Gas-bearing shales have become a major source of future natural gas production worldwide.It has become increasingly urgent to develop a reliable prediction model and corresponding workflow for identifying shale gas sw...Gas-bearing shales have become a major source of future natural gas production worldwide.It has become increasingly urgent to develop a reliable prediction model and corresponding workflow for identifying shale gas sweet spots.The formation of gas-bearing shales is closely linked to relative sealevel changes,providing an important approach to predicting sweet spots in the Wufeng-Longmaxi shale in the southern Sichuan Basin,China.Three types of marine shale gas sweet spots are identified in the shale based on their formation stages combined with relative sea-level changes:early,middle,and late transgression types.This study develops a prediction model and workflow for identifying shale gas sweet spots by analyzing relative sea-level changes and facies sequences.Predicting shale gas sweet spots in an explored block using this model and workflow can provide a valuable guide for well design and hydraulic fracturing,significantly enhancing the efficiency of shale gas exploration and development.Notably,the new prediction model and workflow can be utilized for the rapid evaluation of the potential for shale gas development in new shale gas blocks or those with low exploratory maturity.展开更多
Abstract Experimental examinations and analyses have been made of the sediments from drill holes in the Zhuhai area, Guangdong Province. The studies show that there occurred four transgressions in this area over the h...Abstract Experimental examinations and analyses have been made of the sediments from drill holes in the Zhuhai area, Guangdong Province. The studies show that there occurred four transgressions in this area over the historical times. The first transgression occurred at 7500 a B.P., with the maxium sea level up to about 1 m above the present level. The second transgression occurred at 5750 a B.P., with the sea level possibly 4 m higher than the present. The third and fourth transgressions took place at 4650 a B.P. and 2600 a B.P. respectively, which lasted for a long time with multiple fluctuations. The fifth transgression is in process. It could be predicted that the sea level at Zhuhai would rise by 15–20 cm in the coming 50 years.展开更多
Several views on sea-level changes of the South China coast are briefly introduced in this paper. On the basis of 236 samples whose ages are determined by 14C chronological method and their sites are corrected with an...Several views on sea-level changes of the South China coast are briefly introduced in this paper. On the basis of 236 samples whose ages are determined by 14C chronological method and their sites are corrected with ancient water depth and crustal deformation, a basic model about sea-level changes of the South China coast since late Epipleistocene is set up. This model basically accords with the general cognitions of predecessors, i. e. it not only represents the common characteristics of sea-level changes of the East China coast but has some features of the South China coast itself. In general, this model is relatively close to the Fairbridge's curve, indicating that the sea-level undulations exist since 6 ka ago but the ranges of undulations are slightly larger than those of Fairbridge's curve.展开更多
Cambrian System at the Shatan Section in northern Henan,North China,consists of sedimentary successions of tidal flat and shallow-water carbonate platform facies.Data of carbon isotope(δ^(13)C_(carb))from this sectio...Cambrian System at the Shatan Section in northern Henan,North China,consists of sedimentary successions of tidal flat and shallow-water carbonate platform facies.Data of carbon isotope(δ^(13)C_(carb))from this section reveals five positive δ^(13)C_(carb)(P_(st-1)-P_(st-5))and five negative δ^(13)C_(carb) excursions(N_(st-1)-N_(st-5)).In the positive excursions,δ^(13)C_(carb) rises to 0.88‰,1.05‰,2.04‰,1.00‰ and 2.97‰,respectively,while in the negative excursions δ^(13)C_(carb) drops to -8.00‰,-3.50‰,-1.00‰,-0.33‰ and around -2.00‰,respectively.On the basis of chronostratigraphy of Cambrian,the most remarkable carbon isotope excursions can be correlated regionally and globally.In addition,one second-order and ten third-order sequences have been recognized at this section.Correlating third-order sequences and chemostratigraphy indicates that carbonates from the basal part of the transgression system tract(TST)and the upper part of the high-water system(LHST)generally have lighter δ^(13)C_(carb) values,whereas massive carbonates with microbialite from the lower part of the high-water system tract(EHST)usually have heavier δ^(13)C_(carb) values.The association of δ^(13)C_(carb) values with sea-level fluctuations suggests that the positive carbon isotope excursions or high δ^(13)C_(carb) values may have been caused by an increase in the marine primary productivity in response to maximum seawater flooding during the transgression.展开更多
The platform-facies carbonate rocks of the Carboniferous-Permian boundary strata are well developed and outcropped in Xikou （西口）, Zhen＇an （镇安） County, Shaanxi （ 陕西 ） Province, China. The carbonate diagenc...The platform-facies carbonate rocks of the Carboniferous-Permian boundary strata are well developed and outcropped in Xikou （西口）, Zhen＇an （镇安） County, Shaanxi （ 陕西 ） Province, China. The carbonate diagencsis in the Carboniferous-Permian boundary section at Xikou contains many processes with conspicuous effects, including micritization, cementation, mechanical and chemical compaction, neomorphism, and dissolution. Based on mineralogical composition and microfabrics, the diagenetic environments are distinguished into marine, near surface meteoric and burial environments. Detailed petrographical observation of abundant thin sections integrated with previous studies on sequence stratigraphy reveals that the carbonate diagenesis in the Carboniferous-Permian boundary section is related to the relative stratigraphic position of the rocks in the high-frequency cycles and controlled by the glacioeustatic sea-level changes. There are distinctive differences in diagenetic patterns between the lower transgressive sequence and the upper regressive sequence in a cyclothem. The diagenesis in the lower transgressive sequence is mainly characterized by pressure dissolution and recrystallization of mudstone and wackstone in a burial environment, and the diagenesis in the upper regressive sequence by cementation and leaching of freshwater in a meteoric environment.展开更多
The sedimentary sequences since the Late Pleistocene can be divided into Layers E, D, C, B, A from old to young according to systematic analysis of grain-size, pollen and spore, diatom, foraminifera, radiocarbon datin...The sedimentary sequences since the Late Pleistocene can be divided into Layers E, D, C, B, A from old to young according to systematic analysis of grain-size, pollen and spore, diatom, foraminifera, radiocarbon dating and paleogeomagnetism of 16 sedimentary cores from the sea area of the western Taiwan Strait. The results proved the existences of the Langqi transgression (upper section of Layer D) formed in middle and late stages of early Wurm glacial period, Fuzhou transgression (Layer C) formed in Wurm sub-interglacial period and Changle transgression (Layer A) formed in postglacial period. It was also the first time to discover the Jinmen transgression (Layer E) formed in Riss -Wurm interglacial period. In this paper it is proposed that most part of the Taiwan Strait emerged as land in the early stage of early Wurm glacial period, and was still under sublittoral environment in late Wurm glacial period, as well as the existence of Dongshan Continental Bridge was in 8×103 a BP.展开更多
Detrital sediments derived from the Philippine Islands are one of the main sources of deep-sea sediments in the western Philippine Sea.However,systematic research on their characteristics and transport mechanisms are ...Detrital sediments derived from the Philippine Islands are one of the main sources of deep-sea sediments in the western Philippine Sea.However,systematic research on their characteristics and transport mechanisms are lacking.We used parametric end-member analysis to quantitatively partition the grain size of detrital sediments in core MD06-3052 from the Bicol Shelf in the western Philippine Sea;three endmembers EMI,EM2,and EM3,whose respective modes were at 2,10,and 45 μm,were separated.We also measured the Sr and Nd isotopic compositions of different size fractions(<4 and >20 μm) of the detrital sediments and the results showed that the detrital sediments mainly originate from the Philippine Islands.Components EMI and EM2 are transported to the Bicol Shelf mainly by surface and bottom currents from the islands,and component EM3 is delivered by gravity flow from the exposed shelf during low sea-level stands.The content of the total detrital fraction and the three end-members,as well as the mass accumulation rates(MARs) of the coarse detritus(EM2 and EM3),were considerably higher during glacial periods(40-14 ka and 150-130 ka) than during other intervals;the glacials corresponded to a low sea level,while the MAR of the fine detritus(EMI) did not increase remarkably during 40-14 ka.We therefore concluded that the input of coarse detritus to the Bicol Shelf from the islands was mainly controlled by sea-level change.Variations of the input of fine-grained detritus(EM1) was influenced not only by sea level but also by ocean currents and regional precipitation.Overall,our results help understand "source-to-sink" processes in the western Pacific marginal seas and their response to global change.展开更多
Anthropogenic global warming and resulting sea-level rise in response to enhanced atmospheric greenhouse gases and melting of the Earth’s continental ice shields have become issues of continuously growing interest fo...Anthropogenic global warming and resulting sea-level rise in response to enhanced atmospheric greenhouse gases and melting of the Earth’s continental ice shields have become issues of continuously growing interest for the scientific community as well as the public,pointing to threads of societies in a future greenhouse Earth System.展开更多
-On the basis of the data obtained from the investigations on some rivers in China and Australia, the author discusses the spatial and temporal changes of various portions of fluvial-estuarine system during postglacia...-On the basis of the data obtained from the investigations on some rivers in China and Australia, the author discusses the spatial and temporal changes of various portions of fluvial-estuarine system during postglacial sea-level rising in present coastal and deltaic areas. The evolution of a fluvial-estuarine system can be divided into four development stages: early transgression, late transgression, stationary and regression. Early transgression brought about filling-in of the paleo-valley formed in low stand of sea level. In response to late transgression the estuaries were created, during the stationary stage the big swamp was developed. The regression led to estuaries to be filled with sediments and then became deltas. At the same locality the fluvial-estuarine system changed with time. In the transgressive period the lower reach of a river changed into an estuary, and then became nearshore area. In the regressive period the nearshore area changed into an estuary , and then became delta.展开更多
In this study,we estimate the absolute vertical land motions at three tidal stations with collocated Global Navigation Satellite System(GNSS)receivers over French Polynesia during the period 2007-2020,and obtain,as an...In this study,we estimate the absolute vertical land motions at three tidal stations with collocated Global Navigation Satellite System(GNSS)receivers over French Polynesia during the period 2007-2020,and obtain,as ancillary results,estimates of the absolute changes in sea level at the same locations.To verify our processing approach to determining vertical motion,we first modeled vertical motion at the International GNSS Service(IGS)THTI station located in the capital island of Tahiti and compared our estimate with previous independent determinations,with a good agreement.We obtained the following estimates for the vertical land motions at the tide gauges:Tubuai island,Austral Archipelago-0.92±0.17 mm/yr,Vairao village,Tahiti Iti:-0.49±0.39 mm/yr,Rikitea,Gambier Archipelago-0.43±0.17 mm/yr.The absolute variations of the sea level are:Tubuai island,Austral Archipelago 5.25±0.60 mm/yr,Vairao village,Tahiti Iti:3.62±0.52 mm/yr,Rikitea,Gambier Archipelago 1.52±0.23 mm/yr.We discuss these absolute values in light of the values obtained from altimetric measurements and other means in French Polynesia.展开更多
Tajikistan contains the majority of Central Asia’s glaciers,which cover about 6.00%of the national territory;their rapid shrinkage poses a significant threat to regional water resource security.However,glacier monito...Tajikistan contains the majority of Central Asia’s glaciers,which cover about 6.00%of the national territory;their rapid shrinkage poses a significant threat to regional water resource security.However,glacier monitoring in Tajikistan was interrupted after 1991,creating a substantial gap in understanding the current state and temporal evolution of these glaciers.Based on glacier inventory data,in situ measurements,and published literature,this study examined the present status and recent variations of glaciers in Tajikistan through data integration and validation,literature collation and comparative analysis,and the application of Geographic Information System(GIS)spatial analysis techniques.As of 2023,Tajikistan possesses a total of 11,528 glaciers,encompassing an area of 7624.48(±305.58)km2.Small glaciers dominate in number,whereas large glaciers account for the majority of the total area.Over the past two decades,the glacier count has decreased by 2014,and the total area has decreased by 628.98 km2,corresponding to an average annual reduction rate of 0.33%.Regional shrinkage rates range from 4.10%to 22.28%.Glaciers have undergone accelerated mass loss during the past 20 a;only those on the northeastern Pamir Plateau exhibit a weak positive mass balance.Observations of typical monitored glaciers also reveal intensified melting and retreat,consistent with regional trends.In light of the recent acceleration of glacier shrinkage in Tajikistan,focused measures should be implemented to strengthen glacier monitoring,enhance public awareness of glacier preservation,and promote the sustainable development and utilization of glacier tourism.These findings bridge the knowledge gap regarding the spatiotemporal dynamics of Tajikistan’s glaciers over recent decades and provide essential data support for regional water resource management.展开更多
Starting from the foundational static traits underlying the growth and development of flue-cured tobacco, this research conducts a systematic examination of the phenomena and theoretical principles associated with env...Starting from the foundational static traits underlying the growth and development of flue-cured tobacco, this research conducts a systematic examination of the phenomena and theoretical principles associated with environment-driven adaptive changes during its cultivation. It was found that environmental variables-including temperature, light, and moisture-elicit directional shifts in static traits ( e.g. , chemical composition, morphological architecture, and leaf tissue structure) toward enhanced environmental adaptation, characterized by graduality, juvenility, similarity, and correlativity. Upon alterations in ambient conditions, flue-cured tobacco modulates its static traits through integrated physical, chemical, and biological-genetic mechanisms, aiming to optimize resource utilization, mitigate environmental constraints, and preserve internal homeostasis alongside metabolic balance. The investigation further reveals that the adaptive scope of flue-cured tobacco to field environments is malleable and can be extended and elevated via adaptive conditioning commencing at the juvenile stage. In addition, the adaptive alignment between static traits and environmental parameters exerts a substantial impact on the plant s growth dynamics, yield performance, and quality attributes. Beyond its relevance to flue-cured tobacco, the proposed theory offers a meaningful framework for elucidating the pervasive adaptive strategies employed by plants and broader biological systems in response to environmental contingencies.展开更多
Knee osteoarthritis(KOA)is a chronic degenerative disease.Monosodium iodoac-etate(MIA)induction is the most commonly used therapeutic effect evaluation and mechanism of action research model;we observed a lack of stan...Knee osteoarthritis(KOA)is a chronic degenerative disease.Monosodium iodoac-etate(MIA)induction is the most commonly used therapeutic effect evaluation and mechanism of action research model;we observed a lack of standardization and uni-formity in current model building methods,which led us to conduct this study.Background:The aim was to investigate the time-and dose-related changes in the behavioral and pathological characteristics in the MIA-induced KOA model rat.Methods:MIA(40,50,and 60 mg/mL)was injected into the left joint of male Sprague-Dawley rats.After 2 weeks,the changes in the KOA rat model were observed by be-havioral evaluation,imaging-level evaluation,and histological-level evaluation.The changes were also compared after 40-mg/mL MIA injection for 2 and 6 weeks.Results:MIA-induced bone surface defects,osteophyte hyperplasia around the artic-ular rim,increased subchondral bone density,thinning of the sparse trabecular bone,structural disorder,and local clustering were observed.The degree of injury gradually increased with the increase in MIA concentration.After 6 weeks,subchondral bone density and sparse trabecular bone increased in the KOA model.Conclusions:The severity of the model also increased significantly with the changes in dose and time.In dose-dependent experiments,this study revealed that 40 mg/mL was the optimal dose to induce significant pathological changes without causing undue discomfort or death in animals.This dose may induce pathological changes stably and is suitable for long-term observation.展开更多
Lin Wei is a hiking enthusiast.At six o'clock on the last Saturday morning,the temperature at the foot of the mountain was only 2℃,so she put on her thickest fleece jacket.However,after only half an hour of climb...Lin Wei is a hiking enthusiast.At six o'clock on the last Saturday morning,the temperature at the foot of the mountain was only 2℃,so she put on her thickest fleece jacket.However,after only half an hour of climbing,the heat left her drenched in sweat,making her feel very cold.By midday,the temperature was approaching 20℃,and her heavy jacket had to be tied around her waist,becoming a burden during her hike.This outdoor adventure allowed her to appreciate the beautiful scenery,but also subjected her to repeated changes in temperature.展开更多
In recent years,against the backdrop of profound geopolitical changes,the European Union(EU)has been deeply mired in an industrial predicament,showing signs of shrinking production,capital outflows,relocation of produ...In recent years,against the backdrop of profound geopolitical changes,the European Union(EU)has been deeply mired in an industrial predicament,showing signs of shrinking production,capital outflows,relocation of production capacity,and lagging development in future industries.The primary causes of this situation include the energy supply crisis stemming from the decoupling from Russian energy,the impact of America's unilateral trade policy,structural flaws within the EU itself,and the intensification of global industrial competition.To overcome these challenges,the EU has introduced a series of new industrial policies,aiming at revitalizing its industries by strengthening support for local manufacturing,enhancing protective mechanisms for its domestic production,building diversified supply chains,and prioritizing the development of military industry.However,due to multiple obstacles such as heavy external dependence,significant funding gaps,internal divisions,and strategic short-sightedness,the EU still faces a long and arduous journey in its industrial revival.展开更多
BACKGROUND Lumbar interbody fusion(LIF)is the primary treatment for lumbar degenerative diseases.Elderly patients are prone to anxiety and depression after undergoing surgery,which affects their postoperative recovery...BACKGROUND Lumbar interbody fusion(LIF)is the primary treatment for lumbar degenerative diseases.Elderly patients are prone to anxiety and depression after undergoing surgery,which affects their postoperative recovery speed and quality of life.Effective prevention of anxiety and depression in elderly patients has become an urgent problem.AIM To investigate the trajectory of anxiety and depression levels in elderly patients after LIF,and the influencing factors.METHODS Random sampling was used to select 239 elderly patients who underwent LIF from January 2020 to December 2024 in Shenzhen Pingle Orthopedic Hospital.General information and surgery-related indices were recorded,and participants completed measures of psychological status,lumbar spine dysfunction,and quality of life.A latent class growth model was used to analyze the post-LIF trajectory of anxiety and depression levels,and unordered multi-categorical logistic regression was used to analyze the influencing factors.RESULTS Three trajectories of change in anxiety level were identified:Increasing anxiety(n=26,10.88%),decreasing anxiety(n=27,11.30%),and stable anxiety(n=186,77.82%).Likewise,three trajectories of change in depression level were identified:Increasing depression(n=30,12.55%),decreasing depression(n=26,10.88%),and stable depression(n=183,76.57%).Regression analysis showed that having no partner,female sex,elevated Oswestry dysfunction index(ODI)scores,and reduced 36-Item Short Form Health Survey scores all contributed to increased anxiety levels,whereas female sex,postoperative opioid use,and elevated ODI scores all contributed to increased depression levels.CONCLUSION During clinical observation,combining factors to predict anxiety and depression in post-LIF elderly patients enables timely intervention,quickens recovery,and enhances quality of life.展开更多
This study investigates climate-and human-induced hydrological changes in the Zavkhan River-Khyargas Lake Basin,a highly sensitive arid and semi-arid region of Central Asia.Using Mann-Kendall,innovative trend analysis...This study investigates climate-and human-induced hydrological changes in the Zavkhan River-Khyargas Lake Basin,a highly sensitive arid and semi-arid region of Central Asia.Using Mann-Kendall,innovative trend analysis,and Sen's slope estimation methods,historical climate trends(1980-2100)were analyzed,while land cover changes represented human impacts.Future projections were simulated using the MIROC model with Shared Socioeconomic Pathways(SSPs)and the Tank model.Results show that during the past 40 years,air temperature significantly increased(Z=3.93^(***)),while precipitation(Z=-1.54^(*))and river flow(Z=-1.73^(*))both declined.The Khyargas Lake water level dropped markedly(Z=-5.57***).Land cover analysis reveals expanded cropland and impervious areas due to human activity.Under the SSP1.26 scenario,which assumes minimal climate change,air temperature is projected to rise by 2.0℃,precipitation by 21.8 mm,and river discharge by 1.61 m^(3)/s between 2000 and 2100.These findings indicate that both global warming and intensified land use have substantially altered hydrological and climatic processes in the basin,highlighting the vulnerability of western Mongolia's water resources to combined climatic and anthropogenic influence.展开更多
Glacier landslide cascading hazards pose threats to communities and infrastructure,affected by complex processes including the amplification of mass flow volume through erosion and entrainment,transformation of hazard...Glacier landslide cascading hazards pose threats to communities and infrastructure,affected by complex processes including the amplification of mass flow volume through erosion and entrainment,transformation of hazard types,ice-water phase change,and enhanced mobility of the mass flow.Scientifically simulating these physical phenomena proves challenging.This study introduces GMFA(glacier mass flow analysis),an integrated numerical model that advances the field by:(1)proposing depth-averaged fluctuation energy and internal energy equations,(2)incorporating the ice-water phase change and the entrainment-deposition process,and(3)capturing their effects on mass flow runout characteristics.The model employs the finite volume method to solve the multi-physics coupled governing equations,enabling efficient large-scale simulations.The model is verified through three numerical tests covering flow dynamics,temperature evolution,and thermo-hydro-mechanical runout processes.The model is applied to analyze a hazard chain that occurred on 10 September 2020 on the Tibetan Plateau.The multi-scenario simulation results indicate an entrained mass volume of(4.95±0.11)×10^(5)m^(3),and a ratio of entrained mass volume to source material volume of 0.44.The solid concentration decreases from 0.6-0.7 to 0.1-0.15 with increasing runout distance,indicating a transition from avalanche to debris flood.The internal energy rises by(3-4)×10^(3)kJ/m^(3),driving rapid ice melting from 0.1 to 0.2 to near-zero concentration.The model effectively quantifies volume amplification,ice-water phase changes,and multi-hazard transformations.This model pushes the geoscience frontier,extending computational capability from single-to multi-hazard simulations and providing a powerful tool for analyzing glacier cascading hazards.展开更多
The study on the interrelation between sea-level changes and biodiversity with its evolu-tion has great significance for understanding the impact of global changes on organic evolution and exploring the inherent laws ...The study on the interrelation between sea-level changes and biodiversity with its evolu-tion has great significance for understanding the impact of global changes on organic evolution and exploring the inherent laws of life-environment coevolution in geological history.In this paper,the stratigraphic distribution of fusulinacean fauna in the Carboniferous-Permian boundary section at Xikou,Zhen’an County,Shaanxi Province,is analyzed quantitatively,and the relationship between the species diversity of fusulinaceans and relative sea-level changes is discussed.As a whole,the spe-cies numbers of fusulinacean fauna experience a rapid increase and an obvious decline in Xikou,Zhen’an County,from the Late Carboniferous to the Early Permian.There is a significant increase in species diversity around the Carboniferous-Permian boundary,which is one of the biggest bio-events of the fusulinacean fauna,and represents the radiation of Pseudoschwagerininae subfamily in the studied area.Integrated fusulinacean species diversity into sequence stratigraphic framework,de-tailed study suggests that the species diversity of the fusulinaceans is closely related to its relative stratigraphic location,and is essentially controlled by the sea-level changes,especially by the high-frequency sea-level changes.Generally,the species diversity of fusulinaceans is low,and the number of first and last appearance datum is small in the lower unit of high-frequency depositional cycle formed during the quick rise of the sea level;whereas the species diversity of fusulinaceans is high,and the number of first and last appearance datum is large in the upper unit of high-frequency cycle formed during the slow fall of the sea level.Within the third-order depositional sequence,the species diversity of the fusulinaceans at the first flooding surfaces and the maximum flooding surfaces is low,and it increases upward.The fusulinacean species diversity is low within the transgressive systems track,and it is high within the highstand systems track.The second-order rise and fall in sea level coincide with the bloom and decline of high order taxa of fusulinaceans.展开更多
This paper presents magnetic susceptibility results of 578 samples from three De-vono-Carboniferous carbonate successions in the Yangtze Block. They indicate that the magnetic susceptibility variations in carbonates a...This paper presents magnetic susceptibility results of 578 samples from three De-vono-Carboniferous carbonate successions in the Yangtze Block. They indicate that the magnetic susceptibility variations in carbonates are controlled by ancient sea-level changes. It is particularly so if the supply of detrital materials was low, when the magnetic susceptibility was mainly controlled by the content of authigenic minerals. If the supply of detrital materials was high, the average susceptibility value would be higher, but there is still a correlation between susceptibility and sea-level curves. A sea level rise would lead to a decrease in the content of the detrital materials, and therefore to a decrease in the susceptibility values. On the top of HST, the uplift and exposure events may lead to elevated magnetic susceptibility values. Carbonate susceptibilities can therefore be considered as one of the environmental proxy data for the research of sequence stratigraphy.展开更多
文摘Gas-bearing shales have become a major source of future natural gas production worldwide.It has become increasingly urgent to develop a reliable prediction model and corresponding workflow for identifying shale gas sweet spots.The formation of gas-bearing shales is closely linked to relative sealevel changes,providing an important approach to predicting sweet spots in the Wufeng-Longmaxi shale in the southern Sichuan Basin,China.Three types of marine shale gas sweet spots are identified in the shale based on their formation stages combined with relative sea-level changes:early,middle,and late transgression types.This study develops a prediction model and workflow for identifying shale gas sweet spots by analyzing relative sea-level changes and facies sequences.Predicting shale gas sweet spots in an explored block using this model and workflow can provide a valuable guide for well design and hydraulic fracturing,significantly enhancing the efficiency of shale gas exploration and development.Notably,the new prediction model and workflow can be utilized for the rapid evaluation of the potential for shale gas development in new shale gas blocks or those with low exploratory maturity.
文摘Abstract Experimental examinations and analyses have been made of the sediments from drill holes in the Zhuhai area, Guangdong Province. The studies show that there occurred four transgressions in this area over the historical times. The first transgression occurred at 7500 a B.P., with the maxium sea level up to about 1 m above the present level. The second transgression occurred at 5750 a B.P., with the sea level possibly 4 m higher than the present. The third and fourth transgressions took place at 4650 a B.P. and 2600 a B.P. respectively, which lasted for a long time with multiple fluctuations. The fifth transgression is in process. It could be predicted that the sea level at Zhuhai would rise by 15–20 cm in the coming 50 years.
文摘Several views on sea-level changes of the South China coast are briefly introduced in this paper. On the basis of 236 samples whose ages are determined by 14C chronological method and their sites are corrected with ancient water depth and crustal deformation, a basic model about sea-level changes of the South China coast since late Epipleistocene is set up. This model basically accords with the general cognitions of predecessors, i. e. it not only represents the common characteristics of sea-level changes of the East China coast but has some features of the South China coast itself. In general, this model is relatively close to the Fairbridge's curve, indicating that the sea-level undulations exist since 6 ka ago but the ranges of undulations are slightly larger than those of Fairbridge's curve.
基金sponsored by the National Natural Science Foundation of China(Nos.41672028 and 41672002)the 2020 Provincial Natural Science Foundation of Henan.
文摘Cambrian System at the Shatan Section in northern Henan,North China,consists of sedimentary successions of tidal flat and shallow-water carbonate platform facies.Data of carbon isotope(δ^(13)C_(carb))from this section reveals five positive δ^(13)C_(carb)(P_(st-1)-P_(st-5))and five negative δ^(13)C_(carb) excursions(N_(st-1)-N_(st-5)).In the positive excursions,δ^(13)C_(carb) rises to 0.88‰,1.05‰,2.04‰,1.00‰ and 2.97‰,respectively,while in the negative excursions δ^(13)C_(carb) drops to -8.00‰,-3.50‰,-1.00‰,-0.33‰ and around -2.00‰,respectively.On the basis of chronostratigraphy of Cambrian,the most remarkable carbon isotope excursions can be correlated regionally and globally.In addition,one second-order and ten third-order sequences have been recognized at this section.Correlating third-order sequences and chemostratigraphy indicates that carbonates from the basal part of the transgression system tract(TST)and the upper part of the high-water system(LHST)generally have lighter δ^(13)C_(carb) values,whereas massive carbonates with microbialite from the lower part of the high-water system tract(EHST)usually have heavier δ^(13)C_(carb) values.The association of δ^(13)C_(carb) values with sea-level fluctuations suggests that the positive carbon isotope excursions or high δ^(13)C_(carb) values may have been caused by an increase in the marine primary productivity in response to maximum seawater flooding during the transgression.
基金This paper is financially supported by the National Natural ScienceFoundation of China (No .40172014)the Chinese Academy of Sciences(No . KZCX3-SW-143)the Ministry of Science and Technology ofChina (No .2002CB412602) .
文摘The platform-facies carbonate rocks of the Carboniferous-Permian boundary strata are well developed and outcropped in Xikou （西口）, Zhen＇an （镇安） County, Shaanxi （ 陕西 ） Province, China. The carbonate diagencsis in the Carboniferous-Permian boundary section at Xikou contains many processes with conspicuous effects, including micritization, cementation, mechanical and chemical compaction, neomorphism, and dissolution. Based on mineralogical composition and microfabrics, the diagenetic environments are distinguished into marine, near surface meteoric and burial environments. Detailed petrographical observation of abundant thin sections integrated with previous studies on sequence stratigraphy reveals that the carbonate diagenesis in the Carboniferous-Permian boundary section is related to the relative stratigraphic position of the rocks in the high-frequency cycles and controlled by the glacioeustatic sea-level changes. There are distinctive differences in diagenetic patterns between the lower transgressive sequence and the upper regressive sequence in a cyclothem. The diagenesis in the lower transgressive sequence is mainly characterized by pressure dissolution and recrystallization of mudstone and wackstone in a burial environment, and the diagenesis in the upper regressive sequence by cementation and leaching of freshwater in a meteoric environment.
基金This paper was supported by Natural Science Foundation of Fujian Provinice(No. D88010)
文摘The sedimentary sequences since the Late Pleistocene can be divided into Layers E, D, C, B, A from old to young according to systematic analysis of grain-size, pollen and spore, diatom, foraminifera, radiocarbon dating and paleogeomagnetism of 16 sedimentary cores from the sea area of the western Taiwan Strait. The results proved the existences of the Langqi transgression (upper section of Layer D) formed in middle and late stages of early Wurm glacial period, Fuzhou transgression (Layer C) formed in Wurm sub-interglacial period and Changle transgression (Layer A) formed in postglacial period. It was also the first time to discover the Jinmen transgression (Layer E) formed in Riss -Wurm interglacial period. In this paper it is proposed that most part of the Taiwan Strait emerged as land in the early stage of early Wurm glacial period, and was still under sublittoral environment in late Wurm glacial period, as well as the existence of Dongshan Continental Bridge was in 8×103 a BP.
基金the National Natural Science Foundation of China (Nos.41776065,41576050,41830539)the Basic Scientific Fund for National Public Research Institutes of China (Nos.2019S04,2017Y07)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42000000)the Open Fund of Qingdao National Laboratory for Marine Science and Technology (No.QNLM20160RP0205)
文摘Detrital sediments derived from the Philippine Islands are one of the main sources of deep-sea sediments in the western Philippine Sea.However,systematic research on their characteristics and transport mechanisms are lacking.We used parametric end-member analysis to quantitatively partition the grain size of detrital sediments in core MD06-3052 from the Bicol Shelf in the western Philippine Sea;three endmembers EMI,EM2,and EM3,whose respective modes were at 2,10,and 45 μm,were separated.We also measured the Sr and Nd isotopic compositions of different size fractions(<4 and >20 μm) of the detrital sediments and the results showed that the detrital sediments mainly originate from the Philippine Islands.Components EMI and EM2 are transported to the Bicol Shelf mainly by surface and bottom currents from the islands,and component EM3 is delivered by gravity flow from the exposed shelf during low sea-level stands.The content of the total detrital fraction and the three end-members,as well as the mass accumulation rates(MARs) of the coarse detritus(EM2 and EM3),were considerably higher during glacial periods(40-14 ka and 150-130 ka) than during other intervals;the glacials corresponded to a low sea level,while the MAR of the fine detritus(EMI) did not increase remarkably during 40-14 ka.We therefore concluded that the input of coarse detritus to the Bicol Shelf from the islands was mainly controlled by sea-level change.Variations of the input of fine-grained detritus(EM1) was influenced not only by sea level but also by ocean currents and regional precipitation.Overall,our results help understand "source-to-sink" processes in the western Pacific marginal seas and their response to global change.
基金granted by UNESCO-IUGS IGCP program(IGCP609)the International programs(ESS)of the Austrian Academy of Sciencesthe National Natural Science Foundation of China(NSFC)for Distinguished Young Scholar(41525007).
文摘Anthropogenic global warming and resulting sea-level rise in response to enhanced atmospheric greenhouse gases and melting of the Earth’s continental ice shields have become issues of continuously growing interest for the scientific community as well as the public,pointing to threads of societies in a future greenhouse Earth System.
文摘-On the basis of the data obtained from the investigations on some rivers in China and Australia, the author discusses the spatial and temporal changes of various portions of fluvial-estuarine system during postglacial sea-level rising in present coastal and deltaic areas. The evolution of a fluvial-estuarine system can be divided into four development stages: early transgression, late transgression, stationary and regression. Early transgression brought about filling-in of the paleo-valley formed in low stand of sea level. In response to late transgression the estuaries were created, during the stationary stage the big swamp was developed. The regression led to estuaries to be filled with sediments and then became deltas. At the same locality the fluvial-estuarine system changed with time. In the transgressive period the lower reach of a river changed into an estuary, and then became nearshore area. In the regressive period the nearshore area changed into an estuary , and then became delta.
基金the University of French Polynesiafunding by several successive“Decision Aide a la Recherche”(DAR)grants to the Geodesy Observatory of Tahiti from the French Space Agency(CNES)+2 种基金fundings from the local government of French Polynesia(Observatoire Polynesien du Rechauffement Climatique)funding by“National Natural Science Foundation of China”(Grand No.41931075)funding by“the Fundamental Research Funds for the Central Universities"(Grand No.2042022kf1198)。
文摘In this study,we estimate the absolute vertical land motions at three tidal stations with collocated Global Navigation Satellite System(GNSS)receivers over French Polynesia during the period 2007-2020,and obtain,as ancillary results,estimates of the absolute changes in sea level at the same locations.To verify our processing approach to determining vertical motion,we first modeled vertical motion at the International GNSS Service(IGS)THTI station located in the capital island of Tahiti and compared our estimate with previous independent determinations,with a good agreement.We obtained the following estimates for the vertical land motions at the tide gauges:Tubuai island,Austral Archipelago-0.92±0.17 mm/yr,Vairao village,Tahiti Iti:-0.49±0.39 mm/yr,Rikitea,Gambier Archipelago-0.43±0.17 mm/yr.The absolute variations of the sea level are:Tubuai island,Austral Archipelago 5.25±0.60 mm/yr,Vairao village,Tahiti Iti:3.62±0.52 mm/yr,Rikitea,Gambier Archipelago 1.52±0.23 mm/yr.We discuss these absolute values in light of the values obtained from altimetric measurements and other means in French Polynesia.
基金supported by the National Key R&D Plan“Inter-governmental International Science&Technology Innovation Cooperation”Key Specialized Program,China(2025YFE0102800)the Program of the State Key Laboratory of Cryospheric Science and Frozen Soil Engineering,Chinese Academy of Sciences(CSFSE-ZZ-2403).
文摘Tajikistan contains the majority of Central Asia’s glaciers,which cover about 6.00%of the national territory;their rapid shrinkage poses a significant threat to regional water resource security.However,glacier monitoring in Tajikistan was interrupted after 1991,creating a substantial gap in understanding the current state and temporal evolution of these glaciers.Based on glacier inventory data,in situ measurements,and published literature,this study examined the present status and recent variations of glaciers in Tajikistan through data integration and validation,literature collation and comparative analysis,and the application of Geographic Information System(GIS)spatial analysis techniques.As of 2023,Tajikistan possesses a total of 11,528 glaciers,encompassing an area of 7624.48(±305.58)km2.Small glaciers dominate in number,whereas large glaciers account for the majority of the total area.Over the past two decades,the glacier count has decreased by 2014,and the total area has decreased by 628.98 km2,corresponding to an average annual reduction rate of 0.33%.Regional shrinkage rates range from 4.10%to 22.28%.Glaciers have undergone accelerated mass loss during the past 20 a;only those on the northeastern Pamir Plateau exhibit a weak positive mass balance.Observations of typical monitored glaciers also reveal intensified melting and retreat,consistent with regional trends.In light of the recent acceleration of glacier shrinkage in Tajikistan,focused measures should be implemented to strengthen glacier monitoring,enhance public awareness of glacier preservation,and promote the sustainable development and utilization of glacier tourism.These findings bridge the knowledge gap regarding the spatiotemporal dynamics of Tajikistan’s glaciers over recent decades and provide essential data support for regional water resource management.
基金Supported by Changsha Tobacco Company Science and Technology Project(2020-2024A04).
文摘Starting from the foundational static traits underlying the growth and development of flue-cured tobacco, this research conducts a systematic examination of the phenomena and theoretical principles associated with environment-driven adaptive changes during its cultivation. It was found that environmental variables-including temperature, light, and moisture-elicit directional shifts in static traits ( e.g. , chemical composition, morphological architecture, and leaf tissue structure) toward enhanced environmental adaptation, characterized by graduality, juvenility, similarity, and correlativity. Upon alterations in ambient conditions, flue-cured tobacco modulates its static traits through integrated physical, chemical, and biological-genetic mechanisms, aiming to optimize resource utilization, mitigate environmental constraints, and preserve internal homeostasis alongside metabolic balance. The investigation further reveals that the adaptive scope of flue-cured tobacco to field environments is malleable and can be extended and elevated via adaptive conditioning commencing at the juvenile stage. In addition, the adaptive alignment between static traits and environmental parameters exerts a substantial impact on the plant s growth dynamics, yield performance, and quality attributes. Beyond its relevance to flue-cured tobacco, the proposed theory offers a meaningful framework for elucidating the pervasive adaptive strategies employed by plants and broader biological systems in response to environmental contingencies.
基金Construction Project of High-Level Traditional Chinese Medicine Key Discipline of National Administration of Traditional Chinese Medicine,Grant/Award Number:zyyzdxk-2023022Key Team of Scientific and Technological Innovation Talents of Shanxi Province with Integrated Traditional Chinese and Western Medicine for Preventing and Treating Rheumatological Diseases,Grant/Award Number:202204051002033+4 种基金Traditional Chinese Medicine+Stem Cell Innovation Project,Grant/Award Number:2024KJZY0062023 Shanxi Graduate Research Practice Project,Grant/Award Number:2023KY6762023 Graduate Innovation and Entrepreneurship Project of Shanxi University of Traditional Chinese Medicine,Grant/Award Number:2023CX023 and 2023CX027Science and Technology Innovation Project for University in Shanxi Province,Grant/Award Number:2022L358Key Laboratory of Rheumatological and Immunological Diseases Treated by Integrated Chinese and Western Medicine,Grant/Award Number:zyyyjs2024021。
文摘Knee osteoarthritis(KOA)is a chronic degenerative disease.Monosodium iodoac-etate(MIA)induction is the most commonly used therapeutic effect evaluation and mechanism of action research model;we observed a lack of standardization and uni-formity in current model building methods,which led us to conduct this study.Background:The aim was to investigate the time-and dose-related changes in the behavioral and pathological characteristics in the MIA-induced KOA model rat.Methods:MIA(40,50,and 60 mg/mL)was injected into the left joint of male Sprague-Dawley rats.After 2 weeks,the changes in the KOA rat model were observed by be-havioral evaluation,imaging-level evaluation,and histological-level evaluation.The changes were also compared after 40-mg/mL MIA injection for 2 and 6 weeks.Results:MIA-induced bone surface defects,osteophyte hyperplasia around the artic-ular rim,increased subchondral bone density,thinning of the sparse trabecular bone,structural disorder,and local clustering were observed.The degree of injury gradually increased with the increase in MIA concentration.After 6 weeks,subchondral bone density and sparse trabecular bone increased in the KOA model.Conclusions:The severity of the model also increased significantly with the changes in dose and time.In dose-dependent experiments,this study revealed that 40 mg/mL was the optimal dose to induce significant pathological changes without causing undue discomfort or death in animals.This dose may induce pathological changes stably and is suitable for long-term observation.
文摘Lin Wei is a hiking enthusiast.At six o'clock on the last Saturday morning,the temperature at the foot of the mountain was only 2℃,so she put on her thickest fleece jacket.However,after only half an hour of climbing,the heat left her drenched in sweat,making her feel very cold.By midday,the temperature was approaching 20℃,and her heavy jacket had to be tied around her waist,becoming a burden during her hike.This outdoor adventure allowed her to appreciate the beautiful scenery,but also subjected her to repeated changes in temperature.
文摘In recent years,against the backdrop of profound geopolitical changes,the European Union(EU)has been deeply mired in an industrial predicament,showing signs of shrinking production,capital outflows,relocation of production capacity,and lagging development in future industries.The primary causes of this situation include the energy supply crisis stemming from the decoupling from Russian energy,the impact of America's unilateral trade policy,structural flaws within the EU itself,and the intensification of global industrial competition.To overcome these challenges,the EU has introduced a series of new industrial policies,aiming at revitalizing its industries by strengthening support for local manufacturing,enhancing protective mechanisms for its domestic production,building diversified supply chains,and prioritizing the development of military industry.However,due to multiple obstacles such as heavy external dependence,significant funding gaps,internal divisions,and strategic short-sightedness,the EU still faces a long and arduous journey in its industrial revival.
基金Supported by the Scientific Research Projects of the Health System in Pingshan District,No.2023122.
文摘BACKGROUND Lumbar interbody fusion(LIF)is the primary treatment for lumbar degenerative diseases.Elderly patients are prone to anxiety and depression after undergoing surgery,which affects their postoperative recovery speed and quality of life.Effective prevention of anxiety and depression in elderly patients has become an urgent problem.AIM To investigate the trajectory of anxiety and depression levels in elderly patients after LIF,and the influencing factors.METHODS Random sampling was used to select 239 elderly patients who underwent LIF from January 2020 to December 2024 in Shenzhen Pingle Orthopedic Hospital.General information and surgery-related indices were recorded,and participants completed measures of psychological status,lumbar spine dysfunction,and quality of life.A latent class growth model was used to analyze the post-LIF trajectory of anxiety and depression levels,and unordered multi-categorical logistic regression was used to analyze the influencing factors.RESULTS Three trajectories of change in anxiety level were identified:Increasing anxiety(n=26,10.88%),decreasing anxiety(n=27,11.30%),and stable anxiety(n=186,77.82%).Likewise,three trajectories of change in depression level were identified:Increasing depression(n=30,12.55%),decreasing depression(n=26,10.88%),and stable depression(n=183,76.57%).Regression analysis showed that having no partner,female sex,elevated Oswestry dysfunction index(ODI)scores,and reduced 36-Item Short Form Health Survey scores all contributed to increased anxiety levels,whereas female sex,postoperative opioid use,and elevated ODI scores all contributed to increased depression levels.CONCLUSION During clinical observation,combining factors to predict anxiety and depression in post-LIF elderly patients enables timely intervention,quickens recovery,and enhances quality of life.
基金The National University of Mongolia,No.P2024-4814The Mongolian Science and Technology Foundation,No.CHN-2022/274The‘Chey Institute for Advanced Studies’International Scholar Exchange Fellowship for the Academic Year of 2025-2026。
文摘This study investigates climate-and human-induced hydrological changes in the Zavkhan River-Khyargas Lake Basin,a highly sensitive arid and semi-arid region of Central Asia.Using Mann-Kendall,innovative trend analysis,and Sen's slope estimation methods,historical climate trends(1980-2100)were analyzed,while land cover changes represented human impacts.Future projections were simulated using the MIROC model with Shared Socioeconomic Pathways(SSPs)and the Tank model.Results show that during the past 40 years,air temperature significantly increased(Z=3.93^(***)),while precipitation(Z=-1.54^(*))and river flow(Z=-1.73^(*))both declined.The Khyargas Lake water level dropped markedly(Z=-5.57***).Land cover analysis reveals expanded cropland and impervious areas due to human activity.Under the SSP1.26 scenario,which assumes minimal climate change,air temperature is projected to rise by 2.0℃,precipitation by 21.8 mm,and river discharge by 1.61 m^(3)/s between 2000 and 2100.These findings indicate that both global warming and intensified land use have substantially altered hydrological and climatic processes in the basin,highlighting the vulnerability of western Mongolia's water resources to combined climatic and anthropogenic influence.
基金supports from the National Natural Science Foundation of China(Grant No.U20A20112)the Research Grants Council of the Hong Kong SAR Government,China(Grant Nos.T22-606/23-R and 16206923).
文摘Glacier landslide cascading hazards pose threats to communities and infrastructure,affected by complex processes including the amplification of mass flow volume through erosion and entrainment,transformation of hazard types,ice-water phase change,and enhanced mobility of the mass flow.Scientifically simulating these physical phenomena proves challenging.This study introduces GMFA(glacier mass flow analysis),an integrated numerical model that advances the field by:(1)proposing depth-averaged fluctuation energy and internal energy equations,(2)incorporating the ice-water phase change and the entrainment-deposition process,and(3)capturing their effects on mass flow runout characteristics.The model employs the finite volume method to solve the multi-physics coupled governing equations,enabling efficient large-scale simulations.The model is verified through three numerical tests covering flow dynamics,temperature evolution,and thermo-hydro-mechanical runout processes.The model is applied to analyze a hazard chain that occurred on 10 September 2020 on the Tibetan Plateau.The multi-scenario simulation results indicate an entrained mass volume of(4.95±0.11)×10^(5)m^(3),and a ratio of entrained mass volume to source material volume of 0.44.The solid concentration decreases from 0.6-0.7 to 0.1-0.15 with increasing runout distance,indicating a transition from avalanche to debris flood.The internal energy rises by(3-4)×10^(3)kJ/m^(3),driving rapid ice melting from 0.1 to 0.2 to near-zero concentration.The model effectively quantifies volume amplification,ice-water phase changes,and multi-hazard transformations.This model pushes the geoscience frontier,extending computational capability from single-to multi-hazard simulations and providing a powerful tool for analyzing glacier cascading hazards.
基金supported by the National Natural Science Foundation of China(Grant No.40172014)the Chinese Academy of Sciences(Grant No.KZCX3-SW-143).
文摘The study on the interrelation between sea-level changes and biodiversity with its evolu-tion has great significance for understanding the impact of global changes on organic evolution and exploring the inherent laws of life-environment coevolution in geological history.In this paper,the stratigraphic distribution of fusulinacean fauna in the Carboniferous-Permian boundary section at Xikou,Zhen’an County,Shaanxi Province,is analyzed quantitatively,and the relationship between the species diversity of fusulinaceans and relative sea-level changes is discussed.As a whole,the spe-cies numbers of fusulinacean fauna experience a rapid increase and an obvious decline in Xikou,Zhen’an County,from the Late Carboniferous to the Early Permian.There is a significant increase in species diversity around the Carboniferous-Permian boundary,which is one of the biggest bio-events of the fusulinacean fauna,and represents the radiation of Pseudoschwagerininae subfamily in the studied area.Integrated fusulinacean species diversity into sequence stratigraphic framework,de-tailed study suggests that the species diversity of the fusulinaceans is closely related to its relative stratigraphic location,and is essentially controlled by the sea-level changes,especially by the high-frequency sea-level changes.Generally,the species diversity of fusulinaceans is low,and the number of first and last appearance datum is small in the lower unit of high-frequency depositional cycle formed during the quick rise of the sea level;whereas the species diversity of fusulinaceans is high,and the number of first and last appearance datum is large in the upper unit of high-frequency cycle formed during the slow fall of the sea level.Within the third-order depositional sequence,the species diversity of the fusulinaceans at the first flooding surfaces and the maximum flooding surfaces is low,and it increases upward.The fusulinacean species diversity is low within the transgressive systems track,and it is high within the highstand systems track.The second-order rise and fall in sea level coincide with the bloom and decline of high order taxa of fusulinaceans.
文摘This paper presents magnetic susceptibility results of 578 samples from three De-vono-Carboniferous carbonate successions in the Yangtze Block. They indicate that the magnetic susceptibility variations in carbonates are controlled by ancient sea-level changes. It is particularly so if the supply of detrital materials was low, when the magnetic susceptibility was mainly controlled by the content of authigenic minerals. If the supply of detrital materials was high, the average susceptibility value would be higher, but there is still a correlation between susceptibility and sea-level curves. A sea level rise would lead to a decrease in the content of the detrital materials, and therefore to a decrease in the susceptibility values. On the top of HST, the uplift and exposure events may lead to elevated magnetic susceptibility values. Carbonate susceptibilities can therefore be considered as one of the environmental proxy data for the research of sequence stratigraphy.
