GEOARCHAEOLOGICAL INVESTIGATIONS OF CAROLINA BAY SAND RIMS IN THE CENTRAL SAVANNAH RIVER AREA, SOUTH CAROLINA: DIFFERENTIATING THE UNDIFFERENTIATED

This research focuses on understanding site formation processes, particularly as they relate to archaeological site burial and preservation within shallow Carolina bay sand rims in the Central Savannah River Area of South Carolina. Specifically, we are interested in identifying natural and cultural site-formation processes at three bays: Flamingo Bay (38AK469); Johns Bay (38AL246); and Frierson Bay (38BR1319 and 1320) in Aiken, Allendale, and Barnwell Counties, respectively. The most intensive investigations have been conducted at Flamingo Bay.

The comparative analysis of data sets from multiple sand rims has enabled the study of paleoenvironmental processes affecting rim accretion, erosion, pedology and artifact taphonomy. A primary objective has been the delineation of a detailed geochronology of landform development based on OSL and radiocarbon dating as well as temporally diagnostic artifacts. Another objective has been the comparative analysis of high resolution sequences of sediment samples employing a range of geoarchaeological techniques including: granulometry, soil chemistry, biogenic silica, environmental magnetism (magnetic susceptibility), sediment bulk density, loss on ignition (LOI), field water content, and sediment micromorphology. Ground Penetrating Radar (GPR) surveys were conducted to broadly delineate bay rim stratigraphy and geomorphology.

Thus far, twenty-eight chronometric dates have been obtained for bay sand rims, including 13 single-grain luminescence (OSL) age estimates and 15 AMS radiocarbon dates on charred hickory nut. OSL and ¹⁴C age estimates indicate that bay sand rims have actively accreted sands episodically throughout much of the Holocene. A basal sand rim OSL age from Johns Bay indicates formation of this sand rim in the late Pleistocene during Marine Oxygen Isotope Stage (MIS) 3. Earlier basal OSL dating at Flamingo Bay produced MIS 5 age-estimates. Evidence for bay migration and multiple rim formation is also indicated.

This research has broad relevance to understanding site formation processes at other, typically shallow, sandy and “stratigraphically undifferentiated” Coastal Plain archaeological sites. Many such sites are often written off by archaeologists as lacking integrity, or by geologists as "undifferentiated Quaternary alluvium".