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Formation and evolution of supercritical geofluid

Science China Earth Sciences 2025年第1期68卷 39-51页

作者： Huaiwei NI yilin XIAO Xiaolin XIONG Xiandong LIU Chunxiao GAO yi-xiang chen Yunguo LI Wan-Cai LI Xuan GUO Yang-Yang WANG Dong-Bo TAN Li ZHANG State Key Laboratory of Lithospheric and Environmental Coevolution University of Science and Technology of China Deep Space Exploration Laboratory/School of Earth and Space Sciences University of Science and Technology of China Guangzhou Institute of Geochemistry Chinese Academy of Sciences School of Earth Sciences and Engineering Nanjing University State Key Lab of Superhard Materials Jilin University

In this work, we provide a comprehensive review on the formation, evolution, properties, and effects of supercritical geofluid. In Earth's interior, enhanced miscibility between H2O and silicate by the addition of special components or by the increase of pressure and temperature gives rise to supercritical geofluid with a significant amount of both H2O and silicate *** formation of supercritical geofluid in magmatic-hydrothermal systems, typified by pegmatite system, is governed by meltfluid critical curve. The formation of supercritical geofluid in metamorphic systems, typified by subducted slab, is governed by the second critical end point. Experimental results suggest that the presence of boron and fluorine in pegmatite system makes it possible to form supercritical geofluid at crustal depths, but the release of supercritical geofluid from subducted slab is withheld until almost 100 km depth. A major presence of both H2O and depolymerized structural units（monomers, dimers, etc.） endows supercritical geofluid with unique physical properties including low density, low elastic moduli, low viscosity, high diffusivity,and high electrical conductivity. Supercritical geofluid can effectively mobilize a variety of elements even including high field strength elements and heavy rare earth elements. The chemical signatures of supercritical geofluid can be inherited by metasomatized mantle and mantle-derived melts, and this could give an explanation of the oxidation of arc magmas. Phase separation of supercritical geofluid through the mechanism of spinodal decomposition leads to formation of a melt network. Multiphase fluid inclusions recovered from subduction zone rocks and pegmatites are possible relics of supercritical geofluid. Supercritical geofluid can cause electrical anomaly and low seismic velocity near the top of subducted slab, and can be linked with intermediate-focus earthquakes. Supercritical geofluid may have played a crucial role in the formation of pe

关键词： Supercritical geofluid Miscibility Subduction zone Pegmatite

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Continental versus oceanic subduction zones

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National Science Review 2016年第4期3卷 495-519页

作者： Yong-Fei Zheng yi-xiang chen CAS Key Laboratory of Crust-mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of China

Subduction zones are tectonic expressions of convergent plate margins,where crustal rocks descend into and interact with the overlying mantle *** are the geodynamic system that produces maic arc volcanics above oceanic subduction zones but high-to ultrahigh-pressure metamorphic rocks in continental subduction *** the metamorphic rocks provide petrological records of orogenic processes when descending crustal rocks undergo dehydration and anataxis at forearc to subarc depths beneath the mantle wedge,the arc volcanics provide geochemical records of the mass transfer from the subducting slab to the mantle wedge in this period though the mantle wedge becomes partially melted at a later *** the mantle wedge overlying the subducting oceanic slab is of asthenospheric origin,that overlying the descending continental slab is of lithospheric origin,being ancient beneath cratons but juvenile beneath marginal *** either case,the mantle wedge base is cooled down during the slab–wedge coupled *** dehydration is prominent during subduction of crustal rocks,giving rise to aqueous solutions that are enriched in luid-mobile incompatible *** the subducting slab is decoupled from the mantle wedge,the slab–mantle interface is heated by lateral incursion of the asthenospheric mantle to allow dehydration melting of rocks in the descending slab surface and the metasomatized mantle wedge base,***,the tectonic regime of subduction zones changes in both time and space with respect to their structures,inputs,processes and *** record the tectonic conversion from sealoor spreading to oceanic subduction beneath continental margin,whereas ultrahigh-temperature metamorphic events mark the tectonic conversion from compression to extension in orogens.

关键词： subduction factory orogenic magmatism ophiolite UHP metamorphism UHT metamorphism

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First finding of continental deep subduction in the Sesia Zone of the Western Alps and implications for subduction dynamics

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National Science Review 2023年第5期10卷 154-166页

作者： yi-xiang chen Kun Zhou Qiang He Yong-Fei Zheng Hans-Peter Schertl Kun chen CAS Key Laboratory of Crust-Mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of China Center of Excellence for Comparative Planetology Chinese Academy of Sciences Institute of Geology Mineralogy and Geophysics Faculty of GeosciencesRuhr University Bochum

Continental deep subduction after the closure of large oceanic basins is commonly ascribed to the gravitational pull of the subducting oceanic ***,it is not clear how continental lithosphere adjacent to small oceanic basins was subducted to mantle *** Sesia Zone in the Western Alps provides an excellent target for exploration of subduction dynamics in such a tectonic *** we report the first finding of coesite in a jadeite-bearing orthogneiss from the Sesia Zone,providing the first evidence for deep subduction of the continental crust to mantle depths for ultrahigh-pressure(UHP)metamorphism in this *** coesite inclusions were identified by laser Raman spectroscopy in two garnet *** on zircon U-Pb dating and trace element analysis, the UHP metamorphic age was constrained to be 76.0 ±1.0 *** phase equilibrium modeling yields peak metamorphic pressures of2.8-3.3 GPa,demonstrating the continental deep subduction to mantle depths of>80 *** subducted continental crust was a rifted hyperextended continental margin,which was converted to the passive continental margin during seafloor spreading and then deeply subducted during the oblique convergence between the Adria microplate and Eurasian plate in the Late *** the slab pull could only play a limited role in closing small oceanic basins for continental collision,the distal push of either continental breakup or seafloor spreading is suggested as the major driving force for the deep subduction of continental crust in the Western ***,deep subduction of the continental crust bordering small oceanic basins would have been induced by the far-field stress of compression,whereas that bordering large oceanic basins was spontaneous due to the oceanic slab *** provides a new insight into the geodynamic me chanism of continental deep subduction.

关键词： coesite ultrahigh-pressure metamorphism continental deep subduction Western Alps far-field stress

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Extreme geochemical fractionation during mantle melting:Insights from Hf-Nd isotopically ultra-depleted eclogite

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Geoscience Frontiers 2024年第6期15卷 156-166页

作者： Kun Zhou yi-xiang chen Yong-Fei Zheng Ren-Xu chen Yueheng Yang School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Lithospheric and Environmental Co-evolution University of Science and Technology of ChinaHefei 230026China Center of Excellence for Comparative Planetology Chinese Academy of SciencesHefei 230026China State Key Laboratory of Lithospheric and Environmental Co-evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

Extreme fractionation of elements and isotopes in mafic igneous rocks is abnormal in deciphering the source nature and melting conditions of mafic ***,identification of geochemically ultra-depleted mafic melts and their mantle sources has great bearing on the property of crust-mantle differentiation at plate *** is illustrated by extreme Hf-Nd isotope fractionation in ultrahigh-pressure eclogites from the Sulu orogen in east-central *** addition to the previous finding of ultrahighεNd(0)values,we report here new data of whole-rock trace elements and Lu-Hf isotopes in eclogites and related rocks from the same *** present results show extremely high Lu/Hf ratios and abnormally highεHf(0)values of up to 576 for the eclogites,significantly different from the garnet amphibolites and other eclogite-facies metamorphic rocks in the same *** feature is coupled with the ultrahighεNd(0)values as well as the severe depletion of light rare earth elements(LREE)and high field strength elements(HFSE).Because HFSE and LREE are immobile in aqueous solutions and the effect of melt extraction is insignificant during the continental deep subduction,the extreme fractionation of Lu/Hf and Sm/Nd indicate their origination from a geochemically ultra-depleted mantle *** eclogites have the depleted mantle Hf model ages of 1.27 Ga to 1.61 Ga,similar to the depleted mantle Nd model ages of 1.39 Ga to 1.67 Ga as previously *** suggests that the protolith of the extremely highεHf-εNd eclogites was a kind of mafic igneous rocks derived from fractional crystallization of geochemically ultra-depleted mafic melts,which were produced by partial melting of the highly refractory lithospheric mantle during a series of seafloor spreading initiation-failure cycles at a divergent plate margin after the breakup of supercontinent Columbia in the Early *** mafic igneous rocks were located in a passive continental margin in the Lat

关键词： Mantle melting Element fractionation Sub-ridge mantle Spreading initiation Ultra-depleted melt

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Improved anticorrosion performance of mixed valence Mnmodified ZnO dilute magnetic solid solution with multilevel selfassembled network structure

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Nano Research 2022年第7期15卷 6590-6600页

作者： yi-xiang chen Dan Zhou Xiao-Jiao Guo Xiu Yang Si-Rui Zhao yi Lu Jin-Ku Liu Key Laboratory for Advanced Materials School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China Material Corrosion and Protection Key Laboratory of Sichuan ProvinceZigong 643000China

The design and performance prediction of efficient anticorrosion materials is a work full of value,novelty,and *** this work,from the perspective of nanostructure and composition,ZnO-based dilute magnetic solid solution(DMSs)with hydrophobic micronano network structure was synthesized through the self-induced effect of raw materials,the impact-resistant network structure,complex micro-channels,and densely nested layers resisted electrolyte ***,the doping of mixed valence Mn element endowed the solid solution with dilute magnetic properties,so the Lorentz force from micromagnetic field changed the movement path of electrons produced by the anode reaction to improve the corrosion inhibition ability of the protective *** the synergy of morphology and magnetism,the corrosion resistance of the DMSs materials was 555.4%and 173.8%higher than that of epoxy resin and ZnO shielding layer,***,a valuable phenomenon was found that the photocatalytic property of DMSs materials was positively correlated with their corrosive *** conclusion,this research provided a novel design idea for new high-efficiency anticorrosion materials.

关键词： Mn-modified ZnO dilute magnetic solid solution network nanostructure anticorrosion functional nanomaterials

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Fluid effect on zircon O and U-Pb isotopes during ultrahigh-pressure metamorphism:Insights from the Dora-Maira Massif of the Western Alps

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Geoscience Frontiers 2023年第6期14卷 210-223页

作者： Kun Zhou yi-xiang chen Jia-Wei Xiong Hans-Peter Schertl Xiao-Ping Xia CAS Key Laboratory of Crust-Mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei 230026China Institute of Geology Mineralogy and GeophysicsFaculty of GeosciencesRuhr University Bochum44780 BochumGermany College of Earth Science and Engineering Shandong University of Science and TechnologyQingdao 266590China State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

Zircon geochemistry such as U-Pb and O isotopes have been widely used in dating and tracing complex geological ***,it still remains unclear how fluid action affects zircon geochemistry during metamorphic and metasomatic processes in subduction *** a systematic study on zircon U-Pb dating,O isotopes and trace elements as well as whole-rock O isotopes was carried out for the coesite-bearing whiteschists,jadeite quartzites and granitic gneisses from the Dora-Maira Massif,Western ***-rock and zircon geochemistry supports a common protolith,i.e.,Permian S-type granites,for the above three types of rocks and an intense fluid metasomatism during the Alpine orogeny to form whiteschists and jadeite *** cores in all samples have nearly identicalδ^(18)O values(9‰–11‰),whereas their apparent^(206)Pb/^(238)U ages show a greater variability due to Pb loss during *** rims formed in the late Eocene to early Oligocene can be categorized into two ***-Ⅰrims occur in granitic gneisses and jadeite *** have highδ^(18)O values consistent with zircon cores,but much lower contents of P and Y as well as lower Th/U ratios than the *** growth can be attributed to internal metamorphic fluid action at the UHP metamorphic ***-II rims occur in whiteschists and jadeite *** have remarkably lowerδ^(18)O values(5‰–8‰)and Th/U ratios(<0.01),compared with zircon cores and Type-Ⅰ*** growth can be ascribed to external fluids during the metasomatic *** zircon domains in whiteschists and jadeite quartzites show a positive correlation betweenδ^(18)O values and apparent^(206)Pb/^(238)U ages,which suggest the simultaneous impacts on U-Pb-O isotopes during external fluid *** process can be attributed to the fluidassisted dissolution and recrystallization of protolith ***,coesite inclusions that would have been expected to occur only in young zircon rims formed duri

关键词： Subduction zone Fluid action Metasomatism Zircon O isotope U-Pb dating

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A Note on Chromatic Uniqueness of Completely Tripartite Graphs

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Journal of Mathematical Research and Exposition 2010年第2期30卷 233-240页

作者： Ke yi SU xiang En chen College of Mathematics and Information Science Northwest Normal University Gansu 730070 P. R. China

Let P（G,λ） be the chromatic polynomial of a simple graph G. A graph G is chromatically unique if for any simple graph H, P（H,λ） = P（G,λ） implies that H is isomorphic to G. Many sufficient conditions guaranteeing that some certain complete tripartite graphs are chromatically unique were obtained by many scholars. Especially, in 2003, Zou Hui-wen showed that if n 〉 1/3m2 ＋ 3/1k2 ＋ 3/1mk＋ 1/3m-1/3k＋ 3/2√m2 ＋ k2 ＋ mk, where n,k and m are non-negative integers, then the complete tripartite graph K（n - m,n,n ＋ k） is chromatically unique （or simply χ–unique）. In this paper, we prove that for any non-negative integers n,m and k, where m ≥ 2 and k ≥ 0, if n ≥ 3/1m2 ＋ 3/1k2 ＋ 3/1mk ＋ 3/1m - 3/1k ＋ 43, then the complete tripartite graph K（n - m,n,n ＋ k） is χ–unique, which is an improvement on Zou Hui-wen’s result in the case m ≥ 2 and k ≥ 0. Furthermore, we present a related conjecture.

关键词： complete tripartite graph chromatic polynomial chromatic uniqueness color partition.

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SNR WALL AND COOPERATIVE SPECTRUM SENSING IN COGNITIVE RADIO UNDER NOISE UNCERTAINTY

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Journal of Electronics(China) 2010年第5期27卷 611-617页

作者： Wang Haijun Su Xin Xu yi chen xiang Wang Jing Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing 100084China

Cooperative energy spectrum sensing has been proved effective to detect the spectrum holes in Cognitive Radio(CR).However,its performance may suffer from the noise uncertainty,which is portrayed by the SNR wall in some *** this paper we analyze the spectrum sensing per-formance under noise uncertainty and find an alternative approach to obtain the SNR *** the average SNR wall is proposed to illustrate the statistically average impact of noise *** addition,the cooperative sensing performance under noise uncertainty with AND rule is *** and numerical results show that cooperative sensing can significantly improve the sensing performance under the condition of noise uncertainty.

关键词： Cooperative spectrum sensing Noise uncertainty SNR wall

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Vision loss as the initial presentation during primary pulmonary hypertension treatment

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International Journal of Ophthalmology(English edition) 2021年第9期14卷 1460-1462页

作者： Hai-Jiang Zhang Rong Huang Liang Liang Fei Zhou Ping Wu xiang-yi chen The First College of Clinical Medical Science China Three Gorges UniversityYichang 443002Hubei ProvinceChina Institute of Ophthalmology and Visual Science China Three Gorges UniversityYichang 443002Hubei ProvinceChina Department of Ophthalmology Yichang Central People’s HospitalYichang 443003Hubei ProvinceChina Department of Cardiology Yichang Central People’s HospitalYichang 443003Hubei ProvinceChina

Dear Editor,As we all know,pulmonary hypertension is a state of persistent pulmonary artery pressure above 25 mm Hg at rest and greater than 30 mm Hg during *** on the mechanism or underlying etiology,pulmonary hypertension was classified as primary with no identifiable cause or secondary because of increased pressure in the pulmonary venous or pulmonary capillary system[1].

关键词： hypertension pulmonary treatment

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Protective effect of rhubarb on barrier of intestinal mucosa

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World Journal of Gastroenterology 1997年第2期3卷 24-26页

作者： chen De Chang, YANG Xin yi, ZHANG xiang Yu and chen Xie Yun

AIM To investigate the mechanism of the rhubarb on gut barrier protection. METHODS The models of gut barrier damage caused by hemorrhagic shock and intraperitoneal endotoxin were used to study the protective effect of rhubarb on the barrier of intestinal mucosa. They were randomly divided into four groups: treatment (rhubarb) group; positive control group; negative control group; placebo treatment group. The concentration of plasma endotoxin, tissue superoxide dismutase and lipoperoxide were measured. The histological analysis was also used. The effect of rhubarb on gut protection was observed. RESULTS The rhubarb could decrease intestinal permeability, attenuate endotoxin absorption within the gut, (the content of endotoxin in serum: shock group 0 557EU/ml±0 069EU/ml vs rhubarb group 0 345EU/ml±0 055EU/ml), obviously decrease the consumption of tissue SOD and the formation of tissue LPO (the content of SOD in serum, intestine and liver: endotoxin group 122 92NU/ml±43 19NU/ml, 292 24NU/ml±88 76NU/ml, 272 70NU/ml±85 79NU/ml vs rhubarb group 312 23NU/ml±54 93NU/ml, 391 09NU/mg±98 16NU/mg, 542 86NU/mg±119 93NU/mg; The content of LPO in intestine and liver: endotoxin group 8 57μmol/L±2 58μmol/L, 86 97μmol/L±46 54μmol/L vs rhubarb group 3 05μmol/L±1 13μmol/L, 13 18μmol/L±19 64μmol/L). Gut histopathology revealed that rhubarb could promote proliferation of gut goblet cells, increase secretion of mucus and protect intestinal mucosa in hemorrhagic shock model. CONCLUSION The mechanism of the rhubarb on gut barrier protection might involve in decreasing intestinal permeability, scavenging oxygen free radicals, promoting proliferation of goblet cells within intestinal mucosa.

关键词： rhubarb shock, hemorrhagic endotoxin intestinal mucosa free radicals

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