Sediment core samples collected from Lake Chaohu were analyzed for 15 priority polycyclic aromatic hydrocarbons（PAHs）to assess the spatial and temporal distributions of the PAHs during lacustrine sedimentary process...Sediment core samples collected from Lake Chaohu were analyzed for 15 priority polycyclic aromatic hydrocarbons（PAHs）to assess the spatial and temporal distributions of the PAHs during lacustrine sedimentary processes and regional economic development.Assessing the PAH sedimentary records over an approximately 100-year time span,we identified two stages in the PAH inputs and sources（before the 1970 s and after the 1970s）in the eastern lake region near a village,whereas three stages（before the 1950 s,1950s–1990s and after the1990s）were identified in the western lake region near urban and industrial areas.Rapid increases in the PAH depositional fluxes occurred during the second stage due to increased human activities in the Lake Chaohu basin.The composition and isomeric ratios of the PAHs revealed that pyrolysis is the main source of PAHs in this lake.Strong positive relationships between PAH concentration and the total organic carbon concentration,sediment grain size（〈 4 μm）,as well as the local population and Gross Domestic Product indicated that the sedimentary conditions impact the depositional characteristics of the PAHs;simultaneously,socioeconomic activities,such as energy consumption and the levels of urban industrialization and civilization,affect both the composition and abundance of the PAHs.展开更多
Sedimentological and chemostratigraphical studies using accessory elements on 322 samples of cuttings from oil wells located in the submerged sedimentary basin (offshore) of Côte d’Ivoire. This basin covered the...Sedimentological and chemostratigraphical studies using accessory elements on 322 samples of cuttings from oil wells located in the submerged sedimentary basin (offshore) of Côte d’Ivoire. This basin covered the chronostratigraphic interval from the Upper Albian to the top of the Maastrichtian. The aim of this study was to determine the major accident, the Albo-Cenomanian unconformity, using chemical elements. To achieve this goal, we had to count the accessory elements glauconite, pyrite and carbonaceous debris, and identify all the chemical elements present in each cuttings sample. The results clearly indicate that: the sediments are essentially composed of carbonaceous debris and pyrite, with a high potassium content for sediments dating from the Abian period;and glauconite, carbonaceous debris, pyrite, and a sharp decrease in potassium content for sediments dating from the Cenomanian to the Maastrichtian period. Threshold values for ratios of source-indicating chemical elements (Zr, Ti, Y, Th) and paleoenvironmental elements (K, Rb, Mg, Al,) highlighted the MS1 and MS2 mega-sequences in the study area. The difference observed in the threshold values of these ratios can be explained by changes in sedimentary dynamics. The depositional environment varies from an inner continental shelf with strong littoral influence (Upper Albian) to an increasing subsidence outer continental shelf (Cenomanian-K/Pg boundary).展开更多
Surface sediments were collected from Lake Manzala, the Mediterranean coastal wetland located to the east of the Nile Delta, Egypt, to assess the effect of drain effluent on the spatial variations of sedimentary chara...Surface sediments were collected from Lake Manzala, the Mediterranean coastal wetland located to the east of the Nile Delta, Egypt, to assess the effect of drain effluent on the spatial variations of sedimentary characteristics and heavy metal pollution. Grain-size compositions, textures, and heavy metal distribution patterns in sediments are presented using GIS technique. Results of the analysis of the sediment showed a clear effect of drain effluent, with an increase in fine fractions and homogeneous suspensions in transportation mode. Lake sediments were dominated by sandy mud textures, and mode of transportation was homogeneous sus- pension and rolling. Spatial distribution of heavy metals (Fe, Mn, Zn, Cu, Ni, Cr, and Pb) was studied in the lake’s surficial sediments, along with their relationship to drain effluent and their contamination status in the ecological system. Heavy metal pollution status was assessed by means of accepted sediment quality guidelines and contamination assessment methods (contamination factor, con- tamination degree, modified contamination degree, geo-accumulation, and enrichment factor). Among the determined heavy metals, Pb had the most ecological risk. Generally, the heavy metals in the surface sediments indicated pollution risk ranging from moderate to considerable, particularly, in those sites facing drains and inlets that had the highest toxic effluent. The results were interpreted by statistical means. A cluster analysis defined areas facing drain discharge and inlets as separated groups. ANOVA indicated that most of the sedimentation and studied metals directed this clustering.展开更多
During August 18-22, 2014, the 19^th International Sedimentological Congress was successfully held by the International Association of Sedimentology in Geneva, Switzerland.
Surface sediment samples were collected from 35 locations in Sulaibikhat Bay, Kuwait. Co, Cr, Cu, Ni, Pb and Zn concentrations were determined. Grain sizes, TOC （total organic carbon）, carbonate, mineralogical and e...Surface sediment samples were collected from 35 locations in Sulaibikhat Bay, Kuwait. Co, Cr, Cu, Ni, Pb and Zn concentrations were determined. Grain sizes, TOC （total organic carbon）, carbonate, mineralogical and environmental data were also determined. Multiple linear regression is applied to the data from the sediment sequential extractions to assess the relative importance of mineralogical and sedimentological factors in controlling heavy metal concentrations in individual chemical fractions （exchangeable, reducible, oxidizable, residual） under different environmental conditions. The analysis shows that grain size, TOC, calcium carbonate and minerals clearly influence heavy metal concentrations. For the exchangeable fraction, clay, grain size and the mineral pyrite are the main factors, whereas for the reducible fraction, TOC is the main factor influencing concentrations ofZn, Pb, Ni, Cu and Cr. For the oxidizable fraction, modelling shows that TOC is the main factor influencing Zn, Ni, Cu, Cr and Co concentrations. The residual fraction concentrations of Zn, Ni, Cr and Co were best predicted by the abundance of sand, with sand content having a negative effect on heavy metal concentrations in this fraction. The statistical techniques in environmental data interpretation are quite useful in cutting down the volume of the data and identifying identical classes which are statistically distinct.展开更多
The Major Research Program "Deep Sea Processes and Evolution of the South China Sea", or "The South China Sea Deep", launched in January 2011 by the National Natural Science Foundation of China, is...The Major Research Program "Deep Sea Processes and Evolution of the South China Sea", or "The South China Sea Deep", launched in January 2011 by the National Natural Science Foundation of China, is the first large-scale basic-research program in ocean science in the country aiming to reconstruct the life history of a marginal sea. The overall scientific objective of the program is to dissect this typical marginal sea by studying its history of evolution and its modern processes, including the following three major components:(1) Development of the deep basin:utilizing new techniques to re-measure magnetic anomaly lineations, to explore the deep tectonic features, to drill the oceanic crust, and to study volcanic seamount chains; (2) deep-water sediments: observing the modern processes to reveal the patterns of deep-water circulations and sedimentation, analyzing deep-sea sediments to recognize paleoceanographic response to basin evolution, and subsequently to bridge the modern and paleo-studies of the deep-sea processes; and (3) biogeochemical processes:using a variety of techniques including deploying submarine observation and deep-water diving device to investigate the distribution patterns and environmental impacts of deepwater seepages and sub-bottom circulation, and to reveal the role of microbes in deep-sea carbon cycling. As compared with the open ocean and other marginal seas, the South China Sea enjoys many more advantages as a marine basin for reconstructing the life history. Meanwhile, the South China Sea Deep Program provides unique opportunities in studying the evolution and variations of the sea-land interactions between the Pacific and Asia.展开更多
基金supported by the Mega-projects of Science Research for Water Environment Improvement(No.2012ZX07101-002)the National Natural Science Foundation of China(No.41303085)
文摘Sediment core samples collected from Lake Chaohu were analyzed for 15 priority polycyclic aromatic hydrocarbons（PAHs）to assess the spatial and temporal distributions of the PAHs during lacustrine sedimentary processes and regional economic development.Assessing the PAH sedimentary records over an approximately 100-year time span,we identified two stages in the PAH inputs and sources（before the 1970 s and after the 1970s）in the eastern lake region near a village,whereas three stages（before the 1950 s,1950s–1990s and after the1990s）were identified in the western lake region near urban and industrial areas.Rapid increases in the PAH depositional fluxes occurred during the second stage due to increased human activities in the Lake Chaohu basin.The composition and isomeric ratios of the PAHs revealed that pyrolysis is the main source of PAHs in this lake.Strong positive relationships between PAH concentration and the total organic carbon concentration,sediment grain size（〈 4 μm）,as well as the local population and Gross Domestic Product indicated that the sedimentary conditions impact the depositional characteristics of the PAHs;simultaneously,socioeconomic activities,such as energy consumption and the levels of urban industrialization and civilization,affect both the composition and abundance of the PAHs.
文摘Sedimentological and chemostratigraphical studies using accessory elements on 322 samples of cuttings from oil wells located in the submerged sedimentary basin (offshore) of Côte d’Ivoire. This basin covered the chronostratigraphic interval from the Upper Albian to the top of the Maastrichtian. The aim of this study was to determine the major accident, the Albo-Cenomanian unconformity, using chemical elements. To achieve this goal, we had to count the accessory elements glauconite, pyrite and carbonaceous debris, and identify all the chemical elements present in each cuttings sample. The results clearly indicate that: the sediments are essentially composed of carbonaceous debris and pyrite, with a high potassium content for sediments dating from the Abian period;and glauconite, carbonaceous debris, pyrite, and a sharp decrease in potassium content for sediments dating from the Cenomanian to the Maastrichtian period. Threshold values for ratios of source-indicating chemical elements (Zr, Ti, Y, Th) and paleoenvironmental elements (K, Rb, Mg, Al,) highlighted the MS1 and MS2 mega-sequences in the study area. The difference observed in the threshold values of these ratios can be explained by changes in sedimentary dynamics. The depositional environment varies from an inner continental shelf with strong littoral influence (Upper Albian) to an increasing subsidence outer continental shelf (Cenomanian-K/Pg boundary).
文摘Surface sediments were collected from Lake Manzala, the Mediterranean coastal wetland located to the east of the Nile Delta, Egypt, to assess the effect of drain effluent on the spatial variations of sedimentary characteristics and heavy metal pollution. Grain-size compositions, textures, and heavy metal distribution patterns in sediments are presented using GIS technique. Results of the analysis of the sediment showed a clear effect of drain effluent, with an increase in fine fractions and homogeneous suspensions in transportation mode. Lake sediments were dominated by sandy mud textures, and mode of transportation was homogeneous sus- pension and rolling. Spatial distribution of heavy metals (Fe, Mn, Zn, Cu, Ni, Cr, and Pb) was studied in the lake’s surficial sediments, along with their relationship to drain effluent and their contamination status in the ecological system. Heavy metal pollution status was assessed by means of accepted sediment quality guidelines and contamination assessment methods (contamination factor, con- tamination degree, modified contamination degree, geo-accumulation, and enrichment factor). Among the determined heavy metals, Pb had the most ecological risk. Generally, the heavy metals in the surface sediments indicated pollution risk ranging from moderate to considerable, particularly, in those sites facing drains and inlets that had the highest toxic effluent. The results were interpreted by statistical means. A cluster analysis defined areas facing drain discharge and inlets as separated groups. ANOVA indicated that most of the sedimentation and studied metals directed this clustering.
文摘During August 18-22, 2014, the 19^th International Sedimentological Congress was successfully held by the International Association of Sedimentology in Geneva, Switzerland.
文摘Surface sediment samples were collected from 35 locations in Sulaibikhat Bay, Kuwait. Co, Cr, Cu, Ni, Pb and Zn concentrations were determined. Grain sizes, TOC （total organic carbon）, carbonate, mineralogical and environmental data were also determined. Multiple linear regression is applied to the data from the sediment sequential extractions to assess the relative importance of mineralogical and sedimentological factors in controlling heavy metal concentrations in individual chemical fractions （exchangeable, reducible, oxidizable, residual） under different environmental conditions. The analysis shows that grain size, TOC, calcium carbonate and minerals clearly influence heavy metal concentrations. For the exchangeable fraction, clay, grain size and the mineral pyrite are the main factors, whereas for the reducible fraction, TOC is the main factor influencing concentrations ofZn, Pb, Ni, Cu and Cr. For the oxidizable fraction, modelling shows that TOC is the main factor influencing Zn, Ni, Cu, Cr and Co concentrations. The residual fraction concentrations of Zn, Ni, Cr and Co were best predicted by the abundance of sand, with sand content having a negative effect on heavy metal concentrations in this fraction. The statistical techniques in environmental data interpretation are quite useful in cutting down the volume of the data and identifying identical classes which are statistically distinct.
基金supported by the National Natural Science Foundation of China (91128000)the National Basic Research Program of China (2007CB815902)
文摘The Major Research Program "Deep Sea Processes and Evolution of the South China Sea", or "The South China Sea Deep", launched in January 2011 by the National Natural Science Foundation of China, is the first large-scale basic-research program in ocean science in the country aiming to reconstruct the life history of a marginal sea. The overall scientific objective of the program is to dissect this typical marginal sea by studying its history of evolution and its modern processes, including the following three major components:(1) Development of the deep basin:utilizing new techniques to re-measure magnetic anomaly lineations, to explore the deep tectonic features, to drill the oceanic crust, and to study volcanic seamount chains; (2) deep-water sediments: observing the modern processes to reveal the patterns of deep-water circulations and sedimentation, analyzing deep-sea sediments to recognize paleoceanographic response to basin evolution, and subsequently to bridge the modern and paleo-studies of the deep-sea processes; and (3) biogeochemical processes:using a variety of techniques including deploying submarine observation and deep-water diving device to investigate the distribution patterns and environmental impacts of deepwater seepages and sub-bottom circulation, and to reveal the role of microbes in deep-sea carbon cycling. As compared with the open ocean and other marginal seas, the South China Sea enjoys many more advantages as a marine basin for reconstructing the life history. Meanwhile, the South China Sea Deep Program provides unique opportunities in studying the evolution and variations of the sea-land interactions between the Pacific and Asia.
