Mo to the world. However, the source of the Mo and the controls on its enrichment in such deposits is still a matter of great debate. In this study, we present in situ trace element and isotopic data for a giant porphyry Mo deposit (the Chalukou Mo deposit in NE China) and use these data to address these issues. Three primary paragenetic stages of mineralization were recognized at Chalukou: (Stage I) K-feldspar+quartz + minor pyrite (Py-I) + minor molybdenite (Mol-I); (Stage II) quartz + sericite + molybdenite (Mol-II) + pyrite (Py-II); (Stage III) quartz + chlorite + epidote + fluorite + pyrite (Py-III) + galena + sphalerite + minor chalcopyrite. The bulk of the molybdenite was deposited in Stage II. In situ S isotope analyses of the sulfide ores show that the S34S values vary from -5.2 to +7.8%o (mean = +2.9%o) and correspond to S34SH2S values from -2.4 to +3.3%o (mean = +1.1%o). These values are consistent with a magmatic source for the sulfur. In situ Pb isotope compositions of the sulfide ores are almost identical to those of the local Mesozoic granites and other magmatic-hydrothermal ore deposits in this region, suggesting a close genetic association between the Mo mineralization and felsic magmatism. Pyrite from the three stages of mineralization differs significantly in its trace element composition. The first generation, Py-I, has a high Cu content (8.7 ± 49.6 ppm; where the first value is the median and the second is the standard deviation) and Mo content (6.9 ± 3.8 ppm). Pyrite-II has the lowest Cu concentration (1.3 ± 2.1 ppm) and a relatively high Mo concentration (5 ± 128 ppm), and Py-III has a high Cu content (8.7 ± 37.1 ppm) but the lowest Mo content (0.05 ± 5.7 ppm). From this, we infer that pyrite recorded the chemical evolution in the Mo/Cu ratio of the ore fluid and that this ratio reached a maximum in Stage II, coinciding with the widespread saturation of the fluid in molybdenite. The evolution of the Mo/Cu ratio in pyrite implies that the fluid was undersaturated in chalcopyrite at the high temperature of Stage I, despite the Cu concentration of the fluid apparently being at its high level, and chalcopyrite only saturated later, at a lower temperature. Molybdenite, however, because of its lower solubility, saturated early (Stage I) and in the subsequent stage (Stage II) was supersaturated in the fluid. There is a significant enrichment of Mo in the syn-ore intrusions at Chalukou compared to the pre-ore monzogranite. The very low Sr/Y ratios for the Chalukou syn-ore intrusions, which are in sharp contrast to the high Sr/Y ratios of the pre-ore monzogranite and those of porphyries related to Cu deposits, suggest that fractional crystallization of plagioclase may have been a key factor in generating the syn-ore magmas. Molybdenum is a highly incompatible metal and will concentrate in the crust, and assimilation of old continental crust, therefore, may explain the Mo enrichment of the syn-ore intrusions and ultimately the formation of the giant Chalukou deposit. [ABSTRACT FROM AUTHOR]

Plate subduction links the Earth's surface and interior and may change the redox state of the Earth's mantle. Mantle wedges above subduction zones have high oxygen fugacity compared with other mantle reservoirs, but the cause is debated. Here we analyze high-pressure metamorphic rocks derived from ferromanganese pelagic sediments in the Qilian subduction complex, northwest (NW) China. We show that progressive metamorphism is a process of reducing reactions, in which Mn4+ is reduced to Mn2+. On the global scale, such reactions would release significant amounts of oxygen (~1.27 × 1012 g year−1), estimated from the global flux of MnO in sediments passing into subduction zones. This budget is sufficient to raise the oxygen fugacity of the mantle wedge, hence arc magmas, to a higher level than other mantle reservoirs. In contrast, ferric iron (Fe3+) enters hematite, aegirine, and garnet, without valence change and plays little role in the oxidation of the mantle wedge. Fe3+ remains stable to depths of >100 km but will transfer to the deeper mantle along with the subducting slab. The manganese reduction process provides a new explanation for high oxygen fugacity in the mantle wedge. [ABSTRACT FROM AUTHOR]

The Eastern Mediterranean region has been the subject of global power competition for many decades. Europe, Russia, and the United States have at different stages and in changing configurations sought to exercise influence in and power over various countries in the Eastern Mediterranean. But over the course of the past decade, the aforementioned triangle has been reshaped into a quadrangle. A new external actor has emerged and firmly planted its flag in the Eastern Mediterranean. The fourth country in question is the People's Republic of China. This article focuses on Greece, Turkey, and Israel as empirical examples of China's expanding footprint in the region. [ABSTRACT FROM AUTHOR]