High-resolution bathymetry and shallow acoustic images of current-controlled sedimentary processes in the Southern Mozambique Channel

• Main Authors: Breitzke, Monika, Jokat, Wilfried, Krocker, Ralf, Watkeys, M., Wiles, E.
• Format: Conference Object
• Language: unknown
• Published: 2011
• Subjects: Antarc*; Antarctic; NADW; North Atlantic Deep Water; North Atlantic
• Online Access: https://epic.awi.de/id/eprint/23583/; https://hdl.handle.net/10013/epic.36479

The Mozambique Basin and Mozambique Channel are one of the key areas in the Southwest Indian Ocean, where ocean currents are considered to generate a highly variable microtopography on the sea floor. The Antarctic Bottom Water (AABW) and the North Atlantic Deep Water (NADW) flowing northward along the southeast African margin and returning southward along the west Madagascan margin are the dominant bottom currents. The Mozambique Current (MC) flowing southward along the southeast African margin, the East Madagascar Current (EMC) surrounding the southern tip of Madagascar and the southward flowing Agulhas Current (AC) formed by the confluence of the former two currents off southeast Africa are the dominant surface currents. Pronounced eddies traveling southward through the Mozambique Channel additionally contribute to the surface circulation.During the R/V Sonne cruise SO-183 a rectangular grid (500 km x 700 km) of high-resolution multibeam sonar and parametric subbottom profiler data was collected in the Southern Mozambique Channel, which allows to study both the orientation and lateral extension of the current-controlled submarine bedforms and the shallow acoustic subsurface structures. Generally, this data set illustrates, that factors such as the large-scale morphology, the sediment supply from southeast Africa and Madagascar, the sediment transport and sorting via the Zambesi Channel and external forces like the Coriolis force play an important role in the generation, distribution, shape and size of the submarine bedforms. Based on the multibeam bathymetry several microtopographic zones ranging from a flat sea floor over large- and small-scale sinusoidal bedforms to rough, irregular, erosional features are defined to classify the study area. An additional inspection of the subbottom profiler data allows a further detailed description and subdivision of the microtopographic zones. For instance, both the northwestern and the southeastern part of the study area are characterized by a flat sea floor. But in the ...