ARCHITECTURE AND EVOLUTION OF A NORTHEASTERN SOUTH CAROLINA BARRIER ISLAND COMPLEX

This on-going study examines the geologic evolution of DeBordieu Island as part of a larger mapping project of northeastern South Carolina barrier island complexes by the USGS-SC Sea Grant Coastal Erosion Cooperative. Ground penetrating radar profiles, collected using a GSSI system with a 200 MHz antennae, combined with vibracore data indicate an attached northern end of the barrier island consisting of modern beach and landward marsh sediments overlying pre-transgressive sand. To the south, the island consists of a transgressive landward ridge of seaward dipping beach sand overlaying marsh and tidal creek sediments. At the southern end of the island, two recurved shorelines of seaward dipping beach sands evolved as the island prograded seaward. Historical aerial photographs indicate subsequent shoreline erosion of a portion of the seaward shoreline. Results from this study will be compared with other previously studied barrier complexes in the region to better understand and model the Grand Strand coastal system.