Consulta: subjectFacets:"Sedimentary processes"
Registros recuperados: 6
Data/hora: 01/06/2024 09:58:26

The impact of internal waves on upper continental slopes: insights from the Mozambican margin (SW Indian Ocean)
Provedor de dados: 5
Autores: 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

Contourite depositional systems along the Mozambique channel: The interplay between bottom currents and sedimentary processes
Provedor de dados: 5
Autores: 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

High resolution seafloor images in the Gulf of Cadiz, Iberian margin
Provedor de dados: 5
Autores: Hanquiez, V; Mulder, T; Lecroart, P; Gonthier, E; Marches, E; Voisset, Michel.
In the Gulf of Cadiz, the hydrodynamic process acting on particle transport and deposition is a strong density-driven bottom current caused by the outflow of the saline deep Mediterranean water at the Strait of Gibraltar: the Mediterranean Outflow Water (MOW). New high resolution acoustic data including EM300 multibeam echo-sounder, deep-towed acoustic system SAR and very high resolution seismic, completed by piston cores collected during the CADISAR cruise allow to improve the understanding of the hydrodynamics of the MOW in the eastern part of the Gulf of Cadiz. Interpretation of data corrects the previous model established in this area and allows, for the first time, the accurate characterization of various bedforms and erosive structures along the MOW...
Tipo: Text
Palavras-chave: Instabilities; Sedimentary processes; Acoustic facies; Deep towed SAR; Contourites; Mediterranean Outflow Water MOW; Gulf of Cadiz.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3676.pdf

Searching for the seafloor signature of the 21 May 2003 Boumerdès earthquake offshore central Algeria
Provedor de dados: 5
Autores: Cattaneo, Antonio; Babonneau, Nathalie; Ratzov, G.; Dan-unterseh, G.; Yelles, K.; Bracene, R.; De Lepinay, B. Mercier; Boudiaf, A.; Deverchere, Jacques.
Shaking by moderate to large earthquakes in the Mediterranean Sea has proved in the past to potentially trigger catastrophic sediment collapse and flow. On 21 May 2003, a magnitude 6.8 earthquake located near BoumerdSs (central Algerian coast) triggered large turbidity currents responsible for 29 submarine cable breaks at the foot of the continental slope over similar to similar to 150 km from west to east. Seafloor bathymetry and backscatter imagery show the potential imprints of the 2003 event and of previous events. Large slope scarps resulting from active deformation may locally enhance sediment instabilities, although faults are not directly visible at the seafloor. Erosion is evident at the foot of the margin and along the paths of the numerous...
Tipo: Text
Palavras-chave: Western mediterranean sea; Cascadia subduction zone; Turbidity current; Zemmouri earthquake; Sedimentary processes; Submarine landslides; Northern algeria; Margin; Gps; Boundary.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00098/20959/18571.pdf

Origin of shallow submarine mass movements and their glide planes-Sedimentological and geotechnical analyses from the continental slope off northern Norway
Provedor de dados: 5
Autores: Baeten, Nicole J.; Laberg, Jan Sverre; Vanneste, Maarten; Forsberg, Carl Fredrik; Kvalstad, Tore J.; Forwick, Matthias; Vorren, Tore O.; Haflidason, Haflidi.
Submarine landslides are often characterized by a basal surface of rupture parallel to the stratigraphy, in which downslope movement is initiated. However, little is known about the sedimentology and physical properties of the sediments within these surfaces. In this study, we present a multiproxy analysis of the sediments collected from a giant piston core penetrating a shallow submarine mass transport deposit, in combination with high-resolution seismoacoustic data to identify and characterize the basal glide plane and the weaker sediments in which movement was initiated. The initial phase of instability consists of a single fracture that formed due to the downslope movement of a mostly intact slab of sediments. The 16m long core, comprising mostly...
Tipo: Text
Palavras-chave: Mass movement; Glide plane; Sedimentary processes; Geotechnical analysis; Seafloor stability; Hazard potential.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00289/40053/39368.pdf

Organic Carbon Origin, Benthic Faunal Consumption, and Burial in Sediments of Northern Atlantic and Arctic Fjords (60–81°N)
Provedor de dados: 5
Autores: Włodarska‐kowalczuk, Maria; Mazurkiewicz, Mikołaj; Górska, Barbara; Michel, Loic; Jankowska, Emilia; Zaborska, Agata.
Fjords have been recently recognized as hotspots of organic carbon (Corg) sequestration in marine sediments. This study aims to identify regional and local drivers of variability of Corg burial in north Atlantic and Arctic fjords. We provide a comparative quantification of Corg, δ13C, photosynthetic pigments content, benthic biomass, consumption, Corg accumulation and burial rates in sediments in six fjords (60 to 810N). Higher sediment Corg content in southern Norway reflected longer phytoplankton growth season and higher productivity. Higher contributions of terrestrial Corg were noted in temperate/southern Norway (dense land vegetation and high precipitation) and Arctic/Svalbard (glacial erosion) than in subarctic/northern Norway locations. Benthic...
Tipo: Text
Palavras-chave: S; Organic matter preservation; Organic carbon sequestration; Benthic carbon mineralization; Sedimentary processes; Early diagenesis; Marine geochemistry.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00591/70318/68353.pdf