Markewich, H. W., and William Markewich. 1994. An Overview of Pleistocene and Holocene Inland Dunes in Georgia and the Carolinas--Morphology, Distribution, Age, and Paleoclimate U.S. Geological Survey Bulletin #2069.
p. 25. While studying the Pleistocene fluvial and marine stratigraphy of the Cape Fear River valley, Markewich and Soller (1983) and Soller (1988) suggested that Carolina bays formed between 60 ka and 200 ka, thus supporting Frey's (1951) estimate of 100 ka for Singletary Lake, a large bay in the Cape Fear River valley. Soller (1988) considered it probable that some of the older dunes [poster's note: the authors are referring here to large, amorphous or dune-and-kettle type dunes on the northeastern terraces of coastal blackwater streams, not to bay rims] were formed contemporaneously with the Carolina bays, and that the younger dunes [poster's note: these "younger dunes" include bay rims] greatly postdated the bays, and that some dunes were as young as 5 ka.
This dune dating makes sense to me. While working in Marlboro County, SC, I found an Indian artifact about 3 feet down in one of those "younger dunes" along the Great Pee Dee River, which allowed me to date the dune to around 4500 BC.
Oops, "dune-and-kettle" should have read, "knob-and-kettle". Sorry for the typo.