|
|
|
| Registros recuperados: 17 | |
|
|
| Hermidas, Navid; Silva Jacinto, Ricardo; Eggenhuisen, Joris T.; Luthi, Stefan M.. |
| A new viscoelastic constitutive model for subaqueous clay-rich gravity flows is presented. It is explained that for the materials which exhibit a minimum in their strain controlled flow curves the structure parameter must be a symmetric function of strain rate and stress. Therefore, the destruction of structure within the material is modeled using the dissipation energy. An expression for the elastic strain of the flowing structure is derived. The final set of equations can reproduce the viscosity bifurcation that clay suspensions may exhibit under a given load. This is explained to be important for prediction of the run-out distance of clay-rich gravity flows. The ability of the model to reproduce the general response of pasty materials to step stress and... |
| Tipo: Text |
Palavras-chave: Gravity flow; Thixotropy; Clay suspension; Viscosity bifurcation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00483/59497/62365.pdf |
| |
|
|
| Duros, Pauline; Silva Jacinto, Ricardo; Dennielou, Bernard; Schmidt, S.; Martinez Lamas, Ruth; Gautier, Emeric; Roubi, Angelique; Gayet, Nicolas. |
| Living (Rose Bengal stained) and dead benthic foraminifera were investigated at 6 deep-sea sites sampled in the Capbreton canyon area (Bay of Biscay, France). Three sites were located along the canyon axis at 301 m, 983 m and 1478 m and 3 stations were positioned on adjacent terraces at 251 m, 894 m and 1454 m. Sedimentary features indicate that frequent sedimentary disturbances of different magnitudes occur along the Capbreton canyon axis and adjacent terraces. Such environmental conditions cause the presence of very particular benthic environments. Along the 6 studied sites, different foraminiferal responses to various sedimentary patterns are observed revealing the complexity of this canyon environment. Some sites (Gitan 3 (canyon axis), Gitan 5 (canyon... |
| Tipo: Text |
Palavras-chave: Benthic foraminifera; Capbreton canyon; Habitat disturbance; Turbidite; Submarine canyon. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00360/47121/47052.pdf |
| |
|
|
| Miramontes, Elda; Eggenhuisen, Joris T.; Silva Jacinto, Ricardo; Poneti, Giovanni; Pohl, Florian; Normandeau, Alexandre; Campbell, D. Calvin; Hernandez-molina, F. Javier. |
| Turbidity currents and contour currents are common sedimentary and oceanographic processes in deep-marine settings that affect continental margins worldwide. Their simultaneous interaction can form asymmetric and unidirectionally migrating channels, which can lead to opposite interpretations of paleocontour current direction: channels migrating against the contour current or in the direction of the contour current. In this study, we performed three-dimensional flume-tank experiments of the synchronous interaction between contour currents and turbidity currents to understand the effect of these combined currents on channel architecture and evolution. Our results show that contour currents with a velocity of 10-19 cm s(-1) can substantially deflect the... |
| Tipo: Text |
|
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00624/73602/73028.pdf |
| |
|
|
| Khripounoff, Alexis; Crassous, Philippe; Lo Bue, N.; Dennielou, Bernard; Silva Jacinto, Ricardo. |
| Current velocities and vertical sediment fluxes in the Var submarine canyon were assessed at three stations respectively at 800 m, 1200 m and 1800 m depth, using moorings deployed for 4 months during winter 2008-2009. During this period, we observed three major sediment gravity flows, all characterized by sudden increases in current velocity that lasted 2-5 h and by downward particle fluxes. Each gravity flow, described using a high frequency current meter and two Acoustic Doppler Current Profiler (75 and 300 kHz ADCP) showed distinctive features. The first event, triggered during a flood of the Var River, was determined to be a hyperpycnal current with a large vertical extent (>100 m high) and relatively low velocity (40 cm s(-1)). The second event,... |
| Tipo: Text |
|
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00113/22394/20343.pdf |
| |
|
|
| Hage, Sophie; Cartigny, Matthieu J.b.; Sumner, Esther J.; Clare, Michael A.; Hughes Clarke, John E.; Talling, Peter J.; Lintern, D. Gwyn; Simmons, Stephen M.; Silva Jacinto, Ricardo; Vellinga, Age J.; Allin, Joshua R.; Azpiroz‐zabala, Maria; Gales, Jenny A.; Hizzett, Jamie L.; Hunt, James E.; Mozzato, Alessandro; Parsons, Daniel R.; Pope, Ed L.; Stacey, Cooper D.; Symons, William O.; Vardy, Mark E.; Watts, Camilla. |
| Rivers (on land) and turbidity currents (in the ocean) are the most important sediment transport processes on Earth. Yet, how rivers generate turbidity currents as they enter the coastal ocean remains poorly understood. The current paradigm, based on laboratory experiments, is that turbidity currents are triggered when river plumes exceed a threshold sediment concentration of ~1 kg.m‐3. Here we present direct observations of an exceptionally dilute river‐plume, with sediment concentrations one order of magnitude below this threshold (0.07 kg.m‐3), which generated a fast (1.5 m.s‐1), erosive, short‐lived (6 min) turbidity current. However, no turbidity current occurred during subsequent river‐plumes. We infer that turbidity currents are generated when... |
| Tipo: Text |
|
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00514/62594/66952.pdf |
| |
|
|
| Alzieu, Claude; Abarnou, Alain; Bassoullet, Philippe; Boutier, Bernard; Chiffoleau, Jean-francois; Crenn, Isabelle; Derrien, Annick; Erard-le Denn, Evelyne; Gourmelon, Michele; Guiliaud, Jean-françois; Silva Jacinto, Ricardo; Le Cann, Pierre; Le Guyader, Françoise; Le Hir, Pierre; L'Yavanc, Jacky; Mauvais, Jean-louis; Menard, Dominique; Michel, Pierre; Monbet, Yves; Pommepuy, Monique; Quiniou, Francoise. |
| Port activities require continuous or occasional dredging of considerable quantities of sediments : approximately 50 million m3 along the French coastline. A large proportion of the dredgings is authorized for dumping at sea in geographically delimited areas and following an impact evaluation of their potential harmfulness to the marine environment. The environmental risks assessment linked to dredging operations relies on knowledge related to several scientific disciplines contributing to changes in the regulations. This work, intended both for managers and for environmental scientists and engineers, is designed to take stock of the current state-of-the-art in the field of sediment contamination and related ecotoxicological hazards, along with a review of... |
| Tipo: Text |
Palavras-chave: Regulations; Management; Impact; Contaminants; Dredging; Réglementation; Gestion; Impact; Contaminants; Dragages. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/1999/rapport-1040.pdf |
| |
|
|
| Bonneau, Lucile; Toucanne, Samuel; Bayon, Germain; Jorry, Stephan; Emmanuel, Laurent; Silva Jacinto, Ricardo. |
| In this study we used major element composition, neodymium isotopes ratios (εNdεNd) and concentration of REE to track and quantify the sediment routing in the Var sedimentary system from source (Southern French Alps) to sink (Ligurian Sea) over the last 50 ka. Our data reveal that changes in sediment sources over that period, associated with concomitant changes in the hyperpycnal (i.e. flood-generated turbidity currents) activity in the Var submarine canyon, were mainly driven by paleoenvironmental conditions in the upper basin and in particular by the presence of glaciers during the last glacial period. Based on this evidence, we determined when and how glacier-derived sediments were produced, then excavated and transferred to the ocean, allowing us to... |
| Tipo: Text |
Palavras-chave: Var; Routing system; Glacial erosion; Source-to-sink. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00358/46957/47130.pdf |
| |
|
|
| Clare, Michael; Lintern, D. Gwyn; Rosenberger, Kurt; Hughes Clarke, John E.; Paull, Charles; Gwiazda, Roberto; Cartigny, Matthieu J. B.; Talling, Peter J.; Perara, Daniel; Xu, Jingping; Parsons, Daniel; Silva Jacinto, Ricardo; Apprioual, Ronan. |
| Turbidity currents transport globally significant volumes of sediment and organic carbon into the deep-sea and pose a hazard to critical infrastructure. Despite advances in technology, their powerful nature often damages expensive instruments placed in their path. These challenges mean that turbidity currents have only been measured in a few locations worldwide, in relatively shallow water depths (,,2 km). Here, we share lessons from recent field deployments about how to design the platforms on which instruments are deployed. First, we show how monitoring platforms have been affected by turbidity currents including instability, displacement, tumbling and damage. Second, we relate these issues to specifics of the platform design, such as exposure of large... |
| Tipo: Text |
|
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00640/75200/75333.pdf |
| |
|
|
| Bonneau, Lucile; Jorry, Stephan J.; Toucanne, Samuel; Silva Jacinto, Ricardo; Emmanuel, Laurent. |
| Although it is widely accepted that erosion and sediment transfer respond to millennial-scale climatic variability, these changes remain difficult to detect in marine sedimentary archives. In the Var sediment-routing system, northwestern Mediterranean Sea, the absence of a continental shelf results in a direct connection between the Var River mouth and the deep basin during both highstand and lowstand conditions. This makes the Var sediment-routing system an ideal target to test whether rivers can transmit climate-driven high-frequency changes in sediment flux to the ocean. On the basis of an unprecedented (centennial-to-millennial-scale) resolution in turbidite sequences, we reconstructed the activity of turbidity current overflows along the deep-sea Var... |
| Tipo: Text |
|
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00248/35925/34447.pdf |
| |
|
|
| Payo-payo, Marta; Silva Jacinto, Ricardo; Lastras, G.; Rabineau, Marina; Puig, P.; Martin, J.; Canals, M.; Sultan, Nabil. |
| Bottom trawling leads to recurrent sediment resuspension events over fishing grounds. Recent studies have shown how bottom trawling can drive seascape reshaping at large spatial scales and enhance sediment transport in submarine canyons, which subsequently impacts deep-sea ecosystems. Present knowledge on the transfer and accumulation of sediment flows triggered by bottom trawling is based on localized and infrequent measurements whilst a more complete picture of the process is needed. The present work focuses on the modeling of sediment transport and accumulation resulting from trawling activities in La Fonera submarine canyon, northwestern Mediterranean Sea, thus contributing to an improved assessment of trawling impacts. Based on mooring data within a... |
| Tipo: Text |
Palavras-chave: Bottom trawling; Inverse model; Modeling; Sediment transport; Submarine canyon; Turbidity currents. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00374/48549/48862.pdf |
| |
|
|
| Minto'O, Charlie Morelle Angue; Silva Jacinto, Ricardo; Bassetti, Maria-angela; Jouet, Gwenael. |
| In this study, the model H(i) = 109.6103 + C1 × F1(i) + C2 × F2(i) + … + C33 × F33(i) obtained from depth modelling based on 33 recent benthic foraminifer species distribution, has been applied to the fossil benthic foraminifers from the borehole GDEC-4-2 drilled at a water depth of 491 m, in the East-Corsica basin, covering the last 550,000 years. The obtained variations of the paleo-depths show a medium correlation with the oscillations of the relative sea level and also with the fluctuations of the oxygen isotopic ratio (δ18O G. bulloides and δ18O C. pachyderma–C. wuellerstorfi). This newly developed transfer function is accompanied by an error margin of ± 86 m, suggesting that this model will probably be more suitable for a time scale of the order of a... |
| Tipo: Text |
Palavras-chave: Benthic foraminifers; East-Corsica basin; Paleo-depths; Transfer function. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00463/57477/64237.pdf |
| |
|
|
| Alzieu, Claude; Andral, Bruno; Bassoullet, Philippe; Boutier, Bernard; Gonzalez, Jean-louis; Huet, Martial; Jestin, Herve; L'Yavanc, Jacky; Michel, Pierre; Paulet, Yves-marie; Quiniou, Francoise; Silva Jacinto, Ricardo. |
| Le projet à pour but de modéliser la dispersion des immersions des boues de dragage, à partir de modèles numériques de manière à pouvoir évaluer le devenir de la charge particulaire et des contaminants associés. Les résultats des expérimentations en laboratoire montrent, qu'à l'échelle représentative du temps de séjour des particules dans la colonne d'eau du champ proche (quelques heures), on ne constate pas de solubilisation des métaux. La libération de la fraction associée aux eaux interstitielles et les flux à l'interface eau-sédiment (diagenèse précoce) après dépôt des sédiments rejetés, sont les processus qui pourraient être la cause d'un apport important de Cd (ou autre contaminant) dissous dans le milieu. Les hypothèses retenues pour l'élaboration... |
| Tipo: Text |
|
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00075/18621/16172.pdf |
| |
|
|
| 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 |
| |
|
|
| Miramontes, Elda; Penven, Pierrick; Fierens, Ruth; Droz, Laurence; Toucanne, Samuel; Jorry, Stephan; Jouet, Gwenael; Pastor, Lucie; Silva Jacinto, Ricardo; Gaillot, Arnaud; Giraudeau, Jacques; Raisson, François. |
| Mixed turbidite-contourite systems can be found in oceans where bottom currents and turbidity currents interact. The Zambezi turbidite system, located in the Mozambique Channel (SW Indian Ocean), is one of the largest sedimentary systems in the world in length and area of the related catchments. The oceanic circulation in the Mozambique Channel is intense and complex, dominated by eddies flowing southwards and deep currents flowing northwards along the Mozambican margin. Current measurements obtained from moorings at 3400–4050 m water depth in the Zambezi and Tsiribihina valleys show periods of intense currents at the seafloor with peaks of 40–50 cm s−1 that last up to one month and are not related to turbidity currents. These strong bottom-current events... |
| Tipo: Text |
Palavras-chave: Contourite; Turbidity current; Mixed system; Oceanic circulation; Mooring; ADCP; ROMS model; Bedform. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00476/58743/61269.pdf |
| |
|
| |
|
|
| Guiastrennec-faugas, Léa; Gillet, Hervé; Silva Jacinto, Ricardo; Dennielou, Bernard; Hanquiez, Vincent; Schmidt, Sabine; Simplet, Laure; Rousset, Antoine. |
| The Capbreton submarine canyon is a striking feature of the south-east of the Bay of Biscay. This canyon forms a deep incision through the continental shelf and slope, and displays remarkable structures linked to its present-day hydrosedimentary activity. Its head has been disconnected from the Adour River since 1310 CE, but remains close enough to the coast to be supplied with sediment by longshore drift. Gravity processes in the canyon body are abundantly described and documented, but activity in the head and the fan of the canyon is poorly constrained. Furthermore, many questions remain regarding the details of processes affecting the head, the body and the fan of the Capbreton canyon. In this work, we address the paucity of documentation concerning (1)... |
| Tipo: Text |
Palavras-chave: Submarine canyon; Bathymetric time-lapse; Morphobathymetry; Knickpoints. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00606/71834/70355.pdf |
| |
|
|
| Palm, Franziska A.; Peakall, Jeff; Hodgson, David M.; Marsset, Tania; Silva Jacinto, Ricardo; Dennielou, Bernard; Babonneau, Nathalie; Wright, Tim J.. |
| Submarine-fan channels can build the largest sediment accumulations on Earth, but our understanding of flow and sedimentation processes related to channel evolution remains limited. Results from physical and numerical modelling predict dominantly downstream channel bend migration. However, observations and evolutionary models for aggradational submarine channels on passive margins suggest that bends are dominated by lateral expansion. This paradox may be due to limitations induced by the use of constant width channels in process studies. Constant width has been used for two reasons: partly because this is the simplest possible case, but primarily because the width variation around submarine channel bends is unknown. Channel width variations are examined... |
| Tipo: Text |
Palavras-chave: Submarine channel; Congo; Channel morphology; Sedimentation; Bank pull; Quaternary; Monsoon; South Atlantic. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00693/80473/83602.pdf |
| |
| Registros recuperados: 17 | |
|
|
|
