Sediment Distribution Patterns Offshore of a Renourished Beach: Atlantic Beach and Fort Macon, North Carolina

Abstract

Contour plots of sediment characteristics have been used to help delineate the regional distribution of native, renourishment, and relict sediments off a renourished beach on the central North Carolina coast. Shell color, shell polish, and sediment size (sorting) were found to be especially useful indicators of dispersal patterns of renourishment sands, which were characterized by a high percentage of fine-grained sediment and a high percentage of dull, pockmarked shell that was gray-to-black in color. Distribution patterns show that longshore transport of renourishment sediment has been minor and little sand from a recent renourishment project was supplied to the adjacent native beaches. However, possible cross-shore transport was identified in storm layers (shell hash) in offshore sediment cores, and additional evidence was provided by the rippled scour depressions noted in a recent side-scan sonar survey.