From lecture halls in Beijing to villages in the mountains of southwest China,a group of young rural innovators from Global South countries recently embarked on a journey that connected policy thinking,technological p...From lecture halls in Beijing to villages in the mountains of southwest China,a group of young rural innovators from Global South countries recently embarked on a journey that connected policy thinking,technological practice and lived rural experience.展开更多
Cirrus clouds play a crucial role in the energy balance of the Earth-atmosphere system.We investigated the spatiotemporal variations of cirrus over the South China Sea(SCS)using satellite data(MOD08,MYD08,CALIPSO)and ...Cirrus clouds play a crucial role in the energy balance of the Earth-atmosphere system.We investigated the spatiotemporal variations of cirrus over the South China Sea(SCS)using satellite data(MOD08,MYD08,CALIPSO)and reanalysis data(MERRA-2)from March 2007 to February 2015(eight years).The horizontal distribution reveals lower cirrus fraction values in the northern SCS and higher values in the southern region,with minima observed in March and April and maxima sequentially occurring in August(northern SCS,NSCS),September(middle SCS,MSCS),and December(southern SCS,SSCS).Vertically,the cirrus fraction peaks in summer and reaches its lowest levels in spring.Opaque cirrus dominates during summer in the NSCS and MSCS,comprising 53.6%and 55.9%,respectively,while the SSCS exhibits a higher frequency of opaque cirrus relative to other cloud types.Subvisible cirrus clouds have the lowest frequency year-round,whereas thin cirrus is most prominent in winter in the NSCS(46.3%)and in spring in the MSCS(45.3%).A case study from September 2021 further explores the influence of ice crystal habits on brightness temperature(BT)over the SCS.Simulations utilizing five ice crystal shapes from the ARTS DDA(Atmospheric Radiative Transfer Simulator Discrete Dipole Approximation)database and the RTTOV 12.4 radiative transfer model reveal that the 8-column-aggregate shape best represents BT in the NSCS and SSCS,while the large-block-aggregate shape performs better in the SSCS.展开更多
High-Mg andesites(HMAs)typically originate in subduction-related tectonic settings,including active continental margins and island arcs,and studies of HMAs can constrain the tectonic evolution of the South China Block...High-Mg andesites(HMAs)typically originate in subduction-related tectonic settings,including active continental margins and island arcs,and studies of HMAs can constrain the tectonic evolution of the South China Block and Paleo-Tethyan Ocean.This paper presents new chronological and geochemical data for high-Mg gabbroic diorites in the Funing area,southern South China.The gabbroic diorites yield ages of 254-249 Ma,and have moderate SiO2 contents(51.3%-57.8%),high MgO contents(4.6%-10.2%)and Mg^(#)values(52-75),enrichment in large-ion lithophile elements and light rare earth elements,and depletion in high-field-strength elements-collectively displaying geochemical signatures typical of sanukites.The gabbroic diorites have radiogenic initial Sr and Pb isotopic compositions,and negativeεNd(t)andεHf(t)values.These characteristics distinguish the Funing gabbroic diorites from subduction-related igneous rocks in the Paleo-Pacific tectonic domain.Instead,they are isotopically similar to HMAs and basalts along the Paleo-Tethys suture.We propose the high-Mg gabbroic diorites and basaltic andesites in Funing area share a common mantle source,linked to subduction and rollback of the Paleo-Tethyan plate beneath the South China Block,which triggered back-arc rifting and partial melting of the metasomatized lithospheric mantle during the Late Permian to Early Triassic.展开更多
Background In July 2024,the European Union's Ecodesign for Sustainable Products Regulation,or ESPR,officially came into effect.This regulation mandates that products entering the EU market must use a Digital Produ...Background In July 2024,the European Union's Ecodesign for Sustainable Products Regulation,or ESPR,officially came into effect.This regulation mandates that products entering the EU market must use a Digital Product Passport,known as DPP,to disclose their compliance certifications,environmental impact,and supply chain information.Failure to comply may result in exclusion from the EU market.展开更多
The prediction of sea surface partial pressure of carbon dioxide(pCO_(2))in the South China Sea is crucial for understanding the region’s contribution to the global carbon budget and its interactions with climate cha...The prediction of sea surface partial pressure of carbon dioxide(pCO_(2))in the South China Sea is crucial for understanding the region’s contribution to the global carbon budget and its interactions with climate change.We applied the Spatiotemporal Convolutional Long Short-Term Memory(STConvLSTM)model,integrating key environmental factors including sea surface temperature(SST),sea surface salinity(SSS),and chlorophyll a(Chl a),to predict and analyze sea surface pCO_(2)in the South China Sea.The model demonstrated high accuracy in short-term predictions(1 month),with a mean absolute error(MAE)of 0.394,a root mean square error(RMSE)of 0.659,and a coefficient of determination(R^(2))of 0.998.For long-term predictions(12 months),the model maintained its predictive capability,with an MAE of 0.667,RMSE of 1.255,and R^(2)of 0.994.Feature importance analysis revealed that sea surface pCO_(2)and SST were the main drivers of the model’s predictions,whereas Chl a and SSS had relatively minor impacts.The model’s generalization ability was further validated in the northwest Pacific Ocean and tropical Pacific Ocean,where it successfully captured the spatiotemporal variation in pCO_(2)with small prediction errors.The ST-ConvLSTM model provides an efficient and accurate tool for forecasting and analyzing sea surface pCO_(2)in the South China Sea,offering new insights into global carbon cycling and climate change.This study demonstrates the potential of deep learning in marine science and provides a significant technical support for global changes and marine ecosystem research.展开更多
The Shenshan Group provides important geological information which is vital in unraveling the amalgamation and subsequent rifting processes of South China.While conventional studies have asserted its formation in a su...The Shenshan Group provides important geological information which is vital in unraveling the amalgamation and subsequent rifting processes of South China.While conventional studies have asserted its formation in a subduction setting,the distinct investigation reveals the necessity for reassessment.To address this,the authors employ integrated methods encompassing petrological,zircon U-Pb geochronological,Lu-Hf isotopic and geochemical methods for sedimentary rocks from the upper Shenshan subgroup and Banxi Group.The geochemical results indicate that they were formed through the recycling deposition of intermediate-acidic igneous source material and experienced moderate chemical weathering.Additionally,both sedimentary sequences exhibit characteristics consistent with those formed in an intracontinental extensional rift setting since ca.810 Ma.The provenance analysis indicates that the upper Shenshan subgroup primarily originates from the Yangtze Domain,while the Banxi Group from both the Yangtze and Cathaysia domains.Synthesizing with previous studies,the Shenshan Group should be subdivided into the lower and upper subgroups which represent distinct tectonic backgrounds.The lower subgroup is inferred to have formed in an Early Neoproterozoic fore-arc setting,akin to the Zhoutan group.The upper subgroup corresponds to the Banxi Group,representing the Middle Neoproterozoic postorogenic rift setting,responding to the breakup of Rodinia.展开更多
Southerly moisture surges over the central South China Sea(SCS)are characterized by the strengthening of lowlevel southerlies that transport moisture northward from the Pacific or Indian Oceans to South China.These su...Southerly moisture surges over the central South China Sea(SCS)are characterized by the strengthening of lowlevel southerlies that transport moisture northward from the Pacific or Indian Oceans to South China.These surge events typically occur for days in the early-summer season(from April to June)and can lead to heavy rains in South China.This study categorizes surge events into three types of flow patterns and examines their multiscale variations and impacts on rainfall.The first type occurs mainly in April,with the southeasterlies enhanced by a deepening trough in South China and the western Pacific subtropical high established over the SCS.The second type of surge events mostly appears in June,featuring the prevailing southwesterlies of summer monsoon from the Indian Ocean during the active phases of intraseasonal oscillations.Most surge events exhibit semi-diurnal variations with morning and afternoon peaks of northward moisture fluxes.Specifically,the first type features a dominant afternoon peak,while the second type shows a dominant early-morning peak,which is induced by thermal contrast between the Indochina Peninsula and the SCS.In general,the surge events enhance moisture convergence and increase rainfall downstream in South China,but they show some regional differences.The second type strengthens moisture convergence and rainfall in coastal regions with a morning peak.In contrast,the first type enhances inland rainfall with a morning peak,while moisture divergence dominates coastal regions.The third type of surge events denotes transitional conditions between the first two types,in terms of atmospheric circulations,diurnal cycles,and rainfall patterns.These results highlight a diversity of regional moisture surges and related rainfall ranging from diurnal to sub-seasonal scales.展开更多
Amid overlapping crises and uncertainties as the world enters an era of turbulence and transformation,the countries of the Global South are swiftly emerging from the periphery of world politics to the forefront of int...Amid overlapping crises and uncertainties as the world enters an era of turbulence and transformation,the countries of the Global South are swiftly emerging from the periphery of world politics to the forefront of international cooperation,playing an increasingly vital role in advancing humanity’s collective progress.展开更多
South African scholars highlight the importance of Xi Jinping:The Governance of China China is playing an increasingly active and important role in global politics and economy,especially in the development of the Glob...South African scholars highlight the importance of Xi Jinping:The Governance of China China is playing an increasingly active and important role in global politics and economy,especially in the development of the Global South.展开更多
This study explores the impact of winter sea surface temperature(SST)anomalies in the Southern Indian Ocean on summer precipitation patterns in China,utilizing data from reanalysis sources and Coupled Model Intercompa...This study explores the impact of winter sea surface temperature(SST)anomalies in the Southern Indian Ocean on summer precipitation patterns in China,utilizing data from reanalysis sources and Coupled Model Intercomparison Project Phase 6(CMIP6)models.The results reveal that the Southern Indian Ocean Dipole(SIOD),characterized by contrasting SST anomalies in the northeast and southwest regions,acts as a predictor for Chinese summer precipitation patterns,namely floods in the south and drought in the north.In a positive SIOD event,the southwestern Indian Ocean exhibits warmer SSTs,while the northeastern region remains cooler.A negative SIOD event shows the opposite pattern.During the positive phase of the SIOD,the winter SST distribution strengthens the 850-hPa cross-equatorial airflow,generating a robust low-level westerly jet that enhances water vapor transport to the Bay of Bengal(BoB).These air-sea interactions maintain lower SSTs in the northeastern region,which significantly increase the land-sea temperature contrast in the Northern Hemisphere during spring and summer.This strengthened thermal gradient intensifies the southwest monsoon,establishing a strong convergence zone near the South China Sea and amplifying monsoon-driven precipitation in South China.Additionally,CMIP6 models,such as NorESM2-LM and NorCPM1,which accurately simulate the SIOD pattern,effectively capture the seasonal response of cross-equatorial airflow driven by SST anomalies of Southern Indian Ocean.The result highlights the essential role of cross-equatorial airflow generated by the SIOD in forecasting crossseasonal precipitation patterns.展开更多
Global South,representing the collective of emerging markets and developing countries,is becoming a pivotal force in reshaping the international order.It plays a vital role in driving global governance reforms with th...Global South,representing the collective of emerging markets and developing countries,is becoming a pivotal force in reshaping the international order.It plays a vital role in driving global governance reforms with the principle of fairness and equity.展开更多
The ocean heat content variability in the South China Sea(SCS)plays a pivotal role in regional climate and extreme weather events,such as tropical cyclones.Using high-resolution ocean reanalysis data,we show that the ...The ocean heat content variability in the South China Sea(SCS)plays a pivotal role in regional climate and extreme weather events,such as tropical cyclones.Using high-resolution ocean reanalysis data,we show that the SCS exhibits a summer subsurface temperature dipole mode that controls the interannual variability of ocean heat content in the upper SCS.This dipole mode manifests as warm anomalies in the north and cold anomalies in the south during strong monsoon years,and a reversed pattern during weak monsoons years.The monsoon variability is linked to large-scale climate variability associated with El Niño-Southern Oscillation transitions.Heat budget analysis indicates that this dipole pattern is primarily driven by vertical heat transport linked to opposite wind stress curl anomalies in the northern and southern basin.Accompanying the vertical heat transports is a shallow meridional overturning circulation that redistributes heat between the northern and southern SCS.展开更多
The Late Cretaceous Jiepailing granitoids,located at the central Nanling Range in South China,are closely associated with significant Sn-Li-Be-F polymetallic metallogeny.The Jiepailing granitoids mainly consist of gra...The Late Cretaceous Jiepailing granitoids,located at the central Nanling Range in South China,are closely associated with significant Sn-Li-Be-F polymetallic metallogeny.The Jiepailing granitoids mainly consist of granitic porphyry and zinnwaldite granite.The two granitoids have an A-type affinity,showing elevated Rb/Sr ratios and significant depletions in Ba,Sr and P.Integrated zircon and monazite U-Pb dating results suggest that granitic porphyry and zinnwaldite granite were emplaced at~89 Ma and~94 Ma,respectively.The low Ce^(4+)/Ce^(3+)ratios of the Jiepailing granitoids,together with significant negative Eu anomalies of the zircons,indicate that their formation occurred under conditions of reduced oxygen fugacity.Through the analysis of zircon Hf-O and whole-rock Nd isotopes,it has been determined that both stages of the Jiepailing granitoids originated in the lower-middle Mesoproterozoic crustal basement[ε_(Nd)(t)=−5.33 to−4.96,t^(C)_(DM)(Nd)=1289-1234 Ma,ε_(Hf)(t)=−4.13 to+2.22,t^(C)_(DM)(Hf)=1418-1015 Ma andδ^(18)O_(Zrc)=6.33‰-7.72‰],with the involvement of mantle-derived materials.Both granitic porphyry and zinnwaldite granite exhibit elevated concentrations of fluorine(F),with the positive correlation between F and Sn emphasizing the crucial role of high F sources in tin mineralization.Drawing upon the study of the Late Cretaceous magma systems in southern Hunan and through comparison with the mineralized granites observed in coastal regions during the Late Cretaceous,a genetic model for the mineralized granites in the Nanling region is developed.When the Paleo-Pacific Plate retreated to the coastal region,the continental crust in southern China underwent extensional thinning and asthenospheric upwelling due to gravitational collapse.Such processes resulted in the partial melting of the middle-lower crustal metamorphic sedimentary basement and the subsequent formation of F-rich granitic magmas,related to tin mineralization.展开更多
The petrogenesis and genetic link to polymetallic mineralization of the granites in the Dayishan complex,southern Hunan province remain debated.Here,we present an integrated study on the petrology,zircon U-Pb ages and...The petrogenesis and genetic link to polymetallic mineralization of the granites in the Dayishan complex,southern Hunan province remain debated.Here,we present an integrated study on the petrology,zircon U-Pb ages and whole-rock geochemistry for this complex.Our findings indicate that the southern complex consists of(amphibole-bearing)biotite granites and muscovite granites emplaced at 153-151 Ma,and the central and northern complex consists of two-mica granites and tourmaline-bearing muscovite granites,respectively with the former emplaced at 164 Ma and the latter at 150 Ma.The(amphibole-bearing)biotite granites have SiO_(2) contents of 68.0-73.8 wt% and are enriched in alkalis and rare earth elements and depleted in Sr and Ba.They display Zr+Y+Ce+Nb>350 ppm and 10000×Ga/Al>2.6 along with high zircon saturation temperatures(821-883oC).The two-mica granites and(tourmaline-bearing)muscovite granites have high SiO_(2)(74.4-77.3 wt%)and low Ga/Al,Zr+Nb+Ce+Y,K/Rb,Zr/Hf,and Nb/Ta along with low zircon saturation temperatures(709-817℃).Geochemical characteristics suggest that the(amphibole-bearing)biotite granites are A-type granites generated through shallow dehydration melting of early Paleozoic granitoids,and that the two-mica granites and(tourmaline-bearing)muscovite granites are fractionated A-type granites produced through fractionation crystallization from the(amphibole-bearing)biotite granites accompanied by fluid fractionation.展开更多
The relation between conflict and governance has been dominated by type of government rather than by system of government.With increasing conflict in countries with ethnic and religious diversity,the debate has gradua...The relation between conflict and governance has been dominated by type of government rather than by system of government.With increasing conflict in countries with ethnic and religious diversity,the debate has gradually shifted to understand better the link between conflict and system of government.There is a growing evidence that suggests federal system performs better than unitary system in managing diversity and reducing conflict.Decentralization is even seen to be more effective than federal system not only in managing diversity and reducing conflict but also in delivering public goods.This article provides an account of evolution of system of government in South Sudan.It finds a clear association of centralized unitary system with violent conflict and a relative peace during period of decentralized government or federal system.A decentralized federal system may be appropriate for South Sudan in managing diversity and mitigating conflict.Despite the popular demand by their citizens for a federal system to manage diversity and reduce violent conflict,the ruling elites in the post-independent South Sudan adopted instead an autocratic centralized unitary system that contributed among other factors to the persistent violent conflicts,erosion of social cohesion,and rising mistrust between state and citizens and between and among the communities of South Sudan.展开更多
There is a growing recognition of the critical role of security governance in advancing democratic transition in the post-conflict environment.Despite such a recognition,the security sector reform concept has overshad...There is a growing recognition of the critical role of security governance in advancing democratic transition in the post-conflict environment.Despite such a recognition,the security sector reform concept has overshadowed the importance of the overarching strategic role of security governance in transition to democracy,particularly in Africa.This paper assesses the status and challenges facing security governance and how they thwarted the efforts to furthering the democratic transition in South Sudan.The paper shows a deterioration in security,safety and security governance outcomes since the independence of South Sudan in 2011 with such a trend unlikely to be abated in the near future without strategic interventions.Some of the challenges facing security governance in South Sudan include the legacies of some historical events including the“Big Tent Policy”,absence of strategic leadership,lack of overarching policy framework,impractical and tenuous security arrangements in the 2018 peace agreement,persistent postponement of the first elections,and dysfunctional justice sector.The paper provides some strategic and operational recommendations to improve security governance and advance democratic transition in South Sudan.These recommendations include formulation of an inclusive and people-centered national security policy,rigorous judicial reform,and early political agreement on new political infrastructure if conditions for holding the first national elections are not met in 2026.展开更多
Both fractional crystallization and fluid-melt-crystal interaction are involved in the formation of highly fractionated granites.This paper assessed those two processes using geochemistry of muscovite and tourmaline a...Both fractional crystallization and fluid-melt-crystal interaction are involved in the formation of highly fractionated granites.This paper assessed those two processes using geochemistry of muscovite and tourmaline and bulkrock chemistry of multi-phase Wangxianling granitoids,South China.Compositional variations suggest the coarse-grained muscovite granite is produced from fractional crystallization of the two-mica granite whereas the fine-grained muscovite granite represents a distinct magma pulse.Progressive fractionation of quartz,feldspar and biotite leads to elevated boron and aluminum content in melt which promoted muscovite and tourmaline to crystallize,which promotes two-mica granite evolving towards tourmaline-bearing muscovite granite.Fluid-melt-crystal interaction occurred at the magmatichydrothermal transitional stage and resulted in the textural and chemical zonings of tourmaline and muscovite in finegrained muscovite granite.The rims of both tourmaline and muscovite are characterized by the enrichment of fluid mobile elements such as Li,Mn,Cs and Zn and heavierδ^(11)B values of the tourmaline rims(-15.0‰to-13.6‰)compared to cores(-15.7‰to-14.3‰).Meanwhile,significant M-type REE tetrad effects(TE_(1,3)=1.07-1.18)and low K/Rb ratios(48-52)also correspond to fluid-melt-crystal interaction.This study shows zoned muscovite and tourmaline can be excellent tracers of fractional crystallization and late-stage fluid-melt-crystal interaction in highly evolved magmatic systems.展开更多
Deciphering high-pressure granulite-facies metamorphism and anatexis within a collisional orogeny can provide crucial constraints on geodynamic evolution and melt activity during subduction and exhumation.Combining pe...Deciphering high-pressure granulite-facies metamorphism and anatexis within a collisional orogeny can provide crucial constraints on geodynamic evolution and melt activity during subduction and exhumation.Combining petrographic observations,mineral chemistry,REE in Grt-Cpx thermobarometry,and previous work,at least four stages are suggested for the metamorphic evolution of the mafic granulites in the South Altun,including the protolith stage,the high-pressure granulite-facies stage(909-1037℃and 17.3-30 kbar),medium-pressure granulite-facies overprint(9.1-11.9 kbar and 753-816℃),and subsequent late amphibolite-greenschist-facies metamorphism.Zircon U-Pb dating shows that the mafic granulites underwent high-pressure granulite-facies metamorphism at 497.2±3.7 Ma,while the leucosome formed at 498.2±2.9 Ma.Thus,the leucosomes from the host mafic granulite may have been formed at the high-pressure granulite-facies metamorphic event.The characteristics of zircon morphology,mineral inclusions,low Th/U values,HREE enrichment,and negative Eu anomalies indicate that these zircons from the leucosome were formed from the metamorphic melts.The characteristics of whole-rock major and trace elements as well as Hf isotopic features of zircons between the leucosomes and the host mafic granulite indicate that the melt may have been generated by the partial melting of the host mafic granulite.展开更多
The Fushan Depression is one of the petroliferous depressions in the Beibuwan Basin,South China Sea.Previous studies have preliminarily explored the origin and source of crude oils in some areas of this depression.Nev...The Fushan Depression is one of the petroliferous depressions in the Beibuwan Basin,South China Sea.Previous studies have preliminarily explored the origin and source of crude oils in some areas of this depression.Nevertheless,no systematic investigations on the classification and origin of oils and hy-drocarbon migration processes have been made for the entire petroleum system in this depression,which has significantly hindered the hydrocarbon exploration in the region.A total of 32 mudstone and 58 oil samples from the Fushan Depression were analyzed to definite the detailed oil-source correlation within the sequence and sedimentary framework.The organic matter of third member of Paleogene Liushagang Formation(Els(3))source rocks,both deltaic and lacustrine mudstone,are algal-dominated with high abundance of C_(23)tricyclic terpane and C_(30)4-methylsteranes.The deltaic source rocks occur-ring in the first member(Els_(1))and second member(Els_(2))of the Paleogene Liushagang Formation are characterized by high abundance of C_(19+20)tricyclic terpane and oleanane,reflecting a more terrestrial plants contribution.While lacustrine source rocks of Els_(1)and Els_(2)display the reduced input of terrige-nous organic matter with relatively low abundance of C 19+20 tricyclic terpane and oleanane.Three types of oils were identified by their biomarker compositions in this study.Most of the oils discovered in the Huachang and Bailian Els_(1)reservoir belong to group A and were derived from lacustrine source rocks of Els_(1)and Els_(2).Group B oils are found within the Els_(1)and Els_(2)reservoirs,showing a close relation to the deltaic source rocks of Els_(1)and Els_(2),respectively.Group C oils,occurring in the Els3 reservoirs,have a good affinity with the Els3 source rocks.The spatial distribution and accumulation of different groups of oils are mainly controlled by the sedimentary facies and specific structural conditions.The Els_(2)reservoir in the Yong'an area belonging to Group B oil,are adjacent to the source kitchen and could be considered as the favorable exploration area in the future.展开更多
文摘From lecture halls in Beijing to villages in the mountains of southwest China,a group of young rural innovators from Global South countries recently embarked on a journey that connected policy thinking,technological practice and lived rural experience.
基金supported by the National Natural Science Foundation of China(Grant Nos.42027804,41775026,and 41075012)。
文摘Cirrus clouds play a crucial role in the energy balance of the Earth-atmosphere system.We investigated the spatiotemporal variations of cirrus over the South China Sea(SCS)using satellite data(MOD08,MYD08,CALIPSO)and reanalysis data(MERRA-2)from March 2007 to February 2015(eight years).The horizontal distribution reveals lower cirrus fraction values in the northern SCS and higher values in the southern region,with minima observed in March and April and maxima sequentially occurring in August(northern SCS,NSCS),September(middle SCS,MSCS),and December(southern SCS,SSCS).Vertically,the cirrus fraction peaks in summer and reaches its lowest levels in spring.Opaque cirrus dominates during summer in the NSCS and MSCS,comprising 53.6%and 55.9%,respectively,while the SSCS exhibits a higher frequency of opaque cirrus relative to other cloud types.Subvisible cirrus clouds have the lowest frequency year-round,whereas thin cirrus is most prominent in winter in the NSCS(46.3%)and in spring in the MSCS(45.3%).A case study from September 2021 further explores the influence of ice crystal habits on brightness temperature(BT)over the SCS.Simulations utilizing five ice crystal shapes from the ARTS DDA(Atmospheric Radiative Transfer Simulator Discrete Dipole Approximation)database and the RTTOV 12.4 radiative transfer model reveal that the 8-column-aggregate shape best represents BT in the NSCS and SSCS,while the large-block-aggregate shape performs better in the SSCS.
基金supported by the National Natural Science Foundation of China (42473063)Guike AD24010023, the Seventh Guangxi Zhuang Autonomous Region Bagui Scholars Program (to LIU Xijun)the Guangxi Natural Science Foundations of China (2025GXNSFBA069054)
文摘High-Mg andesites(HMAs)typically originate in subduction-related tectonic settings,including active continental margins and island arcs,and studies of HMAs can constrain the tectonic evolution of the South China Block and Paleo-Tethyan Ocean.This paper presents new chronological and geochemical data for high-Mg gabbroic diorites in the Funing area,southern South China.The gabbroic diorites yield ages of 254-249 Ma,and have moderate SiO2 contents(51.3%-57.8%),high MgO contents(4.6%-10.2%)and Mg^(#)values(52-75),enrichment in large-ion lithophile elements and light rare earth elements,and depletion in high-field-strength elements-collectively displaying geochemical signatures typical of sanukites.The gabbroic diorites have radiogenic initial Sr and Pb isotopic compositions,and negativeεNd(t)andεHf(t)values.These characteristics distinguish the Funing gabbroic diorites from subduction-related igneous rocks in the Paleo-Pacific tectonic domain.Instead,they are isotopically similar to HMAs and basalts along the Paleo-Tethys suture.We propose the high-Mg gabbroic diorites and basaltic andesites in Funing area share a common mantle source,linked to subduction and rollback of the Paleo-Tethyan plate beneath the South China Block,which triggered back-arc rifting and partial melting of the metasomatized lithospheric mantle during the Late Permian to Early Triassic.
文摘Background In July 2024,the European Union's Ecodesign for Sustainable Products Regulation,or ESPR,officially came into effect.This regulation mandates that products entering the EU market must use a Digital Product Passport,known as DPP,to disclose their compliance certifications,environmental impact,and supply chain information.Failure to comply may result in exclusion from the EU market.
基金Supported by the National Key Research and Development Program of China(No.2023YFC3008202)the National Natural Science Foundation of China(No.42406019)the Scientific Research Fund of Zhejiang Provincial Education Department(No.Y202353066)。
文摘The prediction of sea surface partial pressure of carbon dioxide(pCO_(2))in the South China Sea is crucial for understanding the region’s contribution to the global carbon budget and its interactions with climate change.We applied the Spatiotemporal Convolutional Long Short-Term Memory(STConvLSTM)model,integrating key environmental factors including sea surface temperature(SST),sea surface salinity(SSS),and chlorophyll a(Chl a),to predict and analyze sea surface pCO_(2)in the South China Sea.The model demonstrated high accuracy in short-term predictions(1 month),with a mean absolute error(MAE)of 0.394,a root mean square error(RMSE)of 0.659,and a coefficient of determination(R^(2))of 0.998.For long-term predictions(12 months),the model maintained its predictive capability,with an MAE of 0.667,RMSE of 1.255,and R^(2)of 0.994.Feature importance analysis revealed that sea surface pCO_(2)and SST were the main drivers of the model’s predictions,whereas Chl a and SSS had relatively minor impacts.The model’s generalization ability was further validated in the northwest Pacific Ocean and tropical Pacific Ocean,where it successfully captured the spatiotemporal variation in pCO_(2)with small prediction errors.The ST-ConvLSTM model provides an efficient and accurate tool for forecasting and analyzing sea surface pCO_(2)in the South China Sea,offering new insights into global carbon cycling and climate change.This study demonstrates the potential of deep learning in marine science and provides a significant technical support for global changes and marine ecosystem research.
基金supported by the National Natural Science Foundation of China(42372250,42102262 and 41972235)National Key Research and Development Program Project(2023YFF0803701)+1 种基金Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2023SP206)the program of China Scholarship Council。
文摘The Shenshan Group provides important geological information which is vital in unraveling the amalgamation and subsequent rifting processes of South China.While conventional studies have asserted its formation in a subduction setting,the distinct investigation reveals the necessity for reassessment.To address this,the authors employ integrated methods encompassing petrological,zircon U-Pb geochronological,Lu-Hf isotopic and geochemical methods for sedimentary rocks from the upper Shenshan subgroup and Banxi Group.The geochemical results indicate that they were formed through the recycling deposition of intermediate-acidic igneous source material and experienced moderate chemical weathering.Additionally,both sedimentary sequences exhibit characteristics consistent with those formed in an intracontinental extensional rift setting since ca.810 Ma.The provenance analysis indicates that the upper Shenshan subgroup primarily originates from the Yangtze Domain,while the Banxi Group from both the Yangtze and Cathaysia domains.Synthesizing with previous studies,the Shenshan Group should be subdivided into the lower and upper subgroups which represent distinct tectonic backgrounds.The lower subgroup is inferred to have formed in an Early Neoproterozoic fore-arc setting,akin to the Zhoutan group.The upper subgroup corresponds to the Banxi Group,representing the Middle Neoproterozoic postorogenic rift setting,responding to the breakup of Rodinia.
基金Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)National Natural Science Foundation of China(42475003)Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2023SP209)。
文摘Southerly moisture surges over the central South China Sea(SCS)are characterized by the strengthening of lowlevel southerlies that transport moisture northward from the Pacific or Indian Oceans to South China.These surge events typically occur for days in the early-summer season(from April to June)and can lead to heavy rains in South China.This study categorizes surge events into three types of flow patterns and examines their multiscale variations and impacts on rainfall.The first type occurs mainly in April,with the southeasterlies enhanced by a deepening trough in South China and the western Pacific subtropical high established over the SCS.The second type of surge events mostly appears in June,featuring the prevailing southwesterlies of summer monsoon from the Indian Ocean during the active phases of intraseasonal oscillations.Most surge events exhibit semi-diurnal variations with morning and afternoon peaks of northward moisture fluxes.Specifically,the first type features a dominant afternoon peak,while the second type shows a dominant early-morning peak,which is induced by thermal contrast between the Indochina Peninsula and the SCS.In general,the surge events enhance moisture convergence and increase rainfall downstream in South China,but they show some regional differences.The second type strengthens moisture convergence and rainfall in coastal regions with a morning peak.In contrast,the first type enhances inland rainfall with a morning peak,while moisture divergence dominates coastal regions.The third type of surge events denotes transitional conditions between the first two types,in terms of atmospheric circulations,diurnal cycles,and rainfall patterns.These results highlight a diversity of regional moisture surges and related rainfall ranging from diurnal to sub-seasonal scales.
文摘Amid overlapping crises and uncertainties as the world enters an era of turbulence and transformation,the countries of the Global South are swiftly emerging from the periphery of world politics to the forefront of international cooperation,playing an increasingly vital role in advancing humanity’s collective progress.
文摘South African scholars highlight the importance of Xi Jinping:The Governance of China China is playing an increasingly active and important role in global politics and economy,especially in the development of the Global South.
基金Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)National Natural Science Foundation of China(U2442202)+1 种基金Key Innovation Team of China Meteorological Administration“Climate Change Detection and Response”(CMA2022ZD03)National Key Research and Development Program of China(2023YFF0805104)。
文摘This study explores the impact of winter sea surface temperature(SST)anomalies in the Southern Indian Ocean on summer precipitation patterns in China,utilizing data from reanalysis sources and Coupled Model Intercomparison Project Phase 6(CMIP6)models.The results reveal that the Southern Indian Ocean Dipole(SIOD),characterized by contrasting SST anomalies in the northeast and southwest regions,acts as a predictor for Chinese summer precipitation patterns,namely floods in the south and drought in the north.In a positive SIOD event,the southwestern Indian Ocean exhibits warmer SSTs,while the northeastern region remains cooler.A negative SIOD event shows the opposite pattern.During the positive phase of the SIOD,the winter SST distribution strengthens the 850-hPa cross-equatorial airflow,generating a robust low-level westerly jet that enhances water vapor transport to the Bay of Bengal(BoB).These air-sea interactions maintain lower SSTs in the northeastern region,which significantly increase the land-sea temperature contrast in the Northern Hemisphere during spring and summer.This strengthened thermal gradient intensifies the southwest monsoon,establishing a strong convergence zone near the South China Sea and amplifying monsoon-driven precipitation in South China.Additionally,CMIP6 models,such as NorESM2-LM and NorCPM1,which accurately simulate the SIOD pattern,effectively capture the seasonal response of cross-equatorial airflow driven by SST anomalies of Southern Indian Ocean.The result highlights the essential role of cross-equatorial airflow generated by the SIOD in forecasting crossseasonal precipitation patterns.
文摘Global South,representing the collective of emerging markets and developing countries,is becoming a pivotal force in reshaping the international order.It plays a vital role in driving global governance reforms with the principle of fairness and equity.
基金The National Key R&D Program of under contract No.2024YFF0506603.
文摘The ocean heat content variability in the South China Sea(SCS)plays a pivotal role in regional climate and extreme weather events,such as tropical cyclones.Using high-resolution ocean reanalysis data,we show that the SCS exhibits a summer subsurface temperature dipole mode that controls the interannual variability of ocean heat content in the upper SCS.This dipole mode manifests as warm anomalies in the north and cold anomalies in the south during strong monsoon years,and a reversed pattern during weak monsoons years.The monsoon variability is linked to large-scale climate variability associated with El Niño-Southern Oscillation transitions.Heat budget analysis indicates that this dipole pattern is primarily driven by vertical heat transport linked to opposite wind stress curl anomalies in the northern and southern basin.Accompanying the vertical heat transports is a shallow meridional overturning circulation that redistributes heat between the northern and southern SCS.
基金financially supported by the National Natural Science Foundation of China(Grant No.42303073).
文摘The Late Cretaceous Jiepailing granitoids,located at the central Nanling Range in South China,are closely associated with significant Sn-Li-Be-F polymetallic metallogeny.The Jiepailing granitoids mainly consist of granitic porphyry and zinnwaldite granite.The two granitoids have an A-type affinity,showing elevated Rb/Sr ratios and significant depletions in Ba,Sr and P.Integrated zircon and monazite U-Pb dating results suggest that granitic porphyry and zinnwaldite granite were emplaced at~89 Ma and~94 Ma,respectively.The low Ce^(4+)/Ce^(3+)ratios of the Jiepailing granitoids,together with significant negative Eu anomalies of the zircons,indicate that their formation occurred under conditions of reduced oxygen fugacity.Through the analysis of zircon Hf-O and whole-rock Nd isotopes,it has been determined that both stages of the Jiepailing granitoids originated in the lower-middle Mesoproterozoic crustal basement[ε_(Nd)(t)=−5.33 to−4.96,t^(C)_(DM)(Nd)=1289-1234 Ma,ε_(Hf)(t)=−4.13 to+2.22,t^(C)_(DM)(Hf)=1418-1015 Ma andδ^(18)O_(Zrc)=6.33‰-7.72‰],with the involvement of mantle-derived materials.Both granitic porphyry and zinnwaldite granite exhibit elevated concentrations of fluorine(F),with the positive correlation between F and Sn emphasizing the crucial role of high F sources in tin mineralization.Drawing upon the study of the Late Cretaceous magma systems in southern Hunan and through comparison with the mineralized granites observed in coastal regions during the Late Cretaceous,a genetic model for the mineralized granites in the Nanling region is developed.When the Paleo-Pacific Plate retreated to the coastal region,the continental crust in southern China underwent extensional thinning and asthenospheric upwelling due to gravitational collapse.Such processes resulted in the partial melting of the middle-lower crustal metamorphic sedimentary basement and the subsequent formation of F-rich granitic magmas,related to tin mineralization.
基金supported financially by the National Natural Science Foundation of China(Grant Nos.41872054 and 41272083)。
文摘The petrogenesis and genetic link to polymetallic mineralization of the granites in the Dayishan complex,southern Hunan province remain debated.Here,we present an integrated study on the petrology,zircon U-Pb ages and whole-rock geochemistry for this complex.Our findings indicate that the southern complex consists of(amphibole-bearing)biotite granites and muscovite granites emplaced at 153-151 Ma,and the central and northern complex consists of two-mica granites and tourmaline-bearing muscovite granites,respectively with the former emplaced at 164 Ma and the latter at 150 Ma.The(amphibole-bearing)biotite granites have SiO_(2) contents of 68.0-73.8 wt% and are enriched in alkalis and rare earth elements and depleted in Sr and Ba.They display Zr+Y+Ce+Nb>350 ppm and 10000×Ga/Al>2.6 along with high zircon saturation temperatures(821-883oC).The two-mica granites and(tourmaline-bearing)muscovite granites have high SiO_(2)(74.4-77.3 wt%)and low Ga/Al,Zr+Nb+Ce+Y,K/Rb,Zr/Hf,and Nb/Ta along with low zircon saturation temperatures(709-817℃).Geochemical characteristics suggest that the(amphibole-bearing)biotite granites are A-type granites generated through shallow dehydration melting of early Paleozoic granitoids,and that the two-mica granites and(tourmaline-bearing)muscovite granites are fractionated A-type granites produced through fractionation crystallization from the(amphibole-bearing)biotite granites accompanied by fluid fractionation.
文摘The relation between conflict and governance has been dominated by type of government rather than by system of government.With increasing conflict in countries with ethnic and religious diversity,the debate has gradually shifted to understand better the link between conflict and system of government.There is a growing evidence that suggests federal system performs better than unitary system in managing diversity and reducing conflict.Decentralization is even seen to be more effective than federal system not only in managing diversity and reducing conflict but also in delivering public goods.This article provides an account of evolution of system of government in South Sudan.It finds a clear association of centralized unitary system with violent conflict and a relative peace during period of decentralized government or federal system.A decentralized federal system may be appropriate for South Sudan in managing diversity and mitigating conflict.Despite the popular demand by their citizens for a federal system to manage diversity and reduce violent conflict,the ruling elites in the post-independent South Sudan adopted instead an autocratic centralized unitary system that contributed among other factors to the persistent violent conflicts,erosion of social cohesion,and rising mistrust between state and citizens and between and among the communities of South Sudan.
文摘There is a growing recognition of the critical role of security governance in advancing democratic transition in the post-conflict environment.Despite such a recognition,the security sector reform concept has overshadowed the importance of the overarching strategic role of security governance in transition to democracy,particularly in Africa.This paper assesses the status and challenges facing security governance and how they thwarted the efforts to furthering the democratic transition in South Sudan.The paper shows a deterioration in security,safety and security governance outcomes since the independence of South Sudan in 2011 with such a trend unlikely to be abated in the near future without strategic interventions.Some of the challenges facing security governance in South Sudan include the legacies of some historical events including the“Big Tent Policy”,absence of strategic leadership,lack of overarching policy framework,impractical and tenuous security arrangements in the 2018 peace agreement,persistent postponement of the first elections,and dysfunctional justice sector.The paper provides some strategic and operational recommendations to improve security governance and advance democratic transition in South Sudan.These recommendations include formulation of an inclusive and people-centered national security policy,rigorous judicial reform,and early political agreement on new political infrastructure if conditions for holding the first national elections are not met in 2026.
基金funded by the National Natural Science Foundation of China(Grant Nos.42072089 and 41530206)。
文摘Both fractional crystallization and fluid-melt-crystal interaction are involved in the formation of highly fractionated granites.This paper assessed those two processes using geochemistry of muscovite and tourmaline and bulkrock chemistry of multi-phase Wangxianling granitoids,South China.Compositional variations suggest the coarse-grained muscovite granite is produced from fractional crystallization of the two-mica granite whereas the fine-grained muscovite granite represents a distinct magma pulse.Progressive fractionation of quartz,feldspar and biotite leads to elevated boron and aluminum content in melt which promoted muscovite and tourmaline to crystallize,which promotes two-mica granite evolving towards tourmaline-bearing muscovite granite.Fluid-melt-crystal interaction occurred at the magmatichydrothermal transitional stage and resulted in the textural and chemical zonings of tourmaline and muscovite in finegrained muscovite granite.The rims of both tourmaline and muscovite are characterized by the enrichment of fluid mobile elements such as Li,Mn,Cs and Zn and heavierδ^(11)B values of the tourmaline rims(-15.0‰to-13.6‰)compared to cores(-15.7‰to-14.3‰).Meanwhile,significant M-type REE tetrad effects(TE_(1,3)=1.07-1.18)and low K/Rb ratios(48-52)also correspond to fluid-melt-crystal interaction.This study shows zoned muscovite and tourmaline can be excellent tracers of fractional crystallization and late-stage fluid-melt-crystal interaction in highly evolved magmatic systems.
基金financially supported by the Basic Foundation of Tianjin University of Commercethe Fund from the Key Laboratory of Continental Dynamics of Ministry of Natural Resources(J2306)。
文摘Deciphering high-pressure granulite-facies metamorphism and anatexis within a collisional orogeny can provide crucial constraints on geodynamic evolution and melt activity during subduction and exhumation.Combining petrographic observations,mineral chemistry,REE in Grt-Cpx thermobarometry,and previous work,at least four stages are suggested for the metamorphic evolution of the mafic granulites in the South Altun,including the protolith stage,the high-pressure granulite-facies stage(909-1037℃and 17.3-30 kbar),medium-pressure granulite-facies overprint(9.1-11.9 kbar and 753-816℃),and subsequent late amphibolite-greenschist-facies metamorphism.Zircon U-Pb dating shows that the mafic granulites underwent high-pressure granulite-facies metamorphism at 497.2±3.7 Ma,while the leucosome formed at 498.2±2.9 Ma.Thus,the leucosomes from the host mafic granulite may have been formed at the high-pressure granulite-facies metamorphic event.The characteristics of zircon morphology,mineral inclusions,low Th/U values,HREE enrichment,and negative Eu anomalies indicate that these zircons from the leucosome were formed from the metamorphic melts.The characteristics of whole-rock major and trace elements as well as Hf isotopic features of zircons between the leucosomes and the host mafic granulite indicate that the melt may have been generated by the partial melting of the host mafic granulite.
基金funded by the South Oil Exploration and Development Company of PetroChina(2021-HNYJ-010).
文摘The Fushan Depression is one of the petroliferous depressions in the Beibuwan Basin,South China Sea.Previous studies have preliminarily explored the origin and source of crude oils in some areas of this depression.Nevertheless,no systematic investigations on the classification and origin of oils and hy-drocarbon migration processes have been made for the entire petroleum system in this depression,which has significantly hindered the hydrocarbon exploration in the region.A total of 32 mudstone and 58 oil samples from the Fushan Depression were analyzed to definite the detailed oil-source correlation within the sequence and sedimentary framework.The organic matter of third member of Paleogene Liushagang Formation(Els(3))source rocks,both deltaic and lacustrine mudstone,are algal-dominated with high abundance of C_(23)tricyclic terpane and C_(30)4-methylsteranes.The deltaic source rocks occur-ring in the first member(Els_(1))and second member(Els_(2))of the Paleogene Liushagang Formation are characterized by high abundance of C_(19+20)tricyclic terpane and oleanane,reflecting a more terrestrial plants contribution.While lacustrine source rocks of Els_(1)and Els_(2)display the reduced input of terrige-nous organic matter with relatively low abundance of C 19+20 tricyclic terpane and oleanane.Three types of oils were identified by their biomarker compositions in this study.Most of the oils discovered in the Huachang and Bailian Els_(1)reservoir belong to group A and were derived from lacustrine source rocks of Els_(1)and Els_(2).Group B oils are found within the Els_(1)and Els_(2)reservoirs,showing a close relation to the deltaic source rocks of Els_(1)and Els_(2),respectively.Group C oils,occurring in the Els3 reservoirs,have a good affinity with the Els3 source rocks.The spatial distribution and accumulation of different groups of oils are mainly controlled by the sedimentary facies and specific structural conditions.The Els_(2)reservoir in the Yong'an area belonging to Group B oil,are adjacent to the source kitchen and could be considered as the favorable exploration area in the future.
