Surficial sediments of the wave-dominated Orange River Delta and the adjacent continental margin off south-western Africa

 

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dc.contributor.author Rogers, J
dc.contributor.author Rau, A J Rua
dc.date.accessioned 2017-03-16T13:18:42Z
dc.date.available 2017-03-16T13:18:42Z
dc.date.issued 2006
dc.identifier http://dx.doi.org/10.2989/18142320609504202
dc.identifier.citation Rogers, J., & Rau, A. J. (2006). Surficial sediments of the wave-dominated Orange River Delta and the adjacent continental margin off south-western Africa. African Journal of Marine Science, 28(3-4), 511-524.
dc.identifier.uri http://hdl.handle.net/11427/24052
dc.description.abstract The textural and compositional characteristics of the surficial shelf sediments north and south of the Orange River Delta are reviewed and compared. Sediments are fractionated and dispersed both north- and southwards of the Orange River mouth by wave action, longshore drift and subsurface currents. The mean grain size decreases both offshore and southwards in response to decreased wave influence at the seabed and the competence of the weak poleward undercurrent respectively. The increasing dominance of marine biogenic components in sediments south of the prodelta indicates a greater marine influence, modifying previous inferences that the Namaqualand mudbelt is primarily derived from the southward transport of Orange River sediments. A sharp distinction can be drawn between sediments of the Orange Shelf to the south and the Walvis Shelf to the north. Foraminiferarich deposits that dominate the Orange middle shelf and slope indicate that upwelling is an inner-shelf phenomenon. On the Walvis Shelf, foraminiferal sediments are confined to the slope and outer shelf. Fish debris is more common in Walvis Shelf sediments. Although phosphorite and glauconite sands often occur together in the same deposits on the Orange Shelf, the two minerals are concentrated in separate deposits on the Walvis Shelf.
dc.language.iso eng
dc.source African Journal of Marine Science
dc.source.uri http://www.tandfonline.com/toc/tams20/current
dc.subject.other Orange River Delta
dc.subject.other Orange Shelf
dc.subject.other Surficial Sediments
dc.subject.other Walvis Shelf
dc.title Surficial sediments of the wave-dominated Orange River Delta and the adjacent continental margin off south-western Africa
dc.type Journal Article en_ZA
dc.date.updated 2016-01-19T07:08:02Z
uct.type.publication Research en_ZA
uct.type.resource Article en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Geological Sciences en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Rogers, J., & Rau, A. J. R. (2006). Surficial sediments of the wave-dominated Orange River Delta and the adjacent continental margin off south-western Africa. <i>African Journal of Marine Science</i>, http://hdl.handle.net/11427/24052 en_ZA
dc.identifier.chicagocitation Rogers, J, and A J Rua Rau "Surficial sediments of the wave-dominated Orange River Delta and the adjacent continental margin off south-western Africa." <i>African Journal of Marine Science</i> (2006) http://hdl.handle.net/11427/24052 en_ZA
dc.identifier.vancouvercitation Rogers J, Rau AJR. Surficial sediments of the wave-dominated Orange River Delta and the adjacent continental margin off south-western Africa. African Journal of Marine Science. 2006; http://hdl.handle.net/11427/24052. en_ZA
dc.identifier.ris TY - Journal Article AU - Rogers, J AU - Rau, A J Rua AB - The textural and compositional characteristics of the surficial shelf sediments north and south of the Orange River Delta are reviewed and compared. Sediments are fractionated and dispersed both north- and southwards of the Orange River mouth by wave action, longshore drift and subsurface currents. The mean grain size decreases both offshore and southwards in response to decreased wave influence at the seabed and the competence of the weak poleward undercurrent respectively. The increasing dominance of marine biogenic components in sediments south of the prodelta indicates a greater marine influence, modifying previous inferences that the Namaqualand mudbelt is primarily derived from the southward transport of Orange River sediments. A sharp distinction can be drawn between sediments of the Orange Shelf to the south and the Walvis Shelf to the north. Foraminiferarich deposits that dominate the Orange middle shelf and slope indicate that upwelling is an inner-shelf phenomenon. On the Walvis Shelf, foraminiferal sediments are confined to the slope and outer shelf. Fish debris is more common in Walvis Shelf sediments. Although phosphorite and glauconite sands often occur together in the same deposits on the Orange Shelf, the two minerals are concentrated in separate deposits on the Walvis Shelf. DA - 2006 DB - OpenUCT DP - University of Cape Town J1 - African Journal of Marine Science LK - https://open.uct.ac.za PB - University of Cape Town PY - 2006 T1 - Surficial sediments of the wave-dominated Orange River Delta and the adjacent continental margin off south-western Africa TI - Surficial sediments of the wave-dominated Orange River Delta and the adjacent continental margin off south-western Africa UR - http://hdl.handle.net/11427/24052 ER - en_ZA


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