Coastal Classification Atlas

Geologic Setting

The Gulf coast of Alabama and Mississippi between Perdido Pass and Cat Island consists of sandy beaches and barrier islands (Canis and others, 1985). Some segments of the barrier islands in eastern Alabama (Perdido Key and Morgan Peninsula) are characterized by beach ridges and other segments are narrow barriers that are overwashed frequently. One short headland segment where there is no barrier is near Gulf Shores. Dauphin Island has high dunes and a pine forest on its eastern end, but its western end is a low profile barrier that is frequently overwashed. The Mississippi coast is composed of a chain of barrier islands separated by wide tidal inlets. The barrier islands are low, narrow, and generally migrating to the west due to the westerly alongshore currents. Hurricane channels periodically cut Mississippi coast barriers, such as in 1969 when Camille Cut bisected Ship Island. The beach sand of the Alabama-Mississippi shore typically contains some broken shell material as a result of high production of mollusks in the clear warm water of the Gulf of Mexico and an absence of rivers that would supply additional sand.

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