A new pathway for Deep water exchange between the Natal Valley and Mozambique Basin?

Wiles, Errol; Green, Andrew N.; Watkeys, M. K.; Jokat, Wilfried; Krocker, Ralf

doi:10.1007/s00367-014-0383-1

Cited by 15 publications

(9 citation statements)

References 92 publications

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“…Despite the strong influence that circulation exerts on sedimentary processes (e.g., Wiles et al, 2014Wiles et al, , 2017Breitzke et al, 2017), long stretches of the East African continental margin have not been interpreted in terms of their depositional processes. This paper presents novel analysis of water mass influence on seafloor morphology to interpret CDSs along the East African continental margin between the latitudes of 15° S and 30° S (hereafter the Mozambique Channel).…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Contourite depositional systems along the Mozambique channel: The interplay between bottom currents and sedimentary processes

Thiéblemont

Hernández-Molina

Miramontes

et al. 2019

Deep Sea Research Part I: Oceanographic Research Papers

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We present a combined study of the geomorphology, sedimentology, and physical oceanography of the Mozambique Channel to evaluate the role of bottom currents in shaping the Mozambican continental margin and adjacent Durban basin. Analysis of 2D multichannel seismic reflection profiles and bathymetric features revealed major contourite deposits with erosive (abraded surfaces, contourite channels, moats, furrows and scours), depositional (plastered and elongated-mounded drifts, sedimentary waves), and mixed (terraces) features, which were then used to construct a morphosedimentary map of the study area. Hydrographic data and hydrodynamic modelling provide new insights into the distribution of water masses, bottom current circulation and associated processes (e.g., eddies, internal waves, etc.) occurring along the Mozambican slope, base-of-slope and basin floor. Results from this work represent a novel deep-sea sedimentation model for the Mozambican continental margin and adjacent Durban basin. This model shows 1) how bottom circulation of water masses and associated sedimentary processes shape the continental margin, 2) how interface positions of watermasses with contrasting densities (i.e., internal waves) sculpt terraces along the slope at a regional scale, and 3) how morphologic obstacles (seamounts, Mozambique Ridge, etc.) play an essential role in local water mass behaviours and dynamics. Further analysis of similar areas can expand understanding of the global role of bottom currents in deep-sea sedimentation. Highlights► Combined study of the geomorphology, sedimentology, and physical oceanography of the Mozambique Channel. ► Bottom circulation of water masses and associated sedimentary processes shape the continental margin. ► Interface positions of water-masses with contrasting densities (i.e., internal waves) sculpt terraces along the slope at a regional scale. ► Morphologic obstacles play an essential role in local water mass behaviours and dynamics.

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Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Contourite depositional systems along the Mozambique channel: The interplay between bottom currents and sedimentary processes

Thiéblemont

Hernández-Molina

Miramontes

et al. 2019

Deep Sea Research Part I: Oceanographic Research Papers

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“…Deeper circulation flows northward along the western margin of the Channel and is driven by the Mozambique Undercurrent (MUC) and Antarctic Bottom Water (AABW) ( Fig. 2) (De Ruijter et al, 2002;Wiles et al, 2014). The MUC includes the Antarctic Intermediate Water (AAIW) between 800 m and 1500 m and the North Atlantic Deep Water (NADW) from 2000 m to 3500 m depth.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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

et al. 2019

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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. Highlights ► The Zambezi turbidite system comprises a channelized fan and a semi-confined fan. ► The Zambezi Valley has an atypical morphology compared to other turbidite systems. ► Erosional processes dominate in the valley. ► From echo facies, deposition appears mainly fine-grained in the semiconfined fan. ► Oceanic and turbidity currents control sediment distribution and erosion.

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“…In addition to the landforms of geological origin, the swIOBC also reveals a plethora of sedimentological landforms. Sediment waves, scours, sediment ridges, and drifts occur (Figures and a–3c) providing information on the interactions of bottom currents on the seafloor over prolonged periods of time indicating areas of erosion, lateral sediment‐transport, and deposition (Stow et al, ; Uenzelmann‐Neben, ; Uenzelmann‐Neben & Huhn, ; Uenzelmann‐Neben et al, ; Wiles et al, ). These landforms have already been described and interpreted by Breitzke et al () for Mozambique Channel linking them to the flow paths of Antarctic Bottom Water and North Atlantic Deep Water as part of the meridional overturning circulation (Breitzke et al, ; Sultan et al, ).…”

Section: Resultsmentioning

confidence: 99%

The Southwest Indian Ocean Bathymetric Compilation (swIOBC)

Dorschel

Jensen

Arndt

et al. 2018

Geochem Geophys Geosyst

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We present a comprehensive regional bathymetric data compilation for the southwest Indian Ocean (swIOBC) covering the area from 4°S to 40°S and 20°E to 45°E with a spatial resolution of 250 m. For this, we used multibeam and singlebeam data as well as data from global bathymetric data compilations. We generated the swIOBC using an iterative approach of manual data cleaning and gridding, accounting for different data qualities and seamless integration of all different kinds of data. In comparison to existing bathymetric charts of this region, the new swIOBC benefits from nearly four times as many data‐constrained grid cells and a higher resolution, and thus reveals formerly unseen seabed features. In the central Mozambique Basin a surprising variety of landscapes were discovered. They document a deep reaching influence of the Mozambique Current eddies. Details of the N‐S trending Zambezi Channel could be imaged in the central Mozambique Basin.

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A new pathway for Deep water exchange between the Natal Valley and Mozambique Basin?

Cited by 15 publications

References 92 publications

Contourite depositional systems along the Mozambique channel: The interplay between bottom currents and sedimentary processes

Contourite depositional systems along the Mozambique channel: The interplay between bottom currents and sedimentary processes

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

The Southwest Indian Ocean Bathymetric Compilation (swIOBC)

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