33 results on '"Weidong Sun"'
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2. Secondary hemophagocytic syndrome in an acquired immunodeficiency syndrome and Alpha-thalassemia patient infected with Talaromyces marneffei: A case report and literature review
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Qingqing Wu, Yixiu Yu, Shenhong Feng, Bingqian Fang, Renzhi Zheng, Weidong Sun, and Jianzhi Zhao
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Hemophagocytic syndrome ,Thalassemia ,Talaromyces marneffei ,Human immunodeficiency virus ,Infectious and parasitic diseases ,RC109-216 - Abstract
Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disease characterized by a hyperinflammatory syndrome and impairment of multiple organ systems. Talaromycosis marneffei (TSM) is an opportunistic infection mostly found in immunosuppressed populations, such as those with acquired immunodeficiency syndrome (AIDS), and is prevalent in southern China. However, HLH secondary to TSM is extremely rare and has only been reported in isolated cases. A 30-year-old patient with recurrent high fever and progressive cytopenia was diagnosed with HLH secondary to disseminated TSM with AIDS and Alpha-thalassemia. The patient remained in sustained remission without recurrence after effective treatment with antifungals and glucocorticoids.
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- 2024
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3. Study on corrosion law and characteristics of composite modified basalt fiber concrete in acid environment
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Zhenshan Wang, Weidong Sun, Runan Yang, Junlong Lu, and Xiaolei Li
- Subjects
Sewage environment ,Concrete ,Composite modification ,Durability ,Corrosion mechanisms ,Polymers and polymer manufacture ,TP1080-1185 - Abstract
The deterioration of concrete materials in the sewage environment is prominent, significantly shortening the structure's service life. Based on the composite modification method, modified basalt fiber high-durability concrete is proposed to solve the problem of insufficient material durability in the sewage environment. The acid environment erosion test was carried out for the modified concrete materials. The macroscopic performance indexes were obtained, such as apparent corrosion characteristics, water absorption rate and compressive strength. The corrosion mechanism and deterioration law of concrete materials under an acid environment were revealed by combining the analysis of the fine structure and corrosion product composition. The results show that the hydration reaction of the modified concrete was adequate. The generation of C–S–H gel and Ca(OH)2 increased significantly. The porosity was reduced by 40%, and the initial strength was increased by 12%. After 240d corrosion, the strength of ordinary concrete was degraded by 41%. The degradation rate of modified concrete was 26%, its residual strength was 1.4 times that of ordinary concrete, and its corrosion-resistant ability was greatly improved. Based on the experiment, the corrosion resistance mechanism analysis was carried out, and it was found that the inorganic aluminium salt compound salt crystal expansion modification effect is better than the sodium methyl silicate reticulated resin film modification. However, after double doping, the corrosion resistance is reduced instead, and it is recommended that inorganic aluminium salts be preferred as anti-corrosion and anti-seepage adding materials. The research results of this paper can better enhance the acid environment erosion resistance of concrete, engineering application prospect is good.
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- 2023
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4. Corrigendum to 'Identification of Frataxin as a regulator of ferroptosis' [Redox Biol. 32 (2020) 101483]
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Jing Du, Yi Zhou, Yanchun Li, Jun Xia, Yongjian Chen, Sufeng Chen, Xin Wang, Weidong Sun, Tongtong Wang, Xueying Ren, Xu Wang, Yihan An, Kang Lu, Wanye Hu, Siyuan Huang, Jianghui Li, Xiangmin Tong, and Ying Wang
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Medicine (General) ,R5-920 ,Biology (General) ,QH301-705.5 - Published
- 2023
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5. Unradiogenic Pb isotopic compositions of late Archean lower continental crust
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Weidong Sun and William F. McDonough
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Geology ,QE1-996.5 - Published
- 2023
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6. The evolution of the Magma Ocean and the formation of the habitable Earth
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Weidong Sun and Xiuqi Shang
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Geology ,QE1-996.5 - Published
- 2022
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7. An emerging plume head interacting with the Hawaiian plume tail
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Lipeng Zhang, Zebin Cao, Robert E. Zartman, Congying Li, Saijun Sun, Lijun Liu, and Weidong Sun
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Science (General) ,Q1-390 - Abstract
The Hawaiian-Emperor seamount chain has shown two subparallel geographical and geochemical volcanic trends, Loa and Kea, since ∼5 Ma, for which numerous models have been proposed that usually involve a single mantle plume sampling different compositional sources of the deep or shallow mantle. However, both the dramatically increased eruption rate of the Hawaiian hotspot since ∼5 Ma and the nearly simultaneous southward bending of the Hawaiian chain remain unexplained. Here, we propose a plume-plume interaction model where the compositionally depleted Kea trend represents the original Hawaiian plume tail and the relatively enriched Loa trend represents an emerging plume head southeast of the Hawaiian plume tail. Geodynamic modeling further suggests that the interaction between the existing Hawaiian plume tail and the emerging Loa plume head is responsible for the southward bending of the Hawaiian chain. We show that the arrival of the new plume head also dramatically increases the eruption rate along the hotspot track. We suggest that this double-plume scenario may also represent an important mechanism for the formation of other hotspot tracks in the Pacific plate, likely reflecting a dynamic reorganization of the lowermost mantle. Public summary: • Hawaiian hotspot track displays two subparallel isotopic trends since 5 Ma. • This is coeval with increased eruption rate and southward bending of the track. • These data support a new plume head emerging next to the old Hawaiian plume. • Our double-plume model may represent a new mechanism for hotspot evolution.
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- 2023
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8. Fragments of archean cratonic lithosphere mantle at large
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Weidong Sun and Fanfan Tian
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Geology ,QE1-996.5 - Published
- 2022
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9. How will volcanic ash from the Tonga volcano eruption perturbate marine carbon cycle?
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Xiaole Sun and Weidong Sun
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Geology ,QE1-996.5 - Published
- 2022
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10. Enhanced cooling of the mantle by the onset of modern plate tectonics
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Weidong Sun
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Geology ,QE1-996.5 - Published
- 2022
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11. Water in coesite: Incorporation mechanism and operation condition, solubility and P-T dependence, and contribution to water transport and coesite preservation
- Author
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Wei Yan, Yanyao Zhang, Yunlu Ma, Mingyue He, Lifei Zhang, Weidong Sun, Christina Yan Wang, and Xi Liu
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Coesite preservation ,FTIR ,New IR experimental Protocol ,Anhydrous minerals ,P-T dependence of water solubility ,Water-incorporation mechanism ,Geology ,QE1-996.5 - Abstract
A series of coesite, coexisting with or without a liquid phase, was synthesized in the nominal system SiO2–H2O at 800–1450 °C and 5 GPa. Micro-Raman spectroscopy was used to identify the crystalline phase, electron microprobe and LA-ICP-MS were employed to quantify some major and trace elements, and unpolarized FTIR spectroscopy was applied to probe the different types of hydrogen defects, explore water-incorporation mechanisms and quantify water contents. Trace amounts of Al and B were detected in the coesite. Combining our results with the results in the literatures, we have found no positive correlation between the Al contents and the “Al”-based hydrogen concentrations, suggesting that previously proposed hydrogen-incorporation mechanism H+ + Al3+ ↔ Si4+ does not function in coesite. In contrast, we have confirmed the positive correlation between the B contents and the B-based hydrogen concentrations. The hydrogen-incorporation mechanism H+ + B3+ ↔ Si4+ readily takes place in coesite at different P-T conditions, and significantly increases the water content at both liquid-saturated and liquid-undersaturated conditions. For the SiO2–H2O system, we have found that type-I hydrogarnet substitution plays a dictating role in incorporating water into coesite at liquid-saturated condition, type-II hydrogarnet substitution contributes significantly at nearly dry condition, and both operate at conditions in between. The water solubility of coesite, as dictated by the type-I hydrogarnet substitution, positively correlates with both P and T, cH2O = −105(30) + 5.2(32) × P + 0.112(26) × T, with cH2O in wt ppm, P in GPa and T in °C. Due to its low water solubility and small fraction in subducted slabs, coesite may contribute insignificantly to the vertical water transport in subduction zones. Furthermore, the water solubility of any coesite in exhuming ultra-high pressure metamorphic rocks should be virtually zero as coesite becomes metastable. With an adequately fast water-diffusion rate, this metastable coesite should be completely dry, which may have been the key factor to the partial preservation of most natural Coe. As a byproduct, a new IR experimental protocol for accurate water determination in optically anisotropic nominally anhydrous minerals has been found. Aided with the empirical method of Paterson (1982) it employs multiple unpolarized IR spectra, collected from randomly-orientated mineral grains, to approximate both total integrated absorbance and total integrated molar absorption coefficient. Its success relies on a high-level orientation randomness in the IR analyses.
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- 2021
- Full Text
- View/download PDF
12. Trace element characteristics of pyrite in Dongguashan Cu (Au) deposit, Tongling region, China
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Jiancheng Xie, Likai Ge, Lin Qian, Quanzhong Li, and Weidong Sun
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Laser ablation ICP-MS ,Trace elements ,Pyrite ,Dongguashan Cu (Au) deposit ,Tongling region ,Geology ,QE1-996.5 - Abstract
The Dongguashan deposit is the largest and deepest Cu (Au) deposit in the Tongling region, eastern China. The presence of skarn and stratiform ore bodies in the same system of the Dongguashan deposit has caused much debate as to whether the mineralization was associated with magmatic-hydrothermal or sedimentary origin. In this study, in situ (LA-ICP-MS and EPMA) elemental compositions of medium-to coarse-grained euhedral pyrite from the stratiform and skarn ore bodies, and pyritization marble are investigated in the Dongguashan deposit. The results of the studied pyrite samples have relatively consistent trace element composition characteristics and several genetically significant elemental combinations. Gold and Ag are mainly of lattice bound appearance in pyrite. The Pb, Cu, Sb and Tl elements are mainly incorporated into the pyrite structure as substitutions. The distinctly trace element distribution correlations (e.g., Mn, Se and Tl) of the studied pyrites indicate that they were formed in a high temperature and oxidizing environment. Low Au (1) and Se/Tl (>10) ratios of the studied pyrites imply that the Dongguashan deposit is most likely to be a magmatic-hydrothermal origin.
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- 2020
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13. Geochemistry and genesis of the Nadun Nb-enriched arc basalt in the Duolong mineral district, western Tibet: Indication of ridge subduction
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Tian-Yu Zhang, Jianghong Deng, Ming Wang, Cai Li, Lipeng Zhang, and Weidong Sun
- Subjects
Tibet ,Duolong porphyry Cu–Au deposit ,Nb-enriched arc basalt ,Tethys ocean ,Ridge subduction ,Geology ,QE1-996.5 - Abstract
The Duolong mineral district in western Tibet is one of the largest porphyry Cu–Au deposit fields with significant metallogenic potential in China. Its tectonic environment relevant to Early Cretaceous Cu–Au mineralization remains controversial. Here we report new whole-rock major and trace element, and Sr-Nd-Hf-Pb isotopic data for the newly discovered basalt in the Nadun area, Duolong mineral district, to decipher their genesis and further constrain the tectonic environment. A contemporaneous rhyolite sample interbedded with the basalt in the lower part of the volcanic section in the Nadun area yields an LA-ICP-MS zircon U–Pb age of 122.5 ± 1.2 Ma. The basalt samples exhibit high-K calc-alkaline/shoshonite properties and are enriched in high field strength elements, e.g., high TiO2 (1.43–1.79 wt.%) and Nb (14.6–19.5 ppm) contents, with high Nb/La ratios (0.4–0.6), which are compositionally comparable to those of Nb-enriched arc basalts (NEABs). The (87Sr/86Sr)i ratios of 0.7052 to 0.7056, negative εNd(t) (− 0.7 to − 0.2) and εHf(t) values (+ 6.0 to + 6.5), and high (206Pb/204Pb)i, (207Pb/204Pb)i, (208Pb/204Pb)i and ratios (18.522 to 18.561, 15.641 to 15.645 and 38.679 to 38.730, respectively) suggest that the Nadun NEABs are more enriched than those of the island arc basalts (IABs) in the area. The slightly enriched radiogenic isotopes for the Nadun NEABs indicate that the subducting sediments play an important role in the source. Furthermore, their high Nb, Ti, and Cu contents indicate that the source mantle wedge was metasomatized by slab melts. The Nadun NEAB and other coeval magmatic rocks in the Duolong mineral district, including adakite, OIB-like basalt, MORB-type basalt, A-type rhyolite, and common IAB, are typical rock assemblages of ridge subduction. We infer that the Duolong mineral district were formed by ridge subduction in the Early Cretaceous.
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- 2022
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14. Ore deposits in the Lower Yangtze River Belt
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Weidong Sun
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Geology ,QE1-996.5 - Published
- 2021
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15. 'Yanshanian Movement' induced by the westward subduction of the paleo–Pacific plate
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Zhe-Kun Zhang, Ming-Xing Ling, Wei Lin, Ming Sun, and Weidong Sun
- Subjects
Yanshanian movement ,Subduction ,Paleo–Pacific plate ,North China Craton ,Analogue modelling ,Geology ,QE1-996.5 - Abstract
Mountain building (orogeny) has a strong causal relationship with compression induced by plate drifting. It is generally accepted that orogenic belts are distributed perpendicular to the direction of plate movement. Extensive Late Mesozoic intra-continental deformations occurred around the North China Craton (NCC) in three different directions (i.e. EW-, WNW- and NNE-striking), which were previously attributed to three different geodynamic processes; the closure of the Mongolia-Okhotsk Ocean, convergence of the NCC and the South China block, and subduction of the paleo-Pacific plate. Remarkably, all these tectonic events were synchronised. Analogue modelling experiments were used to constrain far-field stress and basement shapes, to reconsider tectonic evolution around the NCC during this period. Results showed that all of these tectonic deformations could be plausibly interpreted as a unitary geodynamic regime governed by the westward indentation of the wedge-shaped NCC, driven by subduction of the paleo-Pacific plate. Mountain chains were formed along the edges of the wedge, indicating that the distribution of orogenic belts is not necessarily correlated with the direction of plate movement.
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- 2020
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16. The Late Mesozoic granodiorite and polymetallic mineralization in southern Anhui Province, China: A perspective from apatite geochemistry
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Lin Qian, Yu Wang, Jiancheng Xie, and Weidong Sun
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Geology ,QE1-996.5 - Abstract
The region of southern Anhui Province (SAP) is one of Late Mesozoic magmatic belts and copper-molybdenum-gold-tungsten polymetallic ore districts in China, but the relationship of polymetallic mineralization and related granodiorite remains unclear. Previous studies indicate that apatite can be an indicator for magmatic evolution and mineral exploration. In this study, apatites from the SAP ore-bearing granodiorites were investigated using observations from the electron microscope, electron probe microanalysis (EPMA), laser-ablation inductively-coupled plasma-mass spectrometry (LA-ICP-MS). The studied apatite samples identified as fluorapatite, show high F (2.69–4.13 wt.%) and low Cl contents (mainly
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- 2019
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17. Oxidative Dehydrogenation of Ethane: Superior Nb2O5-NiO/Ni-Foam Catalyst Tailored by Tuning Morphology of NiO-Precursors Grown on a Ni-Foam
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Zhiqiang Zhang, Guofeng Zhao, Weidong Sun, Ye Liu, and Yong Lu
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Science - Abstract
Summary: Large-scale shale gas exploitation greatly enriches ethane resources, making the oxidative dehydrogenation of ethane to ethylene quite fascinating, but the qualified catalyst with unique combination of enhanced activity/selectivity, enhanced heat transfer, and low pressure drop presents a grand challenge. Herein, a high-performance Nb2O5-NiO/Ni-foam catalyst engineered from nano- to macroscale for this reaction is tailored by finely tuning the performance-relevant Nb2O5-NiO interaction that is strongly dependent on NiO-precursor morphology. Three NiO-precursors of different morphologies (clump, rod, and nanosheet) were directly grown onto Ni-foam followed by Nb2O5 modification to obtain the catalyst products. Notably, the one from the NiO-precursor of nanosheet achieves the highest ethylene yield, in nature, because of markedly diminished unselective oxygen species due to enhanced interaction between Nb2O5 and NiO nanosheet. An advanced catalyst is developed by further thinning the NiO-precursor nanosheet, which achieves 60% conversion with 80% selectivity and is stable for at least 240 h. : Catalysis; Organic Reaction; Nanomaterials; Nanostructure Subject Areas: Catalysis, Organic Reaction, Nanomaterials, Nanostructure
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- 2019
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18. Geochemistry of subducted metabasites exhumed from the Mariana forearc: Implications for Pacific seamount subduction
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Jianghong Deng, Lipeng Zhang, He Liu, Haiyang Liu, Renqiang Liao, Abdul Shakoor Mastoi, Xiaoyong Yang, and Weidong Sun
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IODP 366 ,Mariana convergent margin ,Forearc ,Seamount subduction ,OIB ,Geology ,QE1-996.5 - Abstract
Seamounts on the drifting oceanic crust are inevitably carried by plate motions and eventually accreted or subducted. However, the geochemical signatures of the subducted seamounts and the significance of seamount subduction are not well constrained. Hundreds of seamounts have subducted beneath the Philippine Sea Plate following the westward subduction of the Pacific Plate since the Eocene (~52 Ma). The subducted oceanic crust and seamount materials can be exhumed from the mantle depth to the seafloor in the Mariana forearc region by serpentinite mud volcanoes, providing exceptional opportunities to directly study the subducted oceanic crust and seamounts. The International Ocean Discovery Program (IODP) expedition 366 has recovered a few metamorphosed mafic clasts exhumed from the Mariana forearc serpentinite mud volcanoes, e.g., the Fantangisña and Asùt Tesoru seamounts. These mafic clasts have tholeiitic to alkaline affinities with distinct trace elements and Nd-Hf isotopes characteristics, suggesting different provenances and mantle sources. The tholeiites from the Fantangisña Seamount have trace element characteristics typical of mid-ocean ridge basalt. The Pacific-type Hf-Nd isotopic compositions, combined with the greenschist metamorphism of these tholeiites further suggest that they came from the subducted Pacific oceanic crust. The alkali basalts-dolerites from the Fantangisña and Asùt Tesoru seamounts show ocean island basalt (OIB)-like geochemical characteristics. The OIB-like geochemical signatures and the low-grade metamorphism of these alkali basalts-dolerites suggest they came from subducted seamounts that originally formed in an intraplate setting on the Pacific Plate. The Pacific Plate origin of these metabasites suggests they were formed in the Early Cretaceous or earlier.Two types of OIBs have been recognized from alkali metabasites, one of which is geochemically similar to the HIMU-EMI-type OIBs from the West Pacific Seamount Province, and another is similar to the EMII-type OIBs from the Samoa Island in southern Pacific, with negative Nb-Ta-Ti anomalies and enriched Nd-Hf isotopes. Generally, these alkali metabasites are sourced from the heterogeneous mantle sources that are similar to the present South Pacific Isotopic and Thermal Anomaly. This study provides direct evidence for seamount subduction in the Mariana convergent margins. We suggest seamount subduction is significant to element cycling, mantle heterogeneity, and mantle oxidation in subduction zones.
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- 2021
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19. Corrigendum to 'Yanshanian movementˮ induced by the westward subduction of the paleo–Pacific plate [Solid Earth Sciences Volume 5 (2) (2020) 103–114]
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Zhe-Kun Zhang, Ming-Xing Ling, Wei Lin, Ming Sun, and Weidong Sun
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Geology ,QE1-996.5 - Published
- 2021
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20. Identification of Frataxin as a regulator of ferroptosis
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Jing Du, Yi Zhou, Yanchun Li, Jun Xia, Yongjian Chen, Sufeng Chen, Xin Wang, Weidong Sun, Tongtong Wang, Xueying Ren, Xu Wang, Yihan An, Kang Lu, Wanye Hu, Siyuan Huang, Jianghui Li, Xiangmin Tong, and Ying Wang
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Ferroptosis ,Frataxin ,Iron-sulfur cluster ,Mitochondria ,Medicine (General) ,R5-920 ,Biology (General) ,QH301-705.5 - Abstract
Ferroptosis is a newly discovered form of non-apoptotic regulated cell death and is characterized by iron-dependent and lipid peroxidation. Due to the enhanced dependence on iron in cancer cells, induction of ferroptosis is becoming a promising therapeutic strategy. However, the precise underlying molecular mechanism and regulation process of ferroptosis remains largely unknown. In the present study, we demonstrate that the protein Frataxin (FXN) is a key regulator of ferroptosis by modulating iron homeostasis and mitochondrial function. Suppression of FXN expression specifically repressed the proliferation, destroyed mitochondrial morphology, impeded Fe–S cluster assembly and activated iron starvation stress. Moreover, suppression of FXN expression significantly enhanced erastin-induced cell death through accelerating free iron accumulation, lipid peroxidation and resulted in dramatic mitochondria morphological damage including enhanced fragmentation and vanished cristae. In addition, this type of cell death was confirmed to be ferroptosis, since it could be pharmacologically restored by ferroptotic inhibitor Fer-1 or GSH, but not by inhibitors of apoptosis, necrosis. Vice versa, enforced expression of FXN blocked iron starvation response and erastin-induced ferroptosis. More importantly, pharmacological or genetic blocking the signal of iron starvation could completely restore the resistance to ferroptosis in FXN knockdown cells and xenograft graft in vivo. This paper suggests that FXN is a novel ferroptosis modulator, as well as a potential provided target to improve the antitumor activity based on ferroptosis.
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- 2020
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21. The production of iron oxide during peridotite serpentinization: Influence of pyroxene
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Ruifang Huang, Chiou-Ting Lin, Weidong Sun, Xing Ding, Wenhuan Zhan, and Jihao Zhu
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Serpentinization ,Iron oxide ,Peridotite ,Orthopyroxene ,Silica ,Aluminum ,Geology ,QE1-996.5 - Abstract
Serpentinization produces molecular hydrogen (H2) that can support communities of microorganisms in hydrothermal fields; H2 results from the oxidation of ferrous iron in olivine and pyroxene into ferric iron, and consequently iron oxide (magnetite or hematite) forms. However, the mechanisms that control H2 and iron oxide formation are poorly constrained. In this study, we performed serpentinization experiments at 311 °C and 3.0 kbar on olivine (with
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- 2017
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22. The age of the Ordovician-Silurian boundary and the End Ordovician Mass Extinction
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Weidong Sun
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Geology ,QE1-996.5 - Published
- 2020
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23. Challenges in Solid Earth Sciences
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Weidong Sun
- Subjects
Geology ,QE1-996.5 - Published
- 2016
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24. The initiation of plate subduction
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Weidong Sun
- Subjects
Geology ,QE1-996.5 - Published
- 2017
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25. The geomicrobiology of bauxite deposits
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Xiluo Hao, Kwunlun Leung, Rucheng Wang, Weidong Sun, and Yiliang Li
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Geomicrobiology ,Bauxite ,Microbial activity ,Microbial-mediated release of elements ,Biomineralization ,Geology ,QE1-996.5 - Abstract
Bauxite deposits are studied because of their economic value and because they play an important role in the study of paleoclimate and paleogeography of continents. They provide a rare record of the weathering and evolution of continental surfaces. Geomicrobiological analysis makes it possible to verify that microorganisms have played a critical role during the formation of bauxite with the possibility already intimated in previous studies. Ambient temperature, abundance of water, organic carbon and bioavailable iron and other metal substrates provide a suitable environment for microbes to inhabit. Thiobacillus, Leptospirilum, Thermophilic bacteria and Heterotrophs have been shown to be able to oxidize ferrous iron and to reduce sulfate-generating sulfuric acid, which can accelerate the weathering of aluminosilicates and precipitation of iron oxyhydroxides. Microorganisms referred to the genus Bacillus can mediate the release of alkaline metals. Although the dissimilatory iron-reducing and sulfate-reducing bacteria in bauxites have not yet been identified, some recorded authigenic carbonates and “bacteriopyrites” that appear to be unique in morphology and grain size might record microbial activity. Typical bauxite minerals such as gibbsite, kaolinite, covellite, galena, pyrite, zircon, calcium plagioclase, orthoclase, and albite have been investigated as part of an analysis of microbial mediation. The paleoecology of such bauxitic microorganisms inhabiting continental (sub) surfaces, revealed through geomicrobiological analysis, will add a further dimension to paleoclimatic and paleoenvironmental studies.
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- 2010
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26. Water in coesite: Incorporation mechanism and operation condition, solubility and P-T dependence, and contribution to water transport and coesite preservation
- Author
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Weidong Sun, Lifei Zhang, Wei Yan, Yunlu Ma, Christina Yan Wang, Mingyue He, Yanyao Zhang, and Xi Liu
- Subjects
010504 meteorology & atmospheric sciences ,Hydrogen ,Coesite preservation ,Analytical chemistry ,chemistry.chemical_element ,Electron microprobe ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,Phase (matter) ,Coesite ,Solubility ,0105 earth and related environmental sciences ,Water transport ,Mineral ,Aqueous solution ,Anhydrous minerals ,lcsh:QE1-996.5 ,New IR experimental Protocol ,P-T dependence of water solubility ,lcsh:Geology ,Water-incorporation mechanism ,chemistry ,FTIR ,engineering ,General Earth and Planetary Sciences - Abstract
A series of coesite, coexisting with or without a liquid phase, was synthesized in the nominal system SiO2–H2O at 800–1450 °C and 5 GPa. Micro-Raman spectroscopy was used to identify the crystalline phase, electron microprobe and LA-ICP-MS were employed to quantify some major and trace elements, and unpolarized FTIR spectroscopy was applied to probe the different types of hydrogen defects, explore water-incorporation mechanisms and quantify water contents. Trace amounts of Al and B were detected in the coesite. Combining our results with the results in the literatures, we have found no positive correlation between the Al contents and the “Al”-based hydrogen concentrations, suggesting that previously proposed hydrogen-incorporation mechanism H+ + Al3+ ↔ Si4+ does not function in coesite. In contrast, we have confirmed the positive correlation between the B contents and the B-based hydrogen concentrations. The hydrogen-incorporation mechanism H+ + B3+ ↔ Si4+ readily takes place in coesite at different P-T conditions, and significantly increases the water content at both liquid-saturated and liquid-undersaturated conditions. For the SiO2–H2O system, we have found that type-I hydrogarnet substitution plays a dictating role in incorporating water into coesite at liquid-saturated condition, type-II hydrogarnet substitution contributes significantly at nearly dry condition, and both operate at conditions in between. The water solubility of coesite, as dictated by the type-I hydrogarnet substitution, positively correlates with both P and T, c H 2 O = −105(30) + 5.2(32) × P + 0.112(26) × T, with c H 2 O in wt ppm, P in GPa and T in °C. Due to its low water solubility and small fraction in subducted slabs, coesite may contribute insignificantly to the vertical water transport in subduction zones. Furthermore, the water solubility of any coesite in exhuming ultra-high pressure metamorphic rocks should be virtually zero as coesite becomes metastable. With an adequately fast water-diffusion rate, this metastable coesite should be completely dry, which may have been the key factor to the partial preservation of most natural Coe. As a byproduct, a new IR experimental protocol for accurate water determination in optically anisotropic nominally anhydrous minerals has been found. Aided with the empirical method of Paterson (1982) it employs multiple unpolarized IR spectra, collected from randomly-orientated mineral grains, to approximate both total integrated absorbance and total integrated molar absorption coefficient. Its success relies on a high-level orientation randomness in the IR analyses.
- Published
- 2021
27. Geochemistry and genesis of the Nadun Nb-enriched arc basalt in the Duolong mineral district, western Tibet: Indication of ridge subduction
- Author
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Cai Li, Ming Wang, Jianghong Deng, Tian-Yu Zhang, Weidong Sun, and Lipeng Zhang
- Subjects
Basalt ,QE1-996.5 ,Mantle wedge ,Subduction ,Geochemistry ,Trace element ,Nb-enriched arc basalt ,Ridge subduction ,Geology ,Tethys ocean ,Tibet ,Rhyolite ,Adakite ,General Earth and Planetary Sciences ,Island arc ,Duolong porphyry Cu–Au deposit ,Zircon - Abstract
The Duolong mineral district in western Tibet is one of the largest porphyry Cu–Au deposit fields with significant metallogenic potential in China. Its tectonic environment relevant to Early Cretaceous Cu–Au mineralization remains controversial. Here we report new whole-rock major and trace element, and Sr-Nd-Hf-Pb isotopic data for the newly discovered basalt in the Nadun area, Duolong mineral district, to decipher their genesis and further constrain the tectonic environment. A contemporaneous rhyolite sample interbedded with the basalt in the lower part of the volcanic section in the Nadun area yields an LA-ICP-MS zircon U–Pb age of 122.5 ± 1.2 Ma. The basalt samples exhibit high-K calc-alkaline/shoshonite properties and are enriched in high field strength elements, e.g., high TiO2 (1.43–1.79 wt.%) and Nb (14.6–19.5 ppm) contents, with high Nb/La ratios (0.4–0.6), which are compositionally comparable to those of Nb-enriched arc basalts (NEABs). The (87Sr/86Sr)i ratios of 0.7052 to 0.7056, negative eNd(t) (− 0.7 to − 0.2) and eHf(t) values (+ 6.0 to + 6.5), and high (206Pb/204Pb)i, (207Pb/204Pb)i, (208Pb/204Pb)i and ratios (18.522 to 18.561, 15.641 to 15.645 and 38.679 to 38.730, respectively) suggest that the Nadun NEABs are more enriched than those of the island arc basalts (IABs) in the area. The slightly enriched radiogenic isotopes for the Nadun NEABs indicate that the subducting sediments play an important role in the source. Furthermore, their high Nb, Ti, and Cu contents indicate that the source mantle wedge was metasomatized by slab melts. The Nadun NEAB and other coeval magmatic rocks in the Duolong mineral district, including adakite, OIB-like basalt, MORB-type basalt, A-type rhyolite, and common IAB, are typical rock assemblages of ridge subduction. We infer that the Duolong mineral district were formed by ridge subduction in the Early Cretaceous.
- Published
- 2022
28. The Late Mesozoic granodiorite and polymetallic mineralization in southern Anhui Province, China: A perspective from apatite geochemistry
- Author
-
Weidong Sun, Yu Wang, Jiancheng Xie, and Lin Qian
- Subjects
Mineralization (geology) ,Electron probe microanalysis ,010504 meteorology & atmospheric sciences ,Fluorapatite ,lcsh:QE1-996.5 ,Geochemistry ,Geology ,Electron microprobe ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Apatite ,lcsh:Geology ,Mineral exploration ,Geophysics ,Geochemistry and Petrology ,visual_art ,visual_art.visual_art_medium ,Mesozoic ,0105 earth and related environmental sciences ,Earth-Surface Processes - Abstract
The region of southern Anhui Province (SAP) is one of Late Mesozoic magmatic belts and copper-molybdenum-gold-tungsten polymetallic ore districts in China, but the relationship of polymetallic mineralization and related granodiorite remains unclear. Previous studies indicate that apatite can be an indicator for magmatic evolution and mineral exploration. In this study, apatites from the SAP ore-bearing granodiorites were investigated using observations from the electron microscope, electron probe microanalysis (EPMA), laser-ablation inductively-coupled plasma-mass spectrometry (LA-ICP-MS). The studied apatite samples identified as fluorapatite, show high F (2.69–4.13 wt.%) and low Cl contents (mainly
- Published
- 2019
29. Geochemistry of subducted metabasites exhumed from the Mariana forearc: Implications for Pacific seamount subduction
- Author
-
Lipeng Zhang, Xiaoyong Yang, Abdul Shakoor Mastoi, Haiyang Liu, Renqiang Liao, Weidong Sun, He Liu, and Jianghong Deng
- Subjects
Basalt ,geography ,geography.geographical_feature_category ,Subduction ,Pacific Plate ,Seamount ,lcsh:QE1-996.5 ,Geochemistry ,Ocean island basalt ,Forearc ,Seafloor spreading ,Seamount subduction ,lcsh:Geology ,Oceanic crust ,Mariana convergent margin ,General Earth and Planetary Sciences ,OIB ,IODP 366 ,Geology - Abstract
Seamounts on the drifting oceanic crust are inevitably carried by plate motions and eventually accreted or subducted. However, the geochemical signatures of the subducted seamounts and the significance of seamount subduction are not well constrained. Hundreds of seamounts have subducted beneath the Philippine Sea Plate following the westward subduction of the Pacific Plate since the Eocene (~52 Ma). The subducted oceanic crust and seamount materials can be exhumed from the mantle depth to the seafloor in the Mariana forearc region by serpentinite mud volcanoes, providing exceptional opportunities to directly study the subducted oceanic crust and seamounts. The International Ocean Discovery Program (IODP) expedition 366 has recovered a few metamorphosed mafic clasts exhumed from the Mariana forearc serpentinite mud volcanoes, e.g., the Fantangisna and Asut Tesoru seamounts. These mafic clasts have tholeiitic to alkaline affinities with distinct trace elements and Nd-Hf isotopes characteristics, suggesting different provenances and mantle sources. The tholeiites from the Fantangisna Seamount have trace element characteristics typical of mid-ocean ridge basalt. The Pacific-type Hf-Nd isotopic compositions, combined with the greenschist metamorphism of these tholeiites further suggest that they came from the subducted Pacific oceanic crust. The alkali basalts-dolerites from the Fantangisna and Asut Tesoru seamounts show ocean island basalt (OIB)-like geochemical characteristics. The OIB-like geochemical signatures and the low-grade metamorphism of these alkali basalts-dolerites suggest they came from subducted seamounts that originally formed in an intraplate setting on the Pacific Plate. The Pacific Plate origin of these metabasites suggests they were formed in the Early Cretaceous or earlier. Two types of OIBs have been recognized from alkali metabasites, one of which is geochemically similar to the HIMU-EMI-type OIBs from the West Pacific Seamount Province, and another is similar to the EMII-type OIBs from the Samoa Island in southern Pacific, with negative Nb-Ta-Ti anomalies and enriched Nd-Hf isotopes. Generally, these alkali metabasites are sourced from the heterogeneous mantle sources that are similar to the present South Pacific Isotopic and Thermal Anomaly. This study provides direct evidence for seamount subduction in the Mariana convergent margins. We suggest seamount subduction is significant to element cycling, mantle heterogeneity, and mantle oxidation in subduction zones.
- Published
- 2021
30. Corrigendum to 'Yanshanian movementˮ induced by the westward subduction of the paleo–Pacific plate [Solid Earth Sciences Volume 5 (2) (2020) 103–114]
- Author
-
Ming Sun, Wei Lin, Zhe-Kun Zhang, Ming-Xing Ling, and Weidong Sun
- Subjects
lcsh:Geology ,Geophysics ,Volume (thermodynamics) ,Subduction ,Geochemistry and Petrology ,Pacific Plate ,lcsh:QE1-996.5 ,Geology ,Geotechnical Engineering and Engineering Geology ,Petrology ,Solid earth ,Earth-Surface Processes - Published
- 2021
31. Soil moisture retrieval over agricultural fields from L-band multi-incidence and multitemporal PolSAR observations using polarimetric decomposition techniques
- Author
-
Weidong Sun, Lei Shi, Hongtao Shi, Juan M. Lopez-Sanchez, Lingli Zhao, Jinqi Zhao, Pingxiang Li, Jie Yang, Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante. Instituto Universitario de Investigación Informática, and Señales, Sistemas y Telecomunicación
- Subjects
L band ,010504 meteorology & atmospheric sciences ,0208 environmental biotechnology ,Soil Science ,Synthetic aperture radar ,02 engineering and technology ,Polarimetric decomposition ,01 natural sciences ,Natural science ,Computers in Earth Sciences ,Water content ,0105 earth and related environmental sciences ,Remote sensing ,business.industry ,Multi-incidence ,Foundation (engineering) ,Geology ,020801 environmental engineering ,Work (electrical) ,State agency ,Agriculture ,Teoría de la Señal y Comunicaciones ,Environmental science ,Multitemporal ,Soil moisture ,business - Abstract
Surface soil moisture (SM) retrieval over agricultural areas from polarimetric synthetic aperture radar (PolSAR) has long been restricted by vegetation attenuation, simplified polarimetric scattering modelling, and limited SAR measurements. This study proposes a modified polarimetric decomposition framework to retrieve SM from multi-incidence and multitemporal PolSAR observations. The framework is constructed by combining the X-Bragg model, the extended double Fresnel scattering model and the generalised volume scattering model (GVSM). Compared with traditional decomposition models, the proposed framework considers the depolarisation of dihedral scattering and the diverse vegetation contribution. Under the assumption that SM is invariant for the PolSAR observations at two different incidence angles and that vegetation scattering does not change between two consecutive measurements, analytical parameter solutions, including the dielectric constant of soil and crop stem, can be obtained by solving multivariable nonlinear equations. The proposed framework is applied to the time series of L-band uninhabited aerial vehicle synthetic aperture radar data acquired during the Soil Moisture Active Passive Validation Experiment in 2012. In this study, we assess retrieval performance by comparing the inversion results with in-situ measurements over bean, canola, corn, soybean, wheat and winter wheat areas and comparing the different performance of SM retrieval between the GVSM and Yamaguchi volume scattering models. Given that SM estimation is inherently influenced by crop phenology and empirical parameters which are introduced in the scattering models, we also investigate the influence of surface depolarisation angle and co-pol phase difference on SM estimation. Results show that the proposed retrieval framework provides an inversion accuracy of RMSE
- Published
- 2021
32. Post-ridge-subduction acceleration of the Indian plate induced by slab rollback
- Author
-
He Li, Jiqiang Liu, Yong bing Hu, Weidong Sun, Wei Ding, Xing Ding, Lijun Liu, Zhaofeng Zhang, Xin-lei Sun, Ming-Xing Ling, Wei ming Fan, and Congying Li
- Subjects
Slab rollback ,010504 meteorology & atmospheric sciences ,Slab pull ,Ridge subduction ,010502 geochemistry & geophysics ,Tibet ,01 natural sciences ,Mantle plume ,Adakite ,Geochemistry and Petrology ,Asthenosphere ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Subduction ,lcsh:QE1-996.5 ,Geology ,Geotechnical Engineering and Engineering Geology ,lcsh:Geology ,Plate tectonics ,Geophysics ,Ridge push ,Slab ,Driving force ,Seismology - Abstract
The driving forces of plate motion, especially that of its sudden change over time, has long been debated. During the closure of an old ocean, the subduction process of the mid-ocean ridge provides valuable clues to quantitative evaluation of the driving forces of plate tectonics. Here we show that the drifting rates of the Indian plate were correlated with a Late Cretaceous adakitic event hosting abundant adakites and adakitic charnockites in the Gangdese belt, southern Tibetan Plateau. While adakites form through slab melting, the ultra-high temperatures and dry nature of charnockites indicate major disturbance of the hot asthenosphere. Temporally, the oldest adakite corresponds to the initiation of the ridge subduction, whereas the youngest adakitic charnockite marks the onset of post-ridge-subduction slab rollback (steepening). Geodynamic modeling suggests that the initiation of the ridge subduction was facilitated by the Morondova mantle plume, corresponding to the lowest drifting rate of the Indian plate. Our analyses further show that the post-ridge-subduction slab rollback pushed the asthenospheric mantle backward, meanwhile it dramatically reduced the ridge-arc interaction force, leading to the first abrupt acceleration of the Indian plate. Slab rollback contributed ∼3.5 cm/yr but lasted for only ∼5 Ma, while slab pull, ridge push together with plume contributed ∼5 cm/yr to the acceleration of the Indian plate. Our study, therefore, provides evidence for a new type of driving forces of Indian plate acceleration during the Late Cretaceous Neotethys ridge subduction.
- Published
- 2018
33. Carbon recycling through alkali basalts
- Author
-
Weidong Sun and Chan-chan Zhang
- Subjects
Basalt ,010504 meteorology & atmospheric sciences ,lcsh:QE1-996.5 ,Geochemistry ,chemistry.chemical_element ,Geology ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,Alkali metal ,01 natural sciences ,lcsh:Geology ,Geophysics ,chemistry ,Geochemistry and Petrology ,Carbon ,0105 earth and related environmental sciences ,Earth-Surface Processes - Published
- 2017
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