Sediment transport to the deep canyons and open-slope of the western Gulf of Lions during the 2006 intense cascading and open-sea convection period

Palanqués, Albert; Puig, Pere; Madron, Xavier Durrieu de; Sánchez-Vidal, Anna; Pasqual, Catalina; Martín, Jacobo; Calafat, Antoni; Heussner, Serge; Canals, Miquel

doi:10.1016/j.pocean.2012.05.002

Cited by 68 publications

(86 citation statements)

References 60 publications

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“…Submarine canyons are widespread complex features along continental margins and are pathways for sediment transport to the deep basins (Piper and Savoye, 1993;Wynn et al, 2007;Palanques et al, 2012), They play a key role in hydrography, biogeochemistry and carbon cycle dynamics (Epping et al, 2002;Canals et al, 2006;Huvenne et al, 2011). Despite their importance, the processes of start-up, evolution and maintenance of submarine canyons remain poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Submarine canyons of north-western Sicily (Southern Tyrrhenian Sea): Variability in morphology, sedimentary processes and evolution on a tectonically active margin

Iacono

Sulli

Agate

2014

Deep Sea Research Part II: Topical Studies in Oceanography

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a b s t r a c tSwath-bathymetry, mono-channel and multi-channel seismic reflection records acquired during the last two decades on the northern Sicilian margin have unveiled a dense network of submarine canyons within the depth range of 80-2100 m. The canyons display a relevant variability in their geometry, morphology and sedimentary processes. The margin shows a young, tectonically active shelf to slope setting, linking the Sicilian-Maghrebian Thrust Belt to the Tyrrhenian oceanic realm, developed during the Neogene-Quaternary time span. The aim of this study is to highlight the main governing factors that contributed to the evolution and differentiation of the northern Sicilian canyons, mainly focusing on the Gulf of Palermo and on the Gulf of Castellammare. Tectonic control is more evident in the canyons of the Gulf of Palermo, with submarine landslides retrograding on a steep slope and mainly controlling their evolution. Otherwise, canyons, tributaries and gullies mapped in the Gulf of Castellammare developed on a less steep substrate and display sinuous to meandering paths, with a relevant role of coastal/shelf sedimentary inputs and downslope turbidity processes in their formation. Results suggest that, despite the geographically close proximity of the two study areas, the different structural settings of the Castellammare and Palermo Basins are mainly responsible for canyon variability. Data indicate likely ongoing uplift and tilting movements along the Sicilian margin, influencing the development of the studied canyons, which have probably been more active during the Quaternary glacial maxima than they are in the present day.

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Section: Introductionmentioning

confidence: 99%

Submarine canyons of north-western Sicily (Southern Tyrrhenian Sea): Variability in morphology, sedimentary processes and evolution on a tectonically active margin

Iacono

Sulli

Agate

2014

Deep Sea Research Part II: Topical Studies in Oceanography

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“…Most of the published literature on the off-shelf delivery of sediments through the CCC has focused on the impact of extreme events such as major floods and storms Bourrin et al, 2008), deep cascading , Pasqual et al, 2010Palanques et al, 2012) or the combination of them Ulses et al, 2008a;Ribó et al, 2011).…”

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confidence: 99%

Sediment transport along the Cap de Creus Canyon flank during a mild, wet winter

et al. 2013

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Cap de Creus Canyon (CCC) is known as a preferential conduit for particulate matter leaving the Gulf of Lion continental shelf towards the slope and the basin, particularly in winter when storms and dense shelf water cascading coalesce to enhance the seaward export of shelf waters. During the CASCADE (CAscading, Storm, Convection, Advection and Downwelling Events) cruise in March 2011, deployments of recording instruments within the canyon and vertical profiling of the water column properties were conducted to study with high spatial-temporal resolution the impact of such processes on particulate matter fluxes. In the context of the mild and wet 2010–2011 winter, no remarkable dense shelf water formation was observed. On the other hand, the experimental setup allowed for the study of the impact of E-SE storms on the hydrographical structure and the particulate matter fluxes in the CCC. The most remarkable feature in terms of sediment transport was a period of dominant E-SE winds from 12 to 16 March, including two moderate storms (maximum significant wave heights = 4.1–4.6 m). During this period, a plume of freshened, relatively cold and turbid water flowed at high speeds along the southern flank of the CCC in an approximate depth range of 150–350 m. The density of this water mass was lighter than the ambient water in the canyon, indicating that it did not cascade off-shelf and that it merely downwelled into the canyon forced by the strong cyclonic circulation induced over the shelf during the storms and by the subsequent accumulation of seawater along the coast. Suspended sediment load in this turbid intrusion recorded along the southern canyon flank oscillated between 10 and 50 mg L⁻¹, and maximum currents speeds reached values up to 90 cm s⁻¹. A rough estimation of 10⁵ tons of sediment was transported through the canyon along its southern wall during a 3-day-long period of storm-induced downwelling. Following the veering of the wind direction (from SE to NW) on 16 March, downwelling ceased, currents inside the canyon reversed from down- to up-canyon, and the turbid shelf plume was evacuated from the canyon, most probably flowing along the southern canyon flank and being entrained by the general SW circulation after leaving the canyon confinement. This study highlights that remarkable sediment transport occurs in the CCC, and particularly along its southern flank, even during mild and wet winters, in absence of cascading and under limited external forcing. The sediment transport associated with eastern storms like the ones described in this paper tends to enter the canyon by its downstream flank, partially affecting the canyon head region. Sediment transport during these events is not constrained near the seafloor but distributed in a depth range of 200–300 m above the bottom. Our paper broadens the understanding of the complex set of atmosphere-driven sediment transport processes acting in this highly dynamic area of the northwestern Mediterranean Sea

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“…No significant differences in bioavailable C concentrations with increasing water depth were observed either in the sediments of the Nazarè canyon or in those of Cap de Creus canyon. These results suggest that the lateral transport of organic particles from shallow to bathyal depths, even amplified by episodic events such as gravity flows in the Nazarè canyon and DSWC in the Catalan margin Canals et al, 2006;Palanques et al, 2006Palanques et al, , 2012de Stigter et al, 2007;Arzola et al, 2008), may have important implications on the quantity and distribution of bioavailable C pools in the sediments.…”

Section: Discussionmentioning

confidence: 91%

“…The head of Cap de Creus canyon is 12 km from the coastline and the canyon extends for 95 km basinwards till entering the deeper Sete canyon at about 2150 m depth. Recent studies conducted on the Catalan margin reported that Cap de Creus canyon represents a preferential pathway of particle transport for the entire Gulf of Lion and that dense shelf water cascading (DSWC) events occurring during winter periods represent one of the main mechanisms of sediment export towards deeper waters Sanchez-Vidal et al, 2008;Palanques et al, 2012). Two major DSWC events occurred in winter/early spring 2005 and 2006, a few months before the sediment sampling in October 2005 and August 2006.…”

Section: Study Areas and Sampling Strategymentioning

confidence: 99%

“…These events, driven by exceptionally strong, dry northern winds, spread down to the Catalan margin with maximum near-bottom current velocities of ca. 1 m s −1 Palanques et al, 2012) conveying large amounts of organic material into Cap de Creus canyon and the adjacent southern open slope Sanchez-Vidal et al, 2008Pasqual et al, 2010). Primary production in the Gulf of Lion ranges between 78 and 142 g C m −2 yr −1 (Lefevre et al, 1997).…”

Section: Study Areas and Sampling Strategymentioning

confidence: 99%

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Trophic state of benthic deep-sea ecosystems from two different continental margins off Iberia

et al. 2013

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The bioavailability of organic matter in benthic deep-sea ecosystems, commonly used to define their trophic state, can greatly influence key ecological processes such as biomass production and nutrient cycling. Here, we assess the trophic state of deep-sea sediments from open slopes and canyons of the Catalan (NW Mediterranean) and Portuguese (NE Atlantic) continental margins, offshore east and west Iberia, respectively, by using a biomimetic approach based on enzymatic digestion of protein and carbohydrate pools. Patterns of sediment trophic state were analyzed in relation to increasing water depth, including repeated samplings over a 3 yr period in the Catalan margin. Two out of the three sam- pling periods occurred a few months after dense shelf water cascading events. The benthic deep-sea ecosystems investi- gated in this study were characterized by high amounts of bioavailable organic matter when compared to other deep- sea sediments. Bioavailable organic matter and its nutritional value were significantly higher in the Portuguese margin than in the Catalan margin, thus reflecting differences in pri- mary productivity of surface waters reported for the two re- gions. Similarly, sediments of the Catalan margin were char- acterized by significantly higher food quantity and quality in spring, when the phytoplankton bloom occurs in surface wa- ters, than in summer and autumn. Differences in the benthic trophic state of canyons against open slopes were more ev- ident in the Portuguese than in the Catalan margin. In both continental margins, bioavailable organic C concentrations did not vary or increase with increasing water depth. Overall our findings suggest that the intensity of primary production processes along with the lateral transfer of organic particles, even amplified by episodic events, can have a role in controlling the quantity and distribution of bioavailable organic detritus and its nutritional value along these continental margin ecosystems

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Sediment transport to the deep canyons and open-slope of the western Gulf of Lions during the 2006 intense cascading and open-sea convection period

Cited by 68 publications

References 60 publications

Submarine canyons of north-western Sicily (Southern Tyrrhenian Sea): Variability in morphology, sedimentary processes and evolution on a tectonically active margin

Submarine canyons of north-western Sicily (Southern Tyrrhenian Sea): Variability in morphology, sedimentary processes and evolution on a tectonically active margin

Sediment transport along the Cap de Creus Canyon flank during a mild, wet winter

Trophic state of benthic deep-sea ecosystems from two different continental margins off Iberia

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