The Gangdese belt in Xizang has experienced both Jurassic subduction and Cenozoic continental collision processes, making it a globally renowned region for magmatic rocks and porphyry copper deposits. Numerous Jurassi...The Gangdese belt in Xizang has experienced both Jurassic subduction and Cenozoic continental collision processes, making it a globally renowned region for magmatic rocks and porphyry copper deposits. Numerous Jurassic intrusions have been identified in the belt. Apart from the quartz diorite porphyry in the large Xietongmen deposit, the Cu mineralization potential of other Jurassic intrusions in this belt remains unclear. This study presents zircon U–Pb dating and trace elements, apatite major and trace elements as well as published whole-rock geochemical and isotopic data of the Dongga tonalite in the central part of the Gangdese belt, aiming to reveal the petrogenesis, oxidation state, volatile content, and Cu mineralization potential of this intrusion. The Dongga tonalite has a zircon U–Pb age of 179.4 ± 0.9 Ma. It exhibits high whole-rock V/Sc values(8.76–14.6), relatively low apatite CeN/CeN*ratios(1.04–1.28), elevated zircon(Eu/Eu*)Nvalues(an average of 0.44), high Ce4+/Ce3+values(205–1896), and high ?FMQ values(1.3–3.7), collectively suggesting a high magmatic oxygen fugacity. The Dongga tonalite features amphibole phenocrysts, relatively high whole-rock Sr/Y ratios(20.3–58.9), and lower zircon Ti temperatures (502–740 ℃), reflecting a high magmatic water content. Estimation of magmatic sulfur content(0.002–0.024 wt%) based on apatite SO3contents indicates an enriched magma sulfur content. Combined with previous studies and the collected Sr–Nd–Hf isotopes, the Dongga tonalite is derived from juvenile lower crust related with subduction of the Neo-Tethys oceanic slab. When compared with Xietongmen orebearing porphyries, the Dongga tonalite exhibits remarkable similarities with the Xietongmen ore-bearing porphyries in terms of magma source, tectonic background, magmatic redox state, and volatile components, which indicates that the Dongga tonalite has a high porphyry Cu mineralization potential, and therefore, provides important guidance for the future mineralization exploration.展开更多
Post-collisional magmatism contains important clues for understanding the reworking and growth of continental crust,as well as lithospheric delamination and orogenic collapse.Early Devonian magmatism has been identifi...Post-collisional magmatism contains important clues for understanding the reworking and growth of continental crust,as well as lithospheric delamination and orogenic collapse.Early Devonian magmatism has been identified in the North Qilian Orogenic Belt(NQOB).This paper reports an integrated study of petrology,whole-rock geochemistry,Sm-Nd isotope and zircon U-Pb dating,as well as Lu-Hf isotopic data,for two Early Devonian intrusive plutons.The Yongchang and Chijin granites yield zircon U-Pb ages of 394-407 Ma and 414 Ma,respectively.Both of them are characterized by weakly peraluminous to metaluminous without typical aluminium-rich minerals,LREE-enriched patterns with negative Eu anomalies and a negative correlation between P_(2)O_(5) and SiO_(2) contents,consistent with geochemical features of I-type granitoids.Zircons from the studied granites display negative to weak positive ε_(Hf)(t)values(−5.7 to 2.1),which agree well with those of negative ε_(Nd)(t)values(−6.4 to−2.9)for the whole-rock samples,indicating that they were derived from the partial melting of Mesoproterozoic crust.Furthermore,low Sr/Y ratios(1.13-21.28)and high zircon saturation temperatures(745℃ to 839℃,with the majority being>800℃)demonstrated a relatively shallow depth level below the garnet stability field and an additional heat source.Taken together,the Early Devonian granitic magmatism could have been produced by the partial melting of ancient crustal materials heated by mantle-derived magmas at high-temperature and low-pressure conditions during postcollisional extensional collapse.The data obtained in this study,when viewed in conjunction with previous studies,provides more information about the tectonic processes that followed the closure of the North Qilian Ocean.The tectonic transition from continental collision to post-collisional delamination could be constrained to~430 Ma,which is provided by the sudden decrease of Sr/Y and La/Yb ratios and an increase in zircon ε_(Hf)(t)values for granitoids.A two-stage tectonic evolution model from continental collision to post-collisional extensional collapse for the NQOB includes(a)continental collision and crustal thickening during ca.455-430 Ma,characterized by granulite-facies metamorphism and widespread low-Mg adakitic magmatism;(b)post-collisional delamination of thickened continental crust and extensional collapse of orogen during ca.430-390 Ma,provided by coeval high-Mg adakitic magmatism,A-type granites and I-type granitoids with low Sr-Y ratios.展开更多
Geodynamic mechanism responsible for the generation of Silurian granitoids and the tectonic evolution of the Qilian orogenic belt remains controversial. In this study, we report the results of zircon U–Pb age, and sy...Geodynamic mechanism responsible for the generation of Silurian granitoids and the tectonic evolution of the Qilian orogenic belt remains controversial. In this study, we report the results of zircon U–Pb age, and systematic whole-rock geochemical data for the Haoquangou and Liujiaxia granitoids within the North Qilian orogenic belt and the Qilian Block, respectively, to constrain their petrogenesis, and the Silurian tectonic evolution of the Qilian orogenic belt. Zircon U–Pb ages indicate that the Haoquangou and Liujiaxia intrusions were emplaced at423 ± 3 Ma and 432 ± 4 Ma, respectively. The Haoquangou granodiorites are calc-alkaline, while the Liujiaxia granites belong to the high-K calc-alkaline series.Both are peraluminous in composition and have relatively depleted Nd isotopic [ε_(Nd)(t) =(-3.9 – + 0.6)] characteristics compared with regional basement rocks, implying their derivation from a juvenile lower crust. They show adakitic geochemical characteristics and were generated by partial melting of thickened lower continental crust. Postcollisional extensional regime related to lithospheric delamination was the most likely geodynamic mechanism for the generation of the Haoquangou granodiorite, while the Liujiaxia granites were generated in a compressive setting during continental collision between the Qaidam and Qilian blocks.展开更多
This paper studied a snow event over North China on 21 February 2017,using aircraft in-situ data,a Lagrangian analysis tool,and WRF simulations with different microphysical schemes to investigate the supercooled layer...This paper studied a snow event over North China on 21 February 2017,using aircraft in-situ data,a Lagrangian analysis tool,and WRF simulations with different microphysical schemes to investigate the supercooled layer of warm conveyor belts(WCBs).Based on the aircraft data,we found a fine vertical structure within clouds in the WCB and highlighted a 1-2 km thin supercooled liquid water layer with a maximum Liquid Water Content(LWC) exceeding0.5 g kg^(-1) during the vertical aircraft observation.Although the main features of thermodynamic profiles were essentially captured by both modeling schemes,the microphysical quantities exhibited large diversity with different microphysics schemes.The conventional Morrison two-moment scheme showed remarkable agreement with in-situ observations,both in terms of the thermodynamic structure and the supercooled liquid water layer.However,the microphysical structure of the WCB clouds,in terms of LWC and IWC,was not apparent in HUJI fast bin scheme.To reduce such uncertainty,future work may focus on improving the representation of microphysics in bin schemes with in-situ data and using similar assumptions for all schemes to isolate the impact of physics.展开更多
The energy spectrum of energetic electrons is a key factor representing the dynamic variations of Earth’s Van Allen radiation belts.Increased measurements have indicated that the commonly used Maxwellian and Kappa di...The energy spectrum of energetic electrons is a key factor representing the dynamic variations of Earth’s Van Allen radiation belts.Increased measurements have indicated that the commonly used Maxwellian and Kappa distributions are inadequate for capturing the realistic spectral distributions of radiation belt electrons.Here we adopt the Kappa-type(KT)distribution as the fitting function and perform a statistical analysis to investigate the radiation belt electron flux spectra observed by the Van Allen Probes.By calculating the optimal values of the key KT distribution parameters(i.e.,κandθ2)from the observed spectral shapes,we fit the radiation belt electron fluxes at different L-shells under different geomagnetic conditions.In this manner,we obtain typical values of the KT distribution parameters,which are statistically feasible for modeling the radiation belt electron flux profiles during either geomagnetically quiet or active periods.A comparison of the KT distribution model results with those using the Maxwellian or Kappa distribution reveals the advantage of the KT distribution for studying the overall properties of the radiation belt electron spectral distribution,which has important implications for deepening the current understanding of the radiation belt electron dynamics under evolving geomagnetic conditions.展开更多
The Nianzi granite unit,which includes the Nianzi,Xiaolianghou and Xiawopu granitic intrusions,is a significant component of the northern part of the North China Craton(NCC)and is situated in the Yanshan fold and thru...The Nianzi granite unit,which includes the Nianzi,Xiaolianghou and Xiawopu granitic intrusions,is a significant component of the northern part of the North China Craton(NCC)and is situated in the Yanshan fold and thrust belt(YFTB).However,there is still debate regarding the tectonic evolutionary history of the YFTB during the late Permian to Triassic period,specifically regarding the timing of subduction and collision between the NCC and the Paleo-Asian Ocean.The Nianzi granite unit exhibits unique petrological,geochronological and geochemical signatures that shed light on the tectonic evolutionary history of the YFTB.This study presents detailed petrology,whole-rock geochemistry,together with Sr-Nd isotopic,zircon U-Pb dating and Lu-Hf isotopic data of the granites within the Nianzi granite unit.Our findings demonstrate that the granites primarily consist of subhedral K-feldspar,plagioclase,quartz,minor biotite and hornblende,with accessory titanite,apatite,magnetite and zircon.Zircon U-Pb dating indicates that the Xiaolianghou granite was emplaced at 247.5±0.62 Ma.Additionally,the adakitic characteristics of the Nianzi,Xiawopu and Xiaolianghou granitic intrusions,such as high Sr and Ba contents and high ratios of Sr/Y and(La/Yb)N,combined with negative Sr-Nd and Lu-Hf isotopes(87Sr/86Sr)i=0.705681–0.7057433,εNd(t)=−21.98 to−20.97,zirconεHf(t)=−20.26 to−9.92,as well as the I-type granite features of high SiO_(2),Na_(2)O and K_(2)O/Na_(2)O ratios,enriched Rb,K,Sr and Ba,along with depleted Th,U,Nb,Ta,P and Ti,suggest that the Nianzi granitic unit was mainly derived from the partial melting of a thickened lower crust containing hydrous,calc-alkaline to high-K calc-alkaline,mafic to intermediate metamorphic rocks.In light of these parameters,we further integrate our data with previous studies and conclude that the Nianzi granitic unit was generated in a post-collisional extensional environment during the Early Triassic.展开更多
Carbon peak and carbon neutrality(dual-carbon)are important targets for the international response to climate change.The Silk Road Economic Belt is a strategic resource region and is important for future ecological en...Carbon peak and carbon neutrality(dual-carbon)are important targets for the international response to climate change.The Silk Road Economic Belt is a strategic resource region and is important for future ecological environment and tourism development.Based on the“dual-carbon”targets,the Single index quantification,Multiple index synthesis,and Poly-criteria integration evaluation model were used in this study to measure the coordinated development index of the ecological environment,public service,and tourism economy along the Silk Road Economic Belt and to analyze its spatial and temporal evolution.Further,it explores the dynamic evolution and development trend of the three systems using the Kernel Density and Grey Markov Prediction Model.The results show that the coordinated development index along this region needs to be improved during the study period.Furthermore,the coordinated development index of the Southwest region is relatively higher than that of the Northwest region.From the development trend of the three systems,all of them develop in a stable manner;however,the tourism economy system is easily affected by external disturbances.The coordinated development index of the three systems changes dynamically and tends to be in a good state of coordination.There is a certain spatial and temporal heterogeneity.The gravity center of the coordinated development index has been in the Southwest region.During the forecast period,the coordinated development index along this region will improve significantly,while insufficient and unbalanced development will continue.展开更多
BACKGROUND Colorectal cancer(CRC)plays a significant role in morbidity,mortality,and economic cost in the Belt and Road Initiative(“B and R”)countries.In addition,these countries have a substantial consumption of pr...BACKGROUND Colorectal cancer(CRC)plays a significant role in morbidity,mortality,and economic cost in the Belt and Road Initiative(“B and R”)countries.In addition,these countries have a substantial consumption of processed meat.However,the burden and trend of CRC in relation to the consumption of a diet high in processed meat(DHPM-CRC)in these“B and R”countries remain unknown.AIM To analyze the burden and trend of DHPM-CRC in the“B and R”countries from 1990 to 2019.METHODS We used the 2019 Global Burden of Disease Study to collate information regarding the burden of DHPM-CRC.Numbers and age-standardized rates(ASRs)of deaths along with the disability-adjusted life years(DALYs)were determined among the“B and R”countries in 1990 and 2019.Using joinpoint regression analysis,the average annual percent change(AAPC)was used to analyze the temporal trends of age-standardized DALYs rate(ASDALR)from 1990 to 2019 and in the final decade(2010–2019).RESULTS We found geographical differences in the burden of DHPM-CRC among“B and R”countries,with the three highest-ranking countries being the Russian Federation,China,and Ukraine in 1990,and China,the Russian Federation,and Poland in 2019.The burden of DHPM-CRC generally increased in most member countries from 1990 to 2019(all P<0.05).The absolute number of deaths and DALYs in DHPM-CRC were 3151.15[95%uncertainty interval(UI)665.74-5696.64]and 83249.31(95%UI 15628.64-151956.31)in China in 2019.However,the number of deaths(2627.57-2528.51)and DALYs(65867.39-55378.65)for DHPM-CRC in the Russian Federation has declined.The fastest increase in ASDALR for DHPM-CRC was observed in Vietnam,Southeast Asia,with an AAPC value of 3.90%[95%confidence interval(CI):3.63%-4.16%],whereas the fastest decline was observed in Kyrgyzstan,Central Asia,with an AAPC value of-2.05%(95%CI:-2.37%to-1.73%).A substantial upward trend in ASR of mortality,years lived with disability,years of life lost,and DALYs from DHPM-CRC changes in 1990-2019 and the final decade(2010-2019)for most Maritime Silk Route members in East Asia,South Asia,Southeast Asia,North Africa,and the Middle East,as well as Central Europe,while those of the most Land Silk Route members in Central Asia and Eastern Europe have decreased markedly(all P<0.05).The ASDALR for DHPM-CRC increased more in males than in females(all P<0.05).For those aged 50-74 years,the ASDALR for DHPM-CRC in 40 members exhibited an increasing trend,except for 20 members,including 7 members in Central Asia,Maldives,and 12 high or high-middle social development index(SDI)members in other regions(all P<0.05).CONCLUSION The burden of DHPM-CRC varies substantially across“B and R”countries and threatens public health.Relevant evidence-based policies and interventions tailored to the different trends of countries in SDIs or Silk Routes should be adopted to reduce the future burden of CRC in“B and R”countries via extensive collaboration.展开更多
A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics...A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics of the frontal and warm sector rain belts that occurred in South China on May 10–13,2022.The southern rain belt occurred in an environment with favorable mesoscale conditions but weak large-scale forcing.In contrast,the northern rain belt was related to low-level horizontal shear and the surface-level front.The interaction between the enhanced southeasterly winds and the rainfall-induced cold pool promoted the persistent growth of convection along the southern rain belt.The convective cell propagated east over the coastal area,where there was a large temperature gradient.The bow-shaped echo in this region may be closely related to the rear-inflow jet.By contrast,the initial convection of the northern rain belt was triggered along the front and the region of low-level horizontal shear,with mesoscale interactions between the enhanced warm-moist southeasterly airflow and the cold dome associated with the earlier rain.The terrain blocked the movement of the cold pool,resulting in the stagnation of the frontal convective cell at an early stage.Subsequently,a meso-γ-scale vortex formed during the rapid movement of the convective cell,corresponding to an enhancement of precipitation.The representative raindrop spectra for the southern rain belt were characterized by a greater number and higher density of raindrops than the northern rain belt,even though both resulted in comparable hourly rainfalls.These results help us better understand the characteristics of double rain belts over South China.展开更多
Accelerating the construction of agricultural power,further promoting the high-quality development of the Yangtze River Economic Belt,and better supporting and serving Chinese-style modernization are the key issues at...Accelerating the construction of agricultural power,further promoting the high-quality development of the Yangtze River Economic Belt,and better supporting and serving Chinese-style modernization are the key issues at present.This paper first introduces the Yangtze River Economic Belt and its ethnic areas,and studies the characteristics of the grain and oil industry in the ethnic autonomous areas of the economic belt,as well as the current situation of various types of intellectual property resources,such as industrial cultural heritage,scientific and tech-nological innovation,and brand marking intellectual property.Besides,it analyzes the main problems in the high-quality development of grain and oil in the Yangtze River Economic Belt ethnic areas.Finally,it comes up with recommendations,including protecting the intellectual prop-erty rights of cultural heritage in the field of grain and oil,leading the inheritance and development of excellent traditional Chinese culture,use scientific and technological innovation intellectual property rights to promote the innovation-driven development strategy of the grain and oil in-dustry,and providing counterpart assistance to ethnic autonomous areas in the Yangtze River Economic Belt to further promote the high-quality development of the Yangtze River Economic Belt.展开更多
This study employs Norman Fairclough’s Critical Discourse Analysis(CDA)three-dimensional model,using the Republic of Kazakhstan as a case study,to delve into the discourse construction of China’s Belt and Road Initi...This study employs Norman Fairclough’s Critical Discourse Analysis(CDA)three-dimensional model,using the Republic of Kazakhstan as a case study,to delve into the discourse construction of China’s Belt and Road Initiative(BRI)in Central Asian countries.Through detailed analysis of policy documents,media reports,and public discussions in Central Asian countries,this paper reveals how the BRI constructs specific social practices,discourse events,and textual meanings within these nations.The findings indicate that through this global development strategy,China has not only strengthened its economic ties with Central Asian countries but has also exerted profound influences on political,cultural,and social levels.展开更多
Using the data of drilling, logging, core, experiments and production, the heterogeneity and differential hydrocarbon accumulation model of deep reservoirs in Cretaceous Qingshuihe Formation(K1q) in the western sectio...Using the data of drilling, logging, core, experiments and production, the heterogeneity and differential hydrocarbon accumulation model of deep reservoirs in Cretaceous Qingshuihe Formation(K1q) in the western section of the foreland thrust belt in southern Junggar Basin are investigated. The target reservoirs are characterized by superimposition of conglomerates, sandy conglomerates and sandstones, with high content of plastic clasts. The reservoir space is mainly composed of intergranular pores. The reservoirs are overall tight, and the sandy conglomerate has the best physical properties. The coupling of short deep burial period with low paleotemperature gradient and formation overpressure led to the relatively weak diagenetic strength of the reservoirs. Specifically, the sandy conglomerates show relatively low carbonate cementation, low compaction rate and high dissolution porosity. The special stress-strain mechanism of the anticline makes the reservoirs at the top of the anticline turning point more reformed by fractures than those at the limbs, and the formation overpressure makes the fractures in open state. Moreover, the sandy conglomerates have the highest oil saturation. Typical anticline reservoirs are developed in deep part of the thrust belt, but characterized by "big trap with small reservoir". Significantly, the sandy conglomerates at the top of anticline turning point have better quality, lower in-situ stress and higher structural position than those at the limbs,with the internal hydrocarbons most enriched, making them high-yield oil/gas layers. The exponential decline of fractures makes hydrocarbon accumulation difficult in the reservoirs at the limbs. Nonetheless, plane hydrocarbon distribution is more extensive at the gentle limb than the steep limb.展开更多
The North Qinling Orogenic Belt(NQOB)is a composite orogenic belt in central China.It started evolving during the Meso-Neoproterozoic period and underwent multiple stages of plate subduction and collision before enter...The North Qinling Orogenic Belt(NQOB)is a composite orogenic belt in central China.It started evolving during the Meso-Neoproterozoic period and underwent multiple stages of plate subduction and collision before entering intra-continental orogeny in the Late Triassic.The Meso-Cenozoic intra-continental orogeny and tectonic evolution had different responses in various terranes of the belt,with the tectonic evolution of the middle part of the belt being particularly controversial.The granites distributed in the Dayu and Kuyu areas in the middle part of the NQOB can provide an important window for revealing the geodynamic mechanisms of the NQOB.The main lithology of Dayu and Kuyu granites is biotite monzogranite,and the zircon U-Pb dating yielded intrusive ages of 151.3±3.4 Ma and 147.7±1.5 Ma,respectively.The dates suggest that the biotite monzogranite were formed at the end of the Late Jurassic.The whole-rock geochemistry analysis shows that the granites in the study areas are characterized by slightly high SiO_(2)(64.50-68.88 wt%)and high Al_(2)O_(3)(15.12-16.24 wt%)and Na_(2)O(3.55-3.80 wt%)contents.They are also enriched in light rare earth elements,large ion lithophile elements(e.g.,Ba,K,La,Pb and Sr),and depleted in high field strength elements(HFSEs)(e.g.,Ta,Nb,P and Ti).Additionally,the granites have weakly negative-slightly positive Eu anomalies(δEu=0.91-1.19).Zircon Lu-Hf isotopic analysis showedε_(Hf)(t)=-6.1--3.8,and the two-stage model age is T_(2DM(crust))=1.5-1.6 Ga.The granites in the study areas are analyzed as weak peraluminous high-K calc-alkaline I-type granites.They formed by partial melting of the thickened ancient lower crust,accompanied by the addition of minor mantle-derived materials.During magma ascent,they experienced fractional crystallization,with residual garnet and amphibole for a certain proportion in the magma source region.Comprehensive the geotectonic data suggest that the end of the Late Jurassic granite magmatism in the Dayu and Kuyu areas represents a compression-extension transition regime.It may have been a response to multiple tectonic mechanisms,such as the late Mesozoic intra-continental southward subduction of the North China Craton and the remote effect of the Paleo-Pacific Plate subduction.展开更多
The current research of abrasive belt grinding rail mainly focuses on the contact mechanism and structural design.Compared with the closed structure abrasive belt grinding,open-structured abrasive belt grinding has ex...The current research of abrasive belt grinding rail mainly focuses on the contact mechanism and structural design.Compared with the closed structure abrasive belt grinding,open-structured abrasive belt grinding has excellent performance in dynamic stability,consistency of grinding quality,extension of grinding mileage and improvement of working efficiency.However,in the contact structure design,the open-structured abrasive belt grinding rail using a profiling pressure grinding plate and the closed structure abrasive belt using the contact wheel are different,and the contact mechanisms of the two are different.In this paper,based on the conformal contact and Hertz theory,the contact mechanism of the pressure grinding plate,abrasive belt and rail is analyzed.Through finite element simulation and static pressure experiment,the contact behavior of pressure grinding plate,abrasive belt and rail under single concentrated force,uniform force and multiple concentrated force was studied,and the distribution characteristics of contact stress on rail surface were observed.The results show that under the same external load,there are three contact areas under the three loading modes.The outer contour of the middle contact area is rectangular,and the inner contour is elliptical.In the contact area at both ends,the stress is extremely small under a single concentrated force,the internal stress is drop-shaped under a uniform force,and the internal stress under multiple concentration forces is elliptical.Compared with the three,the maximum stress is the smallest and the stress distribution is more uniform under multiple concentrated forces.Therefore,the multiple concentrated forces is the best grinding pressure loading mode.The research provides support for the application of rail grinding with open-structured abrasive belt based on pressure grinding plate,such as contact mechanism and grinding pressure mode selection.展开更多
Gneisses with anatectic characteristics from the Liansan island in the Sulu UHPM(ultra-high pressure metamorphic)belt were studied for petrography,titanite U-Pb dating and mineral geochemistry.Three origins of garnets...Gneisses with anatectic characteristics from the Liansan island in the Sulu UHPM(ultra-high pressure metamorphic)belt were studied for petrography,titanite U-Pb dating and mineral geochemistry.Three origins of garnets are distinguished:metamorphic garnet,peritectic garnet and anatectic garnet,which are formed in the stages of peak metamorphism,retrograde anatexis and melt crystallization,respectively.The euhedral titanite has a high content of REE and high Th/U ratios,which is interpreted as indicating that it was newly-formed from an anatectic melt.The LA-ICP-MS titanite U-Pb dating yields 214-217 Ma ages for the titanite(melt)crystallization.The distribution of trace elements varies in response to the different host minerals at different stages.At the peak metamorphic stage,Y and HREE are mainly hosted by garnet,Ba and Rb by phengite,Sr,Nb,Ta,Pb,Th,U and LREE by allanite and Y,U and HREE by zircon.During partial melting,Y,Pb,Th,U and REE are released into the melt,which causes a dramatic decline of these element contents in the retrograde minerals.Finally,titanite absorbs most of the Nb,U,LREE and HREE from the melt.Therefore,the different stages of metamorphism have different mineral assemblages,which host different trace elements.展开更多
Sea area is an important area of oil and gas exploration in China.It has been found that China's sea area mainly consists of coal type oil and gas,and the exploration of coal-bearing series source rocks has become...Sea area is an important area of oil and gas exploration in China.It has been found that China's sea area mainly consists of coal type oil and gas,and the exploration of coal-bearing series source rocks has become an important part of oil and gas exploration there.Through years of comprehensive geological research in China's sea area,it has been revealed that it has undergone multiple occurrences of tectonic opening and closing movements in varying degrees in the Paleogene,forming 26 Cenozoic sedimentary basins of various types,such as active continental margin,passive continental margin,transitional continental margin and drift rift basins.In the present study,it is observed for the first time that coal type source rocks are mainly developed in 14 continental margin basins in China's sea area,revealing that a very large C-shaped coal-bearing basin group developed there in the Cenozoic.Next,based on the coupling analysis of paleoclimate,paleobotany,paleogeography and paleostructure,it is observed that there are five coal-forming periods in China's sea area,namely the Paleocene,Eocene,early Oligocene,late Oligocene and Miocene-Pliocene,and the coal-forming age is gradually new from north to south.It is also found that the coal seams in the sea area are mainly developed in three coal-forming environments in Cenozoic,namely delta,fan delta and tidal flat-lagoon.The coal seams developed in different environments are characterized by thin thickness,many layers and poor stability.However,the coal-bearing series source rocks in China's sea area have a wide distribution range,very high thickness and large amount,thus forming a material basis for the formation of rich coal type oil and gas.展开更多
In the second member of the Upper Triassic Xujiahe Formation(T_(3)x_(2))in the Xinchang area,western Sichuan Basin,only a low percent of reserves has been recovered,and the geological model of gas reservoir sweet spot...In the second member of the Upper Triassic Xujiahe Formation(T_(3)x_(2))in the Xinchang area,western Sichuan Basin,only a low percent of reserves has been recovered,and the geological model of gas reservoir sweet spot remains unclear.Based on a large number of core,field outcrop,test and logging-seismic data,the T_(3)x_(2) gas reservoir in the Xinchang area is examined.The concept of fault-fold-fracture body(FFFB)is proposed,and its types are recognized.The main factors controlling fracture development are identified,and the geological models of FFFB are established.FFFB refers to faults,folds and associated fractures reservoirs.According to the characteristics and genesis,FFFBs can be divided into three types:fault-fracture body,fold-fracture body,and fault-fold body.In the hanging wall of the fault,the closer to the fault,the more developed the effective fractures;the greater the fold amplitude and the closer to the fold hinge plane,the more developed the effective fractures.Two types of geological models of FFFB are established:fault-fold fracture,and matrix storage and permeability.The former can be divided into two subtypes:network fracture,and single structural fracture,and the later can be divided into three subtypes:bedding fracture,low permeability pore,and extremely low permeability pore.The process for evaluating favorable FFFB zones was formed to define favorable development targets and support the well deployment for purpose of high production.The study results provide a reference for the exploration and development of deep tight sandstone oil and gas reservoirs in China.展开更多
We investigated the meta-gabbronorites in Liangcheng and used detailed petrography,geochemistry,zircon geochronological and in-situ Hf isotopic studies to clarify their formation and metamorphic ages,petrogenesis,tect...We investigated the meta-gabbronorites in Liangcheng and used detailed petrography,geochemistry,zircon geochronological and in-situ Hf isotopic studies to clarify their formation and metamorphic ages,petrogenesis,tectonic setting and provide constraints on the tectonic evolution of Khondalite Belt(KB).The zircon U-Pb dating results show that the meta-gabbronorites crystallized at~1.94 Ga and were metamorphosed at~1.91–1.89 Ga.They can be subdivided into the low-Mg and high-Mg groups.The low-Mg meta-gabbronorites contain relatively lower MgO and higher SiO2 contents than high-Mg meta-gabbronorites.They are enriched in light rare earth elements and large ion lithophile elements,depleted in high field strength elements,and exhibit positive(high-Mg meta-gabbronorites)and negative(low-Mg metagabbronorites)Sr and Eu anomalies.The zircon in-situεHf(t)of meta-gabbronorites is 0.07–4.12,with Hf model ages(TDM)of 2169–2400 Ma.The meta-gabbronorites in Liangcheng originated from the asthenospheric mantle and experienced fractional crystallization of olivine,orthopyroxene,clinopyroxene,and plagioclase.They were contaminated by the crustal rocks(mainly khondalite series)during ascent,especially for low-Mg gabbronorites.The ridge subduction is the most plausible tectonic setting for meta-gabbronorites,indicating the eastern segment of KB was in a ridge subduction setting at~1.94 Ga following an orogenic thickening event during a prolonged orogenic process.展开更多
The dimensions and connectivity of fluvial reservoirs vary greatly, making it challenging to characterize them using conventional approaches. In this study integrated channel belt dimension analysis from seismic geomo...The dimensions and connectivity of fluvial reservoirs vary greatly, making it challenging to characterize them using conventional approaches. In this study integrated channel belt dimension analysis from seismic geomorphology and empirical equations, well log facies, and petrophysical analysis were performed to characterize the fluvial reservoirs. The study interval consists of fluvial deposits and is divided into three reservoir zones, which are defined by four key regional markers (B, D, K, O). In these intervals, six (6) fluvial facies have been identified. Based on the log facies proportions and their stacking relationships, it is interpreted that the reservoirs in zone 1 (B to D) were deposited in a proximal reach of a meandering system, zone 2 (D to K) in a marginal marine setting, and zone 3 (K) in a distal reach of a meandering system. The dimensions of fluvial channels and channel belts were determined using empirical equations. The results were compared with the observed dimensions of fluvial channels and channel belts from the seismic horizon and stratal slices of the same intervals. Zones 1 and 3 are characterized by broad meander belts (1000–4000 m) compared to zone 2 (600–1300 m). Petrophysical analysis showed zones 1 and 3 have the better petrophysical properties compared to zone 2. Though zone 3 has the most well-developed sand bodies, the best reservoir interval is zone 1 because of its higher porosity. Although channel belt dimensions have a significant influence on reservoir connectivity, they do not seem to have control on reservoir properties. The channel belt dimensions obtained from the empirical equations and interpreted from the seismic geomorphology analysis were found to be strikingly similar. Since three-dimensional seismic data is not available everywhere and seismic imaging quality decreases with depth, empirical equations can be used to analyze fluvial reservoir parameters and their connectivity at greater depths.展开更多
基金supported by the National Natural Science Foundation Program of China(42102095,42362013,42363009)the Jiangxi Provincial Natural Science Foundation(20224BAB203036,20224BAB213040,20224ACB203008)the Open Research Fund Program of State Key Laboratory of Nuclear Resources and Environment,East China University of Technology(2022NRE12).
文摘The Gangdese belt in Xizang has experienced both Jurassic subduction and Cenozoic continental collision processes, making it a globally renowned region for magmatic rocks and porphyry copper deposits. Numerous Jurassic intrusions have been identified in the belt. Apart from the quartz diorite porphyry in the large Xietongmen deposit, the Cu mineralization potential of other Jurassic intrusions in this belt remains unclear. This study presents zircon U–Pb dating and trace elements, apatite major and trace elements as well as published whole-rock geochemical and isotopic data of the Dongga tonalite in the central part of the Gangdese belt, aiming to reveal the petrogenesis, oxidation state, volatile content, and Cu mineralization potential of this intrusion. The Dongga tonalite has a zircon U–Pb age of 179.4 ± 0.9 Ma. It exhibits high whole-rock V/Sc values(8.76–14.6), relatively low apatite CeN/CeN*ratios(1.04–1.28), elevated zircon(Eu/Eu*)Nvalues(an average of 0.44), high Ce4+/Ce3+values(205–1896), and high ?FMQ values(1.3–3.7), collectively suggesting a high magmatic oxygen fugacity. The Dongga tonalite features amphibole phenocrysts, relatively high whole-rock Sr/Y ratios(20.3–58.9), and lower zircon Ti temperatures (502–740 ℃), reflecting a high magmatic water content. Estimation of magmatic sulfur content(0.002–0.024 wt%) based on apatite SO3contents indicates an enriched magma sulfur content. Combined with previous studies and the collected Sr–Nd–Hf isotopes, the Dongga tonalite is derived from juvenile lower crust related with subduction of the Neo-Tethys oceanic slab. When compared with Xietongmen orebearing porphyries, the Dongga tonalite exhibits remarkable similarities with the Xietongmen ore-bearing porphyries in terms of magma source, tectonic background, magmatic redox state, and volatile components, which indicates that the Dongga tonalite has a high porphyry Cu mineralization potential, and therefore, provides important guidance for the future mineralization exploration.
基金supported by the Natural Science Foundation of Shandong Province(Grant No.ZR2022QD055)the Taishan Scholars(Grant No.tstp 20231214)the National Natural Science Foundation of China(Grant No.42372247).
文摘Post-collisional magmatism contains important clues for understanding the reworking and growth of continental crust,as well as lithospheric delamination and orogenic collapse.Early Devonian magmatism has been identified in the North Qilian Orogenic Belt(NQOB).This paper reports an integrated study of petrology,whole-rock geochemistry,Sm-Nd isotope and zircon U-Pb dating,as well as Lu-Hf isotopic data,for two Early Devonian intrusive plutons.The Yongchang and Chijin granites yield zircon U-Pb ages of 394-407 Ma and 414 Ma,respectively.Both of them are characterized by weakly peraluminous to metaluminous without typical aluminium-rich minerals,LREE-enriched patterns with negative Eu anomalies and a negative correlation between P_(2)O_(5) and SiO_(2) contents,consistent with geochemical features of I-type granitoids.Zircons from the studied granites display negative to weak positive ε_(Hf)(t)values(−5.7 to 2.1),which agree well with those of negative ε_(Nd)(t)values(−6.4 to−2.9)for the whole-rock samples,indicating that they were derived from the partial melting of Mesoproterozoic crust.Furthermore,low Sr/Y ratios(1.13-21.28)and high zircon saturation temperatures(745℃ to 839℃,with the majority being>800℃)demonstrated a relatively shallow depth level below the garnet stability field and an additional heat source.Taken together,the Early Devonian granitic magmatism could have been produced by the partial melting of ancient crustal materials heated by mantle-derived magmas at high-temperature and low-pressure conditions during postcollisional extensional collapse.The data obtained in this study,when viewed in conjunction with previous studies,provides more information about the tectonic processes that followed the closure of the North Qilian Ocean.The tectonic transition from continental collision to post-collisional delamination could be constrained to~430 Ma,which is provided by the sudden decrease of Sr/Y and La/Yb ratios and an increase in zircon ε_(Hf)(t)values for granitoids.A two-stage tectonic evolution model from continental collision to post-collisional extensional collapse for the NQOB includes(a)continental collision and crustal thickening during ca.455-430 Ma,characterized by granulite-facies metamorphism and widespread low-Mg adakitic magmatism;(b)post-collisional delamination of thickened continental crust and extensional collapse of orogen during ca.430-390 Ma,provided by coeval high-Mg adakitic magmatism,A-type granites and I-type granitoids with low Sr-Y ratios.
基金funded by Gansu Provincial Natural Science Foundation (Grant Numbers 21JR7RA503 and22JR5RA819)the Fundamental Research Funds for the Central Universities (Grant lzujbky-2021-ct07)+1 种基金the Key Talent Project of Gansu Province (2022-Yangzhenxi)the National Second Expedition to the Tibetan Plateau (2019QZKK0704)。
文摘Geodynamic mechanism responsible for the generation of Silurian granitoids and the tectonic evolution of the Qilian orogenic belt remains controversial. In this study, we report the results of zircon U–Pb age, and systematic whole-rock geochemical data for the Haoquangou and Liujiaxia granitoids within the North Qilian orogenic belt and the Qilian Block, respectively, to constrain their petrogenesis, and the Silurian tectonic evolution of the Qilian orogenic belt. Zircon U–Pb ages indicate that the Haoquangou and Liujiaxia intrusions were emplaced at423 ± 3 Ma and 432 ± 4 Ma, respectively. The Haoquangou granodiorites are calc-alkaline, while the Liujiaxia granites belong to the high-K calc-alkaline series.Both are peraluminous in composition and have relatively depleted Nd isotopic [ε_(Nd)(t) =(-3.9 – + 0.6)] characteristics compared with regional basement rocks, implying their derivation from a juvenile lower crust. They show adakitic geochemical characteristics and were generated by partial melting of thickened lower continental crust. Postcollisional extensional regime related to lithospheric delamination was the most likely geodynamic mechanism for the generation of the Haoquangou granodiorite, while the Liujiaxia granites were generated in a compressive setting during continental collision between the Qaidam and Qilian blocks.
基金jointly supported by the China National Science Foundation under Grant Nos.41875172 and 42075192。
文摘This paper studied a snow event over North China on 21 February 2017,using aircraft in-situ data,a Lagrangian analysis tool,and WRF simulations with different microphysical schemes to investigate the supercooled layer of warm conveyor belts(WCBs).Based on the aircraft data,we found a fine vertical structure within clouds in the WCB and highlighted a 1-2 km thin supercooled liquid water layer with a maximum Liquid Water Content(LWC) exceeding0.5 g kg^(-1) during the vertical aircraft observation.Although the main features of thermodynamic profiles were essentially captured by both modeling schemes,the microphysical quantities exhibited large diversity with different microphysics schemes.The conventional Morrison two-moment scheme showed remarkable agreement with in-situ observations,both in terms of the thermodynamic structure and the supercooled liquid water layer.However,the microphysical structure of the WCB clouds,in terms of LWC and IWC,was not apparent in HUJI fast bin scheme.To reduce such uncertainty,future work may focus on improving the representation of microphysics in bin schemes with in-situ data and using similar assumptions for all schemes to isolate the impact of physics.
基金the National Natural Science Foundation of China(Grant Nos.42188101,42025404,41974186,42174188,and 42204160)the National Key R&D Program of China(Grant No.2022YFF0503700)+2 种基金the B-type Strategic Priority Program of the Chinese Academy of Sciences(Grant No.XDB41000000)the Fundamental Research Funds for the Central Universities(Grant Nos.2042022kf1016 and 2042023kf1025)the China Postdoctoral Science Foundation(Grant No.2022M722447)。
文摘The energy spectrum of energetic electrons is a key factor representing the dynamic variations of Earth’s Van Allen radiation belts.Increased measurements have indicated that the commonly used Maxwellian and Kappa distributions are inadequate for capturing the realistic spectral distributions of radiation belt electrons.Here we adopt the Kappa-type(KT)distribution as the fitting function and perform a statistical analysis to investigate the radiation belt electron flux spectra observed by the Van Allen Probes.By calculating the optimal values of the key KT distribution parameters(i.e.,κandθ2)from the observed spectral shapes,we fit the radiation belt electron fluxes at different L-shells under different geomagnetic conditions.In this manner,we obtain typical values of the KT distribution parameters,which are statistically feasible for modeling the radiation belt electron flux profiles during either geomagnetically quiet or active periods.A comparison of the KT distribution model results with those using the Maxwellian or Kappa distribution reveals the advantage of the KT distribution for studying the overall properties of the radiation belt electron spectral distribution,which has important implications for deepening the current understanding of the radiation belt electron dynamics under evolving geomagnetic conditions.
基金funded by the National Natural Science Foundation of China(41872232)the Beijing Geological Survey Project(PXM 2016-158203-000008,PXM 2018-158203-000014)the Beijing Innovation Studio(Urban Geology,Active Structure,and Monitoring).
文摘The Nianzi granite unit,which includes the Nianzi,Xiaolianghou and Xiawopu granitic intrusions,is a significant component of the northern part of the North China Craton(NCC)and is situated in the Yanshan fold and thrust belt(YFTB).However,there is still debate regarding the tectonic evolutionary history of the YFTB during the late Permian to Triassic period,specifically regarding the timing of subduction and collision between the NCC and the Paleo-Asian Ocean.The Nianzi granite unit exhibits unique petrological,geochronological and geochemical signatures that shed light on the tectonic evolutionary history of the YFTB.This study presents detailed petrology,whole-rock geochemistry,together with Sr-Nd isotopic,zircon U-Pb dating and Lu-Hf isotopic data of the granites within the Nianzi granite unit.Our findings demonstrate that the granites primarily consist of subhedral K-feldspar,plagioclase,quartz,minor biotite and hornblende,with accessory titanite,apatite,magnetite and zircon.Zircon U-Pb dating indicates that the Xiaolianghou granite was emplaced at 247.5±0.62 Ma.Additionally,the adakitic characteristics of the Nianzi,Xiawopu and Xiaolianghou granitic intrusions,such as high Sr and Ba contents and high ratios of Sr/Y and(La/Yb)N,combined with negative Sr-Nd and Lu-Hf isotopes(87Sr/86Sr)i=0.705681–0.7057433,εNd(t)=−21.98 to−20.97,zirconεHf(t)=−20.26 to−9.92,as well as the I-type granite features of high SiO_(2),Na_(2)O and K_(2)O/Na_(2)O ratios,enriched Rb,K,Sr and Ba,along with depleted Th,U,Nb,Ta,P and Ti,suggest that the Nianzi granitic unit was mainly derived from the partial melting of a thickened lower crust containing hydrous,calc-alkaline to high-K calc-alkaline,mafic to intermediate metamorphic rocks.In light of these parameters,we further integrate our data with previous studies and conclude that the Nianzi granitic unit was generated in a post-collisional extensional environment during the Early Triassic.
基金supported by the Hebei Province Cultural and Artistic Science Planning and Tourism Research Project[Grant No.HB22-ZD002].
文摘Carbon peak and carbon neutrality(dual-carbon)are important targets for the international response to climate change.The Silk Road Economic Belt is a strategic resource region and is important for future ecological environment and tourism development.Based on the“dual-carbon”targets,the Single index quantification,Multiple index synthesis,and Poly-criteria integration evaluation model were used in this study to measure the coordinated development index of the ecological environment,public service,and tourism economy along the Silk Road Economic Belt and to analyze its spatial and temporal evolution.Further,it explores the dynamic evolution and development trend of the three systems using the Kernel Density and Grey Markov Prediction Model.The results show that the coordinated development index along this region needs to be improved during the study period.Furthermore,the coordinated development index of the Southwest region is relatively higher than that of the Northwest region.From the development trend of the three systems,all of them develop in a stable manner;however,the tourism economy system is easily affected by external disturbances.The coordinated development index of the three systems changes dynamically and tends to be in a good state of coordination.There is a certain spatial and temporal heterogeneity.The gravity center of the coordinated development index has been in the Southwest region.During the forecast period,the coordinated development index along this region will improve significantly,while insufficient and unbalanced development will continue.
基金Supported by National Natural Science Foundation of China,No.82260532,and No.32060208.
文摘BACKGROUND Colorectal cancer(CRC)plays a significant role in morbidity,mortality,and economic cost in the Belt and Road Initiative(“B and R”)countries.In addition,these countries have a substantial consumption of processed meat.However,the burden and trend of CRC in relation to the consumption of a diet high in processed meat(DHPM-CRC)in these“B and R”countries remain unknown.AIM To analyze the burden and trend of DHPM-CRC in the“B and R”countries from 1990 to 2019.METHODS We used the 2019 Global Burden of Disease Study to collate information regarding the burden of DHPM-CRC.Numbers and age-standardized rates(ASRs)of deaths along with the disability-adjusted life years(DALYs)were determined among the“B and R”countries in 1990 and 2019.Using joinpoint regression analysis,the average annual percent change(AAPC)was used to analyze the temporal trends of age-standardized DALYs rate(ASDALR)from 1990 to 2019 and in the final decade(2010–2019).RESULTS We found geographical differences in the burden of DHPM-CRC among“B and R”countries,with the three highest-ranking countries being the Russian Federation,China,and Ukraine in 1990,and China,the Russian Federation,and Poland in 2019.The burden of DHPM-CRC generally increased in most member countries from 1990 to 2019(all P<0.05).The absolute number of deaths and DALYs in DHPM-CRC were 3151.15[95%uncertainty interval(UI)665.74-5696.64]and 83249.31(95%UI 15628.64-151956.31)in China in 2019.However,the number of deaths(2627.57-2528.51)and DALYs(65867.39-55378.65)for DHPM-CRC in the Russian Federation has declined.The fastest increase in ASDALR for DHPM-CRC was observed in Vietnam,Southeast Asia,with an AAPC value of 3.90%[95%confidence interval(CI):3.63%-4.16%],whereas the fastest decline was observed in Kyrgyzstan,Central Asia,with an AAPC value of-2.05%(95%CI:-2.37%to-1.73%).A substantial upward trend in ASR of mortality,years lived with disability,years of life lost,and DALYs from DHPM-CRC changes in 1990-2019 and the final decade(2010-2019)for most Maritime Silk Route members in East Asia,South Asia,Southeast Asia,North Africa,and the Middle East,as well as Central Europe,while those of the most Land Silk Route members in Central Asia and Eastern Europe have decreased markedly(all P<0.05).The ASDALR for DHPM-CRC increased more in males than in females(all P<0.05).For those aged 50-74 years,the ASDALR for DHPM-CRC in 40 members exhibited an increasing trend,except for 20 members,including 7 members in Central Asia,Maldives,and 12 high or high-middle social development index(SDI)members in other regions(all P<0.05).CONCLUSION The burden of DHPM-CRC varies substantially across“B and R”countries and threatens public health.Relevant evidence-based policies and interventions tailored to the different trends of countries in SDIs or Silk Routes should be adopted to reduce the future burden of CRC in“B and R”countries via extensive collaboration.
基金National Natural Science Foundation of China(41930972,52239006,41975001)。
文摘A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics of the frontal and warm sector rain belts that occurred in South China on May 10–13,2022.The southern rain belt occurred in an environment with favorable mesoscale conditions but weak large-scale forcing.In contrast,the northern rain belt was related to low-level horizontal shear and the surface-level front.The interaction between the enhanced southeasterly winds and the rainfall-induced cold pool promoted the persistent growth of convection along the southern rain belt.The convective cell propagated east over the coastal area,where there was a large temperature gradient.The bow-shaped echo in this region may be closely related to the rear-inflow jet.By contrast,the initial convection of the northern rain belt was triggered along the front and the region of low-level horizontal shear,with mesoscale interactions between the enhanced warm-moist southeasterly airflow and the cold dome associated with the earlier rain.The terrain blocked the movement of the cold pool,resulting in the stagnation of the frontal convective cell at an early stage.Subsequently,a meso-γ-scale vortex formed during the rapid movement of the convective cell,corresponding to an enhancement of precipitation.The representative raindrop spectra for the southern rain belt were characterized by a greater number and higher density of raindrops than the northern rain belt,even though both resulted in comparable hourly rainfalls.These results help us better understand the characteristics of double rain belts over South China.
基金Supported by Special Soft Science Research Project for Hubei Province Science and Technology Innovation Talents and Services(2022EDA060).
文摘Accelerating the construction of agricultural power,further promoting the high-quality development of the Yangtze River Economic Belt,and better supporting and serving Chinese-style modernization are the key issues at present.This paper first introduces the Yangtze River Economic Belt and its ethnic areas,and studies the characteristics of the grain and oil industry in the ethnic autonomous areas of the economic belt,as well as the current situation of various types of intellectual property resources,such as industrial cultural heritage,scientific and tech-nological innovation,and brand marking intellectual property.Besides,it analyzes the main problems in the high-quality development of grain and oil in the Yangtze River Economic Belt ethnic areas.Finally,it comes up with recommendations,including protecting the intellectual prop-erty rights of cultural heritage in the field of grain and oil,leading the inheritance and development of excellent traditional Chinese culture,use scientific and technological innovation intellectual property rights to promote the innovation-driven development strategy of the grain and oil in-dustry,and providing counterpart assistance to ethnic autonomous areas in the Yangtze River Economic Belt to further promote the high-quality development of the Yangtze River Economic Belt.
基金supported by Teaching and Research Project of North China Institute of Aerospace Engineering(JY-2023-19)Humanities and Social Science Research Project of Hebei Education Department(SQ2024272).
文摘This study employs Norman Fairclough’s Critical Discourse Analysis(CDA)three-dimensional model,using the Republic of Kazakhstan as a case study,to delve into the discourse construction of China’s Belt and Road Initiative(BRI)in Central Asian countries.Through detailed analysis of policy documents,media reports,and public discussions in Central Asian countries,this paper reveals how the BRI constructs specific social practices,discourse events,and textual meanings within these nations.The findings indicate that through this global development strategy,China has not only strengthened its economic ties with Central Asian countries but has also exerted profound influences on political,cultural,and social levels.
基金Supported by the National Natural Science Foundation of China (41902118)Natural Science Foundation of Xinjiang Uygur Autonomous Region (2022D01B141)+1 种基金Natural Science Foundation of Heilongjiang Province (LH2021D003)Heilongjiang Postdoctoral Fund (No.LBH-Z20045)。
文摘Using the data of drilling, logging, core, experiments and production, the heterogeneity and differential hydrocarbon accumulation model of deep reservoirs in Cretaceous Qingshuihe Formation(K1q) in the western section of the foreland thrust belt in southern Junggar Basin are investigated. The target reservoirs are characterized by superimposition of conglomerates, sandy conglomerates and sandstones, with high content of plastic clasts. The reservoir space is mainly composed of intergranular pores. The reservoirs are overall tight, and the sandy conglomerate has the best physical properties. The coupling of short deep burial period with low paleotemperature gradient and formation overpressure led to the relatively weak diagenetic strength of the reservoirs. Specifically, the sandy conglomerates show relatively low carbonate cementation, low compaction rate and high dissolution porosity. The special stress-strain mechanism of the anticline makes the reservoirs at the top of the anticline turning point more reformed by fractures than those at the limbs, and the formation overpressure makes the fractures in open state. Moreover, the sandy conglomerates have the highest oil saturation. Typical anticline reservoirs are developed in deep part of the thrust belt, but characterized by "big trap with small reservoir". Significantly, the sandy conglomerates at the top of anticline turning point have better quality, lower in-situ stress and higher structural position than those at the limbs,with the internal hydrocarbons most enriched, making them high-yield oil/gas layers. The exponential decline of fractures makes hydrocarbon accumulation difficult in the reservoirs at the limbs. Nonetheless, plane hydrocarbon distribution is more extensive at the gentle limb than the steep limb.
基金substantially supported by the National Nature Science Foundation of China(Grant No.41872220)。
文摘The North Qinling Orogenic Belt(NQOB)is a composite orogenic belt in central China.It started evolving during the Meso-Neoproterozoic period and underwent multiple stages of plate subduction and collision before entering intra-continental orogeny in the Late Triassic.The Meso-Cenozoic intra-continental orogeny and tectonic evolution had different responses in various terranes of the belt,with the tectonic evolution of the middle part of the belt being particularly controversial.The granites distributed in the Dayu and Kuyu areas in the middle part of the NQOB can provide an important window for revealing the geodynamic mechanisms of the NQOB.The main lithology of Dayu and Kuyu granites is biotite monzogranite,and the zircon U-Pb dating yielded intrusive ages of 151.3±3.4 Ma and 147.7±1.5 Ma,respectively.The dates suggest that the biotite monzogranite were formed at the end of the Late Jurassic.The whole-rock geochemistry analysis shows that the granites in the study areas are characterized by slightly high SiO_(2)(64.50-68.88 wt%)and high Al_(2)O_(3)(15.12-16.24 wt%)and Na_(2)O(3.55-3.80 wt%)contents.They are also enriched in light rare earth elements,large ion lithophile elements(e.g.,Ba,K,La,Pb and Sr),and depleted in high field strength elements(HFSEs)(e.g.,Ta,Nb,P and Ti).Additionally,the granites have weakly negative-slightly positive Eu anomalies(δEu=0.91-1.19).Zircon Lu-Hf isotopic analysis showedε_(Hf)(t)=-6.1--3.8,and the two-stage model age is T_(2DM(crust))=1.5-1.6 Ga.The granites in the study areas are analyzed as weak peraluminous high-K calc-alkaline I-type granites.They formed by partial melting of the thickened ancient lower crust,accompanied by the addition of minor mantle-derived materials.During magma ascent,they experienced fractional crystallization,with residual garnet and amphibole for a certain proportion in the magma source region.Comprehensive the geotectonic data suggest that the end of the Late Jurassic granite magmatism in the Dayu and Kuyu areas represents a compression-extension transition regime.It may have been a response to multiple tectonic mechanisms,such as the late Mesozoic intra-continental southward subduction of the North China Craton and the remote effect of the Paleo-Pacific Plate subduction.
基金Supported by Fundamental Research Funds for the Central Universities of China (Grant No.2019JBM050)。
文摘The current research of abrasive belt grinding rail mainly focuses on the contact mechanism and structural design.Compared with the closed structure abrasive belt grinding,open-structured abrasive belt grinding has excellent performance in dynamic stability,consistency of grinding quality,extension of grinding mileage and improvement of working efficiency.However,in the contact structure design,the open-structured abrasive belt grinding rail using a profiling pressure grinding plate and the closed structure abrasive belt using the contact wheel are different,and the contact mechanisms of the two are different.In this paper,based on the conformal contact and Hertz theory,the contact mechanism of the pressure grinding plate,abrasive belt and rail is analyzed.Through finite element simulation and static pressure experiment,the contact behavior of pressure grinding plate,abrasive belt and rail under single concentrated force,uniform force and multiple concentrated force was studied,and the distribution characteristics of contact stress on rail surface were observed.The results show that under the same external load,there are three contact areas under the three loading modes.The outer contour of the middle contact area is rectangular,and the inner contour is elliptical.In the contact area at both ends,the stress is extremely small under a single concentrated force,the internal stress is drop-shaped under a uniform force,and the internal stress under multiple concentration forces is elliptical.Compared with the three,the maximum stress is the smallest and the stress distribution is more uniform under multiple concentrated forces.Therefore,the multiple concentrated forces is the best grinding pressure loading mode.The research provides support for the application of rail grinding with open-structured abrasive belt based on pressure grinding plate,such as contact mechanism and grinding pressure mode selection.
基金supported by funds from the National Natural Science Foundation of China(Grant Nos.42172067,41972064,U1906207)the SDUST Research Fund。
文摘Gneisses with anatectic characteristics from the Liansan island in the Sulu UHPM(ultra-high pressure metamorphic)belt were studied for petrography,titanite U-Pb dating and mineral geochemistry.Three origins of garnets are distinguished:metamorphic garnet,peritectic garnet and anatectic garnet,which are formed in the stages of peak metamorphism,retrograde anatexis and melt crystallization,respectively.The euhedral titanite has a high content of REE and high Th/U ratios,which is interpreted as indicating that it was newly-formed from an anatectic melt.The LA-ICP-MS titanite U-Pb dating yields 214-217 Ma ages for the titanite(melt)crystallization.The distribution of trace elements varies in response to the different host minerals at different stages.At the peak metamorphic stage,Y and HREE are mainly hosted by garnet,Ba and Rb by phengite,Sr,Nb,Ta,Pb,Th,U and LREE by allanite and Y,U and HREE by zircon.During partial melting,Y,Pb,Th,U and REE are released into the melt,which causes a dramatic decline of these element contents in the retrograde minerals.Finally,titanite absorbs most of the Nb,U,LREE and HREE from the melt.Therefore,the different stages of metamorphism have different mineral assemblages,which host different trace elements.
基金The Ministry of Land and Resources Project of Oil and Gas Resource Investigation and Evaluation under contract Nos XQ-2004-05 and XQ-2007-05the National Key Basic Research Program of China(973 Program)under contract No.2009CB219400+3 种基金the National Science and Technology Major Project under contract Nos 2008ZX05025,2011ZX05025 and2016ZX05026the National Natural Science Foundation under contract Nos 41872172 and 42072188the Research and Innovation Team Support Program of Shandong University of Science and Technology under contract No.2018TDJH101Hebei Provincial Resources Survey and Research Laboratory Open Foundation。
文摘Sea area is an important area of oil and gas exploration in China.It has been found that China's sea area mainly consists of coal type oil and gas,and the exploration of coal-bearing series source rocks has become an important part of oil and gas exploration there.Through years of comprehensive geological research in China's sea area,it has been revealed that it has undergone multiple occurrences of tectonic opening and closing movements in varying degrees in the Paleogene,forming 26 Cenozoic sedimentary basins of various types,such as active continental margin,passive continental margin,transitional continental margin and drift rift basins.In the present study,it is observed for the first time that coal type source rocks are mainly developed in 14 continental margin basins in China's sea area,revealing that a very large C-shaped coal-bearing basin group developed there in the Cenozoic.Next,based on the coupling analysis of paleoclimate,paleobotany,paleogeography and paleostructure,it is observed that there are five coal-forming periods in China's sea area,namely the Paleocene,Eocene,early Oligocene,late Oligocene and Miocene-Pliocene,and the coal-forming age is gradually new from north to south.It is also found that the coal seams in the sea area are mainly developed in three coal-forming environments in Cenozoic,namely delta,fan delta and tidal flat-lagoon.The coal seams developed in different environments are characterized by thin thickness,many layers and poor stability.However,the coal-bearing series source rocks in China's sea area have a wide distribution range,very high thickness and large amount,thus forming a material basis for the formation of rich coal type oil and gas.
基金Supported by the Sinopec Science and Technology Project(P21040-1).
文摘In the second member of the Upper Triassic Xujiahe Formation(T_(3)x_(2))in the Xinchang area,western Sichuan Basin,only a low percent of reserves has been recovered,and the geological model of gas reservoir sweet spot remains unclear.Based on a large number of core,field outcrop,test and logging-seismic data,the T_(3)x_(2) gas reservoir in the Xinchang area is examined.The concept of fault-fold-fracture body(FFFB)is proposed,and its types are recognized.The main factors controlling fracture development are identified,and the geological models of FFFB are established.FFFB refers to faults,folds and associated fractures reservoirs.According to the characteristics and genesis,FFFBs can be divided into three types:fault-fracture body,fold-fracture body,and fault-fold body.In the hanging wall of the fault,the closer to the fault,the more developed the effective fractures;the greater the fold amplitude and the closer to the fold hinge plane,the more developed the effective fractures.Two types of geological models of FFFB are established:fault-fold fracture,and matrix storage and permeability.The former can be divided into two subtypes:network fracture,and single structural fracture,and the later can be divided into three subtypes:bedding fracture,low permeability pore,and extremely low permeability pore.The process for evaluating favorable FFFB zones was formed to define favorable development targets and support the well deployment for purpose of high production.The study results provide a reference for the exploration and development of deep tight sandstone oil and gas reservoirs in China.
基金granted by the National Natural Science Foundation of China(Grant Nos.41872194,41872203)the Regional Geological Survey Project of Huai′an,Hebei-Liangcheng,Inner Mongolia(Grant No.DD20190035)。
文摘We investigated the meta-gabbronorites in Liangcheng and used detailed petrography,geochemistry,zircon geochronological and in-situ Hf isotopic studies to clarify their formation and metamorphic ages,petrogenesis,tectonic setting and provide constraints on the tectonic evolution of Khondalite Belt(KB).The zircon U-Pb dating results show that the meta-gabbronorites crystallized at~1.94 Ga and were metamorphosed at~1.91–1.89 Ga.They can be subdivided into the low-Mg and high-Mg groups.The low-Mg meta-gabbronorites contain relatively lower MgO and higher SiO2 contents than high-Mg meta-gabbronorites.They are enriched in light rare earth elements and large ion lithophile elements,depleted in high field strength elements,and exhibit positive(high-Mg meta-gabbronorites)and negative(low-Mg metagabbronorites)Sr and Eu anomalies.The zircon in-situεHf(t)of meta-gabbronorites is 0.07–4.12,with Hf model ages(TDM)of 2169–2400 Ma.The meta-gabbronorites in Liangcheng originated from the asthenospheric mantle and experienced fractional crystallization of olivine,orthopyroxene,clinopyroxene,and plagioclase.They were contaminated by the crustal rocks(mainly khondalite series)during ascent,especially for low-Mg gabbronorites.The ridge subduction is the most plausible tectonic setting for meta-gabbronorites,indicating the eastern segment of KB was in a ridge subduction setting at~1.94 Ga following an orogenic thickening event during a prolonged orogenic process.
文摘The dimensions and connectivity of fluvial reservoirs vary greatly, making it challenging to characterize them using conventional approaches. In this study integrated channel belt dimension analysis from seismic geomorphology and empirical equations, well log facies, and petrophysical analysis were performed to characterize the fluvial reservoirs. The study interval consists of fluvial deposits and is divided into three reservoir zones, which are defined by four key regional markers (B, D, K, O). In these intervals, six (6) fluvial facies have been identified. Based on the log facies proportions and their stacking relationships, it is interpreted that the reservoirs in zone 1 (B to D) were deposited in a proximal reach of a meandering system, zone 2 (D to K) in a marginal marine setting, and zone 3 (K) in a distal reach of a meandering system. The dimensions of fluvial channels and channel belts were determined using empirical equations. The results were compared with the observed dimensions of fluvial channels and channel belts from the seismic horizon and stratal slices of the same intervals. Zones 1 and 3 are characterized by broad meander belts (1000–4000 m) compared to zone 2 (600–1300 m). Petrophysical analysis showed zones 1 and 3 have the better petrophysical properties compared to zone 2. Though zone 3 has the most well-developed sand bodies, the best reservoir interval is zone 1 because of its higher porosity. Although channel belt dimensions have a significant influence on reservoir connectivity, they do not seem to have control on reservoir properties. The channel belt dimensions obtained from the empirical equations and interpreted from the seismic geomorphology analysis were found to be strikingly similar. Since three-dimensional seismic data is not available everywhere and seismic imaging quality decreases with depth, empirical equations can be used to analyze fluvial reservoir parameters and their connectivity at greater depths.
