Consolidation, settlement, geochemical processes, and faulting all affect and contribute to subsidence. Barrier islands are also formed as part of this cycle of growth and decay. The landscape of the abandoned delta is changed by the marine processes mentioned previously. While the Gulf waves rework the shoreline, the interior marsh habitats break apart and subside leaving shallow open bays. This detachment of the barrier shoreline from the mainland leads to the formation of the barrier islands.
Barrier islands are transitory.
The forces of the Gulf continue to shape these fragile islands.