Recent and subrecent changes in the dispersal of amazon mud

Eisma, D.; Augustinus, Pieter G.E.F.; Alexander, Clark

doi:10.1016/0077-7579(91)90016-t

Cited by 120 publications

(84 citation statements)

References 18 publications

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“…6). The crossshore amplitudes of the resulting mudbanks range from 10 to 30km, and in the alongshore directions they are between 10 and 50 km wide (Augustinus 1987;Froidefond et al 1988;Augustinus et al 1989;Eisma et al 1991). These banks, which absorb on the order of 90% or more of the incoming wave energy, migrate westward at a rate that varies between 0.5 and 2.5 km a -1 in ~b° a.…”

Section: Muddy Coastsmentioning

confidence: 99%

“…In this event, wave breaking, which can suspend and advect significant quantities of mud and thereby influence bottom profile evolution, tends to be weak and confined to a narrow littoral zone (Wells 1983;Mathew et al 1995). Yet field observations suggest that even in that environment mud is transported, both cross-shore and alongshore, at significant rates (Wells 1983;Eisma et al 1991;Mathew & Baba 1995). A question which naturally arises is: by what mechanism does this transport occur?…”

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confidence: 99%

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Considerations on wave-induced fluid mud streaming at open coasts

Rodriguez

Mehta

1998

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Wave-induced streaming of fluid mud at open coasts under damped, nonbreaking waves is examined as a likely mechanism to explain nearshore bottom evolution in such an environment. For a two-layered, water-fluid mud domain in which mud is considered to be a viscous continuum, an expression for the streaming velocity is obtained. Preliminary data on alongshore streaming of fluid mud in a wave basin show an order of magnitude agreement with theory. Previous observations on the rates of mud movement along the coasts of Surinam, Guyana and Louisiana are shown to yield alongshore velocities that are commensurate with those obtained by considering streaming to be the prevalent cause of mud transport. These velocities are considerably lower than those which would occur due to breaking waves. Off the southwestern coast of India, shoreward streaming of mud under monsoonal waves results in the formation of shore-fast mudbanks. It is argued that among transport mechanisms which govern the dynamics of microtidal muddy coasts, streaming may be an important means by which fluid mud influences the formation, migration and dissipation mudbanks in areas where wave breaking is significantly attenuated by viscous damping.

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Section: Muddy Coastsmentioning

confidence: 99%

mentioning

confidence: 99%

Considerations on wave-induced fluid mud streaming at open coasts

Rodriguez

Mehta

1998

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“…Kuehl et al (1986) ) is transported northwestward along the shelf toward the Guiana and Orinoco coast Kuehl et al, 1986). Approximately half the sediment transported northwest of the Amazon Delta to the Guiana coast is in the form of turbid suspensions (100 to 1000 mg l À1 ), whereas the other half is in a less concentrated form along the middle shelf and is advected northwestward by the North Equatorial Current (Eisma et al, 1991;Colin and Bourles, 1992).…”

Section: Amazon River and Deltamentioning

confidence: 99%

Regional controls on geomorphology, hydrology, and ecosystem integrity in the Orinoco Delta, Venezuela

et al. 2002

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Interacting river discharge, tidal oscillation, and tropical rainfall across the 22,000 km 2 Orinoco delta plain support diverse fresh and brackish water ecosystems. To develop environmental baseline information for this largely unpopulated region, we evaluate major coastal plain, shallow marine, and river systems of northeastern South America, which serves to identify principal sources and controls of water and sediment flow into, through, and out of the Orinoco Delta. The regional analysis includes a summary of the geology, hydrodynamics, sediment dynamics, and geomorphic characteristics of the Orinoco drainage basin, river, and delta system. Because the Amazon River is a major source of sediment deposited along the Orinoco coast, we summarize Amazon water and sediment input to the northeastern South American littoral zone. We investigate sediment dynamics and geomorphology of the Guiana coast, where marine processes and Holocene history are similar to the Orinoco coast. Major factors controlling Orinoco Delta water and sediment dynamics include the pronounced annual flood discharge; the uneven distribution of water and sediment discharge across the delta plain; discharge of large volumes of water with low sediment concentrations through the Río Grande and Araguao distributaries; water and sediment dynamics associated with the Guayana littoral current along the northeastern South American coast; inflow of large volumes of Amazon sediment to the Orinoco coast; development of a fresh water plume seaward of Boca Grande; disruption of the Guayana Current by Trinidad, Boca de Serpientes, and Gulf of Paria; and the constriction at Boca de Serpientes. D

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“…Much Amazon sediment is incorporated into fluid-mud suspensions on the inner shelf (Kineke and Sternberg, 1995;Kineke et al, 1996). Amazon sediment also affects coastal regions up to 1000 km north of the river mouth, promoting mudflat progradation and chenier plain growth in northern Brazil, French Guiana, Surinam, and Guyana (Figure 3-20; e.g., Delft Hydraulics Laboratory, 1962;Vann, 1969;Eisma, 1971;Wells and Coleman, 1981a, b;Augustinus et al, 1989;Daniel, 1989;Prost, 1989;Eisma et al, 1991;Allison et al, 1995aAllison et al, , b, 2000bAllison and Lee, in press). The structure and dynamics of mud deposits near the Amazon mouth and along the northeastern South American coast were studied as part of the AmasSeds (A Multidisciplinary Amazon Shelf Sediment Study)…”

Section: Two Analogues For the Louisiana Chenier Plainmentioning

confidence: 99%

“…Accretion rates, determined from aerial photography and field investigations, follow a decadal cycle of trade wind intensity (-30 year period), and are highest when trade winds are strongest (Vann, 1969;Eisma et al, 1991). When trade winds are weak, mudflats may experience non-deposition or erosion (Allison et al, 1995a(Allison et al, , 2000b.…”

Section: Two Analogues For the Louisiana Chenier Plainmentioning

confidence: 99%

Fine-grained sedimentation on the Chenier Plain Coast and inner continental shelf, northern Gulf of Mexico

Draut¹

2003

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Recent and subrecent changes in the dispersal of amazon mud

Cited by 120 publications

References 18 publications

Considerations on wave-induced fluid mud streaming at open coasts

Considerations on wave-induced fluid mud streaming at open coasts

Regional controls on geomorphology, hydrology, and ecosystem integrity in the Orinoco Delta, Venezuela

Fine-grained sedimentation on the Chenier Plain Coast and inner continental shelf, northern Gulf of Mexico

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