Sediment dynamics on the narrow,canyon-incised and current-swept shelf of the northern KwaZulu-Natal continental shelf,South Africa |
| |
| Authors: | Andrew Green |
| |
| Institution: | (1) Joint Council for Geoscience-University of KwaZulu-Natal, Marine Geoscience Unit, School of Geological Sciences, University of KwaZulu-Natal, Private Bag X54001, Westville, Durban, 4000, South Africa |
| |
| Abstract: | Side-scan sonar, multibeam bathymetry, ShipekTM grab, and high- to moderate-resolution sub-bottom data for the northern KwaZulu-Natal continental shelf reveal further insights
into the interactions between sediment dynamics, strong western boundary currents and submarine canyon topography. Unlike
previously recognised mechanisms for bedload parting on current-swept shelves, bedload partings here are the result of complex
interactions between the western boundary poleward-flowing Agulhas Current and submarine canyon topography. This has resulted
in bedforms orientated orthogonally to the canyon axis, with sediments entrained equator-wards into the canyon heads before
resuming their dominant southerly migration. It is in these zones of parting where the most prominent bedforms occur; these
bedform fields are formed by positive feedback in the boundary layer between an increasingly undulatory Agulhas Current and
a seafloor incised by regularly spaced submarine canyons. Bedform morphometrics such as wavelength–height, depth–height and
distance from thalweg–height relationships show no distinct patterns, indicating that the bedforms are heavily reworked and
appear to be out of equilibrium with the inherent oceanographic conditions. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
