The δ18O values of vein quartz of different stages from the Yinshan ore deposit are constant around 16‰ and the calculated δ18OH2O values attain 8‰± ; the δDH2O values of fluid inclu-sions in vein quartz are...The δ18O values of vein quartz of different stages from the Yinshan ore deposit are constant around 16‰ and the calculated δ18OH2O values attain 8‰± ; the δDH2O values of fluid inclu-sions in vein quartz are constant at about-60‰. From the surface down to 1200 m below the δ18O values of altered rocks gradually decrease from 15‰± to 11‰± . Various water-rock inversion calculations indicate that the ore fluids were formed by the interaction between meteoric water and phyllite at 350℃ and the effective W/ R value of around 0.1. When the water-rock exchange in the upper mineralization system took place, the effective W / R value increased to 5.0 or more. As a result, an evolution and mineralization model of a buffered open system with two-stage water-rock interactions is proposed in this study.展开更多
The Jinman deposit is a Ag-bearing copper vein deposit located at the north marginof the Lanping-Simao back-arc basin in West Yunnan. Systematic studies of fluid inclusions andstable isotopes are presented in this pap...The Jinman deposit is a Ag-bearing copper vein deposit located at the north marginof the Lanping-Simao back-arc basin in West Yunnan. Systematic studies of fluid inclusions andstable isotopes are presented in this paper. The filling-replacement stage and the boiling-exhala-tive precipitation stage of mineralization took place at T1 = 140 - 280℃ and T2 = 94 - 204℃under pressure of (600 - 1200) ×105 Pa. The salinity of ore-forming solutions ranges from 5 wt%-20. 8 wt% (NaCl). Sulphide δ34S(CDT) values are in the rang of - 9.6‰ - + 11.03% witha range of 22. 66‰ showing an apparent "pagoda"-shaped distribution in histogram. Mean-while, the δ34S values of the various sulphides are consistent with the characters of isotope equi-librium fractionation, i. e., δ34SPy>δ34 SCp> δ34SBn. The TS/TOC ratios of the ores are widelyvariable between 0.16 and 5. 54 with no correlation of any kind can be established. Accirding to themodel of Ohmoto, the oxidation-reduction ratios of sulfur species in ore-forming solutions at the twomineralization stages were calculated to be R’1 = 2. 16×10(-17) and R’2 = 1. 55×104. δ13CCO2 (PDB)values obtained from fluid inclusions in calcite and quartz are between - 8.12‰ - - 3. 18‰, av-eraging - 5. 26‰, which are comparable with the isotopic composition of mantle-derived CO2.Inclusions in quartz yield δ13CCH4(PDB) between - 32. 11‰ and - 22. 04‰ (averaging- 26. 69‰),similar to that of methane in modern geothermal gases. For the ore-forming soutions, δ18OH2O(SMOW) values are between - 10. 57‰ and + 9. 77‰ and δDH2O(SMOW) are between - 51‰and - 135‰. Considering the effect of isotope exchange during waterrock reactions, most ofthe data are plotted along or close to the line defined by the reaction of meteoric water withclastic rocks, while a small part of the points fall near the reaction line of magmatic water withclastic rocks. In δ13C vs. δ18O diagram, the ore-forming soutions are plotted for the most partinto the mixing area between the meteoric fluid and the deep-seated fluid and partially on themixing line of P = 1.展开更多
The aim of study was to detect H5N1 virus in wild geese in Qinghai Province in 2012. The work was provided according to WHO and OIE guidelines. In 2012, we collected 532 samples from wild geese of two species: Bar-hea...The aim of study was to detect H5N1 virus in wild geese in Qinghai Province in 2012. The work was provided according to WHO and OIE guidelines. In 2012, we collected 532 samples from wild geese of two species: Bar-headed Goose (Anser indicus) and Graylag Goose (Anser anser). We analyzed samples by chicken embryo inoculation and PCR. No avian influenza viruses were isolated. History of HPAI H5N1 shows obvious importance of Central Asian region in its spreading. The outbreaks of the H5N1 Highly Pathogenic Avian Influenza (HPAI H5N1) were reported in wild birds at the Qinghai Lake since 2005. This area seems to be key point for H5N1 avian influenza surveillance in wild birds. We did not find viruses although H5N1 cases in poultry were reported from 5 provinces of China in 2012. Annual surveillance is required for early AIV detection in this region.展开更多
The thermodynamic calculation of dehydration reacton suggests very low activity of H\-2O during metamorphic peak of the Archaean granulite complex in the region studied.The a\-\{H\-2O\} values for Al\|rich gneiss and ...The thermodynamic calculation of dehydration reacton suggests very low activity of H\-2O during metamorphic peak of the Archaean granulite complex in the region studied.The a\-\{H\-2O\} values for Al\|rich gneiss and hypersthene biotite gneiss\|granulite in the Taipingzhai region are usually between 0.10 and \{0.20\},and those in the Louzishan region are \{0.15\}-\{0.25\}. The fugacity of O\-2 in terms of lgf\-\{O\-2\} in the whole region ranges from -8 to -14. The average coefficients of (μ\-\{H\-2O\}/X\+\{Bt\}\-\{Mg\}) and (μ\-\{O\-2\}/X\+\{Bt\}\-\{Mg\}) in the Taipingzhai region are \{-0.293\} and \{-1.60\} respectively,and those in the Louzishan region are \{-0.364\} and \{-1.420\}. The activity of H\-2O is very low in the whole region, but its values and other data mentioned above are considerably constant from place to place within a given region, even in rocks of different lithological characters. However, they show a certain gradient between different regions. Such characteristics are compatible with the genetic mechanism known as \!carbonic metamorphism" put forward by Newton et al.,i.e., the a\-\{H\-2O\} during the peak stage is controlled by permeation of pervasive CO\-2 influx of the mantle source,and shows features of external buffering.展开更多
基金This research was supported by the National Natural Science Foundation of China (Grant No. 49473176)the Chinese Foundation for the Development of Geological Science and Technology(Grant No. 89042)
文摘The δ18O values of vein quartz of different stages from the Yinshan ore deposit are constant around 16‰ and the calculated δ18OH2O values attain 8‰± ; the δDH2O values of fluid inclu-sions in vein quartz are constant at about-60‰. From the surface down to 1200 m below the δ18O values of altered rocks gradually decrease from 15‰± to 11‰± . Various water-rock inversion calculations indicate that the ore fluids were formed by the interaction between meteoric water and phyllite at 350℃ and the effective W/ R value of around 0.1. When the water-rock exchange in the upper mineralization system took place, the effective W / R value increased to 5.0 or more. As a result, an evolution and mineralization model of a buffered open system with two-stage water-rock interactions is proposed in this study.
文摘The Jinman deposit is a Ag-bearing copper vein deposit located at the north marginof the Lanping-Simao back-arc basin in West Yunnan. Systematic studies of fluid inclusions andstable isotopes are presented in this paper. The filling-replacement stage and the boiling-exhala-tive precipitation stage of mineralization took place at T1 = 140 - 280℃ and T2 = 94 - 204℃under pressure of (600 - 1200) ×105 Pa. The salinity of ore-forming solutions ranges from 5 wt%-20. 8 wt% (NaCl). Sulphide δ34S(CDT) values are in the rang of - 9.6‰ - + 11.03% witha range of 22. 66‰ showing an apparent "pagoda"-shaped distribution in histogram. Mean-while, the δ34S values of the various sulphides are consistent with the characters of isotope equi-librium fractionation, i. e., δ34SPy>δ34 SCp> δ34SBn. The TS/TOC ratios of the ores are widelyvariable between 0.16 and 5. 54 with no correlation of any kind can be established. Accirding to themodel of Ohmoto, the oxidation-reduction ratios of sulfur species in ore-forming solutions at the twomineralization stages were calculated to be R’1 = 2. 16×10(-17) and R’2 = 1. 55×104. δ13CCO2 (PDB)values obtained from fluid inclusions in calcite and quartz are between - 8.12‰ - - 3. 18‰, av-eraging - 5. 26‰, which are comparable with the isotopic composition of mantle-derived CO2.Inclusions in quartz yield δ13CCH4(PDB) between - 32. 11‰ and - 22. 04‰ (averaging- 26. 69‰),similar to that of methane in modern geothermal gases. For the ore-forming soutions, δ18OH2O(SMOW) values are between - 10. 57‰ and + 9. 77‰ and δDH2O(SMOW) are between - 51‰and - 135‰. Considering the effect of isotope exchange during waterrock reactions, most ofthe data are plotted along or close to the line defined by the reaction of meteoric water withclastic rocks, while a small part of the points fall near the reaction line of magmatic water withclastic rocks. In δ13C vs. δ18O diagram, the ore-forming soutions are plotted for the most partinto the mixing area between the meteoric fluid and the deep-seated fluid and partially on themixing line of P = 1.
文摘The aim of study was to detect H5N1 virus in wild geese in Qinghai Province in 2012. The work was provided according to WHO and OIE guidelines. In 2012, we collected 532 samples from wild geese of two species: Bar-headed Goose (Anser indicus) and Graylag Goose (Anser anser). We analyzed samples by chicken embryo inoculation and PCR. No avian influenza viruses were isolated. History of HPAI H5N1 shows obvious importance of Central Asian region in its spreading. The outbreaks of the H5N1 Highly Pathogenic Avian Influenza (HPAI H5N1) were reported in wild birds at the Qinghai Lake since 2005. This area seems to be key point for H5N1 avian influenza surveillance in wild birds. We did not find viruses although H5N1 cases in poultry were reported from 5 provinces of China in 2012. Annual surveillance is required for early AIV detection in this region.
文摘The thermodynamic calculation of dehydration reacton suggests very low activity of H\-2O during metamorphic peak of the Archaean granulite complex in the region studied.The a\-\{H\-2O\} values for Al\|rich gneiss and hypersthene biotite gneiss\|granulite in the Taipingzhai region are usually between 0.10 and \{0.20\},and those in the Louzishan region are \{0.15\}-\{0.25\}. The fugacity of O\-2 in terms of lgf\-\{O\-2\} in the whole region ranges from -8 to -14. The average coefficients of (μ\-\{H\-2O\}/X\+\{Bt\}\-\{Mg\}) and (μ\-\{O\-2\}/X\+\{Bt\}\-\{Mg\}) in the Taipingzhai region are \{-0.293\} and \{-1.60\} respectively,and those in the Louzishan region are \{-0.364\} and \{-1.420\}. The activity of H\-2O is very low in the whole region, but its values and other data mentioned above are considerably constant from place to place within a given region, even in rocks of different lithological characters. However, they show a certain gradient between different regions. Such characteristics are compatible with the genetic mechanism known as \!carbonic metamorphism" put forward by Newton et al.,i.e., the a\-\{H\-2O\} during the peak stage is controlled by permeation of pervasive CO\-2 influx of the mantle source,and shows features of external buffering.
