Consulta: subjectFacets:"Canyon"
Registros recuperados: 9
Data/hora: 11/06/2024 01:24:32

Demise of a submarine canyon? Evidence for highstand infilling on the Waipaoa River continental margin, New Zealand
Provedor de dados: 5
Autores: Walsh, J. P.; Alexander, C. R.; Gerber, T.; Orpin, A. R.; Sumners, B. W.
Submarine canyons are major geomorphologic features on the Earth's surface. Their formation has received considerable debate, but their demise has received less attention. Research of modern canyons with cores and moorings has documented active sediment transport and deposition, but extrapolation of these local observations over larger areas is precluded by complex canyon geomorphology. High-resolution multibeam and chirp data presented here provide convincing evidence of an infilling canyon head on the Waipaoa River margin of New Zealand. Tens of meters of Holocene sediment have accumulated on the outer shelf and in Lachlan canyon as a result of off-shelf sediment transport. Regardless of the ultimate fate of this system over geological time scales, this...
Tipo: Text
Palavras-chave: Canyon; Infilling; Waipaoa.
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00238/34924/33260.pdf

Ecologie et cartographie des coraux d’eau froide du canyon de Lacaze-Duthiers en Méditerranée; Données de la campagne CALADU 2019
Provedor de dados: 5
Autores: Sanchez, Pierre; Fabri, Marie-claire.
This work aimed to study populations of cold-water corals in the Lacaze-Duthiers canyon, a French canyon in the western part of the Gulf of Lion. the study was carried out using photos and videos of the wire-Remote Operated Vehicle: the HROV Ariane. Analysis of photos and videos allowed us to obtain information on the general biodiversity, on the spatial and vertical distribution and on the population density of the coldwater coral communities of the canyon but also on the size ranges and of colors of these species. Thus, it was noted that Madrepora oculata was the most represented species. This species has been observed in abundance ten times greater than the Lophelia pertusa species, which presented very dense distributions in places and then almost...
Tipo: Text
Palavras-chave: Canyon; Mer Méditerranée; Coraux d’eau froide; Cartographie d’habitats; Distribution spatiale; Madrepora oculata; Desmophyllum pertusum (Lophelia pertusa); Biodivesrsité.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00644/75634/76497.pdf

Activity and composition of the benthic fauna in the Whittard Canyon and the adjacent continental slope (NE Atlantic)
Provedor de dados: 5
Autores: Duineveld, Gérard; Lavaleye, Marc; Berghuis, Eilke; De Wilde, Peter.
We compared the sediment and its community on the Celtic continental slope (Goban Spur) with those in a branch of the nearby Whittard Canyon in search for evidence of canyon mediated transport of (labile) organic matter. We studied the megabenthos and macrobenthos biomass and taxonomic composition, measured in situ sediment community oxygen consumption and determined sediment concentrations of particulate organic carbon, phytopigments, and nucleic acids. While the sediment community and activity on the canyon fan was similar to that on the abyssal station near Goban Spur, the sediment within the canyon had relatively enhanced sediment community oxygen consumption rates and higher levels of phytopigments. particulate organic carbon and nucleic acids,...
Tipo: Text
Palavras-chave: Zone abyssale; Canyon; Macrofaune; Métabolisme; Pigments végétaux; Deep-sea; Canyon; Macrofauna; Metabolism; Phytopigments.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/00323/43370/42840.pdf

Major modification of sediment routing by a large Mass Transport Deposit in the Gulf of Lions (Western Mediterranean)
Provedor de dados: 5
Autores: Dennielou, Bernard; Jegou, I.; Droz, Laurence; Jouet, Gwenael; Cattaneo, Antonio; Berné, Serge; Aslanian, Daniel; Loubrieu, Benoit; Rabineau, Marina; Bermell, Sylvain.
In the Gulf of Lions (Western Mediterranean), the emplacement of a large (160 km3) Mass Transport Deposit, the Rhone Western Mass Transport Deposit (RWMTD), at the base of slope, aside the Rhone deep-sea fan between 1800 and 2700 m water depth, resulted in a major modification of the sediment routing by clogging a drainage network and blocking at the base of slope sediments that were previously routed into the Valencia channel and the Balearic abyssal plain. The RWMTD was sourced from sediments of the western flank of the Rhone upper fan and the adjacent base of slope. The mass transport deposit is characterized by a transparent seismic facies and sediment cores show that it is composed of a stiff laminated muddy lithofacies characteristic of the Rhone fan...
Tipo: Text
Palavras-chave: Gulf of Lions; Ebro margin; Sediment routing; Rhone deep-sea fan; Canyon; Mass transport deposit; Turbidite.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00480/59175/61813.pdf

Instabilities and deformation in the sedimentary cover on the upper slope of the southern Aquitaine continental margin, north of the Capbreton canyon (Bay of Biscay)
Provedor de dados: 5
Autores: Gonthier, E; Cirac, P; Faugeres, J; Gaudin, Mathieu; Cremer, M; Bourillet, Jean-francois.
Acoustic and core data have recently been collected on the shelf break and the upper part of the slope of the south Aquitaine continental margin. They reveal the major role played by mass-flow gravity processes in deposit erosion and redistribution, modelling of the sea-bed, and transfer of sediment toward the deep-sea. The study region is bounded in the south by the Capbreton canyon. The northern area, which shows a smooth morphology, is characterised by small-scale deformations due to sediment creep or low-amplitude slide processes. The deformations are associated with mini listric-like faults that bound packets of sediments in which the deposit geometry is typical of constructional sediment waves. These sediment waves result from the interaction of...
Tipo: Text
Palavras-chave: Sediment transfer; Mass flows; Sediment wave; Continental slope; Canyon; Bay of Biscay.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-3960.pdf

Seafloor litter from the continental shelf and canyons in French Mediterranean Water: Distribution, typologies and trends
Provedor de dados: 5
Autores: Gerigny, Olivia; Brun, Melanie; Fabri, Marie-claire; Tomasino, Corinne; Le Moigne, Morgan; Jadaud, Angelique; Galgani, Francois.
Seafloor litter has been studied both on the continental shelves (by trawling during 24 years) and in canyons (by ROV) of the French Mediterranean sea Water (FMW). On the continental shelf, mean densities range from 49.63 to 289.01 items/km2. The most abundant categories were plastic, glass/ceramics, metals and textiles. Trend analysis shows a significant increase in plastic quantities during the study period. Plastics accumulate at all depths, with heavier items being found in deeper areas, while the continental slope-break appears as a clean area. The spatial distribution of litter revealed the influence of geomorphologic factors, anthropic activities, shipping route, river inputs. All the canyons are affected by debris but coastal canyons (Ligurian Sea...
Tipo: Text
Palavras-chave: Marine litter; Seafloor; Canyon; Mediterranean Sea; Gulf of Lion; Corsica.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00507/61868/66074.pdf

Origin and Accumulation of Trace Elements in Sediments of the Northwestern Mediterranean Margin
Provedor de dados: 5
Autores: Cossa, Daniel; Buscail, R.; Puig, P.; Chiffoleau, Jean-francois; Radakovitch, Olivier; Jeanty, G.; Heussner, S.
Continental margins receive natural and anthropogenic trace elements (TEs) from direct atmospheric deposition of aerosols onto the sea surface and from advection of riverine suspended particles and/or resuspended sediments from the continental shelf/slope. When the margin is incised by submarine canyons, as for example in the Northwestern Mediterranean Sea, most of these particles are preferentially transferred via these topographic features towards their final repositories in the abyssal plain. The Gulf of Lions (GoL) shelf receives the largest particulate riverine input to the Western Mediterranean, with its associated chemical contaminants originating from the industrialized and urbanized Rhone Valley. Sediments samples (grabs, cores and moored traps)...
Tipo: Text
Palavras-chave: Trace-element; Sediment; Canyon; Continental margin; Mediterranean.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00188/29971/28424.pdf

Origin of an enigmatic regional Mio-Pliocene unconformity on the Demerara plateau
Provedor de dados: 5
Autores: Pattier, France; Loncke, L.; Imbert, Patrice; Gaullier, V.; Basile, C.; Maillard, Alexandre; Roest, Walter; Patriat, Martin; Vendeville, B. C.; Marsset, Tania; Bayon, Germain; Cathalot, Cecile; Caprais, Jean-claude; Bermell, Sylvain; Sotin, Christine; Hebert, Bertil; Mercier De Lepinay, Marion; Lebrun, J. F.; Marcaillou, B.; Heuret, A.; Droz, Laurence; Graindorge, David; Poetisi, E.; Berrenstein, H.
The Demerara plateau, located offshore French Guiana and Suriname, is part of a passive transform continental margin particularly prone to develop slope instabilities, probably in relation to the presence of a free distal border along its steep continental slope. Slope failure occurred at different periods (Cretaceous to Neogene) and shows an overall retrogressive evolution through time. Upslope these failure headscarp, an enigmatic regional MioPliocene unconformity has been discovered through the interpretation of new academic and industrial datasets. The aim of this work is to describe and understand the origin of this surface. Our analysis shows that this unconformity is made of a series of valleys that cross-cut sedimentary strata. Each one of these...
Tipo: Text
Palavras-chave: Unconformity; Hydrate pockmark; Slide; Contourite; Valley; Canyon; Demerara plateau.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00271/38193/36735.pdf

High and low frequency erosive and constructive cycles in estuarine beaches: an example from Garcez Point, Bahia/Brazil
Provedor de dados: 42
Autores: BITTENCOURT,ABÍLIO C.S.P.; LESSA,GUILHERME C.; DOMINGUEZ,JOSÉ M.L.; MARTIN,LOUIS; VILAS BÔAS,GERALDO S.; FARIAS,FÉLIX F.
Monitoring of the morphodynamic variations of the beaches associated with an estuary contiguous with Garcez Point, Bahia, Brazil, and the superposition of aerial photographs from the region, show the presence of distinctive erosive and constructive cycles of low and high frequencies. Between 1959 and 1989, one event of shoreline erosion and progradation was recognized on the oceanic beaches just outside the estuary. Inside the estuary, an erosion phase at the southern margin coincides with a constructive phase at the other side, and vice-versa. On the southern estuarine beach, low-frequency cycles of erosion and progradation are also perceived, but with the inverse trend when compared to the contiguous oceanic beach. During the beach monitoring period...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Erosive and constructive cycles; Longshore sand transport; Wave refraction; Canyon; Ebb-tidal delta; Bahia/Brazil.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652001000400013