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The influence of silica on reaction rates and molecular hydrogen(H_(2))generation during olivine hydrothermal alteration

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Science China Earth Sciences 2024年第1期67卷 222-233页

作者： Ruifang HUANG Weidong SUN Xing DING Yusheng ZHAO Yibing LI xiuqi shang CAS Key Laboratory of Ocean and Marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China SUSTech Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhen 518055China Center of Deep Sea Research Institute of OceanologyChinese Academy of SciencesQingdao 266071China State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Institue of Geology Chinese Academy of Geological SciencesBeijing 100037China

Hydrothermal alteration of olivine greatly influences geodynamics and the recycling of volatiles(such as water and carbon)in subduction zones.Silica is an important component of geological fluids,and its influence on the hydrothermal alteration of olivine remains poorly constrained.In this study,we performed experiments at 300–515℃ and 3.0 kbar(1 bar=10^(5)Pa)by reacting well homogenized mixtures of olivine and silica powders with saline solutions(0.5 mol L^(−1)NaCl).Silica greatly influences the reaction pathways,reaction rates,and molecular hydrogen(H_(2))formation during olivine hydrothermal alteration.In experiments at 300℃ and 3.0 kbar with mixtures of olivine and 10 wt%silica,olivine was replaced by serpentine and talc.The proportions of serpentine and talc were determined according to standard curves based on infrared spectroscopy analyses.Around 6.5%serpentine and 12%talc were produced after an experimental duration of 7 days,which had no change after a longer period(14 days).Compared to the kinetics in silica-free systems,the rates of olivine hydrothermal alteration in experiments with 10 wt%silica are much lower.The overall reaction is:4.5Forsterite+5.5SiO_(2),aq+4H_(2)O=Serpentine+2Talc.With the addition of more silica(20 wt%and 40 wt%),olivine was transformed into talc.The rates of reaction were much faster,e.g.,for experiments with olivine and 20 wt%silica,43%of talc was produced after 14 days,which increased to 77%for experiments with 40 wt%silica over the same period.The overall reaction is:3Forsterite+5SiO_(2),aq+2H_(2)O=2Talc.In experiments at 400–505℃ and 3.0 kbar,the promoting effect of silica on olivine hydrothermal alteration was also observed,which is closely associated with a decrease in Gibbs free energies of olivine hydrothermal alteration.At 300℃ and 3.0 kbar,silica decreased H_(2)formed during olivine hydrothermal alteration by around an order of magnitude,resulting in an increase in oxygen fugacity.Based on measured H_(2),we calibrated oxygen fugacities,ranging from 0.96 to 3.41 log un

关键词： Olivine hydrothermal alteration Silica Serpentinization Hydrogen Serpentine

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In-situ experiments reveal mineralization details of porphyry copper deposits

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Journal of Oceanology and Limnology 2022年第1期40卷 110-112页

作者： Weidong SUN xiuqi shang Center of Deep Sea Research Institute of OceanologyCenter for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China Laboratory for Marine Geology Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China

In-situ hydrothermal experiments using diamond-anvil cell show that sulfate and sulfi de are the dominant sulfur species under P-T conditions similar to those of porphyry magmas.No sulfi te was identifi ed using in-situ Raman spectrometer.This supports that porphyry copper mineralization is controlled by sulfate reduction,rather than sulfi te disproportionation.

关键词： diamond cell sulfate sulfi de porphyry deposits magnetite crisis

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The influence of silica on reaction rates and molecular hydrogen(H) generation during olivine hydrothermal alteration

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Science China Earth Sciences 2023年

作者： Ruifang HUANG Weidong SUN Xing DING Yusheng ZHAO Yibing LI xiuqi shang SUSTech Academy for Advanced Interdisciplinary Studies Southern University of Science and Technology Institue of Geology Chinese Academy of Geological Sciences State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Center of Deep Sea Research Institute of Oceanology Chinese Academy of Sciences CAS Key Laboratory of Ocean and Marginal Sea Geology South China Sea Institute of Oceanology Chinese Academy of Sciences

Hydrothermal alteration of olivine greatly influences geodynamics and the recycling of volatiles(such as water and carbon) in subduction zones. Silica is an important component of geological fluids, and its influence on the hydrothermal alteration of olivine remains poorly constrained. In this study, we performed experiments at 300–515°C and 3.0 kbar(1 bar=105Pa) by reacting well homogenized mixtures of olivine and silica powders with saline solutions(0.5 mol L-1NaCl). Silica greatly influences the reaction pathways, reaction rates, and molecular hydrogen(H2) formation during olivine hydrothermal alteration.In experiments at 300°C and 3.0 kbar with mixtures of olivine and 10 wt% silica, olivine was replaced by serpentine and talc. The proportions of serpentine and talc were determined according to standard curves based on infrared spectroscopy analyses.Around 6.5% serpentine and 12% talc were produced after an experimental duration of 7 days, which had no change after a longer period(14 days). Compared to the kinetics in silica-free systems, the rates of olivine hydrothermal alteration in experiments with 10 wt% silica are much lower. The overall reaction is: 4.5Forsterite+5.5SiO2,aq+4H2O=Serpentine+2Talc. With the addition of more silica(20 wt% and 40 wt%), olivine was transformed into talc. The rates of reaction were much faster, e.g.,for experiments with olivine and 20 wt% silica, 43% of talc was produced after 14 days, which increased to 77% for experiments with 40 wt% silica over the same period. The overall reaction is: 3Forsterite+5SiO2,aq+2H2O=2Talc. In experiments at400–505°C and 3.0 kbar, the promoting effect of silica on olivine hydrothermal alteration was also observed, which is closely associated with a decrease in Gibbs free energies of olivine hydrothermal alteration. At 300°C and 3.0 kbar, silica decreased H2formed during olivine hydrothermal alteration by around an order of magnitude, resulting in an increase in oxygen fugacity.Based on measured H2, we calibrated oxygen fugacities, ranging from 0

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Crustal evolution events in the Chinese continent: evidence from a zircon U-Pb database

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International Journal of Digital Earth 2020年第12期13卷 1532-1552页

作者： Yujing Wu Xianjun Fang Sisi Liao Lizhi Xue Zhe Chen Jiangnan Yang Yamin Lu Kun Ling Shengyi Hu Shuyuan Kong Yiwei Xiong Huacheng Li xiuqi shang Rui Ji Xueyun Lu Biao Song Lei Zhang Jianqing Ji Key Laboratory of Orogenic Belts and Crustal Evolution MOESchool of Earth and Space SciencesPeking UniversityBeijingPeople’s Republic of China Beijing SHRIMP Center Chinese Academy of Geological SciencesInstitute of GeologyBeijingPeople’s Republic of China Chinese Academy of Geological Sciences Institute of GeologyBeijingPeople’s Republic of China

The zircon U-Pb chronology database provides a good opportunity to obtain important zircon growth peak periods in the Earth’s history so as to study the origin and evolution of the crust.It should be noted that research preference affects the objectivity of zircon sampling,leading to hot data in the database and age statistics.To evaluate the influence of hot data on statistical results,the W and Y indexes are introduced.Using a Gaussian model of multipeak fitting of zircon U-Pb age frequencies,we identify seven major growth peaks in zircons from the Chinese continental crust,which are 2498.95,1855.82,828.88,444.29,249.46,131.96,and 58.21 Ma.Due to differences in the time scales of zircon growth peaks,these peaks can be divided into two categories:first-order zircon growth peaks(Ⅰ)and second-order zircon growth peaks(Ⅱ),which represent longer and shorter time scales,perhaps due to different kinds of geological dynamics,respectively.In addition,there are clear correspondences between these ages and various geological events recognized by most scholars,namely,the Wutai orogeny,Lvliang orogeny,Jinning orogeny,Caledonian orogeny,Indosinian orogeny,Yanshanian orogeny,and Himalayan orogeny,respectively.

关键词： Crustal evolution major geological event time scale zircon U-Pb chronology database hot data

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Zircon U-Pb geochronology of the Chinese continental crust: a preliminary analysis of the Elsevier science database

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Big Earth Data 2019年第1期3卷 26-44页

作者： Yujing Wu Xianjun Fang Sisi Liao Lizhi Xue Zhe Chen Jiangnan Yang Yamin Lu Kun Ling Shengyi Hu Shuyuan Kong Yiwei Xiong Huacheng Li xiuqi shang Rui Ji Xueyun Lu Biao Song Lei Zhang Jianqing Ji Key Laboratory of Orogenic Belts and Crustal Evolution MOESchool of Earth and Space SciencesPeking UniversityBeijingChina Beijing SHRIMP Center Institute of GeologyChinese Academy of Geological SciencesBeijingChina Institute of Geology Chinese Academy of Geological SciencesBeijingChina

The amount of zircon U-Pb geochronological data for China has grown rapidly in recent years.Nearly 410,000 items of zircon U-Pb geochronological data,representing more than 7,000 relevant articles in the Elsevier Science Database,have been collected to a database in this research.Statistics on the ages and absolute errors of these collated data,yielded smallest standard errors for(206Pb/238U),(207Pb/235U),and(207Pb/206Pb)ages within respective time intervals of3282.52 Ma.The ages and their absolute errors were determined using three main geochronology methods,based on laser ablation inductively coupled mass spectrometer(LA-ICP-MS),sensitive high-resolution ion microprobe(SHRIMP),and secondary ion mass spectrometer(SIMS)measurements.We compared the influence of these different methods on errors for each age interval.In addition,using a Gaussian model of multi-peak fitting of zircon U-Pb age frequencies,we identified seven growth peaks in zircons from the Chinese continental crust,which are 48.60 Ma,131.49 Ma,249.91 Ma,444.27 Ma,835.95 Ma,1860.65 Ma,and 2505.54 Ma.It is clear that there are correspondences between these ages and various geological events,namely,the Wutai movement,Lvliang movement,Jinning movement,Caledonian movement,Indo-China movement,Yanshan movement,and Himalayaorogeny movement,respectively.The time and spatial distributions of these zircons correspond to distinct geological events on the Chinese continent,reflecting its crustal evolution.

关键词： Zircon U-Pb geochronology Elsevier science database error LA-ICP-MS SHRIMP SIMS

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冥古代蛇纹石化过程合成氨

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Science Bulletin 2023年第11期68卷 1109-1112,M0003页

作者：商修齐黄瑞芳孙卫东 Center of Deep-Sea Research Institute of OceanologyChinese Academy of SciencesQingdao 266071China Deep-Sea Multidisciplinary Research Center Laoshan LaboratoryQingdao 266237China University of Chinese Academy of Sciences Beijing 100049China SUSTech Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhen 518055China

著名的Miller-Urey实验证明甲烷、氨气(NH3)、水蒸气和氢气在电火花下可以产生大量氨基酸,这一实验被认为是生命起源最重要的前置反应之一.然而,传统认为冥古代时期地球大气的初始成分主要包括二氧化碳和氮气(N2),在这样的中性大气里氨... 详细信息

著名的Miller-Urey实验证明甲烷、氨气(NH3)、水蒸气和氢气在电火花下可以产生大量氨基酸,这一实验被认为是生命起源最重要的前置反应之一.然而,传统认为冥古代时期地球大气的初始成分主要包括二氧化碳和氮气(N2),在这样的中性大气里氨基酸合成的效率将大大降低,氨基酸能否在早期大气中大量合成仍然存在争议.为解决这一难题,我们进行了“橄榄岩十水+氮气(+二氧化碳)”的高温高压实验.实验结果证明氮气参与蛇纹石化过程,产生氨基酸合成的关键原料——氨.考虑到蛇纹石化过程中同样可以产生大量甲烷,在冥古代地表广泛的蛇纹石化作用下,原始大气的成分将会从以二氧化碳和氮气为主演化为以甲烷和氨气为主,为大气中氨基酸的合成创造了适宜条件.

关键词：蛇纹石化地球大气二氧化碳氨基酸合成生命起源橄榄岩冥古代实验证明

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Power-law patterns in the Phanerozoic sedimentary records of carbon, oxygen, sulfur,and strontium isotopes

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Journal of Palaeogeography 2024年第1期13卷 116-126页

作者： Haitao shang Institute of Ecology and Evolution University of OregonEugeneOR97403USA

Power-law patterns appear in a variety of natural systems on the modern Earth;nevertheless,whether such behaviors appeared in the deep-time environment has rarely been studied. Isotopic records in sedimentary rocks, which are widely used to reconstruct the geological/geochemical conditions in paleoenvironments and the evolutionary trajectories of biogeochemical cycles, offer an opportunity to investigate power laws in ancient geological systems. In this study, I focus on the Phanerozoic sedimentary records of carbon, oxygen, sulfur, and strontium isotopes, which have well documented and extraordinarily comprehensive datasets. I perform statistical analyses on these datasets and show that the variations in the sedimentary records of the four isotopes exhibit power-law behaviors. The exponents of these power laws range between 2.2 and 2.9;this narrow interval indicates that the variations in carbon, oxygen, sulfur, and strontium isotopes likely belong to the same universality class, suggesting that these systematic power-law patterns are governed by universal, scale-free mechanisms. I then derive a general form for these power laws from a minimalistic model based on basic physical principles and geosystem-specific assumptions, which provides an interpretation for the power-law patterns from the perspective of thermodynamics. The fundamental mechanisms regulating such patterns might have been ubiquitous in paleoenvironments, implying that similar power-law behaviors may exist in the sedimentary records of other isotopes.

关键词： Power laws Phanerozoic sedimentary records Carbon isotope(δ~(13)C) Oxygen isotope(δ~(18)O) Sulfur isotope(δ~(34)S) Strontium isotope(~(87)Sr/~(86)Sr)

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Review on Security Defense Technology Research in Edge Computing Environment

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Chinese Journal of Electronics 2024年第1期33卷 1-18页

作者： Ke shang Weizhen HE Shuai ZHANG National Digital Switching System Engineering and Technological R&D Center

Edge computing, which achieves quick data processing by sinking data computing and storage to the network edge, has grown rapidly along with the Internet of things. The new network architecture of edge computing brings new security challenges. Based on this, this paper investigates the edge computing security literature published in recent years and summarizes and analyzes research work on edge computing security from different attack surfaces. We start with the definition and architecture of edge computing. From the attack surface between device and edge server, as well as on edge servers, the research describes the security threats and defense methods of edge computing. In addition, the cause of the attack and the pros and cons of defense methods is introduced. The challenges and future research directions of edge computing are given.

关键词： Edge computing Security Threat Defense Architecture Attack surface

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Cybersecurity Landscape on Remote State Estimation:A Comprehensive Review

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 851-865页

作者： Jing Zhou Jun shang Tongwen Chen the Department of Electrical and Computer Engineering University of AlbertaEdmonton AB T6G 1H9Canada the Department of Control Science and Engineering and shanghai Research Institute for Intelligent Autonomous Systems Tongji UniversityShanghai 200092China

Cyber-physical systems(CPSs)have emerged as an essential area of research in the last decade,providing a new paradigm for the integration of computational and physical units in modern control systems.Remote state estimation(RSE)is an indispensable functional module of CPSs.Recently,it has been demonstrated that malicious agents can manipulate data packets transmitted through unreliable channels of RSE,leading to severe estimation performance degradation.This paper aims to present an overview of recent advances in cyber-attacks and defensive countermeasures,with a specific focus on integrity attacks against RSE.Firstly,two representative frameworks for the synthesis of optimal deception attacks with various performance metrics and stealthiness constraints are discussed,which provide a deeper insight into the vulnerabilities of RSE.Secondly,a detailed review of typical attack detection and resilient estimation algorithms is included,illustrating the latest defensive measures safeguarding RSE from adversaries.Thirdly,some prevalent attacks impairing the confidentiality and data availability of RSE are examined from both attackers'and defenders'perspectives.Finally,several challenges and open problems are presented to inspire further exploration and future research in this field.

关键词： Cyber-attacks Kalman filtering remote state estimation unreliable transmission channels

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Target parameter estimation for OTFS-integrated radar and communications based on sparse reconstruction preprocessing

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Frontiers of Information Technology & Electronic Engineering 2024年第5期25卷 742-754页

作者： Zhenkai ZHANG Xiaoke shang Yue XIAO Ocean College Jiangsu University of Science and TechnologyZhenjiang 212003China

Orthogonal time-frequency space(OTFS)is a new modulation technique proposed in recent years for high Doppler wireless scenes.To solve the parameter estimation problem of the OTFS-integrated radar and communications system,we propose a parameter estimation method based on sparse reconstruction preprocessing to reduce the computational effort of the traditional weighted subspace fitting(WSF)algorithm.First,an OTFS-integrated echo signal model is constructed.Then,the echo signal is transformed to the time domain to separate the target angle from the range,and the range and angle of the detected target are coarsely estimated by using the sparse reconstruction algorithm.Finally,the WSF algorithm is used to refine the search with the coarse estimate at the center to obtain an accurate estimate.The simulations demonstrate the effectiveness and superiority of the proposed parameterestimation algorithm.

关键词： Integrated radar and communications system Orthogonal time-frequency space Target parameter estimation Sparse reconstruction Weighted subspace fitting

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