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
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
The pervasively distributed granitoids in South China contributed greatly to regional polymetallic mineralization,including tungsten,tin,copper,gold,rare metals,and rare earth elements(REEs).To ascertain the dynamic b...The pervasively distributed granitoids in South China contributed greatly to regional polymetallic mineralization,including tungsten,tin,copper,gold,rare metals,and rare earth elements(REEs).To ascertain the dynamic backgrounds,rock types and genesis of the parent rocks related to the Early-Middle Jurassic ionic rare earth mineralization,typical deposits at Muzishan,Xiahu,and Zudong were investigated by conducting petrographic,geochronologic,whole-rock geochemical,and Sr-Nd-Pb isotope analyses,which found that the parent rocks from the Muzishan deposit were the A1-type K-feldspar granite(~195 Ma),from the Zudong deposit were the A2-type monzogranite(~171 Ma),and from the Xiahu deposit were the I-type monzogranite(~167 Ma).All the three granitic rocks underwent different degrees of fractionation,with the Xiahu granite experiencing the highest degree,followed by the Zudong granite,and the Muzishan granite undergoing the lowest degree.The Muzishan granite was concluded to be formed under an intraplate extensional tectonic regime influenced by the hotspots or the mantle plume.The Zudong granite was formed in a post-arc extensional setting related to subduction-collision-rollback of the paleo-Pacific Plate,which caused upwelling of the asthenosphere,thinning of the lithosphere,and partial melting of crustal materials.The Xiahu granite was generated under a transitional tectonic setting of extension and compression,triggered by delamination and rollback of the paleo-Pacific Plate.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
Permian—Triassic granitoids are widely distributed along the Jinshajiang suture belt,eastern Xizang,and are regarded as the result of the tectonic-magmatic activity associated with the evolution of Paleo-Tethys Ocean...Permian—Triassic granitoids are widely distributed along the Jinshajiang suture belt,eastern Xizang,and are regarded as the result of the tectonic-magmatic activity associated with the evolution of Paleo-Tethys Ocean.This paper focuses on the high-K calc-alkaline I-type Rennong(~235 Ma)and Jiaduoling(~232 Ma)granitoid plutons,eastern Xizang,which are enriched in light rare earth elements(LREEs)and large ion lithophile elements(LILEs),but depleted in high field strength elements(HFSEs)with moderate-weak negative Eu anomalies(0.61–0.90).The Rennong granites are characterized by uniform zircon ε_(Hf)(t)values(-7.3 to-3.5)and negative ε_(Nd)(t)values(-7.6 to-5.7),with old two-stage Nd model ages(T_(DM2)=1.51-1.46 Ga)and was likely formed by partial melting of the basement rocks,whereas the Jiaduoling rock samples have variable zircon ε_(Hf)(t)values(-5.7 to+5.5)but negativeεNd(t)values(-7.6 to-7.7)and are proposed to be formed by hybridization of mantle-derived mafic magma,Rennong felsic magma and sediments.Mafic microgranular enclaves(MMEs)in the Jiaduoling granitic rocks,have similar zircon U-Pb ages(~237 Ma)and zircon ε_(Hf)(t)values(-4.4 to+6.3)to the host rocks,indicating that zircons in the MMEs were actually xenocrysts that formed at an early stage in the granitic magma chamber.These results reveal that the break-off of the Jinshajiang oceanic slab beneath Changdu(Qamdo)-Simao Block was in a post-collisional setting,resulted in the upwelling of asthenosphere in the Late Triassic,and then,generated the wide-spread intermediate-felsic magmatism along the Jinshajing belt,including the Rennong and Jiaduoling plutons.展开更多
The lithospheric thinning and huge gold mineralization in the Jiaodong Peninsula is intensively studied,aiming to better understand the geodynamic setting of the magmatic petrogenesis and the relationship between magm...The lithospheric thinning and huge gold mineralization in the Jiaodong Peninsula is intensively studied,aiming to better understand the geodynamic setting of the magmatic petrogenesis and the relationship between magmatism and large-scale mineralization.Thus,we conducted detailed research on the Weideshan intrusions in the Jiaodong region,including fi eld investigations,geochemical,geochronological and Hf isotope analysis,to reveal the tectonic implications for the destruction of the eastern North China Craton(NCC).The Weideshan intrusions consist of quartz monzodiorite,quartz monzonite and monzogranite.The SHRIMP zircon U-Pb dating results show that the Weideshan intrusions are emplaced at 115–112 Ma,namely,in the late Early Cretaceous period.Rocks of Weideshan intrusions are high-K calc-alkaline series and metaluminous granites.The trace elements are characterized by enrichment of Rb,Ba,Sr and LREE,with unobvious Eu anomalies and depletion of Nb,Ta,Zr,Hf and Ti.The contents of Ba and Sr are(913.00–1562.00)/1199.29μg/g and(373.00–793.00)/536.71μg/g,respectively,showing the features of high Ba–Sr granites(HBS).Development of numerous dark enclaves and negativeεHf(t)values(−17.93 to−12.19)indicate that the Weideshan granites originate from the mixture of crustal-derived felsic magma from partial melting of the Paleoproterozoic crust and alkali-rich magma from the enriched mantle.The generation of the Weideshan granites was closely related to the asthenospheric upwelling during the lithosphere thinning of the NCC in the late Mesozoic.展开更多
The Arabian-Nubian Shield(ANS)serves as a key geological archive,preserving the tectono-thermal evolution associated with the Rodinia breakup(∼900–800 Ma)and Gondwana formation(∼800–620 Ma).The Katherina Ring Comp...The Arabian-Nubian Shield(ANS)serves as a key geological archive,preserving the tectono-thermal evolution associated with the Rodinia breakup(∼900–800 Ma)and Gondwana formation(∼800–620 Ma).The Katherina Ring Complex(KRC),located in the Sinai Peninsula,Egypt(northern ANS),exemplifies continental growth through multistage magmatism and orogenesis,spanning the Tonian to Ediacaran periods(∼900–530 Ma).Despite its importance,debates persist regarding the nature,age,crustal characteristics,and magma source evolution of its constituent units.Situated in the northwestern part of the KRC,the Wadi Rofaiyed Cu deposit offers an exceptional natural laboratory for investigating continental crust formation during this interval,owing to its superb exposure and preservation.This study integrates detailed fieldwork,petrographic analyses,whole-rock geochemistry,Sr-Nd isotopes,and in situ zircon U-Pb-Lu-Hf isotopic data.It aims to(i)establish a robust chronological framework for the unmetamorphosed plutonic rocks of the KRC,(ii)advance the understanding of associated geodynamic processes,and(iii)elucidate the episodic magmatism events.The findings show that Wadi Rofaiyed juvenile crust developed in four main phases:(i)a subduction-accretionary phase(∼755 Ma)characterized by intense calc-alkaline magmatism,originating from the partial melting of mafic lower crust;(ii)a syn-collisional phase(∼630 Ma)occurred during the collision between the Saharan metacraton and the younger ANS crust,producing I-type granitoids formed through magma mixing and crustal anatexis;(iii)a post-collisional phase characterized by intermediate I-type(∼595 Ma)to felsic A-type alkaline magma(∼594 Ma),originated from the partial melting of the overthickened lower crust corresponding to lithospheric delamination;and(iv)an anorogenic phase(∼530 Ma)related to the final amalgamation of Greater Gondwana.Isotopic analyses across all four magmatic phases reveal low initial^(87)Sr/^(86)Sr(0.702648–0.703311)and positiveε_(Hf)(t)(+2.84 to+7.78)andε_(Nd)(t)(+2.61 to+5.21)values,consistent with lower crustal sources with depleted mantle-like signatures.The model ages(T_(DM2))for these magmatic rocks derived from zircon Hf(1.2–1.5 Ga)and whole-rock Nd isotopes(0.96–1.17 Ga)support a predominantly juvenile crustal origin.These findings underscore the multistage tectono-magmatic evolution of the northern ANS,advancing our understanding of obduction-accretion dynamics and crustal development during the Neoproterozoic.展开更多
The Tong’an-Baishuidong mining district(TBMD),located in the eastern section of the Jiangnan Orogen,is a newly discovered granite-type lithium mining district.Thisstudy presents new monazite U-Pb chronological,whole-...The Tong’an-Baishuidong mining district(TBMD),located in the eastern section of the Jiangnan Orogen,is a newly discovered granite-type lithium mining district.Thisstudy presents new monazite U-Pb chronological,whole-rock geochemical,and Nd-Pb isotopic data to reveal the petrogenesis and geodynamic setting of the Wutang granites in the TBMD.The monazite U-Pb age of 145.8±1.0 Ma indicates that the granites were emplaced at the end of the Late Jurassic.Whole-rock geochemical results demonstrate that the Wutang granites are enriched in SiO_(2)(72.80-73.40 wt%)but depleted in CaO(0.44-0.90 wt%)and MgO+TiO_(2)+TFeO(1.79-2.05 wt%).These granites exhibit negative Eu anomalies(δEu=0.3−0.4)and high aluminum saturation indexes(A/CNK=1.2−1.6),differentiation indexes(DI=90-92),and Rb/Sr ratios(4.7-8.1).They also have moderate Ba contents(239-278 ppm)and low Sr contents(52.7-82.0 ppm)as well as low Nb/Ta(2.2-5.3)and Zr/Hf(21.3-31.5)ratios.All these indicate that they are highly fractionated granites.Additionally,these granites contain 5-10 wt%muscovite but no hornblende,with calculated corundum contents of 2.3-5.5 wt%.They have low high-field strength element(HFSE)contents(Zr+Nb+Ce+Y=182-202 ppm)and zircon saturation temperatures(700-770℃),with Th and Y negatively linked with Rb.These petrographic and geochemi-cal features further reveal that the Wutang granites belong to highly fractionated S-type granites.TheεNd(t)values of these granites range from−9.03 to−8.23,corresponding to two-stage model ages(T DM2)of 1488-1553 Ma.The initial Pb isotope ratios are:(206 Pb/^(204)Pb)i=18.38-18.55,(^(207)Pb/^(204)Pb)i=15.67-15.68,and(^(208)Pb/^(204)Pb)i=38.62-38.67.These Nd-Pb isotopic results demonstrate that the parental magma originated from the partial melting of ancient crustal materials.In the meantime,the TBMD in the eastern section of the Jiangnan Orogen was in a compression-extension transitional setting associated with the episodic subduction of the Paleo-Pacific Plate.展开更多
The deep geologic processes between the Xing’an-Mongolian Orogenic Belt and the North China Craton in the Mesozoic are crucial to reveal the magmatic and tectonic evolution and their constraints on mineralization in ...The deep geologic processes between the Xing’an-Mongolian Orogenic Belt and the North China Craton in the Mesozoic are crucial to reveal the magmatic and tectonic evolution and their constraints on mineralization in the Jiapigou-Haigou collage zone.In this paper,We have presented the geochronology,geochemistry and Sr-Nd-Hf isotopic compositions of the Middle Jurassic granitic complexes in the Songjianghe area,Jilin Province.The granitic complexes can be categorized into four groups based on their geologic characteristics,with corresponding zircon U-Pb isotope ages of 177 Ma,172 Ma,169 Ma and 168-167 Ma,respectively.These granitoids exhibit calcalkaline to high-K calc-alkaline,metaluminous to weakly peraluminous Ⅰ-type characteristics,which show relative enrichment in LILEs(Rb,Sr,Ba)and depletion in HFSEs(Nb,Zr).Geochemical analyses reveal high initial^(87)Sr/^(86)Sr ratios of 0.70633-0.70740,coupled with lowεNd(t)values ranging from−10.65 to−13.23.The zircon analyses show similarly negativeεHf(t)values ranging from−16.9 to−3.2.The integrated elemental and Hf-Sr-Nd isotopic signatures demonstrate that the primitive magmas of the four group rocks were primarily derived from partial melting of thickened Archean lower crust,with the exception of the Group Ⅳ rocks,which exhibit significant evidence of crustal contamination.The residual mineral assemblages during the magma-forming process varied from amphibole to eclogite facies.These findings indicate that magmatism in the Songjianghe region likely resulted from the accretion and delamination of the Archean crust in the collage zone during the subduction of the Paleo-Pacific Plate beneath the Eurasian continent.展开更多
Detrital zircon U-Pb geochronology has become the gold standard in evaluating source to sink relationships in sedimentary basins. However, the physical and chemical robustness of zircon, which make it such a useful mi...Detrital zircon U-Pb geochronology has become the gold standard in evaluating source to sink relationships in sedimentary basins. However, the physical and chemical robustness of zircon, which make it such a useful mineral for provenance studies, is also a hindrance as zircon can be recycled through numerous sedimentary basins, thus obscuring the first cycle source to sink relationship. An elegant approach to addressing this potential issue is to compare the Pb isotope composition of detrital K-feldspar, a mineral which is unlikely to survive more than one erosion-transport-deposition cycle, with that of magmatic K-feldspar from potential basement source terranes. Here we present new in situ Pb isotope data on detrital K-feldspar from two Proterozoic arkosic sandstones from Western Australia, and magmatic K-feldspar grains from potential igneous source rocks, as inferred by the age and Hf isotope composition of detrital zircon grains. The data indicate that the detrital zircon and K-feldspar grains could not have been liberated from the same source rocks, and that the zircon has most likely been recycled through older sedimentary basins. These results provide a more complete understanding of apparently simple source to sink relationships in this part of Proterozoic Western Australia.展开更多
The Mesozoic porphyry assemblage in the Jinduicheng area is a special molybdenum area in China, the Mo deposits, including the Jinduicheng, Balipo, Shijiawan, Huanglongpu, are distributed. The emplacement age and geoc...The Mesozoic porphyry assemblage in the Jinduicheng area is a special molybdenum area in China, the Mo deposits, including the Jinduicheng, Balipo, Shijiawan, Huanglongpu, are distributed. The emplacement age and geochemical features of the granites in the Jinduicheng area can provide essential information for the exploration and development of the porphyry molybdenum deposit. In this study, we report LA-ICP-MS zircon U-Pb age and zircon Hf isotopic compositions of granite porphyries from the Jinduicheng area, and provide insights on the petrogensis and source characteristics of the granites. The results show that the zircon U-Pb ages of the Jinduicheng granite porphyry （143±1 Ma） and the Balipo granite （154±1 Ma）, agree well with the Re-Os ages of molybdenite in the Jinduicheng molybdenum polymetallic deposit （139±3 Ma） and the Balipo molybdenum polymetallic deposit （156±2 Ma）, indicating that the emplacement of granite porphyries occurred between Late Jurassic and Early Cretaceous. Zircons granite from the Jinduicheng area give the εHf（t） values mainly ranging from -10 to -16, and -20 to -24, respectively, corresponding to two- stage model ages （tDM2： mainly focused on 1.86-2.0 Ga, and 2.2-2.6 Ga, respectively） of zircons of the granite from the Jinduicheng values. The ore-forming materials are mainly derived from crust, with minor mantle substances. Zircons of the granite from the Balipo area give εHf（t） values ranging from -18 to -20, -28 to -38, and -42 to -44, respectively, corresponding to two-stage model ages （tDM2： mainly focused on 1.88-3.0 Ga, and 3.2-3.90 Ga, respectively）. the εHf（t） values of the Jinduicheng porphyry more than that of the Balipo porphyry, and two-stage model ages （tDM2） less than that of the Balipo porphyry, shows that he source of the porphyries originated from ancient lower crustal materials in the Jinduicheng area, and mixed younger components, more younger components contributed for the source of the Jinduicheng porphyry.展开更多
There are a wide range of magmatism and mineralization in the Yunkai area of South China during the Late Yanshanian Period, including the newly discovered Michang, Youmapo, Sanchaehong and Songwang porphyry-skarn W-Mo...There are a wide range of magmatism and mineralization in the Yunkai area of South China during the Late Yanshanian Period, including the newly discovered Michang, Youmapo, Sanchaehong and Songwang porphyry-skarn W-Mo deposits. In this study, we obtained zircon U-Pb ages of the ore-bearing biotite granites and their mafic enclaves from 884-1 to 1104-1 Ma. Zircons from the granites show Hf isotopic compositions with negative C-Hf（t） values of -5.9 to -0.6 and calculated Hf model ages （TvM2） of 1.5-1.2 Ga; indicating that the Middle Proterozoic crustal materials may have provided an important source for the magmatic rocks in this district during the Late Yanshanian Period, whereas zircons from the mafic enclaves show positive era（t） values of 1.3 to 10.1 with younger Hf model ages （TDM2） of 0.5-1.1 Ga, suggesting a mantle component may have involved in the granitic magma generation. Sulfur isotope study of the sulfide minerals from the W-Mo deposits show a narrow 834S distribution with most data ranging from -4.2%0 to 5.2‰. In addition, this study reports the first Fe isotopic compositions of pyrite in the W-Mo deposits, which show a uniform distribution range with the values near zero （656Fe=0.16‰-0.58‰, average 0.35‰; 657Fe=0.02‰-0.54‰, average 0.48‰）. These data indicate that the ore-forming materials may come from the deep-sourced granitic magma, and the mineralizations show a close relationship with the granitic magmatism during the Late Yanshanian Period. Combining with previous results, we suggest that there is a widespread porphyry-skarn W-Mo mineralization in the Yunkai area during the Late Cretaceous （80-110 Ma）, which has a close relationship with the Late Yanshanian magmatism that may have formed during the rollback of the subducted Pacific Plate.展开更多
A method was developed for the rapid in situ analysis of major and trace elements and Pb isotopes in silicate glass samples that combines laser ablation quadrupole and multi-collector inductively coupled plasma mass s...A method was developed for the rapid in situ analysis of major and trace elements and Pb isotopes in silicate glass samples that combines laser ablation quadrupole and multi-collector inductively coupled plasma mass spectrometry（LA-Q-ICP-MS/MC-ICP-MS）. Major, trace elements, and Pb isotope ratio compositions were clearly affected by laser conditions. Using a laser spot size of 160 μm, a laser ablation frequency of 15 Hz, an energy density 18 J/cm^2, and a 1 ： 9 ratio of laser ablation aerosol to the corresponding makeup gas, we obtained accurate major and trace element contents and Pb isotope ratios. Using Ca as the internal standard element, and GSE-1G and NIST 610 as the external standards for calibration, element contents generally matched the preferred values within 15%. Higher relative errors for some elements（e.g., Cr, Ga, Ge） may have been caused by lower than recommended values in some standards. The exponential law correction method for Tl normalization, with optimum adjusted Tl ratio, was utilized to obtain Pb isotopic data with good precision and accuracy. Pb isotopic ratios of the glass reference materials were in good agreement with the reference or published values to within 2 s measurement uncertainties, and the analytical precision was better than 0.17%（e.g., ^（208）Pb/^（206）Pb）. The developed method is a simple, reliable, and accurate technique for determining major, trace elements, and Pb isotope compositions of silicate glasses and minerals within a single ablation event.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(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 Open Fund Project of the Key Laboratory of Ionic Rare Earth Resources and Environment,Ministry of Natural Resources(Grant No.2022IREE101)the Young Elite Scientists Sponsorship Program by CAST(Grant No.2022QNRC001)the Geological Investigation Project(Grant Nos.DD20243483,DD20221643).
文摘The pervasively distributed granitoids in South China contributed greatly to regional polymetallic mineralization,including tungsten,tin,copper,gold,rare metals,and rare earth elements(REEs).To ascertain the dynamic backgrounds,rock types and genesis of the parent rocks related to the Early-Middle Jurassic ionic rare earth mineralization,typical deposits at Muzishan,Xiahu,and Zudong were investigated by conducting petrographic,geochronologic,whole-rock geochemical,and Sr-Nd-Pb isotope analyses,which found that the parent rocks from the Muzishan deposit were the A1-type K-feldspar granite(~195 Ma),from the Zudong deposit were the A2-type monzogranite(~171 Ma),and from the Xiahu deposit were the I-type monzogranite(~167 Ma).All the three granitic rocks underwent different degrees of fractionation,with the Xiahu granite experiencing the highest degree,followed by the Zudong granite,and the Muzishan granite undergoing the lowest degree.The Muzishan granite was concluded to be formed under an intraplate extensional tectonic regime influenced by the hotspots or the mantle plume.The Zudong granite was formed in a post-arc extensional setting related to subduction-collision-rollback of the paleo-Pacific Plate,which caused upwelling of the asthenosphere,thinning of the lithosphere,and partial melting of crustal materials.The Xiahu granite was generated under a transitional tectonic setting of extension and compression,triggered by delamination and rollback of the paleo-Pacific Plate.
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supported by the National Natural Science Foundation of China(Nos.42072069,41403023)China Geological Survey(No.1212011121270)the Natural Science Foundation of Hainan Province(Nos.521QN274 and 421CXTD441).
文摘Permian—Triassic granitoids are widely distributed along the Jinshajiang suture belt,eastern Xizang,and are regarded as the result of the tectonic-magmatic activity associated with the evolution of Paleo-Tethys Ocean.This paper focuses on the high-K calc-alkaline I-type Rennong(~235 Ma)and Jiaduoling(~232 Ma)granitoid plutons,eastern Xizang,which are enriched in light rare earth elements(LREEs)and large ion lithophile elements(LILEs),but depleted in high field strength elements(HFSEs)with moderate-weak negative Eu anomalies(0.61–0.90).The Rennong granites are characterized by uniform zircon ε_(Hf)(t)values(-7.3 to-3.5)and negative ε_(Nd)(t)values(-7.6 to-5.7),with old two-stage Nd model ages(T_(DM2)=1.51-1.46 Ga)and was likely formed by partial melting of the basement rocks,whereas the Jiaduoling rock samples have variable zircon ε_(Hf)(t)values(-5.7 to+5.5)but negativeεNd(t)values(-7.6 to-7.7)and are proposed to be formed by hybridization of mantle-derived mafic magma,Rennong felsic magma and sediments.Mafic microgranular enclaves(MMEs)in the Jiaduoling granitic rocks,have similar zircon U-Pb ages(~237 Ma)and zircon ε_(Hf)(t)values(-4.4 to+6.3)to the host rocks,indicating that zircons in the MMEs were actually xenocrysts that formed at an early stage in the granitic magma chamber.These results reveal that the break-off of the Jinshajiang oceanic slab beneath Changdu(Qamdo)-Simao Block was in a post-collisional setting,resulted in the upwelling of asthenosphere in the Late Triassic,and then,generated the wide-spread intermediate-felsic magmatism along the Jinshajing belt,including the Rennong and Jiaduoling plutons.
基金supported by the Geological Exploration Project Fund of Shandong Province([2018]19,[2019]54,[2021]1,[2022]6).
文摘The lithospheric thinning and huge gold mineralization in the Jiaodong Peninsula is intensively studied,aiming to better understand the geodynamic setting of the magmatic petrogenesis and the relationship between magmatism and large-scale mineralization.Thus,we conducted detailed research on the Weideshan intrusions in the Jiaodong region,including fi eld investigations,geochemical,geochronological and Hf isotope analysis,to reveal the tectonic implications for the destruction of the eastern North China Craton(NCC).The Weideshan intrusions consist of quartz monzodiorite,quartz monzonite and monzogranite.The SHRIMP zircon U-Pb dating results show that the Weideshan intrusions are emplaced at 115–112 Ma,namely,in the late Early Cretaceous period.Rocks of Weideshan intrusions are high-K calc-alkaline series and metaluminous granites.The trace elements are characterized by enrichment of Rb,Ba,Sr and LREE,with unobvious Eu anomalies and depletion of Nb,Ta,Zr,Hf and Ti.The contents of Ba and Sr are(913.00–1562.00)/1199.29μg/g and(373.00–793.00)/536.71μg/g,respectively,showing the features of high Ba–Sr granites(HBS).Development of numerous dark enclaves and negativeεHf(t)values(−17.93 to−12.19)indicate that the Weideshan granites originate from the mixture of crustal-derived felsic magma from partial melting of the Paleoproterozoic crust and alkali-rich magma from the enriched mantle.The generation of the Weideshan granites was closely related to the asthenospheric upwelling during the lithosphere thinning of the NCC in the late Mesozoic.
基金supported by the National Natural Science Foundation of China(No.92162103)the Natural Science Foundation of Hunan Province(No.2022JJ30699,No.2023JJ10064)the Science and Technology Innovation Program of Hunan Province(No.2021RC4055,No.2022RC1182).
文摘The Arabian-Nubian Shield(ANS)serves as a key geological archive,preserving the tectono-thermal evolution associated with the Rodinia breakup(∼900–800 Ma)and Gondwana formation(∼800–620 Ma).The Katherina Ring Complex(KRC),located in the Sinai Peninsula,Egypt(northern ANS),exemplifies continental growth through multistage magmatism and orogenesis,spanning the Tonian to Ediacaran periods(∼900–530 Ma).Despite its importance,debates persist regarding the nature,age,crustal characteristics,and magma source evolution of its constituent units.Situated in the northwestern part of the KRC,the Wadi Rofaiyed Cu deposit offers an exceptional natural laboratory for investigating continental crust formation during this interval,owing to its superb exposure and preservation.This study integrates detailed fieldwork,petrographic analyses,whole-rock geochemistry,Sr-Nd isotopes,and in situ zircon U-Pb-Lu-Hf isotopic data.It aims to(i)establish a robust chronological framework for the unmetamorphosed plutonic rocks of the KRC,(ii)advance the understanding of associated geodynamic processes,and(iii)elucidate the episodic magmatism events.The findings show that Wadi Rofaiyed juvenile crust developed in four main phases:(i)a subduction-accretionary phase(∼755 Ma)characterized by intense calc-alkaline magmatism,originating from the partial melting of mafic lower crust;(ii)a syn-collisional phase(∼630 Ma)occurred during the collision between the Saharan metacraton and the younger ANS crust,producing I-type granitoids formed through magma mixing and crustal anatexis;(iii)a post-collisional phase characterized by intermediate I-type(∼595 Ma)to felsic A-type alkaline magma(∼594 Ma),originated from the partial melting of the overthickened lower crust corresponding to lithospheric delamination;and(iv)an anorogenic phase(∼530 Ma)related to the final amalgamation of Greater Gondwana.Isotopic analyses across all four magmatic phases reveal low initial^(87)Sr/^(86)Sr(0.702648–0.703311)and positiveε_(Hf)(t)(+2.84 to+7.78)andε_(Nd)(t)(+2.61 to+5.21)values,consistent with lower crustal sources with depleted mantle-like signatures.The model ages(T_(DM2))for these magmatic rocks derived from zircon Hf(1.2–1.5 Ga)and whole-rock Nd isotopes(0.96–1.17 Ga)support a predominantly juvenile crustal origin.These findings underscore the multistage tectono-magmatic evolution of the northern ANS,advancing our understanding of obduction-accretion dynamics and crustal development during the Neoproterozoic.
基金funded by the Program of Science and Technology Department of Jiangxi Province(2023KDG01002 and 2023KDG01003)the National Natural Science Foundation of China(42062006 and 41962007)+1 种基金the Key Research and Development Program of Jiangxi Province(20223BBG71015)the Personnel Training Project of Jiangxi Bureau of Geology(2023JXDZKJRC02,2022JXDZKJRC04,and 2024JXDZKJRC05).
文摘The Tong’an-Baishuidong mining district(TBMD),located in the eastern section of the Jiangnan Orogen,is a newly discovered granite-type lithium mining district.Thisstudy presents new monazite U-Pb chronological,whole-rock geochemical,and Nd-Pb isotopic data to reveal the petrogenesis and geodynamic setting of the Wutang granites in the TBMD.The monazite U-Pb age of 145.8±1.0 Ma indicates that the granites were emplaced at the end of the Late Jurassic.Whole-rock geochemical results demonstrate that the Wutang granites are enriched in SiO_(2)(72.80-73.40 wt%)but depleted in CaO(0.44-0.90 wt%)and MgO+TiO_(2)+TFeO(1.79-2.05 wt%).These granites exhibit negative Eu anomalies(δEu=0.3−0.4)and high aluminum saturation indexes(A/CNK=1.2−1.6),differentiation indexes(DI=90-92),and Rb/Sr ratios(4.7-8.1).They also have moderate Ba contents(239-278 ppm)and low Sr contents(52.7-82.0 ppm)as well as low Nb/Ta(2.2-5.3)and Zr/Hf(21.3-31.5)ratios.All these indicate that they are highly fractionated granites.Additionally,these granites contain 5-10 wt%muscovite but no hornblende,with calculated corundum contents of 2.3-5.5 wt%.They have low high-field strength element(HFSE)contents(Zr+Nb+Ce+Y=182-202 ppm)and zircon saturation temperatures(700-770℃),with Th and Y negatively linked with Rb.These petrographic and geochemi-cal features further reveal that the Wutang granites belong to highly fractionated S-type granites.TheεNd(t)values of these granites range from−9.03 to−8.23,corresponding to two-stage model ages(T DM2)of 1488-1553 Ma.The initial Pb isotope ratios are:(206 Pb/^(204)Pb)i=18.38-18.55,(^(207)Pb/^(204)Pb)i=15.67-15.68,and(^(208)Pb/^(204)Pb)i=38.62-38.67.These Nd-Pb isotopic results demonstrate that the parental magma originated from the partial melting of ancient crustal materials.In the meantime,the TBMD in the eastern section of the Jiangnan Orogen was in a compression-extension transitional setting associated with the episodic subduction of the Paleo-Pacific Plate.
基金supported by the Natural Science Foundation of Jilin Province of China(grant no.20230101075JC)the National Natural Science Foundation of China(grant no.42072085).
文摘The deep geologic processes between the Xing’an-Mongolian Orogenic Belt and the North China Craton in the Mesozoic are crucial to reveal the magmatic and tectonic evolution and their constraints on mineralization in the Jiapigou-Haigou collage zone.In this paper,We have presented the geochronology,geochemistry and Sr-Nd-Hf isotopic compositions of the Middle Jurassic granitic complexes in the Songjianghe area,Jilin Province.The granitic complexes can be categorized into four groups based on their geologic characteristics,with corresponding zircon U-Pb isotope ages of 177 Ma,172 Ma,169 Ma and 168-167 Ma,respectively.These granitoids exhibit calcalkaline to high-K calc-alkaline,metaluminous to weakly peraluminous Ⅰ-type characteristics,which show relative enrichment in LILEs(Rb,Sr,Ba)and depletion in HFSEs(Nb,Zr).Geochemical analyses reveal high initial^(87)Sr/^(86)Sr ratios of 0.70633-0.70740,coupled with lowεNd(t)values ranging from−10.65 to−13.23.The zircon analyses show similarly negativeεHf(t)values ranging from−16.9 to−3.2.The integrated elemental and Hf-Sr-Nd isotopic signatures demonstrate that the primitive magmas of the four group rocks were primarily derived from partial melting of thickened Archean lower crust,with the exception of the Group Ⅳ rocks,which exhibit significant evidence of crustal contamination.The residual mineral assemblages during the magma-forming process varied from amphibole to eclogite facies.These findings indicate that magmatism in the Songjianghe region likely resulted from the accretion and delamination of the Archean crust in the collage zone during the subduction of the Paleo-Pacific Plate beneath the Eurasian continent.
基金funded via an Australian Geophysical Observing System grant provided to Au Scope Pty Ltd.the AQ44 Australian Education Investment Fund programpartly funded by the Western Australian Exploration Incentive Scheme
文摘Detrital zircon U-Pb geochronology has become the gold standard in evaluating source to sink relationships in sedimentary basins. However, the physical and chemical robustness of zircon, which make it such a useful mineral for provenance studies, is also a hindrance as zircon can be recycled through numerous sedimentary basins, thus obscuring the first cycle source to sink relationship. An elegant approach to addressing this potential issue is to compare the Pb isotope composition of detrital K-feldspar, a mineral which is unlikely to survive more than one erosion-transport-deposition cycle, with that of magmatic K-feldspar from potential basement source terranes. Here we present new in situ Pb isotope data on detrital K-feldspar from two Proterozoic arkosic sandstones from Western Australia, and magmatic K-feldspar grains from potential igneous source rocks, as inferred by the age and Hf isotope composition of detrital zircon grains. The data indicate that the detrital zircon and K-feldspar grains could not have been liberated from the same source rocks, and that the zircon has most likely been recycled through older sedimentary basins. These results provide a more complete understanding of apparently simple source to sink relationships in this part of Proterozoic Western Australia.
基金supported by the Basic Research Project for the Central Public Welfare Scientific Institutions(K1019) granted by the Institute of Mineral Resources,Chinese Academy of Geological Sciencesthe ministry of land and resources public welfare industry research project of China (200911007-6)the national crisis's mine resources prospecting project of China (20089949)
文摘The Mesozoic porphyry assemblage in the Jinduicheng area is a special molybdenum area in China, the Mo deposits, including the Jinduicheng, Balipo, Shijiawan, Huanglongpu, are distributed. The emplacement age and geochemical features of the granites in the Jinduicheng area can provide essential information for the exploration and development of the porphyry molybdenum deposit. In this study, we report LA-ICP-MS zircon U-Pb age and zircon Hf isotopic compositions of granite porphyries from the Jinduicheng area, and provide insights on the petrogensis and source characteristics of the granites. The results show that the zircon U-Pb ages of the Jinduicheng granite porphyry （143±1 Ma） and the Balipo granite （154±1 Ma）, agree well with the Re-Os ages of molybdenite in the Jinduicheng molybdenum polymetallic deposit （139±3 Ma） and the Balipo molybdenum polymetallic deposit （156±2 Ma）, indicating that the emplacement of granite porphyries occurred between Late Jurassic and Early Cretaceous. Zircons granite from the Jinduicheng area give the εHf（t） values mainly ranging from -10 to -16, and -20 to -24, respectively, corresponding to two- stage model ages （tDM2： mainly focused on 1.86-2.0 Ga, and 2.2-2.6 Ga, respectively） of zircons of the granite from the Jinduicheng values. The ore-forming materials are mainly derived from crust, with minor mantle substances. Zircons of the granite from the Balipo area give εHf（t） values ranging from -18 to -20, -28 to -38, and -42 to -44, respectively, corresponding to two-stage model ages （tDM2： mainly focused on 1.88-3.0 Ga, and 3.2-3.90 Ga, respectively）. the εHf（t） values of the Jinduicheng porphyry more than that of the Balipo porphyry, and two-stage model ages （tDM2） less than that of the Balipo porphyry, shows that he source of the porphyries originated from ancient lower crustal materials in the Jinduicheng area, and mixed younger components, more younger components contributed for the source of the Jinduicheng porphyry.
基金supported by the Fundamental Research Funds for the Central Universities (No. CUG120702)
文摘There are a wide range of magmatism and mineralization in the Yunkai area of South China during the Late Yanshanian Period, including the newly discovered Michang, Youmapo, Sanchaehong and Songwang porphyry-skarn W-Mo deposits. In this study, we obtained zircon U-Pb ages of the ore-bearing biotite granites and their mafic enclaves from 884-1 to 1104-1 Ma. Zircons from the granites show Hf isotopic compositions with negative C-Hf（t） values of -5.9 to -0.6 and calculated Hf model ages （TvM2） of 1.5-1.2 Ga; indicating that the Middle Proterozoic crustal materials may have provided an important source for the magmatic rocks in this district during the Late Yanshanian Period, whereas zircons from the mafic enclaves show positive era（t） values of 1.3 to 10.1 with younger Hf model ages （TDM2） of 0.5-1.1 Ga, suggesting a mantle component may have involved in the granitic magma generation. Sulfur isotope study of the sulfide minerals from the W-Mo deposits show a narrow 834S distribution with most data ranging from -4.2%0 to 5.2‰. In addition, this study reports the first Fe isotopic compositions of pyrite in the W-Mo deposits, which show a uniform distribution range with the values near zero （656Fe=0.16‰-0.58‰, average 0.35‰; 657Fe=0.02‰-0.54‰, average 0.48‰）. These data indicate that the ore-forming materials may come from the deep-sourced granitic magma, and the mineralizations show a close relationship with the granitic magmatism during the Late Yanshanian Period. Combining with previous results, we suggest that there is a widespread porphyry-skarn W-Mo mineralization in the Yunkai area during the Late Cretaceous （80-110 Ma）, which has a close relationship with the Late Yanshanian magmatism that may have formed during the rollback of the subducted Pacific Plate.
基金supported by the National Natural Science Foundation of China (Nos.41427804,41421002,41373004)the Beijing SHRIMP Center Open Foundation+1 种基金the Program for Changjiang Scholars and Innovative Research Team in China Universities (No.IRT1281)the MOST Research Foundation from the State Key Laboratory of Continental Dynamics,Northwest University,Xi’an,China (Nos.BJ08132-1,201210006)
文摘A method was developed for the rapid in situ analysis of major and trace elements and Pb isotopes in silicate glass samples that combines laser ablation quadrupole and multi-collector inductively coupled plasma mass spectrometry（LA-Q-ICP-MS/MC-ICP-MS）. Major, trace elements, and Pb isotope ratio compositions were clearly affected by laser conditions. Using a laser spot size of 160 μm, a laser ablation frequency of 15 Hz, an energy density 18 J/cm^2, and a 1 ： 9 ratio of laser ablation aerosol to the corresponding makeup gas, we obtained accurate major and trace element contents and Pb isotope ratios. Using Ca as the internal standard element, and GSE-1G and NIST 610 as the external standards for calibration, element contents generally matched the preferred values within 15%. Higher relative errors for some elements（e.g., Cr, Ga, Ge） may have been caused by lower than recommended values in some standards. The exponential law correction method for Tl normalization, with optimum adjusted Tl ratio, was utilized to obtain Pb isotopic data with good precision and accuracy. Pb isotopic ratios of the glass reference materials were in good agreement with the reference or published values to within 2 s measurement uncertainties, and the analytical precision was better than 0.17%（e.g., ^（208）Pb/^（206）Pb）. The developed method is a simple, reliable, and accurate technique for determining major, trace elements, and Pb isotope compositions of silicate glasses and minerals within a single ablation event.
