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
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
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
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
Steel catenary riser represents the pioneering riser technology implemented in China’s deep-sea oil and gas opera-tions.Given the complex mechanical conditions of the riser,extensive research has been conducted on it...Steel catenary riser represents the pioneering riser technology implemented in China’s deep-sea oil and gas opera-tions.Given the complex mechanical conditions of the riser,extensive research has been conducted on its dynamic analysis and structural design.This study investigates a deep-sea oil and gas field by developing a coupled model of a semi-submersible platform and steel catenary riser to analyze it mechanical behavior under extreme marine condi-tions.Through multi-objective optimization methodology,the study compares and analyzes suspension point tension and touchdown point stress under various conditions by modifying the suspension position,suspension angle,and catenary length.The optimal configuration parameters were determined:a suspension angle of 12°,suspension position in the southwest direction of the column,and a catenary length of approximately 2000 m.These findings elucidate the impact of configuration parameters on riser dynamic response and establish reasonable parameter layout ranges for adverse sea conditions,offering valuable optimization strategies for steel catenary riser deployment in domestic deep-sea oil and gas fields.展开更多
Granite origin is crucial to understanding the evolution of continental crust,yet many concerns about granite genesis remain yielding ongoing debates.A new integrated study of petrology,geochronology,mineral chemistry...Granite origin is crucial to understanding the evolution of continental crust,yet many concerns about granite genesis remain yielding ongoing debates.A new integrated study of petrology,geochronology,mineral chemistry and whole-rock geochemistry of the Dupangling granitic complex in South China,indicate that the granites in the western complex were emplaced during the Caledonian(418 Ma);they have SiO_(2)contents of 68.1-70.4 wt%,and are calc-alkaline and strongly peraluminous with high maficity[(TFe_(2)O_(3)+MgO)>4.0 wt%]and exhibit^(87)Sr/^(86)Sr(t)of 0.7234-0.7311 andε_(Nd)(t)of-9.0 to-6.7.The granites in the eastern complex,emplaced during the Indosinian(212 Ma),have high SiO_(2)contents(73.3-79.8 wt%)and exhibit affinities with A-type granites,such as enrichment in alkalis and rare earth elements(REEs),and depletion in Sr and Ba along with high TFeO/(TFeO+MgO),Ga/Al and Zr+Y+Ce+Nb;these granites exhibit^(87)Sr/^(86)Sr(t)of 0.7221 andε_(Nd)(t)of-9.2 to-7.5.Geochemical characteristics suggest that the older Caledonian granites were derived through dehydration melting of Paleoproterozoic metasedimentary rocks plus additional(~20%-32%)input from mafic magma,whereas the Indosinian granites were generated through shallow dehydration melting of the Caledonian granitoids.展开更多
Apatite(U-Th)/He and fission track dating and tectono-thermal history modeling were used to reconstruct the Meso-Cenozoic tectonic evolution of the Huangling paleo-uplift in the Middle Yangtze Block,South China.The te...Apatite(U-Th)/He and fission track dating and tectono-thermal history modeling were used to reconstruct the Meso-Cenozoic tectonic evolution of the Huangling paleo-uplift in the Middle Yangtze Block,South China.The tectono-thermal evolution showed different tectonic exhumation/subsidence processes in the tectonic evolution of the foreland basin.The apatite(U-Th)/He ages ranged from 31.3 to 77.8 Ma,recording the thermal events of the Cenozoic Himalayan movement and indicating progressive exhumation extending from the southeast to the northwest.The thermal information of the Mesozoic Yanshan movement period was recorded by the apatite fission track age with a pooled age of 93.8 to 147 Ma.The exhumation of the Huangling paleo-uplift began in the Late Jurassic.The tectono-thermal evolution was characterized by a rapid uplift during 140-115 Ma,subsidence during 115-60 Ma,a rapid uplift during 40-30 Ma,and a slow uplift from 30 Ma to the present.The western Hunan-Hubei Depression was exhumed in the Middle Jurassic,and the tectono-thermal evolution was characterized by a rapid uplift during 160-135 Ma,a slow uplift during 135-50 Ma,a rapid uplift during 50-25 Ma,and a slow uplift from 25 Ma to the present.This Cenozoic exhumation was a response to the far field effect of the eastward growth of the Tibetan Plateau.The Cretaceous basins exposed in the surrounding areas of the Huangling paleo-uplift(Zigui basin,Yichang slope,and Huaguoping synclinorium)are foreland basins formed by the bi-directional compression of the Qinling-Dabie orogenic belt and the Xuefengshan intracontinental deformation system.展开更多
There is significant debate concerning the tectonic characteristics and evolutionary understanding of the South China Block(SCB)during the Early Mesozoic.One of the key points of contention is the tectonic-magmatic ac...There is significant debate concerning the tectonic characteristics and evolutionary understanding of the South China Block(SCB)during the Early Mesozoic.One of the key points of contention is the tectonic-magmatic activity during the Triassic and its dynamic mechanisms.However,research on the detailed chronology and tectonic settings of granite plutons in key regions remains insuffi-cient,limiting the understanding of the tectonic-magmatic dynamic mechanisms in the interior of SCB during the Triassic.In this contribution,we present whole-rock major and trace elemental data,Sr-Nd isotope data,LA-ICP-MS zircon U-Pb age dating,and Lu-Hf isotope data for granites of Dashenshan pluton in the Xiangzhong,northwest part of SCB.The results indicate that the Dashenshan granite has an emplacement age of 208.4-212.5 Ma,characterized by high SiO_(2),Na_(2)O,and K_(2)O contents and low MgO and CaO.The Dashenshan granite is enriched in light rare-earth elements with a significant negative Eu anomaly(averageδEu=0.42).It is also enriched in Rb,K,and Th and shows pronounced depletion in Nb,Ta,and Ti,classifying it as peraluminous calc-alkaline granite,specifically of the I-type.The zircon ε_(Hf(t)) values range from−8.39 to−4.4,with an average of−5.82,and the Sr-Nd isotopes are relatively enriched[ε_(Nd)(t)=−9.31 to−6.8].Combining these geochemical characteristics,it is revealed that the Dashenshan granite was derived from the partial melting of middle to upper crustal metamorphic basement materials under medium-to low-temperature conditions,with possible minor contributions from mantle-derived materials.Furthermore,it underwent fractional crystallization,including plagioclase differentiation.By integrating the geochemical features and spatial distribution of Triassic granites in SCB,this study suggests that the regional tectonic evolution of SCB during the Triassic was primarily controlled by the collision of the SCB with the Indochina Block and the North China Block.In Xiangzhong,the tectonic setting transitioned from syn-collisional compression to post-collisional extension during the Late Triassic.The Dashenshan pluton formed in a post-collisional extensional setting,resulting from the decompression melting of middle-to-upper crustal rocks.The upwelling of the asthenosphere and upward heat transfer likely played a significant role in the formation of the Dashenshan granitic magma.展开更多
This study aims to determine the variation and controlling factors of shale gas adsorption capacity in reservoirs in the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation(also referred to as ...This study aims to determine the variation and controlling factors of shale gas adsorption capacity in reservoirs in the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation(also referred to as the WF-LMX formations),South China.Based on data obtained using scanning helium ion microscopy(HIM)and nitrogen(N_(2))and methane(CH_(4))adsorption experiments,this study analyzed the organic pore heterogeneity of shales in the WF-LMX formations in well A and its effect on shale gas adsorption.Using the Frenkel-Halsey-Hill(FHH)model,data from N_(2) adsorption experiments were converted into fractal dimensions,which can reflect the complexity and heterogeneity of organic pores while also serving as a novel indicator for quantitatively assessing the pore structure complexity.The results indicate that shales in the WF-LMX formations in well A can be divided into two sections:(Ⅰ)the Wufeng Formation and the lower Longmaxi Formation(depths:ca.2871.0-2898.6 m),and(Ⅱ)the upper Longmaxi Formation(depths:<2871.0 m).Organic pores in Section Ⅰ typically exhibit complex internal structures,coarse surfaces,and interconnectivity,whereas those in Section Ⅱ are simple,smooth,and isolated.Moreover,the former possesses larger specific surface areas(SSAs)than the latter.A fractal analysis reveals that organic pores in the shale sequence can be classified into micropores(<2 nm),mesopores(2-10 nm),and macropores(>10 nm).The calculated fractal dimensions show greater heterogeneity of organic pores,especially macropores,in Section Ⅰ compared to Section Ⅱ.The results also reveal that organic macropores are the primary pores controlling the SSAs of organic pores in shale reservoirs in the WF-LMX formations.Organic pores in Section Ⅰ manifest a superior shale gas adsorption capacity compared to Section Ⅱ.The heterogeneity of organic pores might affect the adsorption capacity of shales in the formations.Generally,organic macropores in Section Ⅰ of the shale sequence exhibit more complex structures and larger SSAs,leading to a stronger absorption capacity of shale reservoirs in Section Ⅰ compared to Section Ⅱ.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
Composite granitic pluton with distinct units is a potential target for identifying its detailed magma evolution.Here,we present zircon U-Pb ages and Hf isotope,whole-rock major and trace element compositions and Nd-P...Composite granitic pluton with distinct units is a potential target for identifying its detailed magma evolution.Here,we present zircon U-Pb ages and Hf isotope,whole-rock major and trace element compositions and Nd-Pb isotopes of the Wangxiang composite pluton,South China.New ages obtained show that these rocks were generated in Late Jurassic(ca.156–158 Ma).The rocks are divided into low silica(SiO_(2)<67 wt.%,biotite granodiorites and their dioritic enclaves)and high silica ones(SiO_(2)>71 wt.%,two-mica granites,garnet-bearing muscovite granites and muscovite granites).The high silica rocks are enriched in light rare earth elements(LREEs)relative to heavy REEs(HREEs)((La/Yb)_(N)=15.6–41.9,while the low silica rocks are not(0.7–76.6).All rocks show various negative Ti,Sr,Eu and strong positive Pb anomalies.The low silica rocks have less negative values ofε_(Nd)(t)(-8.79 to-6.99),similar values of~((206)Pb/^(204)Pb)_(i)(18.155–18.346)andε_(Hf)(t)(-9.51 to-3.47,except one-12.84),compared to the high silica rocks(ε_(Nd)(t)=-11.14 to-10.26;^((206)Pb/^(204)Pb)_(i)=17.935–19.093;ε_(Hf)(t)=-12.03 to-7.15,except one-2.41).Data suggest that the parental magma of the studied rocks(represented by enclaves)was produced by partial melting of a garnet-free crustal source.Subsequently those crustal magmas formed the more evolved units through assimilation and fractional crystallization processes,and fluid enrichment during the final magmatic activity.Combining our results with previous multidisciplinary studies,we propose that the key factor to control the evolution of Wangxiang composite pluton is discrete emplacement of crustal magmas by dyking.展开更多
Using literature published from 2010 onwards, this study investigates the ~3 500 km extension of the shallow shelf current in the South China Sea(SCS) during the winter and summer monsoons. This current is later ackno...Using literature published from 2010 onwards, this study investigates the ~3 500 km extension of the shallow shelf current in the South China Sea(SCS) during the winter and summer monsoons. This current is later acknowledged as the South China Sea shallow shelf Current(SCSSC). This current is primarily driven by monsoonal winds, and influenced by regional river plumes [Zhujiang(Pearl) River, Hong River, Mekong River] and the prominent South China Sea Warm Current(SCSWC) and South China Sea Western Boundary Current(SCSWBC). The current exhibits significant seasonal variations in both direction and pattern. During winter, it flows along the northern South China Sea's(NSCS) shelf and splits into two branches at the east of Hainan Island. One branch enters the Beibu Gulf through the Qiongzhou Strait and forms a major cyclonic circulation within the gulf, while the other branch flows southwestward along the southern coast of Hainan Island. These branches converge around 16°N latitude at the east of the Vietnamese shelf, then flow southward along the Sunda Shelf, where they deflect southwestward in “broadband”forms before curving southeastward along the east coast of Peninsular Malaysia(ECPM) and exiting via the Karimata Strait. In summer, the current exhibits a complex pattern. At the Sunda Shelf, it flows northwestward along the ECPM,then deflects northeastward around 6°N latitude, forming the Sunda Shelf's anti-cyclonic eddy(SSE) and causing upwelling on the east coast of Peninsular Malaysia(ECPMU). Near the eastern Vietnamese shelf, the current splits around 11°-12°N latitude into three distinct currents: the southward-flowing Vietnam Current, the northward-flowing Vietnam Meandering Current(VMC), and the southward-flowing SCSWBC. The VMC flows northward and then deflects northeastward south of Hainan Island, continuing northeastward along the NSCS's shelf and exiting through the Taiwan Strait.展开更多
This study conducts a comparative investigation between short-lived(3-8 days)and long-lived(9-24 days)break events of the South China Sea summer monsoon during 1979-2020,focusing on their statistical characteristics a...This study conducts a comparative investigation between short-lived(3-8 days)and long-lived(9-24 days)break events of the South China Sea summer monsoon during 1979-2020,focusing on their statistical characteristics and potential mechanisms for their different persistence.Results suggest that both types of events are characterized by anomalously suppressed convection accompanied by an anomalous anticyclone during the break period.However,these convection and circulation anomalies exhibit more localized patterns for short-lived events,but possess larger spatial scales and stronger intensities for long-lived events.The influence of tropical intraseasonal oscillations(ISOs)on short-and long-lived events is explored to interpret their different durations.It is found that for short-lived events,the 10-25-day oscillation is dominant in initiating and terminating the break,while the impact of the 30-60-day oscillation is secondary,thus resulting in a brief break period.In contrast,for long-lived events,the 10-25-day oscillation contributes to break development rather than its initiation,and concurrently,the 30-60-day oscillation shows a remarkable enhancement and plays a decisive role in prolonging the break duration.Furthermore,we find that long-lived events are preceded by significant ISO activities approximately two weeks before their occurrence,which can be regarded as efficient predictors.Associated with these precursory ISOs,the occurrence probability of break days for long-lived events can rise up to triple their original probability(35.43%vs.11.21%).展开更多
Studying the characteristics and mechanisms of convective and non-convective cirrus clouds over the South China Sea is vital for their impact on regional climate dynamics,and enhancing predictive models for weather an...Studying the characteristics and mechanisms of convective and non-convective cirrus clouds over the South China Sea is vital for their impact on regional climate dynamics,and enhancing predictive models for weather and climate forecasts.This study utilizes eight years of CALIPSO data(from March 2007 to February 2015)to investigate convective and non-convective cirrus clouds.Explicit new insights include the observation that convective cirrus cloud samples are three times more numerous than non-convective cirrus clouds.Convective cirrus clouds are associated with humid conditions and demonstrate higher ice water content(IWC)values ranging from 10^(−3)to 10^(−1)g m^(−3),whereas non-convective cirrus clouds tend to be drier,exhibiting IWC values ranging from 10^(−4)to 10^(−3)g m^(−3).Both cirrus cloud types exhibit a maximum cloud fraction at 10°N.Convective cirrus reach their peak cloud fraction at an altitude of 14 km,while non-convective cirrus typically occur at altitudes between 15 and 16 km.The seasonal variability of the convective cirrus cloud fraction primarily reflects bottom-up positive specific humidity anomalies originating from convective activity,whereas the non-convective cirrus cloud fraction is influenced by top-down negative temperature anomalies.展开更多
Revealing regional climate changes is vital for policymaking activities related to climate change adaptation and mitigation.South China is a well-developed region with a dense population,but the level of uncertainty i...Revealing regional climate changes is vital for policymaking activities related to climate change adaptation and mitigation.South China is a well-developed region with a dense population,but the level of uncertainty in climate projections remains to be evaluated in detail.In this study,we comprehensively assessed the historical simulations and future projections of climate change in South China based on CMIP5/CMIP6 models.We show evidence that CMIP5/CMIP6 models can skillfully reproduce the observed distributions of annual/seasonal mean temperature but show much lower skill for precipitation.CMIP6 outperforms CMIP5 in the historical simulations,as evidenced by more models with lower bias magnitude and higher skill scores.During 2021–2100,the annual mean temperature over South China is projected to increase significantly at a rate of 0.53(0.42–0.63)and 0.59(0.52–0.66)℃(10 yr)^(-1),while precipitation is projected to increase slightly at a rate of 0.78(0.15–1.56)and 1.52(0.91–2.30)%(10 yr)^(-1),under the RCP8.5 and SSP5-8.5 scenarios,respectively.CMIP6 models project larger annual/seasonal mean temperature and precipitation trends than CMIP5 models under equivalent scenarios.The temperature in South China is projected to increase robustly by more than1.5℃during 2041–2060 under RCP4.5 and SSP2-4.5,but by 4.5℃during 2081–2100,under RCP8.5 and SSP5-8.5 with respect to 1850–1900.The uncertainty in temperature projections is mainly dominated by model uncertainty and scenario uncertainty,while internal uncertainty contributes some of the uncertainty during the near-term.The uncertainty in precipitation projection stems mainly from internal uncertainty and model uncertainty.For both the temperature and precipitation projection uncertainty,the relative sizes of contributions from the main contributors vary with time and show obvious seasonal differences.展开更多
Exposure to green-blue spaces(GBS)affects the mental well-being of visitors,which should be an area-dependent effect with a critical range for perceiving emotions.This interacts with the road network(RN)to access GBS ...Exposure to green-blue spaces(GBS)affects the mental well-being of visitors,which should be an area-dependent effect with a critical range for perceiving emotions.This interacts with the road network(RN)to access GBS over a range,but the relevant evidence is unclear according to any case-specific demonstration.In this study,we selected 23 urban parks with varied populations from 19 cities in South China to identify the combined effects of landscape features and overlapped RN in different buffer zones on visitors’emotional perceptions.Sentiments were analyzed by rating facial expressions to happy,sad,and neutral scores from 2385 visitors’photos from a social network in 2020.Landscape metrics and RN were assessed remotely in buffer areas with radii of 1,3,5,and 10 km.The results showed that positive emotions were low in close areas(<3 km radius)with large blue spaces and dense national roads.In 10 km radius areas,dense roads at town-city levels were perceived to reduce positive emotions.Dense high-rank roads should be avoided around parks in areas with radii≤10 km if visitors perceive more positive sentiments.This is because the dense RN could diminish visitors’ability to perceive positive emotions in GBS when close to the park.The results of this study could help improve planning schemes with more opportunities to offer mental well-being in GBS-RN landscapes.展开更多
Based on petroleum exploration and new progress of oil and gas geology study in the Qiongdongnan Basin,combined with seismic,logging,drilling,core,sidewall coring,geochemistry data,a systematic study is conducted on t...Based on petroleum exploration and new progress of oil and gas geology study in the Qiongdongnan Basin,combined with seismic,logging,drilling,core,sidewall coring,geochemistry data,a systematic study is conducted on the source,reservoir-cap conditions,trap types,migration and accumulation characteristics,enrichment mechanisms,and reservoir formation models of ultra-deep water and ultra-shallow natural gas,taking the Lingshui 36-1 gas field as an example.(1)The genetic types of the ultra-deep water and ultra-shallow natural gas in the Qiongdongnan Basin include thermogenic gas and biogenic gas,and dominated by thermogenic gas.(2)The reservoirs are mainly composed of the Quaternary deep-water submarine fan sandstone.(3)The types of cap rocks include deep-sea mudstone,mass transport deposits mudstone,and hydrate-bearing formations.(4)The types of traps are mainly lithological,and also include structural-lithological traps.(5)The migration channels include vertical transport channels such as faults,gas chimneys,fracture zones,and lateral transport layers such as large sand bodies and unconformity surfaces,forming a single or composite transport framework.A new natural gas accumulation model is proposed for ultra-deep water and ultra-shallow layers,that is,dual source hydrocarbon supply,gas chimney and submarine fan composite migration,deep-sea mudstone-mass transport deposits mudstone-hydrate-bearing strata ternary sealing,late dynamic accumulation,and large-scale enrichment at ridges.The new understanding obtained from the research has reference and enlightening significance for the next step of deepwater and ultra-shallow layers,as well as oil and gas exploration in related fields or regions.展开更多
The Dabaoshan porphyry Cu deposit(420 kilotons(kt)of Cu@0.36%)is located in South China.The newly discovered Cu orebodies are hosted in the dacite porphyry adjacent to a granodiorite porphyry.The alteration and minera...The Dabaoshan porphyry Cu deposit(420 kilotons(kt)of Cu@0.36%)is located in South China.The newly discovered Cu orebodies are hosted in the dacite porphyry adjacent to a granodiorite porphyry.The alteration and mineralization timing and stages of the porphyry Cu deposit were not well-constrained.In this study,we combine field mapping,petrography,whole-rock geochemistry,hydrothermal rutile U-Pb dating and Cu isotopes to synthesize an ore model at Dabaoshan.In situ hydrothermal rutile U-Pb dating yields an age of 159±13 Ma,which brackets the timing of porphyry Cu mineralization.From top to bottom,the alteration zones in Dabaoshan are divided into quartz-sericite,biotite,chlorite-epidote,and chlorite-sericite subzones.Veins are classified into four stages(Stage 1 to 4)with Stage 4 quartz-sericite-chalcopyrite veins being the main Cu ore-bearing veins.The mineralized dacite porphyry has high SiO_(2),but low MgO,CaO,and Na_(2)O contents.The chalcopyrite hosted in veins exhibitsδ^(65)Cu=values ranging from−1.29‰to 0.51‰.Such copper isotope fractionation is attributed to vapor-brine phase separation,and mixing of fluids from different geochemical reservoirs.The timing of Cu mineralization and hydrothermal alteration support that the Jurassic granodiorite porphyry is an ore-forming intrusion at Dabaoshan.展开更多
As one of the micro-blocks dispersed in the South China Sea(SCS),the Xisha Islands are covered by thick Cenozoic sedimentary layers,making it challenging to obtain magmatic rocks.Well CK-2 is a kilometer-scale scienti...As one of the micro-blocks dispersed in the South China Sea(SCS),the Xisha Islands are covered by thick Cenozoic sedimentary layers,making it challenging to obtain magmatic rocks.Well CK-2 is a kilometer-scale scientific drilling project on the Xisha Islands in the northwestern SCS.It penetrates the thick reef limestone and reaches basaltic pyroclastic rocks.This study presents the whole-rock and olivine compositions of the basaltic volcaniclastic rocks from Well CK-2.These rocks exhibited ocean island basalt signatures characterized by the enrichment of light rare earth elements and high-field-strength elements.Compared with partial melting products derived from mantle peridotite,whole-rock compositions showed elevated Fe/Mn and Zn/Fe mass ratios.Additionally,olivines were characterized by a lower Ca content,higher Ni content,elevated Fe/Mn mass ratios,and moderate Mn/Zn mass ratios compared to those crystallized from peridotitic melts.The compositions of both the whole-rock and olivine phenocrysts indicate the presence of pyroxenite in the mantle source,which likely formed through the reaction of recycled oceanic crust with the surrounding mantle peridotite.Using the olivine-liquid Mg-Fe exchange thermometer,this study derived mantle potential temperatures(T_(p))ranging from 1502℃to 1756℃,which is consistent with those of plume-related ocean island basalts.Furthermore,the basaltic volcaniclastic rocks exhibit low H_(2)O contents(0.01%–1.47%),which were significantly lower than those found in the primary magmas of Large Igneous Provinces.These results suggest that the basaltic volcaniclastic rocks on the Xisha Islands originated from a volatile-poor mantle plume source.展开更多
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.
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.
基金financially supported by the National Key Research and Development Program of China(Grant No.2022YFC2806100)the National Natural Science Foundation of China(Grant Nos.U22B20126 and 52374020)+1 种基金Science Foundation of China University of Petroleum,Beijing(Grant No.2462025QNXZ009)Beijing Nova Program(Grant No.20250484913).
文摘Steel catenary riser represents the pioneering riser technology implemented in China’s deep-sea oil and gas opera-tions.Given the complex mechanical conditions of the riser,extensive research has been conducted on its dynamic analysis and structural design.This study investigates a deep-sea oil and gas field by developing a coupled model of a semi-submersible platform and steel catenary riser to analyze it mechanical behavior under extreme marine condi-tions.Through multi-objective optimization methodology,the study compares and analyzes suspension point tension and touchdown point stress under various conditions by modifying the suspension position,suspension angle,and catenary length.The optimal configuration parameters were determined:a suspension angle of 12°,suspension position in the southwest direction of the column,and a catenary length of approximately 2000 m.These findings elucidate the impact of configuration parameters on riser dynamic response and establish reasonable parameter layout ranges for adverse sea conditions,offering valuable optimization strategies for steel catenary riser deployment in domestic deep-sea oil and gas fields.
基金supported financially by the National Natural Science Foundation of China(Grant Nos.41872054 and 41272083)。
文摘Granite origin is crucial to understanding the evolution of continental crust,yet many concerns about granite genesis remain yielding ongoing debates.A new integrated study of petrology,geochronology,mineral chemistry and whole-rock geochemistry of the Dupangling granitic complex in South China,indicate that the granites in the western complex were emplaced during the Caledonian(418 Ma);they have SiO_(2)contents of 68.1-70.4 wt%,and are calc-alkaline and strongly peraluminous with high maficity[(TFe_(2)O_(3)+MgO)>4.0 wt%]and exhibit^(87)Sr/^(86)Sr(t)of 0.7234-0.7311 andε_(Nd)(t)of-9.0 to-6.7.The granites in the eastern complex,emplaced during the Indosinian(212 Ma),have high SiO_(2)contents(73.3-79.8 wt%)and exhibit affinities with A-type granites,such as enrichment in alkalis and rare earth elements(REEs),and depletion in Sr and Ba along with high TFeO/(TFeO+MgO),Ga/Al and Zr+Y+Ce+Nb;these granites exhibit^(87)Sr/^(86)Sr(t)of 0.7221 andε_(Nd)(t)of-9.2 to-7.5.Geochemical characteristics suggest that the older Caledonian granites were derived through dehydration melting of Paleoproterozoic metasedimentary rocks plus additional(~20%-32%)input from mafic magma,whereas the Indosinian granites were generated through shallow dehydration melting of the Caledonian granitoids.
基金funded by the National Natural Science Foundation of China(U2244208,42302138)China Postdoctoral Science Foundation(No.2020M733869)Science Foundation of China University of Petroleum,Beijing(No.2462023XKBH003).
文摘Apatite(U-Th)/He and fission track dating and tectono-thermal history modeling were used to reconstruct the Meso-Cenozoic tectonic evolution of the Huangling paleo-uplift in the Middle Yangtze Block,South China.The tectono-thermal evolution showed different tectonic exhumation/subsidence processes in the tectonic evolution of the foreland basin.The apatite(U-Th)/He ages ranged from 31.3 to 77.8 Ma,recording the thermal events of the Cenozoic Himalayan movement and indicating progressive exhumation extending from the southeast to the northwest.The thermal information of the Mesozoic Yanshan movement period was recorded by the apatite fission track age with a pooled age of 93.8 to 147 Ma.The exhumation of the Huangling paleo-uplift began in the Late Jurassic.The tectono-thermal evolution was characterized by a rapid uplift during 140-115 Ma,subsidence during 115-60 Ma,a rapid uplift during 40-30 Ma,and a slow uplift from 30 Ma to the present.The western Hunan-Hubei Depression was exhumed in the Middle Jurassic,and the tectono-thermal evolution was characterized by a rapid uplift during 160-135 Ma,a slow uplift during 135-50 Ma,a rapid uplift during 50-25 Ma,and a slow uplift from 25 Ma to the present.This Cenozoic exhumation was a response to the far field effect of the eastward growth of the Tibetan Plateau.The Cretaceous basins exposed in the surrounding areas of the Huangling paleo-uplift(Zigui basin,Yichang slope,and Huaguoping synclinorium)are foreland basins formed by the bi-directional compression of the Qinling-Dabie orogenic belt and the Xuefengshan intracontinental deformation system.
基金supported financially by the Research Foundation of the Department of Natural Resources of Hunan Province(20230135DZ)the Provincial Natural Science Foundation of Hunan(2024JJ7080)+1 种基金the Scientific Research Fund of Hunan Provincial Education Department(23C0320)Hunan Provincial College Student Innovation and Entrepreneurship Training Project(S202311527014).
文摘There is significant debate concerning the tectonic characteristics and evolutionary understanding of the South China Block(SCB)during the Early Mesozoic.One of the key points of contention is the tectonic-magmatic activity during the Triassic and its dynamic mechanisms.However,research on the detailed chronology and tectonic settings of granite plutons in key regions remains insuffi-cient,limiting the understanding of the tectonic-magmatic dynamic mechanisms in the interior of SCB during the Triassic.In this contribution,we present whole-rock major and trace elemental data,Sr-Nd isotope data,LA-ICP-MS zircon U-Pb age dating,and Lu-Hf isotope data for granites of Dashenshan pluton in the Xiangzhong,northwest part of SCB.The results indicate that the Dashenshan granite has an emplacement age of 208.4-212.5 Ma,characterized by high SiO_(2),Na_(2)O,and K_(2)O contents and low MgO and CaO.The Dashenshan granite is enriched in light rare-earth elements with a significant negative Eu anomaly(averageδEu=0.42).It is also enriched in Rb,K,and Th and shows pronounced depletion in Nb,Ta,and Ti,classifying it as peraluminous calc-alkaline granite,specifically of the I-type.The zircon ε_(Hf(t)) values range from−8.39 to−4.4,with an average of−5.82,and the Sr-Nd isotopes are relatively enriched[ε_(Nd)(t)=−9.31 to−6.8].Combining these geochemical characteristics,it is revealed that the Dashenshan granite was derived from the partial melting of middle to upper crustal metamorphic basement materials under medium-to low-temperature conditions,with possible minor contributions from mantle-derived materials.Furthermore,it underwent fractional crystallization,including plagioclase differentiation.By integrating the geochemical features and spatial distribution of Triassic granites in SCB,this study suggests that the regional tectonic evolution of SCB during the Triassic was primarily controlled by the collision of the SCB with the Indochina Block and the North China Block.In Xiangzhong,the tectonic setting transitioned from syn-collisional compression to post-collisional extension during the Late Triassic.The Dashenshan pluton formed in a post-collisional extensional setting,resulting from the decompression melting of middle-to-upper crustal rocks.The upwelling of the asthenosphere and upward heat transfer likely played a significant role in the formation of the Dashenshan granitic magma.
基金funded by the National Natural Science Foundation Research of China(No.41902127,41802157)the Shandong Provincial Natural Science Foundation,China(No.ZR2018BD015).
文摘This study aims to determine the variation and controlling factors of shale gas adsorption capacity in reservoirs in the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation(also referred to as the WF-LMX formations),South China.Based on data obtained using scanning helium ion microscopy(HIM)and nitrogen(N_(2))and methane(CH_(4))adsorption experiments,this study analyzed the organic pore heterogeneity of shales in the WF-LMX formations in well A and its effect on shale gas adsorption.Using the Frenkel-Halsey-Hill(FHH)model,data from N_(2) adsorption experiments were converted into fractal dimensions,which can reflect the complexity and heterogeneity of organic pores while also serving as a novel indicator for quantitatively assessing the pore structure complexity.The results indicate that shales in the WF-LMX formations in well A can be divided into two sections:(Ⅰ)the Wufeng Formation and the lower Longmaxi Formation(depths:ca.2871.0-2898.6 m),and(Ⅱ)the upper Longmaxi Formation(depths:<2871.0 m).Organic pores in Section Ⅰ typically exhibit complex internal structures,coarse surfaces,and interconnectivity,whereas those in Section Ⅱ are simple,smooth,and isolated.Moreover,the former possesses larger specific surface areas(SSAs)than the latter.A fractal analysis reveals that organic pores in the shale sequence can be classified into micropores(<2 nm),mesopores(2-10 nm),and macropores(>10 nm).The calculated fractal dimensions show greater heterogeneity of organic pores,especially macropores,in Section Ⅰ compared to Section Ⅱ.The results also reveal that organic macropores are the primary pores controlling the SSAs of organic pores in shale reservoirs in the WF-LMX formations.Organic pores in Section Ⅰ manifest a superior shale gas adsorption capacity compared to Section Ⅱ.The heterogeneity of organic pores might affect the adsorption capacity of shales in the formations.Generally,organic macropores in Section Ⅰ of the shale sequence exhibit more complex structures and larger SSAs,leading to a stronger absorption capacity of shale reservoirs in Section Ⅰ compared to Section Ⅱ.
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.
基金provided by the National Natural Science Foundation of China(No.41002022)the National Key R&D Program of China(No.2017YFC0602402)+3 种基金the Provincial Natural Science Foundation of Hunan(No.2019JJ50831)the Opening Foundation of State Key Laboratory of Continental Dynamics,Northwest University(No.20LCD08)the Funded by Open Research Fund Programme of the Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education(No.2018YSJS07)Bruna B.Carvalho is thankful to MIUR(Ministero dell’Istruzione,dell’Universitàe della Ricerca)for the award of a grant(No.PNRA18_00103)。
文摘Composite granitic pluton with distinct units is a potential target for identifying its detailed magma evolution.Here,we present zircon U-Pb ages and Hf isotope,whole-rock major and trace element compositions and Nd-Pb isotopes of the Wangxiang composite pluton,South China.New ages obtained show that these rocks were generated in Late Jurassic(ca.156–158 Ma).The rocks are divided into low silica(SiO_(2)<67 wt.%,biotite granodiorites and their dioritic enclaves)and high silica ones(SiO_(2)>71 wt.%,two-mica granites,garnet-bearing muscovite granites and muscovite granites).The high silica rocks are enriched in light rare earth elements(LREEs)relative to heavy REEs(HREEs)((La/Yb)_(N)=15.6–41.9,while the low silica rocks are not(0.7–76.6).All rocks show various negative Ti,Sr,Eu and strong positive Pb anomalies.The low silica rocks have less negative values ofε_(Nd)(t)(-8.79 to-6.99),similar values of~((206)Pb/^(204)Pb)_(i)(18.155–18.346)andε_(Hf)(t)(-9.51 to-3.47,except one-12.84),compared to the high silica rocks(ε_(Nd)(t)=-11.14 to-10.26;^((206)Pb/^(204)Pb)_(i)=17.935–19.093;ε_(Hf)(t)=-12.03 to-7.15,except one-2.41).Data suggest that the parental magma of the studied rocks(represented by enclaves)was produced by partial melting of a garnet-free crustal source.Subsequently those crustal magmas formed the more evolved units through assimilation and fractional crystallization processes,and fluid enrichment during the final magmatic activity.Combining our results with previous multidisciplinary studies,we propose that the key factor to control the evolution of Wangxiang composite pluton is discrete emplacement of crustal magmas by dyking.
基金Long-Term Research Grant Scheme (LRGS:56041)Interaction of Ocean Dynamics With The Climate System of Past,Present,and Future Using Ocean Observation Integrated Data and Numerical Modeling。
文摘Using literature published from 2010 onwards, this study investigates the ~3 500 km extension of the shallow shelf current in the South China Sea(SCS) during the winter and summer monsoons. This current is later acknowledged as the South China Sea shallow shelf Current(SCSSC). This current is primarily driven by monsoonal winds, and influenced by regional river plumes [Zhujiang(Pearl) River, Hong River, Mekong River] and the prominent South China Sea Warm Current(SCSWC) and South China Sea Western Boundary Current(SCSWBC). The current exhibits significant seasonal variations in both direction and pattern. During winter, it flows along the northern South China Sea's(NSCS) shelf and splits into two branches at the east of Hainan Island. One branch enters the Beibu Gulf through the Qiongzhou Strait and forms a major cyclonic circulation within the gulf, while the other branch flows southwestward along the southern coast of Hainan Island. These branches converge around 16°N latitude at the east of the Vietnamese shelf, then flow southward along the Sunda Shelf, where they deflect southwestward in “broadband”forms before curving southeastward along the east coast of Peninsular Malaysia(ECPM) and exiting via the Karimata Strait. In summer, the current exhibits a complex pattern. At the Sunda Shelf, it flows northwestward along the ECPM,then deflects northeastward around 6°N latitude, forming the Sunda Shelf's anti-cyclonic eddy(SSE) and causing upwelling on the east coast of Peninsular Malaysia(ECPMU). Near the eastern Vietnamese shelf, the current splits around 11°-12°N latitude into three distinct currents: the southward-flowing Vietnam Current, the northward-flowing Vietnam Meandering Current(VMC), and the southward-flowing SCSWBC. The VMC flows northward and then deflects northeastward south of Hainan Island, continuing northeastward along the NSCS's shelf and exiting through the Taiwan Strait.
基金supported by the National Natural Science Foundation of China(Grant No.42275025)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2023084).
文摘This study conducts a comparative investigation between short-lived(3-8 days)and long-lived(9-24 days)break events of the South China Sea summer monsoon during 1979-2020,focusing on their statistical characteristics and potential mechanisms for their different persistence.Results suggest that both types of events are characterized by anomalously suppressed convection accompanied by an anomalous anticyclone during the break period.However,these convection and circulation anomalies exhibit more localized patterns for short-lived events,but possess larger spatial scales and stronger intensities for long-lived events.The influence of tropical intraseasonal oscillations(ISOs)on short-and long-lived events is explored to interpret their different durations.It is found that for short-lived events,the 10-25-day oscillation is dominant in initiating and terminating the break,while the impact of the 30-60-day oscillation is secondary,thus resulting in a brief break period.In contrast,for long-lived events,the 10-25-day oscillation contributes to break development rather than its initiation,and concurrently,the 30-60-day oscillation shows a remarkable enhancement and plays a decisive role in prolonging the break duration.Furthermore,we find that long-lived events are preceded by significant ISO activities approximately two weeks before their occurrence,which can be regarded as efficient predictors.Associated with these precursory ISOs,the occurrence probability of break days for long-lived events can rise up to triple their original probability(35.43%vs.11.21%).
基金supported financially by the National Natural Science Foundation of China[grant numbers 42027804,41775026,and 41075012]。
文摘Studying the characteristics and mechanisms of convective and non-convective cirrus clouds over the South China Sea is vital for their impact on regional climate dynamics,and enhancing predictive models for weather and climate forecasts.This study utilizes eight years of CALIPSO data(from March 2007 to February 2015)to investigate convective and non-convective cirrus clouds.Explicit new insights include the observation that convective cirrus cloud samples are three times more numerous than non-convective cirrus clouds.Convective cirrus clouds are associated with humid conditions and demonstrate higher ice water content(IWC)values ranging from 10^(−3)to 10^(−1)g m^(−3),whereas non-convective cirrus clouds tend to be drier,exhibiting IWC values ranging from 10^(−4)to 10^(−3)g m^(−3).Both cirrus cloud types exhibit a maximum cloud fraction at 10°N.Convective cirrus reach their peak cloud fraction at an altitude of 14 km,while non-convective cirrus typically occur at altitudes between 15 and 16 km.The seasonal variability of the convective cirrus cloud fraction primarily reflects bottom-up positive specific humidity anomalies originating from convective activity,whereas the non-convective cirrus cloud fraction is influenced by top-down negative temperature anomalies.
基金jointly supported by the Joint Funds of the National Natural Science Foundation of China(Grant No.U2242203)the National Natural Science Foundation of China(Grant No.41905070)+4 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2021A1515011421,2023A1515240067,2023B1515020009)the National Key R&D Program of China(Grant No.2018YFC1505801)supported by the Guangdong Provincial Marine Meteorology Science Data Center(2024B1212070014)the China Meteorology Administration Key Innovation Team of Tropical Meteorology(Grant No.CMA2023ZD08)State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences(Project No.LTO2311)。
文摘Revealing regional climate changes is vital for policymaking activities related to climate change adaptation and mitigation.South China is a well-developed region with a dense population,but the level of uncertainty in climate projections remains to be evaluated in detail.In this study,we comprehensively assessed the historical simulations and future projections of climate change in South China based on CMIP5/CMIP6 models.We show evidence that CMIP5/CMIP6 models can skillfully reproduce the observed distributions of annual/seasonal mean temperature but show much lower skill for precipitation.CMIP6 outperforms CMIP5 in the historical simulations,as evidenced by more models with lower bias magnitude and higher skill scores.During 2021–2100,the annual mean temperature over South China is projected to increase significantly at a rate of 0.53(0.42–0.63)and 0.59(0.52–0.66)℃(10 yr)^(-1),while precipitation is projected to increase slightly at a rate of 0.78(0.15–1.56)and 1.52(0.91–2.30)%(10 yr)^(-1),under the RCP8.5 and SSP5-8.5 scenarios,respectively.CMIP6 models project larger annual/seasonal mean temperature and precipitation trends than CMIP5 models under equivalent scenarios.The temperature in South China is projected to increase robustly by more than1.5℃during 2041–2060 under RCP4.5 and SSP2-4.5,but by 4.5℃during 2081–2100,under RCP8.5 and SSP5-8.5 with respect to 1850–1900.The uncertainty in temperature projections is mainly dominated by model uncertainty and scenario uncertainty,while internal uncertainty contributes some of the uncertainty during the near-term.The uncertainty in precipitation projection stems mainly from internal uncertainty and model uncertainty.For both the temperature and precipitation projection uncertainty,the relative sizes of contributions from the main contributors vary with time and show obvious seasonal differences.
基金Under the auspices of the National Natural Science Foundation of China(No.41971122,41861017,31600496)the Fundamental Research Funds for the Central Universities(No.0919/140193)。
文摘Exposure to green-blue spaces(GBS)affects the mental well-being of visitors,which should be an area-dependent effect with a critical range for perceiving emotions.This interacts with the road network(RN)to access GBS over a range,but the relevant evidence is unclear according to any case-specific demonstration.In this study,we selected 23 urban parks with varied populations from 19 cities in South China to identify the combined effects of landscape features and overlapped RN in different buffer zones on visitors’emotional perceptions.Sentiments were analyzed by rating facial expressions to happy,sad,and neutral scores from 2385 visitors’photos from a social network in 2020.Landscape metrics and RN were assessed remotely in buffer areas with radii of 1,3,5,and 10 km.The results showed that positive emotions were low in close areas(<3 km radius)with large blue spaces and dense national roads.In 10 km radius areas,dense roads at town-city levels were perceived to reduce positive emotions.Dense high-rank roads should be avoided around parks in areas with radii≤10 km if visitors perceive more positive sentiments.This is because the dense RN could diminish visitors’ability to perceive positive emotions in GBS when close to the park.The results of this study could help improve planning schemes with more opportunities to offer mental well-being in GBS-RN landscapes.
基金Supported by the Research Project of CNOOC(KJZH-2021-0003-00).
文摘Based on petroleum exploration and new progress of oil and gas geology study in the Qiongdongnan Basin,combined with seismic,logging,drilling,core,sidewall coring,geochemistry data,a systematic study is conducted on the source,reservoir-cap conditions,trap types,migration and accumulation characteristics,enrichment mechanisms,and reservoir formation models of ultra-deep water and ultra-shallow natural gas,taking the Lingshui 36-1 gas field as an example.(1)The genetic types of the ultra-deep water and ultra-shallow natural gas in the Qiongdongnan Basin include thermogenic gas and biogenic gas,and dominated by thermogenic gas.(2)The reservoirs are mainly composed of the Quaternary deep-water submarine fan sandstone.(3)The types of cap rocks include deep-sea mudstone,mass transport deposits mudstone,and hydrate-bearing formations.(4)The types of traps are mainly lithological,and also include structural-lithological traps.(5)The migration channels include vertical transport channels such as faults,gas chimneys,fracture zones,and lateral transport layers such as large sand bodies and unconformity surfaces,forming a single or composite transport framework.A new natural gas accumulation model is proposed for ultra-deep water and ultra-shallow layers,that is,dual source hydrocarbon supply,gas chimney and submarine fan composite migration,deep-sea mudstone-mass transport deposits mudstone-hydrate-bearing strata ternary sealing,late dynamic accumulation,and large-scale enrichment at ridges.The new understanding obtained from the research has reference and enlightening significance for the next step of deepwater and ultra-shallow layers,as well as oil and gas exploration in related fields or regions.
基金funded by the China Geological Survey(Grant Nos.DD20190379,DD20221695 and DD20221684)a collaboration program(2019-2024)between the Institute of Mineral Resources(Chinese Academy of Geological Sciences)and the Guangdong Dabaoshan Mining Co.,Ltd.
文摘The Dabaoshan porphyry Cu deposit(420 kilotons(kt)of Cu@0.36%)is located in South China.The newly discovered Cu orebodies are hosted in the dacite porphyry adjacent to a granodiorite porphyry.The alteration and mineralization timing and stages of the porphyry Cu deposit were not well-constrained.In this study,we combine field mapping,petrography,whole-rock geochemistry,hydrothermal rutile U-Pb dating and Cu isotopes to synthesize an ore model at Dabaoshan.In situ hydrothermal rutile U-Pb dating yields an age of 159±13 Ma,which brackets the timing of porphyry Cu mineralization.From top to bottom,the alteration zones in Dabaoshan are divided into quartz-sericite,biotite,chlorite-epidote,and chlorite-sericite subzones.Veins are classified into four stages(Stage 1 to 4)with Stage 4 quartz-sericite-chalcopyrite veins being the main Cu ore-bearing veins.The mineralized dacite porphyry has high SiO_(2),but low MgO,CaO,and Na_(2)O contents.The chalcopyrite hosted in veins exhibitsδ^(65)Cu=values ranging from−1.29‰to 0.51‰.Such copper isotope fractionation is attributed to vapor-brine phase separation,and mixing of fluids from different geochemical reservoirs.The timing of Cu mineralization and hydrothermal alteration support that the Jurassic granodiorite porphyry is an ore-forming intrusion at Dabaoshan.
基金The National Natural Science Foundation of China under contract No.42030502the Guangxi Scientific Projects under contract Nos.AD17129063,AA17204074,and 2025GXNSFAA069324the NSFC project under contract No.42166003。
文摘As one of the micro-blocks dispersed in the South China Sea(SCS),the Xisha Islands are covered by thick Cenozoic sedimentary layers,making it challenging to obtain magmatic rocks.Well CK-2 is a kilometer-scale scientific drilling project on the Xisha Islands in the northwestern SCS.It penetrates the thick reef limestone and reaches basaltic pyroclastic rocks.This study presents the whole-rock and olivine compositions of the basaltic volcaniclastic rocks from Well CK-2.These rocks exhibited ocean island basalt signatures characterized by the enrichment of light rare earth elements and high-field-strength elements.Compared with partial melting products derived from mantle peridotite,whole-rock compositions showed elevated Fe/Mn and Zn/Fe mass ratios.Additionally,olivines were characterized by a lower Ca content,higher Ni content,elevated Fe/Mn mass ratios,and moderate Mn/Zn mass ratios compared to those crystallized from peridotitic melts.The compositions of both the whole-rock and olivine phenocrysts indicate the presence of pyroxenite in the mantle source,which likely formed through the reaction of recycled oceanic crust with the surrounding mantle peridotite.Using the olivine-liquid Mg-Fe exchange thermometer,this study derived mantle potential temperatures(T_(p))ranging from 1502℃to 1756℃,which is consistent with those of plume-related ocean island basalts.Furthermore,the basaltic volcaniclastic rocks exhibit low H_(2)O contents(0.01%–1.47%),which were significantly lower than those found in the primary magmas of Large Igneous Provinces.These results suggest that the basaltic volcaniclastic rocks on the Xisha Islands originated from a volatile-poor mantle plume source.
