Consulta: creatorFacets:"Canals, M"
Registros recuperados: 9
Data/hora: 03/06/2024 10:59:39

Triggering mechanisms of slope instability processes and sediment failures on continental margins: a geotechnical approach
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Sultan, Nabil; Cochonat, Pierre; Canals, M; Cattaneo, Antonio; Dennielou, Bernard; Haflidason, H; Laberg, J; Long, D; Mienert, J; Trincardi, F; Urgeles, R; Vorren, T; Wilson, C.
The Costa target areas exhibit the variability of slope instabilities needed to improve our understanding of sediment physical and mechanical properties in areas prone to sliding. That is why in this project, we have analysed the different slope failures events from different parts of the Costa target areas, which reflect diverse triggering mechanisms. The aim of the first part of this study was to identify the geotechnical response of the sediment to different external mechanisms (earthquake, rapid sedimentation and gas hydrate melting). We have focused on the relation between external mechanisms and the consequence change in the in-situ stress state and the physical, mechanical, and elastic properties of the sediment. In the second part of the paper, the...
Tipo: Text
Palavras-chave: Slope instability; Sensitivity; Sedimentation; Hydrate; Earthquake.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/publication-700.pdf

Variability of the western Mediterranean Sea surface temperature during the last 25,000 years and its connection with the Northern Hemisphere climatic changes
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Cacho, I; Grimalt, Jo; Canals, M; Sbaffi, L; Shackleton, Nj; Schonfeld, J; Zahn, R.
Sea surface temperature (SST) profiles over the last 25 kyr derived from alkenone measurements are studied in four cores from a W-E latitudinal transect encompassing the Gulf of Cadiz (Atlantic Ocean), the Alboran Sea, and the southern Tyrrhenian Sea (western Mediterranean). The results document the sensitivity of the Mediterranean region to the short climatic changes of the North Atlantic Ocean, particularly those involving the latitudinal position of the polar front. The amplitude of the SST oscillations increases toward the Tyrrhenian Sea, indicating an amplification effect of the Atlantic signal by the climatic regime of the Mediterranean region. All studied cores show a shelter cooling phase (700 years) for the Younger Dryas (YD) than that observed in...
Tipo: Text
Ano: 2001
URL: https://archimer.ifremer.fr/doc/00220/33173/31682.pdf

Eivissa slides, western Mediterranean Sea: morphology and processes
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lastras, Galderic; Canals, M; Amblas, D; Ivanov, M; Dennielou, Bernard; Droz, Laurence; Akhmetzhanov, A.
After obtaining full-coverage swath bathymetry data in 1995 and very high-resolution acoustic profiles in 2002, four slides at the Balearic Margin of the Eivissa Channel in the western Mediterranean Sea were revisited in 2004 when side-scan sonar data were collected using a MAK-1M deep-towed acoustic system. These new findings, higher in resolution than those for the swath bathymetry, show two main features previously undetected within these submarine landslides: (1) a series of step-forming inclined and detached slabs oriented perpendicular to the slide movement and located in the uppermost part of the slides, and (2) arcuate regular positive ridges oriented also normal to the slide movement and located in the depositional lobes of some of the slides. The...
Tipo: Text
Palavras-chave: Morphology; Bathymetry; Slides; Mediterranean sea; Eivissa channel.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-2087.pdf

Impact of iceberg melting on Mediterranean thermohaline circulation during Heinrich events
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Sierro, Fj; Hodell, Da; Curtis, Jh; Flores, Ja; Reguera, I; Colmenero-hidalgo, E; Barcena, Ma; Grimalt, Jo; Cacho, I; Frigola, J; Canals, M.
Down-core samples of planktonic and benthic foraminifera were analyzed for oxygen and carbon isotopes in International Marine Past Global Changes Study (IMAGES) core MD99-2343 in order to study the interactions between climate change in the Northern Hemisphere and the western Mediterranean thermohaline circulation at times of Heinrich events (HE). Our results confirm the antiphase correlation between enhanced North Atlantic Deep Water formation and low ventilation in the Mediterranean. However, this study reveals that this antiphase relationship in deepwater formation between the North Atlantic and Mediterranean was interrupted during times of HE when the injection of large volumes of water from melting icebergs reached the entrance to the Mediterranean....
Tipo: Text
Palavras-chave: Climatic change; Heinrich events; Mediterranean Sea; Carbon and oxygen isotopes; Thermohaline circulation; Pleistocene.
Ano: 2005
URL: https://archimer.ifremer.fr/doc/00232/34354/32759.pdf

Axial incision: The key to understand submarine canyon evolution (in the western Gulf of Lion)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Baztan, Juan; Berne, Serge; Olivet, Jean-louis; Rabineau, Marina; Aslanian, Daniel; Gaudin, Mathieu; Rehault, Jean Pierre; Canals, M.
A detailed morphological analysis of the outer shelf and continental slope of the Western Gulf of Lion is presented, based on swath bathymetry data together with sub-bottom profiles and high resolution seismic reflection profiles. These data reveal two main erosive features, of very different dimensions: the axial incision and the canyon's major valley. The height of axial incisions' flanks with respect to the canyon deepest point (the thalweg) ranges from 40 to 150 m. It creates a small axial erosive path within the canyon's major valley, which is typically bounded by flanks of more than 700 m in height. We interpret the axial incision observed in the sea floor as the imprint of turbidity currents that eroded the floor of canyons during phases of...
Tipo: Text
Palavras-chave: Submarine canyon; Axial incision; Gulf of Lion.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-353.pdf

A walk down the Cap de Creus canyon, Northwestern Mediterranean Sea: Recent processes inferred from morphology and sediment bedforms
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lastras, G; Canals, M; Urgeles, R; Amblas, D; Ivanov, M; Droz, Laurence; Dennielou, Bernard; Fabres, J; Schoolmeester, T; Akhmetzhanov, A; Orange, D; Garcia Garcia, A.
The Cap de Creus canyon, northwestern Mediterranean Sea, belongs to a complex network of submarine canyons cutting the western Gulf of Lion continental shelf and opening into the larger Sete canyon. Swath bathymetry data, MAKAM deep-towed side-scan sonar imagery and 5 kHz high resolution seismic reflection profiles show striking morphologies in the Cap de Creus canyon floor and walls. As a consequence of the canyon head and the upper reach severe incision, the continental shelf dramatically narrows in front of the Creus Cape promontory. The upper canyon has a flat-bottomed thalweg incised in a megascale sediment furrow field displaying hyperbolic seismic facies. The tens of kilometres long linear furrows extend also over the middle canyon down to 1400 in...
Tipo: Text
Palavras-chave: Gulf of Lion; Bedform; Swath bathymetry; Side scan sonar; Submarine canyon.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3602.pdf

Microbial activity at the deep water sediment boundary layer in two highly productive systems in the Western Mediterranean: the Almeria-Oran front and the Malaga upwelling
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Bianchi, A; Calafat, A; De Wit, R; Garcin, J; Tholosan, O; Cacho, I; Canals, M; Fabres, J; Grout, H; Masque, P; Sanchez-cabeza, Ja; Sempere, R.
Microbiological and biogeochemical studies were carried out in sediments and near bottom waters in the upwelling area off the Malaga coast and in the Almeria-Oran frontal zone. In these nutrient-rich conditions, metabolic activity is potentially limited by oxygen availability through the sediment depth. In the surficial sediments of the frontal zone, however, oxygen penetrated to a depth of 4 cm, allowing oxic mineralisation processes to occur throughout the layer. In the surficial sediments of the upwelling area, oxygen penetration was limited to the top 2.5 cm, leading to anoxic conditions. Glutamate respiration and global oxygen uptake rates were clearly higher than in the frontal zone. In the superficial sediments of the frontal zone, bacteria were...
Tipo: Text
Palavras-chave: Taux de minéralisation; Sédiments; Eaux profondes; Méditerranée occidentale; Bacteria; Mineralisation rate; Sediments; Deep-sea; Western Mediterranean.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/00322/43298/43034.pdf

A geomechanical approach for the genesis of sediment undulations on the Adriatic shelf - art. no. Q04R03
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Sultan, Nabil; Cattaneo, Antonio; Urgeles, R; Lee, H; Locat, J; Trincardi, F; Berne, Serge; Canals, M; Lafuerza, S.
This study is among the first to examine the genesis of the seafloor and subsurface undulations on the Adriatic continental shelf by integrating stratigraphic information and in situ and laboratory geotechnical measurements. Interpretation of sediment behavior is based on a 32-m-long borehole crossing ( 1) a possible shear plane and ( 2) a silty clay layer at about 20 m below seafloor (mbsf) on which sediment undulations are rooted and could be interpreted as a potential weak layer succession. Our main results in terms of triggering mechanism for the observed undulations show that under an earthquake, liquefaction and/or failure of the silty-clay sediments ( weak layer) leading to deformation of the upper more cohesive sediments is possible only when such...
Tipo: Text
Palavras-chave: Sediment deformation; Shear strength; Earthquake; Adriatic shelf.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4105.pdf

Shallow rocky bottom benthic assemblages as calcium carbonate producers in the Alboran Sea (southwestern Mediterranean)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Cebrian, E; Ballesteros, E; Canals, M.
Zonation patterns and species composition of the different assemblages encountered along the bathymetric axis are considered in order to quantify the biomass and calcium carbonate content of communities thriving in rocky bottoms of La Herradura (southwestern Mediterranean) between 0 and 50 m depth. Algal biomass is lower but total biomass is slightly higher to values recorded in other Mediterranean areas due to the high biomass of suspension feeders. Since most of the animals and algae with high biomass have calcareous skeletons, the calcimass is rather high (1 100 to 2400 g . CaCO3.m(-2)) when compared to other temperate and Mediterranean sites. A tentative estimate of yearly carbonate production yields 1 000 g . CaCO3.m(-2).y(-1) for the rocky bottoms of...
Tipo: Text
Palavras-chave: Carbonate; Fonds rocheux; Communautés benthiques; Production; Mer Méditerranée; Calcium carbonate; Rocky bottoms; Benthic assemblages; Production; Mediterranean Sea.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/00324/43565/44062.pdf