Contourite and mixed turbidite-contourite systems in the Mozambique Channel (SW Indian Ocean): Link between geometry, sediment characteristics and modelled bottom currents

Type Article
Date 2021-07
Language English
Author(s) Miramontes Elda1, 2, Thiéblemont Antoine3, 4, Babonneau Nathalie9, Penven Pierrick6, Raisson François3, Droz Laurence5, Jorry StephanORCID7, Fierens Ruth5, Counts John W.8, Wilckens Henriette1, 2, Cattaneo AntonioORCID7, Jouet Gwenael7
Affiliation(s) 1 : Faculty of Geosciences, University of Bremen, Bremen 28359, Germany
2 : MARUM-Center for Marine Environmental Sciences, University of Bremen, Bremen 28359, Germany
3 : TOTAL, R&D Frontier Exploration Program, Avenue Larribau, Pau 64000, France
4 : Department of Earth Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK
5 : UMR 6538 CNRS-UBO, IUEM, Laboratoire Géosciences Océan, Plouzané 29280, France
6 : UMR 6523 CNRS, IFREMER, IRD, UBO, Laboratoire d'Océanographie Physique et Spatiale, Plouzané, France
7 : IFREMER, Géosciences Marines, Plouzané 29280, France
8 : USGS Eastern Energy Resources Science Center, MS 956, Reston, VA, USA
9 : UMR 6538 CNRS-UBO, IUEM, Laboratoire Géosciences Océan, Plouzané 29280, France
Source Marine Geology (0025-3227) (Elsevier BV), 2021-07 , Vol. 437 , P. 106502 (20p.)
DOI 10.1016/j.margeo.2021.106502
WOS© Times Cited 21
Keyword(s) Bottom current, Contour current, Oceanic circulation, Deep-water environment, Sediment drift, Contourite depositional system
Abstract

Oceanic currents can profoundly reshape the seafloor and even modify the characteristics of turbidite systems. Multiple erosional and depositional features directly formed by bottom currents (i.e. contourites), as well as by the interaction between bottom currents and turbidity currents or turbidite systems (i.e. mixed turbidite-contourite systems) have been identified in the Mozambique Channel (SW Indian Ocean) in multibeam bathymetry, seismic reflection data, sub-bottom profiler images and sediment cores. In this study, we characterise the morphology, stacking pattern and sedimentary characteristics of these sedimentary systems, and analysed the properties of bottom currents at these systems using a hydrodynamic numerical model. Modelled bottom currents are the highest at abraded surfaces and moats, but they also display a relatively high variability, suggesting that the observed erosion is not the result of a constant or persistent current but rather of episodes of intense circulation. Modelled bottom currents at contourite terraces are not significantly different from currents at related plastered drifts, where accumulation is enhanced. The formation of contourite terraces can thus not solely be explained by the mean oceanic circulation and eddies, implying that other processes such as internal waves may play a relevant role in their formation. Three different types of mixed turbidite-contourite systems were observed: one characterised by asymmetric channel-levee systems formed by the synchronous interaction of bottom currents and turbidity currents, one characterised by a phased interaction that resulted in the erosion of the channel flanks by bottom currents, and another one in which both synchronous and phased interaction played a relevant role in the evolution of the system. Finally, we propose a simplified classification of contourites that can be applied to any contourite system worldwide, and that comprises erosional and depositional features, including muddy and sandy contourite deposits.

Full Text
File Pages Size Access
Author's final draft 70 51 MB Open access
20 27 MB Access on demand
Top of the page

How to cite 

Miramontes Elda, Thiéblemont Antoine, Babonneau Nathalie, Penven Pierrick, Raisson François, Droz Laurence, Jorry Stephan, Fierens Ruth, Counts John W., Wilckens Henriette, Cattaneo Antonio, Jouet Gwenael (2021). Contourite and mixed turbidite-contourite systems in the Mozambique Channel (SW Indian Ocean): Link between geometry, sediment characteristics and modelled bottom currents. Marine Geology, 437, 106502 (20p.). Publisher's official version : https://doi.org/10.1016/j.margeo.2021.106502 , Open Access version : https://archimer.ifremer.fr/doc/00693/80472/