STRATIGRAPHIC ARCHITECTURE OF THE CONWAY PALEO-BARRIER SYSTEM OF NORTHEASTERN, SOUTH CAROLINA

Emergent paleo-barrier systems alternating with back barrier flats dominate the geomorphology of Horry County in northeastern South Carolina. This study examines the geomorphology and radar stratigraphy of the Conway Barrier system, one of four major paleo-barriers systems in Horry County. As identified on LIDAR data, the barrier system is comprised of a pair of ridges to the south and a single ridge to the north. The ridge systems extend for over 30 km’s in length and ridges are typically <1 km in width and <7 m in height. To better refine the internal architecture of the 12 km long ridge system to the south, ground penetrating radar (GPR) data has been collected by Marine Geology laboratories (MSCI 304L) at Coastal Carolina University. This study compiles these data, which forms a loose grid of over 30 trackline-km’s across the entire barrier system. A GSSI system with 200MHz antenna was used for GPR data collection. Position locations were determined by GPS and topographic elevation along each transect was extracted from LIDAR elevations using a GIS. The data were processed using gain, high and low pass filtering, and surface normalization. GPR stratigraphy from the southern end of the studied barrier system reveals (1) the landward ridge is composed of flatter lying reflectors and landward clinoforms (overwash deposits) indicating retrogradational to aggradational development and (2) the more seaward ridge composed of seaward clinofom facies of later prograding barrier development. Highly accurate positioning and visualization of the GPR imaging of these ridges refine our understanding of the internal architecture and evolution of these paleo-barrier systems.