ORIGIN, EVOLUTION, AND DEMISE OF THE DOUBLE BARRIER ISLAND SYSTEM OF NORTHEASTERN NORTH CAROLINA’S OUTER BANKS
During lower stages of Holocene sea-level, the flooding shoreline occurred around the subaerial ridge of the interstream divide as a strandplain beach. This shoreline eroded wave-cut platforms and scarps into the Pleistocene sediment units, producing sand for the associated beaches. As rising sea level overtopped the interstream divide during the late Holocene, two barrier island systems formed along the eastern and western perimeters of the broad ridge. During the last several hundred years of sea-level rise, most of the smaller-scale, sediment-poor Pamlico barrier islands have systematically collapsed into a broad system of intertidal and subtidal shoals. Cedar Island has adequate sediment sources and is the only surviving and healthy island of the Pamlico barrier system. Bird and Gull islands are in their final stages of collapse. The smaller-scale Pamlico barrier system serves as a model for the future evolution of the larger-scale Outer Banks barrier system, which already contains island segments in similar stages of collapse.