The Jiajika granitic-and pegmatite-type lithium deposit,which is in the Songpan-Garze Orogenic Belt in western Sichuan Province,China,is the largest in Asia.Previous studies have examined the geochemistry and mineralo...The Jiajika granitic-and pegmatite-type lithium deposit,which is in the Songpan-Garze Orogenic Belt in western Sichuan Province,China,is the largest in Asia.Previous studies have examined the geochemistry and mineralogy of pegmatites and their parental source rocks to determine the genesis of the deposit.However,the evolution of magmatic-hydrothermal fluids has received limited attention.We analyzed He–Ar–H–O isotopes to decipher the ore-fluid nature and identify the contribution of fluids to mineralization in the late stage of crystallization differentiation.In the Jiajika ore field,two-mica granites,pegmatites(including common pegmatites and spodumene pegmatites),metasandstones,and schists are the dominant rock types exposed.Common pegmatites derived from early differentiation of the two-mica granitic magmas before they evolved into spodumene pegmatites during the late stage of the magmatic evolution.Common pegmatites have~3He/~4He ratios that vary from 0.18 to 4.68 Ra(mean1.62 Ra),and their~(40)Ar/~(36)Ar ratios range from 426.70 to 1408.06(mean 761.81);spodumene pegmatites have~3He/~4He ratios that vary from 0.18 to 2.66 Ra(mean 0.87Ra)and their~(40)Ar/~(36)Ar ratios range from 402.13 to 1907.34(mean 801.65).These data indicate that the hydrothermal fluids were shown a mixture of crust-and mantle-derived materials,and the proportion of crustderived materials in spodumene pegmatites increases significantly in the late stage of the magmatic evolution.Theδ~(18)OH_(2)O–VSMOWvalues of common pegmatites range from 6.2‰to 10.9‰,with a mean value of 8.6‰,andδDV–SMOWvalues vary from-110‰to-72‰,with a mean o f-85‰.Theδ~(18)OH_(2)O–VSMOWvalues of spodumene pegmatites range from 5.3‰to 13.2‰,with a mean of 9.1‰,andδDV–SMOWvalues vary from-115‰to-77‰,with a mean of-91‰.These data suggest that the ore-forming fluids came from primary magmatic water gradually mixing with more meteoric water in the late stage of the magmatic evolution.Based on the He–Ar–H–O and other existing data,we propose that the oreforming metals are mainly derived from the upper continental crust with a minor contribution from the mantle,and the fluid exsolution and addition of meteoric water during the formation of pegmatite contributed to the formation of the Jiajika superlarge lithium deposit.展开更多
The Merguechoum fluorite-barite mineralization,located in the Eastern Meseta of Morocco,is hosted in the Late Hercynian granite.The ore consists of fine crystals of fluorite 1,massive barite 1,euhedral crystals of flu...The Merguechoum fluorite-barite mineralization,located in the Eastern Meseta of Morocco,is hosted in the Late Hercynian granite.The ore consists of fine crystals of fluorite 1,massive barite 1,euhedral crystals of fluorite 2,and barite 2 with calcite and minor quartz and sulfides.The Merguechoum ore deposits have never been investigated.This study was the first contribution that studied the genesis of fluorite and barite.The ore occurs as dissemination within granite intrusion and also fills the NE-SWtrending meter-sized fractures and faults.The values of the total Rare Earth Elements and Yttrium(REY)and the ratios of LREY/HREY,Y/Ho,Tb/Ca,and Tb/La indicate that the Merguechoum fluorite precipitated from hydrothermal fluids,likely basinal brines,which interacted with the Hercynian granite.The REY data indicate that the ore-forming fluids of the early stage have intensely interacted with the Hercynian granite compared to those of the late ore stage.The gradual decrease in the europium(Eu/Eu^(*)),yttrium(Y/Y^(*)),and cerium(Ce/Ce^(*))anomalies and a low concentration ofΣREY observed in the second ore stage compared to the first ore stage suggest an increase in p H and fO_(2)and by inference a decrease in temperature during the evolution of the hydrothermal system.This evolution could be explained by fluid mixing between the ascending basinal hydrothermal fluids and the diluted sulfate-rich meteoric water barite separates from selected samples reveal that the dissolved sulfates(SO_(4)^(2-))were derived from Permian–Triassic sulfates and/or coeval poreseawater sulfates.The proposed fluid mixing triggered the precipitation of an early-stage F-Ba assemblage followed by the second-stage F-Ba mineralization.Geologic fieldwork,REY inventories,and isotope data point to the ore genesis during the Permian–Triassic extensional tectonic activity concerning the Pangea rifting.This extensional tectonic environment is likely the driving force that mobilized a large amount of the ore-forming basinal brines along the available faults and fractures to the loci of ore deposition.展开更多
Geologic, petrographic and petrochemical studies of the late Mesozoic K-rich melanocratic dykes, including lamprophyres, andesite porphyrites and dacite-porphyry in the gold field system in the Jiaodong Peninsula, Chi...Geologic, petrographic and petrochemical studies of the late Mesozoic K-rich melanocratic dykes, including lamprophyres, andesite porphyrites and dacite-porphyry in the gold field system in the Jiaodong Peninsula, China, have shown that these dykes are characterized by rich potassium and alkali but poor titanium. They belong to an ultra-high potassic, shoshonitic and high potassic calc-alkaline rock series. The parental magma has relatively high initial strontium ratios ((87Sr/86Sr),=0.70895-0.71140) and low (143Nd/144Nd)1 ratios (varying from 0.51135 to 0.51231); and its δ18Osmow, whole rock values vary from +5.8%c to +10.6%c with a mean of +7.1%c. These features suggest that the source region of the magma is an enriched mantle wedge transformed from a continental lithosphere mantle which has experienced metasomatism by mantle-derived fluids with H2O-dominated fluids that were provided during the underthrusting of an ocean crust. The initial magma was generated by low-degree partial melting of the enriched mantle in its mature stage in the back-arc spreading environment. The evolution of magmas is associated with two trends, i.e., fractional crystallization and mixing with or intensive contamination by palaeo-crust materials or metamorphic rocks. The former process is evident in the gold field system of quartz-vein type, whereas the latter is dominated in the gold field system of the altered-rock type. This conclusion is very important for more detailed study of petrogenesis and mineralization through the crust-mantle interaction (exchange) in the Mesozoic in this region.展开更多
The Laojiezi alkaline volcanic rocks, which are located in the intraplate region of the Yangtze craton, coincide with the formation of the Jinshajiang-Ailaoshan-Red River alkaline rock belt. Although this belt has bee...The Laojiezi alkaline volcanic rocks, which are located in the intraplate region of the Yangtze craton, coincide with the formation of the Jinshajiang-Ailaoshan-Red River alkaline rock belt. Although this belt has been widely studied by geologists because of its porphyry-related Pb-Ag-Au polymetallic deposit and geotectonic location, the material sources of this belt are still debate. Whole-rock analyses show that these rocks have high total alkali contents(3.73–11.08 wt%), and their aluminum saturation index(ASI) values widely vary from 0.82 to 3.07, which comprise a metaluminous-peraluminous magma series. These rocks are characterized by high K(K2 O/Na2 O>1) and low Ti and Mg contents; enrichment in large-ion lithophile elements, such as Rb, Ba, K and light rare earth elements; and depletion in high field strength elements, such as Ta, Nb, P, and Ti. These rocks exhibit moderate Eu(Eu/Eu*=0.86–1.04) and Ce(Ce/Ce*=0.63–0.96) anomalies. Their(87 Sr/86 Sr)i, εNd(t), zircon εHf(t) and δ18 O values range from 0.70839 to 0.71013, from-10.16 to-12.45, from-19.6 to-5.8, and from 5.69‰ to 8.54‰, respectively, and their Nd and Hf two-stage model ages(TDM2) are 1.67–1.86 Ga and 1.27–2.02 Ga, respectively. These data reflect the primary partial melting of Paleoproterozoic to Mesoproterozoic lower crust with minor residual continental lithospheric mantle and supracrustal metasediments. The lithosphere was likely thickened along the southeastern margin of the Tibetan Plateau following the Indian-Asian continentcontinent collision(65–41 Ma). During the post-collision phase(36–16 Ma), the transition from a compressional to extensional setting triggered the convective removal of the over-thickened CLM beneath the Yangtze craton, which led to the upwelling of asthenospheric materials. This process created alkali-rich and high-K magma through the partial melting of the thickened lower crust. Magma that carried Cu-Au-Pb-Ag minerals was emplaced by strike-slip motion along the E-to W-or ENE-to WSWtrending tectonically weak zone, finally forming an alkaline porphyry Cu-Au-Pb-Ag polymetallic deposit.展开更多
Escherichia coli O157:H7 is one of the major foodborne pathogenic bacterial that cause infectious diseases in humans.The previous found that a combination of kojic acid and tea polyphenols exhibited better activity ag...Escherichia coli O157:H7 is one of the major foodborne pathogenic bacterial that cause infectious diseases in humans.The previous found that a combination of kojic acid and tea polyphenols exhibited better activity against E.coli O157:H7 than using either alone.This study aimed to explore responses underlying the antibacterial mechanisms of kojic acid and tea polyphenols from the gene level.The functional enrichment analysis by comparing kojic acid and tea polyphenols individually or synergistically against E.coli O157:H7 found that acid resistance systems in kojic acid were activated,and the cell membrane and genomic DNA were destructed in the cells,resulting in“oxygen starvation”.The oxidative stress response triggered by tea polyphenols inhibited both sulfur uptake and the synthesis of ATP,which affected the bacteria's life metabolic process.Interestingly,we found that kojic acid combined with tea polyphenols hindered the uptake of iron that played an essential role in the synthesis of DNA,respiration,tricarboxylic acid cycle.The results suggested that the iron uptake pathways may represent a novel approach for kojic acid and tea polyphenols synergistically against E.coli O157:H7 and provided a theoretical basis for bacterial pathogen control in the food industry.展开更多
The Banian sediment-hosted antimony deposit is a medium-scale deposit located in the Dushan County,South Guizhou,China.Calcite as the dominant gangue mineral can be divided into two types: white and pink,the later is ...The Banian sediment-hosted antimony deposit is a medium-scale deposit located in the Dushan County,South Guizhou,China.Calcite as the dominant gangue mineral can be divided into two types: white and pink,the later is more intimate with mineralization.It is interesting that the REE characteristics are展开更多
The isotope composition in precipitation has been widely considered as a tracer of monsoon activity.Compared with the coastal region,the monsoon margin usually has limited precipitation with large fluctuation and is u...The isotope composition in precipitation has been widely considered as a tracer of monsoon activity.Compared with the coastal region,the monsoon margin usually has limited precipitation with large fluctuation and is usually sensitive to climate change.The water resource management in the monsoon margin should be better planned by understanding the composition of precipitation isotope and its influencing factors.In this study,the precipitation samples were collected at five sampling sites(Baiyin City,Kongtong District,Maqu County,Wudu District,and Yinchuan City)of the monsoon margin in the northwest of China in 2022 to analyze the characteristics of stable hydrogen(δD)and oxygen(δ18O)isotopes.We analyzed the impact of meteorological factors(temperature,precipitation,and relative humidity)on the composition of precipitation isotope at daily level by regression analysis,utilized the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)-based backward trajectory model to simulate the air mass trajectory of precipitation events,and adopted the potential source contribution function(PSCF)and concentration weighted trajectory(CWT)to analyze the water vapor sources.The results showed that compared with the global meteoric water line(GMWL),the slope of the local meteoric water line(LMWL;δD=7.34δ^(18)O-1.16)was lower,indicating the existence of strong regional evaporation in the study area.Temperature significantly contributed toδ18O value,while relative humidity had a significant negative effect onδ18O value.Through the backward trajectory analysis,we found eight primary locations that were responsible for the water vapor sources of precipitation in the study area,of which moisture from the Indian Ocean to South China Sea(ITSC)and the western continental(CW)had the greatest influence on precipitation in the study area.The hydrogen and oxygen isotopes in precipitation are significantly influenced by the sources and transportation paths of air mass.In addition,the results of PSCF and CWT analysis showed that the water vapor source areas were primarily distributed in the south and northwest direction of the study area.展开更多
The dual isotopes(N and O)of nitrate were measured using a denitrifier bacterial method in the western South China Sea(WSCS)during September 2015 to elucidate key information during N transformation in the lower eupho...The dual isotopes(N and O)of nitrate were measured using a denitrifier bacterial method in the western South China Sea(WSCS)during September 2015 to elucidate key information during N transformation in the lower euphotic zone(LEZ)-upper mesopelagic zone(UMZ,down to 500 m in this study)continuum,which is a vital sub-environment for marine N cycle and sequestration of atmospheric CO_(2)as well.The N isotopic composition(δ^(15)N)of nitrate generally decreased from 500 m toward the base of the euphotic zone(∼100 m),reaching a value of∼4.6‰(vs.air N_(2))at the base of the LEZ,suggesting the imprint of remineralization(nitrification)of isotopically light N from atmospheric source.Theδ^(15)N andδ18O of nitrate only generally conform to a 1:1 line at 50 m and 75 m,suggesting that nitrate assimilation is a dominant process to shape nitrate isotope signature in this light-limited and relatively N-replete lower part of the euphotic zone.The fractionation factors of N and O isotopes during nitrate fractionation(15εASSIM,18εASSIM)using a steady-state model were estimated to be 4.0‰±0.3‰and 5.4‰±0.3‰,respectively.The occurrence of nitrification at the base of the LEZ and most of the UMZ is corroborated by the decoupling ofδ^(15)N and the oxygen isotopic composition(δ18O)of nitrate.Our results will provide insights for better understanding N cycle in the South China Sea from a perspective of present and past.展开更多
The Nanyangtian skarn-type scheelite deposit is an important part of the Laojunshan W–Sn polymetallic metallogenic region in southeastern Yunnan Province,China. The deposit comprises multiple scheelite ore bodies;mul...The Nanyangtian skarn-type scheelite deposit is an important part of the Laojunshan W–Sn polymetallic metallogenic region in southeastern Yunnan Province,China. The deposit comprises multiple scheelite ore bodies;multilayer skarn-type scheelite ore bodies are dominant,with a small amount of quartz vein-type ore bodies. Skarn minerals include diopside, hedenbergite, grossular, and epidote. Three mineralization stages exist: skarn, quartz–scheelite, and calcite. The homogenization temperatures of fluid inclusions in hydrothermal minerals that formed in different paragenetic phases were measured as follows:221–423℃ (early skarn stage), 177–260℃ (quartz–scheelite stage), and 173–227℃ (late calcite stage). The measured salinity of fluid inclusions ranged from 0.18% to16.34% NaCleqv(skarn stage), 0.35%–7.17% NaCleqv(quartz–scheelite stage), and 0.35%–2.24% NaCleqv(late calcite vein stage). Laser Raman spectroscopic studies on fluid inclusions in the three stages showed H_2O as the main component, with N_2 present in minor amounts. Minor amounts of CH_4 were found in the quartz–scheelite stage. It was observed that the homogenization temperature gradually reduced from the early to the late mineralization stages; moreover, δ^(13)C_(PDB) values for ore-bearing skarn in the mineralization period ranged from -5.7‰ to-6.9‰ and the corresponding δ^(18)O_(SMOW) values ranged from 5.8‰ to 9.1‰, implying that the ore-forming fluid was mainly sourced from magmatic water with a minor amount of meteoric water. Collectively, the evidence indicates that the formation of the Nanyangtian deposit is related to Laojunshan granitic magmatism.展开更多
The Pb-Zn metallogenic district in NW Guizhou Province is an important part of the Yun-nan-Sichuan-Guizhou Pb-Zn metallogenic province, and also is one of the most important Pb-Zn producers in China. The hosting rocks...The Pb-Zn metallogenic district in NW Guizhou Province is an important part of the Yun-nan-Sichuan-Guizhou Pb-Zn metallogenic province, and also is one of the most important Pb-Zn producers in China. The hosting rocks of the Pb-Zn deposits are Devonian to Permian carbonate rocks, and the basement rocks are meta-sedimentary and igneous rocks of the Proterozoic Kunyang and Huili groups. The ore minerals are composed of sphalerite, galena and pyrite, and the gangue minerals are include calcite and dolomite. Geology and C-O isotope of these deposits were studied in this paper. The results show that δ13C and δ18O values of hydrothermal calcite, altered wall rocks-dolostone, sedimentary calcite and hosting carbonate rocks range from -5.3‰ to -0.6 ‰ (mean -3.4‰) and +11.3‰ to +20.9 ‰ (mean +17.2‰), -3.0‰ to +0.9 ‰ (mean -1.3‰) and +17.0‰ to +20.8‰ (mean +19.7‰), +0.6‰ to +2.5 ‰ (mean +1.4‰) and +23.4‰ to +26.5 ‰ (mean +24.6‰), and -1.8‰ to +3.9‰ (mean +0.7‰) and +21.0‰ to +26.8‰ (mean +22.9‰), respectively, implying that CO2 in the ore-forming fluids was mainly a result of dissolution of Devonian and Carboniferous carbonate rocks. However, it is difficult to evaluate the contribution of sediment de-hydroxylation. Based on the integrated analysis of geology, C and O isotopes, it is believed that the ore-forming fluids of these carbonate-hosted Pb-Zn deposits in this area were derived from multiple sources, including hosting carbonate rocks, Devonian to Permian sedimentary rocks and basement rocks (the Kun-yang and Huili groups). Therefore, the fluids mixing is the main precipitation mechanism of the Pb-Zn deposit in this province.展开更多
基金financially supported by grants from the National Key Research and Development Project of China(2021YFC2901903 and 2017YFC0602705)the Jiangxi Province(2020101003)the East China University of Technology(1410000874)。
文摘The Jiajika granitic-and pegmatite-type lithium deposit,which is in the Songpan-Garze Orogenic Belt in western Sichuan Province,China,is the largest in Asia.Previous studies have examined the geochemistry and mineralogy of pegmatites and their parental source rocks to determine the genesis of the deposit.However,the evolution of magmatic-hydrothermal fluids has received limited attention.We analyzed He–Ar–H–O isotopes to decipher the ore-fluid nature and identify the contribution of fluids to mineralization in the late stage of crystallization differentiation.In the Jiajika ore field,two-mica granites,pegmatites(including common pegmatites and spodumene pegmatites),metasandstones,and schists are the dominant rock types exposed.Common pegmatites derived from early differentiation of the two-mica granitic magmas before they evolved into spodumene pegmatites during the late stage of the magmatic evolution.Common pegmatites have~3He/~4He ratios that vary from 0.18 to 4.68 Ra(mean1.62 Ra),and their~(40)Ar/~(36)Ar ratios range from 426.70 to 1408.06(mean 761.81);spodumene pegmatites have~3He/~4He ratios that vary from 0.18 to 2.66 Ra(mean 0.87Ra)and their~(40)Ar/~(36)Ar ratios range from 402.13 to 1907.34(mean 801.65).These data indicate that the hydrothermal fluids were shown a mixture of crust-and mantle-derived materials,and the proportion of crustderived materials in spodumene pegmatites increases significantly in the late stage of the magmatic evolution.Theδ~(18)OH_(2)O–VSMOWvalues of common pegmatites range from 6.2‰to 10.9‰,with a mean value of 8.6‰,andδDV–SMOWvalues vary from-110‰to-72‰,with a mean o f-85‰.Theδ~(18)OH_(2)O–VSMOWvalues of spodumene pegmatites range from 5.3‰to 13.2‰,with a mean of 9.1‰,andδDV–SMOWvalues vary from-115‰to-77‰,with a mean of-91‰.These data suggest that the ore-forming fluids came from primary magmatic water gradually mixing with more meteoric water in the late stage of the magmatic evolution.Based on the He–Ar–H–O and other existing data,we propose that the oreforming metals are mainly derived from the upper continental crust with a minor contribution from the mantle,and the fluid exsolution and addition of meteoric water during the formation of pegmatite contributed to the formation of the Jiajika superlarge lithium deposit.
文摘The Merguechoum fluorite-barite mineralization,located in the Eastern Meseta of Morocco,is hosted in the Late Hercynian granite.The ore consists of fine crystals of fluorite 1,massive barite 1,euhedral crystals of fluorite 2,and barite 2 with calcite and minor quartz and sulfides.The Merguechoum ore deposits have never been investigated.This study was the first contribution that studied the genesis of fluorite and barite.The ore occurs as dissemination within granite intrusion and also fills the NE-SWtrending meter-sized fractures and faults.The values of the total Rare Earth Elements and Yttrium(REY)and the ratios of LREY/HREY,Y/Ho,Tb/Ca,and Tb/La indicate that the Merguechoum fluorite precipitated from hydrothermal fluids,likely basinal brines,which interacted with the Hercynian granite.The REY data indicate that the ore-forming fluids of the early stage have intensely interacted with the Hercynian granite compared to those of the late ore stage.The gradual decrease in the europium(Eu/Eu^(*)),yttrium(Y/Y^(*)),and cerium(Ce/Ce^(*))anomalies and a low concentration ofΣREY observed in the second ore stage compared to the first ore stage suggest an increase in p H and fO_(2)and by inference a decrease in temperature during the evolution of the hydrothermal system.This evolution could be explained by fluid mixing between the ascending basinal hydrothermal fluids and the diluted sulfate-rich meteoric water barite separates from selected samples reveal that the dissolved sulfates(SO_(4)^(2-))were derived from Permian–Triassic sulfates and/or coeval poreseawater sulfates.The proposed fluid mixing triggered the precipitation of an early-stage F-Ba assemblage followed by the second-stage F-Ba mineralization.Geologic fieldwork,REY inventories,and isotope data point to the ore genesis during the Permian–Triassic extensional tectonic activity concerning the Pangea rifting.This extensional tectonic environment is likely the driving force that mobilized a large amount of the ore-forming basinal brines along the available faults and fractures to the loci of ore deposition.
文摘Geologic, petrographic and petrochemical studies of the late Mesozoic K-rich melanocratic dykes, including lamprophyres, andesite porphyrites and dacite-porphyry in the gold field system in the Jiaodong Peninsula, China, have shown that these dykes are characterized by rich potassium and alkali but poor titanium. They belong to an ultra-high potassic, shoshonitic and high potassic calc-alkaline rock series. The parental magma has relatively high initial strontium ratios ((87Sr/86Sr),=0.70895-0.71140) and low (143Nd/144Nd)1 ratios (varying from 0.51135 to 0.51231); and its δ18Osmow, whole rock values vary from +5.8%c to +10.6%c with a mean of +7.1%c. These features suggest that the source region of the magma is an enriched mantle wedge transformed from a continental lithosphere mantle which has experienced metasomatism by mantle-derived fluids with H2O-dominated fluids that were provided during the underthrusting of an ocean crust. The initial magma was generated by low-degree partial melting of the enriched mantle in its mature stage in the back-arc spreading environment. The evolution of magmas is associated with two trends, i.e., fractional crystallization and mixing with or intensive contamination by palaeo-crust materials or metamorphic rocks. The former process is evident in the gold field system of quartz-vein type, whereas the latter is dominated in the gold field system of the altered-rock type. This conclusion is very important for more detailed study of petrogenesis and mineralization through the crust-mantle interaction (exchange) in the Mesozoic in this region.
基金funded by the Open Foundation of the Beijing SHRIMP Center (DDC15-016)the Applied Basic Research Program Youth Project of Yunnan Province (2016DF031)the National Basic Research Program of China (2015CB452605)
文摘The Laojiezi alkaline volcanic rocks, which are located in the intraplate region of the Yangtze craton, coincide with the formation of the Jinshajiang-Ailaoshan-Red River alkaline rock belt. Although this belt has been widely studied by geologists because of its porphyry-related Pb-Ag-Au polymetallic deposit and geotectonic location, the material sources of this belt are still debate. Whole-rock analyses show that these rocks have high total alkali contents(3.73–11.08 wt%), and their aluminum saturation index(ASI) values widely vary from 0.82 to 3.07, which comprise a metaluminous-peraluminous magma series. These rocks are characterized by high K(K2 O/Na2 O>1) and low Ti and Mg contents; enrichment in large-ion lithophile elements, such as Rb, Ba, K and light rare earth elements; and depletion in high field strength elements, such as Ta, Nb, P, and Ti. These rocks exhibit moderate Eu(Eu/Eu*=0.86–1.04) and Ce(Ce/Ce*=0.63–0.96) anomalies. Their(87 Sr/86 Sr)i, εNd(t), zircon εHf(t) and δ18 O values range from 0.70839 to 0.71013, from-10.16 to-12.45, from-19.6 to-5.8, and from 5.69‰ to 8.54‰, respectively, and their Nd and Hf two-stage model ages(TDM2) are 1.67–1.86 Ga and 1.27–2.02 Ga, respectively. These data reflect the primary partial melting of Paleoproterozoic to Mesoproterozoic lower crust with minor residual continental lithospheric mantle and supracrustal metasediments. The lithosphere was likely thickened along the southeastern margin of the Tibetan Plateau following the Indian-Asian continentcontinent collision(65–41 Ma). During the post-collision phase(36–16 Ma), the transition from a compressional to extensional setting triggered the convective removal of the over-thickened CLM beneath the Yangtze craton, which led to the upwelling of asthenospheric materials. This process created alkali-rich and high-K magma through the partial melting of the thickened lower crust. Magma that carried Cu-Au-Pb-Ag minerals was emplaced by strike-slip motion along the E-to W-or ENE-to WSWtrending tectonically weak zone, finally forming an alkaline porphyry Cu-Au-Pb-Ag polymetallic deposit.
基金supported by National Natural Science Foundation of China(31972021)R&D Projects in Key Areas of Guangdong Province(2019B020212003)+4 种基金the Science and Technology Program of Guangzhou,China(202206010177)Guangdong key research and development program(2021B0202060001)Foshan and agricultural academy cooperation projectGuangdong Modern Agriculture project(2022KJ117)Aquatic Products Center Project of GAAS。
文摘Escherichia coli O157:H7 is one of the major foodborne pathogenic bacterial that cause infectious diseases in humans.The previous found that a combination of kojic acid and tea polyphenols exhibited better activity against E.coli O157:H7 than using either alone.This study aimed to explore responses underlying the antibacterial mechanisms of kojic acid and tea polyphenols from the gene level.The functional enrichment analysis by comparing kojic acid and tea polyphenols individually or synergistically against E.coli O157:H7 found that acid resistance systems in kojic acid were activated,and the cell membrane and genomic DNA were destructed in the cells,resulting in“oxygen starvation”.The oxidative stress response triggered by tea polyphenols inhibited both sulfur uptake and the synthesis of ATP,which affected the bacteria's life metabolic process.Interestingly,we found that kojic acid combined with tea polyphenols hindered the uptake of iron that played an essential role in the synthesis of DNA,respiration,tricarboxylic acid cycle.The results suggested that the iron uptake pathways may represent a novel approach for kojic acid and tea polyphenols synergistically against E.coli O157:H7 and provided a theoretical basis for bacterial pathogen control in the food industry.
文摘The Banian sediment-hosted antimony deposit is a medium-scale deposit located in the Dushan County,South Guizhou,China.Calcite as the dominant gangue mineral can be divided into two types: white and pink,the later is more intimate with mineralization.It is interesting that the REE characteristics are
基金supported by the National Natural Science Foundation of China(42161007)the Scientific Research Program for Higher Education Institutions of Gansu Province(2021B-081)the Natural Science Foundation of Gansu Province(22JR5RA074).
文摘The isotope composition in precipitation has been widely considered as a tracer of monsoon activity.Compared with the coastal region,the monsoon margin usually has limited precipitation with large fluctuation and is usually sensitive to climate change.The water resource management in the monsoon margin should be better planned by understanding the composition of precipitation isotope and its influencing factors.In this study,the precipitation samples were collected at five sampling sites(Baiyin City,Kongtong District,Maqu County,Wudu District,and Yinchuan City)of the monsoon margin in the northwest of China in 2022 to analyze the characteristics of stable hydrogen(δD)and oxygen(δ18O)isotopes.We analyzed the impact of meteorological factors(temperature,precipitation,and relative humidity)on the composition of precipitation isotope at daily level by regression analysis,utilized the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)-based backward trajectory model to simulate the air mass trajectory of precipitation events,and adopted the potential source contribution function(PSCF)and concentration weighted trajectory(CWT)to analyze the water vapor sources.The results showed that compared with the global meteoric water line(GMWL),the slope of the local meteoric water line(LMWL;δD=7.34δ^(18)O-1.16)was lower,indicating the existence of strong regional evaporation in the study area.Temperature significantly contributed toδ18O value,while relative humidity had a significant negative effect onδ18O value.Through the backward trajectory analysis,we found eight primary locations that were responsible for the water vapor sources of precipitation in the study area,of which moisture from the Indian Ocean to South China Sea(ITSC)and the western continental(CW)had the greatest influence on precipitation in the study area.The hydrogen and oxygen isotopes in precipitation are significantly influenced by the sources and transportation paths of air mass.In addition,the results of PSCF and CWT analysis showed that the water vapor source areas were primarily distributed in the south and northwest direction of the study area.
基金The National Natural Science Foundation of China under contract Nos 42076042 and 41721005the Science and Technology Basic Resources Investigation Program of China under contract No.2017FY201403.
文摘The dual isotopes(N and O)of nitrate were measured using a denitrifier bacterial method in the western South China Sea(WSCS)during September 2015 to elucidate key information during N transformation in the lower euphotic zone(LEZ)-upper mesopelagic zone(UMZ,down to 500 m in this study)continuum,which is a vital sub-environment for marine N cycle and sequestration of atmospheric CO_(2)as well.The N isotopic composition(δ^(15)N)of nitrate generally decreased from 500 m toward the base of the euphotic zone(∼100 m),reaching a value of∼4.6‰(vs.air N_(2))at the base of the LEZ,suggesting the imprint of remineralization(nitrification)of isotopically light N from atmospheric source.Theδ^(15)N andδ18O of nitrate only generally conform to a 1:1 line at 50 m and 75 m,suggesting that nitrate assimilation is a dominant process to shape nitrate isotope signature in this light-limited and relatively N-replete lower part of the euphotic zone.The fractionation factors of N and O isotopes during nitrate fractionation(15εASSIM,18εASSIM)using a steady-state model were estimated to be 4.0‰±0.3‰and 5.4‰±0.3‰,respectively.The occurrence of nitrification at the base of the LEZ and most of the UMZ is corroborated by the decoupling ofδ^(15)N and the oxygen isotopic composition(δ18O)of nitrate.Our results will provide insights for better understanding N cycle in the South China Sea from a perspective of present and past.
基金supported by the Natural Science Foundation of China (No.41373050)
文摘The Nanyangtian skarn-type scheelite deposit is an important part of the Laojunshan W–Sn polymetallic metallogenic region in southeastern Yunnan Province,China. The deposit comprises multiple scheelite ore bodies;multilayer skarn-type scheelite ore bodies are dominant,with a small amount of quartz vein-type ore bodies. Skarn minerals include diopside, hedenbergite, grossular, and epidote. Three mineralization stages exist: skarn, quartz–scheelite, and calcite. The homogenization temperatures of fluid inclusions in hydrothermal minerals that formed in different paragenetic phases were measured as follows:221–423℃ (early skarn stage), 177–260℃ (quartz–scheelite stage), and 173–227℃ (late calcite stage). The measured salinity of fluid inclusions ranged from 0.18% to16.34% NaCleqv(skarn stage), 0.35%–7.17% NaCleqv(quartz–scheelite stage), and 0.35%–2.24% NaCleqv(late calcite vein stage). Laser Raman spectroscopic studies on fluid inclusions in the three stages showed H_2O as the main component, with N_2 present in minor amounts. Minor amounts of CH_4 were found in the quartz–scheelite stage. It was observed that the homogenization temperature gradually reduced from the early to the late mineralization stages; moreover, δ^(13)C_(PDB) values for ore-bearing skarn in the mineralization period ranged from -5.7‰ to-6.9‰ and the corresponding δ^(18)O_(SMOW) values ranged from 5.8‰ to 9.1‰, implying that the ore-forming fluid was mainly sourced from magmatic water with a minor amount of meteoric water. Collectively, the evidence indicates that the formation of the Nanyangtian deposit is related to Laojunshan granitic magmatism.
基金financially supported jointly by the National Natural Science Foundation of China (Grant Nos. 41102055and 41102053)the National Basic Research Program of China (Grant No. 2007CB411402)
文摘The Pb-Zn metallogenic district in NW Guizhou Province is an important part of the Yun-nan-Sichuan-Guizhou Pb-Zn metallogenic province, and also is one of the most important Pb-Zn producers in China. The hosting rocks of the Pb-Zn deposits are Devonian to Permian carbonate rocks, and the basement rocks are meta-sedimentary and igneous rocks of the Proterozoic Kunyang and Huili groups. The ore minerals are composed of sphalerite, galena and pyrite, and the gangue minerals are include calcite and dolomite. Geology and C-O isotope of these deposits were studied in this paper. The results show that δ13C and δ18O values of hydrothermal calcite, altered wall rocks-dolostone, sedimentary calcite and hosting carbonate rocks range from -5.3‰ to -0.6 ‰ (mean -3.4‰) and +11.3‰ to +20.9 ‰ (mean +17.2‰), -3.0‰ to +0.9 ‰ (mean -1.3‰) and +17.0‰ to +20.8‰ (mean +19.7‰), +0.6‰ to +2.5 ‰ (mean +1.4‰) and +23.4‰ to +26.5 ‰ (mean +24.6‰), and -1.8‰ to +3.9‰ (mean +0.7‰) and +21.0‰ to +26.8‰ (mean +22.9‰), respectively, implying that CO2 in the ore-forming fluids was mainly a result of dissolution of Devonian and Carboniferous carbonate rocks. However, it is difficult to evaluate the contribution of sediment de-hydroxylation. Based on the integrated analysis of geology, C and O isotopes, it is believed that the ore-forming fluids of these carbonate-hosted Pb-Zn deposits in this area were derived from multiple sources, including hosting carbonate rocks, Devonian to Permian sedimentary rocks and basement rocks (the Kun-yang and Huili groups). Therefore, the fluids mixing is the main precipitation mechanism of the Pb-Zn deposit in this province.