This study was conducted to reveal the vertical distribution and concentration variation of heavy metals（Cr, Co, Ni, Cu, Zn, As, Cd and Pb） in the mangrove sediments of Dongzhai Harbor, Hainan by using inductively-c...This study was conducted to reveal the vertical distribution and concentration variation of heavy metals（Cr, Co, Ni, Cu, Zn, As, Cd and Pb） in the mangrove sediments of Dongzhai Harbor, Hainan by using inductively-coupled plasma mass spectrometry（ICP-MS）. The surface sediment samples were collected from 15 sites, and a geoaccumulation index（Igeo） was estimated to quantify the pollution status of the mangrove sediments. The results showed that the concentrations of heavy metals in sediments followed the order of Cr〉 Zn〉 Ni〉 Cu 〉Pb 〉Co〉 Cd. A common pattern was found in some heavy metals（Cu, Zn, As and Pb） as their concentrations were significantly and negatively correlated with depth. Cr concentration in upper layer was slightly lower than that in middle and lower layers,while the concentrations of Ni and Cd in middle layer were slightly higher than in upper and lower layers. The geoaccumulation index indicated that the surface sediments at sites QT-1-01, QT-1-02, QT-2, GN-1, GN-2 and GN-3 were strongly polluted by Cd, and unpolluted to moderately polluted or moderately polluted by As.展开更多
The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57′–104°57′E, 37°48′–39°17′N) in northwestern China, which has a 10 000-year-long paleo-climatic prox...The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57′–104°57′E, 37°48′–39°17′N) in northwestern China, which has a 10 000-year-long paleo-climatic proxy record, was used to analyze the Holocene climate changes in the local region. The proxy record was established in the Sanjiaocheng (SJC), Triangle Town in Chinese, Section (103°20′25″E, 39°00′38″N), which is located at the northwestern boundary of the present Asian summer monsoon in China, and is sensitive to global environmental and climate changes. Applying singular spectrum analysis (SSA) to the TOC series, principal climatic oscillations and periodical changes were studied. The results reveal 3 major patterns of climate change regulated by reconstructed components (RCs). The first pattern is natural long-term trend of climatic change in the local area (Minqin Basin), indicating a relatively wetter stage in early Holocene (starting at 9.5 kaBP), and a relatively dryer stage with a strong lake desiccation and a declined vegetation cover in mid-Holocene (during 7–6 kaBP). From 4.0 kaBP to the present, there has been a gradually decreasing trend in the third reconstructed component (RC3) showing that the local climate changed again into a dryer stage. The second pattern shows millennial-centennial scale oscillations containing cycles of 1 600 and 800 years that have been present throughout almost the entire Holocene period of the last 10 000 years. The third pattern is a millennial-centennial scale variation with a relatively smaller amplitude and unclear cycles showing a nonlinear interaction within the earth’s climate systems.展开更多
Baoxinggou area is located in northern Daxing'anling. In this area,comprehensive use of geophysical and geochemical exploration methods plays an important role in the prospecting,and has yielded some application r...Baoxinggou area is located in northern Daxing'anling. In this area,comprehensive use of geophysical and geochemical exploration methods plays an important role in the prospecting,and has yielded some application results so far. Based on the 1 /100 000 stream sediment anomaly survey,the methods of 1 /20 000 soil geochemical measurement,trenching engineering on the earth's surface and 1 /10 000 IP intermediate gradient survey were all used to verify and decompose drainage anomalies,as well as to find and locate ore bodies. In this way,an effective,economical and quick prospecting method was concluded,which focuses on the middle and lower mountain forest swamp landscape in the northern part of Daxing'anling,and provides reference for the prospecting in the area.展开更多
基金Supported by the National Natural Science Foundation of China(41261062)Key Science and Technology Project of Hainan(ZDXM20130021)~~
文摘This study was conducted to reveal the vertical distribution and concentration variation of heavy metals（Cr, Co, Ni, Cu, Zn, As, Cd and Pb） in the mangrove sediments of Dongzhai Harbor, Hainan by using inductively-coupled plasma mass spectrometry（ICP-MS）. The surface sediment samples were collected from 15 sites, and a geoaccumulation index（Igeo） was estimated to quantify the pollution status of the mangrove sediments. The results showed that the concentrations of heavy metals in sediments followed the order of Cr〉 Zn〉 Ni〉 Cu 〉Pb 〉Co〉 Cd. A common pattern was found in some heavy metals（Cu, Zn, As and Pb） as their concentrations were significantly and negatively correlated with depth. Cr concentration in upper layer was slightly lower than that in middle and lower layers,while the concentrations of Ni and Cd in middle layer were slightly higher than in upper and lower layers. The geoaccumulation index indicated that the surface sediments at sites QT-1-01, QT-1-02, QT-2, GN-1, GN-2 and GN-3 were strongly polluted by Cd, and unpolluted to moderately polluted or moderately polluted by As.
基金the National Natural Science Foundation of China (NSFC) (No. 40571169)the NSFC’s Innovation Team Project (No. 40421101), and the NSFC’s Key Program Project (No. 90502008)
文摘The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57′–104°57′E, 37°48′–39°17′N) in northwestern China, which has a 10 000-year-long paleo-climatic proxy record, was used to analyze the Holocene climate changes in the local region. The proxy record was established in the Sanjiaocheng (SJC), Triangle Town in Chinese, Section (103°20′25″E, 39°00′38″N), which is located at the northwestern boundary of the present Asian summer monsoon in China, and is sensitive to global environmental and climate changes. Applying singular spectrum analysis (SSA) to the TOC series, principal climatic oscillations and periodical changes were studied. The results reveal 3 major patterns of climate change regulated by reconstructed components (RCs). The first pattern is natural long-term trend of climatic change in the local area (Minqin Basin), indicating a relatively wetter stage in early Holocene (starting at 9.5 kaBP), and a relatively dryer stage with a strong lake desiccation and a declined vegetation cover in mid-Holocene (during 7–6 kaBP). From 4.0 kaBP to the present, there has been a gradually decreasing trend in the third reconstructed component (RC3) showing that the local climate changed again into a dryer stage. The second pattern shows millennial-centennial scale oscillations containing cycles of 1 600 and 800 years that have been present throughout almost the entire Holocene period of the last 10 000 years. The third pattern is a millennial-centennial scale variation with a relatively smaller amplitude and unclear cycles showing a nonlinear interaction within the earth’s climate systems.
基金Supported by project of Special Service Funds for Gold Geology of Gold Headquarters(2008,No.20130301)
文摘Baoxinggou area is located in northern Daxing'anling. In this area,comprehensive use of geophysical and geochemical exploration methods plays an important role in the prospecting,and has yielded some application results so far. Based on the 1 /100 000 stream sediment anomaly survey,the methods of 1 /20 000 soil geochemical measurement,trenching engineering on the earth's surface and 1 /10 000 IP intermediate gradient survey were all used to verify and decompose drainage anomalies,as well as to find and locate ore bodies. In this way,an effective,economical and quick prospecting method was concluded,which focuses on the middle and lower mountain forest swamp landscape in the northern part of Daxing'anling,and provides reference for the prospecting in the area.
