FLUVIAL RESPONSE OF THE CAPE FEAR RIVER TO LATE QUATERNARY CLIMATE CHANGE

Warming temperatures and increased precipitation at the end of the Last Glacial Maximum caused a change in the channel patterns of many of the rivers in the southeastern United States. Around 15 ka, the affected rivers transitioned from braided river channels to large meandering channels with scroll bar features. As temperatures continued to increase and effective precipitation rates decreased, the meanders grew smaller until they reached their modern day morphology. In the Cape Fear River valley, located in southeastern North Carolina, these fluvial transitions are recorded in abandoned late Pleistocene river terraces. The Socastee and Wando terraces both appear to be relict braided channels with aeolian sand cover. The morphology of the backswamp on the modern floodplain indicates that it may have been part of a paleomeander. Analysis of two cross-valley profiles is used to characterize the topographic, stratigraphic, and sedimentological relationships between the terrace surfaces and the modern floodplain. Pending OSL and radiocarbon dates will determine the timing of fluvial transitions in this area and will be used to compare the timing of those transitions with the existing and paleoecological and paleoclimatic data for the region. The objective of the study is to construct a chronology of fluvial response of the Cape Fear River to late Quaternary fluctuations in climate and vegetation.