Late Quaternary geomorphology and sedimentary processes in the Zambezi turbidite system (Mozambique Channel)

Type Article
Date 2019-06
Language English
Author(s) Fierens Ruth1, Droz Laurence1, Toucanne SamuelORCID2, Raisson François3, Jouet Gwenael2, Babonneau Nathalie4, Miramontes Garcia Elda1, Landurain Steven4, Jorry StephanORCID2
Affiliation(s) 1 : IUEM-UBO-CNRS, UMR6538, Laboratoire Géosciences Océan, 29280 Plouzané, France
2 : IFREMER Centre Bretagne, Unité de Recherche Géosciences Marines, 29280 Plouzané, France
3 : Total, Centre Scientifique et Technique Jean Féger, 64000 Pau, France
Source Geomorphology (0169-555X) (Elsevier BV), 2019-06 , Vol. 334 , P. 1-28
DOI 10.1016/j.geomorph.2019.02.033
WOS© Times Cited 8
Keyword(s) Zambezi turbidite system, Late Quaternary, Multibeam bathymetry, Sub-bottom seismic profiles
Abstract

The morphology and present-day sediment distribution of the Zambezi turbidite system was investigated using new bathymetric and sub-bottom profiler data as part of the PAMELA research project. The Zambezi turbidite system is composed of two depositional systems: a channelized fan (the Zambezi Fan) and a semi-confined fan (in the lntermediate Basin). The Zambezi Fan includes the Zambezi Valley, which is deeply incised in the Mozambique Channel and is more than three times as large and deep as the great Tanzanian and North Atlantic Mid-Ocean channels. The erosion in the Zambezi Valley is evidenced by its V-shaped morphology and the existence of a U-shaped thalweg affected by several generations of incisions. Based on echo facies and cores from literature, sediments of the Zambezi Fan are dominantly coarse-grained and fine-grained overbank deposits are infrequent. The distal portion of the Zambezi Fan is a main depositional area where typical transparent wedged-shape seismic bodies are interpreted as terminal lobes. Seismic facies in the Intermediate Basin are thought to represent mostly fine-grained turbidites intercalated with infrequent coarse-grained sheet-like turbidites. Hydrodynamic circulation (from surface eddies to the deep circulation of NADW) appears to have a great impact on the Mozambique Channel sedimentation and is suggested (1) to be involved in the delivery of the Zambezi River sediments along the Mozambique margin, (2) to entrain the upper suspended load of turbidity currents, contributing to the absence of fine-grained sedimentation and (3) to contribute to the erosion of the valley flanks leading to the exceptionally great dimensions of the valley.

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Fierens Ruth, Droz Laurence, Toucanne Samuel, Raisson François, Jouet Gwenael, Babonneau Nathalie, Miramontes Garcia Elda, Landurain Steven, Jorry Stephan (2019). Late Quaternary geomorphology and sedimentary processes in the Zambezi turbidite system (Mozambique Channel). Geomorphology, 334, 1-28. Publisher's official version : https://doi.org/10.1016/j.geomorph.2019.02.033 , Open Access version : https://archimer.ifremer.fr/doc/00483/59425/