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Phase equilibrium modeling of zircon stability in mantle peridotite:Implication for crust-mantle interaction

Science China Earth Sciences 2022年第2期65卷 282-298页

作者： Hua XIANG Jianping ZHENG Yibing LI zeming zhang Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China School of Earth Sciences State Key Laboratory of Geological Processes and Mineral ResourcesChina University of GeosciencesWuhan 430074China

Zircon is a common accessory mineral in various rocks,especially in the crustal *** is the best mineral for U-Pb ***,trace elements and isotopes of the mineral can also provide much information concerning the formation and evolution of *** are a growing number of reports of zircon existing in mantle ***,it is generally considered that zircon is unlikely crystallized in ultrabasic rocks due to SiO_(2)-*** this paper,the SiO_(2) activity and zircon/baddeleyite transition curve at different conditions were calculated through thermodynamic phase equilibrium modeling,to reveal the main factors affecting the SiO_(2) activity and the stability of zircon/baddeleyite in ultrabasic and basic rocks,especially in mantle *** results provide a thermodynamic basis for interpreting the genesis and significance of zircon in mantle *** is,the SiO_(2) activity is mainly controlled by stable mineral assemblages and temperature-pressure *** orthopyroxene+olivine assemblage in peridotite as an effective buffer restricts the SiO_(2) activity in a relatively high range with a small *** upper temperature limit of zircon can reach more than 1500℃ with this mineral *** the low-temperature serpentinization of peridotite,the replacement of olivine and pyroxene by serpentine can result in a significant decrease of SiO_(2) activity,and baddeleyite can be stabilized at<530℃ and<2.7 *** peridotite is strongly metasomatized by the SiO_(2)-bearing fluid,the addition of SiO_(2) can increase its activity and make zircon stable at low *** SiO_(2) activity in ultrabasic-basic rocks is not only positively correlated with the SiO_(2) content but also negatively correlated with the Ca and Na contents of *** is because Ca and Na preferentially combine with Si and Al to form Si-rich minerals,such as clinopyroxene and *** process will consume excessive SiO_(2),decreasing

关键词： Zircon Baddeleyite Phase equilibrium modeling Mantle peridotite Ultrabasic rock

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The compositional zoning of garnet in eclogite from western segment of Altyn Tagh, northwestern China and its dynamic significance

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Chinese Science Bulletin 2000年第1期45卷 79-83页

作者： zhang zeming YANG Yong zhang Jianxin Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China Analyses and Test Center China University of Geosciences(Wuhan)Wuhan 430074China

The eclogites from the Altyn Tagh, northwestern China have been subjected to medium-temperature and high-pressure metamorphism, and then overprinted by the amphibolite to granulite facies retrograde metamorphism, A complex compositionai zoning was well preserved in the garnet porphyroblast formed during the metamorphism of eclogite facies. This zoning recorded P-T path of multistage metamorphism, and an early retrogressive process with features of decreasing pressure and increasing temperature. This evidences a short residence time for the eclogite at peak metamorphism and early retrogression, and thus rapid tectonic uplift history.

关键词： eclogite garnet growth zoning P-7 path exhumation rate Altyn Tagh.

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Metamorphic P-T-t Path of UHT Granulites from the North Tongbai Orogen, Central China

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Journal of Earth Science 2018年第5期29卷 1116-1131页

作者： Hua Xiang zeming zhang Liming Zhao Zengqiu Zhong Hanwen Zhou Key Laboratory of Deep-Earth Dynamics Institute of Geology Chinese Academy of Geological Sciences School of Earth Sciences and Resources China University of Geosciences School of Earth Sciences China University of Geosciences

Although zircon U-Pb geochronometer has been widely used for dating metamorphism in moderate- to high-grade metamorphic rocks, it is still difficult to link the zircon U-Pb age to pressure and temperature （P-T） conditions. In this study, zircon trace elements and Hf isotopes and REE partitioning between zircon and garnet are adopted to track the formation condition of zircon in the granu- lites from North Tongbai Orogen, Central China. Combined with previous metamorphic P-T path results, a quantitative integrated anticlockwise P-T-t path was established for Tongbai granulites. These grauulites recorded an early low-P heating followed by a dramatic pressure increase. Evidence for the prograde history （M1） is provided by cordierite, orthopyroxene and biotite inclusions in garnet. The prograde metamorphism occurred at around 443±3 Ma, with P-T conditions of ca. 730-820 ℃ and 〈6 kbar. The peak metamorphic （M2） condition is 〉920 ℃ and 8.5-10 kbar and the peak metamorphism age is ca. 432±4 Ma. At around 419 Ma, the granulites suffered an amphibolite-facies retrograde metamorphism （M3）, represented by the replacement of garnet by biotite and plagioclase, and clinopyroxene by amphibole, with metamorphic condition of ca. 700℃ and ca. 7 kbar. The last retrograde metamorphism （M4） is a greenschist-facies overprint with an age of ca. 404 Ma. It is concluded that the meta- morphism of Tongbai granulite lasted for more than 40 Ma, including a stage of more than 20 Ma granulitc-facies metamorphism. The prolonged granulite-facies metamorphism resulted from the continuous northward subduction of the Shangdan oceanic crust beneath the North Qinling terrane.

关键词： granulites zircon U-Pb dating P-T-t path trace element Ln-Hf isotope Tongbai Orogen.

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The ages of U-Pb and Sm-Nd for eclogite from the western segment of Altyn Tagh tectonic belt——Evidence for existence of Caledonian orogenic root

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Chinese Science Bulletin 1999年第24期44卷 2256-2259页

作者： Jianxin zhang zeming zhang Zhiqin Xu Jingsui Yang Junwen Cui Chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China

The eclogites of Altyn Tagh tectonic belt occur as lens within gneisses characterized by amphibolite-facies mineral parageneses. The well-preserved eclogite is selected for Sm-Nd and U-Pb isotopic dating. The Sm-Nd isotopic data yield a whole rock-garnet-omphacite isochron of (500 ?10) Ma. The U-Pb isotopic measurements of zircons show that the four

关键词： Altyn Tagh tectonic belt eclogite Sm-Nd dating U-Pb dating.

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Orbital Interception Pursuit Strategy for Random Evasion Using Deep Reinforcement Learning

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Space(Science & Technology) 2023年第1期3卷 606-619页

作者： Rui Jiang Dong Ye Yan Xiao Zhaowei Sun zeming zhang Research Center of Satellite Technology School of AstronauticsHarbin Institute of TechnologyHarbinChina Space Missions Engineering Lab Department of Aerospace Science and TechnologyPolitecnico di MilanoMilanoItaly

Aiming at the interception problem of noncooperative evader spacecraft adopting random maneuver strategy in one-to-one orbital pursuit-evasion problem,an interception strategy with decision-making training mechanism for the pursuer based on deep reinforcement learning is *** core purpose is to improve the success rate of interception in the environment with high *** of all,a multi-impulse orbit transfer model of pursuer and evader is established,and a modular deep reinforcement learning training method is ***,an effective reward mechanism is proposed to train the pursuer to choose the impulse direction and impulse interval of the orbit transfer and to learn the successful interception strategy with the optimal fuel and ***,with the evader taking a random maneuver decision in each episode of training,the trained decision-making strategy is applied to the pursuer,the corresponding interception success rate of which is further *** results show that the pursuer trained can obtain universal and variable interception *** each round of pursuit-evasion,with random maneuver strategy of the evader,the pursuer can adopt similar optimal decisions to deal with high-dimensional environments and thoroughly random state space,maintaining high interception success rate.

关键词： pursuit mechanism thoroughly

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Fast Response Fluorescent Probe with a Large Stokes Shift for Thiophenol Detection in Water Samples and Cell Imaging

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Journal of Analysis and Testing 2023年第1期7卷 69-78页

作者： Jinjie You Hua Liu Qiaofen Pan Aili Sun zeming zhang Xizhi Shi State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products School of Marine SciencesNingbo UniversityNingbo 315211China College of Food and Pharmaceutical Sciences Ningbo UniversityNingbo 315211China

Herein,the 2,4-dinitrophenyl functional group acting as the thiophenol reactive site was introduced into a carbazole-chalcone fluorophore to synthesize probe-CCF2,which could result in a remarkable increase in fluorescence when reacting with *** selectivity and accuracy of probe-CCF2 were investigated with thiophenols,hydrosulphide salt,aliphatic thiols,glutathione,cysteine,anions and metal ***-CCF2 exhibited a detection limit of 37 nmol/L(R^(2)=0.9951),a remarkable Stokes shift of approximately 130 nm,and a brief response time of 9 min with a remarkable increase in fluorescence of ***-CCF2 was applied for thiophenol detection in water samples and imaging in living cells successfully,with high sensitivity and excellent selectivity.

关键词： Thiophenol Large Stokes shift Fluorescent probe Water sample Cell imaging

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Micro-area Chemical Composition and Preserved P-T Evolution Trace of Phengite in Albite Gneiss from the Donghai Ultrahigh-Pressure Metamorphic Area,East China

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Acta Geologica Sinica(English Edition) 2000年第2期74卷 183-189页

作者： LIU Fulai zhang zeming XU Zhiqin YANG Jingsui XU Huifen Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China

Study of micro-area chemical compositions indicates that phengite in albite gneiss from hole ZK2304 of the Donghai region has evident compositional zoning. SiO2 and tetrahedrally coordinated Si contents decrease, and Al2O3, AlIVand AlVIcontents increase gradually from core to rim. However, K2O, MgO and FeO contents basically remain unchanged from core to rim. According to P-T estimates obtained from geothermometers and barometers, combined with previous experimental data, the core belt (micro-area I) of phengite was formed at T=637–672°C and P=1.55–1.73 GPa, and the transitional belt (micro-area II) of the phengite were formed at T=594–654°C and P=1.35–1.45 GPa. Towards the rim belt (micro-area III), the temperature decreased slightly, but the pressure decreased rapidly with T=542–630°C and P=1.12–1.19 GPa. The P-T evolution path recorded by the compositional zoning of phengite is characterized by significant near-isothermal decompression, revealing that the gneiss has undergone high-pressure-ultrahigh-pressure metamorphism. The compositional zoning of the phengite in the albite gneiss may have formed in the geodynamic process of rapid exhumation in the Sulu ultrahigh-pressure metamorphic belt.

关键词： phengite compositional zoning gneiss genetic mechanism Donghai drill hole

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Effects of system parameters on bright dissipative holographic photovoltaic solitons

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Chinese Science Bulletin 2008年第8期53卷 1138-1144页

作者： LIU ShiXiong LIU JinSong CAI Xin FAN Ting zhang GuangYong Du zeming Wuhan National Laboratory for Optoelectronics School of Optoelectronics Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China

In a photovoltaic dissipative system, evolution and stability of a bright dissipative holographic photo- voltaic (DHP) soliton are completely determined by the given dissipative system, i.e., they are impacted by the system parameters, such as the system temperature, the photovoltaic field of the crystal, the angle between two input beams, and the angle of polarized direction. Such DHP solitons can be easily amplified or absorbed by adjusting these system parameters. They have potential applications in op- tical switches or repeaters.

关键词：光电孤子光电耗损系统进化性稳定性

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The Eocene corundum-bearing rocks in the Gangdese arc, south Tibet:Implications for tectonic evolution of the Himalayan orogen

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Geoscience Frontiers 2018年第5期9卷 1337-1354页

作者： zeming zhang Huixia Ding Xin Dong Zuolin Tian Hongchen Mu Mengmei Li Shengkai Qin Zhixiang Niu Ning zhang Institute of Geology Chinese Academy of Geological Sciences School of Earth Sciences and Resources China University of Geosciences Beijing

The genesis of Liangguo corundum deposit in the southern Gangdese magmatic arc, east-central Himalaya, remains unknown. The present study shows that the corundum-bearing rocks occur as lenses with variable sizes in the Eocene gabbro that intruded into marble. These corundum-bearing rocks have highly variable mineral assemblage and mode. The corundum-rich rocks are characterized by containing abundant corundum, and minor spinel, ilmenite and magnetite, whereas the corundum-poor and corundum-free rocks have variable contents of spinel, plagioclase, sillimanite, cordierite, ilmenite and magnetite. The host gabbro shows variable degrees of hydration and carbonization. The corundum grains are mostly black, and rarely blue, and have minor Fe O and TiO_2. The spinel is hercynite, with high Fe O and low Mg O contents. The corundum-bearing rocks have variable but high Al_2O_3, FeO and TiO_2, and low SiO_2 contents. Inherited magmatic and altered zircons of the corundum-bearing rocks have similar U e Pb ages(~47 Ma) to the magmatic zircons of the host gabbro, indicating corundum-bearing rock formation immediately after the gabbro intrusion. We considered that emplacement of gabbro induced the contact metamorphism of the country-rock marble and the formation of silica-poor fluid. The channeled infiltration of generated fluid in turn resulted in the hydrothermal metasomatism of the gabbro, which characterized by considerable loss of Si from the gabbro and strong residual enrichment of Al. The metasomatic alteration probably formed under Pe T conditions of ~2.2 -2.8 kbar and ~650 -700℃. We speculate that SiO_2, CaO and Na_2O were mobile, and Al_2O_3, FeO, TiO_2 and high field strength elements remained immobile during the metasomatic process of the gabbro. The Liangguo corundum deposit, together with metamorphic corundum deposits in Central and Southeast Asia, were related to the Cenozoic Himalayan orogeny, and therefore are plate tectonic indicators.

关键词： Corundum deposit Gangdese magmatic arc Metasomatism Gabbro Himalayan orogen

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Petrogenesis and Tectonic Implications of the Latest Cretaceous Intrusive Rocks from the Eastern Gangdese Belt,Southeast Tibet

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Acta Geologica Sinica(English Edition) 2022年第3期96卷 891-903页

作者： CHEN Yanfei CHEN Xuanhua zhang zeming SHAO Zhaogang TIAN Zuolin DONG Xin QIN Shengkai YUAN Yuelei Chinese Academy of Geological Sciences Beijing 100037China School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China

The latest Cretaceous magmatic activity in the eastern segment of the Lhasa terrane provides important insights for tracking the magma source and geodynamic setting of the eastern Gangdese batholith,eastward of eastern Himalayan *** petrological,geochemical and geochronological studies of the intrusive rocks(monzodiorites and granodiorites)of the eastern Gangdese batholith are presented with monzodiorites and granodiorites giving zircon U-Pb crystallization dates of 70-66 Ma and 71-66 Ma withεHf(t)values of−4.8 to+6.2 and−1.9 to+5.3,*** rocks are metaluminous to weakly peraluminous I-type granites showing geochemically arc-related features of enrichment in LREEs and some LILEs,e.g.,Rb,Th,and U,and depletion in HREEs and some HFSEs,e.g.,Nb,Ta,and *** rocks are interpreted to be derived from partial melting of mantle material and juvenile crust,respectively,which are proposed to be triggered by Neo-Tethyan slab rollback during northward subduction,with both experiencing ancient crustal *** studied intrusive rocks formed in a transitional geodynamic setting caused by Neo-Tethyan oceanic flat subduction to slab rollback beneath the eastern Gangdese belt during the latest Cretaceous.

关键词： Neo-Tethyan ocean slab rollback regional tectonics eastern Gangdese batholith Tibet

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