Based on geochemical data from natural gas samples across spring water systems and sedimentary basins,including Songliao,Bohai Bay,Sanshui,Sichuan,Ordos,Tarim and Ying-Qiong,this paper systematically compares the geoc...Based on geochemical data from natural gas samples across spring water systems and sedimentary basins,including Songliao,Bohai Bay,Sanshui,Sichuan,Ordos,Tarim and Ying-Qiong,this paper systematically compares the geochemical compositions of abiogenic versus biogenic gases.Emphasis is placed on the diagnostic signatures of abiogenic gases in terms of gas composition,and carbon,hydrogen and helium isotopes.The main findings are as follows.(1)In hydrothermal spring systems,abiogenic alkane gases are extremely scarce.Methane concentrations are typically less than 1%,with almost no detectable C^(2+)hydrocarbons.The gas is dominantly composed of CO_(2),while N_(2)is the major component in a few samples.(2)Abiogenic alkane gases display distinct isotopic signatures,including enriched methane carbon isotopic compositions(δ^(13)C_(1)>-25‰generally),complete carbon isotopic reversal(δ^(13)C_(1)>δ^(13)C_(2)>δ^(13)C_(3)>δ^(13)C_(4)),and enriched helium isotope(R/Ra>0.5,CH_(4)/^(3)He≤10^(6)generally).(3)The hydrogen isotopic composition of abiogenic alkane gases may be characterized by a positive sequence(δD_(1)<δD_(2)<δD_(3)),or a complete reversal(δD_(1)>δD_(2)>δD_(3)),or a V-shaped distribution(δD_(1)>δD_(2),δD_(2)<δD_(3)).The hydrogen isotopic compositions of methane generally show limited variation(about 9‰),possibly due to hydrogen isotopic exchange with connate water.(4)In terms of identifying gas origin,CH_(4)/^(3)He-R/Ra andδ^(13)CCO_(2)-R/Ra charts are more effective than CO_(2)/^(3)He-R/Ra chart.These new geological insights provide theoretical clues and diagnostic charts for the genetic identification of natural gas and further research on abiogenic gases.展开更多
The growth trajectory of hailstones within clouds has remained elusive due to the inability to trace them directly,impeding the comprehension of their underlying growth mechanisms.This study investigated hailstone ver...The growth trajectory of hailstones within clouds has remained elusive due to the inability to trace them directly,impeding the comprehension of their underlying growth mechanisms.This study investigated hailstone vertical growth trajectories by detecting the stable isotope signatures(2H and 18O compositions)of different shells in 27 hailstones from 9hailstorms,which allowed us to capture the ambient temperature during hailstone growth.The vertical growth trajectories were obtained by comparing the isotopic compositions of water condensate in clouds,derived from the Adiabatic Model,with those measured in hailstones.Although hailstone growth was primarily observed in the–10°C to–30°C temperature layer,the embryo formation height and subsequent growth trajectories significantly varied among hailstones.Embryos formed over a wide range of temperatures(–8.7°C to–33.4°C);four originated at temperatures above–15°C and 16originated at temperatures below–20°C,suggesting ice nuclei composed of bioproteins and mineral dust,respectively.Among the 27 measured hailstones,3 exhibited minimal vertical movement,16 exhibited a monotonic rise or fall,and the remaining 8 exhibited alternating up-down trajectories;only one experienced“recycling”during up-down drifting.Trajectory analysis revealed that similar-sized hailstones from a single storm tended to form at similar heights,whereas those larger than 25 mm in diameter exhibited at least one period of upward growth.Vertical trajectories derived from isotopic analysis were corroborated by radar hydrometeor observations.展开更多
0 INTRODUCTION Uraninite and pitchblende are the most important ore minerals in nearly all types of uranium deposits.Therefore,the U-Pb isotopic system of uraninite and pitchblende are widely used in dating uranium de...0 INTRODUCTION Uraninite and pitchblende are the most important ore minerals in nearly all types of uranium deposits.Therefore,the U-Pb isotopic system of uraninite and pitchblende are widely used in dating uranium deposits.展开更多
The two-body fragmentation dynamics of water isotopologues dications(H_(2)O^(2+),HOD^(2+),and D_(2)O^(2+))induced by200 eV electron impact is investigated.Two fragment ions and an emitted electron are detected in coin...The two-body fragmentation dynamics of water isotopologues dications(H_(2)O^(2+),HOD^(2+),and D_(2)O^(2+))induced by200 eV electron impact is investigated.Two fragment ions and an emitted electron are detected in coincidence,and their momentum vectors are determined by employing a reaction microscope.The complete kinematical information of four two-body fragmentation channels of H^(+)+OH+,H^(+)+OD^(+),D^(+)+OH^(+),and D^(+)+OD+is obtained.By analyzing the projectile energy-loss spectrum,the initial electronic state of the two-body dissociation channel is determined.Upon examining the kinetic energy release(KER)distributions of the four fragmentation channels,a clear difference is found between the two-body fragmentation channel H^(+)+OD+and the other three channels.The isotopic effect in the two-body fragmentation is demonstrated by the analysis of the relative yields of the two-body fragmentation channels originating from different isotopologues,which shows preferential cleavage of the O-H bond over the O-D bond.These results provide deeper insight into the microscopic dynamic mechanisms in water radiolysis.展开更多
Biomarker and stable carbon isotope analyses are presented for the Garau Formation of the Cretaceous Age,an important source rock in western Iran,to reveal its potential as an oilprone source rock.The C_(28)/C_(29)ste...Biomarker and stable carbon isotope analyses are presented for the Garau Formation of the Cretaceous Age,an important source rock in western Iran,to reveal its potential as an oilprone source rock.The C_(28)/C_(29)sterane ratio value range(0.72 to 0.83)of bitumen samples from the formation suggests that they were likely formed during phytoplankton blooms.Sterane,hopane,and isoprenoid/n-alkane ratios indicate that the formation's organic matter predominantly consists of algae,and bacteria,accompanied by some reworked material derived from higher plants.Due to the predominance of anoxic conditions and the actions of sulfate-reducing bacteria,the bitumen present is enriched with sulfur compounds.The percentages of saturates,aromatics,and nitrogen-sulfuroxygen(NSO)fractions in the bitumen samples classify them as naphthenic oils.Isotope analysis reveals that biodegradation and water-washing have reduced the concentrations of some volatile saturates and low molecular weight aromatics in the bitumen samples.These actions have resulted in distinctiveδ^(13)C values for the formation's kerogen and bitumen fractions.The formation's organic matter has been subjected to high-temperature thermal regimes and has entered the oil-generation window at the sampled localities,with vitrinite reflectance(%R_(C))varying between 0.7%and 0.75%.展开更多
The Gejiu tin-copper-(tungsten)(Sn-Cu-(W))polymetallic district is located in the southwest of the W-Sn metallogenic belt in the western Youjiang Basin,Yunnan,Southwest China.Abundant W minerals have been identified i...The Gejiu tin-copper-(tungsten)(Sn-Cu-(W))polymetallic district is located in the southwest of the W-Sn metallogenic belt in the western Youjiang Basin,Yunnan,Southwest China.Abundant W minerals have been identified in the region via exploration.However,metallogenic sources and evolution of W remain unclear,and the existing metallogenic model has to be updated to guide further ore prospecting.Elemental and Sr-Nd isotopic data for scheelites assist in the determination of sources and evolution of the W-mineralizing fluids and metals in the district.Based on field geological survey,the scheelites in the Gejiu district can be categorized into three types:altered granite(Type Ⅰ),quartz vein(Type Ⅱ)from the Laochang deposit,and skarn(Type Ⅲ)from the Kafang deposit.Types Ⅰ and Ⅱ scheelites have low molybdenum(Mo)and strontium(Sr)contents,and Type Ⅱ scheelite has lower Sr contents than Type Ⅰ as well as higher Mo and Sr contents than Type Ⅲ scheelites.Varying Mo contents across the scheelite types suggests that the oxygen fugacity varied during ore accumulation.Type Ⅰ and Type Ⅱ scheelites exhibit similar rare earth elements(REE)patterns;Type Ⅲ scheelite contains lower REE content,particularly HREE,compared with the other scheelites.All scheelites exhibit negative Eu anomalies in the chondrite-normalized REE patterns.As the W-mineralization and two-mica granite share close spatial and temporal relationships,the negative Eu anomalies were likely inherited from the two-mica granite.Type Ⅰ and Type Ⅱ scheelites display varied(^(87)Sr/^(86)Sr)_(82 Ma)(0.7090-0.7141)andε_(Nd)(82 Ma)(from−9.9 to−5.4)values,similar to those of granite.However,Type Ⅲ scheelite exhibits lower(^(87)Sr/^(86)Sr)_(82 Ma)(0.7083-0.7087)and lowerε_(Nd)(82 Ma)(from−10.5 to−6.9)values than the two-mica granite.This indicates that the two-mica granite alone did not provide the ore-forming fluids and metals and that the Type Ⅲ scheelite ore-forming fluids likely involved external fluids that were probably derived from carbonate rocks.The implication is that highly differentiated two-mica granites were the source of primary W-bearing metals and fluids,which is consistent with earlier research on the origin of Sn ore-forming materials.展开更多
The widespread dolomite of the Sinian Dengying Formation in the Sichuan Basin(China)serves as one of the most important oil and gas reservoir rocks of the basin.Well WT1,as an exploration well,is recently drilled in t...The widespread dolomite of the Sinian Dengying Formation in the Sichuan Basin(China)serves as one of the most important oil and gas reservoir rocks of the basin.Well WT1,as an exploration well,is recently drilled in the Kaijiang County,northeastern Sichuan Basin(SW China),and it drills through the Dengying Formation dolomite at the depth interval of 7500–7580 m.In this study,samples are systematically collected from the cores of that interval,followed by new analyses of carbon-oxygen isotope,major elements,trace elements,rare earth elements(REEs)and EP-MA.The Dengying Formation dolomites of Well WT1 haveδ13C values of 0.37‰to 2.91‰andδ18O values of-5.72‰to-2.73‰,indicating that the dolomitization fluid is derived from contemporary seawater in the near-surface environment,rather than the burial environment.Based on the REE patterns of EPMA-based in-situ data,we recognized the seawater-sourced components,the mixedsourced components and the terrigenous-sourced components,indicating the marine origin of the dolomite with detrital contamination and diagenetic alteration.Moreover,high Al,Th,and Zr contents indicate significant detrital contamination derived from clay and quartz minerals,and high Sr/Ba and Sr/Cu ratios imply a relatively dry depositional environment with extremely high seawater salinity,intensive evaporation,and strong influences of terrigenous sediment.展开更多
The End-Permian mass extinction(EPME),Earth’s most severe biocrisis,occurred proximal to the Permian-Triassic Boundary(PTB),with marine ecosystems experiencing catastrophic collapse.This study employs stable carbon(...The End-Permian mass extinction(EPME),Earth’s most severe biocrisis,occurred proximal to the Permian-Triassic Boundary(PTB),with marine ecosystems experiencing catastrophic collapse.This study employs stable carbon(δ^(13)C)and oxygen isotopes from marine carbonates in the Haidai Section(Xuanwei,northeastern Yunnan)to decipher paleoenvironmental drivers.The well-preserved stratigraphic sequence encompasses the Upper Permian(Yangxin and Xuanwei Formations)transitioning into the Lower Triassic(Feixianguan and Jialingjiang Formations),providing a continuous marine sedimentary archive.A marked negativeδ^(13)C excursion(-9.66‰V-PDB)occurs at the PTB,initiating from+0.82‰with subsequent gradual recovery.This geochemical signature correlates with:90%reduction in primary productivity Biodiversity collapse exhibiting cluster extinction patterns Prolonged suppression of ecological recovery Concurrently,reconstructed seawater temperatures reveal extreme thermal fluctuations,surging from 23℃to 32℃at the PTB before precipitously declining to 16℃.These perturbations demonstrate coupled biogeochemical dynamics wherein:•Carbon cycle destabilization disrupted nutrient fluxes.•Temperature oscillations exceeded marine taxa thermal tolerances.•Synergistic environmental stresses amplified extinction selectivity.Theδ^(13)C-temperature covariance(r^(2)=0.085)establishes mechanistic linkages between physicochemical perturbations and biotic responses.Our findings demonstrate that the EPME was driven by positive feedback loops in which:Volcanic CO₂emissions triggered carbonate saturation decline Thermal stratification exacerbated anoxia Biogeochemical cycling perturbations suppressed primary producers This integrated geochemical record from the Haidai Section provides critical insights into environment-organism coevolution during Phanerozoic Earth’s most profound mass extinction.展开更多
To investigate the stable chromium(Cr)isotope variations during melt percolation in the mantle,we ana-lyzed the Cr isotopic compositions of fresh ultramafic rocks from the Balmuccia and Baldissero peridotite massifs l...To investigate the stable chromium(Cr)isotope variations during melt percolation in the mantle,we ana-lyzed the Cr isotopic compositions of fresh ultramafic rocks from the Balmuccia and Baldissero peridotite massifs located in the Italian Alps.These massifs represent fragments of the subcontinental lithospheric mantle.The samples collected included lherzolites,harzburgites,dunites,and pyroxenites.Lherzolites,formed through 5%-15%fractional melting of a primitive mantle source,exhibited δ^(53)Crvalues ranging from−0.13‰±0.03‰to−0.03‰±0.03‰.These values correlated negatively with Al_(2)O_(3)content,sug-gesting that partial melting induces Cr isotopic fractionation between the melts and residual peridotites.Harzburgites and dunites,influenced by the silicate melt percolation,displayed distinctδ^(53)Cr values.Notably,dunites not spatially associated with the pyroxenite veins exhibited slightly elevatedδ^(53)Cr val-ues(−0.05‰±0.03‰to 0.10‰±0.03‰)relative to lherzolites.This difference likely resulted from pyroxene dissolution and olivine precipitation during melt percolation processes.However,one dunite sample in direct contact with pyroxenite veins showed lowerδ^(53)Cr values(−0.26‰±0.03‰),possibly owing to the kinetic effects during silicate melt percolation.Pyroxenites are formed through the interac-tion of basaltic melts with the surrounding peridotite via a metasomatic reaction or crystallization in a vein.Most of theirδ^(53)Cr values(−0.26‰±0.03‰to−0.13‰±0.03‰)are positively correlated with MgO contents,suggesting that they were influenced by magmatic differentiation.However,two subsam-ples from a single clinopyroxenite vein exhibit anomalously lowδ^(53)Crvalues(−0.30‰±0.03‰and−0.43‰±0.03‰),which are attributed to kinetic isotopic fractionation during melt-percolation pro-cesses.Our findings suggest that melt percolation processes in the mantle contribute to the Cr isotopic heterogeneity observed within the Earth’s mantle.展开更多
The Xingyuan large fluorite deposit in Fengning,Hebei Province,China,is a significant deposit in the North Hebei-West Liaoning fluorite mineralization belt.The ore bodies are structurally controlled and occur in fault...The Xingyuan large fluorite deposit in Fengning,Hebei Province,China,is a significant deposit in the North Hebei-West Liaoning fluorite mineralization belt.The ore bodies are structurally controlled and occur in fault zones near granitic porphyry veins.Previous studies have focused on the geology and ore-controlling factors,whereas the general features of the hydrothermal systems that contributed to the formation of the deposit remain unclear.This study investigated the nature,origin,and evolution of mineralizing fluids in the Fengning deposit,based on fluid inclusion and H-O isotope data.The fluid inclusions in fluorite are mostly H2O-rich,gas-liquid,two-phase inclusions,along with a few three-phase inclusions containing halite daughter crystals and CO_(2)gas.The ore-forming fluid was variable in homogenization temperature(108-388°C),salinity(0.2-47.4 wt%NaCl equivalent),and density(0.58-1.11 g/cm^(3)),which indicate it was a H2O-NaCl-CO_(2)system of moderate-low temperature,low salinity,and low density.Fluorite H-O isotopes(δD_(V-SMOW)=−123.5‰to−111.8‰;δ^(18)O_(V-SMOW)=−10.3‰to−6.5‰),temperature data,and fluid compositions indicate the mineralizing fluid was initially dominated by magmatic waters,but then experienced a large influx of meteoric waters.The fluid temperature and salinity decreased and the density increased from the early to late stages of mineralization.The main mechanisms of fluorite precipitation were water-rock reactions and fluid cooling.The Xingyuan fluorite deposit is a post-magmatic hydrothermal deposit.展开更多
The Guanfang large-scale W deposit is located in the W polymetallic ore concentration area of Bozhushan in southeastern Yunnan,China.Despite extensive research,the fluid evolution process of the deposit remains ambigu...The Guanfang large-scale W deposit is located in the W polymetallic ore concentration area of Bozhushan in southeastern Yunnan,China.Despite extensive research,the fluid evolution process of the deposit remains ambiguous,leading to controversy regarding its genesis.This study conducted a detailed field geological survey,with systematic sampling of the KT6 orebody,to delineate mineralization stages.Fine mineralogy work,including the use of CL images of scheelite,in-situ LA-ICP-MS trace elements,and Sr isotopes,was carried out on diff erent generations of scheelite formed in various stages.The findings identified the evolution of fluids in the mineralization process,shedding light on the genesis of the deposit.The study revealed four mineralization stages at the Guanfang W deposit:prograde skarn stage,retrograde skarn stage,quartz-sulfide stage,and carbonate-fluorite stage.Diff erent generations of scheelite(Sch I,Sch II,Sch III)were observed in the first three stages,displaying distinct chondrite-normalized REE patterns.The REE of Sch I mainly substituted into the Ca site by REE^(3+)+□_(Ca),and there may be a similar substitution of Nb for REE,whereas it is not the main substitution method.The REE of Sch II mainly enter the scheelite lattice in the form of REE 3++Na+,and there may be a substitution of Nb for REE isomorphism.In the early stage,The REE of Sch III was mainly replaced by Nb for REE isomorphism,while in the later stage,the replacement mode of REE^(3+)+□_(Ca)coexisted with it.The Mo content in scheelite,along with the corresponding Eu anomalies in both scheelite and garnet,collectively imply that the ore-forming fluids during various mineralization stages were predominantly oxidizing,with only slight reducibility observed in Sch II.The in-situ Sr isotope ratios of scheelite concentrates ranged from 0.7093 to 0.7153,resembling those of the Bozhushan granite,indicating a relationship between W mineralization and granite.In addition,the Y/Ho ratios of scheelite from various mineralization stages exhibit a narrow range(19-31),with a pronounced correlation between the contents of Y and Ho and a similar trend in their variation.This consistency suggests that the Guanfang deposit has undergone a uniform or comparable evolutionary process,implying a stable ore-forming fluid across diff erent mineralization stages.展开更多
Exploration and development of large gas fields is an important way for a country to rapidly develop its natural gas industry.From 1991 to 2020,China discovered 68 new large gas fields,boosting its annual gas output t...Exploration and development of large gas fields is an important way for a country to rapidly develop its natural gas industry.From 1991 to 2020,China discovered 68 new large gas fields,boosting its annual gas output to 1925×108m3in 2020,making it the fourth largest gas-producing country in the world.Based on 1696 molecular components and carbon isotopic composition data of alkane gas in 70 large gas fields in China,the characteristics of carbon isotopic composition of alkane gas in large gas fields in China were obtained.The lightest and average values ofδ^(13)C_(1),δ13C2,δ13C3andδ13C4become heavier with increasing carbon number,while the heaviest values ofδ^(13)C_(1),δ13C2,δ13C3andδ13C4become lighter with increasing carbon number.Theδ^(13)C_(1)values of large gas fields in China range from-71.2‰to-11.4‰(specifically,from-71.2‰to-56.4‰for bacterial gas,from-54.4‰to-21.6‰for oil-related gas,from-49.3‰to-18.9‰for coal-derived gas,and from-35.6‰to-11.4‰for abiogenic gas).Based on these data,theδ^(13)C_(1)chart of large gas fields in China was plotted.Moreover,theδ^(13)C_(1)values of natural gas in China range from-107.1‰to-8.9‰,specifically,from-1071%o to-55.1‰for bacterial gas,from-54.4‰to-21.6‰for oil-related gas,from-49.3‰to-13.3‰for coal-derived gas,and from-36.2‰to-8.9‰for abiogenic gas.Based on these data,theδ^(13)C_(1)chart of natural gas in China was plotted.展开更多
Lack of information regarding lithium(Li)crystal chemistry in numerous minerals,especially those containing trace amounts of Li(ranging from a few to tens of ppm),limits our understanding of Li isotopic fractionation ...Lack of information regarding lithium(Li)crystal chemistry in numerous minerals,especially those containing trace amounts of Li(ranging from a few to tens of ppm),limits our understanding of Li isotopic fractionation in pegmatites.In this study,we examined the Li isotopic composition and Li content in various Li-poor(e.g.,quartz or feldspar)together with Li-rich(sopdumene or lepidolite)mineral phases within granitic pegmatites.We compiled a comprehensive dataset,encompassing a broad spectrum of Li contents(ranging from a few to tens of thousands of ppm)and Li isotopic values(-8‰to 41‰).The minerals exhibit distinct Li isotopic signatures.Specifically,elbaite and beryl show the highest values,while biotite displays a negative average.Compared to individual minerals,whole rocks demonstrate lower Li isotopic values,with pegmatites exhibiting the highest and non-granitic pegmatite wall rocks showing the lowest.Our study also uncovers a clear“V”shape relationship between Li isotopic values and logarithm of Li contents,with different mineral groups occupying specific regions within this shape.Furthermore,a significant correlation was observed between average Li isotopic values and Li-O(OH,F)bond lengths in various minerals.These discoveries underscore the crucial role of crystal chemistry in shaping the Li isotopic behavior in pegmatites from a statistical perspective.展开更多
1.Objective The Altay Orogenic Belt in Xinjiang,China is located in the west of the Central Asian Orogenic Belt and in the transition zone between the Siberian Plate and the Kazakhstan-Junggar Plate,extending approxim...1.Objective The Altay Orogenic Belt in Xinjiang,China is located in the west of the Central Asian Orogenic Belt and in the transition zone between the Siberian Plate and the Kazakhstan-Junggar Plate,extending approximately 500 km in northern Xinjiang,China(Fig.1a).The Altay Orogenic Belt has undergone two-way accretion of the Paleozoic crust and the Meso-Cenozoic intracontinental orogeny,leading to the formation of large numbers of intermediate-acid intrusions.More than 100000 pegmatite veins have been discovered in the intermediate-acid intrusions,and they constitute an important rare metal metallogenic belt of China(Fig.1b).展开更多
Recent advances in utilizing ^(17)O isotopic labeling methods for solid-state nuclear magnetic resonance(NMR)investigations of metal oxides for lithium-ion batteries have yielded extensive insights into their structur...Recent advances in utilizing ^(17)O isotopic labeling methods for solid-state nuclear magnetic resonance(NMR)investigations of metal oxides for lithium-ion batteries have yielded extensive insights into their structural and dynamic details.Herein,we commence with a brief introduction to recent research on lithium-ion battery oxide materials studied using ^(17)O solid-state NMR spectroscopy.Then we delve into a review of ^(17)O isotopic labeling methods for tagging oxygen sites in both the bulk and surfaces of metal oxides.At last,the unresolved problems and the future research directions for advancing the ^(17)O labeling technique are discussed.展开更多
Early Palaeozoic Cambrian A-type Kathalguri Granites in the Mikir Hills of northeastern (NE) India were studied to better understand the geodynamic settings in this region. This research presents new whole-rock geoche...Early Palaeozoic Cambrian A-type Kathalguri Granites in the Mikir Hills of northeastern (NE) India were studied to better understand the geodynamic settings in this region. This research presents new whole-rock geochemical and Sr, Nd, Pb isotopic data for the Cambrian granites in the Kathalguri Granite in Mikir Hills. The Kathalguri Granite shows geochemical characteristics of high SiO2, K2O and low FeOT, MgO, CaO, and P2O5 compositions. They belong to a high K Shoshonite to ultra-potassic series and display a weak metaluminous to peraluminous feature with A/CNK values of 0.83 to 1.02 with corundum and anorthite normative. FeOT/MgO varies from 2.93 - 7.49, is moderately oxidized and belongs to magnetite series. The rocks have a high ΣREE composition of 370.80 - 1353.23 ppm (average 568.55) and are enriched in LREE with flat HREE and (La/Yb)N values of 8.10 - 18.99, and display obvious strong negative Eu anomalies. Trace elements of the studied granites are characterized by enrichment in Rb, Th, U, Pb, Hf, and Sm, and depletion of Ba, Nb, Ta, and Sr. They display geochemical features of high Zr + Y + Nb + Ce values (241 - 934 ppm) and Ga/Al ratios 2.49 - 3.01 consistent with A-Type granites. Based on particular geochemical features, such as high Rb/Nb (3.10 - 19.53) and Low Y/Nb (0.09 - 2.28), Kathalguri Granite can be further classified as an A1-type subgroup. Granites display relatively low Sr (N ratio varying between 0.53 - 0.89 suggesting that the melts generated at greater depths (18 - 40 km), and fractionation at low pressures (−3 and total HGU 98.96 to 214.20. Kathalguri Granite dated by Rb-Sr isotopic isochrone as 489 ± 19 Ma with an initial 87Sr/86Sr 0.7199 ± 0.0017 and MSWD of 4.1, εSr(I) varied between 161.62 - 332.08 suggests that the Kathalguri Granite have originated from partial melting of ancient, evolved continental crustal material. The Sm-Nd Systematics has given a depleted mantle model (TDM) age ranging from 1733 - 2063 Ma with high negative εNd(t) values (−10.39 to −15.18) also hint at some heterogeneity or multiple source contributions in the melting process of the protolith. Xenoliths of older mafic rocks and Barapani arenites are seen within the Kathalguri Granite and are also supported by geochemical signatures of recycled crustal materials both mafic and sedimentary. It formed during the Cambrian reorganization of lithospheric plate motion related to the Pan-African-Braziliano event.展开更多
Lithium(Li),a crucial mineral resource for modern high-tech industries,is notably abundant in the northern Tibetan Plateau,primarily within lithium-rich salt lakes.However,the exploration and development of these reso...Lithium(Li),a crucial mineral resource for modern high-tech industries,is notably abundant in the northern Tibetan Plateau,primarily within lithium-rich salt lakes.However,the exploration and development of these resources are hindered due to an incomplete understanding of their nature and origin.Here we present results from a comprehensive study on the hydrochemical parameters,whole-rock geochemistry,H-O isotopes,and Li concentrations in surface brine,river water,geothermal springs,and associated rocks from two representative lithium-enriched salt lakes,the Laguo Co(LGC)and Cangmu Co(CMC)in Xizang to understand the genetic mechanisms.Our water-salt balance calculations and H-O isotopic analysis reveal that Li in LGC and CMC primarily originates from the Suomei Zangbo(SMZB,~91%)and Donglong Zangbo(DLZB,~75%)rivers,respectively.It is estimated that the LGC and CMC took a minimum of 6.0 ka and 3.0 ka to accumulate their current lithium resources,respectively.The distinct geological characteristics reflect evolutionary differences between the two lakes,suggesting diverse lithium sources and enrichment processes.The high lithium ion concentration and light lithium isotope composition in the SMZB river waters indicate the genetic relationship with lithium-enriched geothermal springs in the Tibetan Plateau.Our results suggest that lithium in the LGC originates from lithium-enriched geothermal springs and is primarily supplied through the small-scale SMZB river.In contrast,the formation and evolution of CMC are influenced by the northern Lunggar rifts,receiving a prolonged and stable input from the DLZB,resulting in high lithium concentrations and isotopic values.The absence of lithium-enriched geothermal springs and the prevalence of silicate rocks in the CMC catchment suggest that lithium may be sourced from the weathering of silicate rocks,such as granitic pegmatite veins containing lithium-rich beryl,widely distributed in the upstream area of DLZB.The forward modeling approach,quantifying the contribution fractions of different reservoirs(atmospheric precipitation,silicate,carbonate,and evaporite),indicates that the distinct lithium concentrations in the mainstream(>1 mg/L)and tributaries(<0.1 mg/L)are positively correlated with the ratio of silicate contributions to carbonate contributions,suggesting that dissolved lithium in river waters primarily originates from the weathering and dissolution of silicate rocks.The distinct sources and enrichment mechanisms of lithium in these two salt lakes are attributed to various evolutionary processes,topographical features,hydrological factors,fundamental geological settings,and tectonic histories,despite their spatial proximity.Furthermore,our study highlights the significant role of rivers in the formation of young salt lakes,in addition to geothermal springs.展开更多
Geothermal resources are increasingly gaining attention as a competitive,clean energy source to address the energy crisis and mitigate climate change.The Wugongshan area,situated in the southeast coast geothermal belt...Geothermal resources are increasingly gaining attention as a competitive,clean energy source to address the energy crisis and mitigate climate change.The Wugongshan area,situated in the southeast coast geothermal belt of China,is a typical geothermal anomaly and contains abundant medium-and low-temperature geothermal resources.This study employed hydrogeochemical and isotopic techniques to explore the cyclic evolution of geothermal water in the western Wugongshan region,encompassing the recharge origin,water-rock interaction mechanisms,and residence time.The results show that the geothermal water in the western region of Wugongshan is weakly alkaline,with low enthalpy and mineralization levels.The hydrochemistry of geothermal waters is dominated by Na-HCO_(3)and Na-SO_(4),while the hydrochemistry types of cold springs are all Na-HCO_(3).The hydrochemistry types of surface waters and rain waters are NaHCO_(3)or Ca-HCO_(3).The δD and δ^(18)O values reveal that the geothermal waters are recharged by atmospheric precipitation at an altitude between 550.0 and 1218.6 m.Molar ratios of maj or solutes and isotopic compositions of^(87)Sr/^(86)Sr underscore the significant role of silicate weathering,dissolution,and cation exchange in controlling geothermal water chemistry.Additionally,geothermal waters experienced varying degrees of mixing with cold water during their ascent.Theδ^(13)C values suggest that the primary sources of carbon in the geothermal waters were biogenic and organic.Theδ^(34)S value suggests that the sulfates in geothermal water originate from sulfide minerals in the surrounding rock.Age dating using 3H and^(14)C isotopes suggests that geothermal waters have a residence time exceeding 1 kaBP and undergo a long-distance cycling process.展开更多
Nitrogen deposition is an important means of exogenous nitrogen input in reservoir water.Agricultural activities around the reservoir lead to a sharp increase in the concentration of ammonia in the atmosphere,which po...Nitrogen deposition is an important means of exogenous nitrogen input in reservoir water.Agricultural activities around the reservoir lead to a sharp increase in the concentration of ammonia in the atmosphere,which poses a threat to the reservoir water body.Clarifying the contribution of agricultural ammonia release to atmospheric NH_(x)(gaseous NH_(3)and particulate NH_(4)^(+)),in the reservoir area can provide a theoretical foundation for local reactive nitrogen control.We collected atmospheric NH_(3)and NH_(4)^(+)samples during the agricultural periods and analyzed the isotopic characteristics of atmospheric NH_(x)and the contribution rates of different ammonia sources in the Xichuan area of the Danjiangkou Reservoir.The results showed that the initialδ~(15)N values of NH_(3)(-30.0‰to–7.2‰)and particulate NH_(4)^(+)(–33‰to+4.9‰for finer and coarser particles,respectively)are different,and their contribution ratios from dissimilar ammonia sources are also different,among which NH_(4)^(+)is more susceptible to meteorological factors.However,since the atmospheric NH_(x)in the Xichuan area is mainly gaseous NH_(3),the final sources of atmospheric ammonia nitrogen source depend on gaseous NH_(3).Agricultural sources(59%-74%)were the main NH_(3)sources in this area.Among them,the fertilizer use emission was dominant;it had the highest contribution rate in summer during the agricultural period and a more prominent impact in areas with less human interference.Reasonable regulation of the application of high-ammonia releasing fertilizer,especially during the agricultural period in summer,is an effective way to reduce the threat of atmospheric ammonia to water health.展开更多
The Nuri deposit is the only Cu-W-Mo polymetallic deposit with large-scale WO3 resources in the eastern section of the Gangdese metallogenic belt,Xizang,China.However,the genetic type of this deposit has been controve...The Nuri deposit is the only Cu-W-Mo polymetallic deposit with large-scale WO3 resources in the eastern section of the Gangdese metallogenic belt,Xizang,China.However,the genetic type of this deposit has been controversial since its discovery.Based on a study of the geological characteristics of the deposit,this study presents mineralization stages,focusing on the oxide stage and the quartz-sulfide stage where scheelite is mainly formed,referred to as Sch-A and Sch-B,respectively.Through LA-ICP-MS trace element and Sr isotope analyses,the origin,evolutionary process of the oreforming fluid and genesis of the ore deposit are investigated.Scanning Electron Microscope-Cathodoluminescence(SEMCL)observations reveal that Sch-A consists of three generations,with dark gray homogenous Sch-A1 being replaced by relatively lighter and homogeneous Sch-A2 and Sch-A3,with Sch-A2 displaying a gray CL image color with vague and uneven growth bands and Sch-A3 has a light gray CL image color with hardly any growth band.In contrast,Sch-B exhibits a‘core-rim’structure,with the core part(Sch-B1)being dark gray and displaying a uniform growth band,while the rim part(Sch-B2)is light gray and homogeneous.The normalized distribution pattern of rare earth elements in scheelite and Sr isotope data suggest that the early ore-forming fluid in the Nuri deposit originated from granodiorite porphyry and,later on,some country rock material was mixed in,due to strong water-rock interaction.Combining the O-H isotope data further indicates that the ore-forming fluid in the Nuri deposit originated from magmatic-hydrothermal sources,with contributions from metamorphic water caused by water-rock interaction during the mineralization process,as well as later meteoric water.The intense water-rock interaction likely played a crucial role in the precipitation of scheelite,leading to varying Eu anomalies in different generations of scheelite from the oxide stage to the quartz-sulfide stage,while also causing a gradual decrease in oxygen fugacity(fO2)and a slow rise in pH value.Additionally,the high Mo and low Sr contents in the scheelite are consistent with typical characteristics of magmatic-hydrothermal scheelite.Therefore,considering the geological features of the deposit,the geochemical characteristics of scheelite and the O-H isotope data published previously,it can be concluded that the genesis of the Nuri deposit belongs to porphyry-skarn deposit.展开更多
基金Supported by PetroChina Science and Technology Research and Technology Development Project(2021DJ0502)Open Research Project of Key Laboratory of Shale Gas Resources Exploration,Ministry of Natural Resources(Chongqing Institute of Geology and Mineral Resources)(KLSGE-2023).
文摘Based on geochemical data from natural gas samples across spring water systems and sedimentary basins,including Songliao,Bohai Bay,Sanshui,Sichuan,Ordos,Tarim and Ying-Qiong,this paper systematically compares the geochemical compositions of abiogenic versus biogenic gases.Emphasis is placed on the diagnostic signatures of abiogenic gases in terms of gas composition,and carbon,hydrogen and helium isotopes.The main findings are as follows.(1)In hydrothermal spring systems,abiogenic alkane gases are extremely scarce.Methane concentrations are typically less than 1%,with almost no detectable C^(2+)hydrocarbons.The gas is dominantly composed of CO_(2),while N_(2)is the major component in a few samples.(2)Abiogenic alkane gases display distinct isotopic signatures,including enriched methane carbon isotopic compositions(δ^(13)C_(1)>-25‰generally),complete carbon isotopic reversal(δ^(13)C_(1)>δ^(13)C_(2)>δ^(13)C_(3)>δ^(13)C_(4)),and enriched helium isotope(R/Ra>0.5,CH_(4)/^(3)He≤10^(6)generally).(3)The hydrogen isotopic composition of abiogenic alkane gases may be characterized by a positive sequence(δD_(1)<δD_(2)<δD_(3)),or a complete reversal(δD_(1)>δD_(2)>δD_(3)),or a V-shaped distribution(δD_(1)>δD_(2),δD_(2)<δD_(3)).The hydrogen isotopic compositions of methane generally show limited variation(about 9‰),possibly due to hydrogen isotopic exchange with connate water.(4)In terms of identifying gas origin,CH_(4)/^(3)He-R/Ra andδ^(13)CCO_(2)-R/Ra charts are more effective than CO_(2)/^(3)He-R/Ra chart.These new geological insights provide theoretical clues and diagnostic charts for the genetic identification of natural gas and further research on abiogenic gases.
基金supported by the National Natural Science Foundation of China(Grant No.42030607)the Beijing Municipal Science and Technology Commission(Grant No.Z251100004525005)the National Science Foundation/National Center for Atmospheric Research,and NASA(Grant No.80NSSC22M0129)。
文摘The growth trajectory of hailstones within clouds has remained elusive due to the inability to trace them directly,impeding the comprehension of their underlying growth mechanisms.This study investigated hailstone vertical growth trajectories by detecting the stable isotope signatures(2H and 18O compositions)of different shells in 27 hailstones from 9hailstorms,which allowed us to capture the ambient temperature during hailstone growth.The vertical growth trajectories were obtained by comparing the isotopic compositions of water condensate in clouds,derived from the Adiabatic Model,with those measured in hailstones.Although hailstone growth was primarily observed in the–10°C to–30°C temperature layer,the embryo formation height and subsequent growth trajectories significantly varied among hailstones.Embryos formed over a wide range of temperatures(–8.7°C to–33.4°C);four originated at temperatures above–15°C and 16originated at temperatures below–20°C,suggesting ice nuclei composed of bioproteins and mineral dust,respectively.Among the 27 measured hailstones,3 exhibited minimal vertical movement,16 exhibited a monotonic rise or fall,and the remaining 8 exhibited alternating up-down trajectories;only one experienced“recycling”during up-down drifting.Trajectory analysis revealed that similar-sized hailstones from a single storm tended to form at similar heights,whereas those larger than 25 mm in diameter exhibited at least one period of upward growth.Vertical trajectories derived from isotopic analysis were corroborated by radar hydrometeor observations.
文摘0 INTRODUCTION Uraninite and pitchblende are the most important ore minerals in nearly all types of uranium deposits.Therefore,the U-Pb isotopic system of uraninite and pitchblende are widely used in dating uranium deposits.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12325406,92261201,12404305,11974272)the Shannxi Province Natural Science Fundamental Research Project(Grant Nos.2023JC-XJ-03 and 23JSQ013)the Fundamental Research Funds for the Central Universities(Grant No.xzy022024040)。
文摘The two-body fragmentation dynamics of water isotopologues dications(H_(2)O^(2+),HOD^(2+),and D_(2)O^(2+))induced by200 eV electron impact is investigated.Two fragment ions and an emitted electron are detected in coincidence,and their momentum vectors are determined by employing a reaction microscope.The complete kinematical information of four two-body fragmentation channels of H^(+)+OH+,H^(+)+OD^(+),D^(+)+OH^(+),and D^(+)+OD+is obtained.By analyzing the projectile energy-loss spectrum,the initial electronic state of the two-body dissociation channel is determined.Upon examining the kinetic energy release(KER)distributions of the four fragmentation channels,a clear difference is found between the two-body fragmentation channel H^(+)+OD+and the other three channels.The isotopic effect in the two-body fragmentation is demonstrated by the analysis of the relative yields of the two-body fragmentation channels originating from different isotopologues,which shows preferential cleavage of the O-H bond over the O-D bond.These results provide deeper insight into the microscopic dynamic mechanisms in water radiolysis.
文摘Biomarker and stable carbon isotope analyses are presented for the Garau Formation of the Cretaceous Age,an important source rock in western Iran,to reveal its potential as an oilprone source rock.The C_(28)/C_(29)sterane ratio value range(0.72 to 0.83)of bitumen samples from the formation suggests that they were likely formed during phytoplankton blooms.Sterane,hopane,and isoprenoid/n-alkane ratios indicate that the formation's organic matter predominantly consists of algae,and bacteria,accompanied by some reworked material derived from higher plants.Due to the predominance of anoxic conditions and the actions of sulfate-reducing bacteria,the bitumen present is enriched with sulfur compounds.The percentages of saturates,aromatics,and nitrogen-sulfuroxygen(NSO)fractions in the bitumen samples classify them as naphthenic oils.Isotope analysis reveals that biodegradation and water-washing have reduced the concentrations of some volatile saturates and low molecular weight aromatics in the bitumen samples.These actions have resulted in distinctiveδ^(13)C values for the formation's kerogen and bitumen fractions.The formation's organic matter has been subjected to high-temperature thermal regimes and has entered the oil-generation window at the sampled localities,with vitrinite reflectance(%R_(C))varying between 0.7%and 0.75%.
基金financed by Yunnan Major Scientific and Technological Projects(Grant No.202202AG050006)the National Natural Science Foundation of China(Grant No.42462011)Projects of Yunnan Province Technology Hall(Grant No.202305AT350004).
文摘The Gejiu tin-copper-(tungsten)(Sn-Cu-(W))polymetallic district is located in the southwest of the W-Sn metallogenic belt in the western Youjiang Basin,Yunnan,Southwest China.Abundant W minerals have been identified in the region via exploration.However,metallogenic sources and evolution of W remain unclear,and the existing metallogenic model has to be updated to guide further ore prospecting.Elemental and Sr-Nd isotopic data for scheelites assist in the determination of sources and evolution of the W-mineralizing fluids and metals in the district.Based on field geological survey,the scheelites in the Gejiu district can be categorized into three types:altered granite(Type Ⅰ),quartz vein(Type Ⅱ)from the Laochang deposit,and skarn(Type Ⅲ)from the Kafang deposit.Types Ⅰ and Ⅱ scheelites have low molybdenum(Mo)and strontium(Sr)contents,and Type Ⅱ scheelite has lower Sr contents than Type Ⅰ as well as higher Mo and Sr contents than Type Ⅲ scheelites.Varying Mo contents across the scheelite types suggests that the oxygen fugacity varied during ore accumulation.Type Ⅰ and Type Ⅱ scheelites exhibit similar rare earth elements(REE)patterns;Type Ⅲ scheelite contains lower REE content,particularly HREE,compared with the other scheelites.All scheelites exhibit negative Eu anomalies in the chondrite-normalized REE patterns.As the W-mineralization and two-mica granite share close spatial and temporal relationships,the negative Eu anomalies were likely inherited from the two-mica granite.Type Ⅰ and Type Ⅱ scheelites display varied(^(87)Sr/^(86)Sr)_(82 Ma)(0.7090-0.7141)andε_(Nd)(82 Ma)(from−9.9 to−5.4)values,similar to those of granite.However,Type Ⅲ scheelite exhibits lower(^(87)Sr/^(86)Sr)_(82 Ma)(0.7083-0.7087)and lowerε_(Nd)(82 Ma)(from−10.5 to−6.9)values than the two-mica granite.This indicates that the two-mica granite alone did not provide the ore-forming fluids and metals and that the Type Ⅲ scheelite ore-forming fluids likely involved external fluids that were probably derived from carbonate rocks.The implication is that highly differentiated two-mica granites were the source of primary W-bearing metals and fluids,which is consistent with earlier research on the origin of Sn ore-forming materials.
基金financially supported by the Science Foundation of China University of Petroleum,Beijing(Nos.2462018YJRC030 and 2462020YXZZ020)the China Sponsorship Council(No.202306440071)。
文摘The widespread dolomite of the Sinian Dengying Formation in the Sichuan Basin(China)serves as one of the most important oil and gas reservoir rocks of the basin.Well WT1,as an exploration well,is recently drilled in the Kaijiang County,northeastern Sichuan Basin(SW China),and it drills through the Dengying Formation dolomite at the depth interval of 7500–7580 m.In this study,samples are systematically collected from the cores of that interval,followed by new analyses of carbon-oxygen isotope,major elements,trace elements,rare earth elements(REEs)and EP-MA.The Dengying Formation dolomites of Well WT1 haveδ13C values of 0.37‰to 2.91‰andδ18O values of-5.72‰to-2.73‰,indicating that the dolomitization fluid is derived from contemporary seawater in the near-surface environment,rather than the burial environment.Based on the REE patterns of EPMA-based in-situ data,we recognized the seawater-sourced components,the mixedsourced components and the terrigenous-sourced components,indicating the marine origin of the dolomite with detrital contamination and diagenetic alteration.Moreover,high Al,Th,and Zr contents indicate significant detrital contamination derived from clay and quartz minerals,and high Sr/Ba and Sr/Cu ratios imply a relatively dry depositional environment with extremely high seawater salinity,intensive evaporation,and strong influences of terrigenous sediment.
基金supported by the Scientific Research Fund of the Education Department of Yunnan Province(Grant Number:2019J0488).
文摘The End-Permian mass extinction(EPME),Earth’s most severe biocrisis,occurred proximal to the Permian-Triassic Boundary(PTB),with marine ecosystems experiencing catastrophic collapse.This study employs stable carbon(δ^(13)C)and oxygen isotopes from marine carbonates in the Haidai Section(Xuanwei,northeastern Yunnan)to decipher paleoenvironmental drivers.The well-preserved stratigraphic sequence encompasses the Upper Permian(Yangxin and Xuanwei Formations)transitioning into the Lower Triassic(Feixianguan and Jialingjiang Formations),providing a continuous marine sedimentary archive.A marked negativeδ^(13)C excursion(-9.66‰V-PDB)occurs at the PTB,initiating from+0.82‰with subsequent gradual recovery.This geochemical signature correlates with:90%reduction in primary productivity Biodiversity collapse exhibiting cluster extinction patterns Prolonged suppression of ecological recovery Concurrently,reconstructed seawater temperatures reveal extreme thermal fluctuations,surging from 23℃to 32℃at the PTB before precipitously declining to 16℃.These perturbations demonstrate coupled biogeochemical dynamics wherein:•Carbon cycle destabilization disrupted nutrient fluxes.•Temperature oscillations exceeded marine taxa thermal tolerances.•Synergistic environmental stresses amplified extinction selectivity.Theδ^(13)C-temperature covariance(r^(2)=0.085)establishes mechanistic linkages between physicochemical perturbations and biotic responses.Our findings demonstrate that the EPME was driven by positive feedback loops in which:Volcanic CO₂emissions triggered carbonate saturation decline Thermal stratification exacerbated anoxia Biogeochemical cycling perturbations suppressed primary producers This integrated geochemical record from the Haidai Section provides critical insights into environment-organism coevolution during Phanerozoic Earth’s most profound mass extinction.
基金supported by National Natural Science Foundation of China(Grant No.42473017)Hong Kong RGC grants(JLFS/P-702/24 and 17308023)China Geological Survey project(Grant No.DD20242037).
文摘To investigate the stable chromium(Cr)isotope variations during melt percolation in the mantle,we ana-lyzed the Cr isotopic compositions of fresh ultramafic rocks from the Balmuccia and Baldissero peridotite massifs located in the Italian Alps.These massifs represent fragments of the subcontinental lithospheric mantle.The samples collected included lherzolites,harzburgites,dunites,and pyroxenites.Lherzolites,formed through 5%-15%fractional melting of a primitive mantle source,exhibited δ^(53)Crvalues ranging from−0.13‰±0.03‰to−0.03‰±0.03‰.These values correlated negatively with Al_(2)O_(3)content,sug-gesting that partial melting induces Cr isotopic fractionation between the melts and residual peridotites.Harzburgites and dunites,influenced by the silicate melt percolation,displayed distinctδ^(53)Cr values.Notably,dunites not spatially associated with the pyroxenite veins exhibited slightly elevatedδ^(53)Cr val-ues(−0.05‰±0.03‰to 0.10‰±0.03‰)relative to lherzolites.This difference likely resulted from pyroxene dissolution and olivine precipitation during melt percolation processes.However,one dunite sample in direct contact with pyroxenite veins showed lowerδ^(53)Cr values(−0.26‰±0.03‰),possibly owing to the kinetic effects during silicate melt percolation.Pyroxenites are formed through the interac-tion of basaltic melts with the surrounding peridotite via a metasomatic reaction or crystallization in a vein.Most of theirδ^(53)Cr values(−0.26‰±0.03‰to−0.13‰±0.03‰)are positively correlated with MgO contents,suggesting that they were influenced by magmatic differentiation.However,two subsam-ples from a single clinopyroxenite vein exhibit anomalously lowδ^(53)Crvalues(−0.30‰±0.03‰and−0.43‰±0.03‰),which are attributed to kinetic isotopic fractionation during melt-percolation pro-cesses.Our findings suggest that melt percolation processes in the mantle contribute to the Cr isotopic heterogeneity observed within the Earth’s mantle.
基金supported by the National Natural Science Foundation of China(Grant No.41872219).
文摘The Xingyuan large fluorite deposit in Fengning,Hebei Province,China,is a significant deposit in the North Hebei-West Liaoning fluorite mineralization belt.The ore bodies are structurally controlled and occur in fault zones near granitic porphyry veins.Previous studies have focused on the geology and ore-controlling factors,whereas the general features of the hydrothermal systems that contributed to the formation of the deposit remain unclear.This study investigated the nature,origin,and evolution of mineralizing fluids in the Fengning deposit,based on fluid inclusion and H-O isotope data.The fluid inclusions in fluorite are mostly H2O-rich,gas-liquid,two-phase inclusions,along with a few three-phase inclusions containing halite daughter crystals and CO_(2)gas.The ore-forming fluid was variable in homogenization temperature(108-388°C),salinity(0.2-47.4 wt%NaCl equivalent),and density(0.58-1.11 g/cm^(3)),which indicate it was a H2O-NaCl-CO_(2)system of moderate-low temperature,low salinity,and low density.Fluorite H-O isotopes(δD_(V-SMOW)=−123.5‰to−111.8‰;δ^(18)O_(V-SMOW)=−10.3‰to−6.5‰),temperature data,and fluid compositions indicate the mineralizing fluid was initially dominated by magmatic waters,but then experienced a large influx of meteoric waters.The fluid temperature and salinity decreased and the density increased from the early to late stages of mineralization.The main mechanisms of fluorite precipitation were water-rock reactions and fluid cooling.The Xingyuan fluorite deposit is a post-magmatic hydrothermal deposit.
基金suppor ted by Yunnan Major Scientific and Technological Projects(Grant No.202202AG050006)the Personnel Training Project of Kunming University of Science and Technology(Grant No.KKZ3202221022)。
文摘The Guanfang large-scale W deposit is located in the W polymetallic ore concentration area of Bozhushan in southeastern Yunnan,China.Despite extensive research,the fluid evolution process of the deposit remains ambiguous,leading to controversy regarding its genesis.This study conducted a detailed field geological survey,with systematic sampling of the KT6 orebody,to delineate mineralization stages.Fine mineralogy work,including the use of CL images of scheelite,in-situ LA-ICP-MS trace elements,and Sr isotopes,was carried out on diff erent generations of scheelite formed in various stages.The findings identified the evolution of fluids in the mineralization process,shedding light on the genesis of the deposit.The study revealed four mineralization stages at the Guanfang W deposit:prograde skarn stage,retrograde skarn stage,quartz-sulfide stage,and carbonate-fluorite stage.Diff erent generations of scheelite(Sch I,Sch II,Sch III)were observed in the first three stages,displaying distinct chondrite-normalized REE patterns.The REE of Sch I mainly substituted into the Ca site by REE^(3+)+□_(Ca),and there may be a similar substitution of Nb for REE,whereas it is not the main substitution method.The REE of Sch II mainly enter the scheelite lattice in the form of REE 3++Na+,and there may be a substitution of Nb for REE isomorphism.In the early stage,The REE of Sch III was mainly replaced by Nb for REE isomorphism,while in the later stage,the replacement mode of REE^(3+)+□_(Ca)coexisted with it.The Mo content in scheelite,along with the corresponding Eu anomalies in both scheelite and garnet,collectively imply that the ore-forming fluids during various mineralization stages were predominantly oxidizing,with only slight reducibility observed in Sch II.The in-situ Sr isotope ratios of scheelite concentrates ranged from 0.7093 to 0.7153,resembling those of the Bozhushan granite,indicating a relationship between W mineralization and granite.In addition,the Y/Ho ratios of scheelite from various mineralization stages exhibit a narrow range(19-31),with a pronounced correlation between the contents of Y and Ho and a similar trend in their variation.This consistency suggests that the Guanfang deposit has undergone a uniform or comparable evolutionary process,implying a stable ore-forming fluid across diff erent mineralization stages.
基金Supported by the National Natural Science Foundation of China(41472120)General Project of National Natural Science Foundation of China(42272188)+1 种基金Special Fund of PetroChina and New Energy Branch(2023YQX10101)Petrochemical Joint Fund of Fund Committee(U20B6001)。
文摘Exploration and development of large gas fields is an important way for a country to rapidly develop its natural gas industry.From 1991 to 2020,China discovered 68 new large gas fields,boosting its annual gas output to 1925×108m3in 2020,making it the fourth largest gas-producing country in the world.Based on 1696 molecular components and carbon isotopic composition data of alkane gas in 70 large gas fields in China,the characteristics of carbon isotopic composition of alkane gas in large gas fields in China were obtained.The lightest and average values ofδ^(13)C_(1),δ13C2,δ13C3andδ13C4become heavier with increasing carbon number,while the heaviest values ofδ^(13)C_(1),δ13C2,δ13C3andδ13C4become lighter with increasing carbon number.Theδ^(13)C_(1)values of large gas fields in China range from-71.2‰to-11.4‰(specifically,from-71.2‰to-56.4‰for bacterial gas,from-54.4‰to-21.6‰for oil-related gas,from-49.3‰to-18.9‰for coal-derived gas,and from-35.6‰to-11.4‰for abiogenic gas).Based on these data,theδ^(13)C_(1)chart of large gas fields in China was plotted.Moreover,theδ^(13)C_(1)values of natural gas in China range from-107.1‰to-8.9‰,specifically,from-1071%o to-55.1‰for bacterial gas,from-54.4‰to-21.6‰for oil-related gas,from-49.3‰to-13.3‰for coal-derived gas,and from-36.2‰to-8.9‰for abiogenic gas.Based on these data,theδ^(13)C_(1)chart of natural gas in China was plotted.
基金financially supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0802)。
文摘Lack of information regarding lithium(Li)crystal chemistry in numerous minerals,especially those containing trace amounts of Li(ranging from a few to tens of ppm),limits our understanding of Li isotopic fractionation in pegmatites.In this study,we examined the Li isotopic composition and Li content in various Li-poor(e.g.,quartz or feldspar)together with Li-rich(sopdumene or lepidolite)mineral phases within granitic pegmatites.We compiled a comprehensive dataset,encompassing a broad spectrum of Li contents(ranging from a few to tens of thousands of ppm)and Li isotopic values(-8‰to 41‰).The minerals exhibit distinct Li isotopic signatures.Specifically,elbaite and beryl show the highest values,while biotite displays a negative average.Compared to individual minerals,whole rocks demonstrate lower Li isotopic values,with pegmatites exhibiting the highest and non-granitic pegmatite wall rocks showing the lowest.Our study also uncovers a clear“V”shape relationship between Li isotopic values and logarithm of Li contents,with different mineral groups occupying specific regions within this shape.Furthermore,a significant correlation was observed between average Li isotopic values and Li-O(OH,F)bond lengths in various minerals.These discoveries underscore the crucial role of crystal chemistry in shaping the Li isotopic behavior in pegmatites from a statistical perspective.
基金Supported by the Natural Science Foundation of Shaanxi Province(2024JC-ZDXM-22,2020JM-311)the Project of China Geological Survey(DD20240128,DD20230284,DD20221636)。
文摘1.Objective The Altay Orogenic Belt in Xinjiang,China is located in the west of the Central Asian Orogenic Belt and in the transition zone between the Siberian Plate and the Kazakhstan-Junggar Plate,extending approximately 500 km in northern Xinjiang,China(Fig.1a).The Altay Orogenic Belt has undergone two-way accretion of the Paleozoic crust and the Meso-Cenozoic intracontinental orogeny,leading to the formation of large numbers of intermediate-acid intrusions.More than 100000 pegmatite veins have been discovered in the intermediate-acid intrusions,and they constitute an important rare metal metallogenic belt of China(Fig.1b).
基金supported by National Key R&D Program of China(2021YFA1502803)the National Natural Science Foundation of China(NSFC)(21972066,91745202)+3 种基金NSFC-Royal Society Joint Program(21661130149)L.P.thanks the Royal Society and Newton Fund for a Royal Society-Newton Advanced Fellowshipsupported by the Research Funds for the Frontiers Science Centre for Critical Earth Material Cycling,Nanjing Universitya Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Recent advances in utilizing ^(17)O isotopic labeling methods for solid-state nuclear magnetic resonance(NMR)investigations of metal oxides for lithium-ion batteries have yielded extensive insights into their structural and dynamic details.Herein,we commence with a brief introduction to recent research on lithium-ion battery oxide materials studied using ^(17)O solid-state NMR spectroscopy.Then we delve into a review of ^(17)O isotopic labeling methods for tagging oxygen sites in both the bulk and surfaces of metal oxides.At last,the unresolved problems and the future research directions for advancing the ^(17)O labeling technique are discussed.
文摘Early Palaeozoic Cambrian A-type Kathalguri Granites in the Mikir Hills of northeastern (NE) India were studied to better understand the geodynamic settings in this region. This research presents new whole-rock geochemical and Sr, Nd, Pb isotopic data for the Cambrian granites in the Kathalguri Granite in Mikir Hills. The Kathalguri Granite shows geochemical characteristics of high SiO2, K2O and low FeOT, MgO, CaO, and P2O5 compositions. They belong to a high K Shoshonite to ultra-potassic series and display a weak metaluminous to peraluminous feature with A/CNK values of 0.83 to 1.02 with corundum and anorthite normative. FeOT/MgO varies from 2.93 - 7.49, is moderately oxidized and belongs to magnetite series. The rocks have a high ΣREE composition of 370.80 - 1353.23 ppm (average 568.55) and are enriched in LREE with flat HREE and (La/Yb)N values of 8.10 - 18.99, and display obvious strong negative Eu anomalies. Trace elements of the studied granites are characterized by enrichment in Rb, Th, U, Pb, Hf, and Sm, and depletion of Ba, Nb, Ta, and Sr. They display geochemical features of high Zr + Y + Nb + Ce values (241 - 934 ppm) and Ga/Al ratios 2.49 - 3.01 consistent with A-Type granites. Based on particular geochemical features, such as high Rb/Nb (3.10 - 19.53) and Low Y/Nb (0.09 - 2.28), Kathalguri Granite can be further classified as an A1-type subgroup. Granites display relatively low Sr (N ratio varying between 0.53 - 0.89 suggesting that the melts generated at greater depths (18 - 40 km), and fractionation at low pressures (−3 and total HGU 98.96 to 214.20. Kathalguri Granite dated by Rb-Sr isotopic isochrone as 489 ± 19 Ma with an initial 87Sr/86Sr 0.7199 ± 0.0017 and MSWD of 4.1, εSr(I) varied between 161.62 - 332.08 suggests that the Kathalguri Granite have originated from partial melting of ancient, evolved continental crustal material. The Sm-Nd Systematics has given a depleted mantle model (TDM) age ranging from 1733 - 2063 Ma with high negative εNd(t) values (−10.39 to −15.18) also hint at some heterogeneity or multiple source contributions in the melting process of the protolith. Xenoliths of older mafic rocks and Barapani arenites are seen within the Kathalguri Granite and are also supported by geochemical signatures of recycled crustal materials both mafic and sedimentary. It formed during the Cambrian reorganization of lithospheric plate motion related to the Pan-African-Braziliano event.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2022QZKK0202)the National Natural Science Foundation of China(Grant No.U22A20573)the Fundamental Research Funds for the Central Universities(Grant No.B230201014).
文摘Lithium(Li),a crucial mineral resource for modern high-tech industries,is notably abundant in the northern Tibetan Plateau,primarily within lithium-rich salt lakes.However,the exploration and development of these resources are hindered due to an incomplete understanding of their nature and origin.Here we present results from a comprehensive study on the hydrochemical parameters,whole-rock geochemistry,H-O isotopes,and Li concentrations in surface brine,river water,geothermal springs,and associated rocks from two representative lithium-enriched salt lakes,the Laguo Co(LGC)and Cangmu Co(CMC)in Xizang to understand the genetic mechanisms.Our water-salt balance calculations and H-O isotopic analysis reveal that Li in LGC and CMC primarily originates from the Suomei Zangbo(SMZB,~91%)and Donglong Zangbo(DLZB,~75%)rivers,respectively.It is estimated that the LGC and CMC took a minimum of 6.0 ka and 3.0 ka to accumulate their current lithium resources,respectively.The distinct geological characteristics reflect evolutionary differences between the two lakes,suggesting diverse lithium sources and enrichment processes.The high lithium ion concentration and light lithium isotope composition in the SMZB river waters indicate the genetic relationship with lithium-enriched geothermal springs in the Tibetan Plateau.Our results suggest that lithium in the LGC originates from lithium-enriched geothermal springs and is primarily supplied through the small-scale SMZB river.In contrast,the formation and evolution of CMC are influenced by the northern Lunggar rifts,receiving a prolonged and stable input from the DLZB,resulting in high lithium concentrations and isotopic values.The absence of lithium-enriched geothermal springs and the prevalence of silicate rocks in the CMC catchment suggest that lithium may be sourced from the weathering of silicate rocks,such as granitic pegmatite veins containing lithium-rich beryl,widely distributed in the upstream area of DLZB.The forward modeling approach,quantifying the contribution fractions of different reservoirs(atmospheric precipitation,silicate,carbonate,and evaporite),indicates that the distinct lithium concentrations in the mainstream(>1 mg/L)and tributaries(<0.1 mg/L)are positively correlated with the ratio of silicate contributions to carbonate contributions,suggesting that dissolved lithium in river waters primarily originates from the weathering and dissolution of silicate rocks.The distinct sources and enrichment mechanisms of lithium in these two salt lakes are attributed to various evolutionary processes,topographical features,hydrological factors,fundamental geological settings,and tectonic histories,despite their spatial proximity.Furthermore,our study highlights the significant role of rivers in the formation of young salt lakes,in addition to geothermal springs.
基金funded by the project of China Geological Survey(Grant No.DD20221677-2)the Central Public-Interest Scientific Institution Basal Research Fund(Grant No.JKYQN202307)。
文摘Geothermal resources are increasingly gaining attention as a competitive,clean energy source to address the energy crisis and mitigate climate change.The Wugongshan area,situated in the southeast coast geothermal belt of China,is a typical geothermal anomaly and contains abundant medium-and low-temperature geothermal resources.This study employed hydrogeochemical and isotopic techniques to explore the cyclic evolution of geothermal water in the western Wugongshan region,encompassing the recharge origin,water-rock interaction mechanisms,and residence time.The results show that the geothermal water in the western region of Wugongshan is weakly alkaline,with low enthalpy and mineralization levels.The hydrochemistry of geothermal waters is dominated by Na-HCO_(3)and Na-SO_(4),while the hydrochemistry types of cold springs are all Na-HCO_(3).The hydrochemistry types of surface waters and rain waters are NaHCO_(3)or Ca-HCO_(3).The δD and δ^(18)O values reveal that the geothermal waters are recharged by atmospheric precipitation at an altitude between 550.0 and 1218.6 m.Molar ratios of maj or solutes and isotopic compositions of^(87)Sr/^(86)Sr underscore the significant role of silicate weathering,dissolution,and cation exchange in controlling geothermal water chemistry.Additionally,geothermal waters experienced varying degrees of mixing with cold water during their ascent.Theδ^(13)C values suggest that the primary sources of carbon in the geothermal waters were biogenic and organic.Theδ^(34)S value suggests that the sulfates in geothermal water originate from sulfide minerals in the surrounding rock.Age dating using 3H and^(14)C isotopes suggests that geothermal waters have a residence time exceeding 1 kaBP and undergo a long-distance cycling process.
基金supported by the National Natural Science Foundation of China (Nos.U1704241 and 42007175)the Plan for Scientific Innovation Talent of Henan Province (No.194200510010)the Science Research Funds for the Universities of Henan Province (No.NSFRF200326)。
文摘Nitrogen deposition is an important means of exogenous nitrogen input in reservoir water.Agricultural activities around the reservoir lead to a sharp increase in the concentration of ammonia in the atmosphere,which poses a threat to the reservoir water body.Clarifying the contribution of agricultural ammonia release to atmospheric NH_(x)(gaseous NH_(3)and particulate NH_(4)^(+)),in the reservoir area can provide a theoretical foundation for local reactive nitrogen control.We collected atmospheric NH_(3)and NH_(4)^(+)samples during the agricultural periods and analyzed the isotopic characteristics of atmospheric NH_(x)and the contribution rates of different ammonia sources in the Xichuan area of the Danjiangkou Reservoir.The results showed that the initialδ~(15)N values of NH_(3)(-30.0‰to–7.2‰)and particulate NH_(4)^(+)(–33‰to+4.9‰for finer and coarser particles,respectively)are different,and their contribution ratios from dissimilar ammonia sources are also different,among which NH_(4)^(+)is more susceptible to meteorological factors.However,since the atmospheric NH_(x)in the Xichuan area is mainly gaseous NH_(3),the final sources of atmospheric ammonia nitrogen source depend on gaseous NH_(3).Agricultural sources(59%-74%)were the main NH_(3)sources in this area.Among them,the fertilizer use emission was dominant;it had the highest contribution rate in summer during the agricultural period and a more prominent impact in areas with less human interference.Reasonable regulation of the application of high-ammonia releasing fertilizer,especially during the agricultural period in summer,is an effective way to reduce the threat of atmospheric ammonia to water health.
基金financially supported by the National Key Research and Development Program of China(Grant No.2021YFC2901903)the Geological Comprehensive Research Project of China’s Metallurgical Geology Bureau(Grant No.[2022]CMGBDZYJ005),the National Natural Science Foundation of China(Grant No.42002097)the Geological Investigation Project(Grant Nos.DD20230031,DD20221690,DD20230049,DD20230337).
文摘The Nuri deposit is the only Cu-W-Mo polymetallic deposit with large-scale WO3 resources in the eastern section of the Gangdese metallogenic belt,Xizang,China.However,the genetic type of this deposit has been controversial since its discovery.Based on a study of the geological characteristics of the deposit,this study presents mineralization stages,focusing on the oxide stage and the quartz-sulfide stage where scheelite is mainly formed,referred to as Sch-A and Sch-B,respectively.Through LA-ICP-MS trace element and Sr isotope analyses,the origin,evolutionary process of the oreforming fluid and genesis of the ore deposit are investigated.Scanning Electron Microscope-Cathodoluminescence(SEMCL)observations reveal that Sch-A consists of three generations,with dark gray homogenous Sch-A1 being replaced by relatively lighter and homogeneous Sch-A2 and Sch-A3,with Sch-A2 displaying a gray CL image color with vague and uneven growth bands and Sch-A3 has a light gray CL image color with hardly any growth band.In contrast,Sch-B exhibits a‘core-rim’structure,with the core part(Sch-B1)being dark gray and displaying a uniform growth band,while the rim part(Sch-B2)is light gray and homogeneous.The normalized distribution pattern of rare earth elements in scheelite and Sr isotope data suggest that the early ore-forming fluid in the Nuri deposit originated from granodiorite porphyry and,later on,some country rock material was mixed in,due to strong water-rock interaction.Combining the O-H isotope data further indicates that the ore-forming fluid in the Nuri deposit originated from magmatic-hydrothermal sources,with contributions from metamorphic water caused by water-rock interaction during the mineralization process,as well as later meteoric water.The intense water-rock interaction likely played a crucial role in the precipitation of scheelite,leading to varying Eu anomalies in different generations of scheelite from the oxide stage to the quartz-sulfide stage,while also causing a gradual decrease in oxygen fugacity(fO2)and a slow rise in pH value.Additionally,the high Mo and low Sr contents in the scheelite are consistent with typical characteristics of magmatic-hydrothermal scheelite.Therefore,considering the geological features of the deposit,the geochemical characteristics of scheelite and the O-H isotope data published previously,it can be concluded that the genesis of the Nuri deposit belongs to porphyry-skarn deposit.
