Oceanic flood deposits on the northern California shelf: large-scale distribution and small-scale physical properties

Wheatcroft, Robert A.; Borgeld, Jeffry C.

doi:10.1016/s0278-4343(00)00066-2

Cited by 170 publications

(162 citation statements)

References 37 publications

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“…The predicted location of the deposit between 50 and 100 m water depths for this 1998 data set is consistent with the location of flood deposits measured by seabed observations after major Eel River flood events during the winters of 1995 and 1997. Seabed sampling in March of 1998 did not reveal a measurable flood deposit (Wheatcroft and Borgeld, 2000). However, this seabed sampling occurred several months after the 1998 depositional events and subsequent erosional events were observed in the ABS time series before the seabed sampling cruises .…”

Section: Across-shelf Model Runs For the Eel Site And Comparison To Dmentioning

confidence: 85%

“…On the Eel shelf, observations of the Eel River plume, boundary layer sediment transport processes, and the distribution of seafloor sediment properties revealed that wave-supported turbidity flows were the dominant mechanisms for creating midshelf flood deposits. Tripod and hydrographic survey observations showed that the Eel River delivered sediment to the inner shelf and that wave-supported turbidity flows were responsible for transporting to a depositional locus in 60 to 100 m water depths (Wheatcroft et al, 1996(Wheatcroft et al, , 1997Wheatcroft and Borgeld, 2000). 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).…”

Section: Introductionmentioning

confidence: 99%

“…Tripod and hydrographic survey observations showed that the Eel River delivered sediment to the inner shelf and that wave-supported turbidity flows were responsible for transporting to a depositional locus in 60 to 100 m water depths (Wheatcroft et al, 1996(Wheatcroft et al, , 1997Wheatcroft and Borgeld, 2000). 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%

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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

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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.

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Section: Across-shelf Model Runs For the Eel Site And Comparison To Dmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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

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“…These inputs are highly variable over time, ranging from low river discharges and low sediment inputs to the occurrence of flood events with high sediment supplies (Wheatcroft and Borgeld, 2000).…”

Section: Introductionmentioning

confidence: 99%

Biogeochemical characterization of the riverine particulate organic matter transferred to the NW Mediterranean Sea

et al. 2014

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Abstract.A large amount of terrestrial organic matter is annually delivered by rivers to the continental shelf, where this material is either degraded, buried or transferred to the deep sea by hydrodynamic processes such as storms. The relative amount of terrestrial organic matter in the marine sediments is often determined by analysing the stable isotopes (δ 13 C and δ 15 N) and the C / N ratio of organic matter because the various particulate organic matter (POM) sources have distinct isotopic compositions. With the objective to refine and better interpret POM sources in the marine environment, we have characterized monthly terrestrial POM delivered by eight rivers discharging to the NW Mediterranean Sea: the Rhône, Hérault, Orb, Aude, Têt, Fluvià, Ter and Tordera rivers. These rivers were simultaneously sampled from November 2008 to December 2009 and the concentrations of total suspended matter (TSM), particulate organic carbon (POC) and nitrogen (PN), as well as their stable isotopic ratios (δ 13 C and δ 15 N) were determined.During the survey, three rainstorm events with winds coming from the E-NE and the S-SE impacted the NW Mediterranean. Depending on the direction of incoming winds, the fluvial response (amount of water discharge and TSM) was different. Rivers draining the Alps (Rhône River) and Central Massif (Hérault, Orb, and Aude rivers) were mostly impacted by rainstorms associated with winds coming from the S-SE, while rivers draining the Pyrenees (Têt, Fluvià, and Ter rivers) and the Montseny Massif (Tordera River) were impacted by rainstorms associated with winds coming from the E-NE. In addition, the spatial evolution of water discharges shows a different hydrological regime of the Rhône River, with relatively constant and high water stages and TSM concentrations when compared to coastal rivers, characterized by long periods of low water stages. TSM concentrations are positively correlated to water discharges (high water flows resuspended riverbed sediments) but show an inverse relationship with POC and PN relative contents (mostly due to dilution and by low availability of light in river waters during flood events). TSM in most of the coastal rivers have on average 2.5-3 times higher POC and PN mean contents than the Rhône River (8.5 and 1.5 %, respectively, for coastal rivers compared to 3.6 and 0.5 %, respectively, for the Rhône River). This discrepancy may be caused by the long drought periods in small coastal Mediterranean watersheds that enhance the eutrophication in studied coastal rivers. The δ 13 C ratios of organic matter also reflect this discrepancy between high and low water stages with values ranging from −33.2 to −24.5 ‰. The enriched 13 C values (−26.3 ± 0.4 ‰ for the Rhône River and −26.9 ± 1.2 ‰ for coastal rivers), measured during high water stages, express mostly a mixture of terrestrial source (plant remains and soils) whereas

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“…General tendency of SSC is similar to that in a tide-dominated estuary. Stow et al 1985, Bennett and Hulbert 1986, Kuehl et al 1986, Dukat and Kuehl 1995, Jaeger and Nittrouer 1995, Wheatcroft and Borgeld 2000, Collinson et al 2006, and MacEachern et al 2007 . Muddy deposit from relatively low suspended-sediment concentration SSC initially 2 g /L exhibits random-oriented structure characterized by edge-to-face E-F and edge-to-edge E-E contacts of individual clay particle A, B .…”

mentioning

confidence: 99%

Fluid mud: Distinctive features and implications for genetic stratigraphy

Nishida

Itô

2009

Jour. Geol. Soc. Japan

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Oceanic flood deposits on the northern California shelf: large-scale distribution and small-scale physical properties

Cited by 170 publications

References 37 publications

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

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

Biogeochemical characterization of the riverine particulate organic matter transferred to the NW Mediterranean Sea

Fluid mud: Distinctive features and implications for genetic stratigraphy

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