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| Thiéblemont, Antoine; Hernández-molina, F. Javier; Miramontes, Elda; Raisson, François; Penven, Pierrick. |
| 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 morpho-sedimentary 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... |
| Tipo: Text |
Palavras-chave: Contourites; Bottom currents; Sedimentary processes; Water mass interfaces; Continental margin; Mozambique channel. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00488/60002/63238.pdf |
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| Miramontes, Elda; Jorry, Stephan; Jouet, Gwenael; Counts, John; Courgeon, Simon; Roy, Philippe; Guerin, Charline; Hernández-molina, F. Javier. |
| Subaqueous sand dunes are common bedforms on continental shelves dominated by tidal and geostrophic currents. However, much less is known about sand dunes in deep‐marine settings that are affected by strong bottom currents. In this study, dune fields were identified on drowned isolated carbonate platforms in the Mozambique Channel (south‐west Indian Ocean). The acquired data include multibeam bathymetry, multi‐channel high‐resolution seismic reflection data, sea floor imagery, a sediment sample and current measurements from a moored current meter and hull‐mounted acoustic Doppler current profiler. The dunes are located at water depths ranging from 200 to 600 m on the slope terraces of a modern atoll (Bassas da India Atoll) and within small depressions... |
| Tipo: Text |
Palavras-chave: Bedform; Bottom currents; Contourite; Deep-marine environment; Eddy; Geostrophic current; Oceanic circulation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00472/58418/60989.pdf |
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| Miramontes Garcia, Elda; Garreau, Pierre; Caillaud, Matthieu; Jouet, Gwenael; Pellen, Romain; Hernández-molina, F. Javier; Clare, Michael A.; Cattaneo, Antonio. |
| Contourites are common morphological features along continental margins where currents encounter the seafloor. They can provide long-term archives of palaeoceanography, may be prone to sediment instability, and can have a great potential for hydrocarbon exploration. Despite their importance and increasingly recognised ubiquitous occurrence worldwide, the link between oceanographic processes and contourite features is poorly constrained. In particular, it is unclear under which specific conditions sediments are mobilised, modified and deposited by bottom currents. Here, we aim to determine key bottom current characteristics (velocity and bottom shear stress) affecting contourite deposition, by assuming that recent oceanographic regimes may be extended back... |
| Tipo: Text |
Palavras-chave: Sediment drift; Erosion; Oceanic circulation; Bottom shear stress. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00483/59426/62241.pdf |
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