Interannual variability of nearbed sediment flux on the Eel River shelf, northern California

Ogston, A. S.; Guerra, Josefa Varela; Sternberg, Richard W.

doi:10.1016/j.csr.2003.08.007

Cited by 33 publications

(16 citation statements)

References 33 publications

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“…In open-shelf environments, waves are usually the dominant control on the frequency and duration of sediment resuspension and transport (Komar et al, 1972;Drake & Cacchione, 1985;Ogston et al, 2004). Current-generated bed stresses (tidal or wind driven) typically are not large enough to mobilize sediment in the absence of wave-generated bed stresses.…”

Section: Fluid Forcingmentioning

confidence: 99%

“…12a) Year day 1995 (c) calculated current and bed (combined wave-current skin friction) shear velocities; (d) suspended-sediment concentration 30 cmab (grey line), with a low-pass, 35-hr filter (red line); (e) calculated resuspension depth (the depth of the layer that would be formed if all sediment in suspension were deposited on the bed with the average porosity of the seabed) during the autumn-winter of 1995 at station S60 (e.g. Ogston et al, 2004). The horizontal lines at an orbital velocity of 0.14 m s −1 in (b) and a shear velocity of 1.1 cm s −1 in (c) represent an estimate of the threshold for resuspension.…”

Section: H T Sinh(2πh/l)mentioning

confidence: 99%

“…Although tidal currents comprise a large portion of the velocity variance on the Eel shelf, the net sediment flux associated with them may be relatively small owing to their directional reversal over periods that are short compared with the duration of typical resuspension events (i.e. there may be a high instantaneous flux, but little net flux over the tidal cycle; Ogston et al, 2004). However, increases in suspended-sediment concentrations in the bottom boundary layer associated with tidally induced turbulent mixing can significantly increase the volume of sediment in suspension and therefore the net flux due to subtidal currents.…”

Section: Currentsmentioning

confidence: 99%

“…For example, on the Eel shelf, net sediment flux along the shelf appears to be controlled by the frequency structure in the very low frequency bands (weeks to months). This structure changes from year to year, hypothetically due to changes in the eddy structure formed over the shelf and slope as the result of pressure gradients and topographic interferences (Ogston et al, 2004).…”

Section: Currentsmentioning

confidence: 99%

“…In the STRATAFORM study several events were 'caught' while they were happening, The star marks the location of the long-term monitoring tripod at station S60 (e.g. Ogston et al, 2004) and the heavy black line encloses the approximate location of the 1995 and 1997 flood deposits (Wheatcroft & Borgeld, 2000). Station locations discussed in the text are referenced by a letter designation corresponding to shore-normal transects and nominal water depths (i.e.…”

Section: Introduction and Scopementioning

confidence: 99%

See 4 more Smart Citations

Post‐Depositional Alteration and Preservation of Sedimentary Strata

Wheatcroft

Wiberg

Alexander

et al. 2007

Continental Margin Sedimentation

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All sediment that is delivered to the seabed is subject to post-depositional alteration before it becomes part of the preserved stratigraphic record. Physical and biological processes occurring in the upper few decimetres of the seabed alter newly deposited sediment, thereby creating the fine-scale sedimentary record. The geographical region of focus is the Eel margin of northern California, where a combination of high precipitation, frequent winter storms and intense benthic biological processes exert fundamental controls on the fine-scale stratigraphy. Major findings are that:1 although the wave conditions on the Eel shelf are highly energetic, only a few millimetres to one or two centimetres of bed material are typically put in suspension during storms; 2 despite a high initial porosity (i.e. low strength), flood beds quickly become resistant to erosion; 3 shelf macrofauna show considerable resilience to deposition of flood sediment; 4 storm deposits have a low preservation potential on open continental margins; 5 episodic sedimentation is key to preservation of strata and signals produced by flood and storm events.Future insight into post-depositional alteration will benefit from focused observations and theoretical modelling that explicitly couple physical and biological processes on multiple time-scales.

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Section: Fluid Forcingmentioning

confidence: 99%

Section: H T Sinh(2πh/l)mentioning

confidence: 99%

Section: Currentsmentioning

confidence: 99%

Section: Currentsmentioning

confidence: 99%

Section: Introduction and Scopementioning

confidence: 99%

See 3 more Smart Citations

Post‐Depositional Alteration and Preservation of Sedimentary Strata

Wheatcroft

Wiberg

Alexander

et al. 2007

Continental Margin Sedimentation

View full text Add to dashboard Cite

show abstract

Recent Advances in Understanding Continental Shelf Sediment Transport

Wright

2012

Sediments, Morphology and Sedimentary Processes on Continental Shelves

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Writing a Rosetta Stone: Insights into Continental‐Margin Sedimentary Processes and Strata

Nittrouer

Austin

Field

et al. 2007

Continental Margin Sedimentation

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Continental margins are valuable for many reasons, including the rich record of Earth history that they contain. A comprehensive understanding about the fate of fluvial sediment requires knowledge that transcends time-scales ranging from particle transport to deep burial. Insights are presented for margins in general, with a focus on a tectonically active margin (northern California) and a passive margin (New Jersey). Formation of continental-margin strata begins with sediment delivery to the seabed. Physical and biological reworking alters this sediment before it is preserved by burial, and has an impact upon its dispersal to more distal locations. The seabed develops strength as it consolidates, but failure can occur and lead to sediment redistribution through high-concentration gravity flows. Processes ranging from sediment delivery to gravity flows create morphological features that give shape to continental-margin surfaces. With burial, these surfaces may become seismic reflectors, which are observed in the subsurface as stratigraphy and are used to interpret the history of formative processes. Observations document sedimentary processes and strata on a particular margin, but numerical models and laboratory experimentation are necessary to provide a quantitative basis for extrapolation of these processes and strata in time and space.

show abstract

Interannual variability of nearbed sediment flux on the Eel River shelf, northern California

Cited by 33 publications

References 33 publications

Post‐Depositional Alteration and Preservation of Sedimentary Strata

Post‐Depositional Alteration and Preservation of Sedimentary Strata

Recent Advances in Understanding Continental Shelf Sediment Transport

Writing a Rosetta Stone: Insights into Continental‐Margin Sedimentary Processes and Strata

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