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  | isbn    = 0891813071

  | isbn    = 0891813071

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[[File:Paraná_Delta_near_Rosario.jpg|thumb|300px|Semi-flooded islands in the Upper Delta, off the coast of Rosario, Argentina.]]

[[File:Paraná_Delta_near_Rosario.jpg|thumb|300px|Semi-flooded islands in the Upper Delta, off the coast of Rosario, Argentina. Photo by [https://commons.wikimedia.org/wiki/User:Pablo-flores Pablo D. Flores].]]

The upper delta plain lies above the level of effective saltwater intrusion and is unaffected by marine processes. Most of the sediments comprising this part of the delta plain originate from the migratory tendency of [[distributary channel]]s, [[overbank]] flooding during annual highwater periods, and periodic breaks in the river banks, in which "crevassing" into adjacent lake basins occurs. The major environments of deposition include braided channels, meandering channels (point bars and meander-belt deposits), lacustrine delta fill, backswamps, and flood plains (swamps, marshes, and freshwater lakes).

The upper delta plain lies above the level of effective saltwater intrusion and is unaffected by marine processes. Most of the sediments comprising this part of the delta plain originate from the migratory tendency of [[distributary channel]]s, [[overbank]] flooding during annual highwater periods, and periodic breaks in the river banks, in which "crevassing" into adjacent lake basins occurs. The major environments of deposition include braided channels, meandering channels (point bars and meander-belt deposits), lacustrine delta fill, backswamps, and flood plains (swamps, marshes, and freshwater lakes).