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The existence of saturated vapors in the deep source region of 2017Pohang earthquake evidenced from seismic tomography

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earth and Planetary Physics 2024年第5期8卷 811-821页

作者： JiaWei Qian HaiJiang Zhang Lei Guo Uzonna Okenna Anyiam Changsoo Cho Kang Hyeun Ji HaoRan Ma school of Carbon Neutrality Science and Engineering Anhui University of Science and Technology College of Oceanography Hohai University Laboratory of Seismology and Physics of earth's Interior School of Earth and Space Sciences University of Science and Technology of China Hebei earthquake Agency Geological and Environmental Science Hope College earthquake Research Center Korea Institute of Geoscience and Mineral Resources

Geothermal resources are a promising approach to clean renewable energy; 90% of them are deep reservoirs of hot dry rock that require hydraulic fracturing to create a network of connections among wells to enable efficient heat exchange, known as an Enhanced Geothermal System（EGS）. The Pohang EGS project in south Korea led to a devasting Mw5.5 earthquake, triggered by the reservoir's EGS stimulation, the largest earthquake known to have been induced by EGS development. Detailed investigations have been conducted to understand the cause of the Pohang earthquake; the conclusion has been that overpressurized injected fluids migrated into an unknown fault triggering this large earthquake. Detailed velocity images for the source zone of the 2017 Pohang earthquake,which could be helpful for further understanding its inducing mechanism, are unavailable. However, we have assembled detailed aftershock data recorded by 41 local stations installed within about three months after the Mw5.5 Pohang earthquake, and have then applied the Vp/Vsmodel's consistency-constrained double-difference seismic tomography method to determine the high-resolution three-dimensional Vp（compressional wave velocity）, Vs（shear wave velocity）, and Vp/Vsmodels of the source region that we report here,as well as earthquake locations within the source region. The velocity images reveal that the deep source area of the 2017 Pohang earthquake is dominated by low Vp, high Vs, and low Vp/Vsanomalies, a pattern that can be caused by overpressurized vapors due to high temperatures at these depths. Based on aftershock locations and velocity features, our studies support the conclusion that the 2017Pohang earthquake was triggered by injected EGS fluids that migrated into a blind fault.

关键词： Pohang earthquake tomoDDMC low Vp/Vs saturated vapors EGS

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Challenges and opportunities in Quaternary palynology

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Science China earth sciences 2024年第7期67卷 2148-2161页

作者： Qinghai XU Houyuan LU Zhuo ZHENG College of Geographical sciences Hebei Key Laboratory of Environmental Change and Ecological ConstructionHebei Normal UniversityShijiazhuang 050024China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China school of earth sciences and Engineering Sun Yat-sen UniversityZhuhai 519082China

Quaternary palynology plays a pivotal role in investigating global climate change and various other research fields,serving as an essential tool for the quantitative analysis of paleoenvironment ***,due to the vast diversity of terrestrial ecosystems and intricate interactions between vegetation,climate,and human activities,further advancements are required in the following aspects within this discipline.(1)The accuracy of classification in pollen morphology and fossil pollen identification needs improvement,particularly at the species *** represents a significant challenge in present Quaternary ***-aided intelligent recognition holds promise as a solution for species identification based on more detail pollen morphology.(2)Most pollen-based vegetation and climate reconstructions overlook the significance of bare *** bare ground can lead to substantial inaccuracies when quantitatively reconstructing past vegetation and climate.(3)While pollen records provide reliable information on paleoclimate changes,current quantitative climate reconstruction models heavily rely on modern pollen datasets derived from present-day vegetation disturbed more or less by human *** introduces bias and uncertainties into paleoclimate reconstruction.(4)Although pollen can serve as an indicator of human activities,accurately quantifying the intensity of human influence remains *** accurate identification of crop pollen,reconstructing reliable land cover/use data,and integrating multidisciplinary data may enhance the identification and quantification of signals related to human activity in pollen records.

关键词： Quaternary palynology Paleoclimate Paleovegetation Human activity

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In situ formed Mg(BH_(4))_(2) for improving hydrolysis properties of MgH_(2)

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Journal of Magnesium and Alloys 2024年第3期12卷 1204-1214页

作者： Yongyang Zhu Mili Liu liming Zeng Yin Wang Daifeng Wu Rui Li Qing Zhou Renheng Tang Fangming Xiao Institute of Resources Utilization and Rare earth Development Guangdong Provincial Key Laboratory of Rare Earth Development and ApplicationGuangdong Academy of SciencesGuangzhou 510650China school of Materials Science and Engineering Guangdong Provincial Key Laboratory of Advanced Energy Storage MaterialsSouth China University of TechnologyGuangzhou 510641China

The hydrolysis of MgH_(2) delivers high hydrogen capacity(15.2 wt%),which is very attractive for real-time hydrogen ***,the formation of a surface passivation Mg(OH)_(2) layer and the large excess of H_(2)O required to ensure complete hydrolysis are two key challenges for the MgH_(2) hydrolysis ***,a low-cost method is reported to synthesize MgH_(2)@Mg(BH_(4))_(2) composite via ball-milling MgH_(2) with cheap and widely available B_(2)O_(3)(or B(OH)_(3)).By adding small amounts of B_(2)O_(3),the in-situ formed Mg(BH_(4))_(2) could significantly promote the hydrolysis of MgH_(2).In particular,the MgH_(2)–10 wt%B_(2)O_(3) composite releases 1330.7 mL·g^(−1) H_(2)(close to 80%theoretical hydrogen generation H_(2))in H_(2)O and 1520.4 mL·g^(−1) H_(2)(about 95%)in 0.5 M MgCl_(2) in 60 min at 26℃ with hydrolysis rate of 736.9 mL·g^(−1)·min^(−1) and 960.9 mL·g^(−1)·min^(−1) H_(2) during the first minute of the hydrolysis,*** addition,the MgCl_(2) solution allows repeated use by filtering and exhibits high cycle stability(20 cycles),therefore leading to much reduced capacity loss caused by the excess H_(2)*** show that by introducing B_(2)O_(3) and recycling the 0.5 M MgCl_(2) solution,the system hydrogen capacity can approach 5.9 wt%,providing a promising hydrogen generation scheme to supply hydrogen to the fuel cells.

关键词： Hydrolysis MgH_(2) Mg(BH_(4))_(2) Hydrogen generation B_(2)O_(3) MgCl_(2)

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Amelioration of habitat since the early Holocene contributed to the origin of agriculture in the farming-pastoral zone of northern China

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Science China earth sciences 2024年第8期67卷 2535-2546页

作者： Xin JIA Zhiping ZHANG Yonggang SUN Runqi JIANG Shuangwen YI Wei CHEN Jue SUN Guoqiang LI Shuzhi WANG Enrui LI Xiaonong HU Qingchun BAO Harry F.LEE Huayu LU Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China Schlool of History and Culture Chifeng UniversityChifeng 024000China school of geography and Ocean Science Nanjing UniversityNanjing 210023China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China Key Laboratory of Western China’s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China Institute of Archaeology Chinese Academy of Social SciencesBeijing 100710China Ulanqab Museum Ulanqab 012000China The Institute of Cultural Relics and Archaeology Hohhot 010011China Department of geography and Resource Management The Chinese University of Hong KongHong Kong 999077China Key Laboratory of Virtual Geographic Environment(Ministry of Education of PRC) Nanjing Normal UniversityNanjing 210023China school of geography Nanjing Normal UniversityNanjing 210023China Institute of Environmental Archaeology Nanjing Normal UniversityNanjing 210023China

The origin of agriculture in the farming-pastoral zone of northern China remains in *** central region of the Inner Mongolia Plateau is located in the core area of the farming-pastoral zone;thus,it is a critical region for exploring the origin of the dryland farming system in northern *** study selected the Yumin Site and Banan Site,which belong to the Yumin Culture-the beginning of Neolithic culture in Inner Mongolia-as the research *** on the quartz optically stimulated luminescence(OSL)dating on the sedimentary sections from the Yumin site(YM)and Banan site(BN1 and BN2),the Holocene chronology framework of each section was *** that,by identifying carbonized grains in the Yumin site and the multi-proxy analysis of each section,we investigated the relationship between the origin of agriculture and climate change in this *** results revealed that the timing of the origin of agriculture recorded in the Yumin site lagged behind the timing of a significant increase of precipitation during the early Holocene but coincided with the timing of a significant increase of vegetation around 8.4 *** phenomenon was further confirmed by the published high-resolution paleoenvironmental records from the surrounding area of the Yumin *** propose that with the gradual amelioration of hydrothermal conditions since the beginning of the Holocene,the regional ecosystem had been improved,resulting in the gradual conversion of the land surface from infertile sand to organic-rich soil,providing an appropriate environmental foundation for the origin of dryland farming in northern China around 8.4 *** study highlighted that the“accumulative environmental effects”during the early Holocene played a vital role in the origin of agriculture in northern China and provided a reference for agricultural management in the context of future climate change.

关键词： Origin of agriculture Accumulative environmental effects Yumin Culture Northern China Holocene

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Long-lived lunar volcanism sustained by precession-driven core-mantle friction

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National Science Review 2024年第2期11卷 114-123页

作者： Shuoran Yu Xiao Xiao Shengxia Gong Nicola Tosi Jun Huang Doris Breuer Long Xiao Dongdong Ni State Key Laboratory of Lunar and Planetary sciences Macau University of Science and Technology Planetary Science Institute State Key Laboratory of Geological Processes and Mineral Resources School of Earth Sciences China University of Geosciences CAS Key Laboratory of Planetary sciences Shanghai Astronomical Observatory Institute of Planetary Research German Aerospace Centre(DLR)

Core-mantle friction induced by the precession of the Moon's spin axis is a strong heat source in the deep lunar mantle during the early phase of a satellite's evolution, but its influence on the long-term thermal evolution still remains poorly explored. Using a one-dimensional thermal evolution model, we show that core-mantle friction can sustain global-scale partial melting in the upper lunar mantle until ～3.1 Ga, thus accounting for the intense volcanic activity on the Moon before ～3.0 Ga. Besides, core-mantle friction tends to suppress the secular cooling of the lunar core and is unlikely to be an energy source for the long-lived lunar core dynamo. Our model also favours the transition of the Cassini state before the end of the lunar magma ocean phase(～4.2 Ga), which implies a decreasing lunar obliquity over time after the solidification of the lunar magma ocean. Such a trend of lunar obliquity evolution may allow volcanically released water to be buried in the lunar regolith of the polar regions. As a consequence, local water ice could be more abundant than previously thought when considering only its accumulation caused by solar wind and comet spreading.

关键词： Moon precession orbit volcanism

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Concurrence of high dust aerosol and stratosphere-intruded ozone pollution in super sandstorms

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Science Bulletin 2024年第16期69卷 2509-2513页

作者： Zhixiong Chen Jane Liu Xiushu Qie Xugeng Cheng Mengmiao Yang Lei Shu Jing M.Chen Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education School of Geographical SciencesFujian Normal UniversityFuzhou 350117China Key Laboratory of Atmospheric Environment and Extreme Meteorology Chinese Academy of SciencesBeijing 100029China Department of geography and Planning University of TorontoToronto M5S 3G3Canada Key Laboratory of Middle Atmosphere and Global Environment Observation(LAGEO) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of earth and Planetary Science University of Chinese Academy of SciencesBeijing 100049China

The air quality in China has substantially improved in recent years,as indicated by the declining trends in SO_(2),NO_(2),PM_(2.5)and PM_(10)*** the reduced anthropogenic pollutant emissions;however,sustained increases in surface ozone(O_(3))that may impair the effectiveness of clean air actions have been ***,complex heavy pollution episodes can still occur,and some of these episodes are closely linked with *** example,two severe sandstorms occurred successively in the early spring of 2021 in North China,despite the sandstorm frequency in China having significantly decreased in recent years[1-3].

关键词： ozone sands aerosol

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快速干湿气候振荡与中国古代大规模社会动荡

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Science Bulletin 2024年第3期69卷 314-318页

作者：孟先强张灿李根程鉴如蔡洁刘一兰霍利倪振宇张恩楼 State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 21008China Department of earth Science University of CaliforniaSanta Barbara CA 93106USA Ministry of Education Key Laboratory of Surficial Geochemistry School of Earth Sciences and EngineeringNanjing UniversityNanjing 210023China

Climate conditions have long been acknowledged as a pivotal factor shaping regional productivity and influencing available resources,consequently playing an important role in driving social changes throughout human history[1–3].In ancient East Asia,the Chinese agrarian civilization emerged around 4000 years ago in northern China,the region termed the“Central Plains”.This region faced recurrent episodes of large-scale social unrest,profoundly impacting the societal structure and dynastic cycles[4].These episodes were marked by extended civil peasant uprisings and/or incursions from northern nomadic tribes,often spanning decades to centuries[5].Both the agrarian societies in the Central Plains and the husbandry-based nomadic tribes in the vast northern grasslands,characterized by semi-arid and semi-humid climates,were notably sensitive to climate variations[6].

关键词： husbandry driving profound

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Sustainable all-weather CO2 utilization by mimicking natural photosynthesis in a single material

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National Science Review 2024年第2期11卷 177-187页

作者： Xianjin Shi Yu Huang Ran Long Zhenyu Wang Liqin Wang Junji Cao Gangqiang Zhu Yujie Xiong State Key Laboratory of Loess and Quaternary Geology(SKLLQG) Key Laboratory of Aerosol Chemistry and Physics Institute of Earth EnvironmentChinese Academy of Sciences Center of Excellence in Quaternary Science and Global Change Chinese Academy of Sciences University of Chinese Academy of sciences Hefei National Research Center for Physical sciences at the Microscale School of Chemistry and Materials Science and National Synchrotron Radiation Laboratory University of Science and Technology of China Institute of Atmospheric Physics Chinese Academy of Sciences school of Physics and Information Technology Shaanxi Normal University

Solar-driven CO2conversion into hydrocarbon fuels is a sustainable approach to synchronously alleviating the energy crisis and achieving net ***,the dependence of the conversion process on solar illumination hinders its practical application due to the intermittent availability of sunlight at night and on cloudy or rainy ***,we report a model material of Pt-loaded hexagonal tungsten trioxide（Pt/h-WO3） for decoupling light and dark reaction processes,demonstrating the sustainable CO2conversion under dark conditions for the first *** such a material system,hydrogen atoms can be produced by photocatalytic water splitting under solar illumination,stored together with electrons in the h-WO3through the transition of W6+to W5+and spontaneously released to trigger catalytic CO2reduction under dark ***,we demonstrate using natural light that CH4production can persist at night and on rainy days,proving the accomplishment of all-weather CO2conversion via a sustainable way.

关键词： sustainable CO2 utilization artificial photosynthesis all-weather application charge storage

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Altered oceanic crust source for the alkaline rocks with superchondritic Nb/Ta ratios due to the steep subduction

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Journal of earth Science 2024年

作者： Xu Zhao Ning-Bo Li He-Cai Niu Shu-Cheng Tan Department of Geology， school of earth sciences， Yunnan University CAS Key Laboratory of Mineralogy and Metallogeny， Guangzhou Institute of Geochemistry， Chinese Academy of sciences CAS Center for Excellence in Deep earth Science

The cause resulting in alkaline rocks with superchondritic Nb/Ta ratios remains a geochemical enigma. This paper present zircon and apatite geochronology， mineralogy， geochemistry， and Nd-Hf-Zn isotope investigation on the Ejinao nepheline syenite from South China to constrain the petrogenesis of alkaline rocks. The occurrence of alkaline minerals， including alkaline feldspar， arfvedsonite， and nepheline， indicate an alkaline feature of the Ejinao nepheline syenite. Zircon and apatite from the rock show U-Pb concordia age of 135.4±0.9 Ma and 137.5±5.8Ma， respectively， suggesting generation in the Early Cretaceous. The rock is characterized by low MgO （0.17 wt.%–0.26 wt.%） contents， but high Fe2O3T（4.66 wt.%–6.16 wt.%） and total alkalis (Na2O + K2O = 12.1 wt.%–13.1 wt.%) contents， consistent with the melts from subducting oceanic crust rather than mantle peridotite. The rock has low TiO2（0.13 wt.%–0.21 wt.%） contents and superchondritic Nb/Ta and Zr/Hf ratios， resulting from rutile residue in the source area. The εNd（t）（-1.35 to -1.09）， εHf（t）（-3.03 to -1.52）， and δ66Zn （0.32‰ to 0.34‰） values of the nepheline syenite manifest the involvement of 15%–20% carbonate-bearing sediments in the altered oceanic crust. Geochemical modeling further reveals that the nepheline syenite was sourced from 10%–20% melting of such a source. This superchondritic Nb/Ta nepheline syenite was generated during the steep subduction of the Paleo-Pacific Ocean， which is needed to bring oceanic slab to a hot mantle and resulted in the altered oceanic crust melting. Our study highlights that the altered oceanic crust represents a novel source for superchondritic Nb/Ta alkaline rocks.

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Emerging glacier forelands alter carbon dynamics on the Tibetan Plateau

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Journal of Mountain Science 2024年第9期21卷 2871-2875页

作者： GAO Tanguang ZHANG Yulan MEADOWS Michael Edward College of earth and Environmental sciences Lanzhou UniversityLanzhou 730000China Key Laboratory of Cryospheric Science and Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China school of geography and Ocean sciences Nanjing UniversityNanjing 210023China Department of Environmental&Geographical Science University of Cape TownRondebosch 7701South Africa

The critical challenge of ongoing climate warming is resulting in glacier melting globally,a process accompanied by the formation of substantial glacier *** phenomenon emerges as a pivotal area of study,especially in the Tibetan Plateau(TP),known as the Third Pole and the Asian Water *** particular,the rapid retreat of temperate glaciers in the southeastern TP has led to the formation of expansive glacier *** forelands are not merely evidence of climate shifts but are also key areas for transformative carbon ***,the newly exposed land surface actively adjusts the balance of dissolved organic carbon,especially in meltwater,and influences the release of greenhouse gases from a range of sources including glacial lakes,subglacial sediments,and supraglacial/proglacial *** processes play a crucial role in the dynamics of atmospheric carbon *** from our intensive and detailed observations over several years,this perspective not only emphasizes the importance of the underexplored impact of glacier forelands on carbon cycles but also opens a window into understanding potential future trajectories in a warming world.

关键词： Glacier Climate warming Carbon release Tibetan Plateau

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