The Arno River Basin(Central Italy)is affected by a considerable anthropogenic pressure due to the presence of large cities and widespread industrial and agricultural practices.In this work,26 water samples from the A...The Arno River Basin(Central Italy)is affected by a considerable anthropogenic pressure due to the presence of large cities and widespread industrial and agricultural practices.In this work,26 water samples from the Arno River and its main tributaries were analyzed to assess the water pollution status.The geochemical composition of the Arno River changes from the source(dominated by a Ca-HCO_(3) facies)to the mouth(where a Na-Cl(SO4)chemistry prevails)with an increasing quality deterioration,as suggested by the Chemical Water Quality Index,due to anthropogenic contributions and seawater intrusion before flowing into the Ligurian Sea.The Ombrone and Usciana tributaries introduce anthropogenic pollutants into the Arno River,whilst Elsa tributary supplies significant contents of geogenic sulfate.The concentrations of dissolved nitrate and nitrite(up to 63 and 9 mg/L,respectively)and the respective isotopic values of𝛿15N and𝛿18O were also determined to understand origin and fate of the N-species in the Arno River Basin surface waters.The combined application of𝛿15N-NO_(3) and𝛿18O-NO_(3) and N-source apportionment modelling allowed the identification of soil organic nitrogen and sewage and domestic wastes as primary sources for dissolved NO_(3)-.The𝛿15N-NO_(2) and𝛿18O-NO_(2) values suggest that the nitrification process affects the ARB waters,thus controlling the abundances and proportion of the N-species.Our work indicates that additional efforts are needed to improve management strategies to reduce the release of nitrogenated species to the surface waters of the Arno River Basin,since little progress has been made from the early 2000s.展开更多
We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-...We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-2(SHANS2),a gas-filled recoil separator located at the China Accelerator Facility for Superheavy Elements(CAFE2).In total,20 decay chains are attributed to ^(288)Mc and 1 decay chain is assigned to ^(287)Mc.The measured oa-decay properties of ^(287,288)Mc as well as its descendants are consistent with the known data.No additional decay chains originating from the 2n or 5n reaction channels were detected.The excitation function of the ^(243)Am(^(48)Ca,3n)^(288)Mc reaction was measured at the cross-section level of picobarn,which indicates the promising capability for the study of heavy and superheavy nuclei at the facility.展开更多
Hydrocarbons are one of the important fluids within the Earth's crust,and different biotic and abitoic processes can generate hydrocarbon during geological periods.Tracing the sources and sinks of hydrocarbons can...Hydrocarbons are one of the important fluids within the Earth's crust,and different biotic and abitoic processes can generate hydrocarbon during geological periods.Tracing the sources and sinks of hydrocarbons can help us better understand the carbon cycle of the earth.In this study,an improved approach of adsorbed hydrocarbons extraction from sediments was established.The improved thermal desorption approach,compound-specific isotope analysis and position-specific isotope analysis were integrated to investigate the molecular and intramolecular isotope fractionation between trace hydrocarbon gases within sediments and geological hydrocarbon deposits.The isotopic compositions of the terminal position carbon of propane(δ^(13)C_(terminal))serves as a correlation indicator between trace hydrocarbon gases within sediments and geological hydrocarbon deposits.The tight sandstone gas from the Turpan-Hami Basin is a first case study for the application of this novel method to trace hydrocarbon origins.The results showed that the hydrocarbons in the tight sandstone gases in the study area most likely originated from humic organic matter(typeⅢkerogen)at an early mature stage.δ^(13)C_(terminal)values of the thermally desorbed propane gases from different source rocks were distinguishable and the values of the tight sandstone gases significantly overlap with those of the Lower Jurassic Sangonghe source rocks,suggesting their genetic relationship.Overall,the results provided novel position-specific carbon isotopic constraints on origins of hydrocarbons.展开更多
Prediction of production decline and evaluation of the adsorbed/free gas ratio are critical for determining the lifespan and production status of shale gas wells.Traditional production prediction methods have some sho...Prediction of production decline and evaluation of the adsorbed/free gas ratio are critical for determining the lifespan and production status of shale gas wells.Traditional production prediction methods have some shortcomings because of the low permeability and tightness of shale,complex gas flow behavior of multi-scale gas transport regions and multiple gas transport mechanism superpositions,and complex and variable production regimes of shale gas wells.Recent research has demonstrated the existence of a multi-stage isotope fractionation phenomenon during shale gas production,with the fractionation characteristics of each stage associated with the pore structure,gas in place(GIP),adsorption/desorption,and gas production process.This study presents a new approach for estimating shale gas well production and evaluating the adsorbed/free gas ratio throughout production using isotope fractionation techniques.A reservoir-scale carbon isotope fractionation(CIF)model applicable to the production process of shale gas wells was developed for the first time in this research.In contrast to the traditional model,this model improves production prediction accuracy by simultaneously fitting the gas production rate and δ^(13)C_(1) data and provides a new evaluation method of the adsorbed/free gas ratio during shale gas production.The results indicate that the diffusion and adsorption/desorption properties of rock,bottom-hole flowing pressure(BHP)of gas well,and multi-scale gas transport regions of the reservoir all affect isotope fractionation,with the diffusion and adsorption/desorption parameters of rock having the greatest effect on isotope fractionation being D∗/D,PL,VL,α,and others in that order.We effectively tested the universality of the four-stage isotope fractionation feature and revealed a unique isotope fractionation mechanism caused by the superimposed coupling of multi-scale gas transport regions during shale gas well production.Finally,we applied the established CIF model to a shale gas well in the Sichuan Basin,China,and calculated the estimated ultimate recovery(EUR)of the well to be 3.33×10^(8) m^(3);the adsorbed gas ratio during shale gas production was 1.65%,10.03%,and 23.44%in the first,fifth,and tenth years,respectively.The findings are significant for understanding the isotope fractionation mechanism during natural gas transport in complex systems and for formulating and optimizing unconventional natural gas development strategies.展开更多
Precipitation isotopes(δ^(18)O and δ^(2)H)are closely related to meteorological conditions for precipitation generation and the initial state of water vapor source areas,and are essential to the study of the regiona...Precipitation isotopes(δ^(18)O and δ^(2)H)are closely related to meteorological conditions for precipitation generation and the initial state of water vapor source areas,and are essential to the study of the regional hydrological cycle.The deuterium excess(d-excess)indicates deviation in isotope fractionation during evaporation and can trace water vapor sources.This study analyzed 443 precipitation samples collected from the Gannan Plateau,China in 2022 to assess precipitation isotope variations and their driving factors.Water vapor sources were evaluated using the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT),Concentration Weighted Trajectory(CWT),and Potential Source Contribution Factor(PSCF)models.Results showed that precipitation isotope values showed significant spatial and temporal variations on the Gannan Plateau.Temporally,precipitation isotope values peaked in June(when evaporation dominated)and minimized in March(depletion effect of air masses in the westerly wind belt).Spatially,the isotope values showed a distribution pattern of"high in the east and low in the west",which was mainly regulated by the differences in altitude and local meteorological conditions.Compared with the global meteoric water line(GMWL)with equation of δ^(2)H=8.00δ^(18)O+10.00,the slope and intercept of local meteoric water line(LMWL)for precipitation on the Gannan Plateau were smaller(7.49 and 7.63,respectively),reflecting the existence of a stronger secondary evaporation effect under the clouds in the region.The sources of water vapor on the Gannan Plateau showed significant seasonality and spatial heterogeneity.Specifically,the westerly belt and monsoon were the main water vapor transport paths at each sampling point,with Central Asian continental water vapor dominating in spring(53.49%),Indian Ocean water vapor dominating in summer(52.53%),Atlantic Ocean water vapor dominating in autumn(46.74%),and Atlantic Ocean and Mediterranean Sea water vapor dominating in winter(42.30%and 33.68%,respectively).Changes in the intensity of convective activity and Outgoing Longwave Radiation(OLR)affected the enrichment of isotopic values,which exhibited the same change trends as δ^(18)O.During the precipitation process,the δ^(18)O value first decreased and then increased.During the initial and final stages of precipitation process,precipitation was mainly influenced by continental air masses,while during the middle stage,it was controlled by marine air masses.The systematic research on precipitation isotopes and water vapor sources is important for climate change research and extreme precipitation prediction on the Gannan Plateau and other similar areas.展开更多
The Metal Stable Isotope Geochemistry Laboratory(MSIGL)at the University of Science and Technology of China has developed state-of-the-art analytical methods for twelve stable isotope systems,including Mg,Si,V,Fe,Cu,Z...The Metal Stable Isotope Geochemistry Laboratory(MSIGL)at the University of Science and Technology of China has developed state-of-the-art analytical methods for twelve stable isotope systems,including Mg,Si,V,Fe,Cu,Zn,Rb,Sr,Ag,Cd,Ba,and U.Geological and biological samples were first digested by acid dissolution or alkali dissolution.The target element was subsequently purified by the column chromatography method.A Neptune Plus MC-ICP-MS was used to measure isotope compositions and the isotope bias caused during measurements was calibrated by standard bracketing and/or the double spike method.The analytical procedure was carefully checked to ensure the high precision and accuracy of the data.Here,we summarized the protocol of these established methods and compiled the standard data measured at our lab as well as those reported in literature.This comprehensive dataset can serve as a reliable benchmark for calibration,method validation,and quality assurance in metal stable isotope analyses.展开更多
Hopane separation and isotope determination were conducted on 11 source rock samples from various sedimentary environments.A schematic diagram of the carbon isotope distributions of hopane across different depositiona...Hopane separation and isotope determination were conducted on 11 source rock samples from various sedimentary environments.A schematic diagram of the carbon isotope distributions of hopane across different depositional environments was constructed.By integrating biomarker and organic petrology evidence,the geological significance of hopane carbon isotopes in oil source correlation and paleoclimate and paleoecology reconstruction was revealed.The results showed that the carbon isotopic compositions of hopanes vary considerably with depositional environment.展开更多
0 INTRODUCTION Tin(Sn)deposits are genetically associated with reduced,crust-derived magmas where Sn is incompatible(as Sn^(2+))and tends to enrich in residual melts during magma evolution(e.g.,Lehmann,2021;Linnen et ...0 INTRODUCTION Tin(Sn)deposits are genetically associated with reduced,crust-derived magmas where Sn is incompatible(as Sn^(2+))and tends to enrich in residual melts during magma evolution(e.g.,Lehmann,2021;Linnen et al.,1995).In contrast,copper(Cu)deposits are typically related to oxidized,mantle-derived magmas where Cu is incompatible because sulfur(S)occurs as sulfate(e.g.,Deng et al.,2023;Sillitoe and Lehmann,2022;Jugo,2009).Thus,Sn and Cu mineralization are rarely coexisting in a single magmatic-hydrothermal deposit(Sillitoe and Lehmann,2022).展开更多
The tectonic evolution of Borneo and the affiliation between Southern and Northern Borneo remains unclear.The Rajang and Crocker Fan sediments,as one of the largest ancient submarine fans in Southeast Asia have witnes...The tectonic evolution of Borneo and the affiliation between Southern and Northern Borneo remains unclear.The Rajang and Crocker Fan sediments,as one of the largest ancient submarine fans in Southeast Asia have witnessed the tectonic evolution of Borneo since at least the late Mesozoic.In this study,we present laser ablation inductively coupled plasma mass spectrometer(LA-ICP-MS)U-Pb dating and Hf isotopic results of detrital zircons from the Trusmadi and Crocker formations within the Crocker Fan of Sabah,Northern Borneo.Our results,coupled with previous data,show that the Crocker Fan sediments in Sabah of Northern Borneo display similar age spectra to the Rajang Fan sediments in Sarawak of Central Borneo,with two major age clusters at 130-80 and 280-200 Ma.Further provenance analysis based on mineral shape with a prismatic characteristic and similar detrital zircon Hf isotopes of the two formations illustrates that the Jurassic-Cretaceous and partly Triassic detrital zircons of the Crocker and Rajang Fan sediments were derived from the erosion of contemporaneous magmatic rocks;part of Permian-Triassic ones could be the recycling of the Jurassic deposits in SW Borneo.The initial provenance of these Permian-Triassic detritus could be synchronous magmatic rocks in the Tin belt of the Malay Peninsula.Combining with previous data,we propose that the entire Borneo continent,including both Southern and Northern Borneo,developed a common Mesozoic continental magmatic arc.Moreover,we postulate that the Rajang and Crocker fans formed in a fore-arc extensional rift basin related to the retreat of the subducted Paleo-Pacific Plate beneath the Northern Borneo margin.展开更多
Sulfur isotopes of S-bearing materials are powerful tools to trace various geological processes and sulfur sources in earth sciences,especially in ore deposits where sulfide-sulfate pair coprecipitates widely.However,...Sulfur isotopes of S-bearing materials are powerful tools to trace various geological processes and sulfur sources in earth sciences,especially in ore deposits where sulfide-sulfate pair coprecipitates widely.However,in-situ S isotope determination of barite is challenging without natural matrix-matched reference material.In this study,we present two natural barite reference materials(1-YS and 294-YS)for in-situ sulfur isotopic analysis.Independent LA-MC-ICP-MS laboratories were utilized to test theδ34S micron-scale homogeneity of 1-YS and 294-YS barites that have 2s repeatabilities of better than±0.45‰and±0.41‰,respectively.Meanwhile,the in-situ analysis results are consistent with the results of the bulk analysis by GS-IRMS within uncertainty.The grand meanδ~(34)S values of 1-YS(13.37‰±0.42‰,2s)and 294-YS(14.38‰±0.44‰,2s)are the final recommended values obtained from four independent laboratories.All the results confirm the suitability of 1-YS and 294-YS barite used as calibration materials with respect to in-situ S isotopic analysis.Moreover,the new developed barite reference materials were used as matrix-matched standard to calibrate the barite samples from the Huayangchuan carbonatite-hosted U-polymetallic deposit(Qinling orogenic belt,western China)to obtainδ34S values.Utilizing the temperaturedependentδ34S fractionation of barite-pyrite pair,we calculate the formation temperature of barite(i.e.,506 to 537°C)and theδ34S value of mineralizing fluid(i.e.,-7.11‰to-7.59‰)in the Huayangchuan deposit.The results indicate an involvement of sedimentary sulfur,presumably acting as a potential uranium source(e.g.,upper crustal materials)for the giant Huayangchuan deposit.展开更多
Stable Sr isotopic composition(δ^(88/86)Sr)can be used to study magmatic processes,but their fractionation mechanism during magmatic evolution remains unclear.To understand the fractionation behaviors of the stable S...Stable Sr isotopic composition(δ^(88/86)Sr)can be used to study magmatic processes,but their fractionation mechanism during magmatic evolution remains unclear.To understand the fractionation behaviors of the stable Sr isotopes during magmatism,we report theδ^(88/86)Sr values of the Huili granitic pluton,which was subjected to intensive crystal-melt separation.The Huili pluton consists of K-feldspar granite and more evolved albite granite,and the albite granite exhibits significantly higherδ^(88/86)Sr values(+0.36‰to+0.52‰)than that of K-feldspar granite(+0.11‰to+0.25‰).K-feldspar,which contributes most of the Sr budget of the K-feldspar granite,has slightly lowerδ^(88/86)Sr values(−0.01‰to+0.17‰)than the whole rock.Theδ^(88/86)Sr variation of the Huili granites can be explained by separation of melt from K-feldspar-dominated crystals,because crystallization of K-feldspar can result in heavy Sr isotopic composition of the extracted interstitial melt.Stable Sr and Ba isotopic ratios in the Huili granites are highly coupled toward the heavy direction,refl ecting their similar element partitioning and isotope fractionation behaviors between the crystalline K-feldspar and melt.This study indicates that melt extraction plays a key role in granitic magma evolution.展开更多
In this study,we systematically explored the environmental significance of stable isotope characteristics and the controlling factors of precipitation stable isotopes in the source region of the Three Rivers(SRTR),the...In this study,we systematically explored the environmental significance of stable isotope characteristics and the controlling factors of precipitation stable isotopes in the source region of the Three Rivers(SRTR),the transitional zone of the Qinghai-Tibet Plateau in China.A total of 862 precipitation samples were collected from six fixed-point sampling locations between 2019 and 2021 in the SRTR.In June,the values of hydrogen(δD)and oxygen(δ^(18)O)stable isotopes were most enriched.The deuterium-excess(d-excess)in atmospheric precipitation was>0 in the SRTR;however,the maximum value of d-excess occurred in October.Moreover,the slopes of the local meteoric water line(LMWL)for Dari,Zaduo,Maduo,Qumalai,and Tuotuohe sites were lower than those of the global met-eoric water line(GMWL).In contrast,the slope of the LMWL for Zhimenda was higher than that of the GMWL.The altitude effects of oxygen(δ^(18)O)and hydrogen(δD)isotopes of precipitation were 0.70‰/100 m and 5.22‰/100 m,respectively.When the temperature was≤5℃,there was a significant temperature effect on stable oxygen isotope of precipitation(0.24‰/℃,P<0.05).Furthermore,even a minor increase(1%)in the weight of raindrops after falling results in a 0.82%rise in the evaporation enrichment rate ofδ^(18)O.Success-ive precipitation events also had a substantial influence on precipitation in the transitional region of the Qinghai-Tibet Plateau.The res-ults of this study provide a theoretical basis for revealing the impact mechanism of precipitation in the transitional zone of the Qinghai-Tibet Plateau under a warming climate.展开更多
Marine carbonates,the major carrier of carbon upon the upper crust,can be subducted into the Earth’s interior along with oceanic crust,and then returned to the surface through magmatism,which constitute the deep carb...Marine carbonates,the major carrier of carbon upon the upper crust,can be subducted into the Earth’s interior along with oceanic crust,and then returned to the surface through magmatism,which constitute the deep carbon cycle.This process plays an important role in modulating the CO_(2) concentrations in the atmosphere over geologic time,and thus the forming of the habitable earth.Therefore,identifying recycled marine carbonates in the mantle is critical to well understand the global deep carbon cycle.Calcium is one of the major constituent cations in marine carbonates and its isotopes may be a potential tracer for recycled marine carbonates in the mantle.To further evaluate the capability and challenges of Ca isotopes as such a geochemical tracer,we reviewed the Ca isotopic compositions in important reservoirs and the behavior of Ca isotopes during high-temperature geological processes that are related to the deep carbon cycle,including plate subduction,mantle metasomatism,mantle partial melting,magma differentiation,etc.Available studies show that carbonate-rich marine sediments have significantly lowerδ^(44/40) Ca than the Earth mantle,and metasomatism by such recycled materials can cause lighter Ca isotopic compositions in deep mantle-derived rocks than those of the depleted mantle and mid ocean ridge basalts.However,the Ca isotopic fractionation during partial melting of mantle peridotites is small(~0.10‰)and the Ca isotopic fractionation during plate subduction and intermediate-mafic magma evolution is indistinguishable.These investigations suggest that Ca isotopes have great advances in tracing such recycled materials in the mantle.However,other processes(such as the influence by partial melts of eclogites)may induce similar effects on mantle-derived rocks as subducted marine carbonates but still remains debated,and thus further investigations are strongly needed in the future.展开更多
The methane adsorption capacity,gas content,and carbon isotope characteristics of coal are crucial parameters that determine the productivity of coalbed methane(CBM)wells and their development potential.In this paper,...The methane adsorption capacity,gas content,and carbon isotope characteristics of coal are crucial parameters that determine the productivity of coalbed methane(CBM)wells and their development potential.In this paper,test analyses of methane adsorption,gas content and carbon isotope of methane were carried out using 89 samples from the No.3 coal seam in the southwestern part of the Qinshui Basin.Their characteristics and correlations were analyzed.A relationship model between methane adsorption,gas content,carbon isotopes,coal metamorphism and material composition were established,and its controlling mechanism was investigated.The results indicate that the distribution patterns of Langmuir volume and Langmuir pressure in No.3 coal seam are mainly determined by the material composition and the thermal evolution level.The methane gas content in coal is mainly affected by the burial depth,microcosmic co mposition,mineral conte nt,moisture content and ash yield,adsorption capacity and metamorphism of the coal.The methane carbon isotope(δ^(13)C_(1))values in the natural desorbed gas from No.3 coal seam range from-26.95%to-57.80‰,with a mean value of-34.53‰.δ^(13)C_(1)in coal shows a two-stage variation pattern with increasing in vitrinite reflectance(R_(max)^(o)).When R_(max)^(o)is blow 3.0%,δ^(13)C_(1)values of methane in coal become progressively heavier with increasing R_(max)^(o).When R_(max)^(o)reaches or exceeds 3.0%,δ^(13)C_(1)values exhibit a lightning trend with furth er increases in R_(max)^(o),which is primarily controlled by the carbon isotope fractionation effects during thermal evolution.展开更多
Coal power plants annually generate quantities of byproducts that release environmentally hazardous heavy metals like Cd and Pb.Understanding the behavior and spatiotemporal impacts on soils of these releases is cruci...Coal power plants annually generate quantities of byproducts that release environmentally hazardous heavy metals like Cd and Pb.Understanding the behavior and spatiotemporal impacts on soils of these releases is crucial for pollution control.This study investigated the concentrations and isotope ratios of Cd/Pb in combustion byproducts,depositions and soils collected froma coal-fired power plant or its surrounding area.The pulverized fuel ash(PFA)and desulfurized gypsum(DG)exhibited heavier Cd isotopes withΔ^(114)Cd values of 0.304‰and 0.269‰,respectively,while bottom ash(BA)showed lighter Cd isotopes(Δ^(114)CdBA-coal=–0.078‰),compared to feed coal.We proposed a two-stage condensation process that governs the distribution of Cd/Pb,including accumulation on PFA and DG within electrostatic precipitators and desulfurization unit,as well as condensation onto fine particles upon release from the stack.Emissions from combustion and large-scale transport make a significant contribution to deposition,while the dispersion of Cd/Pb in deposition is primarily influenced by the prevailing wind patterns.However,the distribution of Cd/Pb in soils not only exhibit predominant wind control but is also potentially influenced by the resuspension of long-term storage byproducts.The power plant significantly contributes to soil in the NW–N–NE directions,even at a considerable distance(66%–79%),demonstrating its pervasive impact on remote regions along these orientations.Additionally,based on the vertical behavior in the profile,we have identified that Cd tends to migrate downward through leaching,while variations in Pb respond to the historical progression of dust removal.展开更多
Medical isotopes are the foundation material for nuclear medicine and are primarily produced through in-reactor irradia-tion.Neutron spectrum regulation is the main technical approach for enhancing the production of m...Medical isotopes are the foundation material for nuclear medicine and are primarily produced through in-reactor irradia-tion.Neutron spectrum regulation is the main technical approach for enhancing the production of medical isotopes,and it requires determining the optimal neutron spectrum and quantifying the values of neutrons in different energy regions.We calculated the neutron energy region values for 20 medical isotopes(^(14)C,^(32)P,^(47)Sc,^(60)Co,^(64)Cu,^(67)Cu,^(89)Sr,^(90)Y,^(99)Mo,^(125)I,^(131)I,^(153)Sm,^(161)Tb,^(166)Ho,^(177)Lu,^(186)Re,^(188)Re,^(92)Ir,^(225)Ac,and ^(252)Cf).The entire energy range was divided into 238 energy regions to improve the energy spectrum resolution,and both fast and thermal reactors were simulated to enhance universal applicability.A dataset of neutron energy region values across the entire energy range was built,which identifies the positive and negative-energy regions and guides the neutron spectrum regulation process during in-reactor medical isotope produc-tion.We conducted neutron spectrum regulation based on this dataset,which effectively improved the production efficiency of medical isotopes and demonstrated the correctness and feasibility of the dataset.展开更多
Extraterrestrial dust exhibits a wide range of textural,chemical and oxygen isotopic compositions due to the heterogeneity of their precursors and modification during atmospheric entry.Experimental heating provides an...Extraterrestrial dust exhibits a wide range of textural,chemical and oxygen isotopic compositions due to the heterogeneity of their precursors and modification during atmospheric entry.Experimental heating provides an opportunity to investigate the relationship between thermal processing and micrometeorite composition for a known precursor material.We conducted experiments to simulate the atmospheric entry of micrometeorites(MMs)using controlled,short-duration(10-50 s)flash heating(400-1600℃)of CI chondrite chips(<1500µm)in atmospheric air(1 bar,21%O2)combined with microanalysis(textures,chemical and isotopic compositions)of the experimental products.The heated chips closely resemble natural samples,with materials similar to unmelted MMs,partially melted(scoriaceous)MMs and fully melted cosmic spherules produced.We reproduced several key features such as dehydration cracks,magnetite rims,volatile gas release,vesicle formation and coalescence,melting and quench cooling.Our parameter space allows for discriminating peak temperature and heating duration effects.Peak temperature is the first-order control on MM mineralogy,while heating duration controls vesicle coalescence and homogenization.When compared against previous heating experiments,our data demonstrates that CI chondrite dust is more thermally resistant,relative to CM chondrite dust,by approximately+200℃.The 207 measurement of O-isotopes allows,for the first time,petrographic effects(such as volatile degassing and melting)to be correlated against bulk O-isotope evolution.Our results demonstrate findings applicable to CI chondrites and potentially to all fine-grained hydrated carbonaceous chondrite dust grains:(1)O-isotope variations arising during sub-solidus heating are dominated by the release of water from phyllosilicates,forcing the residual MM composition towards its anhydrous precursor composition.(2)Oxygen isotope compositions undergo the most significant changes at supra-solidus temperatures.As previously demonstrated and now empirically confirmed,most of these changes are driven by a mass-dependent fractionation effect caused by evaporation,which shifts residual rock compositions toward heavier values.Mixing with atmospheric air alters compositions toward the terrestrial fractionation line.Notably,these two processes do not begin simultaneously.Our data indicate that at 1200℃,isotopic evolution is dominated by evaporative mass loss.However,at higher temperatures(1400-1600℃),both pronounced evaporation and mixing with atmospheric oxygen become active,resulting in a more complex isotopic signature.(3)The total change in Δ17O during heating up to 1600℃is<3‰and in most scenarios<2‰.展开更多
Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not y...Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not yet fully understood.In this study,the V(V)reduction mechanisms with concomitant V isotope fractionation by the Gram-positive bacterium Bacillus subtilis(B.subtilis)and the Gramnegative bacterium Thauera humireducens(T.humireducens)were investigated.Both strains could effectively reduce V(V),removing(90.5%±1.6%)and(93.0%±1.8%)of V(V)respectively from an initial concentration of 50 mg L^(-1) during a 10-day incubation period.V(V)was bioreduced to insoluble vanadium(IV),which was distributed both inside and outside the cells.Electron transfer via cytochrome C,nicotinamide adenine dinucleotide,and glutathione played critical roles in V(V)reduction.Metabolomic analysis showed that differentially enriched metabolites(quinone,biotin,and riboflavin)mediated electron transfer in both strains.The aqueous V in the remaining solution became isotopically heavier as V(V)bioreduction proceeded.The obtained V isotope composition dynamics followed a Rayleigh fractionation model,and the isotope enrichment factor(e)was(–0.54‰±0.04‰)for B.subtilis and(–0.32‰±0.03‰)for T.humireducens,with an insignificant difference.This study provides molecular insights into electron transfer for V(V)bioreduction and reveals V isotope fractionation during this bioprocess,which is helpful for understanding V biogeochemistry and developing novel strategies for V remediation.展开更多
Taking deep coal-rock gas in the Yulin and Daning-Jixian areas of the Ordos Basin,NW China,as the research object,full-diameter coal rock samples with different cleat/fracture development degrees from the Carboniferou...Taking deep coal-rock gas in the Yulin and Daning-Jixian areas of the Ordos Basin,NW China,as the research object,full-diameter coal rock samples with different cleat/fracture development degrees from the Carboniferous Benxi Formation were selected to conduct physical simulation and isotope monitoring experiments of the full-life-cycle depletion development of coal-rock gas.Based on the experimental results,a dual-medium carbon isotope fractionation(CIF)model coupling cleats/fractures and matrix pores was constructed,and an evaluation method for free gas production patterns was established to elucidate the carbon isotope fractionation mechanism and adsorbed/free gas production characteristics during deep coal-rock gas development.The results show that the deep coal-rock gas development process exhibits a three-stage carbon isotope fractionation pattern:“Stable(Ⅰ)→Decrease(Ⅱ)→Increase(Ⅲ)”.A rapid decline in boundary pressure in stageⅢleads to fluctuations in isotope value,characterized by a“rapid decrease followed by continued increase”,with free gas being produced first and long-term supply of adsorbed gas.The CIF model can effectively match measured gas pressure,cumulative gas production,and δ^(13)C_(1) value of produced gas.During the first two stages of isotope fractionation,free gas dominated cumulative production.During the mid-late stages of slow depletion production,the staged pressure control development method can effectively increase the gas recovery.The production of adsorbed gas is primarily controlled by the rock's adsorption capacity and the presence of secondary flow channels.Effectively enhancing the recovery of adsorbed gas during the late stage remains crucial for maintaining stable production and improving the ultimate recovery factor of deep coal-rock gas.展开更多
The isotope effect on zonal flows(ZFs)and turbulence remains a key issue that is not completely solved in fusion plasmas.This paper presents the first experimental results of the ab initio prediction of causal relatio...The isotope effect on zonal flows(ZFs)and turbulence remains a key issue that is not completely solved in fusion plasmas.This paper presents the first experimental results of the ab initio prediction of causal relation between geodesic acoustic mode(GAM)and ambient turbulence at different isotope masses in the edge of HL-2A tokamak,where transfer entropy method based on information-theoretical approach is utilized as a quantified indicator of causality.Analysis shows that GAM is more pronounced in deuterium plasmas than in hydrogen,leading to a lower heat transport as well as more peaked profiles in the former situation.The causal impact of GAM on conductive heat flux component is stronger than on the convective component,which is resulted from a larger causal influence of zonal flow on temperature fluctuation.While a stronger GAM in deuterium plasmas has larger influence on all flux components,the relative change in temperature fluctuation and coefficient is more obvious when the ion mass varies.These findings not only offer an in-depth understanding of the real causality between zonal flow and turbulence in the present isotope experiments,but also provide useful ways for the physical understandings of transport and zonal flow dynamics in future deuterium-tritium fusion plasmas.展开更多
文摘The Arno River Basin(Central Italy)is affected by a considerable anthropogenic pressure due to the presence of large cities and widespread industrial and agricultural practices.In this work,26 water samples from the Arno River and its main tributaries were analyzed to assess the water pollution status.The geochemical composition of the Arno River changes from the source(dominated by a Ca-HCO_(3) facies)to the mouth(where a Na-Cl(SO4)chemistry prevails)with an increasing quality deterioration,as suggested by the Chemical Water Quality Index,due to anthropogenic contributions and seawater intrusion before flowing into the Ligurian Sea.The Ombrone and Usciana tributaries introduce anthropogenic pollutants into the Arno River,whilst Elsa tributary supplies significant contents of geogenic sulfate.The concentrations of dissolved nitrate and nitrite(up to 63 and 9 mg/L,respectively)and the respective isotopic values of𝛿15N and𝛿18O were also determined to understand origin and fate of the N-species in the Arno River Basin surface waters.The combined application of𝛿15N-NO_(3) and𝛿18O-NO_(3) and N-source apportionment modelling allowed the identification of soil organic nitrogen and sewage and domestic wastes as primary sources for dissolved NO_(3)-.The𝛿15N-NO_(2) and𝛿18O-NO_(2) values suggest that the nitrification process affects the ARB waters,thus controlling the abundances and proportion of the N-species.Our work indicates that additional efforts are needed to improve management strategies to reduce the release of nitrogenated species to the surface waters of the Arno River Basin,since little progress has been made from the early 2000s.
基金supported in part by the National Key R&D Program of China (Contract Nos.2023YFA1606500,2024YFE0109800,and 2024YFE0110400)Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB34010000)+5 种基金the Gansu Key Project of Science and Technology (Grant No.23ZDGA014)the Guangdong Major Project of Basic and Applied Basic Research (Grant No.2021B0301030006)the National Natural Science Foundation of China (Grant Nos.12105328,W2412040,12475126,12422507,12035011,12375118,12435008,and W2412043)the Chinese Academy of Sciences Project for Young Scientists in Basic Research(Grant No.YSBR-002)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant Nos.2020409 and 2023439)the Russian Science Foundation (Grant No.25-42-00003)。
文摘We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-2(SHANS2),a gas-filled recoil separator located at the China Accelerator Facility for Superheavy Elements(CAFE2).In total,20 decay chains are attributed to ^(288)Mc and 1 decay chain is assigned to ^(287)Mc.The measured oa-decay properties of ^(287,288)Mc as well as its descendants are consistent with the known data.No additional decay chains originating from the 2n or 5n reaction channels were detected.The excitation function of the ^(243)Am(^(48)Ca,3n)^(288)Mc reaction was measured at the cross-section level of picobarn,which indicates the promising capability for the study of heavy and superheavy nuclei at the facility.
基金financially supported by the National Natural Science Foundation of China(Grant No.42102202)U.S.Department of Energy Geosciences program(DE-SC0016271)。
文摘Hydrocarbons are one of the important fluids within the Earth's crust,and different biotic and abitoic processes can generate hydrocarbon during geological periods.Tracing the sources and sinks of hydrocarbons can help us better understand the carbon cycle of the earth.In this study,an improved approach of adsorbed hydrocarbons extraction from sediments was established.The improved thermal desorption approach,compound-specific isotope analysis and position-specific isotope analysis were integrated to investigate the molecular and intramolecular isotope fractionation between trace hydrocarbon gases within sediments and geological hydrocarbon deposits.The isotopic compositions of the terminal position carbon of propane(δ^(13)C_(terminal))serves as a correlation indicator between trace hydrocarbon gases within sediments and geological hydrocarbon deposits.The tight sandstone gas from the Turpan-Hami Basin is a first case study for the application of this novel method to trace hydrocarbon origins.The results showed that the hydrocarbons in the tight sandstone gases in the study area most likely originated from humic organic matter(typeⅢkerogen)at an early mature stage.δ^(13)C_(terminal)values of the thermally desorbed propane gases from different source rocks were distinguishable and the values of the tight sandstone gases significantly overlap with those of the Lower Jurassic Sangonghe source rocks,suggesting their genetic relationship.Overall,the results provided novel position-specific carbon isotopic constraints on origins of hydrocarbons.
基金supported by the Natural Science Foundation of China(Grant No.42302170)National Postdoctoral Innovative Talent Support Program(Grant No.BX20220062)+3 种基金CNPC Innovation Found(Grant No.2022DQ02-0104)National Science Foundation of Heilongjiang Province of China(Grant No.YQ2023D001)Postdoctoral Science Foundation of Heilongjiang Province of China(Grant No.LBH-Z22091)the Natural Science Foundation of Shandong Province(Grant No.ZR2022YQ30).
文摘Prediction of production decline and evaluation of the adsorbed/free gas ratio are critical for determining the lifespan and production status of shale gas wells.Traditional production prediction methods have some shortcomings because of the low permeability and tightness of shale,complex gas flow behavior of multi-scale gas transport regions and multiple gas transport mechanism superpositions,and complex and variable production regimes of shale gas wells.Recent research has demonstrated the existence of a multi-stage isotope fractionation phenomenon during shale gas production,with the fractionation characteristics of each stage associated with the pore structure,gas in place(GIP),adsorption/desorption,and gas production process.This study presents a new approach for estimating shale gas well production and evaluating the adsorbed/free gas ratio throughout production using isotope fractionation techniques.A reservoir-scale carbon isotope fractionation(CIF)model applicable to the production process of shale gas wells was developed for the first time in this research.In contrast to the traditional model,this model improves production prediction accuracy by simultaneously fitting the gas production rate and δ^(13)C_(1) data and provides a new evaluation method of the adsorbed/free gas ratio during shale gas production.The results indicate that the diffusion and adsorption/desorption properties of rock,bottom-hole flowing pressure(BHP)of gas well,and multi-scale gas transport regions of the reservoir all affect isotope fractionation,with the diffusion and adsorption/desorption parameters of rock having the greatest effect on isotope fractionation being D∗/D,PL,VL,α,and others in that order.We effectively tested the universality of the four-stage isotope fractionation feature and revealed a unique isotope fractionation mechanism caused by the superimposed coupling of multi-scale gas transport regions during shale gas well production.Finally,we applied the established CIF model to a shale gas well in the Sichuan Basin,China,and calculated the estimated ultimate recovery(EUR)of the well to be 3.33×10^(8) m^(3);the adsorbed gas ratio during shale gas production was 1.65%,10.03%,and 23.44%in the first,fifth,and tenth years,respectively.The findings are significant for understanding the isotope fractionation mechanism during natural gas transport in complex systems and for formulating and optimizing unconventional natural gas development strategies.
基金supported by the National Natural Science Foundation of China(42161007)the Innovation Foundation of Higher Education Institutions of Gansu Province(2021B-081)the Foundation for Distinguished Young Scholars of Gansu Province(20JR10RA112).
文摘Precipitation isotopes(δ^(18)O and δ^(2)H)are closely related to meteorological conditions for precipitation generation and the initial state of water vapor source areas,and are essential to the study of the regional hydrological cycle.The deuterium excess(d-excess)indicates deviation in isotope fractionation during evaporation and can trace water vapor sources.This study analyzed 443 precipitation samples collected from the Gannan Plateau,China in 2022 to assess precipitation isotope variations and their driving factors.Water vapor sources were evaluated using the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT),Concentration Weighted Trajectory(CWT),and Potential Source Contribution Factor(PSCF)models.Results showed that precipitation isotope values showed significant spatial and temporal variations on the Gannan Plateau.Temporally,precipitation isotope values peaked in June(when evaporation dominated)and minimized in March(depletion effect of air masses in the westerly wind belt).Spatially,the isotope values showed a distribution pattern of"high in the east and low in the west",which was mainly regulated by the differences in altitude and local meteorological conditions.Compared with the global meteoric water line(GMWL)with equation of δ^(2)H=8.00δ^(18)O+10.00,the slope and intercept of local meteoric water line(LMWL)for precipitation on the Gannan Plateau were smaller(7.49 and 7.63,respectively),reflecting the existence of a stronger secondary evaporation effect under the clouds in the region.The sources of water vapor on the Gannan Plateau showed significant seasonality and spatial heterogeneity.Specifically,the westerly belt and monsoon were the main water vapor transport paths at each sampling point,with Central Asian continental water vapor dominating in spring(53.49%),Indian Ocean water vapor dominating in summer(52.53%),Atlantic Ocean water vapor dominating in autumn(46.74%),and Atlantic Ocean and Mediterranean Sea water vapor dominating in winter(42.30%and 33.68%,respectively).Changes in the intensity of convective activity and Outgoing Longwave Radiation(OLR)affected the enrichment of isotopic values,which exhibited the same change trends as δ^(18)O.During the precipitation process,the δ^(18)O value first decreased and then increased.During the initial and final stages of precipitation process,precipitation was mainly influenced by continental air masses,while during the middle stage,it was controlled by marine air masses.The systematic research on precipitation isotopes and water vapor sources is important for climate change research and extreme precipitation prediction on the Gannan Plateau and other similar areas.
基金the National Science Foundation of China(Nos.42273007 and 42473008)the Distinguished Young Scholars of Anhui,China(No.2408085J021)。
文摘The Metal Stable Isotope Geochemistry Laboratory(MSIGL)at the University of Science and Technology of China has developed state-of-the-art analytical methods for twelve stable isotope systems,including Mg,Si,V,Fe,Cu,Zn,Rb,Sr,Ag,Cd,Ba,and U.Geological and biological samples were first digested by acid dissolution or alkali dissolution.The target element was subsequently purified by the column chromatography method.A Neptune Plus MC-ICP-MS was used to measure isotope compositions and the isotope bias caused during measurements was calibrated by standard bracketing and/or the double spike method.The analytical procedure was carefully checked to ensure the high precision and accuracy of the data.Here,we summarized the protocol of these established methods and compiled the standard data measured at our lab as well as those reported in literature.This comprehensive dataset can serve as a reliable benchmark for calibration,method validation,and quality assurance in metal stable isotope analyses.
基金funded by the Open Project of State Key Laboratory of Geological Process and Mineral Resources(GPMR−2022−07).
文摘Hopane separation and isotope determination were conducted on 11 source rock samples from various sedimentary environments.A schematic diagram of the carbon isotope distributions of hopane across different depositional environments was constructed.By integrating biomarker and organic petrology evidence,the geological significance of hopane carbon isotopes in oil source correlation and paleoclimate and paleoecology reconstruction was revealed.The results showed that the carbon isotopic compositions of hopanes vary considerably with depositional environment.
基金financially supported by the National Natural Science Foundation of China(Nos.42002080,42302092)the Guangxi Technology Base and Talent Project(No.Guike AD20238013)the Provincial Natural Science Foundation of Hunan(No.2024JJ5394)。
文摘0 INTRODUCTION Tin(Sn)deposits are genetically associated with reduced,crust-derived magmas where Sn is incompatible(as Sn^(2+))and tends to enrich in residual melts during magma evolution(e.g.,Lehmann,2021;Linnen et al.,1995).In contrast,copper(Cu)deposits are typically related to oxidized,mantle-derived magmas where Cu is incompatible because sulfur(S)occurs as sulfate(e.g.,Deng et al.,2023;Sillitoe and Lehmann,2022;Jugo,2009).Thus,Sn and Cu mineralization are rarely coexisting in a single magmatic-hydrothermal deposit(Sillitoe and Lehmann,2022).
基金jointly supported by the Scientific Research Foundation of Third Institute of Oceanography,Ministry of Natural Resources,Xiamen(No.2018002)the Guangxi Natural Science Fundation(No.2022GXNSFBA035588)+1 种基金the National Natural Science Foundation of China(Nos.41506050,41402193)the Scientific Research Foundation of Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration(No.19-185-17-09)。
文摘The tectonic evolution of Borneo and the affiliation between Southern and Northern Borneo remains unclear.The Rajang and Crocker Fan sediments,as one of the largest ancient submarine fans in Southeast Asia have witnessed the tectonic evolution of Borneo since at least the late Mesozoic.In this study,we present laser ablation inductively coupled plasma mass spectrometer(LA-ICP-MS)U-Pb dating and Hf isotopic results of detrital zircons from the Trusmadi and Crocker formations within the Crocker Fan of Sabah,Northern Borneo.Our results,coupled with previous data,show that the Crocker Fan sediments in Sabah of Northern Borneo display similar age spectra to the Rajang Fan sediments in Sarawak of Central Borneo,with two major age clusters at 130-80 and 280-200 Ma.Further provenance analysis based on mineral shape with a prismatic characteristic and similar detrital zircon Hf isotopes of the two formations illustrates that the Jurassic-Cretaceous and partly Triassic detrital zircons of the Crocker and Rajang Fan sediments were derived from the erosion of contemporaneous magmatic rocks;part of Permian-Triassic ones could be the recycling of the Jurassic deposits in SW Borneo.The initial provenance of these Permian-Triassic detritus could be synchronous magmatic rocks in the Tin belt of the Malay Peninsula.Combining with previous data,we propose that the entire Borneo continent,including both Southern and Northern Borneo,developed a common Mesozoic continental magmatic arc.Moreover,we postulate that the Rajang and Crocker fans formed in a fore-arc extensional rift basin related to the retreat of the subducted Paleo-Pacific Plate beneath the Northern Borneo margin.
基金supported by the National Natural Science Foundation of China(Nos.42003014,42363004,42073051,42303023)Jiangxi Provincial Natural Science Foundation(No.20232BAB213070)the Natural Science Foundation of Shandong Province(No.ZR2022QD050)。
文摘Sulfur isotopes of S-bearing materials are powerful tools to trace various geological processes and sulfur sources in earth sciences,especially in ore deposits where sulfide-sulfate pair coprecipitates widely.However,in-situ S isotope determination of barite is challenging without natural matrix-matched reference material.In this study,we present two natural barite reference materials(1-YS and 294-YS)for in-situ sulfur isotopic analysis.Independent LA-MC-ICP-MS laboratories were utilized to test theδ34S micron-scale homogeneity of 1-YS and 294-YS barites that have 2s repeatabilities of better than±0.45‰and±0.41‰,respectively.Meanwhile,the in-situ analysis results are consistent with the results of the bulk analysis by GS-IRMS within uncertainty.The grand meanδ~(34)S values of 1-YS(13.37‰±0.42‰,2s)and 294-YS(14.38‰±0.44‰,2s)are the final recommended values obtained from four independent laboratories.All the results confirm the suitability of 1-YS and 294-YS barite used as calibration materials with respect to in-situ S isotopic analysis.Moreover,the new developed barite reference materials were used as matrix-matched standard to calibrate the barite samples from the Huayangchuan carbonatite-hosted U-polymetallic deposit(Qinling orogenic belt,western China)to obtainδ34S values.Utilizing the temperaturedependentδ34S fractionation of barite-pyrite pair,we calculate the formation temperature of barite(i.e.,506 to 537°C)and theδ34S value of mineralizing fluid(i.e.,-7.11‰to-7.59‰)in the Huayangchuan deposit.The results indicate an involvement of sedimentary sulfur,presumably acting as a potential uranium source(e.g.,upper crustal materials)for the giant Huayangchuan deposit.
基金supported by National Natural Science Foundation of China(42473009).
文摘Stable Sr isotopic composition(δ^(88/86)Sr)can be used to study magmatic processes,but their fractionation mechanism during magmatic evolution remains unclear.To understand the fractionation behaviors of the stable Sr isotopes during magmatism,we report theδ^(88/86)Sr values of the Huili granitic pluton,which was subjected to intensive crystal-melt separation.The Huili pluton consists of K-feldspar granite and more evolved albite granite,and the albite granite exhibits significantly higherδ^(88/86)Sr values(+0.36‰to+0.52‰)than that of K-feldspar granite(+0.11‰to+0.25‰).K-feldspar,which contributes most of the Sr budget of the K-feldspar granite,has slightly lowerδ^(88/86)Sr values(−0.01‰to+0.17‰)than the whole rock.Theδ^(88/86)Sr variation of the Huili granites can be explained by separation of melt from K-feldspar-dominated crystals,because crystallization of K-feldspar can result in heavy Sr isotopic composition of the extracted interstitial melt.Stable Sr and Ba isotopic ratios in the Huili granites are highly coupled toward the heavy direction,refl ecting their similar element partitioning and isotope fractionation behaviors between the crystalline K-feldspar and melt.This study indicates that melt extraction plays a key role in granitic magma evolution.
基金Under the auspices of the National Science Foundation for Distinguished Young Scholars(No.42425107)the Science and Technology Project of Gansu Province(No.24JRRA168,23ZDKA017)+1 种基金the Key Talent Project in Gansu Province(No.2025RCXM057)National Nature Science Foundation of China(No.42107063)。
文摘In this study,we systematically explored the environmental significance of stable isotope characteristics and the controlling factors of precipitation stable isotopes in the source region of the Three Rivers(SRTR),the transitional zone of the Qinghai-Tibet Plateau in China.A total of 862 precipitation samples were collected from six fixed-point sampling locations between 2019 and 2021 in the SRTR.In June,the values of hydrogen(δD)and oxygen(δ^(18)O)stable isotopes were most enriched.The deuterium-excess(d-excess)in atmospheric precipitation was>0 in the SRTR;however,the maximum value of d-excess occurred in October.Moreover,the slopes of the local meteoric water line(LMWL)for Dari,Zaduo,Maduo,Qumalai,and Tuotuohe sites were lower than those of the global met-eoric water line(GMWL).In contrast,the slope of the LMWL for Zhimenda was higher than that of the GMWL.The altitude effects of oxygen(δ^(18)O)and hydrogen(δD)isotopes of precipitation were 0.70‰/100 m and 5.22‰/100 m,respectively.When the temperature was≤5℃,there was a significant temperature effect on stable oxygen isotope of precipitation(0.24‰/℃,P<0.05).Furthermore,even a minor increase(1%)in the weight of raindrops after falling results in a 0.82%rise in the evaporation enrichment rate ofδ^(18)O.Success-ive precipitation events also had a substantial influence on precipitation in the transitional region of the Qinghai-Tibet Plateau.The res-ults of this study provide a theoretical basis for revealing the impact mechanism of precipitation in the transitional zone of the Qinghai-Tibet Plateau under a warming climate.
基金Supported by the National Natural Science Foundation of China(Nos.42322302,42373048)the Youth Innovation Promotion Association,Chinese Academy of Sciences(No.2022207)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42020303)the Laoshan Laboratory(No.LSKJ202204100)。
文摘Marine carbonates,the major carrier of carbon upon the upper crust,can be subducted into the Earth’s interior along with oceanic crust,and then returned to the surface through magmatism,which constitute the deep carbon cycle.This process plays an important role in modulating the CO_(2) concentrations in the atmosphere over geologic time,and thus the forming of the habitable earth.Therefore,identifying recycled marine carbonates in the mantle is critical to well understand the global deep carbon cycle.Calcium is one of the major constituent cations in marine carbonates and its isotopes may be a potential tracer for recycled marine carbonates in the mantle.To further evaluate the capability and challenges of Ca isotopes as such a geochemical tracer,we reviewed the Ca isotopic compositions in important reservoirs and the behavior of Ca isotopes during high-temperature geological processes that are related to the deep carbon cycle,including plate subduction,mantle metasomatism,mantle partial melting,magma differentiation,etc.Available studies show that carbonate-rich marine sediments have significantly lowerδ^(44/40) Ca than the Earth mantle,and metasomatism by such recycled materials can cause lighter Ca isotopic compositions in deep mantle-derived rocks than those of the depleted mantle and mid ocean ridge basalts.However,the Ca isotopic fractionation during partial melting of mantle peridotites is small(~0.10‰)and the Ca isotopic fractionation during plate subduction and intermediate-mafic magma evolution is indistinguishable.These investigations suggest that Ca isotopes have great advances in tracing such recycled materials in the mantle.However,other processes(such as the influence by partial melts of eclogites)may induce similar effects on mantle-derived rocks as subducted marine carbonates but still remains debated,and thus further investigations are strongly needed in the future.
基金supported by the National Natural Science Foundation of China(No.42372192)Shanxi Province science and technology plan joint unveiling project(No.20201101002)。
文摘The methane adsorption capacity,gas content,and carbon isotope characteristics of coal are crucial parameters that determine the productivity of coalbed methane(CBM)wells and their development potential.In this paper,test analyses of methane adsorption,gas content and carbon isotope of methane were carried out using 89 samples from the No.3 coal seam in the southwestern part of the Qinshui Basin.Their characteristics and correlations were analyzed.A relationship model between methane adsorption,gas content,carbon isotopes,coal metamorphism and material composition were established,and its controlling mechanism was investigated.The results indicate that the distribution patterns of Langmuir volume and Langmuir pressure in No.3 coal seam are mainly determined by the material composition and the thermal evolution level.The methane gas content in coal is mainly affected by the burial depth,microcosmic co mposition,mineral conte nt,moisture content and ash yield,adsorption capacity and metamorphism of the coal.The methane carbon isotope(δ^(13)C_(1))values in the natural desorbed gas from No.3 coal seam range from-26.95%to-57.80‰,with a mean value of-34.53‰.δ^(13)C_(1)in coal shows a two-stage variation pattern with increasing in vitrinite reflectance(R_(max)^(o)).When R_(max)^(o)is blow 3.0%,δ^(13)C_(1)values of methane in coal become progressively heavier with increasing R_(max)^(o).When R_(max)^(o)reaches or exceeds 3.0%,δ^(13)C_(1)values exhibit a lightning trend with furth er increases in R_(max)^(o),which is primarily controlled by the carbon isotope fractionation effects during thermal evolution.
基金supported by the National Natural Science Foundation of China(No.42025705)the Construction Project of Modern Agricultural Science and Technology Innovation Alliance of Guangdong Province,China(No.2023KJ112)+1 种基金the National Natural Science Foundation of China(Nos.41977291 and 42177242)the GDAS’Project of Science and Technology Development,China(No.2019GDASYL-0103048).
文摘Coal power plants annually generate quantities of byproducts that release environmentally hazardous heavy metals like Cd and Pb.Understanding the behavior and spatiotemporal impacts on soils of these releases is crucial for pollution control.This study investigated the concentrations and isotope ratios of Cd/Pb in combustion byproducts,depositions and soils collected froma coal-fired power plant or its surrounding area.The pulverized fuel ash(PFA)and desulfurized gypsum(DG)exhibited heavier Cd isotopes withΔ^(114)Cd values of 0.304‰and 0.269‰,respectively,while bottom ash(BA)showed lighter Cd isotopes(Δ^(114)CdBA-coal=–0.078‰),compared to feed coal.We proposed a two-stage condensation process that governs the distribution of Cd/Pb,including accumulation on PFA and DG within electrostatic precipitators and desulfurization unit,as well as condensation onto fine particles upon release from the stack.Emissions from combustion and large-scale transport make a significant contribution to deposition,while the dispersion of Cd/Pb in deposition is primarily influenced by the prevailing wind patterns.However,the distribution of Cd/Pb in soils not only exhibit predominant wind control but is also potentially influenced by the resuspension of long-term storage byproducts.The power plant significantly contributes to soil in the NW–N–NE directions,even at a considerable distance(66%–79%),demonstrating its pervasive impact on remote regions along these orientations.Additionally,based on the vertical behavior in the profile,we have identified that Cd tends to migrate downward through leaching,while variations in Pb respond to the historical progression of dust removal.
基金sponsored by the National Natural Science Foundation of China(No.12305190)Lingchuang Research Project of China National Nuclear Corporation(CNNC).
文摘Medical isotopes are the foundation material for nuclear medicine and are primarily produced through in-reactor irradia-tion.Neutron spectrum regulation is the main technical approach for enhancing the production of medical isotopes,and it requires determining the optimal neutron spectrum and quantifying the values of neutrons in different energy regions.We calculated the neutron energy region values for 20 medical isotopes(^(14)C,^(32)P,^(47)Sc,^(60)Co,^(64)Cu,^(67)Cu,^(89)Sr,^(90)Y,^(99)Mo,^(125)I,^(131)I,^(153)Sm,^(161)Tb,^(166)Ho,^(177)Lu,^(186)Re,^(188)Re,^(92)Ir,^(225)Ac,and ^(252)Cf).The entire energy range was divided into 238 energy regions to improve the energy spectrum resolution,and both fast and thermal reactors were simulated to enhance universal applicability.A dataset of neutron energy region values across the entire energy range was built,which identifies the positive and negative-energy regions and guides the neutron spectrum regulation process during in-reactor medical isotope produc-tion.We conducted neutron spectrum regulation based on this dataset,which effectively improved the production efficiency of medical isotopes and demonstrated the correctness and feasibility of the dataset.
基金ISRO-RESPOND GAP3332 and PMN-MOES GAP2175 Project support this work.
文摘Extraterrestrial dust exhibits a wide range of textural,chemical and oxygen isotopic compositions due to the heterogeneity of their precursors and modification during atmospheric entry.Experimental heating provides an opportunity to investigate the relationship between thermal processing and micrometeorite composition for a known precursor material.We conducted experiments to simulate the atmospheric entry of micrometeorites(MMs)using controlled,short-duration(10-50 s)flash heating(400-1600℃)of CI chondrite chips(<1500µm)in atmospheric air(1 bar,21%O2)combined with microanalysis(textures,chemical and isotopic compositions)of the experimental products.The heated chips closely resemble natural samples,with materials similar to unmelted MMs,partially melted(scoriaceous)MMs and fully melted cosmic spherules produced.We reproduced several key features such as dehydration cracks,magnetite rims,volatile gas release,vesicle formation and coalescence,melting and quench cooling.Our parameter space allows for discriminating peak temperature and heating duration effects.Peak temperature is the first-order control on MM mineralogy,while heating duration controls vesicle coalescence and homogenization.When compared against previous heating experiments,our data demonstrates that CI chondrite dust is more thermally resistant,relative to CM chondrite dust,by approximately+200℃.The 207 measurement of O-isotopes allows,for the first time,petrographic effects(such as volatile degassing and melting)to be correlated against bulk O-isotope evolution.Our results demonstrate findings applicable to CI chondrites and potentially to all fine-grained hydrated carbonaceous chondrite dust grains:(1)O-isotope variations arising during sub-solidus heating are dominated by the release of water from phyllosilicates,forcing the residual MM composition towards its anhydrous precursor composition.(2)Oxygen isotope compositions undergo the most significant changes at supra-solidus temperatures.As previously demonstrated and now empirically confirmed,most of these changes are driven by a mass-dependent fractionation effect caused by evaporation,which shifts residual rock compositions toward heavier values.Mixing with atmospheric air alters compositions toward the terrestrial fractionation line.Notably,these two processes do not begin simultaneously.Our data indicate that at 1200℃,isotopic evolution is dominated by evaporative mass loss.However,at higher temperatures(1400-1600℃),both pronounced evaporation and mixing with atmospheric oxygen become active,resulting in a more complex isotopic signature.(3)The total change in Δ17O during heating up to 1600℃is<3‰and in most scenarios<2‰.
基金supported by the National Natural Science Foundation of China(U21A2033)the Fundamental Research Funds for the Central Universities(2652022103).
文摘Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not yet fully understood.In this study,the V(V)reduction mechanisms with concomitant V isotope fractionation by the Gram-positive bacterium Bacillus subtilis(B.subtilis)and the Gramnegative bacterium Thauera humireducens(T.humireducens)were investigated.Both strains could effectively reduce V(V),removing(90.5%±1.6%)and(93.0%±1.8%)of V(V)respectively from an initial concentration of 50 mg L^(-1) during a 10-day incubation period.V(V)was bioreduced to insoluble vanadium(IV),which was distributed both inside and outside the cells.Electron transfer via cytochrome C,nicotinamide adenine dinucleotide,and glutathione played critical roles in V(V)reduction.Metabolomic analysis showed that differentially enriched metabolites(quinone,biotin,and riboflavin)mediated electron transfer in both strains.The aqueous V in the remaining solution became isotopically heavier as V(V)bioreduction proceeded.The obtained V isotope composition dynamics followed a Rayleigh fractionation model,and the isotope enrichment factor(e)was(–0.54‰±0.04‰)for B.subtilis and(–0.32‰±0.03‰)for T.humireducens,with an insignificant difference.This study provides molecular insights into electron transfer for V(V)bioreduction and reveals V isotope fractionation during this bioprocess,which is helpful for understanding V biogeochemistry and developing novel strategies for V remediation.
基金Youth Fund of National Natural Science Foundation of China(42302170)CNPC Scientific and Technological Innovation Fund(2022DQ02-0104)RIPED Open Project Fund(2024-KFKT-31).
文摘Taking deep coal-rock gas in the Yulin and Daning-Jixian areas of the Ordos Basin,NW China,as the research object,full-diameter coal rock samples with different cleat/fracture development degrees from the Carboniferous Benxi Formation were selected to conduct physical simulation and isotope monitoring experiments of the full-life-cycle depletion development of coal-rock gas.Based on the experimental results,a dual-medium carbon isotope fractionation(CIF)model coupling cleats/fractures and matrix pores was constructed,and an evaluation method for free gas production patterns was established to elucidate the carbon isotope fractionation mechanism and adsorbed/free gas production characteristics during deep coal-rock gas development.The results show that the deep coal-rock gas development process exhibits a three-stage carbon isotope fractionation pattern:“Stable(Ⅰ)→Decrease(Ⅱ)→Increase(Ⅲ)”.A rapid decline in boundary pressure in stageⅢleads to fluctuations in isotope value,characterized by a“rapid decrease followed by continued increase”,with free gas being produced first and long-term supply of adsorbed gas.The CIF model can effectively match measured gas pressure,cumulative gas production,and δ^(13)C_(1) value of produced gas.During the first two stages of isotope fractionation,free gas dominated cumulative production.During the mid-late stages of slow depletion production,the staged pressure control development method can effectively increase the gas recovery.The production of adsorbed gas is primarily controlled by the rock's adsorption capacity and the presence of secondary flow channels.Effectively enhancing the recovery of adsorbed gas during the late stage remains crucial for maintaining stable production and improving the ultimate recovery factor of deep coal-rock gas.
基金supported by the National MCF Energy Research and Development Program(Grant Nos.2024YFE03190001,2024YFE03190004,2022YFE03030001,and 2019YFE03030002)the National Natural Science Foundation of China(Grant Nos.12405257,12475215,and 12475219)+2 种基金the Natural Science Foundation of Sichuan Province,China(Grant Nos.2023NSFSC1289 and 2025ZNSFSC0066)the Nuclear Technology Research and Development Program(Grant No.HJSYF2024(02))the Innovation Program of Southwestern Institute of Physics(Grant No.202301XWCX001)。
文摘The isotope effect on zonal flows(ZFs)and turbulence remains a key issue that is not completely solved in fusion plasmas.This paper presents the first experimental results of the ab initio prediction of causal relation between geodesic acoustic mode(GAM)and ambient turbulence at different isotope masses in the edge of HL-2A tokamak,where transfer entropy method based on information-theoretical approach is utilized as a quantified indicator of causality.Analysis shows that GAM is more pronounced in deuterium plasmas than in hydrogen,leading to a lower heat transport as well as more peaked profiles in the former situation.The causal impact of GAM on conductive heat flux component is stronger than on the convective component,which is resulted from a larger causal influence of zonal flow on temperature fluctuation.While a stronger GAM in deuterium plasmas has larger influence on all flux components,the relative change in temperature fluctuation and coefficient is more obvious when the ion mass varies.These findings not only offer an in-depth understanding of the real causality between zonal flow and turbulence in the present isotope experiments,but also provide useful ways for the physical understandings of transport and zonal flow dynamics in future deuterium-tritium fusion plasmas.
