STRATIGRAPHY AND GEOMORPHOLOGY OF A NORTHEASTERN SOUTH CAROLINA BARRIER ISLAND: WAITES ISLAND

Located in the transition between the more extensively studied wave-dominated barrier islands of North Carolina and the mixed-energy barrier islands of Central South Carolina, Waites Island is a 5 km long and 0.5 km wide barrier island situated at the northern end of South Carolina’s Grand Strand arcuate coastal system. Building upon previous stratigraphic studies along the western third of the island, this study examines the island’s central and eastern portions. In this region, the island is composed of a broad landward ridge, a brackish low and seaward dune and beach system. To determine the geologic development, ground-penetrating radar (GPR) data were collected along three, shore-normal transects and one, shore-parallel transect. To ground truth this data, twelve vibracores were collected along the GPR transects. Vibracores were split and described for color, texture, components, and sedimentary structures. These data show a seaward dune sand overlying beach sand; central brackish marsh overlying overwash sand, marsh muddy sand and marine sand; and landward dune sand overlying a series of overwash sand and back-barrier marsh mud. Coupled with side-scan sonar and chirp data on the seaward shelf, this project will provide a better understanding of sand accumulation within the northern portion of the Grand Strand coastal system and barrier island development within this transitional setting.