Where are barrier islands located?

Barrier islands

Elongate, narrow accumulations of sediment which have formed in the shallow coastal zone and are separated from the mainland by some combination of coastal bays and marshes. They are typically several times longer than their width and are interrupted by tidal inlets. Although their origin has been widely discussed, at least three possibilities exist: longshore spit development and subsequent cutting of inlets; drowning of old coastal ridges; and upward shoaling of subtidal sediment accumulations. All three may have occurred; however, the last seems most likely and most prevalent.

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