Drought across Northwest China in late spring has exerted a vital effect on the local climate and agricultural production,and has been alleviated during the past decades.This study explored the influence of the preced...Drought across Northwest China in late spring has exerted a vital effect on the local climate and agricultural production,and has been alleviated during the past decades.This study explored the influence of the preceding Arctic sea ice on the May drought in Northwest China caused by the precipitation deficit.Further analysis indicated that when the Greenland Sea ice concentration is abnormally high during February to April,the dry conditions in Northwest China tend to be alleviated.The increase of sea ice in the Greenland Sea can excite a meridional circulation,which causes sea surface temperature(SST)anomalies in the North Atlantic via the sea-air interaction,manifested as significant warm SST anomalies over the south of Greenland and the subtropical North Atlantic,but negative SST anomalies over the west of the Azores.This abnormal SST pattern maintains to May and triggers a zonal wave train from the North Atlantic through Scandinavia and Central Asia to Northwest China,leading to abnormal cyclones in Northwest China.Consequently,Northwest China experiences a more humid climate than usual.展开更多
“视域融合”强调翻译中理解与表达的互动,作为特殊的翻译模式,自译过程中需保持视域融合与分离的动态平衡。采用文献分析法,通过分析张爱玲自译本The rouge of the north中自译主体的视域融合与分离,旨在揭示自译过程中的动态平衡机制...“视域融合”强调翻译中理解与表达的互动,作为特殊的翻译模式,自译过程中需保持视域融合与分离的动态平衡。采用文献分析法,通过分析张爱玲自译本The rouge of the north中自译主体的视域融合与分离,旨在揭示自译过程中的动态平衡机制。张爱玲为提高自译本在目的语市场的接受度,对原作中的人物形象、情节走向、叙事手法等进行了调整,体现了自译者与原作的视域分离;原作中文化元素的再现以及创作风格的保留,体现了自译者与原作的视域融合。自译者通过协调视域交互,既忠实于原作又适应目的语市场,从而促进翻译作品跨文化传播。展开更多
Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addi...Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addition,to avoid the bias of detrital zircon ages caused by variations in zircon fertility,we collected 1709 whole rock zirconium content values(ppm)from granitic rocks with different ages in the North China Craton(NCC).Based on mean Zr content of granitic rocks in each age,these granitic rocks can be divided into four groups:Group A consists of Jurassic,Group B consists of Paleozoic,Neo-Mesoproterozoic and Neoarchean,Group C consists of Early Cretaceous and Triassic,and Group D consists of Paleoproterozoic.This research assigns to these groups zircon fertility factors(ZFF)of 1,1.4,1.8 and 2.2.The U-Pb age of detrital zircons from Late Jurassic sediments corrected by ZFF is statistically analyzed(K-S test,similarity,crosscorrelation,linkeness,and multidimensional scaling).And combining with paleocurrent and paleogeography,we construct two source-to-sink systems:(1)Jiaodong uplift and Sulu Orogenic Belt as the source area and the North Yellow Sea Basin as the sink area;(2)Liaodong Peninsula as the source area and the North Yellow Sea Basin as the sink area.展开更多
Although the late Quaternary slip rate of the Northern Margin Fault of the Huaizhuo Basin(NFHB)was studied approximately 30 years ago using thermoluminescence and geomorphic methods,the underlying uncertainty cannot b...Although the late Quaternary slip rate of the Northern Margin Fault of the Huaizhuo Basin(NFHB)was studied approximately 30 years ago using thermoluminescence and geomorphic methods,the underlying uncertainty cannot be neglected,considering the limitations resulting from age and displacement measurements.Accordingly,we attempted to re-estimate the late Quaternary slip rate of the NFHB using high-precision remote sensing image interpretation,large-scale geological and geomorphic mapping,paleoseismic analysis,and Quaternary geochronology testing.The results,based on stratigraphic dislocation and age constraint in the trenches,show that the present deformation of the NFHB has been dominated by the extension,with a vertical slip rate~0.04-0.11 mm/a.We estimate a vertical slip rate of~0.06 mm/a,with an R^(2) value of~0.91,which is much lower than the~0.5 mm/a result estimated previously.There are three possible reasons for this discrepancy.The first is the limitation resulting from dating and displacement measurements in earlier studies;the second is the slip decomposition caused by multiple branches of the NFHB,which leads to the low slip rate observed at a single fault;and third possible explanation is that the fault may be locked at present with a low slip rate,which means that the earthquake hazard of the NFHB cannot be ignored,and more in-depth research,such as geodetic and intensive observations of earthquake precursors,is urgently needed.This discovery poses a new challenge for the active study of the NFHB and the northeast corner of the Ordos Plateau in the North China Block.展开更多
Suid is one of the most common taxa among the Pleistocene mammalian fauna in China.However,its phylogenetic taxonomy and evolution are far from clear.The newly recovered suid fossil materials from the Early Pleistocen...Suid is one of the most common taxa among the Pleistocene mammalian fauna in China.However,its phylogenetic taxonomy and evolution are far from clear.The newly recovered suid fossil materials from the Early Pleistocene Shanshenmiaozui site in Nihewan Basin in North China provide new insight into the evolution of its kind in North China.The new materials include partial skulls and mandibles of males,and most of their teeth were preserved in situ.The specimens can be referred to the species Sus lydekkeri,which is the only species of Sus found in North China from the Early Pleistocene.The fossils of the once reported Pleistocene species“Potamochoerus chinhsienensis”should also be provisionally included in the species S.lydekkeri according to its form and size,which at least now excludes it from Potamochoerus.The species S.lydekkeri is very close to the extant species S.scrofa,and even was combined into the latter as a chronological subspecies by some authors,while its larger size,prominent preorbital fossa,backwardly positioned infraorbital foramen,frequently appearing verrucosic type(at least the intermediate type of the male lower canine),and simple crown structures support its validness as an independent species.The Early Pleistocene forms are characterized by a larger size,lower L/W ratio of cheekteeth,both upper and lower M3s having no more than three lobes,and the male lower canine is exclusively of a verrucosic type.Suid fossils are a very good indicator of paleoenvironments and paleoclimate.Both the northern and the southern faunas in China contain suid fossils throughout the Pleistocene Epoch,while the southern fauna has prominently more diversified taxa and more abundant fossil collections;whether that is caused by different origins or by environmental modifications is still not clear.展开更多
Mineralogical data are presented for the peridotite xenoliths from Miocene(~19 Ma)Qingyuan basalts in the eastern North China Craton(NCC),with the aim of constraining on property of the sub-continental lithospheric ma...Mineralogical data are presented for the peridotite xenoliths from Miocene(~19 Ma)Qingyuan basalts in the eastern North China Craton(NCC),with the aim of constraining on property of the sub-continental lithospheric mantle(SCLM)beneath the northern Tan-Lu fault zone(TLFZ)during the Cenozoic.The Qingyuan peridotites are dominated by spinel lherzolites with moderate-Mg^(#)olivines(89.4 to 91.2),suggesting that the regional SCLM is mainly transitional and fertile.Light rare earth element(LREE)-depleted,slightly depleted and enriched clinopyroxenes(Cpx)are identified in different peridotites.Chemical compositions of the LREE-enriched Cpx and the presence of phlogopite suggest that the Qingyuan SCLM has experienced silicate-related metasomatism.The synthesis of available mineral chemical data of the mantle xenoliths across the NCC confirms the SCLM beneath the NCC is highly heterogeneous in time and space.The Mesozoic–Cenozoic SCLM beneath the TLFZ and neighboring regions are more fertile and thinner than that beneath the region away from the fault zone.The fertile and refractory peridotite xenoliths experienced varying degrees of silicate and carbonatite metasomatism,respectively.The spatial-temporal lithospheric mantle heterogeneity in composition,age and thickness suggest that the trans-lithosphere fault zone played an important role in heterogeneous replacement of refractory cratonic lithospheric mantle.展开更多
How the subduction direction of the Paleo-Pacific plate beneath the Eurasian plate changes in the Early Cretaceous remains highly controversial due to the disappearance of the subducted oceanic plate.Intraplate deform...How the subduction direction of the Paleo-Pacific plate beneath the Eurasian plate changes in the Early Cretaceous remains highly controversial due to the disappearance of the subducted oceanic plate.Intraplate deformation structures in the east Asian continent,however,provide excellent opportunities for reconstructing paleostress fields in continental interior in relation to the Paleo-Pacific/Eurasian plate interaction.Anisotropy of magnetic susceptibility(AMS),geological,and geochronological analyses of post-kinematic mafic dykes intruding the detachment fault zone of the Wulian metamorphic core complex(WL MCC)in Jiaodong Peninsula exemplify emplacement of mantle-sourced dykes in a WNW-ESE(301°-121°)oriented tectonic extensional setting at ca.120 Ma.In combination with the results from our previous kinematic analysis of the MCC,a ca.21°clockwise change in the direction of intraplate extension is obtained for early(135-122 Ma)extensional exhumation of the MCC to late(122-108 Ma)emplacement of the dykes.Such a change is suggested to be related to the variation in subduction direction of the Paleo-Pacific plate beneath the Eurasian plate,from westward(pre-122 Ma)to west-northwestward(post-122 Ma).展开更多
In order to contribute to a better understanding of the biodiversity of local chicken populations, this study focused on the description of the essential qualitative parameters in the phenotypic characterization of lo...In order to contribute to a better understanding of the biodiversity of local chicken populations, this study focused on the description of the essential qualitative parameters in the phenotypic characterization of local species. Conducted in 6 localities in the Far North Region of Cameroon (Doukoula, Yagoua, Guidiguis, Dziguilao, Maroua 3rd and Méri), a population of 240 local chickens, including 172 hens and 68 cocks were characterized in family farms. The choice of localities was made on the basis of their strong potential local chicken flocks in the region. To this end, each animal was the subject of a qualitative description based on the identification of the sex of the animal, the description of the colorations of the plumage and extremities, and the description of the types of format, plumage and crests. All observations were made with the naked eye and in daylight and then photographed. The main results show that the plumage colors are multiple and dominated by the White-Pied-Black (21.7%) and the Mille-fleur (20.8%);the wattles are dominated by the red (60%) and the pink (35.4%);the tarsi are dominated by the white (43.8%) and the black (32.08%);the white skin (92.5%) dominates over the pink skin (7.5%);the “Smooth-uniform” feather is dominant (97.08%), followed by the smooth-crested type (2.08%) and the fries type (0.82%);the medium size of the chickens is dominant (86.66%), followed by the dwarf size (9.58%) and the large size (3.75%). The results of this study demonstrate that there is a strong phenotypic diversity within the local chicken population. This diversity can serve as a basis for the development of selection, conservation and genetic potential improvement programs based on rational exploitation of the local chicken.展开更多
The North Crimean Canal is a watercourse originating from the Kakhovka Reservoir and flowing into the Crimean Peninsula.The canal is an important source of drinking water supply and is also used to irrigate agricultur...The North Crimean Canal is a watercourse originating from the Kakhovka Reservoir and flowing into the Crimean Peninsula.The canal is an important source of drinking water supply and is also used to irrigate agricultural lands and fillfish farms.Due to its location,in recent years its functioning has not been stable,and the processes occurring along the canal have been poorly studied.In this study,we determined the content(with a safety assessment),features of spatial and seasonal distribution,and potential sources of hydrocarbons in the water of the North Crimean Canal,Crimea.During the study period(from March to November 2023)in the primary canal,the content of aliphatic hydrocarbons did not exceed sanitary standards(0.05 mg·L^(-1)).Their increased concentrations in the secondary canals could be associated with the input of organic substances into the canal water as it moves across the Crimean Peninsula.The composition of n-alkanes had temporal and spatial variability.In the period from spring to autumn,the content of autochthonous compounds decreased sharply.The share of allochthonous compounds increased as a consequence of the natural processes.The analysis of biogeochemical markers showed that autochthonous compounds produced by phytoplankton predominated in the spring–summer period.Subsequently,they had less importance,and the main share was accounted for allochthonous n-alkanes.展开更多
Numerous Indosinian igneous rocks in the North Qaidam(NQ)provide crucial insights into the tectonic evolution of the Paleo-Tethys Ocean.This paper presents a comprehensive study of the petrography,mineralogy,geochemis...Numerous Indosinian igneous rocks in the North Qaidam(NQ)provide crucial insights into the tectonic evolution of the Paleo-Tethys Ocean.This paper presents a comprehensive study of the petrography,mineralogy,geochemistry,zircon U-Pb geochronology,and Hf isotope composition of dioritic rocks from the eastern NQ.Zircon U-Pb dating results indicate that the dioritic rocks were formed during the Middle Triassic(244-240 Ma).The rocks exhibit high-K calc-alkaline characteristics with variable SiO_(2)(55.25-65.39 wt%)and elevated K_(2)O+Na_(2)O(4.81-6.94 wt%)contents.They show enrichment in LILEs(Rb,Ba,K)and depletion in HFSEs(Nb,Ta,Ti),with slight negative Eu anomalies(Eu/Eu*=0.89-0.97).Zirconε_(Hf)(t)values(−20.93 to+5.60)and T_(DM2)ages(0.85-1.72 Ga)suggest mixed sources.Petrographic and mineralogical analysis reveals that the plagioclase phenocrysts exhibit disequilibrium textures(including reverse zoning),primarily composed of andesine and labradorite,with a small amount of oligoclase.The clinopyroxenes are all augites and have high crystallization temperatures(1111-1151℃).These features,particularly the reverse zoning of plagioclase,support a petrogenetic model involving mantle-derived magma underplating that induced melting of ancient lower crust,followed by mixing of underplated basaltic magma with crust-derived felsic magma.Our results indicate formation in a back-arc extensional setting during subduction of the Zongwulong Paleo-Tethys Ocean.展开更多
The phenomenon of mud volcanism has a connection with the processes of hydrocarbon generation.However,the genesis of sediments is not often taken into consideration.The study of mud volcanoes in the West Kuban margina...The phenomenon of mud volcanism has a connection with the processes of hydrocarbon generation.However,the genesis of sediments is not often taken into consideration.The study of mud volcanoes in the West Kuban marginal marine basin and the Junggar freshwater basin revealed significant isotope-geochemical differences due to various types of sedimentation.The waters from both basins exhibit three principal geochemical facies:Na-HCO_(3),Na-Cl-HCO_(3),and Na-Cl,of which the latter type of water is the dominant.The analysis of genetic coefficients(Cl/Br,Na/Br,and B/Cl)allowed us to distinguish different pathways of mud volcanic water evolution:evaporite dissolution,formation(sedimentation)waters,and waters formed by active water-rock interaction.Through statistical research,we were able to determine that noticeable variations in the behavior of chemical elements in waters from different areas can reflect discrepancies in the geological environment and the evolutionary stage of the diagenetic water transformation.Using thermodynamic modeling,the main directions of mass transfer were shown.It was established that the waters of the Junggar Basin were at a relatively early stage of evolution and had reached equilibrium only with carbonates,while in the formation waters of the West Kuban Basin,element concentrations were also controlled by silicate minerals.The correlations betweenδ^(18)O andδ~2H values and saturation indices of halides,aluminosilicates,sulfates,and borates confirm the enrichment of water with heavy isotopes during interactions with rocks without evaporation or thermal water partition.These reactions are characterized by clay dehydration and water enrichment with^(18)O and B.The data obtained made it possible to clarify the depths of formation of mud-volcanic fluids and their possible stratigraphic sources.展开更多
This study presents LA–ICP–MS U–Pb dating and whole-rock geochemical analyses of the Late Triassic Gangshan harzburgite in the Qingyuan area,with the aim of elucidating its petrogenesis and further constraining the...This study presents LA–ICP–MS U–Pb dating and whole-rock geochemical analyses of the Late Triassic Gangshan harzburgite in the Qingyuan area,with the aim of elucidating its petrogenesis and further constraining the early Mesozoic tectonic evolution of the eastern segment of the northern margin of the North China Block(NCB).Zircons from the harzburgites exhibit typical oscillatory growth zoning or striped absorp-tion in cathodoluminescence images.U–Pb analyses of zircons yield ages ranging from 2525 Ma to 225 Ma,with two youngest ages(225±7 Ma)indicating that the harzburgites were formed during Late Triassic.Geochemical analyses of the Gangshan harzburgites show that the rocks have low concentrations of SiO_(2)(42.38%–42.85%)and Al_(2)O_(3)(3.31%–3.33%),along with high concentrations of MgO(41.32%–41.76%),Cr(4856×10^(-6)–5191×10^(-6))and Ni(1942×10^(-6)–2041×10^(-6)).They also display low REE abundances(∑REE=4.38×10^(-6)–4.69×10^(-6))and flat REE patterns with low(La/Yb)_(N) ratios(1.24–1.56)and slightly po-sitive Eu anomalies(δEu=1.13–1.16).These features suggest that the Gangshan harzburgites are cumulates of basaltic magma derived from the depleted lithospheric mantle.Combined with previous studies,these Late Triassic mafic–ultramafic rocks,together with coeval granitoids in adjacent regions,constitute a typical bimodal association,suggesting that they formed in a post-orogenic extensional environment after the final closure of the Paleo-Asian Ocean.展开更多
Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic ...Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic setting of the northeastern margin of the North China Craton(NCC).Here,we present U-Pb and Lu-Hf analyses of 712 detrital zircons,and U-Pb analyses of 347 detrital apatites from the Baifangzi,Diaoyutai and Qiaotou formations.The Baifangzi and Diaoyutai formations are dominated by Neoarchean(2.5-2.6 Ga)and Paleoproterozoic(1.8-1.9 Ga)zircons,indicating a predominant NCC provenance.The Qiaotou Formation is dominated by Mesoproterozoic(1.5-1.7 Ga and 1.1-1.3 Ga)zircons with mainly positiveεHf(t)values,which are similar to those from eastern Laurentia,implying a significant provenance transition.The detrital apatite age spectra of the Baifangzi and Diaoyutai Formations show major populations at 1.8-1.9 Ga and 1.1-1.3 Ga.Based on their trace element compositions,the Mesoproterozoic apatites were mainly sourced from metamorphic rocks,indicating regional metamorphism occurred in the NCC during 1.1-1.3 Ga.Combining these data with regional studies,we propose that the NCC was adjacent to eastern Laurentia during the assembly of the Rodinia supercontinent.展开更多
The Yishui complex,located in the western Shandong area of the North China Craton,is representative of the Archean crystalline basement of the North China Craton to explore the early tectonic-thermal evolution history...The Yishui complex,located in the western Shandong area of the North China Craton,is representative of the Archean crystalline basement of the North China Craton to explore the early tectonic-thermal evolution history of the Earth.Detailed petrography,mineral chemistry,metamorphic evolution and zircon U-Pb dating are presented for felsic granulite and two-pyroxene granulite from the Yishui complex to contribute to new insights into the Neoarchean tectonic evolution of the North China Craton.Three mineral assemblages are recognized for these granulite samples,including the prograde(M1),peak(M2)and retrograde(M3)mineral assemblages.Conventional geothermobarometry and phase equilibrium modeling yield P-T conditions of 6.5-10.9 kbar/718-839℃ for the peak metamorphism,which define a medium-pressure granulite-facies metamorphism occurred at middle to lower crust.Anticlockwise P-T paths with near-isobaric cooling(IBC)retrograde segments were reconstructed.Zircon LA-ICP-MS U-Pb dating suggests that the protolith of the felsic granulite was emplaced at 2541±7 Ma and the subsequent medium-pressure granulite-facies metamorphism occurred at 2518-2494 Ma.A two-stage mantle plume related crustal-scale sagduction geodynamic regime is proposed in the western Shandong terrane in the Neoarchean.展开更多
In the context of global warming, the increasing wildfire frequency has become a critical climate research focus in North America. This study used the Community Earth System Model(CESM 1.2) to investigate the impacts ...In the context of global warming, the increasing wildfire frequency has become a critical climate research focus in North America. This study used the Community Earth System Model(CESM 1.2) to investigate the impacts of 20thcentury wildfires on North American climate and hydrology. Summer represents the peak wildfire season in North America, with the Gulf of Mexico and Midwest regions experiencing the most severe effects. Wildfires not only damage vegetation during the fire season but also extend prolonged impacts into non-fire periods, showing distinct seasonal variations. In spring, wildfires increase surface albedo, triggering a cooling effect through enhanced snow cover and delayed snowmelt. Conversely, summer and autumn surface warming stems primarily from wildfire-suppressed vegetation transpiration. Warming near the Gulf of Mexico enhances moisture transport and precipitation, particularly in summer and autumn. Reduced evaporation and increased precipitation from the Gulf of Mexico significantly altered the hydrological cycle across North America, leading to increased runoff continent-wide.展开更多
Mountain front faults form the boundary between mountains and adjacent plains.These faults can propagate toward the plains and escalate the risk of seismic hazard for near cities.The North Tehran Fault(NTF)is a mounta...Mountain front faults form the boundary between mountains and adjacent plains.These faults can propagate toward the plains and escalate the risk of seismic hazard for near cities.The North Tehran Fault(NTF)is a mountain front fault bordering the Central Alborz with Tehran and Karaj plains.Structural and morphotectonic data from interpreted aerial photographs,satellite images,airborne geomagnetic data as well as field surveying have been used for detailed segmentation and evolution of the North Tehran Fault.This resulted in identification of the fault segments as the Niknamdeh,Darband,Darakeh-Garmdarreh,and Karaj from east to west.Active kinematics of these segments includes both thrusting and left-lateral components;but the dominant component is different among the segments.The Niknamdeh segment is connected to the Mosha Fault with a hard linkage,while its connection with the Darband segment is a widespread deformation zone.The connection zone between the Darband and Darakeh-Garmdarreh segments has the highest density of minor faults along the North Tehran Fault.The boundary of the Darakeh-Garmdarreh and Karaj segments is controlled by the F-3 transverse fault that has offset the NTF for~3 km right-laterally.The NTF has inverted from normal to dextral oblique fault in Miocene.The fault kinematics has changed from dextral to sinistral in Pliocene-Quaternary.Further regional oblique convergence resulted in minor fault reactivation such as relay ramp breaching faults,propagation of several footwall branches and hangingwall bypasses geometrical change of alluvial fans,and transfer of deformation front southwardly to the Tehran and Karaj plains.The findings of this paper are also applicable to other active oblique converging mountain fronts,inverted mountain front faults and the transition of deformation from these structures to the foreland basin.展开更多
The duration of the extratropical transition(ET)of tropical cyclones(TCs)is often closely associated with disaster intensity.Therefore,it is essential to understand the key factors that influence ET duration.Using the...The duration of the extratropical transition(ET)of tropical cyclones(TCs)is often closely associated with disaster intensity.Therefore,it is essential to understand the key factors that influence ET duration.Using the TC best-track data and reanalysis data,this study investigates the structural characteristics and key influencing factors of ET duration in the western North Pacific(WNP)during 1981–2022.Results show that,compared to TCs that undergo ET rapidly(≤12 h),TCs that experience ET slowly(≥24 h)undergo a more prolonged and complex ET process,maintaining a warm core and an upright structure for extended periods.By contrast,TCs undergoing rapid transition experience structural disintegration within 6–12 h after ET onset.Further analysis reveals that TCs with longer ET durations are characterized by stronger warm cores,more abundant moisture,weaker environmental vertical wind shear,slower translation speeds,and a longer residence time over warmer sea surface temperatures(SSTs),all of which support the maintenance of axisymmetric structures with strong warm cores.Environmental and structural factors,including cold-air intensity,vertical wind shear,TC translation speed,SST,relative humidity,TC intensity,the radius of 17 m s^(-1)wind,mean sea level pressure,and the radius of maximum wind,are found to exist significant correlation with ET duration.Cold-air intensity exhibited the highest correlation(r=–0.35),followed by TC translation speed and SST.A relative importance analysis shows that the environmental factors play a more substantial role than the internal TC structure,accounting for about 19.23%of the variance,with TC translation speed and cold-air effects explaining 11.68%.Based on the nine factors,a statistical forecasting model was developed,which shows considerable skill in predicting ET duration.展开更多
The Early Paleozoic porphyry-epithermal Au system of the Songshunangou District sits in the central segment of the North Qilian orogenic belt(NQOB).The porphyry Au mineralization is centered on the quartz diorite porp...The Early Paleozoic porphyry-epithermal Au system of the Songshunangou District sits in the central segment of the North Qilian orogenic belt(NQOB).The porphyry Au mineralization is centered on the quartz diorite porphyry(QDP),which is constrained to the Late Ordovician period.However,the geochemical signatures,the origin,and the tectonic setting of the QDP are not yet known and understood and are thus in the focus here.The QDP is a high-K calc-alkaline metaluminous rocks(K_(2)O+Na_(2)O:6.90-8.13;Al_(2)O_(3)/(CaO+Na_(2)O+K_(2)O):0.69-0.90)characterized by high(^(87)Sr/^(86)Sr)_(t)values(0.7093-0.7101)and lowε_(Nd)(t)values(-2.9 to-2.7)with corresponding T_(DM2)(Nd)ages of 1408 to 1430 Ma.Zirconε_(Hf)(t)values are low(-1.51 to+2.76)with corresponding T_(DM2)(Hf)ages of 1262 to 1533 Ma.The lead isotope values are 17.695-18.476 for(^(206)Pb/^(204)Pb)_(t),15.585-15.629 for(^(207)Pb/^(204)Pb)_(t),and 37.214-37.948 for(^(208)Pb/^(204)Pb)_(t).These data indicate that the QDP formed by the mixing of mantle-derived magmas(50%-70%)with lower crustal melts.The QDP is enriched in LREEs and LILE(Rb,Th,K)and is depleted in HFSE(Nb,Ta,Ti),expressing a clear volcanic arc affinity.High La and Th contents,and Zr/Y and Hf/Yb values suggest that the QDP formed in an Andean-type continental margin arc setting related to the northward subduction of the North Qilian oceanic slab.The Early Paleozoic subduction-related intermediate-acidic intrusions in NQOB have arc magma affinity,indicating that these rocks bear a great potential to discover further fertile porphyry deposits.展开更多
Original sedimentary manganese(Mn)deposits and supergene Mn ores are important Mn resources in China.However,the geochemical information from Chinese supergene Mn ores is scarce,and the relationship between sedimentar...Original sedimentary manganese(Mn)deposits and supergene Mn ores are important Mn resources in China.However,the geochemical information from Chinese supergene Mn ores is scarce,and the relationship between sedimentary Mn deposits and supergene Mn ores is ambiguous.In this study,we collected the original Mn-bearing dolomitic sandstones(ZK20-3 drillcore)and supergene Mn ores(Longmen Section)from eastern Hebei,North China for systematic petrographic,mineralogical and geochemical analyses.Our new data help us to figure out the transformation from original Mn-bearing deposits to supergene ores.The main minerals of original Mn-bearing dolomitic sandstones are quartz and feldspar,with minor muscovite,dolomite,rhodochrosite,ankerite,and kutnohorite.Supergene Mn-oxide ores only emerged in the middle part of the Longmen(LM)Section,and mainly contain quartz,pyrolusite,cryptomelane,todorokite and occasional dolomite.The possible transformation sequence of Mn minerals is:kutnohorite/rhodochrosite→pyrolusite(Ⅰ)→cryptomelane(todorokite)→todorokite(cryptomelane)→pyrolusite(Ⅱ).For Mn-oxide ores,Fe,Na and Si are enriched but Al,Ca,Mg and K are depleted with the enrichment of Mn.For original and supergene ores,the total rare earth element+ytterbium(∑REY)contents range from 105.68×10^(-6)to 250.56×10^(-6)and from 18.08×10^(-6)to 176.60×10^(-6),respectively.Original Mn ores have similar slightly LREE-enriched patterns,but the purer Mn-oxide ore shows a HREE-enriched pattern.In the middle part of the LM Section,positive Ce anomalies in Mn-oxide ores indicate the precipitation of Ce-bearing minerals.It implies the existence of geochemical barriers,which changed p H and Eh values due to the long-time influence of groundwater.展开更多
The North Sulawesi arc(NSUA)constitutes the northern arm of Sulawesi Island and is characterized by complex Cenozoic records of magmatism and tectonics.Zircon U-Pb geochronological and Hf-O isotopic data,whole-rock ma...The North Sulawesi arc(NSUA)constitutes the northern arm of Sulawesi Island and is characterized by complex Cenozoic records of magmatism and tectonics.Zircon U-Pb geochronological and Hf-O isotopic data,whole-rock major oxides,trace elemental,and Sr-Nd-Pb isotopic data of the high-silica granites from the NSUA document their petrogenesis and tectonic setting.Zircon elemental analysis of the granitic samples shows a juvenile oceanic crust origin and the U-Pb geochronology indicates their Oligocene ages between 30.4 and 27.3 Ma.The samples have high SiO_(2)(75.05 wt.%-79.38 wt.%)and Na_(2)O(4.48 wt.%-5.67 wt.%),low K_(2)O(0.15 wt.%-1.34 wt.%)and MgO(0.07 wt.%-0.91 wt.%)contents,belonging to calc-alkaline I-type high-silica granites.They have enriched LREE and LILE,and depleted HREE and HFSE,showing significant Eu,Sr,Nb,and Ta negative anomalies.These high-silica granites have low(^(87)Sr/^(86)Sr)_i ratios(0.704412-0.704592),positiveε_(Nd)(t)values(from+5.1 to+6.6),positive zirconε_(Hf)(t)values(from+10.1 to+18.8),low zirconδ^(18)O values(4.20‰-5.02‰),and similar Pb isotope compositions to the Indian Ocean MORB.Such signatures suggest that these high-silica granites were derived by partial melting process of the juvenile arc crust in an intra-oceanic setting.The felsic magmatism in the NSUA was likely driven by mantle upwelling and decompression melting during the Oligocene,in response to slab roll-back linked with the convergence of the East Sulawesi ophiolitic crust or the microcontinental fragments.展开更多
基金supported by the National Natural Science Foun-dation of China [grant numbers 41991281 and 42005028]。
文摘Drought across Northwest China in late spring has exerted a vital effect on the local climate and agricultural production,and has been alleviated during the past decades.This study explored the influence of the preceding Arctic sea ice on the May drought in Northwest China caused by the precipitation deficit.Further analysis indicated that when the Greenland Sea ice concentration is abnormally high during February to April,the dry conditions in Northwest China tend to be alleviated.The increase of sea ice in the Greenland Sea can excite a meridional circulation,which causes sea surface temperature(SST)anomalies in the North Atlantic via the sea-air interaction,manifested as significant warm SST anomalies over the south of Greenland and the subtropical North Atlantic,but negative SST anomalies over the west of the Azores.This abnormal SST pattern maintains to May and triggers a zonal wave train from the North Atlantic through Scandinavia and Central Asia to Northwest China,leading to abnormal cyclones in Northwest China.Consequently,Northwest China experiences a more humid climate than usual.
文摘“视域融合”强调翻译中理解与表达的互动,作为特殊的翻译模式,自译过程中需保持视域融合与分离的动态平衡。采用文献分析法,通过分析张爱玲自译本The rouge of the north中自译主体的视域融合与分离,旨在揭示自译过程中的动态平衡机制。张爱玲为提高自译本在目的语市场的接受度,对原作中的人物形象、情节走向、叙事手法等进行了调整,体现了自译者与原作的视域分离;原作中文化元素的再现以及创作风格的保留,体现了自译者与原作的视域融合。自译者通过协调视域交互,既忠实于原作又适应目的语市场,从而促进翻译作品跨文化传播。
基金supported by the National Natural Science Foundation of China(Nos.41872101 and 41790453-4)。
文摘Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addition,to avoid the bias of detrital zircon ages caused by variations in zircon fertility,we collected 1709 whole rock zirconium content values(ppm)from granitic rocks with different ages in the North China Craton(NCC).Based on mean Zr content of granitic rocks in each age,these granitic rocks can be divided into four groups:Group A consists of Jurassic,Group B consists of Paleozoic,Neo-Mesoproterozoic and Neoarchean,Group C consists of Early Cretaceous and Triassic,and Group D consists of Paleoproterozoic.This research assigns to these groups zircon fertility factors(ZFF)of 1,1.4,1.8 and 2.2.The U-Pb age of detrital zircons from Late Jurassic sediments corrected by ZFF is statistically analyzed(K-S test,similarity,crosscorrelation,linkeness,and multidimensional scaling).And combining with paleocurrent and paleogeography,we construct two source-to-sink systems:(1)Jiaodong uplift and Sulu Orogenic Belt as the source area and the North Yellow Sea Basin as the sink area;(2)Liaodong Peninsula as the source area and the North Yellow Sea Basin as the sink area.
基金The research and development project of Beijing Disaster Prevention Technology Co.,Ltd.(FZKJYF202201)funded this work.
文摘Although the late Quaternary slip rate of the Northern Margin Fault of the Huaizhuo Basin(NFHB)was studied approximately 30 years ago using thermoluminescence and geomorphic methods,the underlying uncertainty cannot be neglected,considering the limitations resulting from age and displacement measurements.Accordingly,we attempted to re-estimate the late Quaternary slip rate of the NFHB using high-precision remote sensing image interpretation,large-scale geological and geomorphic mapping,paleoseismic analysis,and Quaternary geochronology testing.The results,based on stratigraphic dislocation and age constraint in the trenches,show that the present deformation of the NFHB has been dominated by the extension,with a vertical slip rate~0.04-0.11 mm/a.We estimate a vertical slip rate of~0.06 mm/a,with an R^(2) value of~0.91,which is much lower than the~0.5 mm/a result estimated previously.There are three possible reasons for this discrepancy.The first is the limitation resulting from dating and displacement measurements in earlier studies;the second is the slip decomposition caused by multiple branches of the NFHB,which leads to the low slip rate observed at a single fault;and third possible explanation is that the fault may be locked at present with a low slip rate,which means that the earthquake hazard of the NFHB cannot be ignored,and more in-depth research,such as geodetic and intensive observations of earthquake precursors,is urgently needed.This discovery poses a new challenge for the active study of the NFHB and the northeast corner of the Ordos Plateau in the North China Block.
文摘Suid is one of the most common taxa among the Pleistocene mammalian fauna in China.However,its phylogenetic taxonomy and evolution are far from clear.The newly recovered suid fossil materials from the Early Pleistocene Shanshenmiaozui site in Nihewan Basin in North China provide new insight into the evolution of its kind in North China.The new materials include partial skulls and mandibles of males,and most of their teeth were preserved in situ.The specimens can be referred to the species Sus lydekkeri,which is the only species of Sus found in North China from the Early Pleistocene.The fossils of the once reported Pleistocene species“Potamochoerus chinhsienensis”should also be provisionally included in the species S.lydekkeri according to its form and size,which at least now excludes it from Potamochoerus.The species S.lydekkeri is very close to the extant species S.scrofa,and even was combined into the latter as a chronological subspecies by some authors,while its larger size,prominent preorbital fossa,backwardly positioned infraorbital foramen,frequently appearing verrucosic type(at least the intermediate type of the male lower canine),and simple crown structures support its validness as an independent species.The Early Pleistocene forms are characterized by a larger size,lower L/W ratio of cheekteeth,both upper and lower M3s having no more than three lobes,and the male lower canine is exclusively of a verrucosic type.Suid fossils are a very good indicator of paleoenvironments and paleoclimate.Both the northern and the southern faunas in China contain suid fossils throughout the Pleistocene Epoch,while the southern fauna has prominently more diversified taxa and more abundant fossil collections;whether that is caused by different origins or by environmental modifications is still not clear.
基金supported by funds from the Ministry of Science and Technology of the People's Republic of China(No.2019YFA0708603)NSFC(Nos.41973050,42288201,41930215)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0202)。
文摘Mineralogical data are presented for the peridotite xenoliths from Miocene(~19 Ma)Qingyuan basalts in the eastern North China Craton(NCC),with the aim of constraining on property of the sub-continental lithospheric mantle(SCLM)beneath the northern Tan-Lu fault zone(TLFZ)during the Cenozoic.The Qingyuan peridotites are dominated by spinel lherzolites with moderate-Mg^(#)olivines(89.4 to 91.2),suggesting that the regional SCLM is mainly transitional and fertile.Light rare earth element(LREE)-depleted,slightly depleted and enriched clinopyroxenes(Cpx)are identified in different peridotites.Chemical compositions of the LREE-enriched Cpx and the presence of phlogopite suggest that the Qingyuan SCLM has experienced silicate-related metasomatism.The synthesis of available mineral chemical data of the mantle xenoliths across the NCC confirms the SCLM beneath the NCC is highly heterogeneous in time and space.The Mesozoic–Cenozoic SCLM beneath the TLFZ and neighboring regions are more fertile and thinner than that beneath the region away from the fault zone.The fertile and refractory peridotite xenoliths experienced varying degrees of silicate and carbonatite metasomatism,respectively.The spatial-temporal lithospheric mantle heterogeneity in composition,age and thickness suggest that the trans-lithosphere fault zone played an important role in heterogeneous replacement of refractory cratonic lithospheric mantle.
基金supported by the National Natural Science Foundation of China(Grant Nos:42130801,41430211,90814006,and 42072226)the“Deep-time Digital Earth”Science and Technology Leading Talents Team Funds for the Central Universities for the Frontiers Science Center for Deep-time Digital Earth,CUGB(Fundamental Research Funds for the Central UniversitiesGrant No:2652023001).
文摘How the subduction direction of the Paleo-Pacific plate beneath the Eurasian plate changes in the Early Cretaceous remains highly controversial due to the disappearance of the subducted oceanic plate.Intraplate deformation structures in the east Asian continent,however,provide excellent opportunities for reconstructing paleostress fields in continental interior in relation to the Paleo-Pacific/Eurasian plate interaction.Anisotropy of magnetic susceptibility(AMS),geological,and geochronological analyses of post-kinematic mafic dykes intruding the detachment fault zone of the Wulian metamorphic core complex(WL MCC)in Jiaodong Peninsula exemplify emplacement of mantle-sourced dykes in a WNW-ESE(301°-121°)oriented tectonic extensional setting at ca.120 Ma.In combination with the results from our previous kinematic analysis of the MCC,a ca.21°clockwise change in the direction of intraplate extension is obtained for early(135-122 Ma)extensional exhumation of the MCC to late(122-108 Ma)emplacement of the dykes.Such a change is suggested to be related to the variation in subduction direction of the Paleo-Pacific plate beneath the Eurasian plate,from westward(pre-122 Ma)to west-northwestward(post-122 Ma).
文摘In order to contribute to a better understanding of the biodiversity of local chicken populations, this study focused on the description of the essential qualitative parameters in the phenotypic characterization of local species. Conducted in 6 localities in the Far North Region of Cameroon (Doukoula, Yagoua, Guidiguis, Dziguilao, Maroua 3rd and Méri), a population of 240 local chickens, including 172 hens and 68 cocks were characterized in family farms. The choice of localities was made on the basis of their strong potential local chicken flocks in the region. To this end, each animal was the subject of a qualitative description based on the identification of the sex of the animal, the description of the colorations of the plumage and extremities, and the description of the types of format, plumage and crests. All observations were made with the naked eye and in daylight and then photographed. The main results show that the plumage colors are multiple and dominated by the White-Pied-Black (21.7%) and the Mille-fleur (20.8%);the wattles are dominated by the red (60%) and the pink (35.4%);the tarsi are dominated by the white (43.8%) and the black (32.08%);the white skin (92.5%) dominates over the pink skin (7.5%);the “Smooth-uniform” feather is dominant (97.08%), followed by the smooth-crested type (2.08%) and the fries type (0.82%);the medium size of the chickens is dominant (86.66%), followed by the dwarf size (9.58%) and the large size (3.75%). The results of this study demonstrate that there is a strong phenotypic diversity within the local chicken population. This diversity can serve as a basis for the development of selection, conservation and genetic potential improvement programs based on rational exploitation of the local chicken.
基金This work has been supported by the Russian Science FoundationProject No.23-26-00128,“The role of the North Crimean Canal irrigation system in the processes of transfer of long-lived radionuclides of the Chernobyl origin,heavy metals,as well as hydrocarbons with the Dnieper water to the irrigated farmlands of Crimea”。
文摘The North Crimean Canal is a watercourse originating from the Kakhovka Reservoir and flowing into the Crimean Peninsula.The canal is an important source of drinking water supply and is also used to irrigate agricultural lands and fillfish farms.Due to its location,in recent years its functioning has not been stable,and the processes occurring along the canal have been poorly studied.In this study,we determined the content(with a safety assessment),features of spatial and seasonal distribution,and potential sources of hydrocarbons in the water of the North Crimean Canal,Crimea.During the study period(from March to November 2023)in the primary canal,the content of aliphatic hydrocarbons did not exceed sanitary standards(0.05 mg·L^(-1)).Their increased concentrations in the secondary canals could be associated with the input of organic substances into the canal water as it moves across the Crimean Peninsula.The composition of n-alkanes had temporal and spatial variability.In the period from spring to autumn,the content of autochthonous compounds decreased sharply.The share of allochthonous compounds increased as a consequence of the natural processes.The analysis of biogeochemical markers showed that autochthonous compounds produced by phytoplankton predominated in the spring–summer period.Subsequently,they had less importance,and the main share was accounted for allochthonous n-alkanes.
基金supported by China Geological Survey Project(DD20190069 and DD20221636)Science and Technology Plan Project in Shaanxi Province,China(2023-JC-ZD-14,2023-JC-YB-236,2024JC-YBQN-0249,and 2022JQ-286).
文摘Numerous Indosinian igneous rocks in the North Qaidam(NQ)provide crucial insights into the tectonic evolution of the Paleo-Tethys Ocean.This paper presents a comprehensive study of the petrography,mineralogy,geochemistry,zircon U-Pb geochronology,and Hf isotope composition of dioritic rocks from the eastern NQ.Zircon U-Pb dating results indicate that the dioritic rocks were formed during the Middle Triassic(244-240 Ma).The rocks exhibit high-K calc-alkaline characteristics with variable SiO_(2)(55.25-65.39 wt%)and elevated K_(2)O+Na_(2)O(4.81-6.94 wt%)contents.They show enrichment in LILEs(Rb,Ba,K)and depletion in HFSEs(Nb,Ta,Ti),with slight negative Eu anomalies(Eu/Eu*=0.89-0.97).Zirconε_(Hf)(t)values(−20.93 to+5.60)and T_(DM2)ages(0.85-1.72 Ga)suggest mixed sources.Petrographic and mineralogical analysis reveals that the plagioclase phenocrysts exhibit disequilibrium textures(including reverse zoning),primarily composed of andesine and labradorite,with a small amount of oligoclase.The clinopyroxenes are all augites and have high crystallization temperatures(1111-1151℃).These features,particularly the reverse zoning of plagioclase,support a petrogenetic model involving mantle-derived magma underplating that induced melting of ancient lower crust,followed by mixing of underplated basaltic magma with crust-derived felsic magma.Our results indicate formation in a back-arc extensional setting during subduction of the Zongwulong Paleo-Tethys Ocean.
基金partly supported by the NSFC-RSF Joint Research project(Nos.42261134534,23-47-00035)funded by the Chinese Academy of Sciences President’s International Fellowship Initiative(Nos.2024VCA0006,2024VCB0013)the National Natural Science Foundation of China(No.42442006)。
文摘The phenomenon of mud volcanism has a connection with the processes of hydrocarbon generation.However,the genesis of sediments is not often taken into consideration.The study of mud volcanoes in the West Kuban marginal marine basin and the Junggar freshwater basin revealed significant isotope-geochemical differences due to various types of sedimentation.The waters from both basins exhibit three principal geochemical facies:Na-HCO_(3),Na-Cl-HCO_(3),and Na-Cl,of which the latter type of water is the dominant.The analysis of genetic coefficients(Cl/Br,Na/Br,and B/Cl)allowed us to distinguish different pathways of mud volcanic water evolution:evaporite dissolution,formation(sedimentation)waters,and waters formed by active water-rock interaction.Through statistical research,we were able to determine that noticeable variations in the behavior of chemical elements in waters from different areas can reflect discrepancies in the geological environment and the evolutionary stage of the diagenetic water transformation.Using thermodynamic modeling,the main directions of mass transfer were shown.It was established that the waters of the Junggar Basin were at a relatively early stage of evolution and had reached equilibrium only with carbonates,while in the formation waters of the West Kuban Basin,element concentrations were also controlled by silicate minerals.The correlations betweenδ^(18)O andδ~2H values and saturation indices of halides,aluminosilicates,sulfates,and borates confirm the enrichment of water with heavy isotopes during interactions with rocks without evaporation or thermal water partition.These reactions are characterized by clay dehydration and water enrichment with^(18)O and B.The data obtained made it possible to clarify the depths of formation of mud-volcanic fluids and their possible stratigraphic sources.
基金Supported by projects of the National Natural Science Foundation of China(Nos.42372063,41722204).
文摘This study presents LA–ICP–MS U–Pb dating and whole-rock geochemical analyses of the Late Triassic Gangshan harzburgite in the Qingyuan area,with the aim of elucidating its petrogenesis and further constraining the early Mesozoic tectonic evolution of the eastern segment of the northern margin of the North China Block(NCB).Zircons from the harzburgites exhibit typical oscillatory growth zoning or striped absorp-tion in cathodoluminescence images.U–Pb analyses of zircons yield ages ranging from 2525 Ma to 225 Ma,with two youngest ages(225±7 Ma)indicating that the harzburgites were formed during Late Triassic.Geochemical analyses of the Gangshan harzburgites show that the rocks have low concentrations of SiO_(2)(42.38%–42.85%)and Al_(2)O_(3)(3.31%–3.33%),along with high concentrations of MgO(41.32%–41.76%),Cr(4856×10^(-6)–5191×10^(-6))and Ni(1942×10^(-6)–2041×10^(-6)).They also display low REE abundances(∑REE=4.38×10^(-6)–4.69×10^(-6))and flat REE patterns with low(La/Yb)_(N) ratios(1.24–1.56)and slightly po-sitive Eu anomalies(δEu=1.13–1.16).These features suggest that the Gangshan harzburgites are cumulates of basaltic magma derived from the depleted lithospheric mantle.Combined with previous studies,these Late Triassic mafic–ultramafic rocks,together with coeval granitoids in adjacent regions,constitute a typical bimodal association,suggesting that they formed in a post-orogenic extensional environment after the final closure of the Paleo-Asian Ocean.
基金financially supported by the National Natural Science Foundation of China(Grant No.41902224,41602209).
文摘Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic setting of the northeastern margin of the North China Craton(NCC).Here,we present U-Pb and Lu-Hf analyses of 712 detrital zircons,and U-Pb analyses of 347 detrital apatites from the Baifangzi,Diaoyutai and Qiaotou formations.The Baifangzi and Diaoyutai formations are dominated by Neoarchean(2.5-2.6 Ga)and Paleoproterozoic(1.8-1.9 Ga)zircons,indicating a predominant NCC provenance.The Qiaotou Formation is dominated by Mesoproterozoic(1.5-1.7 Ga and 1.1-1.3 Ga)zircons with mainly positiveεHf(t)values,which are similar to those from eastern Laurentia,implying a significant provenance transition.The detrital apatite age spectra of the Baifangzi and Diaoyutai Formations show major populations at 1.8-1.9 Ga and 1.1-1.3 Ga.Based on their trace element compositions,the Mesoproterozoic apatites were mainly sourced from metamorphic rocks,indicating regional metamorphism occurred in the NCC during 1.1-1.3 Ga.Combining these data with regional studies,we propose that the NCC was adjacent to eastern Laurentia during the assembly of the Rodinia supercontinent.
基金supported by the Natural Science Foundation of Shandong Provence(Grant No.ZR2023MD058)National Natural Science Foundation of China(Grant Nos.42072219,41802201)。
文摘The Yishui complex,located in the western Shandong area of the North China Craton,is representative of the Archean crystalline basement of the North China Craton to explore the early tectonic-thermal evolution history of the Earth.Detailed petrography,mineral chemistry,metamorphic evolution and zircon U-Pb dating are presented for felsic granulite and two-pyroxene granulite from the Yishui complex to contribute to new insights into the Neoarchean tectonic evolution of the North China Craton.Three mineral assemblages are recognized for these granulite samples,including the prograde(M1),peak(M2)and retrograde(M3)mineral assemblages.Conventional geothermobarometry and phase equilibrium modeling yield P-T conditions of 6.5-10.9 kbar/718-839℃ for the peak metamorphism,which define a medium-pressure granulite-facies metamorphism occurred at middle to lower crust.Anticlockwise P-T paths with near-isobaric cooling(IBC)retrograde segments were reconstructed.Zircon LA-ICP-MS U-Pb dating suggests that the protolith of the felsic granulite was emplaced at 2541±7 Ma and the subsequent medium-pressure granulite-facies metamorphism occurred at 2518-2494 Ma.A two-stage mantle plume related crustal-scale sagduction geodynamic regime is proposed in the western Shandong terrane in the Neoarchean.
基金National Natural Science Foundation of China(42175022)。
文摘In the context of global warming, the increasing wildfire frequency has become a critical climate research focus in North America. This study used the Community Earth System Model(CESM 1.2) to investigate the impacts of 20thcentury wildfires on North American climate and hydrology. Summer represents the peak wildfire season in North America, with the Gulf of Mexico and Midwest regions experiencing the most severe effects. Wildfires not only damage vegetation during the fire season but also extend prolonged impacts into non-fire periods, showing distinct seasonal variations. In spring, wildfires increase surface albedo, triggering a cooling effect through enhanced snow cover and delayed snowmelt. Conversely, summer and autumn surface warming stems primarily from wildfire-suppressed vegetation transpiration. Warming near the Gulf of Mexico enhances moisture transport and precipitation, particularly in summer and autumn. Reduced evaporation and increased precipitation from the Gulf of Mexico significantly altered the hydrological cycle across North America, leading to increased runoff continent-wide.
文摘Mountain front faults form the boundary between mountains and adjacent plains.These faults can propagate toward the plains and escalate the risk of seismic hazard for near cities.The North Tehran Fault(NTF)is a mountain front fault bordering the Central Alborz with Tehran and Karaj plains.Structural and morphotectonic data from interpreted aerial photographs,satellite images,airborne geomagnetic data as well as field surveying have been used for detailed segmentation and evolution of the North Tehran Fault.This resulted in identification of the fault segments as the Niknamdeh,Darband,Darakeh-Garmdarreh,and Karaj from east to west.Active kinematics of these segments includes both thrusting and left-lateral components;but the dominant component is different among the segments.The Niknamdeh segment is connected to the Mosha Fault with a hard linkage,while its connection with the Darband segment is a widespread deformation zone.The connection zone between the Darband and Darakeh-Garmdarreh segments has the highest density of minor faults along the North Tehran Fault.The boundary of the Darakeh-Garmdarreh and Karaj segments is controlled by the F-3 transverse fault that has offset the NTF for~3 km right-laterally.The NTF has inverted from normal to dextral oblique fault in Miocene.The fault kinematics has changed from dextral to sinistral in Pliocene-Quaternary.Further regional oblique convergence resulted in minor fault reactivation such as relay ramp breaching faults,propagation of several footwall branches and hangingwall bypasses geometrical change of alluvial fans,and transfer of deformation front southwardly to the Tehran and Karaj plains.The findings of this paper are also applicable to other active oblique converging mountain fronts,inverted mountain front faults and the transition of deformation from these structures to the foreland basin.
基金National Key R&D Program of China(2022YFC3004200)Science and Technology Commission of Shanghai Municipality,China(23DZ1204703)。
文摘The duration of the extratropical transition(ET)of tropical cyclones(TCs)is often closely associated with disaster intensity.Therefore,it is essential to understand the key factors that influence ET duration.Using the TC best-track data and reanalysis data,this study investigates the structural characteristics and key influencing factors of ET duration in the western North Pacific(WNP)during 1981–2022.Results show that,compared to TCs that undergo ET rapidly(≤12 h),TCs that experience ET slowly(≥24 h)undergo a more prolonged and complex ET process,maintaining a warm core and an upright structure for extended periods.By contrast,TCs undergoing rapid transition experience structural disintegration within 6–12 h after ET onset.Further analysis reveals that TCs with longer ET durations are characterized by stronger warm cores,more abundant moisture,weaker environmental vertical wind shear,slower translation speeds,and a longer residence time over warmer sea surface temperatures(SSTs),all of which support the maintenance of axisymmetric structures with strong warm cores.Environmental and structural factors,including cold-air intensity,vertical wind shear,TC translation speed,SST,relative humidity,TC intensity,the radius of 17 m s^(-1)wind,mean sea level pressure,and the radius of maximum wind,are found to exist significant correlation with ET duration.Cold-air intensity exhibited the highest correlation(r=–0.35),followed by TC translation speed and SST.A relative importance analysis shows that the environmental factors play a more substantial role than the internal TC structure,accounting for about 19.23%of the variance,with TC translation speed and cold-air effects explaining 11.68%.Based on the nine factors,a statistical forecasting model was developed,which shows considerable skill in predicting ET duration.
基金jointly funded by the National Natural Science Foundation of China(Nos.42230813,41972084)the National Key R&D Program of China(No.2022YFC2905000)the Everest Scientific Research Program of the Chengdu University of Technology(No.2020ZF11407)。
文摘The Early Paleozoic porphyry-epithermal Au system of the Songshunangou District sits in the central segment of the North Qilian orogenic belt(NQOB).The porphyry Au mineralization is centered on the quartz diorite porphyry(QDP),which is constrained to the Late Ordovician period.However,the geochemical signatures,the origin,and the tectonic setting of the QDP are not yet known and understood and are thus in the focus here.The QDP is a high-K calc-alkaline metaluminous rocks(K_(2)O+Na_(2)O:6.90-8.13;Al_(2)O_(3)/(CaO+Na_(2)O+K_(2)O):0.69-0.90)characterized by high(^(87)Sr/^(86)Sr)_(t)values(0.7093-0.7101)and lowε_(Nd)(t)values(-2.9 to-2.7)with corresponding T_(DM2)(Nd)ages of 1408 to 1430 Ma.Zirconε_(Hf)(t)values are low(-1.51 to+2.76)with corresponding T_(DM2)(Hf)ages of 1262 to 1533 Ma.The lead isotope values are 17.695-18.476 for(^(206)Pb/^(204)Pb)_(t),15.585-15.629 for(^(207)Pb/^(204)Pb)_(t),and 37.214-37.948 for(^(208)Pb/^(204)Pb)_(t).These data indicate that the QDP formed by the mixing of mantle-derived magmas(50%-70%)with lower crustal melts.The QDP is enriched in LREEs and LILE(Rb,Th,K)and is depleted in HFSE(Nb,Ta,Ti),expressing a clear volcanic arc affinity.High La and Th contents,and Zr/Y and Hf/Yb values suggest that the QDP formed in an Andean-type continental margin arc setting related to the northward subduction of the North Qilian oceanic slab.The Early Paleozoic subduction-related intermediate-acidic intrusions in NQOB have arc magma affinity,indicating that these rocks bear a great potential to discover further fertile porphyry deposits.
基金supported by the National Key R&D Program of China(No.2022YFF0800200)the NSFC(Nos.U1812402 and 42072131)+6 种基金Most Special Fund(No.MSFGPMR33)from the State Key Laboratory of GPMRthe CUG Scholar Scientific Research Funds(No.2022036)the NSF of Hebei Province(No.D2021334001)Research Project of Talent Engineering Training of Hebei Province(No.B2020005007)Research Project of Postdoctoral Scientific Research Station of HBGMR(No.454-0602-YBN-Z9E4)Natural Science Foundation of Hebei Province(No.D2021334001)the Central Government Guides Local Funds for Scientific and Technological Development(No.236Z7608 G)。
文摘Original sedimentary manganese(Mn)deposits and supergene Mn ores are important Mn resources in China.However,the geochemical information from Chinese supergene Mn ores is scarce,and the relationship between sedimentary Mn deposits and supergene Mn ores is ambiguous.In this study,we collected the original Mn-bearing dolomitic sandstones(ZK20-3 drillcore)and supergene Mn ores(Longmen Section)from eastern Hebei,North China for systematic petrographic,mineralogical and geochemical analyses.Our new data help us to figure out the transformation from original Mn-bearing deposits to supergene ores.The main minerals of original Mn-bearing dolomitic sandstones are quartz and feldspar,with minor muscovite,dolomite,rhodochrosite,ankerite,and kutnohorite.Supergene Mn-oxide ores only emerged in the middle part of the Longmen(LM)Section,and mainly contain quartz,pyrolusite,cryptomelane,todorokite and occasional dolomite.The possible transformation sequence of Mn minerals is:kutnohorite/rhodochrosite→pyrolusite(Ⅰ)→cryptomelane(todorokite)→todorokite(cryptomelane)→pyrolusite(Ⅱ).For Mn-oxide ores,Fe,Na and Si are enriched but Al,Ca,Mg and K are depleted with the enrichment of Mn.For original and supergene ores,the total rare earth element+ytterbium(∑REY)contents range from 105.68×10^(-6)to 250.56×10^(-6)and from 18.08×10^(-6)to 176.60×10^(-6),respectively.Original Mn ores have similar slightly LREE-enriched patterns,but the purer Mn-oxide ore shows a HREE-enriched pattern.In the middle part of the LM Section,positive Ce anomalies in Mn-oxide ores indicate the precipitation of Ce-bearing minerals.It implies the existence of geochemical barriers,which changed p H and Eh values due to the long-time influence of groundwater.
基金supported by the National Natural Science Foundation of China(No.42330302)the National Key Research and Development Program of China(No.2023YFF0803701)+1 种基金the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(No.SML2023SP206)the Australian Research Council(No.FL160100168)。
文摘The North Sulawesi arc(NSUA)constitutes the northern arm of Sulawesi Island and is characterized by complex Cenozoic records of magmatism and tectonics.Zircon U-Pb geochronological and Hf-O isotopic data,whole-rock major oxides,trace elemental,and Sr-Nd-Pb isotopic data of the high-silica granites from the NSUA document their petrogenesis and tectonic setting.Zircon elemental analysis of the granitic samples shows a juvenile oceanic crust origin and the U-Pb geochronology indicates their Oligocene ages between 30.4 and 27.3 Ma.The samples have high SiO_(2)(75.05 wt.%-79.38 wt.%)and Na_(2)O(4.48 wt.%-5.67 wt.%),low K_(2)O(0.15 wt.%-1.34 wt.%)and MgO(0.07 wt.%-0.91 wt.%)contents,belonging to calc-alkaline I-type high-silica granites.They have enriched LREE and LILE,and depleted HREE and HFSE,showing significant Eu,Sr,Nb,and Ta negative anomalies.These high-silica granites have low(^(87)Sr/^(86)Sr)_i ratios(0.704412-0.704592),positiveε_(Nd)(t)values(from+5.1 to+6.6),positive zirconε_(Hf)(t)values(from+10.1 to+18.8),low zirconδ^(18)O values(4.20‰-5.02‰),and similar Pb isotope compositions to the Indian Ocean MORB.Such signatures suggest that these high-silica granites were derived by partial melting process of the juvenile arc crust in an intra-oceanic setting.The felsic magmatism in the NSUA was likely driven by mantle upwelling and decompression melting during the Oligocene,in response to slab roll-back linked with the convergence of the East Sulawesi ophiolitic crust or the microcontinental fragments.
