A continuous measurement of number size distributions and chemical composition of aerosol particles was conducted in Beijing in a dust storm event during 21-26 March 2001. The number concentration of coarse particles ...A continuous measurement of number size distributions and chemical composition of aerosol particles was conducted in Beijing in a dust storm event during 21-26 March 2001. The number concentration of coarse particles ( 〉2μm) increased more significantly than fine particles ( 〈2μm) during the dust storm due to dust weather, while the anthropogenic aerosols collected during the non-dust-storm period tended to be associated with fine particles. Elemental compositions were analyzed by using proton-induced X-ray emission (PIXE). The results show that 20 elements in the dust storm were much higher than in the non-dust-storm period. The calculated soil dust concentration during the dust storm was, on average, 251.8μg m^-3, while it was only 52.1μg m^-3 on non-dust-storm days. The enrichment factors for Mg, A1, P, K, Ca, Ti, Mn, Fe, C1, Cu, Pb, and Zn show small variations between the dust storm and the non-dust-storm period, while those for Ca, Ni and Cr in the dust storm were much lower than those in the non-dust-storm period due to significant local emission sources. A high concentration and enrichment factor for S were observed during the dust storm, which implies that the dust particles were contaminated by aerosol particles from anthropogenic emissions during the long-range transport. A statistical analysis shows that the elemental composition of particles collected during the dust storm in Beijing were better correlated with those of desert soil colleted from desert regions in Inner Mongolia. Air mass back-trajectory analysis further confirmed that this dust storm event could be identified as streaks of dust plumes originating from Inner Mongolia.展开更多
The characteristics of daytime and nighttime suburbs PM2.5 in Shanghai were analyzed by synchrotron based X-ray fluorescence during the period of October, 2006 and November, 2007. The mass concentrations of nighttime ...The characteristics of daytime and nighttime suburbs PM2.5 in Shanghai were analyzed by synchrotron based X-ray fluorescence during the period of October, 2006 and November, 2007. The mass concentrations of nighttime PM2.5 was approximately two times that of daytime PM2.5. Some elements, such as Zn, Cu, Mn, Cl were found enriched at night. The local sources might have significant contribution to the nighttime PM2.5 pollutions.展开更多
A spectrum-splitting and beam-concentrating (SSBC) diffractive optical element (DOE) for three-junction pho- tovoltaics (PV) system is designed and fabricated by five-circ/e micro-fabrication. The incident solar...A spectrum-splitting and beam-concentrating (SSBC) diffractive optical element (DOE) for three-junction pho- tovoltaics (PV) system is designed and fabricated by five-circ/e micro-fabrication. The incident solar light is efficiently split into three sub-spectrum ranges and strongly concentrated on the focal plane, which can be di- rectly utilized by suitable spectrum-matching solar cells. The system concentration factor reaches 12x. Moreover, the designed wavelengths (450nm, 550nm and 65Onto) are spatially distributed on the focal plane, in good agree- ment with the theoretical results. The average optical effic/ency of all the cells over the three designed wavelengths is 60.07%. The SSBC DOE with a high concentration factor and a high optical efficiency provides a cost-effective approach to achieve higher PV conversion efficieneies.展开更多
This study focused on the contents of the air particulate matter pollution in two districts of Ulaanbaatar and determined the chemical composition of air borne samples and the source of those particles. Samples of fin...This study focused on the contents of the air particulate matter pollution in two districts of Ulaanbaatar and determined the chemical composition of air borne samples and the source of those particles. Samples of fine and coarse fractions of PM were collected using a “Gent” stacked filter unit in two fractions of 0 - 2.2 μm and 2.2 - 10 μm sizes in two semi-residential areas from September 2012 to August 2013. This paper points out that fine and coarse concentration varied seasonally with meteorological changes. In sampling site 3, Zuun Ail (Figure 1) combustion generators generate the majority of pollution around 50.6% of household waste furnace to create high-temperature combustion of 21.6%. However, this net contributes to soil contamination near the lower value (5%) that arises around the vacuum environment in substantial amounts (14%), where is open around the buildings and residential areas, and the soil is considered to be due to the construction. But the data point to the highway in the distance, where is 9% of contamination of all vehicles’ smoke, and exhaust is similar to the data collected in Ulaanbaatar. According to analysis of samples of Nuclear Research Center (NRC) sampling site 2, it shows burning source of Particulate Matter 2.5 pollution in the air is around 25.5% of household waste furnace to create high-temperature product of combustion. But here the very high net contribution to the pollution of soil, is 31.6%. Today’s emerging dust is around 15.2%, showing that motor vehicle pollution causes 19.7%. Since the analysis was done on a sample-by-sample basis, it is possible to estimate the daily contributions of pollution sources and provide useful information based on a limited number of samples in order to address air quality management issues in Ulaanbaatar.展开更多
The objective of this study was to investigate whether there was distinctive seasonal and zonal variation in the species diversity, biomass, and element accumulation capacities of macroalgae in two major intertidal ma...The objective of this study was to investigate whether there was distinctive seasonal and zonal variation in the species diversity, biomass, and element accumulation capacities of macroalgae in two major intertidal mangrove stand types (Avicennia marina assemblage andSonneratia apetala assemblage) in the Zhanjiang region of southern China. Over a year, 31 species in 15 genera were identified in both mangrove assem-blages, of which the dominant species wereCladophoropsis zollingeriand Enteromorpha clathrat.Macroal-gal species were significantly most abundant in spring (p〈0.05), followed by summer, winter, and autumn. Variation in the zonal distribution of macroalgal species was conspicuous in both intertidal mangrove as-semblages, with the greatest abundance in the middle zone, and the least in the front zone. Patterns in the seasonal and zonal variation in macroalgal biomass in theS. apetalaassemblage were similar to those of macroalgal species diversity in both mangrove assemblages. The seasonal patterns in tissue concentrations of 15 analyzed elements were not uniform among the macroalgaeC. zollingeri,E. clathrata, andGracilaria salicornia in theA. marina assemblage. All three species exhibited variation in their responses to ambient concentrations of different elements, implying their differential ability to absorb and selectively accumulate certain elements.展开更多
The analysis of trace elements in human tooth for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostic and forensic science. This study investiga...The analysis of trace elements in human tooth for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostic and forensic science. This study investigated concentrations of essential and toxic elements (Zn, Cu, Pb, Ni, Co and Cd) using flame atomic absorption spectroscopy (FAAS) and (Na and K) flame atomic emission spectroscopy (FAES) in human tooth obtained from Misan province, Iraq. The influence of smoking habits and born children on the levels of trace elements in additional to dental erosion by some beverages in the tooth samples were investigated. The overall of mean concentrations of (Zn 185.2 ppm, Cu 36.11 ppm, Pb 18.63 ppm, Ni 13.44 ppm, Co 3.45 ppm, and Cd 0.58 ppm, Na 11.683 ppm and K 115.27 ppm), (Zn 178.243 ppm, Cu 35.877 ppm, Pb 15.64 ppm, Ni 12.89 ppm, Co 3.421 ppm, Cd 0.455 ppm, Na 11,558.04 ppm and K 114.04 ppm) in smokers and non-smokers tooth groups respectively, (Zn 81.12 ppm, Cu 24.37 ppm, Pb 11.18 ppm, Ni 13.68 ppm, Co 3.32 ppm, Cd 0.44 ppm, Na 8227 ppm and K 76.42 ppm), (Zn 80.58 ppm, Cu 24.30 ppm, Pb 10.86 ppm, Ni 12.74 ppm, Co 2.71 ppm, Cd 0.23 ppm, Na 8165 ppm and K 72.80 ppm) in mothers and wives tooth groups respectively. However the w/w% loss of tooth immersed in following order of beverages (green tea, black tea, cinnamon, hibiscus, vinegar and citrus aurantifolia (9.09, 9.68, 12.36, 15.01, 16.77 and 17.38), (8.19, 8.25, 9.76, 13.37, 14.02 and 15.33) in smokers and non-smokers groups respectively, (11.25, 11.47, 13.30, 15.75, 19.58, and 20.91), (8.31, 7.96, 11.39, 13.49, 17.40, and 17.67) in mothers and wives groups respectively. However, there is a statistically significant variance found Zn (t<sub>cal</sub> 5.029, t<sub>tab</sub> 2.131), Pb (t<sub>cal</sub> 4.8538, t<sub>tab</sub> 2.131), Ni (t<sub>ca</sub><sub>l</sub> 5.243, t<sub>tab</sub> 2.131), Cd (t<sub>cal</sub> 3.9062, t<sub>tab</sub> 2.131) and Na (t<sub>cal</sub> 3.0832, t<sub>tab</sub> 2.131) between smokers and non-smokers tooth groups. However, the Co (t<sub>cal</sub> 2.7403, t<sub>tab</sub> 2.131) also shows statistically significant variance between mothers and wives groups. There is no statistically significant variance in w/w% loss after immersed the tooth in some beverages but in general it was higher in smokers than non-smokers and in mothers higher than wives.展开更多
The xenoliths in host rocks of hydrothermal gold deposits can generally provide much geochemical information of the deep rocks, which may have an implication for the sources of ore-forming materials. Geochronology and...The xenoliths in host rocks of hydrothermal gold deposits can generally provide much geochemical information of the deep rocks, which may have an implication for the sources of ore-forming materials. Geochronology and geochemical characteristics are reported for a granite xenolith, which is enclosed by the lamprophyre in the Zhenyuan gold deposit(Yunnan Province, SW China). This granite xenolith mainly consists of K-feldspar, quartz, and plagioclase with trace amounts of magnetite, titanite, apatite, zircon, and sulfides. Zircons from the granite xenolith yield a weighted average U-Pb age of 281.1 ± 1.3 Ma(MSWD = 2.1), which could represent the crystallization age of this granite xenolith. The Ti-in-zircon geothermometer and the Mn concentration in apatite calculate that this granite xenolith formed at 685 ± 43℃ with the logf_(O2) values ranging from NNO + 3.7 to NNO + 6.4. The zircons in the granite xenolith have a restricted range of positive ε_(Hf)(t) values ranging from +9.4 to +10.8, and the corresponding Hf TDM2 model ages range from 588 to 678 Ma. The zircon U-Pb age and the Hf isotopic compositions indicate this granite xenolith within the lamprophyre is mainly derived from partial melting of juvenile crustal rocks before the completed closure of the Ailaoshan Ocean. The pyrites in the granite xenolith have higher Bi concentrations, and lower As, Sb, and Tl concentrations than the gold-bearing pyrites of the ores in the Zhenyuan gold deposit. The low Au concentrations of the pyrites together with the ore-forming age of the Zhenyuan gold deposit(Oligocene) indicate the granite xenolith may have limited contribution to the gold mineralization of the Zhenyuan gold deposit.展开更多
In 1999 aerosol samples were collected by cascade at Meteorological Tower in Beijing. The 12 group aerosol samples obtained were analyzed using PIXE method, which resulted in 20 elemental concentrations and size dist...In 1999 aerosol samples were collected by cascade at Meteorological Tower in Beijing. The 12 group aerosol samples obtained were analyzed using PIXE method, which resulted in 20 elemental concentrations and size distribution of elemental concentrations. From the observation, the elemental concentrations, size distribution of elemental concentrations and their variations are analyzed. It shows that concentrations of the most elements in aerosols increase greatly compared with those in the past except that the concentrations of V, K, Sr, and the source of aerosols has changed greatly in the past decade. Fine mode aerosols increase more rapidly in the past decade, which may be due to the contribution of coal combustion and automobile exhaust. Pb content in aerosol is much higher than that at the beginning of 1980s, and has a decreasing trend in recent years because of using non leaded gasoline.展开更多
The late Quaternary shallow-water carbonates have been altered by a variety of diagenetic processes,and further influenced by high-amplitude global and regional sea level changes.This study utilizes a new borehole dri...The late Quaternary shallow-water carbonates have been altered by a variety of diagenetic processes,and further influenced by high-amplitude global and regional sea level changes.This study utilizes a new borehole drilled on the Yongxing Island,Xisha Islands to investigate meteoric diagenetic alteration in the late Quaternary shallowwater carbonates.Petrographic,mineralogical,stable isotopic and elemental data provide new insights into the meteoric diagenetic processes of the reef limestone.The results show the variation in the distribution of aragonite,high-Mg calcite(HMC)and low-Mg calcite(LMC)divides the shallow-water carbonates in Core SSZK1 into three intervals,which are UnitⅠ(31.20-55.92 m,LMC),UnitⅡ(18.39-31.20 m,aragonite and LMC)and UnitⅢ(upper 18.39 m of core,aragonite,LMC and HMC).Various degrees of meteoric diagenesis exist in the identified three units.The lowermost UnitⅠhas suffered almost complete freshwater diagenesis,whereas the overlying UnitsⅡandⅢhave undergone incompletely meteoric diagenesis.The amount of time that limestone has been in the freshwater diagenetic environment has the largest impact on the degree of meteoric diagenesis.Approximately four intact facies/water depth cycles are recognized.The cumulative depletion of elements such as strontium(Sr),sodium(Na)and sulphur(S)caused by duplicated meteoric diagenesis in the older reef sequences are distinguished from the younger reef sequences.This study provides a new record of meteoric diagenesis,which is well reflected by whole-rock mineralogy and geochemistry.展开更多
Sixty water samples (35 groundwater samples, 22 surface water samples and three hot-spring water samples) were collected at 36 points from villages and towns in Lhasa city, Nagchu (Nagqu) prefecture, Ali (Ngari)...Sixty water samples (35 groundwater samples, 22 surface water samples and three hot-spring water samples) were collected at 36 points from villages and towns in Lhasa city, Nagchu (Nagqu) prefecture, Ali (Ngari) prefecture and Shigatse (Xigaze) prefecture (Tibet) in 2013 to study the hydrochemical characteristics and element contents of natural waters. The concentrations of elements were determined in the water samples and compared with the concentrations in water samples from other regions, such as southeast Qinghai, south Xinjiang, east Sichuan and west Tibet. The hydrochemical species in different areas were also studied. Water in most parts of Tibet reaches the requirements of the Chinese national standard and the World Health Organization international standard. The pH values of the water samples ranged from 6.75 to 8.21 and the value for the mean total dissolved solids was 225.54 mg/L. The concentration of arsenic in water from Ali prefecture exceeded the limit of both the Chinese national standard and the international standard and the concentration of fluoride in water from Shuanghu exceeded the limit of both the Chinese national standard and the international standard. The main hydrochemical species in water of Tibet is Ca (HCO3)2. From south to north, the main cation in water changes from Ca^2+ to Na^+, whereas the main anions in water change from HCO3^- to Cl^- and SO4^2-. The chemistry of river water and melt water from ice and snow is dominated by the rocks present at their source, whereas the chemistry of groundwater is affected by many factors. Tectonic divisions determine the con- centrations of the main elements in water and also affect the hydrochemical species present.展开更多
In spite of increasing attention on Chinese aerosol, there has never been a country-wide survey of its general characteristics. This paper presents elemental data for aerosol at 23 sites in and around China, mostly dr...In spite of increasing attention on Chinese aerosol, there has never been a country-wide survey of its general characteristics. This paper presents elemental data for aerosol at 23 sites in and around China, mostly drawn from the literature, and shows some of the large-scale patterns. Al, Na, and Se are used to represent the crustal, marine, and pollution components, respectively. Most of the patterns are aligned in SW-NE. Al and Na are highest to the NW and the SE, respectively, and their ratio changes rapidly near the coast. Se has a broad maximum over Central China, and the Se/Al ratio (an indicator of pollution vs. crustal aerosol) increases progressively from the NW to the SE. A simple index for simulating pollution aerosol, which uses population density, annual precipitation, and mean wind speed, adequately reproduces the large-scale pattern of pollution aerosol and shows how crustal Al in the NW gradually gives way to flyash Al toward the SE.展开更多
文摘A continuous measurement of number size distributions and chemical composition of aerosol particles was conducted in Beijing in a dust storm event during 21-26 March 2001. The number concentration of coarse particles ( 〉2μm) increased more significantly than fine particles ( 〈2μm) during the dust storm due to dust weather, while the anthropogenic aerosols collected during the non-dust-storm period tended to be associated with fine particles. Elemental compositions were analyzed by using proton-induced X-ray emission (PIXE). The results show that 20 elements in the dust storm were much higher than in the non-dust-storm period. The calculated soil dust concentration during the dust storm was, on average, 251.8μg m^-3, while it was only 52.1μg m^-3 on non-dust-storm days. The enrichment factors for Mg, A1, P, K, Ca, Ti, Mn, Fe, C1, Cu, Pb, and Zn show small variations between the dust storm and the non-dust-storm period, while those for Ca, Ni and Cr in the dust storm were much lower than those in the non-dust-storm period due to significant local emission sources. A high concentration and enrichment factor for S were observed during the dust storm, which implies that the dust particles were contaminated by aerosol particles from anthropogenic emissions during the long-range transport. A statistical analysis shows that the elemental composition of particles collected during the dust storm in Beijing were better correlated with those of desert soil colleted from desert regions in Inner Mongolia. Air mass back-trajectory analysis further confirmed that this dust storm event could be identified as streaks of dust plumes originating from Inner Mongolia.
基金Supported by Scientific Research Foundation of Chinese Academy of Sciences (KJCX3-SYW-N3)Scientific Research Foundation of Shanghai Institute of Applied Physics (90070301)National Natural Science Foundation of China (10775174)
文摘The characteristics of daytime and nighttime suburbs PM2.5 in Shanghai were analyzed by synchrotron based X-ray fluorescence during the period of October, 2006 and November, 2007. The mass concentrations of nighttime PM2.5 was approximately two times that of daytime PM2.5. Some elements, such as Zn, Cu, Mn, Cl were found enriched at night. The local sources might have significant contribution to the nighttime PM2.5 pollutions.
基金Supported by the National Natural Science Foundation of China under Grant Nos 91233202,91433205 and 51421002the Chinese Academy of Sciences
文摘A spectrum-splitting and beam-concentrating (SSBC) diffractive optical element (DOE) for three-junction pho- tovoltaics (PV) system is designed and fabricated by five-circ/e micro-fabrication. The incident solar light is efficiently split into three sub-spectrum ranges and strongly concentrated on the focal plane, which can be di- rectly utilized by suitable spectrum-matching solar cells. The system concentration factor reaches 12x. Moreover, the designed wavelengths (450nm, 550nm and 65Onto) are spatially distributed on the focal plane, in good agree- ment with the theoretical results. The average optical effic/ency of all the cells over the three designed wavelengths is 60.07%. The SSBC DOE with a high concentration factor and a high optical efficiency provides a cost-effective approach to achieve higher PV conversion efficieneies.
文摘This study focused on the contents of the air particulate matter pollution in two districts of Ulaanbaatar and determined the chemical composition of air borne samples and the source of those particles. Samples of fine and coarse fractions of PM were collected using a “Gent” stacked filter unit in two fractions of 0 - 2.2 μm and 2.2 - 10 μm sizes in two semi-residential areas from September 2012 to August 2013. This paper points out that fine and coarse concentration varied seasonally with meteorological changes. In sampling site 3, Zuun Ail (Figure 1) combustion generators generate the majority of pollution around 50.6% of household waste furnace to create high-temperature combustion of 21.6%. However, this net contributes to soil contamination near the lower value (5%) that arises around the vacuum environment in substantial amounts (14%), where is open around the buildings and residential areas, and the soil is considered to be due to the construction. But the data point to the highway in the distance, where is 9% of contamination of all vehicles’ smoke, and exhaust is similar to the data collected in Ulaanbaatar. According to analysis of samples of Nuclear Research Center (NRC) sampling site 2, it shows burning source of Particulate Matter 2.5 pollution in the air is around 25.5% of household waste furnace to create high-temperature product of combustion. But here the very high net contribution to the pollution of soil, is 31.6%. Today’s emerging dust is around 15.2%, showing that motor vehicle pollution causes 19.7%. Since the analysis was done on a sample-by-sample basis, it is possible to estimate the daily contributions of pollution sources and provide useful information based on a limited number of samples in order to address air quality management issues in Ulaanbaatar.
基金The Public Science and Technology Research Funds Projects of Ocean in China under contract Nos 201305021 and 201105008-E
文摘The objective of this study was to investigate whether there was distinctive seasonal and zonal variation in the species diversity, biomass, and element accumulation capacities of macroalgae in two major intertidal mangrove stand types (Avicennia marina assemblage andSonneratia apetala assemblage) in the Zhanjiang region of southern China. Over a year, 31 species in 15 genera were identified in both mangrove assem-blages, of which the dominant species wereCladophoropsis zollingeriand Enteromorpha clathrat.Macroal-gal species were significantly most abundant in spring (p〈0.05), followed by summer, winter, and autumn. Variation in the zonal distribution of macroalgal species was conspicuous in both intertidal mangrove as-semblages, with the greatest abundance in the middle zone, and the least in the front zone. Patterns in the seasonal and zonal variation in macroalgal biomass in theS. apetalaassemblage were similar to those of macroalgal species diversity in both mangrove assemblages. The seasonal patterns in tissue concentrations of 15 analyzed elements were not uniform among the macroalgaeC. zollingeri,E. clathrata, andGracilaria salicornia in theA. marina assemblage. All three species exhibited variation in their responses to ambient concentrations of different elements, implying their differential ability to absorb and selectively accumulate certain elements.
文摘The analysis of trace elements in human tooth for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostic and forensic science. This study investigated concentrations of essential and toxic elements (Zn, Cu, Pb, Ni, Co and Cd) using flame atomic absorption spectroscopy (FAAS) and (Na and K) flame atomic emission spectroscopy (FAES) in human tooth obtained from Misan province, Iraq. The influence of smoking habits and born children on the levels of trace elements in additional to dental erosion by some beverages in the tooth samples were investigated. The overall of mean concentrations of (Zn 185.2 ppm, Cu 36.11 ppm, Pb 18.63 ppm, Ni 13.44 ppm, Co 3.45 ppm, and Cd 0.58 ppm, Na 11.683 ppm and K 115.27 ppm), (Zn 178.243 ppm, Cu 35.877 ppm, Pb 15.64 ppm, Ni 12.89 ppm, Co 3.421 ppm, Cd 0.455 ppm, Na 11,558.04 ppm and K 114.04 ppm) in smokers and non-smokers tooth groups respectively, (Zn 81.12 ppm, Cu 24.37 ppm, Pb 11.18 ppm, Ni 13.68 ppm, Co 3.32 ppm, Cd 0.44 ppm, Na 8227 ppm and K 76.42 ppm), (Zn 80.58 ppm, Cu 24.30 ppm, Pb 10.86 ppm, Ni 12.74 ppm, Co 2.71 ppm, Cd 0.23 ppm, Na 8165 ppm and K 72.80 ppm) in mothers and wives tooth groups respectively. However the w/w% loss of tooth immersed in following order of beverages (green tea, black tea, cinnamon, hibiscus, vinegar and citrus aurantifolia (9.09, 9.68, 12.36, 15.01, 16.77 and 17.38), (8.19, 8.25, 9.76, 13.37, 14.02 and 15.33) in smokers and non-smokers groups respectively, (11.25, 11.47, 13.30, 15.75, 19.58, and 20.91), (8.31, 7.96, 11.39, 13.49, 17.40, and 17.67) in mothers and wives groups respectively. However, there is a statistically significant variance found Zn (t<sub>cal</sub> 5.029, t<sub>tab</sub> 2.131), Pb (t<sub>cal</sub> 4.8538, t<sub>tab</sub> 2.131), Ni (t<sub>ca</sub><sub>l</sub> 5.243, t<sub>tab</sub> 2.131), Cd (t<sub>cal</sub> 3.9062, t<sub>tab</sub> 2.131) and Na (t<sub>cal</sub> 3.0832, t<sub>tab</sub> 2.131) between smokers and non-smokers tooth groups. However, the Co (t<sub>cal</sub> 2.7403, t<sub>tab</sub> 2.131) also shows statistically significant variance between mothers and wives groups. There is no statistically significant variance in w/w% loss after immersed the tooth in some beverages but in general it was higher in smokers than non-smokers and in mothers higher than wives.
基金supported by the National Natural Science Foundation of China (Grant Nos. 91962105, 41802113)the Fundamental Research Funds for the Central Universities (Grant No.2019B08214)a grant from Jiangsu Provincial “Double Innovation Doctors” Program (Grant No.(2020) 30462)。
文摘The xenoliths in host rocks of hydrothermal gold deposits can generally provide much geochemical information of the deep rocks, which may have an implication for the sources of ore-forming materials. Geochronology and geochemical characteristics are reported for a granite xenolith, which is enclosed by the lamprophyre in the Zhenyuan gold deposit(Yunnan Province, SW China). This granite xenolith mainly consists of K-feldspar, quartz, and plagioclase with trace amounts of magnetite, titanite, apatite, zircon, and sulfides. Zircons from the granite xenolith yield a weighted average U-Pb age of 281.1 ± 1.3 Ma(MSWD = 2.1), which could represent the crystallization age of this granite xenolith. The Ti-in-zircon geothermometer and the Mn concentration in apatite calculate that this granite xenolith formed at 685 ± 43℃ with the logf_(O2) values ranging from NNO + 3.7 to NNO + 6.4. The zircons in the granite xenolith have a restricted range of positive ε_(Hf)(t) values ranging from +9.4 to +10.8, and the corresponding Hf TDM2 model ages range from 588 to 678 Ma. The zircon U-Pb age and the Hf isotopic compositions indicate this granite xenolith within the lamprophyre is mainly derived from partial melting of juvenile crustal rocks before the completed closure of the Ailaoshan Ocean. The pyrites in the granite xenolith have higher Bi concentrations, and lower As, Sb, and Tl concentrations than the gold-bearing pyrites of the ores in the Zhenyuan gold deposit. The low Au concentrations of the pyrites together with the ore-forming age of the Zhenyuan gold deposit(Oligocene) indicate the granite xenolith may have limited contribution to the gold mineralization of the Zhenyuan gold deposit.
文摘In 1999 aerosol samples were collected by cascade at Meteorological Tower in Beijing. The 12 group aerosol samples obtained were analyzed using PIXE method, which resulted in 20 elemental concentrations and size distribution of elemental concentrations. From the observation, the elemental concentrations, size distribution of elemental concentrations and their variations are analyzed. It shows that concentrations of the most elements in aerosols increase greatly compared with those in the past except that the concentrations of V, K, Sr, and the source of aerosols has changed greatly in the past decade. Fine mode aerosols increase more rapidly in the past decade, which may be due to the contribution of coal combustion and automobile exhaust. Pb content in aerosol is much higher than that at the beginning of 1980s, and has a decreasing trend in recent years because of using non leaded gasoline.
基金The National Natural Science Foundation of China-Guangdong Joint Foundation under contract No.U1701245the Hainan Provincial Natural Science Foundation of China under contract No.418QN306+2 种基金the Land and Georesource Bureau of Hainan Province under contract No.SQ2016KJHZ0027the Pioneer Hundred Talents Program under contract No.Y910091001the Guangzhou Marine Geological Survey Project under contract No.GZH201400210.
文摘The late Quaternary shallow-water carbonates have been altered by a variety of diagenetic processes,and further influenced by high-amplitude global and regional sea level changes.This study utilizes a new borehole drilled on the Yongxing Island,Xisha Islands to investigate meteoric diagenetic alteration in the late Quaternary shallowwater carbonates.Petrographic,mineralogical,stable isotopic and elemental data provide new insights into the meteoric diagenetic processes of the reef limestone.The results show the variation in the distribution of aragonite,high-Mg calcite(HMC)and low-Mg calcite(LMC)divides the shallow-water carbonates in Core SSZK1 into three intervals,which are UnitⅠ(31.20-55.92 m,LMC),UnitⅡ(18.39-31.20 m,aragonite and LMC)and UnitⅢ(upper 18.39 m of core,aragonite,LMC and HMC).Various degrees of meteoric diagenesis exist in the identified three units.The lowermost UnitⅠhas suffered almost complete freshwater diagenesis,whereas the overlying UnitsⅡandⅢhave undergone incompletely meteoric diagenesis.The amount of time that limestone has been in the freshwater diagenetic environment has the largest impact on the degree of meteoric diagenesis.Approximately four intact facies/water depth cycles are recognized.The cumulative depletion of elements such as strontium(Sr),sodium(Na)and sulphur(S)caused by duplicated meteoric diagenesis in the older reef sequences are distinguished from the younger reef sequences.This study provides a new record of meteoric diagenesis,which is well reflected by whole-rock mineralogy and geochemistry.
基金National Key Technologies R&D Program in the 12th Five-Year Plan of China, No.2011 BAD 17B05-4, No.2011BAC09B03 National Key Basic Research Program of China (973 Program), No.2014CB238906 National Natural Science Foundation of China, No.40872210, No.41172310, No.40171006
文摘Sixty water samples (35 groundwater samples, 22 surface water samples and three hot-spring water samples) were collected at 36 points from villages and towns in Lhasa city, Nagchu (Nagqu) prefecture, Ali (Ngari) prefecture and Shigatse (Xigaze) prefecture (Tibet) in 2013 to study the hydrochemical characteristics and element contents of natural waters. The concentrations of elements were determined in the water samples and compared with the concentrations in water samples from other regions, such as southeast Qinghai, south Xinjiang, east Sichuan and west Tibet. The hydrochemical species in different areas were also studied. Water in most parts of Tibet reaches the requirements of the Chinese national standard and the World Health Organization international standard. The pH values of the water samples ranged from 6.75 to 8.21 and the value for the mean total dissolved solids was 225.54 mg/L. The concentration of arsenic in water from Ali prefecture exceeded the limit of both the Chinese national standard and the international standard and the concentration of fluoride in water from Shuanghu exceeded the limit of both the Chinese national standard and the international standard. The main hydrochemical species in water of Tibet is Ca (HCO3)2. From south to north, the main cation in water changes from Ca^2+ to Na^+, whereas the main anions in water change from HCO3^- to Cl^- and SO4^2-. The chemistry of river water and melt water from ice and snow is dominated by the rocks present at their source, whereas the chemistry of groundwater is affected by many factors. Tectonic divisions determine the con- centrations of the main elements in water and also affect the hydrochemical species present.
基金the National Natural Science Foundation of China (Grant Nos. 29837190, 20077004, and 30230310).
文摘In spite of increasing attention on Chinese aerosol, there has never been a country-wide survey of its general characteristics. This paper presents elemental data for aerosol at 23 sites in and around China, mostly drawn from the literature, and shows some of the large-scale patterns. Al, Na, and Se are used to represent the crustal, marine, and pollution components, respectively. Most of the patterns are aligned in SW-NE. Al and Na are highest to the NW and the SE, respectively, and their ratio changes rapidly near the coast. Se has a broad maximum over Central China, and the Se/Al ratio (an indicator of pollution vs. crustal aerosol) increases progressively from the NW to the SE. A simple index for simulating pollution aerosol, which uses population density, annual precipitation, and mean wind speed, adequately reproduces the large-scale pattern of pollution aerosol and shows how crustal Al in the NW gradually gives way to flyash Al toward the SE.