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Yingci Feng - One of the best experts on this subject based on the ideXlab platform.

  • The role of sediment gravity flows on the morphological development of a large submarine canyon (Taiwan Canyon), north‐east South China Sea
    Sedimentology, 2021
    Co-Authors: Tiago Marcos Alves, Michele Rebesco, Yingci Feng
    Abstract:

    High‐resolution multibeam bathymetric and multichannel seismic data are used to investigate the morphology of a submarine canyon (Taiwan Canyon), and its surrounding strata, in the north‐east South China Sea. This submarine canyon shows two main branches at its head, and changes its orientation from north‐west/south‐east to east–west due to the effect of a tectonically active seamount. The asymmetry of the submarine canyon’s banks in its middle reach is due to the combined action of recurrent slope instability and turbidity currents. In addition, two fields of sediment waves were identified in the study area. Field 1 is located on the south‐west levee of the canyon and is fed by turbidity currents from one of its branches, being also associated with marked hydraulic jumps. Field 2 is observed in the southern bank of the lower canyon reach and was formed by the overspill of turbidity currents within the Taiwan Canyon due to the effect of inertial centrifugal forces. Turbidity currents sourced from Dongsha Channel also contributed to forming Field 2. Importantly, trains of plunge pools have been identified along the thalweg of the lower canyon reach, generated by turbidity currents deriving from the submarine Canyons in the north of the Taiwan Canyon. These results not only provide a very detailed account of submarine bedforms within and around a large submarine canyon, but also contribute to a better understanding of their origin and development. The high‐resolution bathymetric and seismic data in this work reveal how gravity flows can drive erosion and deposition in submarine Canyons.

  • the role of sediment gravity flows on the morphological development of a large submarine canyon taiwan canyon north east south china sea
    Sedimentology, 2021
    Co-Authors: Tiago Marcos Alves, Michele Rebesco, Yingci Feng
    Abstract:

    High‐resolution multibeam bathymetric and multichannel seismic data are used to investigate the morphology of a submarine canyon (Taiwan Canyon), and its surrounding strata, in the north‐east South China Sea. This submarine canyon shows two main branches at its head, and changes its orientation from north‐west/south‐east to east–west due to the effect of a tectonically active seamount. The asymmetry of the submarine canyon’s banks in its middle reach is due to the combined action of recurrent slope instability and turbidity currents. In addition, two fields of sediment waves were identified in the study area. Field 1 is located on the south‐west levee of the canyon and is fed by turbidity currents from one of its branches, being also associated with marked hydraulic jumps. Field 2 is observed in the southern bank of the lower canyon reach and was formed by the overspill of turbidity currents within the Taiwan Canyon due to the effect of inertial centrifugal forces. Turbidity currents sourced from Dongsha Channel also contributed to forming Field 2. Importantly, trains of plunge pools have been identified along the thalweg of the lower canyon reach, generated by turbidity currents deriving from the submarine Canyons in the north of the Taiwan Canyon. These results not only provide a very detailed account of submarine bedforms within and around a large submarine canyon, but also contribute to a better understanding of their origin and development. The high‐resolution bathymetric and seismic data in this work reveal how gravity flows can drive erosion and deposition in submarine Canyons.

Tiago Marcos Alves - One of the best experts on this subject based on the ideXlab platform.

  • The role of sediment gravity flows on the morphological development of a large submarine canyon (Taiwan Canyon), north‐east South China Sea
    Sedimentology, 2021
    Co-Authors: Tiago Marcos Alves, Michele Rebesco, Yingci Feng
    Abstract:

    High‐resolution multibeam bathymetric and multichannel seismic data are used to investigate the morphology of a submarine canyon (Taiwan Canyon), and its surrounding strata, in the north‐east South China Sea. This submarine canyon shows two main branches at its head, and changes its orientation from north‐west/south‐east to east–west due to the effect of a tectonically active seamount. The asymmetry of the submarine canyon’s banks in its middle reach is due to the combined action of recurrent slope instability and turbidity currents. In addition, two fields of sediment waves were identified in the study area. Field 1 is located on the south‐west levee of the canyon and is fed by turbidity currents from one of its branches, being also associated with marked hydraulic jumps. Field 2 is observed in the southern bank of the lower canyon reach and was formed by the overspill of turbidity currents within the Taiwan Canyon due to the effect of inertial centrifugal forces. Turbidity currents sourced from Dongsha Channel also contributed to forming Field 2. Importantly, trains of plunge pools have been identified along the thalweg of the lower canyon reach, generated by turbidity currents deriving from the submarine Canyons in the north of the Taiwan Canyon. These results not only provide a very detailed account of submarine bedforms within and around a large submarine canyon, but also contribute to a better understanding of their origin and development. The high‐resolution bathymetric and seismic data in this work reveal how gravity flows can drive erosion and deposition in submarine Canyons.

  • the role of sediment gravity flows on the morphological development of a large submarine canyon taiwan canyon north east south china sea
    Sedimentology, 2021
    Co-Authors: Tiago Marcos Alves, Michele Rebesco, Yingci Feng
    Abstract:

    High‐resolution multibeam bathymetric and multichannel seismic data are used to investigate the morphology of a submarine canyon (Taiwan Canyon), and its surrounding strata, in the north‐east South China Sea. This submarine canyon shows two main branches at its head, and changes its orientation from north‐west/south‐east to east–west due to the effect of a tectonically active seamount. The asymmetry of the submarine canyon’s banks in its middle reach is due to the combined action of recurrent slope instability and turbidity currents. In addition, two fields of sediment waves were identified in the study area. Field 1 is located on the south‐west levee of the canyon and is fed by turbidity currents from one of its branches, being also associated with marked hydraulic jumps. Field 2 is observed in the southern bank of the lower canyon reach and was formed by the overspill of turbidity currents within the Taiwan Canyon due to the effect of inertial centrifugal forces. Turbidity currents sourced from Dongsha Channel also contributed to forming Field 2. Importantly, trains of plunge pools have been identified along the thalweg of the lower canyon reach, generated by turbidity currents deriving from the submarine Canyons in the north of the Taiwan Canyon. These results not only provide a very detailed account of submarine bedforms within and around a large submarine canyon, but also contribute to a better understanding of their origin and development. The high‐resolution bathymetric and seismic data in this work reveal how gravity flows can drive erosion and deposition in submarine Canyons.

Albert Palanques - One of the best experts on this subject based on the ideXlab platform.

  • Bottom-trawling along submarine Canyons impacts deep sedimentary regimes.
    Scientific Reports, 2017
    Co-Authors: Sarah Paradis, Jacobo Martín, Pere Puig, Pere Masqué, Xènia Juan-díaz, Albert Palanques
    Abstract:

    Many studies highlight that fish trawling activities cause seafloor erosion, but the assessment of the remobilization of surface sediments and its relocation is still not well documented. These impacts were examined along the flanks and axes of three headless submarine Canyons incised on the Barcelona continental margin, where trawling fleets have been operating for decades. Trawled grounds along canyon flanks presented eroded and highly reworked surface sediments resulting from the passage of heavy trawling gear. Sedimentation rates on the upper canyon axes tripled and quadrupled its natural (i.e. pre-industrialization) values after a substantial increase in total horsepower of the operating trawling fleets between 1960 s and 1970 s. These impacts affected the upper canyon reaches next to fishing grounds, where sediment resuspended by trawling can be transported towards the canyon axes. This study highlights that bottom trawling has the capacity to alter natural sedimentary environments by promoting sediment-starved canyon flanks, and by enhancing sedimentation rates along the contiguous axes, independently of Canyons’ morphology. Considering the global mechanisation and offshore expansion of bottom trawling fisheries since the mid-20th century, these sedimentary alterations may occur in many trawled Canyons worldwide, with further ecological impacts on the trophic status of these non-resilient benthic communities.

  • contemporary sediment transport processes in submarine Canyons
    Annual Review of Marine Science, 2014
    Co-Authors: Pere Puig, Albert Palanques, Jacobo Martín
    Abstract:

    Submarine Canyons are morphological incisions into continental margins that act as major conduits of sediment from shallow- to deep-sea regions. However, the exact mechanisms involved in sediment transfer within submarine Canyons are still a subject of investigation. Several studies have provided direct information about contemporary sedimentary processes in submarine Canyons that suggests different modes of transport and various triggering mechanisms. Storm-induced turbidity currents and enhanced off-shelf advection, hyperpycnal flows and failures of recently deposited fluvial sediments, dense shelf-water cascading, canyon-flank failures, and trawling-induced resuspension largely dominate present-day sediment transfer through Canyons. Additionally, internal waves periodically resuspend ephemeral deposits within Canyons and contribute to dispersing particles or retaining and accumulating them in specific regions. These transport processes commonly deposit sediments in the upper- and middle-canyon reaches ...

  • Sediment-Transport Processes in Submarine Canyons
    2014
    Co-Authors: Pere Puig, Albert Palanques, Jacobo Mart
    Abstract:

    Submarine Canyons are morphological incisions into continental margins that act as major conduits of sediment from shallow- to deep-sea regions. However, the exact mechanisms involved in sediment transfer within submarine Canyons are still a subject of investigation. Several studies have provided direct information about contemporary sedimentary processes in submarine Canyons that suggests different modes of transport and various triggering mechanisms. Storm-induced turbidity currents and enhanced off-shelf advection, hyperpycnal flows and failures of recently deposited fluvial sediments, dense shelf-water cascading, canyon-flank failures, and trawling-induced resuspension largely dominate present-day sediment transfer through Canyons. Additionally, internal waves periodically resuspend ephemeral deposits within Canyons and contribute to dispersing particles or retaining and accumulating them in specific regions. These transport processes commonly deposit sediments in the upper- and middle-canyon reaches for decades or centuries before being completely or partially flushed farther down-canyon by large sediment failures.

  • Suspended sediment fluxes and transport processes in the Gulf of Lions submarine Canyons. The role of storms and dense water cascading
    Marine Geology, 2006
    Co-Authors: Albert Palanques, Pere Puig, Miquel Canals, Antoni Calafat, Xavier Durrieu De Madron, Serge Heussner, Joan Fabres, Jorge Guillén, Jérôme Bonnin
    Abstract:

    Contemporary suspended sediment transport was studied in seven submarine Canyons of the Gulf of Lions (GoL). Current meters equipped with turbidity sensors were moored 4 m above bottom at 300 m depth in the canyon axis from November 2003 to May 2004. Sediment transport events were monitored and studied in relation to forcing conditions. There was a large flood in early December, during which discharges from all of the coastal rivers increased by more than one order of magnitude. A smaller flood of the Rhone River occurred later in mid-January followed by a persistent high river discharge that lasted until mid-February. There were also several E–SE storm events during the measurement period, two of them causing large swell, one in early December (max Hs: 8.4 m), coinciding with the major river flood,andoneinlateFebruary(maxHs:7m)duringaperiodoflowerriverdischarge.Mostofthevariabilityindown-canyoncurrentspeeds waslinkedtostrongdownwellinginducedbyE–SEstormsandtocascadingofdenseshelfwaterinducedbyNandNWwinds.Theintensity and timing of these processes strongly varied spatially. Eastern storms generated higher waves and induced stronger downwelling in the western than in the eastern sector of the GoL. Shelf dense water cascading events were enhanced during eastern storms and they were also more intense in the western sector of the GoL. These events occurred frequently from January to May along the western Canyons and from February to April along the eastern Canyons. From February to April they occurred simultaneously in all the Canyons. Sediment transport was mainly down-canyon and mostly concentrated during storm-induced downwelling and dense water cascading events. During the high river discharge season most of the newly-supplied and resuspended sediment remained stored on theshelf.However,duringthelateFebruarystormandcascadingevent,thestoredsedimentwasquicklyresuspendedandtransported, mainly through the westernmost submarine canyon (Cap de Creus), following a flushing pattern. Later, although minor storms and shelfdensewatercascadinghardlyincreasedsuspendedsedimentconcentrationswithintheCanyons,theyinducedstrongnear-bottom current velocities, increasing down-canyon sediment fluxes and generating small but significant sediment transport events. Most of the shelf-canyon transfer took place during the late February storm and cascading event through the Cap de Creus canyon where the net suspended sediment flux was between one and two orders of magnitude higher than in the other Canyons.

Pere Puig - One of the best experts on this subject based on the ideXlab platform.

  • spatial distribution of sedimentation rate increases in blanes canyon caused by technification of bottom trawling fleet
    Progress in Oceanography, 2018
    Co-Authors: Sarah Paradis, Pere Puig, Antoni Calafat, Pere Masqué, Anna Sanchezvidal, Jordi Garciaorellana, Miquel Canals
    Abstract:

    Abstract A detailed study of 15 sediment cores from Blanes Canyon and its immediate surroundings (NW Mediterranean Sea) was conducted to compare historic sedimentation rates and evaluate the possible impact of bottom-trawling intensification on the sedimentary regimes over the past 50 years. The canyon axis and flanks, as well as the adjacent open slope, were sampled at water depths ranging from 300 m to 2200 m. Grain size, dry bulk density, and 210Pb concentration profiles were measured to assess possible changes in sedimentation rates over the last century and their temporal and spatial relationship to bottom trawling effort. Sedimentation rates in the upper canyon axis (900–1200 m) had the highest rates of 0.9–2.1 cm·yr−1, quantified since the 1970s. Farther downcanyon, sedimentation rates increased two to five times after the 1970s, from 0.1–0.2 cm·yr−1 to 0.2–0.8 cm·yr−1, which coincides with a rapid growth of the total engine power of the fishing fleet operating in the study area. The enhanced sedimentation rates occur downslope of the main fishing grounds and decrease downcanyon as the distance from trawling grounds increases. These results highlight the ability of bottom trawling to resuspend bottom sediments, leading to net erosion of the canyon rims and flanks. In turn, large volumes of sediment are advected towards the canyon’s interior, ultimately increasing sediment deposition along the canyon axis. Natural sedimentation rates at similar along-canyon distance from shore in the untrawled continental slope (900–1500 m) and in the lower canyon axis (1500–2200 m) are comparable (0.08–0.20 cm·yr−1), suggesting distance from coastal sediment sources as the main control on regional sedimentation in deeper parts of the margin. While submarine Canyons have been regarded as preferential cross-margin conduits for sediment dispersal, they can also potentially function as modern depocenters for trawling-induced sedimentation.

  • Bottom-trawling along submarine Canyons impacts deep sedimentary regimes.
    Scientific Reports, 2017
    Co-Authors: Sarah Paradis, Jacobo Martín, Pere Puig, Pere Masqué, Xènia Juan-díaz, Albert Palanques
    Abstract:

    Many studies highlight that fish trawling activities cause seafloor erosion, but the assessment of the remobilization of surface sediments and its relocation is still not well documented. These impacts were examined along the flanks and axes of three headless submarine Canyons incised on the Barcelona continental margin, where trawling fleets have been operating for decades. Trawled grounds along canyon flanks presented eroded and highly reworked surface sediments resulting from the passage of heavy trawling gear. Sedimentation rates on the upper canyon axes tripled and quadrupled its natural (i.e. pre-industrialization) values after a substantial increase in total horsepower of the operating trawling fleets between 1960 s and 1970 s. These impacts affected the upper canyon reaches next to fishing grounds, where sediment resuspended by trawling can be transported towards the canyon axes. This study highlights that bottom trawling has the capacity to alter natural sedimentary environments by promoting sediment-starved canyon flanks, and by enhancing sedimentation rates along the contiguous axes, independently of Canyons’ morphology. Considering the global mechanisation and offshore expansion of bottom trawling fisheries since the mid-20th century, these sedimentary alterations may occur in many trawled Canyons worldwide, with further ecological impacts on the trophic status of these non-resilient benthic communities.

  • contemporary sediment transport processes in submarine Canyons
    Annual Review of Marine Science, 2014
    Co-Authors: Pere Puig, Albert Palanques, Jacobo Martín
    Abstract:

    Submarine Canyons are morphological incisions into continental margins that act as major conduits of sediment from shallow- to deep-sea regions. However, the exact mechanisms involved in sediment transfer within submarine Canyons are still a subject of investigation. Several studies have provided direct information about contemporary sedimentary processes in submarine Canyons that suggests different modes of transport and various triggering mechanisms. Storm-induced turbidity currents and enhanced off-shelf advection, hyperpycnal flows and failures of recently deposited fluvial sediments, dense shelf-water cascading, canyon-flank failures, and trawling-induced resuspension largely dominate present-day sediment transfer through Canyons. Additionally, internal waves periodically resuspend ephemeral deposits within Canyons and contribute to dispersing particles or retaining and accumulating them in specific regions. These transport processes commonly deposit sediments in the upper- and middle-canyon reaches ...

  • Sediment-Transport Processes in Submarine Canyons
    2014
    Co-Authors: Pere Puig, Albert Palanques, Jacobo Mart
    Abstract:

    Submarine Canyons are morphological incisions into continental margins that act as major conduits of sediment from shallow- to deep-sea regions. However, the exact mechanisms involved in sediment transfer within submarine Canyons are still a subject of investigation. Several studies have provided direct information about contemporary sedimentary processes in submarine Canyons that suggests different modes of transport and various triggering mechanisms. Storm-induced turbidity currents and enhanced off-shelf advection, hyperpycnal flows and failures of recently deposited fluvial sediments, dense shelf-water cascading, canyon-flank failures, and trawling-induced resuspension largely dominate present-day sediment transfer through Canyons. Additionally, internal waves periodically resuspend ephemeral deposits within Canyons and contribute to dispersing particles or retaining and accumulating them in specific regions. These transport processes commonly deposit sediments in the upper- and middle-canyon reaches for decades or centuries before being completely or partially flushed farther down-canyon by large sediment failures.

  • Suspended sediment fluxes and transport processes in the Gulf of Lions submarine Canyons. The role of storms and dense water cascading
    Marine Geology, 2006
    Co-Authors: Albert Palanques, Pere Puig, Miquel Canals, Antoni Calafat, Xavier Durrieu De Madron, Serge Heussner, Joan Fabres, Jorge Guillén, Jérôme Bonnin
    Abstract:

    Contemporary suspended sediment transport was studied in seven submarine Canyons of the Gulf of Lions (GoL). Current meters equipped with turbidity sensors were moored 4 m above bottom at 300 m depth in the canyon axis from November 2003 to May 2004. Sediment transport events were monitored and studied in relation to forcing conditions. There was a large flood in early December, during which discharges from all of the coastal rivers increased by more than one order of magnitude. A smaller flood of the Rhone River occurred later in mid-January followed by a persistent high river discharge that lasted until mid-February. There were also several E–SE storm events during the measurement period, two of them causing large swell, one in early December (max Hs: 8.4 m), coinciding with the major river flood,andoneinlateFebruary(maxHs:7m)duringaperiodoflowerriverdischarge.Mostofthevariabilityindown-canyoncurrentspeeds waslinkedtostrongdownwellinginducedbyE–SEstormsandtocascadingofdenseshelfwaterinducedbyNandNWwinds.Theintensity and timing of these processes strongly varied spatially. Eastern storms generated higher waves and induced stronger downwelling in the western than in the eastern sector of the GoL. Shelf dense water cascading events were enhanced during eastern storms and they were also more intense in the western sector of the GoL. These events occurred frequently from January to May along the western Canyons and from February to April along the eastern Canyons. From February to April they occurred simultaneously in all the Canyons. Sediment transport was mainly down-canyon and mostly concentrated during storm-induced downwelling and dense water cascading events. During the high river discharge season most of the newly-supplied and resuspended sediment remained stored on theshelf.However,duringthelateFebruarystormandcascadingevent,thestoredsedimentwasquicklyresuspendedandtransported, mainly through the westernmost submarine canyon (Cap de Creus), following a flushing pattern. Later, although minor storms and shelfdensewatercascadinghardlyincreasedsuspendedsedimentconcentrationswithintheCanyons,theyinducedstrongnear-bottom current velocities, increasing down-canyon sediment fluxes and generating small but significant sediment transport events. Most of the shelf-canyon transfer took place during the late February storm and cascading event through the Cap de Creus canyon where the net suspended sediment flux was between one and two orders of magnitude higher than in the other Canyons.

Miquel Canals - One of the best experts on this subject based on the ideXlab platform.

  • spatial distribution of sedimentation rate increases in blanes canyon caused by technification of bottom trawling fleet
    Progress in Oceanography, 2018
    Co-Authors: Sarah Paradis, Pere Puig, Antoni Calafat, Pere Masqué, Anna Sanchezvidal, Jordi Garciaorellana, Miquel Canals
    Abstract:

    Abstract A detailed study of 15 sediment cores from Blanes Canyon and its immediate surroundings (NW Mediterranean Sea) was conducted to compare historic sedimentation rates and evaluate the possible impact of bottom-trawling intensification on the sedimentary regimes over the past 50 years. The canyon axis and flanks, as well as the adjacent open slope, were sampled at water depths ranging from 300 m to 2200 m. Grain size, dry bulk density, and 210Pb concentration profiles were measured to assess possible changes in sedimentation rates over the last century and their temporal and spatial relationship to bottom trawling effort. Sedimentation rates in the upper canyon axis (900–1200 m) had the highest rates of 0.9–2.1 cm·yr−1, quantified since the 1970s. Farther downcanyon, sedimentation rates increased two to five times after the 1970s, from 0.1–0.2 cm·yr−1 to 0.2–0.8 cm·yr−1, which coincides with a rapid growth of the total engine power of the fishing fleet operating in the study area. The enhanced sedimentation rates occur downslope of the main fishing grounds and decrease downcanyon as the distance from trawling grounds increases. These results highlight the ability of bottom trawling to resuspend bottom sediments, leading to net erosion of the canyon rims and flanks. In turn, large volumes of sediment are advected towards the canyon’s interior, ultimately increasing sediment deposition along the canyon axis. Natural sedimentation rates at similar along-canyon distance from shore in the untrawled continental slope (900–1500 m) and in the lower canyon axis (1500–2200 m) are comparable (0.08–0.20 cm·yr−1), suggesting distance from coastal sediment sources as the main control on regional sedimentation in deeper parts of the margin. While submarine Canyons have been regarded as preferential cross-margin conduits for sediment dispersal, they can also potentially function as modern depocenters for trawling-induced sedimentation.

  • Submarine Canyons and gullies
    Submarine Geomorphology, 2017
    Co-Authors: David Amblas, Peter T. Harris, Miquel Canals, Veerle A I Huvenne, Thomas P. Gerber, S. Ceramicola, Francesco Latino Chiocci, Julian A. Dowdeswell, Steven Yueh Jen Lai, Galderic Lastras
    Abstract:

    Submarine Canyons are deep incisions observed along most of the world’s continental margins. Their topographic relief is as dramatic as that of any canyon or river valley on land but is hidden beneath the surface of the ocean. Our knowledge of Canyons has therefore come primarily from remote sensing and sampling, and has involved contributions from various oceanographic disciplines. Canyons are a critical link between coastal and shelf waters and abyssal depths; water masses, sediment, nutrients, and even litter and pollutants are carried through them. Advances in technology continue to provide new insights into canyon environments by pushing the frontier of deep marine observations and measurements. In this chapter we describe the main geomorphic features of submarine Canyons and what is known about their formation and the processes that shape them. We also consider submarine gullies, which are small valleys commonly found within or alongside submarine Canyons on the continental slope and may represent an incipient stage of canyon development.

  • Geomorphic response of submarine Canyons to tectonic activity: Insights from the Cook Strait canyon system, New Zealand
    Geosphere, 2014
    Co-Authors: Aaron Micallef, Miquel Canals, Joshu J Mountjoy, Philip M Barnes, Galderic Lastras
    Abstract:

    Active margins host more than half of submarine Canyons worldwide. Understanding the coupling between active tectonics and canyon processes is required to improve modeling of canyon evolution and derive tectonic information from canyon morphology. In this paper we analyze high-resolution geophysical data and imagery from the Cook Strait canyon system (CS), offshore New Zealand, to characterize the influence of active tectonics on the morphology, processes, and evolution of submarine Canyons, and to deduce tectonic activity from canyon morphology. Canyon location and morphology bear the clearest evidence of tectonic activity, with major faults and structural ridges giving rise to sinuosity, steep and linear longitudinal profiles, cross-sectional asymmetry, and breaks in slope gradient, relief, and slope-area plots. Faults are also associated with stronger and more frequent sedimentary flows, steep canyon walls that promote gully erosion, and seismicity that is considered the most likely trigger of failure of canyon walls. Tectonic activity gives rise to two types of knickpoints in the CS. Gentle, rounded and diffusive knickpoints form due to short-wavelength folds or fault breakouts. The more widespread steep and angular knickpoints have migrated through canyon-floor slope failures and localized quarrying and/or plucking. Migration is driven by base-level lowering due to regional margin uplift and deepening of the lower Cook Strait Canyon, and is likely faster in larger Canyons because of higher sedimentary flow throughput. The knickpoints, nonadherence to Playfair’s Law, linear longitudinal profiles, and lack of canyon-wide, inverse power law slope-area relationships indicate that the CS is in a transient state, adjusting to perturbations associated with tectonic displacements and changes in base level and sediment fluxes. We conclude by inferring unmapped faults and regions of more pronounced uplift, and proposing a generalized model for canyon geomorphic evolution in tectonically active margins.

  • Suspended sediment fluxes and transport processes in the Gulf of Lions submarine Canyons. The role of storms and dense water cascading
    Marine Geology, 2006
    Co-Authors: Albert Palanques, Pere Puig, Miquel Canals, Antoni Calafat, Xavier Durrieu De Madron, Serge Heussner, Joan Fabres, Jorge Guillén, Jérôme Bonnin
    Abstract:

    Contemporary suspended sediment transport was studied in seven submarine Canyons of the Gulf of Lions (GoL). Current meters equipped with turbidity sensors were moored 4 m above bottom at 300 m depth in the canyon axis from November 2003 to May 2004. Sediment transport events were monitored and studied in relation to forcing conditions. There was a large flood in early December, during which discharges from all of the coastal rivers increased by more than one order of magnitude. A smaller flood of the Rhone River occurred later in mid-January followed by a persistent high river discharge that lasted until mid-February. There were also several E–SE storm events during the measurement period, two of them causing large swell, one in early December (max Hs: 8.4 m), coinciding with the major river flood,andoneinlateFebruary(maxHs:7m)duringaperiodoflowerriverdischarge.Mostofthevariabilityindown-canyoncurrentspeeds waslinkedtostrongdownwellinginducedbyE–SEstormsandtocascadingofdenseshelfwaterinducedbyNandNWwinds.Theintensity and timing of these processes strongly varied spatially. Eastern storms generated higher waves and induced stronger downwelling in the western than in the eastern sector of the GoL. Shelf dense water cascading events were enhanced during eastern storms and they were also more intense in the western sector of the GoL. These events occurred frequently from January to May along the western Canyons and from February to April along the eastern Canyons. From February to April they occurred simultaneously in all the Canyons. Sediment transport was mainly down-canyon and mostly concentrated during storm-induced downwelling and dense water cascading events. During the high river discharge season most of the newly-supplied and resuspended sediment remained stored on theshelf.However,duringthelateFebruarystormandcascadingevent,thestoredsedimentwasquicklyresuspendedandtransported, mainly through the westernmost submarine canyon (Cap de Creus), following a flushing pattern. Later, although minor storms and shelfdensewatercascadinghardlyincreasedsuspendedsedimentconcentrationswithintheCanyons,theyinducedstrongnear-bottom current velocities, increasing down-canyon sediment fluxes and generating small but significant sediment transport events. Most of the shelf-canyon transfer took place during the late February storm and cascading event through the Cap de Creus canyon where the net suspended sediment flux was between one and two orders of magnitude higher than in the other Canyons.

  • The Role of Canyons on Strata Formation
    Oceanography, 2004
    Co-Authors: Miquel Canals, Serge Berné, Galderic Lastras, Jose Luis Casamor, André Monaco, Juan Acosta, Benoit Loubrieu, Philip Weaver, Anthony Grehan, Bernard Dennielou
    Abstract:

    This paper provides a spatial and temporal multi-scale approach of European submarine Canyons. We first present the long-term geologic view of European margins as related to controls on submarine canyon development. Then we discuss the extent to which submarine canyon systems resemble river systems because both essentially form drainage networks. Finally, we deal with the shortest-term, highest-resolution scale to get a flavor of the current functioning and health of modern submarine Canyons in the northwestern Mediterranean Sea