Alluvial plain

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Events of the Pleistocene left their mark on major U.S. rivers. A conspicuous band of alternating Pleistocene (pale yellow) and Holocene (gray) deposits characterizes the broad, flat alluvial plain of the Mississippi River Embayment, its tributaries to the west, and coastal Texas. The irregularly striped pattern owes its origin to extensive and accelerated deposition by streams during interglacial phases of the Pleistocene
Events of the Pleistocene left their mark on major U.S. rivers. A conspicuous band of alternating Pleistocene (pale yellow) and Holocene (gray) deposits characterizes the broad, flat alluvial plain of the Mississippi River Embayment, its tributaries to the west, and coastal Texas. The irregularly striped pattern owes its origin to extensive and accelerated deposition by streams during interglacial phases of the Pleistocene
Alluvial plain is a relatively flat landform created by the deposition of sediment over a long period of time by one or more rivers coming from highland regions, from which alluvial soil forms.

As the highlands erode due to weathering and water flow, the sediment from the hills is transported to the lower plain. Various creeks will carry the water further to a river, lake, bay, or ocean.

As the sediments are deposited during flood conditions in the floodplain of a creek, the elevation of the floodplain will be raised. As this reduces the channel floodwater capacity, the creek will, over time, seek new, lower paths, forming meanders (a curving sinuous path).

The leftover higher locations, typically natural levees at the margins of the flood channel, will themselves be eroded by lateral stream erosion and from local rainfall and possibly wind transport if the climate is arid and does not support soil-holding grasses. These processes, over geologic time, will form the plain - a region with little relief (local changes in elevation), yet with a constant but small slope.


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[edit] Reference

  1. Wikipedia Alluvial plain [1]

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