Sedimentological and geochemical evidence for late quaternary environmental changes in southern Africa : a case study of the mudbelt deposits off Namaqualand

This thesis is comprised of sedimentological and geochemical studies of seven 7m core sediments retrieved from the Namaqualand Mudbelt, South Africa. The purpose of this research is to contribute to the evidence for environmental change during the late Quaternary in the southern Africa from the analyses of continental shelf sediments and more specifically, to examine feasibility of using Namaqualand mudbelts as a key to understanding late environmental dynamics of both terrestrial and marine environment. Namaqualand mudbelts seem to have been deposited during the last 10 000 years. Chrono- and lithostratigraphy, coarse-fraction and geochemical analyses suggest the following sedimentary development on the Namaqualand offshore. An early period of deposition dominated by marine conditions off the coast, but with significant input in the north (Orange Delta) and south (off KIeinsee). There is a fining upcore sequence from the Orange Prodelta southward to the inner shelf (off Kleinsee). This fining-upward sequence is generally indicative of shoreward transgression of the sea (rising sea-level). As sea-level rises (shoreward transgression), finer-grained deeper water deposits migrate landward and are deposited over shallower water deposits. While the Orange River might be a major source of sediments on the Orange River Delta, marine contribution is increasingly important far south of the Orange Delta (off KIeinsee). ln addition, berg winds and local ephemeral Namaqualand rivers are also increasingly important.

Grantor dc:publisher.institution

Department of Environmental and Geographical Science

Year dc:date.issued

1997

Author dc:creator

• Mabote, Molefi Elliot

Advisors dc:contributor.advisor

• Meadows, Michael E
• Rogers , J

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/13887

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/13887