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Zhang Y.,CAS Guangzhou Institute of Geochemistry | Zhang Y.,Central South University | Shao Y.-J.,Central South University | Wu C.-D.,304 Brigade of Hunan Nuclear Geology | And 2 more authors.
Ore Geology Reviews | Year: 2017

The Xinqiao Cu–S–Fe–Au deposit in the Tongling ore district, an important part of the Middle-Lower Yangtze River Valley metallogenic belt in eastern China, is located along the northern margin of the Yangtze Block. The deposit consists of two major mineralization types: stratiform and skarn (the genesis of the former is disputed). The more important stratiform orebody (90% of the total Cu, S and Fe reserves) has abundant garnet as the main gangue mineral, similar to the skarn orebody hosted in the intrusive contact. Garnets from the Xinqiao stratiform orebody range from pure andradite (And100) to And50Gro46, and can be divided into the early (Grt1) and late (Grt2) generation. Both generations contain low MnO (0.19–0.89%), wide range of Y/Ho (39.0–40.7 for Grt1, 29.8–67.9 for Grt2), and do not contain melt or fluid-melt inclusions, indicative of a magmatic-hydrothermal replacement origin. Grt1 and the Grt2 cores are grandite, whilst the Grt2 rims are mainly andradite with some grandite zones. Grandite is enriched in heavy rare earth elements (HREEs), and displays low ΣLREE/ΣHREE, LaN/YbN and U concentrations with negative Eu anomalies, whereas andradite is HREE-depleted, and displays high ΣLREE/ΣHREE, LaN/YbN ratios and U concentrations with positive Eu anomalies. The distinct trace element features suggest that the hydrothermal fluids for Grt1 and the Grt2 cores were of nearly neutral (pH), relatively oxidized and HREE-enriched, whereas those for the Grt2 rims had experienced episodic inflections between a mildly acidic, relatively reduced and HREE-depleted fluid and a nearly neutral, relatively oxidized and HREE-enriched fluid. Meanwhile, they also reveal that Grt1 and the Grt2 cores may have formed by diffusive metasomatism in a closed system, whereas the Grt2 rims may have formed by infiltration metasomatism in an open fracture system, possibly related to the unconformity that hosts the Xinqiao stratiform orebody. We propose that the Xinqiao stratiform orebody may have formed from Early Cretaceous magmatic-hydrothermal fluids associated with the Jitou stock, similar to the skarn-type orebodies in the district. © 2017 Elsevier B.V.

Zeng L.-J.,CAS Guangzhou Institute of Geochemistry | Zeng L.-J.,University of Chinese Academy of Sciences | Niu H.-C.,CAS Guangzhou Institute of Geochemistry | Niu H.-C.,Guangdong Provincial Key Laboratory of Mineral Physics and Materials | And 3 more authors.
American Mineralogist | Year: 2017

Although thermal lattice expansion is a well-documented nature of crystals, including zircon and zircon-type minerals, chemical lattice expansion of natural mineral is rarely reported. Here we present a comprehensive investigation on three types of natural zircon that records the evolution of the granitic system in Xiangshan, North China, and shows expanding crystallographic parameters induced by chemical incorporation instead of thermal expansion. Prismatic and oscillatory-zoned zircon grains (Type-1A), crystallized early in the granitic magma at high temperatures in a volatile-undersaturated environment, have the smallest lattice parameters (a = 6.603 Å, c = 5.971 Å). Prismatic and altered zircon grains (Type-1B), formed under volatile-saturated conditions and in the presence of F-rich fluid with numerous thorite and xenotime inclusions, have intermediate lattice parameters (a = 6.649 Å, c = 6.020 Å). Pyramidal zircon grains (Type-2), formed in a subsolvus granitic system at relatively low temperatures and coexisted with fluid inclusions, have the biggest lattice parameters (a = 6.677 Å, c = 6.010 Å). Trace elements, including Hf, Th, Ti, Y, and REE, and volatiles content, increase in the structure of zircon from the early to late magmatic origin, which is consistent with the expansion of the lattice parameters. The occurrence of the three zircon types in the Xiangshan arfvedsonite granites is interpreted to reflect the progressive fractionation of granitic melt from hypersolvus to subsolvus conditions. Therefore, we conclude that the lattice expansion of zircon in this study results from chemical incorporation of trace element and volatile components during the magmatic to hydrothermal evolution of granitic magma. Besides, the textural and compositional evolution of zircon can be used as efficient indices for the fractionation and evolution of A-type granitic system. © 2017 by Walter de Gruyter Berlin/Boston.

Yang W.-B.,CAS Guangzhou Institute of Geochemistry | Yang W.-B.,Guangdong Provincial Key Laboratory of Mineral Physics and Materials | Niu H.-C.,CAS Guangzhou Institute of Geochemistry | Niu H.-C.,Guangdong Provincial Key Laboratory of Mineral Physics and Materials | And 4 more authors.
Journal of Asian Earth Sciences | Year: 2015

Large-scale Mesozoic volcanisms in the Great Xing'an Mountains (GXM), northeastern (NE) China, are being extensively interested recently. However, the petrogenesis and geodynamic implications of these volcanic rocks are still on controversy. In this study, geochronology and geochemistry of the intermediate and felsic volcanic rocks of Late Mesozoic from the southern GXM was investigated. Zircon U-Pb geochronology yields 206Pb/238U ages ranging from 154.3 ± 1.7 Ma to 127.0 ± 2.4 Ma for the eight selected volcanic rocks, where the major period of the Mesozoic volcanisms is constrained during the Early Cretaceous. The presented volcanic rocks are andesite-trachydacite-rhyolite and show calc-alkaline to shoshonitic features. They have elevated incompatible trace element concentrations and significantly negative Nb-Ta-Ti and positive Pb anomalies, which display characteristics of typical subduction-related magmas rather than within-plate magmatic signature. Sr-Nd isotopic data indicate that their magma sources were mixed with proportions of old crustal components. Geochemical features, therefore, indicate that the intermediate and felsic shoshonitic magma was plausibly derived from partial melting of the subduction-modified lithospheric mantle and thickened lower crust, respectively, induced by delamination and/or asthenosphere upwelling in extensional setting. Combined with the tectonic evolution of the Great Xing'an area, we propose a hypothesis that the large-scale Mesozoic volcanisms in NE China were controlled by the transition of regional stress from southward to westward, which are induced by the changes of tectonic regimes from the previous Mongol-Okhotsk subduction to the succeeding paleo-Pacific subduction during Late Mesozoic. © 2015 Elsevier Ltd.

Xiande X.,CAS Guangzhou Institute of Geochemistry | Xiande X.,Guangdong Provincial Key Laboratory of Mineral Physics and Materials | Jianbo W.,Wuhan University | Xiangping G.,Central South University | And 2 more authors.
Acta Geochimica | Year: 2016

The mineralogy of shock vein matrix in the Suizhou meteorite has been investigated by optical and transmission electron microscopy. It was revealed that the vein matrix is composed of majorite-pyrope garnet, magnesiowüstite, and ringwoodite, with FeNi–FeS intergrowths. The observation and character of ring-like selected electron diffraction (SAED) patterns indicate that the idiomorphic garnet crystals in the vein matrix have different orientations. The polycrystalline nature of magnesiowüstite is also confirmed by a ring-like SAED pattern. Both garnet and magnesiowüstite crystals showed sharp diffraction spots, signifying the good crystallinity of these two minerals. The SAED pattern of cryptocrystalline ringwoodite shows only diffuse concentric diffraction rings. FeNi metal and troilite (FeS), which were molten during the shock event, occur in the matrix as fine eutectic FeNi–FeS intergrowths filling the interstices between garnet and magnesiowüstite grains. Based on the phase diagram of the Allende chondrite and the results of this TEM study, it is inferred that majorite-pyrope garnet first crystallized from the Suizhou chondritic melt at 22–26 GPa, followed by crystallization of magnesiowüstite at 20–24 GPa, and then ringwoodite at 18–20 GPa. The eutectic intergrowths of FeNi-metal and troilite are proposed to have crystallized during meteorite cooling and solidified at the last stage of vein formation. © 2016, Science Press, Institute of Geochemistry, CAS and Springer-Verlag Berlin Heidelberg.

Niu J.,China University of Mining and Technology | Niu J.,Guangdong Provincial Key Laboratory of Mineral Physics and Materials | Shen S.,China University of Mining and Technology | Zhou L.,China University of Mining and Technology | And 4 more authors.
RSC Advances | Year: 2016

Anatase microspheres composed of porous single crystals were successfully synthesized via a facile route without preseeding treatment and then further modified using a surface hydrogenation process. The porous materials obtained exhibit excellent photocatalytic activity and good recyclability leading to great potential in practical applications. © 2016 The Royal Society of Chemistry.

Yuan P.,CAS Guangzhou Institute of Geochemistry | Yuan P.,Guangdong Provincial Key Laboratory of Mineral Physics and Materials | Tan D.,Southwest University of Science and Technology | Annabi-Bergaya F.,CNRS Center for Research on Divided Matter
Applied Clay Science | Year: 2015

Halloysite is a natural nanosized tubular clay mineral that has many potentially important uses in different industrial fields. In this paper, the key structural characteristics and properties of halloysite and their related applications are comprehensively reviewed. Research advances on halloysite, especially those from the past 20. years, are summarized with some critical comments. Attention is mainly paid to the structure and morphology of halloysite and their changes, the formation of tubular structures, the physicochemical properties, the surface chemical modifications, and the halloysite-based advanced materials and some related applications. Additionally, future prospects and key problems to be solved in halloysite studies are discussed. This review shed new light on both fundamental and applied studies that focused on halloysite. © 2015 Elsevier B.V.

Zhou X.,Huaqiao University | Jing G.,Huaqiao University | Lv B.,Huaqiao University | Zhou Z.,Huaqiao University | Zhu R.,Guangdong Provincial Key Laboratory of Mineral Physics and Materials
Chemosphere | Year: 2016

Highly active Fe/Ni bimetallic nanocomposites were prepared by using the liquid-phase reduction method, and they were proven to be effective for Cr(VI) removal coupled with US irradiation. The US-assisted Fe/Ni bimetallic system could maintain a good performance for Cr(VI) removal at a wide pH range of 3–9. Based on the characterization of the Fe/Ni nanoparticles before and after reaction, the high efficiency of the mixed system could attribute to the synergistic effects of the catalysis of Ni0 and US cavitation. Ni0 could facilitate the Cr(VI) reduction through electron transfer and catalytic hydrogenation. Meanwhile, US could fluidize the Fe/Ni nanoparticles to increase the actual reactive surface area and clean off the co-precipitated Fe(III)-Cr(III) hydroxides to maintain the active sites on the surface of the Fe/Ni nanoparticles. Thus, compared with shaking, the US-assisted Fe/Ni system was more efficient on Cr(VI) removal, which achieved 94.7% removal efficiency of Cr(VI) within 10 min. The pseudo-first-order rate constant (kobs) in US-assisted Fe/Ni system (0.5075 min−1) was over 5 times higher than that under shaking (0.0972 min−1). Moreover, the Fe/Ni nanoparticles still have a good performance under US irradiation after 26 days aging as well as regeneration. © 2016 Elsevier Ltd

Li N.-B.,CAS Guangzhou Institute of Geochemistry | Li N.-B.,University of Chinese Academy of Sciences | Niu H.-C.,CAS Guangzhou Institute of Geochemistry | Niu H.-C.,Guangdong Provincial Key Laboratory of Mineral Physics and Materials | And 4 more authors.
Journal of Asian Earth Sciences | Year: 2015

A-type magmatism is an effective lithoprobe for constraining the tectonic evolution of orogenic belts. In this study, we have identified two episodes of Late Paleozoic A-type magmatism in Qunjisayi, western Tianshan. Zircon U-Pb geochronology has yielded Late Carboniferous (rhyolites, 306 ± 2 Ma)- and Early Permian (granites, 296 ± 3 Ma) ages. Both the Qunjisayi rhyolites and granites have depleted Sr-Nd-Hf isotopic compositions, moderate A/CNK ratios (0.91-1) and negative Nb and Ta anomalies. They are also characterized by high K2O + Na2O (8.72-10.6 wt.%), FeOT/(FeOT + MgO) (0.86-0.99) and Y/Nb (1.42-2.34) values, similar to those of typical A2-type granitoids. The Qunjisayi rhyolites may have been formed by partial melting of a juvenile calc-alkaline granitic crustal source induced by subduction roll-back in shallow depth. The succeeding Qunjisayi granites were likely to be derived from a lower crustal source that contains depleted mantle-derived components. Asthenospheric mantle upwelling, triggered by post-subduction slab break off, may have been important in the Qunjisayi granites formation. We conclude that the Late Paleozoic Qunjisayi A-type magmatism was genetically linked to the geodynamic transformation from late subduction to collision. © 2015 Elsevier Ltd.

Yu W.,CAS Guangzhou Institute of Geochemistry | Yu W.,University of Chinese Academy of Sciences | Yu W.,Guangdong Provincial Key Laboratory of Mineral Physics and Materials | Yuan P.,CAS Guangzhou Institute of Geochemistry | And 14 more authors.
Journal of Hazardous Materials | Year: 2015

Hierarchically porous diatomite/MFI-type zeolite (Dt/Z) composites with excellent benzene adsorption performance were prepared. The hierarchical porosity was generated from the microporous zeolite coated at the surface of diatom frustules and from the macroporous diatomite support. A facile NaOH etching method was employed for the first time to treat the frustule support, followed by hydrothermal growth of MFI-type zeolite at the surface of frustules previously seeded with nanocrystalline silicalite-1 (Sil-1). NaOH etching enlarged the pores on diatom frustules and further increased the coated zeolite contents (Wz). The central macropore size of the diatom frustules increased from approximately 200-500nm to 400-1000nm after NaOH etching. The Wz could reach 61.2%, while the macroporosity of the composites was largely preserved due to more voids for zeolite coating being formed by NaOH etching. The Dt/Z composites exhibited higher benzene adsorption capacity per unit mass of zeolite and less mass transfer resistance than Sil-1, evaluated via a method of breakthrough curves. These results demonstrate that etching of a diatomite support is a facile but crucial process for the preparation of Dt/Z composites, enabling the resulting composites to become promising candidates for uses in volatile organic compounds emission control. © 2014 Elsevier B.V.

Cheng Y.,Northeastern University China | Huang F.,Northeastern University China | Li W.,Northeastern University China | Liu R.,Northeastern University China | And 2 more authors.
Construction and Building Materials | Year: 2016

High-silicon iron tailings, which have been mechanochemically activated, was used for the preparation of concrete as a supplementary cementing material to substitute cement (by 10%, 20%, 30% and 40% respectively) based on their composition, particle sizes and pozzolanic activity. With the aid of tests, this paper discusses the effects of the tailings on the compressive strength of concrete. Tests show that with an increase in substitution rate of cement in the tailings, the compressive strength of concrete tends to decrease, and when the substitution rate is at 10%, 20% and 30% respectively, the compressive strength of concrete is measured up to the design requirement; if an appropriate amount of water reducing admixture is added while cement is substituted by tailings with a substitution rate of 10%, 20%, 30% and 40% respectively, the compressive strength of concrete is also measured up to the design requirement. The research result demonstrates that as far as the compressive strength concerned, it is feasible to use mechanochemically activated high-silicon iron tailings as a supplementary cementing material to partly substitute cement in concrete. © 2016 Elsevier Ltd. All rights reserved.

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