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; mu...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% to 16.34% 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 H2O as the main component, with N2 present in minor amounts. Minor amounts of CH4 were found in the quartz-scheelite stage. It was observed that the homogenization temperature gradu- ally reduced from the early to the late mineralization stages; moreover, δ^13CI, DB values for ore-bearing skarn in the mineralization period ranged from - 5.7%0 to - 6.9‰ and the corresponding δ^18OsMow values ranged from 5.8%0 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 thatthe formation of the Nanyangtian deposit is related to Laojunshan granitic magmatism.展开更多
Arctic clouds strongly influence the regional radiation balance, temperature, melting of sea ice, and freezing of sea water. Despite their importance, there is a lack of systematic and reliabie observations of Arctic ...Arctic clouds strongly influence the regional radiation balance, temperature, melting of sea ice, and freezing of sea water. Despite their importance, there is a lack of systematic and reliabie observations of Arctic clouds. The CloudSat satellite launched in 2006 with a 94GHz Cloud Profiling Radar （CPR） may contribute to close this gap. Here we compare one of the key parameters, the cloud liquid water path （LWP） retrieved from CloudSat observations and from microwave radiometer （MWR） data taken during the ASCOS （Arctic Summer Cloud Ocean Study） cruise of the research vessel Oden from August to September 2008. Over the 45 days of the ASCOS cruise, collocations closer than 3 h and 100 km were found in only 9 d, and collocations closer than 1 h and 30 km in only 2 d. The poor correlations in the scatter plots of the two LWP retrievals can be explained by the patchiness of the cloud cover in these two days （August 5th and September 7th）, as confirmed by coincident MODIS （Moderate-resolution Imaging Spectroradiome- ter） images. The averages of Oden-observed LWP values are systematically higher （40-70 g m-2） than the corresponding CloudSat observations （0-50 g m2）. These are cases of generally low LWP with presumably small droplets, and may be explained by the little sensitivity of the CPR to small droplets or by the surface clutter.展开更多
The adsorption of dedecyltrimethylammoium chloride(DTAC) and hexadecyltrimethylammoium chloride(CTAC) on muscovite mica substrates was examined using atomic force microscopy(AFM). Adsorption morphology images and inte...The adsorption of dedecyltrimethylammoium chloride(DTAC) and hexadecyltrimethylammoium chloride(CTAC) on muscovite mica substrates was examined using atomic force microscopy(AFM). Adsorption morphology images and interaction forces of cationic surfactants at solid-solution interfaces were measured in tapping mode and Pico Force mode, respectively. The images demonstrated that the adsorbed structure was varied by a variety of surfactant concentrations. The adsorbed layer on mica was monolayer at first, and then became bilayer. A striped adsorbed structure was observed in a higher concentration of CTAC,which could not be found in any other concentrations of DTAC. For force measurements, the repulsive force was exponentially decreasing with the concentration increasing till a net attractive force appeared. A largest attractive force could be observed at a certain concentration, which was close to the point of charge neutralization. The results also showed a significant impact of hydrocarbon chain length on adsorption. An adsorption simulation was established to give a clear understanding of the interaction between cationic surfactants and mica.展开更多
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% to 16.34% 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 H2O as the main component, with N2 present in minor amounts. Minor amounts of CH4 were found in the quartz-scheelite stage. It was observed that the homogenization temperature gradu- ally reduced from the early to the late mineralization stages; moreover, δ^13CI, DB values for ore-bearing skarn in the mineralization period ranged from - 5.7%0 to - 6.9‰ and the corresponding δ^18OsMow values ranged from 5.8%0 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 thatthe formation of the Nanyangtian deposit is related to Laojunshan granitic magmatism.
基金ASCOS was made possible by grants from DAMOCLES and the Knut and Alice Wallenberg Foundation,and was organized by the Swedish Polar Research Secretariat
文摘Arctic clouds strongly influence the regional radiation balance, temperature, melting of sea ice, and freezing of sea water. Despite their importance, there is a lack of systematic and reliabie observations of Arctic clouds. The CloudSat satellite launched in 2006 with a 94GHz Cloud Profiling Radar （CPR） may contribute to close this gap. Here we compare one of the key parameters, the cloud liquid water path （LWP） retrieved from CloudSat observations and from microwave radiometer （MWR） data taken during the ASCOS （Arctic Summer Cloud Ocean Study） cruise of the research vessel Oden from August to September 2008. Over the 45 days of the ASCOS cruise, collocations closer than 3 h and 100 km were found in only 9 d, and collocations closer than 1 h and 30 km in only 2 d. The poor correlations in the scatter plots of the two LWP retrievals can be explained by the patchiness of the cloud cover in these two days （August 5th and September 7th）, as confirmed by coincident MODIS （Moderate-resolution Imaging Spectroradiome- ter） images. The averages of Oden-observed LWP values are systematically higher （40-70 g m-2） than the corresponding CloudSat observations （0-50 g m2）. These are cases of generally low LWP with presumably small droplets, and may be explained by the little sensitivity of the CPR to small droplets or by the surface clutter.
基金Project(50974134)supported by the National Natural Science Foundation of China
文摘The adsorption of dedecyltrimethylammoium chloride(DTAC) and hexadecyltrimethylammoium chloride(CTAC) on muscovite mica substrates was examined using atomic force microscopy(AFM). Adsorption morphology images and interaction forces of cationic surfactants at solid-solution interfaces were measured in tapping mode and Pico Force mode, respectively. The images demonstrated that the adsorbed structure was varied by a variety of surfactant concentrations. The adsorbed layer on mica was monolayer at first, and then became bilayer. A striped adsorbed structure was observed in a higher concentration of CTAC,which could not be found in any other concentrations of DTAC. For force measurements, the repulsive force was exponentially decreasing with the concentration increasing till a net attractive force appeared. A largest attractive force could be observed at a certain concentration, which was close to the point of charge neutralization. The results also showed a significant impact of hydrocarbon chain length on adsorption. An adsorption simulation was established to give a clear understanding of the interaction between cationic surfactants and mica.
