GEOLOGIC FRAMEWORK OF A NORTHEASTERN SOUTH CAROLINA BARRIER ISLAND: WAITES ISLAND

While studies have focussed on the development of the extensive wave-dominated barrier islands of the Outer Banks of North Carolina and the prominent mixed energy barriers islands of the central South Carolina, the barrier islands located between these two areas have received much less attention. This study examines the geologic framework of Waites Island located in northeastern South Carolina. Waites Island is 5 km in length and over 0.5 km in width, of which Coastal Carolina University has access to the southern half. Along the southern half, seaward dunes are well developed. A prominent landward ridge, separated by high marsh, diverges from the island southward. To determine the stratigraphy of this section of the island, particularly the landward ridge, over 15 vibracores were collected along two shore-normal transects and a single shore-parallel transect. Vibracores were split, photographed and visually described for color, texture, grain size, organic composition and bedding. To determine the age of formation, organic rich sediments underlying the ridge have been sent for bulk radiocarbon analysis. Based on lithologic interpretation, five depositional environments are defined: washover/barrier sand, salt marsh, back-barrier intertidal, back-barrier subtidal and freshwater peat. Geomorphology and stratigraphy indicate that the landward ridge developed as washover infilled back-barrier environments during the Holocene sea-level rise.