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Productivity in the Southern Ocean Antarctic Zone during the Northern Hemisphere Glaciation(NHG)and its link to atmospheric pCO_(2)

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Science China Earth Sciences 2024年第7期67卷 2242-2252页

作者： Yiming WU Jingteng GUO Xiangyu ZHAO Wenshen XIAO Heng LIU Zhifang XIONG Tiegang LI Key Laboratory of Marine geology and Metallogeny First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory for Marine geology Laoshan LaboratoryQingdao 266237China School of Oceanography Shanghai Jiao Tong UniversityShanghai 200030China Key Laboratoryof Polar Ecosystem and Climate Change Shanghai Jiao Tong UniversityMinistry of EducationShanghai 200030China State Key Laboratory of Marine geology Tongji UniversityShanghai 200092China

A decrease in atmospheric CO_(2)partial pressure(pCO_(2))is considered an important prerequisite for the onset and intensification of Northern Hemisphere Glaciation(NHG).However,how the ocean sequestered missing CO_(2)during the NHG is still *** in surface productivity and deep ventilation in the Southern Ocean(SO)have been proposed to explain the variations in atmospheric pCO_(2)over the last eight glacial cycles,but it is unclear whether these mechanisms contributed to the decrease in atmospheric pCO_(2)during the *** titanium-normalized contents and mass accumulation rates of biogenic opal and total organic carbon from the International Ocean Discovery Program(IODP)Expedition 374 Site U1524A,we reconstruct the productivity in the Ross Sea,Antarctica,from 3.3 Ma to 2.4 *** productivity records exhibit a long-term decreasing trend and several distinct phased evolutionary ***,the local productivity fluctuated dramatically during 3.3-3.0 Ma,decreased gradually during 3.0-2.6 Ma,and remained relatively constant during 2.6-2.4 *** comparing productivity with its potential influences,we infer that the phased and long-term evolutions of productivity were mainly controlled by changes in deep ocean *** ice expansion might have decreased productivity during 3.3-3.0 Ma by light *** in eolian dust input have little effect on *** analysis revealed no coupling linkage between productivity and atmospheric pCO_(2),indicating that the productivity in the SO Antarctic Zone(AZ)was not the main factor controlling the atmospheric CO_(2)decrease during the *** improve our understanding of the role of SO processes in the NHG,further studies should focus on the potential influences of deep ocean ventilation on atmospheric pCO_(2)in the AZ,and similar studies should also be extended to the sea area in the Subantarctic Zone.

关键词： Ross Sea Biogenic opal Total organic carbon Deep ocean ventilation Sea ice Ocean carbon cycle

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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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Jurassic integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

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Science China Earth Sciences 2024年第4期67卷 1195-1228页

作者： Jianguo LI Xin RAO Lin MU Xiaohui CUI Xin LI Hui LUO Peixue LIU Center for Excellence in Life and Paleoenvironment Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China Nanjing College University of Chinese Academy of SciencesNanjing 211135China

The Qinghai-Tibetan Plateau experienced a unique geological evolution during the Jurassic,driven by the termination of the Palaeotethys and the reduction of the *** Indian Plate separated from the northern margin of Gondwana and drifted northward from the Southern *** that the timing of strata serves as the basis for reconstructing geological history,the present work aimed to develop a new multiple stratigraphic and chronologic framework for the Jurassic strata of the Qinghai-Tibetan Plateau region via a synthesis of the material on lithostratigraphy,palaeontology,iso-radiometric dating,magnetostratigraphy,and other techniques with an emphasis on recent progress and *** new framework included the Jurassic System from the four major subdivisions of the plateau:the Baryan Har,Qiangtang,Lhasa-Gandise,and Southern Xizang(Himalaya).Ultimately,a more complete,refined biostratigraphic sequence was proposed,comprising the most common fossils in the plateau and those that are stratigraphically significant for the Jurassic stratigraphy,including ammonites,bivalves,brachiopods,foraminifera,radiolarians,and dinoflagellate cysts for the marine strata,and pollen and spores,and charophytes for the terrestrial *** biostratigraphic framework was correlated with the Jurassic international standard zonation of the Geological Time Scale 2020 via standard or representative species or genera of *** on this framework,we constructed a lateral correlation of the Jurassic strata between different basins of the *** palaeontologic correlation in the present work shows that the Lhasa-Gandise Block had a closer relationship with the Qiangtang Block than with the Southern Xizang Himalaya during the Jurassic ***,the Lhasa-Gandise Block and Qiangtang Block shared similar marine fauna features of the north marginal East *** contrasts the opinion suggesting that the Yarlung Zangbo Tethys was a small back-arc basin.A c

关键词： Biostratigraphy Chronostratigraphy Correlation Yarlung Zangbo suture Bangong Co-Nujiang suture Tethys

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Lithium isotopic fractionation in minerals from pegmatites: Perspective of crystal chemistry

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Journal of Earth Science 2024年

作者： Shan-Ke Liu Ben-xun Su Key Laboratory of Mineral Resources， institute of geology and Geophysics， Chinese Academy of Sciences

Lack of information regarding lithium (Li) crystal chemistry in numerous minerals， especially those containing trace amounts of Li (ranging from few to tens of ppm)， limits our understanding of Li isotopic fractionation in pegmatites. In this study， we examined the Li isotopic composition and Li content in various Li-poor (e.g.， quartz or feldspar) together with Li-rich (sopdumene or lepidolite) mineral phases within granitic pegmatites. We compiled a comprehensive dataset， encompassing a broad spectrum of Li contents (ranging from a few to tens of thousands of ppm) and Li isotopic values (-8‰ to 41‰). The minerals exhibited distinct Li isotopic signatures. Specifically， elbaite and beryl showed the highest values， while biotite displayed a negative average. Compared to individual minerals， whole rocks demonstrated lower Li isotopic values， with pegmatites exhibiting the highest and non-granitic pegmatite wall rocks showing the lowest. Our study also uncovered a clear "V" shape relationship between Li isotopic values and logarithm of Li content， with different mineral groups occupying specific regions within this shape. Furthermore， a significant correlation was observed between average Li isotopic values and Li-O(OH， F) bond lengths in various minerals. These discoveries underscore the crucial role of crystal chemistry in shaping the Li isotopic behavior in pegmatites from a statistical perspective.

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Phanerozoic Tectonic Evolution,Metallogenesis and Formation of Mineral Systems in China

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 819-842页

作者： CHEN Xuanhua HAN Lele DING Weicui XU Shenglin TONG Ying ZHANG Yiping LI Bing ZHOU Qi WANG Ye SinoProbe Laboratory Chinese Academy of Geological SciencesBeijing 100037China institute of geology Chinese Academy of Geological SciencesBeijing 100037China

The continental Asia is mainly composed of three major tectonic regimes,the Tethys,Paleo Asian Ocean,and West *** underwent multi-stage plate convergences,ocean-continent transformations,and subductions,collisions and/or collages,and post collisional(orogenic)extensions in *** evolution of the Asia brings up a unique fault system and tectonic geomorphological features in the China's ***,it provides a geodynamic background for the formation and evolution of metallogeneses and mineral systems,resulting in nonuniform distribution of tectono-metallogenic systems and metallogenic *** spatiotemporal distribution of mineral deposits in China and adjacent areas exhibits periodic variation under controlling of the full life Wilson cycle and tectonic evolution,forming the plate convergence-related mineral system in East *** Cu deposits are mainly related to compressional systems in Paleozoic and early Mesozoic,and more closely related to post-collision extensional settings in late Mesozoic and *** Au deposits mainly formed in post-orogeny extensional *** rock related rare earth element deposits formed mainly at margins of the North China and Yangtze ***-pegmatite Li and other rare metal deposits formed mainly in early Mesozoic,related to Indosinian post-orogeny ***-metallogenic systems provide important basis for the prospecting of mineral resources.

关键词： tectonic evolution geodynamic system post-orogenic extension metallogenesis tectono-metallogenic system East Asia

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Identifying and localizing of seismogenic electromagnetic anomalies from data observed by permanent MT stations

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Science China Earth Sciences 2024年第5期67卷 1698-1713页

作者： Bing HAN Wenbao HU Guoze ZHAO Ji TANG State Key Laboratory of Earthquake Dynamics Institute of GeologyBeijing 100029China Key Laboratory of Exploration Technologies for Oil and Gas Resources of Ministry of Education Yangtze UniversityWuhan 430100China

In this research, an arbitrarily oriented electric dipole at subsurface is used to simulate Seismogenic Electromagnetic(SEM) radiation emanating from a seismic zone during its gestation phase. Analytical synthesis of responses at the Lijiang magnetotelluric(MT) station has revealed that SEM radiation could induce identifiable anomalies in the electromagnetic(EM)spectrum, apparent resistivity and phase within specific frequency bands. Background variations were extracted from long-term observation data of Dali and Lijiang MT stations, enabling the identification of SEM anomalies related to the Yunlong and Yangbi earthquakes. Multiple parameters of dipole sources at subsurface were obtained by applying the Differential Ant Colony Optimization(DACO) algorithm to anomalous data of two stations with multi-frequencies and various response functions. The spatial distribution of these predicted dipoles is predominantly clustered in or around the seismogenic area, with their azimuthal orientation aligning towards the seismogenic fault in general. This study has demonstrated the potential of using subsurface electric dipole simulations for SEM radiation analysis, offering a feasible approach for the prediction and understanding of seismogenic zones.

关键词： MT responses Identifying SEM anomaly Vector electric dipole responses Localizing SEM sources by inversion

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Provenance of colorless and brown volcanic glass in late Pleistocene tephra layers in the Western Philippine Sea

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Journal of Oceanology and Limnology 2024年第5期42卷 1438-1449页

作者： Fuqing JIANG Zhishun ZHANG Zhaohui ZHANG Guoliang ZHANG Peng HUANG Xiaojing ZHOU Zhifang XIONG Congying LI Tiegang LI Key Laboratory of Ocean Observation and Forecasting and Key Laboratory of Marine geology and Environment Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine geology Qingdao Marine Science and Technology CenterQingdao 266237China University of Chinese Academy of Sciences Beijing 100049China institute of Marine Chemistry and Environment Ocean CollegeZhejiang UniversityZhoushan 316021China College of Marine Technology and Environment Dalian Ocean UniversityDalian 116023China Key Laboratory of Marine Sedimentology and Environmental geology First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China

Tephra layers in the western Philippine Sea,characterized by abundant volcanic glass shards,may provide crucial evidence on the eruption history of volcanoes and tectonic evolution of the western Pacific.A 220-ka sediment core from the Benham Rise in the western Philippine Sea offers new insights into the provenance of four intercalated tephra layers(T1–T4,in chronological order)containing either colorless or brown glass *** to primitive mantle,all glass shards are enriched in large-ion lithophile elements,such as Rb,Cs,and Pb,and depleted in high field-strength elements,such as Th,Nb,and Ta,indicating a subduction-related *** colorless glass shards are characterized by high SiO_(2)(>78%)and light rare earth element(LREE)contents as well as high La/Sm ratios(>9),low FeO and MgO contents(100),pointing to a rhyolitic composition and a medium-K calc-alkaline serial *** contrast,the brown glass shards are characterized by lower SiO_(2)(<63%)and LREE contents,higher FeO,MgO,and CaO contents,lower La/Sm(<6)and Ba/Th(<75),and similar Sr/Y ratios(<15),indicating derivation from medium to high-K calc-alkaline andesite *** glass shards from layers T3(152 ka)and T4(172 ka)were correlated with volcanic deposits from the Taal and Laguna Caldera in the Maccolod Corridor,respectively,while the colorless glass shards from layers T1(36.5 ka)and T2(61.2 ka)were likely sourced from the Irosin Caldera in the Bicol *** the provenance of late Pleistocene tephra layers in the western Philippine Sea is helpful to complement a Philippine volcanic history and establish a regional tephrochronostratigraphy.

关键词： volcanic glass provenance chemical composition Philippine Sea late Pleistocene

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Respiratory protein-driven selectivity during the Permian-Triassic mass extinction

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The Innovation 2024年第3期5卷 122-128页

作者： Haijun Song Yuyang Wu Xu Dai Jacopo Dal Corso Fengyu Wang Yan Feng Daoliang Chu Li Tian Huyue Song William JFoster State Key Laboratory of Biogeology and Environmental geology School of Earth SciencesChina University of GeosciencesWuhan 430074China Biogéosciences UMR 6282CNRSUniversitéde Bourgogne21000 DijonFrance Universitat Hamburg Institute for Geology20148 HamburgGermany

Extinction selectivity determines the direction of macroevolution,especially during mass extinction;however,its driving mechanisms remain poorly *** investigating the physiological selectivity of marine animals during the Permian-Triassic mass extinction,we found that marine clades with lower O2-carrying capacity hemerythrin proteins and those relying on O2 diffusion experienced significantly greater extinction intensity and body-size reduction than those with higher O2-carrying capacity hemoglobin or hemocyanin *** findings suggest that animals with high O2-carrying capacity obtained the necessary O2 even under hypoxia and compensated for the increased energy requirements caused by ocean acidification,which enabled their survival during the Permian-Triassic mass ***,high O2-carrying capacity may have been crucial for the transition from the Paleozoic to the Modern Evolutionary Fauna.

关键词： extinction selectivity finding

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An Overview on the Composition and Age of Upper Crust of Proto-Tethyan Lajishan Intra-oceanic Arc,NE Tibet Plateau

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 285-302页

作者： FU Changlei HE Xiaohu YAN Zhen Jonathan CAITCHISON XIAO Wenjiao WANG Bingzhang LI Wufu LI Yusen SinoProbe Laboratory Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China Key Laboratory of the Northern Qinghai–Tibet Plateau Geological Processes and Mineral Resources Qinghai Geological Survey InstituteXining 810012China Department of geology School of Earth SciencesYunnan UniversityKunming 650091China School of Earth and Environmental Sciences University of QueenslandBrisbane 4072Australia Xinjiang institute of Ecology and Geography Chinese Academy of SciencesUrumqi 830011China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China School of Earth Science and Resources China University of GeosciencesBeijing 100083China

Identification and anatomy of oceanic arcs within ancient orogenic belt are significant for better understanding the tectonic framework and closure process of paleo-ocean *** article summarizes the geological,geochemical,and geochronological characteristics of upper crust of Proto-Tethyan Lajishan intra-oceanic arc and provides new data to constrain the subduction evolution of the South Qilian *** intra-oceanic arc volcanic rocks,including intermediate-mafic lava,breccia,tuff,and minor felsic rocks,are distributed along southern part of the Lajishan ophiolite *** and isotopic compositions indicate that the intermediate-mafic lava were originated from depleted mantle contaminated by sediment melts or hydrous fluids,whereas the felsic rocks were likely generated by partial melting of juvenile mafic crust in intra-oceanic arc *** from felsic rocks yield consistent and concordant ages ranging from 506 to 523 Ma,suggesting these volcanic rocks represent the relicts of upper crust of the Cambrian intra-oceanic *** with the Cambrian forearc ophiolite and accretionary complex,we suggest that the Cambrian intra-oceanic arc in the Lajishan ophiolite belt is belonging to the intra-oceanic arc system which was generated by south-directed subduction in the South Qilian Ocean at a relatively short interval between approximately 530 and 480 Ma.

关键词： volcanic rocks intra-oceanic arc U-Pb age Lajishan ophiolite belt South Qilian Ocean Proto-Tethyan realm

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An adaptive finite-difference method for seismic traveltime modeling based on 3D eikonal equation

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Petroleum Science 2024年第1期21卷 195-205页

作者： Bao-Ping Qiao Qing-Qing Li Wei-Guang He Dan Zhao Qu-Bo Wu CNNC Beijing Research institute of Uranium geology Beijing 100029China National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao 266580ShangdongChina SINOPEC Geophysical Research institute Nanjing211103JiangsuChina

3D eikonal equation is a partial differential equation for the calculation of first-arrival traveltimes and has been widely applied in many scopes such as ray tracing,source localization,reflection migration,seismic monitoring and tomographic *** recent years,many advanced methods have been developed to solve the 3D eikonal equation in heterogeneous ***,there are still challenges for the stable and accurate calculation of first-arrival traveltimes in 3D strongly inhomogeneous *** this paper,we propose an adaptive finite-difference(AFD)method to numerically solve the 3D eikonal *** novel method makes full use of the advantages of different local operators characterizing different seismic wave types to calculate factors and traveltimes,and then the most accurate factor and traveltime are adaptively selected for the convergent updating based on the Fermat *** with global fast sweeping describing seismic waves propagating along eight directions in 3D media,our novel method can achieve the robust calculation of first-arrival traveltimes with high precision at grid points either near source point or far away from source point even in a velocity model with large and sharp *** numerical examples show the good performance of the AFD method,which will be beneficial to many scientific applications.

关键词： 3D eikonal equation Accurate traveltimes Global fast sweeping 3D inhomogeneous media Adaptive finite-difference method

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