Detailed knowledge of shelf bathymetry is essential for understanding the long-term geological evolution of continental margins, the extent of the coastal plain as the shoreline moved in response to Pleistocene sea-level fluctuations, and for ecosystems management, resource exploration, and navigation. Although some areas have been mapped in detail, most South African shelf bathymetry is poorly resolved. This paper presents a bathymetric map of the South African continental shelf derived from digital single-beam echo-sounding data collected by the Department of Agriculture, Forestry and Fisheries (DAFF) that is at a significantly higher resolution than was previously available as presented by Dingle et al. (Annals of the South African Museum 98:1-27, 1987). The bathymetric dataset consists of approximately 7 million data sonar points collected by the Fisheries Division of DAFF over the last two decades, covering the entire South African continental shelf area of 541,000 km(2) between the Orange River mouth on the West Coast and Kosi Bay on the East Coast. The new map not only resolves known shelf bathymetric features in greater detail but also reveals new features. The origin of some bathymetric features remains unknown, but many appear to relate to bedrock geology, sediment deposition (river drainage systems and ocean currents), and sea-level fluctuations.
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