PALEOTEMPESTOLOGY UPON THE SOUTH CAROLINA COASTLINE: A CALIBRATION OF THE SEDIMENTARY HISTORICAL RECORD

Paleotempestological studies on decadal to millennial timescales rely largely on preserved overwash events in coastal pond/marsh sediments to determine the frequency of prehistoric hurricane events. Continuous long-term records of hurricane frequency and sample sites located in areas where hurricane tracks reflect climatic oscillations are essential for calibration. In this study, two sites in South Carolina (Middleton Pond Arcadia Plantation, Georgetown County; Moccasin Pond Bull’s Island, Charleston County) were assessed and chosen due to their proximity to the coast, natural geomorphology, their location within the tracts of multiple recent tropical cyclone events, and the availability of a 250-year documentary reconstruction of South Carolina tropical cyclones.

Ten vibra- and push cores from Middleton Pond contain sands that vary from fine to medium in grain size and range in color from tan to dark gray. There are three visible events in which sands abruptly contact lacustrine sediments, indicating either hurricane or storm activity. Deeper within the cores, oysters shells suggest that these sediments may have experienced a marine versus freshwater environment as well. Six cores from Moccasin Pond also contain several visible sand layers apparently deposited from lateral storm flooding via an inlet from the northwest. The lower portions of these cores are similar to those of Middleton Pond with the exception that no oyster shells are present. Future analyses include radioisotope age-dating and micro-scale image analysis using the Pierre Francus method in order to determine smaller scale structures resulting from flooding and overwash events.