Contourite on the Limpopo Corridor, Mozambique margin: Long‐term evolution, facies distribution and Plio‐Quaternary processes

Type Article
Acceptance Date 2022-09-30 IN PRESS
Language English
Author(s) Babonneau NathalieORCID1, Raisson FrançoisORCID2, Genêt Adrien1, Lopes Ugo1, Fierens Ruth1, Miramontes EldaORCID3, 4, Révillon SidonieORCID1, 5, Rabineau MarinaORCID7, Droz Laurence1, Belleney Deborah6, 8, Moulin Maryline, Aslanian DanielORCID8
Affiliation(s) 1 : UMR 6538 GEO‐OCEAN, Univ Brest, CNRS, Ifremer, Univ. Bretagne‐Sud 29280 Plouzané ,France
2 : TotalEnergies, CSTJF, Avenue Larribau 64000 Pau ,France
3 : MARUM‐Center for Marine Environmental Sciences University of Bremen Bremen 28359, Germany
4 : Faculty of Geosciences University of Bremen Bremen 28359 ,Germany
5 : SEDISOR, place N. Copernic 29280 Plouzané, France
6 : UMR 6554, LETG Littoral, Environnement, Télédétection, Géomatique UMR 6554, Institut Universitaire Européen Mer, UBO, Place Copernic 29280 Plouzané ,France
7 : UMR 6538 GEO‐OCEAN, Univ Brest, CNRS, Ifremer, Univ. Bretagne‐Sud 29280 Plouzané ,France
8 : UMR 6538 GEO‐OCEAN, Univ Brest, CNRS, Ifremer, Univ. Bretagne‐Sud 29280 Plouzané ,France
Source Sedimentology (0037-0746) (Wiley) In Press
DOI 10.1111/sed.13045
Keyword(s) Bottom current, calcarenite, contourite, drift, moat, Mozambique
Abstract

Bottom currents are key processes that contribute to the shaping of submarine slopes, with the redistribution of sediments in contourite systems. Despite numerous recent studies on contourite systems, the complexity and diversity of these sedimentary systems are still not fully understood and often underestimated. Their understanding requires comprehensive works integrating all scales from seismic architecture to microfacies. This paper focuses on a contouritic ridge located between 2000 m and 2500 m water depth on the Mozambique margin. Bathymetry, seismic data and piston cores collected during the PAMELA-MOZ3 cruise allow a multi-scale study from large depositional geometries to sedimentary facies. At the seismic scale, the contouritic ridge show three stages of evolution with: (i) initiation and development of the drift/moat system; (ii) an intermediate stage with successive incisions and aggradations; and (iii) moat infill and drift erosion during the Plio-Quaternary. Plio-Quaternary deposits are composed of hemipelagic, turbiditic and contouritic facies filling the moat. Coarse-grained contouritic facies, dominated by planktonic foraminifera, are identified on the western flank of the ridge between the moat infill and the erosional area at the top of the ridge. They consist of condensed deposits, with sedimentation rate about 0.3 cm/ka, indicating a strong and stable bottom current that winnows away the fine-grained component. This facies could be present more generally in intermediate position between erosion and depositional areas in contourite systems. At present, the contourite system is located at the transition depth between North Atlantic Deep Water and Antarctic Intermediate Water. Trajectories of bottom currents are complex and interact with sporadic turbidity currents and anti-clockwise eddies that participate in reshaping the sea floor morphology. Although Plio-Quaternary depositional geometries indicate the end of drift/moat development, the moat filling and drift erosion are also related to bottom currents and constitute atypical contouritic sedimentation.

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Babonneau Nathalie, Raisson François, Genêt Adrien, Lopes Ugo, Fierens Ruth, Miramontes Elda, Révillon Sidonie, Rabineau Marina, Droz Laurence, Belleney Deborah, Moulin Maryline, Aslanian Daniel Contourite on the Limpopo Corridor, Mozambique margin: Long‐term evolution, facies distribution and Plio‐Quaternary processes. Sedimentology IN PRESS. Publisher's official version : https://doi.org/10.1111/sed.13045 , Open Access version : https://archimer.ifremer.fr/doc/00795/90745/