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

dc.contributor.authorRogers, J
dc.contributor.authorRau, A J Rua
dc.date.accessioned2017-03-16T13:18:42Z
dc.date.available2017-03-16T13:18:42Z
dc.date.issued2006
dc.date.updated2016-01-19T07:08:02Z
dc.description.abstractThe 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.identifierhttp://dx.doi.org/10.2989/18142320609504202
dc.identifier.apacitationRogers, 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/11427/24052en_ZA
dc.identifier.chicagocitationRogers, 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/11427/24052en_ZA
dc.identifier.citationRogers, 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.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
dc.identifier.urihttp://hdl.handle.net/11427/24052
dc.identifier.vancouvercitationRogers 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.language.isoeng
dc.publisher.departmentDepartment of Geological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.sourceAfrican Journal of Marine Science
dc.source.urihttp://www.tandfonline.com/toc/tams20/current
dc.subject.otherOrange River Delta
dc.subject.otherOrange Shelf
dc.subject.otherSurficial Sediments
dc.subject.otherWalvis Shelf
dc.titleSurficial sediments of the wave-dominated Orange River Delta and the adjacent continental margin off south-western Africa
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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