Geological influences on the Lower Mississippi River and its alluvial valley

Studies of photographs, maps, and channel morphology permit identification of greatly different Mississippi River reaches. From this, it becomes apparent that this large alluvial river is not monotonous in appearance, and therefore, it is not completely controlled by hydrology and hydraulics. In fact, the Mississippi River has reacted to uplift, faults, clay plugs, outcrops of Tertiary clay, and Pleistocene gravel in its bed, and tributaries. This classic example of a large alluvial river has major geological controls on its shape, pattern, and magnitude of change through time. In addition, the same controls plus the effect of plutonic intrusives and fault zones have significantly affected smaller rivers and the alluvial valley of the Mississippi River.