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Dou, Yanguang; Yang, Shouye; Liu, Zhenxia; Clift, Peter D.; Yu, Hua; Berne, Serge; Shi, Xuefa. |
The Okinawa Trough is a natural laboratory for the study of later Quaternary land-ocean interaction and paleoenvironmental changes. In this study we reconstruct the evolution of clay mineral assemblages in Core DGKS9604 retrieved from the central Okinawa Trough. Illite dominates the clay mineral compositions, with average contents above 60%. Clay mineral evolution since 28 ka is closely related to changes in sediment provenance and paleoenvironment. Sea level rise and the strength of the Kuroshio Current control the dispersal and deposition of clays on the East China Sea shelf and in the Okinawa Trough, and thus, determine the clay mineral compositions in the core sediments. During the late last glacial period (28.0-14.0 ka), the paleo-Changjiang River... |
Tipo: Text |
Palavras-chave: Clay mineral; Sediment; Provenance; East China Sea; Okinawa Trough. |
Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00002/11367/7977.pdf |
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Chaves,Lúcia Helena Garófalo; Tit,Gilvanise Alves. |
Reactions of heavy metals with clay minerals are important in determining metal fates in the environment. However, the adsorption process of these metals by the bentonite has been extensively investigated. The objectives of this work were to assess the ability of bentonite clay to adsorb cadmium and copper and to study the effects of pH and particle size upon these metals adsorption. Adsorption isotherms were obtained from batch adsorption experiments, with increasing cadmium and copper concentrations (5-200 mg L-1). To find out the effects of pH and particle size on adsorption, the experiments were conducted at pH 4; 5 and 6 using particles sizes of < 0.5 mm and 0.5 to 2.0 mm . The difference between initial and final cadmium and copper concentrations... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Clay mineral; Heavy metals; Isotherms; Langmuir. |
Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902011000200004 |
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FARIA,MARCIA DE MELO; SANCHEZ,BRAZ A.. |
Geochemical and clay mineralogical studies of bottom sediments collected along the Macacu and Caceribu rivers and Guanabara Bay were carried out in order to investigate the relationship between major source areas and recent sediments of the bay. Clay mineralogy includes different groups with selective distribution conditioned by geomorphic features and depositional settings. Micaceous clay minerals are abundant near parent rock in the upper course, whereas kaolinite derived from varied sources is gradually concentrated towards the estuary. In the Guanabara Bay, kaolinite accumulates near river mouths, while micaceous clay minerals are converted into mixed layers in the estuary. Analyses of heavy metal contents reveal higher levels of Zn and Cu in sediments... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heavy metal; Clay mineral; Sediment; Guanabara Bay. |
Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652001000100010 |
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