Gravity-driven sediment transport on the continental shelf: implications for equilibrium profiles near river mouths

Friedrichs, Carl T.; Wright, L. D.

doi:10.1016/j.coastaleng.2004.07.010

Cited by 134 publications

(116 citation statements)

References 22 publications

Supporting

Mentioning

107

Contrasting

Order By: Relevance

“…Nevertheless, it still indicates that sediments off the Rhône River are reactive enough to display stationary conditions one month after a flood event. This time scale is in agreement with flood event studies in other coastal environments which evidenced relaxation time scales around weeks (Bentley and Nittrouer, 2003;Eyre and Ferguson, 2006;Eyre and Twigg, 1997;Deflandre et al, 2002). Re-establishment of bacterial community could be one of the driving mechanisms as the time scales involved are also in the order of weeks (Boer et al, 2009;Aller and Aller, 2004), in agreement with our data.…”

Section: Temporal Variability Of Sediment Oxygen Uptake: Flood Dischasupporting

confidence: 92%

“…This is in agreement with a study of the Po River flood in 2000 (Dell'Anno et al, 2008) who observed a decrease of OM degradation rates in coastal sediments from the Northern Adriatic. Similarly, a drop in benthic community respiration was observed after a flood in south-eastern Australian rivers (Rees et al, 2005) and in the Australian subtropical Brunswick estuary (Eyre et al, 2006). Authors argued that the flood scoured the sediment, leaving a poor carbon content layer to be degraded.…”

Section: Temporal Variability Of Sediment Oxygen Uptake: Flood Dischamentioning

confidence: 95%

“…The hydrological regime of the Rhône River shows strong seasonal contrast with a large difference between low (<500 m 3 s −1 ) and high (>3000 m 3 s −1 ) water-discharge (Pont et al, 2002). Large amounts of terrestrial muddy sediments accumulate in the wide prodelta off the Rhône river mouth, extending then the shoreline to 60 m depth (Friedrichs and Wright, 2004). Net sedimentation rates in the prodelta are up to 50 cm yr −1 at the river mouth (Charmasson et al, 1998) and decrease rapidly offshore on the continental shelf, i.e.…”

Section: Study Areamentioning

confidence: 99%

See 2 more Smart Citations

Temporal variability of carbon recycling in coastal sediments influenced by rivers: assessing the impact of flood inputs in the Rhône River prodelta

et al. 2010

View full text Add to dashboard Cite

Abstract. River deltas are particularly important in the marine carbon cycle as they represent the transition between terrestrial and marine carbon: linked to major burial zones, they are reprocessing zones where large carbon fluxes can be mineralized. In order to estimate this mineralization, sediment oxygen uptake rates were measured in continental shelf sediments and river prodelta over different seasons near the outlet of the Rhône River in the Mediterranean Sea. On a selected set of 10 stations in the river prodelta and nearby continental shelf, in situ diffusive oxygen uptake (DOU) and laboratory total oxygen uptake (TOU) measurements were performed in early spring and summer 2007 and late spring and winter 2008. In and ex situ DOU did not show any significant differences except for shallowest organic rich stations. Sediment DOU rates show highest values concentrated close to the river mouth (approx. 20 mmol O 2 m −2 d −1 ) and decrease offshore to values around 4.5 mmol O 2 m −2 d −1 with lowest gradients in a south west direction linked to the preferential transport of the finest riverine material. Core incubation TOU showed the same spatial pattern with an averaged TOU/DOU ratio of 1.2±0.4. Temporal variations of sediment DOU over different sampling periods, spring summer and late fall, were limited and benthic mineralization rates presented a stable spatial pattern.Correspondence to: C. Cathalot (cecile.cathalot@lsce.ipsl.fr) A flood of the Rhône River occurred in June 2008 and delivered up to 30 cm of new soft muddy deposit. Immediately after this flood, sediment DOU rates close to the river mouth dropped from around 15-20 mmol O 2 m −2 d −1 to values close to 10 mmol O 2 m −2 d −1 , in response to the deposition near the river outlet of low reactivity organic matter associated to fine material. Six months later, the oxygen distribution had relaxed back to its initial stage: the initial spatial distribution was found again underlining the active microbial degradation rates involved and the role of further deposits. These results highlight the immediate response of the sediment oxygen system to flood deposit and the rapid relaxation of this system towards its initial state (6 months or less) potentially linked to further deposits of reactive material.

show abstract

Section: Temporal Variability Of Sediment Oxygen Uptake: Flood Dischasupporting

confidence: 92%

Section: Temporal Variability Of Sediment Oxygen Uptake: Flood Dischamentioning

confidence: 95%

Section: Study Areamentioning

confidence: 99%

See 1 more Smart Citation

Temporal variability of carbon recycling in coastal sediments influenced by rivers: assessing the impact of flood inputs in the Rhône River prodelta

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Seafloor sampling studies on the Eel shelf showed that the flood deposits emplaced by wave-supported turbidity flow had a stratigraphic signature consisting of relativity thick deposits (5 to 15 cm) of terrigenous mud (Wheatcroft and Borgeld, 2000). Modeling of deposition due to wave-supported turbidity flows suggests that these flows could potentially establish a strong feedback mechanism with shelf morphology, and that this process could control the shape of the shelf-slope clinoforms (Friedrichs and Wright, 2004).…”

Section: Introductionmentioning

confidence: 99%

Observations and modeling of wave-supported sediment gravity flows on the Po prodelta and comparison to prior observations from the Eel shelf

Traykovski

Wiberg

Geyer

2007

Continental Shelf Research

181

195

View full text Add to dashboard Cite

Abstract:A mooring and tripod array was deployed from the fall of 2002 through the spring of 2003 on the Po prodelta to measure sediment transport processes associated with sediment delivered from the Po River. Observations on the prodelta revealed wave-supported gravity flows of high concentration mud suspensions that are dynamically and kinematically similar to those observed on the Eel shelf . Due to the dynamic similarity between the two sites, a simple one-dimensional across-shelf model with the appropriate bottom boundary condition was used to examine fluxes associated with this transport mechanism at both locations. To calculate the sediment concentrations associated with the wave-dominated and wave-current resuspension, a bottom boundary condition using a reference concentration was combined with an "active layer" formulation to limit the amount of sediment in suspension. Whereas the wave-supported gravity flow mechanism dominates the transport on the Eel shelf, on the Po prodelta flux due to this mechanism is equal in magnitude to transport due to wave resuspension and wind-forced mean currents in cross-shore direction. Southward transport due to wave resuspension and wind forced mean currents move an order of magnitude more sediment along-shore than the downslope flux associated wave-supported gravity flows.

show abstract

“…A decrease in slope angle with time, in association, 4 records a progressive approach to the equilibrium profile, compensating the initial steep slope (e.g., Friedrichs & Wright, 2004). Considering the depositional conditions during the interval, post-slump physiography and maintenance of high-sediment supply during forced regressions controlled the geometry and high angle of the clinoforms formed just after slope failure (e.g., Zecchin & Catuneanu, 2013;Safronova et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Seismic expression of depositional elements associated with a strongly progradational shelf margin: northern Santos Basin, southeastern Brazil

Berton

Vesely

2016

Braz. J. Geol.

View full text Add to dashboard Cite

Seismic facies analysis and seismic geomorphology are important tools for the analysis of depositional elements in subsurface. This paper aimed to investigate the character and genesis of depositional elements and erosive features associated with an Eocene progradational shelf margin in northern Santos Basin. Identified seismic facies are interpreted as shelf-margin deltas/shoreface deposits, tangential (oblique) clinoforms, sigmoidal clinoforms, topset reflectors, mass-transport deposits and turbidites. These facies are grouped into four associations representing periods of relatively constant environmental conditions. Association 1 is composed of shelf-margin deltas/shoreface deposits, tangential clinoforms and extensive sand--rich turbidites disposed as submarine channels and frontal splays. A progressive increase in clinoform angle within this association has been identified, culminating in high-relief sigmoidal clinoforms with less voluminous turbidites of facies association 2. Association 3 is composed by subparallel to divergent topset reflectors, interpreted as continental to shelfal deposits placed during base-level rises. These are always truncated basinward by slump scars, formed as a consequence of sediment overload at the shelf margin during aggradations. Association 4 is composed of sigmoidal clinoforms, mass-transport deposits and turbidites. Early clinoforms are steeper as a consequence of the topography of the slump scars. Subsequently, dip angles become progressively gentler as the system approach to the equilibrium profile. The steep physiography was favorable for canyon incision, which played an important role in turbidite deposition. Mass-transport deposits, formed subsequent to slope collapse, are composed of mud-rich diamictites, and show strong internal deformation.KEYWORDS: Seismic facies; Seismic geomorphology; Deep-marine deposition; Mass-transport deposits; Turbidite systems. RESUMO: A análise de fácies sísmicas e a geomorfologia sísmica são ferramentas importantes para o estudo de elementos deposicionais em subsuperfície. Neste trabalho foram avaliadas as características e a gênese de elementos deposicionais e de feições erosivas associadas a uma margem progradante desenvolvida no Eoceno no norte da bacia de

show abstract

Gravity-driven sediment transport on the continental shelf: implications for equilibrium profiles near river mouths

Cited by 134 publications

References 22 publications

Temporal variability of carbon recycling in coastal sediments influenced by rivers: assessing the impact of flood inputs in the Rhône River prodelta

Temporal variability of carbon recycling in coastal sediments influenced by rivers: assessing the impact of flood inputs in the Rhône River prodelta

Observations and modeling of wave-supported sediment gravity flows on the Po prodelta and comparison to prior observations from the Eel shelf

Seismic expression of depositional elements associated with a strongly progradational shelf margin: northern Santos Basin, southeastern Brazil

Contact Info

Product

Resources

About