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| Registros recuperados: 12 | |
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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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| Courgeon, Simon; Jorry, Stephan; Jouet, Gwenael; Camoin, G.; Boudagher-fadel, M. K.; Bachelery, P.; Caline, B.; Boichard, R.; Revillon, Sidonie; Thomas, Yannick; Thereau, Estelle; Guerin, Charline. |
| Understanding the impact of tectonic activity and volcanism on long-term (i.e. millions years) evolution of shallow-water carbonate platforms represents a major issue for both industrial and academic perspectives. The southern central Mozambique Channel is characterized by a 100 km-long volcanic ridge hosting two guyots (the Hall and Jaguar banks) and a modern atoll (Bassas da India) fringed by a large terrace. Dredge sampling, geophysical acquisitions and submarines videos carried out during recent oceanographic cruises revealed that submarine flat-top seamounts correspond to karstified and drowned shallow-water carbonate platforms largely covered by volcanic material and structured by a dense network of normal faults. Microfacies and well-constrained... |
| Tipo: Text |
Palavras-chave: Carbonate platform; Drowning; Volcanism; Tectonic; Mozambique Channel. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00384/49554/50048.pdf |
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| Dupré, Stephanie; Loubrieu, Benoit; Pierre, C.; Scalabrin, Carla; Guerin, Charline; Ehrhold, Axel; Ogor, Andre; Gautier, Emeric; Ruffine, Livio; Biville, Romain; Saout, Johan; Breton, C; Floodpage, J.; Lescanne, M.. |
| A few thousand (2612) seeps are releasing microbial methane bubbles from the seafloor at the Aquitaine Shelf edge (Bay of Biscay) at shallow water depths (140‐220 m). This methane contributes to the formation of meter‐scale subcircular carbonate structures, which are (sub‐)outcropping over 375 km2. Based on in situ flow rate measurements and acoustic data, and assuming steady and continuous fluxes over time, the methane entering the water column is estimated to 144 Mg/yr. Microbial methane circulation has been on‐going for at least a few thousand years. This discovery highlights the importance of microbial methane generation, disconnected from deep thermogenic sources and gas hydrates, at continental shelves. The shelf edge may be viewed as a focus area... |
| Tipo: Text |
Palavras-chave: Microbial methane; Continental shelf; Fluid emissions; High‐resolution acoustics; Aquitaine Margin; Methane‐derived authigenic carbonates. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00618/72982/72057.pdf |
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| Miramontes, Elda; Jouet, Gwenael; Thereau, Estelle; Bruno, Miguel; Penven, Pierrick; Guerin, Charline; Le Roy, Pascal; Droz, Laurence; Jorry, Stephan; Hernández‐molina, F. Javier; Thiéblemont, Antoine; Silva Jacinto, Ricardo; Cattaneo, Antonio. |
| Evidences of sedimentation affected by oceanic circulation, such as nepheloid layers and contourites are often observed along continental slopes. However, the oceanographic processes controlling sedimentation along continental margins remain poorly understood. Multibeam bathymetry and high‐resolution seismic reflection data revealed a contourite depositional system in the Mozambican upper continental slope composed of a contourite terrace (a surface with a gentle seaward slope dominated by erosion) and a plastered drift (a convex‐shape sedimentary deposit). A continuous alongslope channel and a field of sand dunes (mainly migrating upslope), formed during Holocene, were identified in the contourite terrace at the present seafloor. Seismic reflection data... |
| Tipo: Text |
Palavras-chave: Contourite; Sediment drift; Bedform; Sedimentary processes; Tide; Internal solitary waves; Bottom currents. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00605/71730/70205.pdf |
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| Miramontes Garcia, Elda; Jouet, Gwenael; Cattaneo, Antonio; Thereau, Estelle; Guerin, Charline; Jorry, Stephan; Droz, Laurence. |
| The upper slopes of continental margins are very energetic areas where nepheloid layers are often observed. Multibeam bathymetry, sub-bottom profiler and multi-channel highresolution seismic reflection data acquired during the PAMELA-MOZ04 survey in the Mozambique Channel revealed the presence of sand dunes on the upper slope at 120-250 m water depth. The dunes migrate upslope and their crests are oblique to the contours. They are medium to large dunes, with wavelengths between 20 and 150 m and heights between 0.15 and 1.50 m, and their size decreases upslope. Seismic reflection data of the water column show internal solitary waves travelling offshore in the depth range of the dune field. The formation of the dune field could be related to the interaction... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00499/61049/64460.pdf |
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| Registros recuperados: 12 | |
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