Date of Award

Spring 2010

Document Type

Legacy Thesis

Degree Name

Master of Science in Coastal Marine and Wetland Studies

Department

Coastal and Marine Systems Science

College

College of Science

First Advisor

Eric Wright

Second Advisor

Kevin S. Godwin

Third Advisor

M. Scott Harris

Additional Advisors

Douglas Nelson

Abstract

The site location for this investigation was Sandy Island, a 9,164 acre undeveloped riverine island located at the juncture of the Waccamaw and Pee Dee Rivers in Georgetown County, South Carolina. The objective of this investigation included a delineation of the surficial geology of the island and the use of landscape characteristics to create a predictive model for archaeological site locations. Geomorphology and anthropologic data were determined using a geographic information system while subsurface stratigraphy was determined from 13.65 trackline-kilometers of ground penetrating radar data ground-truthed using seven vibracores supplemented with outcrop observation. Data from this investigation were used to create paleogeographic and paleoclimatic reconstructions as well as geomorphic maps of Sandy Island. Sandy Island's surficial landscape can be classified into six separate categories, four of which are geomorphic features (field of east-west oriented dunes, field of northeastern-southwestern oriented dunes, southern most ridge, and floodplain), one ecological feature (wetlands), and a region to the south of anthropological modification. The east-west oriented dunes include 16 distinct ridges and are overlain by the younger northeastern-southwestern oriented dunes, which consists of 13 distinct ridges. Composing and underlying these surficial landscapes, seven geophysical stratigraphic units have been identified. The upper three units create the dune fields, with the east-west dune ridges having stratification that dips to the northeast and northeastern-southwestern dune ridges having stratification that dips to the southeast. All sediment analysis samples from vibracores collected within these upper units consist of medium to coarse grained, sub-angular frosted quartz, which is consistent with an eolian interpretation. Stratification of the slip faces was used to determine that the east-west dune ridges were influenced by prevailing winds from the southwest and the northeastern-southwestern dune ridges were influenced by ·winds from the northwest, suggesting at least two separate dune forming episodes. These episodes most likely occurred between 10ka and 40ka, the same period in which other geological features (Pee Dee River dunes and Carolina Bays) formed in the Southeastern United States. The predictive model of archeological sites did not yield any significant results, but the results of this model conclude that distance to water and aspect contributed significantly to differences between known and pseudo-absence points.

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