Sediment transport and deposition at river mouths: A synthesis

Wright, L. D.

doi:10.1130/0016-7606(1977)88<857:stadar>2.0.co;2

Cited by 572 publications

(421 citation statements)

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“…8, 10, 11 on sheet 8) indicates both vertical aggradation and low-angle seaward progradation. Bar morphology and internal structure are consistent with depositional patterns outlined by Wright (1977) for wave-dominated river mouths. Sediment cover thins gradually away from this delta-mouth bar to the south and west, and bedrock is exposed along the rim of Monterey Canyon to the west.…”

Section: Thickness and Depth To Base Of Uppermost Pleistocene And Holsupporting

confidence: 55%

California State Waters Map Series — Monterey Canyon and vicinity, California

Dartnell¹,

Maier²,

Erdey³

et al. 2016

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Section: Thickness and Depth To Base Of Uppermost Pleistocene And Holsupporting

confidence: 55%

California State Waters Map Series — Monterey Canyon and vicinity, California

Dartnell¹,

Maier²,

Erdey³

et al. 2016

Open-File Report

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“…Farther downstream, at section A, the mid-channel bar resembles the linear subaqueous ridges that often form in river mouths of tide-dominated systems [Wright, 1977]. These ridges are thought to be generated by lateral convergence of sediment from ebb-dominated and flood-dominated channels.…”

Section: Geomorphic Responsementioning

confidence: 99%

Sediment dynamics in the lowerMekongRiver: Transition from tidal river to estuary

et al. 2015

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A better understanding of flow and sediment dynamics in the lowermost portions of large‐tropical rivers is essential to constraining estimates of worldwide sediment delivery to the ocean. Flow velocity, salinity, and suspended‐sediment concentration were measured for 25 h at three cross sections in the tidal Song Hau distributary of the Mekong River, Vietnam. Two campaigns took place during comparatively high‐seasonal and low‐seasonal discharge, and estuarine conditions varied dramatically between them. The system transitioned from a tidal river with ephemeral presence of a salt wedge during high flow to a partially mixed estuary during low flow. The changing freshwater input, sediment sources, and estuarine characteristics resulted in seaward sediment export during high flow and landward import during low flow. The Dinh An channel of the Song Hau distributary exported sediment to the coast at a rate of about 1 t s−1 during high flow and imported sediment in a spatially varying manner at approximately 0.3 t s−1 during low flow. Scaling these values results in a yearly Mekong sediment discharge estimate about 65% smaller than a generally accepted estimate of 110 Mt yr−1, although the limited temporal and spatial nature of this study implies a relatively high degree of uncertainty for the new estimate. Fluvial advection of sediment was primarily responsible for the high‐flow sediment export. Exchange‐flow and tidal processes, including local resuspension, were principally responsible for the low‐flow import. The resulting bed‐sediment grain size was coarser and more variable during high flow and finer during low, and the residual flow patterns support the maintenance of mid‐channel islands.

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“…As a whole, the lower part of the topset sediments and underlying foreset and bottomset deposits constitute a rivermouth bar showing a Gilbert-type profile that was deposited in a delta-front environment (Wright 1977). As observed in recent deltaic environments, the narrow river-mouth bars typically show a lunate shape in plan view (bar crests), and their deposition is related to inertia-dominated effluent diffusion (Wright 1977). The upper topset deposits, composed of channel-fill sediments, levee deposits, and finergrained sediments that accumulated in interdistributary troughs and open bay settings, represent a delta-plain environment (Fisk 1961;Coleman and Gagliano 1965;Donaldson et al 1970;Gould 1970).…”

Section: Topset Depositsmentioning

confidence: 99%

“…The lower sediment package (ϳ2.5 m thick), comprising multistory, erosional sandstone beds with planar and trough crossstratification, is interpreted as upper delta-front deposits which accumulated mainly under the influence of fluvial discharge and which represent the subaqueous part of the topset deposits (Coleman and Gagliano 1965). As a whole, the lower part of the topset sediments and underlying foreset and bottomset deposits constitute a rivermouth bar showing a Gilbert-type profile that was deposited in a delta-front environment (Wright 1977). As observed in recent deltaic environments, the narrow river-mouth bars typically show a lunate shape in plan view (bar crests), and their deposition is related to inertia-dominated effluent diffusion (Wright 1977).…”

Section: Topset Depositsmentioning

confidence: 99%

Architecture of a Bench-Type Carbonate Lake Margin and Its Relation to Fluvially Dominated Deltas, Las Minas Basin, Upper Miocene, Spain

Calvo¹,

Gómez‐Gras²,

Alonso-Zarza³

et al. 2000

Journal of Sedimentary Research

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The Upper Miocene stratigraphic succession of the Las Minas Basin, located at the external zone of the Betic Chain in SE Spain, preserves several examples of lake carbonate bench deposits. Excellent exposures of the carbonate benches allow detailed observation of the architecture of these sediments and provide new insights for the ''steep-gradient bench margin-low energy'' model proposed by Platt and Wright (1991). The lake carbonate benches developed in close association with fluvially dominated shallow deltas that exhibit typical Gilbert-type profiles. The delta sequences comprise bottomset prodelta marl facies, distal to proximal foreset facies, deposited mainly in a delta-front environment, and topset facies, the latter reflecting both subaqueous delta-front and subaerial delta-plain environments. The development of the carbonate benches was constrained by the convexupward morphology of the deltaic deposits, which led to the available accommodation space for the growth of the steep-gradient platforms. The benches display a progradational pattern characterized by sigmoid-oblique internal geometries and offlap upper boundary relationships, which suggests that the carbonate benches developed under slow though continuous lake-level rise. Both the dimensions of the benches and the dominant carbonate components (i.e., encrusted charophyte stems and calcified cyanobaterial remains), allow comparisons with the progradational marl benches recognized in modern temperate hardwater lakes. Accordingly, the case study presented here provides a good ancient sedimentary analog for low-energy lake carbonate benches. Moreover, the evolutionary trend inferred from the fossil example offers new insights into the depositional conditions of this type of sediment and allows recognition of the transitional pattern from bench to ramp carbonate lake margins.

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Sediment transport and deposition at river mouths: A synthesis

Cited by 572 publications

References 0 publications

California State Waters Map Series — Monterey Canyon and vicinity, California

California State Waters Map Series — Monterey Canyon and vicinity, California

Sediment dynamics in the lowerMekongRiver: Transition from tidal river to estuary

Architecture of a Bench-Type Carbonate Lake Margin and Its Relation to Fluvially Dominated Deltas, Las Minas Basin, Upper Miocene, Spain

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